U.S. patent application number 13/330669 was filed with the patent office on 2012-05-10 for exercise apparatus with automatically adjustable foot motion.
Invention is credited to Daniel J. BEDELL, Joseph D. MARESH, Kenneth W. STEARNS.
Application Number | 20120115685 13/330669 |
Document ID | / |
Family ID | 42784989 |
Filed Date | 2012-05-10 |
United States Patent
Application |
20120115685 |
Kind Code |
A1 |
BEDELL; Daniel J. ; et
al. |
May 10, 2012 |
EXERCISE APPARATUS WITH AUTOMATICALLY ADJUSTABLE FOOT MOTION
Abstract
An elliptical exercise apparatus includes a frame, a pair of
footpads, and a linkage coupling the footpads to the frame and for
guiding the footpads in closed paths when a user's feet apply
forces to the footpads. The linkage, which includes a rotatable
member having an angular position indicative of the positions of
the footpads within their closed paths, responds to input control
signals by adjusting length and height dimensions of the closed
paths. A control system senses the angular position of the
rotatable member, senses the forces the user applies to the
footpads, and generates the control signals to increase or decrease
the path dimensions when it senses particular combinations of
angular position and user forces, thereby permitting the user to
control the path dimensions by controlling the forces applied to
the footpads.
Inventors: |
BEDELL; Daniel J.;
(Alexandria, VA) ; MARESH; Joseph D.; (West Linn,
OR) ; STEARNS; Kenneth W.; (Houston, TX) |
Family ID: |
42784989 |
Appl. No.: |
13/330669 |
Filed: |
December 19, 2011 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
12411257 |
Mar 25, 2009 |
8079937 |
|
|
13330669 |
|
|
|
|
Current U.S.
Class: |
482/52 |
Current CPC
Class: |
A63B 2230/75 20130101;
A63B 22/001 20130101; A63B 21/005 20130101; A63B 2220/30 20130101;
A63B 2225/20 20130101; A63B 2071/0644 20130101; A63B 2022/0043
20130101; A63B 2071/065 20130101; A63B 2022/002 20130101; A63B
22/0664 20130101; A63B 2225/50 20130101; A63B 2022/067 20130101;
A63B 2022/0623 20130101; A63B 2225/09 20130101; A63B 2220/16
20130101; A63B 22/0015 20130101; A63B 2220/22 20130101; A63B
2220/51 20130101; A63B 2220/58 20130101 |
Class at
Publication: |
482/52 |
International
Class: |
A63B 22/04 20060101
A63B022/04 |
Claims
1. An exercise apparatus comprising: a frame; a footpad for
supporting a user's foot; a linkage for coupling the footpad to the
frame and for guiding the footpad in a closed path in response to a
force applied to the footpad by the user's foot, the linkage
including a rotatable member having an angular position indicative
of a position of the footpad within the closed path, wherein the
linkage adjusts a dimension of the closed path in response to an
electrical control signal supplied as input to the linkage; and a
control system for monitoring the angular position of the rotatable
member, for monitoring the force applied to the footpad, and for
generating the control signal such that the linkage adjusts the
dimension as a function of the monitored force on the footpad and
of the angular position of the rotatable member.
2. The exercise apparatus in accordance with claim 1 wherein the
control system generates the control signal to cause the linkage to
increase and decrease the path dimension when it senses particular
combinations the force and the angular position, thereby permitting
the user to control the path dimension by controlling the force
applied to the footpad.
3. The exercise apparatus in accordance with claim 2 wherein the
control system controls the control signal such that the linkage
alters the dimension when a magnitude of the force is outside a
magnitude range while the angular position of the rotatable member
is within a position range, such that the linkage refrains from
adjusting the dimension when the magnitude of the force is outside
the magnitude range, and such that the linkage refrains from
adjusting the dimension when the angular position of the rotatable
member is outside the position range.
4. The exercise apparatus in accordance with claim 1 further
comprising: a strain gauge coupled between the footpad and the
linkage for generating a force indicating signal indicative of the
magnitude of the force, wherein the control system monitors the
force by monitoring the force indicating signal.
5. The exercise apparatus in accordance with claim 1 wherein the
force and the dimension are in substantially parallel
directions.
6. The exercise apparatus in accordance with claim 1 wherein the
control system monitors the force by monitoring a rotational
velocity of the rotatable member, and based on the monitored
rotational velocity, determining a rotational acceleration of the
rotatable member that is indicative of the magnitude of the force
when the angular position of the rotatable member is within the
position range.
7. The exercise apparatus in accordance with claim 1 wherein the
dimension of the closed path defines a stride length of the user's
foot.
8. The exercise apparatus in accordance with claim 1 wherein the
dimension of the closed path defines a stride height of the user's
foot.
9. An exercise apparatus comprising a frame; a footpad for
supporting a user's foot; a linkage for coupling the footpad to the
frame and for guiding the footpad in a closed path in response to
first and second forces applied in first and second directions,
respectively, to the footpad by the user's foot, wherein the
linkage includes a rotatable member having an angular position that
changes with a position of the footpad within the closed path, and
wherein the linkage adjusts first and second dimensions of the
closed path in response to electrical control signals supplied as
inputs to the linkage; and a control system for monitoring the
angular position of the rotatable member, for monitoring magnitudes
of first and second forces, and for generating the control signals
such that the linkage adjusts the first and second dimensions as
functions of the monitored first and second forces and of the
monitored angular position of the rotatable member.
10. The exercise apparatus in accordance with claim 9 wherein the
control signals cause the linkage to increase and decrease the path
dimensions when it senses particular combinations of the angular
position and first and second forces, thereby permitting the user
to control the path dimensions by controlling the force applied to
the footpad.
11. The exercise apparatus in accordance with claim 10 wherein the
control system controls the first and second control signals such
that the linkage alters the first dimension when a magnitude of the
first force is outside a first magnitude range while the angular
position of the rotatable member is within a first position range,
such that the linkage refrains from adjusting the first dimension
when the magnitude of the first force is outside the first
magnitude range, and such that the linkage refrains from adjusting
the first dimension when the angular position of the rotatable
member is outside the first position range, and such that the
linkage alters the second dimension when a magnitude of the second
force is outside a second magnitude range while the angular
position of the rotatable member is within a second position range,
such that the linkage refrains from adjusting the second dimension
when the magnitude of the second force is outside the second
magnitude range, and such that the linkage refrains from adjusting
the second dimension when the angular position of the rotatable
member is outside the second position range.
12. The exercise apparatus in accordance with claim 9 further
comprising: a first strain gauge coupled between the footpad and
the linkage for generating a first force indicating signal
indicative of the magnitude of the first force, and a second strain
gauge coupled between the footpad and the linkage for generating a
second force indicating signal indicative of the magnitude of the
second force, wherein the control system monitors the first and
second forces by monitoring the first and second force indicating
signals.
13. The exercise apparatus in accordance with claim 9 wherein the
first dimension of the closed path defines a stride length of the
user's foot, and wherein the second dimension of the closed path
defines a stride height of the user's foot.
14. A method for controlling an exercise apparatus having a frame,
a footpad for supporting a user's foot, and a linkage for coupling
the footpad to the frame and for guiding the footpad in a closed
path in response to a force applied to the footpad by the user's
foot, wherein the linkage includes a rotatable member having an
angular position that changes with a position of the footpad within
the closed path, and wherein the linkage adjusts a dimension of the
closed path in response to an electrical control signal supplied as
input to the linkage, the method comprising the steps of a.
monitoring the angular position of the rotatable member, b.
monitoring a magnitude of the force, and c. controlling the control
signal such that the linkage adjusts the dimension as a function of
the monitored force on the footpad and of the monitored angular
position of the rotatable member.
15. The method in accordance with claim 14 wherein the control
signals cause the linkage to increase and decrease the path
dimension when it senses particular combinations of the monitored
angular position and the monitored force, thereby permitting the
user to control the path dimension by controlling the force applied
to the footpad.
16. The method in accordance with claim 14 wherein the exercise
apparatus includes a strain gauge coupled between the footpad and
the linkage for generating a force indicating signal indicative of
the magnitude of the force, and wherein step b comprises monitoring
the force indicating signal.
17. The method in accordance with claim 14 wherein step c comprises
controlling the control signal such that the linkage alters the
dimension when a magnitude of the force is outside a magnitude
range while the angular position of the rotatable member is within
a position range, such that the linkage refrains from adjusting the
dimension when the magnitude of the force is outside the magnitude
range, and such that the linkage refrains from adjusting the
dimension when the angular position of the rotatable member is
outside the position range.
18. The method in accordance with claim 17 wherein the force and
the dimension are in substantially parallel directions.
19. The method in accordance with claim 14 wherein step b comprises
the substeps of: b1. monitoring a rotational velocity of the
rotatable member, and b2. based on the monitored rotational
velocity, determining a rotational acceleration of the rotatable
member indicative of the magnitude of the force when the angular
position of the rotatable member is within the position range.
20. The exercise apparatus in accordance with claim 14 wherein the
dimension of the closed path defines a stride length of the user's
foot.
21. The method in accordance with claim 14 wherein the dimension of
the closed path defines a stride height of the user's foot.
22. A method for controlling an exercise apparatus having a frame,
a footpad for supporting a user's foot, and a linkage for coupling
the footpad to the frame and for guiding the footpad in a closed
path in response to first and second forces applied in differing
directions to the footpad by the user's foot, wherein the linkage
includes a rotatable member having an angular position that changes
with a position of the footpad within the closed path, and wherein
the linkage adjusts first and second dimensions of the closed path
in response to a plurality of electrical control signals supplied
as inputs to the linkage, the method comprising the steps of a.
monitoring the angular position of the rotatable member, b.
monitoring magnitudes of first and second forces, and c.
controlling the control signals such that the linkage adjusts the
first and second dimensions as functions of the monitored first and
second forces and the monitored angular position of the rotatable
member.
23. The method in accordance with claim 22 wherein the control
signals cause the linkage to increase and decrease the path
dimensions when it senses particular combinations of the monitored
angular position and first and second forces, thereby permitting
the user to control the path dimensions by controlling the force
applied to the footpad.
24. The method in accordance with claim 22 wherein the exercise
apparatus includes a first strain gauge coupled between the footpad
and the linkage for generating a first force indicating signal
indicative of the magnitude of the first force, wherein the
exercise apparatus includes a second strain gauge coupled between
the footpad and the linkage for generating a second force
indicating signal indicative of the magnitude of the second force,
and wherein step b comprises monitoring the first and second force
indicating signals.
25. The method in accordance with claim 22 wherein step c comprises
controlling the first and second control signal such that the
linkage alters the first dimension when a magnitude of the first
force is outside a first magnitude range while the angular position
of the rotatable member is within a first position range, such that
the linkage refrains from adjusting the first dimension when the
magnitude of the first force is outside the first magnitude range,
and such that the linkage refrains from adjusting the first
dimension when the angular position of the rotatable member is
outside the first position range, and such that the linkage alters
the second dimension when a magnitude of the second force is
outside a second magnitude range while the angular position of the
rotatable member is within a second position range, such that the
linkage refrains from adjusting the second dimension when the
magnitude of the second force is outside the second magnitude
range, and such that the linkage refrains from adjusting the second
dimension when the angular position of the rotatable member is
outside the second position range.
26. The method in accordance with claim 22 wherein the first and
second forces are applied to the footpad in substantially
orthogonal directions.
27. The method in accordance with claim 22 wherein the first and
second dimensions are in substantially orthogonal directions.
28. The method in accordance with claim 22 wherein the first
dimension of the closed path defines a stride length of the user's
foot, and wherein the second dimension of the closed path defines a
stride height of the user's foot.
29. An exercise apparatus comprising: a frame, a right footpad for
supporting a user's right foot, a left footpad for supporting the
users left foot, a linkage for coupling the right and left footpads
to the frame and for guiding the right and left footpads in a
closed pats in response to forces applied to the right and left
footpads by the user's right and left feet, the linkage including a
rotatable member having an angular position indicative of positions
of the right and left footpads within their closed paths, wherein
the linkage adjusts dimensions of the closed paths of the right and
left footpads in response to electrical control signals supplied as
inputs to the linkage, and a control system for monitoring the
angular position of the rotatable member, for monitoring the forces
applied to the right and left footpads, and for generating the
control signals such that the linkage adjusts at least one
dimension of the right footpad as a function of monitored force on
the right footpad and of the angular position of the rotatable
member, and independently adjusts at least one dimension of the
left foot pad as a function of monitored force on the left footpad
and of the angular position of the rotatable member.
30. The exercise apparatus in accordance with claim 29 wherein the
control system generates the control signals to cause the linkage
to increase and decrease the path dimensions of the right and left
footpads when it senses particular combinations the angular
position and the monitored forces, thereby permitting the user to
independently control the dimensions of the paths followed by the
right and left footpads by controlling the forces applied to the
right and left footpads.
31. The exercise apparatus in accordance with claim 30 wherein the
control system controls the control signals such that the linkage
alters the dimension of the closed path of the right footpad when a
magnitude of the force on the right footpad is outside a first
magnitude range while the angular position of the rotatable member
is within a first position range and otherwise refrains from
adjusting the dimension of the closed path of the right footpad;
and such that the linkage alters the dimension of the closed path
of the left footpad when a magnitude of the force on the left
footpad is outside a second magnitude range while the angular
position of the rotatable member is within a second position range
and otherwise refrains from adjusting the dimension of the closed
path of the left footpad,
32. A method for controlling an exercise apparatus having a frame,
a right footpad for supporting a user's right foot, a left footpad
for supporting the users left foot, and a linkage for coupling the
right and left footpads to the frame and for guiding the right and
left footpads in a closed pats in response to forces applied to the
right and left footpads by the user's right and left feet, the
linkage including a rotatable member having an angular position
indicative of positions of the right and left footpads within their
closed paths, wherein the linkage adjusts dimensions of the closed
paths of the right and left footpads in response to electrical
control signals supplied as inputs to the linkage, the method
comprising the steps of a. monitoring the angular position of the
rotatable member, b. monitoring the forces applied to the right and
left footpads, and c. generating the control signals such that the
linkage adjusts at least one dimension of the right footpad as a
function of monitored force on the right footpad and of the angular
position of the rotatable member, and independently adjusts at
least one dimension of the left foot pad as a function of monitored
force on the left footpad and of the angular position of the
rotatable member.
33. The method in accordance with claim 1 wherein the control
signals cause the linkage to increase and decrease the path
dimensions of the right and left footpads when in response to
particular combinations the angular position and the monitored
forces, thereby permitting the user to independently control the
dimensions of the paths followed by the right and left footpads by
controlling the forces applied to the right and left footpads.
34. The method in accordance with claim 33 wherein the control
signals cause the linkage alter the dimension of the closed path of
the right footpad when a magnitude of the force on the right
footpad is outside a first magnitude range while the angular
position of the rotatable member is within a first position range
and otherwise to refrain from adjusting the dimension of the closed
path of the right footpad, and wherein the control signals cause
the linkage alter the dimension of the closed path of the left
footpad when a magnitude of the force on the left footpad is
outside a second magnitude range while the angular position of the
rotatable member is within a second position range and otherwise to
refrain from adjusting the dimension of the closed path of the left
footpad.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to exercise apparatus, and
more specifically to an exercise apparatus that guides a user's
feet through automatically adjustable paths of motion.
[0003] 2. Description of Related Art
[0004] Running on treadmills remains a popular form of indoor
aerobic exercise even though it can lead to injuries. A runner hops
from foot-to-foot, stressing his or her lower extremities with
repetitive impact forces of each footfall that can eventually
injure joints and tendons. Running the equivalent of only ten miles
per day on a treadmill can expose each leg to 200,000 impacts per
year. Many other kinds of exercise apparatus, including stationary
bicycles, steppers, climbers, gliders and skiers, provide indoor
aerobic exercise that allow a user's feet to follow a closed path
without the impact stress associated with treadmills, however
despite the advantages of these apparatus, running on treadmills
remains popular. Since people are structurally better adapted to
run rather than to pedal, climb steps, glide or ski, they often
feel more comfortable running.
[0005] Elliptical exercise apparatus include foot support or pedals
following closed paths designed to mimic the non-circular paths a
user's feet trace out when running on a treadmill, but since the
user's feet do not leave the foot supports, the user can engage in
a running style of exercise without experiencing the repetitive
impacts associated with running on a treadmill. Since the user's
feet follow paths that are neither linear nor circular, they are
commonly called "elliptical" paths to distinguish them over the
circular closed paths provided stationary bicycle apparatus and the
linear or arcuate closed paths associated with steppers and skier,
gliders and climbers, even though an elliptical exercise apparatus
normally does not provide a truly elliptical foot path.
[0006] A typical elliptical exercise apparatus includes a crank
moving in a circular motion and a linkage mechanism coupling the
crank to its foot supports for converting the circular motion of
the crank into the "elliptical" motion of the foot supports. The
linkage also includes a resistance device such as a regenerative or
eddy current brake coupled to the crank for providing an adjustable
resistance to the foot motion for controlling the amount of work
the user must expend to move the foot supports. Examples of
elliptical exercise apparatus are disclosed in U.S. Pat. No.
4,185,622 to Swenson; U.S. Pat. No. 5,278,529 to Eschenbach, U.S.
Pat. No. 5,383,829 to Miller; U.S. Pat. No. 5,540,637 to Rodgers,
Jr.; U.S. Pat. No. 6,196,948 to Stearns et al.; and U.S. Pat. No.
6,468,184 to Lee, all of which are incorporated herein by
reference.
[0007] The height and length of a runner's stride varies depending
on running speed, on the terrain and on the runner's preferences.
While early elliptical exercise apparatus designs allowed a user to
engage in a running style of motion while avoiding the impact
stress associated with treadmills, the shape of the path the user's
foot followed was fixed and the user was not able to adjust either
the height or length of stride. Later elliptical exercise apparatus
designs allowed a user to adjust stride length. For example U.S.
Pat. No. 5,893,820 issued Apr. 13, 1999 to Maresh et al. describes
an elliptical apparatus allowing a user to adjust the shape of an
elliptical footpath by manually changing the linkage between the
crank and the foot supports. U.S. Pat. No. 5,919,118 issued Jul. 6,
1999 to Stearns et al. teaches to incorporate a linear actuator
into the linkage that can expand or contract to change the shape of
the linkage in response to a signal controlled by a user-operable
button on a control panel, thereby to change stride length.
Although these apparatuses allow a user to adjust stride length,
they required the user to stop the apparatus and manually alter the
linkage, or to operate a control knob or button while exercising,
either of which is inconvenient.
[0008] Still later designed elliptical exercise apparatuses
automatically adjust stride length or height. U.S. Pat. No.
6,206,804 issued Mar. 27, 2001 to Maresh describes an elliptical
exercise including dampers or springs in the linkage assembly
defining the user's footpath that automatically vary the path shape
in response to forces applied by the user's foot. U.S. patent
application 20050181911, filed Aug. 18, 2005 by Porth teaches an
elliptical exercise apparatus that senses the speed at which the
crank rotates in which the crank rotates and adjusts an actuator in
the linkage so that both stride length and height change with speed
and pedaling direction. While the apparatus automatically adjusts
stride length or height, there is no assurance that stride length
or height that is adjusted as a function of speed or direction will
match the user's desired stride length or height.
SUMMARY OF THE INVENTION
[0009] An elliptical exercise apparatus in accordance with the
invention includes frame, a pair of footpads for supporting the
user's feet, and a linkage coupling the footpads to the frame for
guiding the footpads in a closed paths when the user's feet apply
forces to the footpads. The linkage includes actuators that respond
to control signals by adjusting length and height dimensions of the
closed paths. The linkage also includes a rotatable member having
an angular position that is indicative of the positions of the
footpads within their closed paths.
[0010] The exercise apparatus further includes a control system
that senses the angular position of the rotatable member and, for
each footpad, senses the forces applied to the footpad and
generates the control signals for controlling the length and height
dimensions of the closed path as functions of the sensed angular
position and forces. The control system increases or decreases the
length and height dimensions of the closed path of each footpad
when the user-applied force on the footpad is outside a particular
magnitude range while the angular position of the rotatable member
is within a particular angular position range. The exercise
apparatus thus enables the user to independently control stride
height and length of each footpad by controlling magnitudes of the
forces the user applies to each footpad as it passes through a
particular section of its closed path.
[0011] In one embodiment of the invention, the control system
includes strain gauges attached to the footpads that sense user
applied forces. In another embodiment of the invention, the
controller determines user applied forces as functions of the
acceleration of the rotatable member.
[0012] The claims appended to this specification particularly point
out and distinctly claim the subject matter of the invention.
However those skilled in the art will best understand both the
organization and method of operation of what the applicants
consider to be the best modes of practicing the invention by
reading the remaining portions of the specification in view of the
accompanying drawings, wherein like reference characters refer to
like element
BRIEF DESCRIPTION OF THE DRAWING
[0013] FIG. 1 is a perspective view an exercise apparatus
constructed according to the principles of the present
invention.
[0014] FIGS. 2A and 2B are perspective views of a footpad of the
exercise apparatus of FIG. 2.
[0015] FIG. 3 is a left side elevation view of the exercise
apparatus of FIG. 1.
[0016] FIGS. 4 and 5 are perspective views of alternative versions
of a crank assembly for the exercise apparatus of FIG. 1.
[0017] FIGS. 6A-6D are simplified side elevations views of portions
of the exercise apparatus of FIG. 1.
[0018] FIG. 7 is a block diagram an exercise control, monitoring
and display system for the exercise apparatus of FIG. 1.
[0019] FIG. 8 is a plan view of the control panel of FIG. 1.
[0020] FIG. 9 is a diagram defining position of the crank member of
FIG. 1.
[0021] FIG. 10 depicts a software routine executed by the computer
of FIG. 7 for automatically controlling stride length.
[0022] FIG. 11 depicts a software routine executed by the computer
of FIG. 7 for automatically controlling stride height.
[0023] FIG. 12 graphically depicts the angular velocity and
acceleration of the crank member of the apparatus of FIG. 1 as
functions of angular position.
[0024] FIG. 13 is a block diagram depicting a subcircuit of I/O
circuit 118 of FIG. 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0025] The present invention may be implemented in connection with
exercise apparatus having a frame, user-operable footpads and a
linkage for coupling the footpads to the frame and for guiding the
footpads in closed paths. The invention relates in particular to a
method for automatically responding to user forces applied to the
footpads by adjusting one or more dimensions of the closed path
each foot support follows. Although the invention is illustrated
below as being used to control path dimensions in an elliptical
exercise machine, the invention may be used to control path
dimensions in other types of exercise machines having adjustable
path dimensions. Although there are many possible modes of
practicing the invention defined by the claims appended to this
specification, the following specification and drawings describe in
detail only preferred embodiments of practicing the invention.
Since not all implementation details described below are necessary
to practice the invention as recited in the claims, it is intended
that the invention be limited only by the claims.
Mechanical System
[0026] FIGS. 1-5 depict an elliptical exercise apparatus 10 in
accordance with the invention including a frame 14, a left footpad
50 and a right footpad 51 for supporting a user's left and right
feet. Left and right linkage assemblies 22 and 23 for a linkage for
coupling the left and right footpads 50 and 51 to frame 14 and for
guiding the footpads in closed paths when the user's feet apply
forces to the footpads. As discussed below, each linkage assembly
22 and 23 includes actuators that respond to control signals by
adjusting length and height dimensions of the closed path its
corresponding footpad follows. Each linkage assembly also includes
a rotatable member, suitably a crank member 12 rotatably mounted on
a frame 14, having an angular position that is indicative of the
positions of the footpads within their closed paths. A control
system, including a control panel 24 mounted on frame 14, senses
the angular position of the rotatable member and, for each footpad,
senses the forces applied to the footpad and generates the control
signals for controlling the length and/or height dimensions of the
closed path as functions of the sensed angular position and forces.
The control system increases or decreases the length and height
dimensions of the closed path of a footpad when the user-applied
force on the footpad is outside a particular magnitude range while
the angular position of the rotatable member is within a particular
angular position range. Exercise apparatus 10 thus allows the user
to control stride height and length by controlling magnitudes of
the forces the user applies to the footpads as they pass though
particular sections of their closed paths.
[0027] Left linkage assembly 22 also includes a telescoping left
foot member 16 having an upper channel member 18 supporting left
footpad 50 and slidably engaging a lower channel member 20. Left
linkage assembly 22 further includes an adjustable length crank
assembly 26 pivotally coupling lower channel member 20 to crank
member 12, a left rocker arm 28 pivotally coupled to frame 14
through a bearing pin 30 and pivotally coupled to upper channel
member 18 through a bearing pin 32, a left linear actuator 34
attached to rocker arm 28, and a left drawbar 36 pivotally coupled
to crank member 12 and lower channel member 20 through bearing pin
26 and pivotally coupled to actuator 34 through a bearing pin 38.
An upper end of rocker arm 28 forms a handlebar 40.
[0028] Right linkage assembly 23 is generally similar to left
linkage assembly 22 and includes a telescoping right foot member 17
for supporting the right footpad 51, a right side actuator 35
similar to left side actuator 34.
[0029] In addition to the right and left linkage assemblies 22 and
23, the linkage also includes a regenerative brake 46 mounted
inside frame housing 48 and a crank member 12 connected through a
belt 44 to the regenerative brake's rotor that rotates with crank
member 12. Brake 46 provides an amount of resistance to crank
member rotation that is adjusted by a control signal from control
panel 24.
[0030] As shown in FIGS. 2A and 2B, left footpad 50, includes a set
of rollers 52 for rollably engaging upper channel member 18 and a
flexible hook member 54 for grasping an upright member 56 attached
to an upper channel member for limiting horizontal motion of
footpad 50 along upper channel member 18. A strain gauge 58 mounted
on hook member 54 supplies control panel 24 with an indicating
signal of magnitude that varies as hook member 54 flexes. Strain
gauge is 58 is biased so that its output signal magnitude is at a
maximum when a user forces footpad 50 to the most forward position
(toward rocker link 28) along channel member 18 allowed by hook
member 54 and is at a minimum when the user forces footpad 50 the
most rearward position (toward crank member 12) along channel
member 18 allowed by flexible hook member 54. The magnitude of the
output signal of strain gauge 58 is a measure of the horizontal
force a user applies to footpad 50. Footpad 50 flexes as the user
applies a downward force on the footpad, and another strain gauge
60, attached to the underside of footpad 50, provides control panel
24 with an output signal of magnitude that varies with the amount
by which footpad 50 flexes. Thus the output signal of strain gauge
60 is a measure of the magnitude of the downward-directed vertical
force a user applies to footpad 60. Flexible conductors (not shown)
convey the output signals of strain gauges 58 and 60 to control
panel 24. Right footpad 51 is similar to left footpad 50 and
includes similar strain gauges.
[0031] FIG. 4 depicts an example implementation of left side
adjustable crank assembly 26 as including a linear actuator 62
attached to crank member 12 for adjustably controlling a distance
between a crank rod 64 and the crank member's rotational axis 66.
Crank rod 64 is coupled through bearings to footpad lower member 20
and drawbar 36. Linear actuator 62 includes a stepper motor
controlled by signals from control panel 24 that are delivered to
the stepper motor through wires coupling control panel 24 to brush
contacts (not shown) on crank member 12. A similar adjustable crank
assembly, including a linear actuator 63 is mounted on the right
side of crank member 12 to form a portion of left side linkage
assembly 23 of FIG. 1.
[0032] FIG. 5 shows an alternative version of left crank assembly
26 including a linear actuator 68 pinned to crank member 12 for
adjustably rotating a lever arm 70 also rotatably pinned to crank
member 12, thereby to adjust the distance between crank rod 64
attached to level arm 70 and crank member rotational axis 66.
Linear actuator 68 includes a stepper motor controlled by signals
from control panel 24 that are delivered to the stepper motor
through wires coupling control panel 24 to brush contacts (not
shown) on crank member 12. A similar adjustable right crank
assembly mounted on the right side of crank member 12 forms a
portion of right side linkage assembly 23 of FIG. 1.
Elliptical Motion
[0033] A user standing on right footpad 50 applies forces to
footpad 50 and handlebar 40 that cause foot member 16 to follow an
elliptical path defined by linkage assembly 22 and cause handlebar
40 to oscillate about bearing pin 30. We refer to the length of the
elliptical path in the generally horizontal direction as the
"stride length" and refer to the length of the elliptical path in
the generally vertical direction as the "stride height". Actuators
34 and 62 of FIGS. 3 and 4 control the stride height and stride
length by adjusting the shape of the elliptical path. The left side
actuators 35 and 63 similarly control the stride length and stride
height of the elliptical path followed by left footpad 51.
[0034] The "crank radius", the distance between pin 64 and the
rotational axis 66 of crank member 12 controlled by actuator 62 of
FIG. 4, influences the both stride height and stride height; as the
crank radius increases, so too do stride height and stride length,
The "rocker radius", the distance between bearing pins 30 and 38
controlled by linear actuator 34 also influences stride height but
does not substantially influence stride height; as rocker radius
increases, stride length decreases.
[0035] FIGS. 6A-6D show four example elliptical paths 72A-72D
followed by a point on left footpad 50. In FIG. 6A, the crank
radius is relatively small and rocker radius is relatively long, so
both stride height and stride length of path 72A are small. In FIG.
6B, both crank radius and rocker radius are relatively large, so
both stride length and stride and stride of path 72B are larger
than in path 72A. In FIG. 6C, the rocker radius is relatively small
and the crank radius is relatively large, so the stride length of
path 72C is longer than in paths 72A and 72B and stride height is
as large as in path 72B. In FIG. 6D, both rocker radius and crank
radius are small, so stride length of path 72D is long, about the
same as for path 72B, but stride height is small, about the same as
in path 72A.
[0036] Thus the control system can adjust actuators 34 and 62 to
provide a stride length ranging from the short stride length of
path 72A to the long stride length of path 72C and to provide a
stride height ranging from the short stride height of path 72A to
the high stride height of path 72C. Although the crank radius
controlled by actuator 62 influences both stride height and stride
length, the control system can independently adjust stride height
and stride length. For example, to increase or decrease stride
length without affecting stride height, the control system can
signal actuator 34 to decrease or increase the rocker radius
without signaling actuator 62 to change crank radius. To increase
stride height without affecting stride length, the control system
can signal actuator 62 to increase the crank radius and can signal
actuator 34 to increase the rocker radius. The increase in crank
radius not only increases stride height, but also tends to increase
stride length, the control system can offset the increase in stride
length by appropriately increasing rocker radius so that there is
no net increase in stride length. Conversely, to decrease stride
height without affecting stride length, the control system can
signal actuator 62 to decrease the crank radius and signal actuator
34 to appropriately decrease the rocker radius.
[0037] As discussed below, when exercise apparatus 10 is in a
manual stride height or length adjustment mode, the control system
adjusts stride height or length in response to use-operated
pushbuttons mounted on control panel 24. When the exercise
apparatus 10 is in an automatic stride height or length adjustment
mode, the control system adjusts stride height or length in
response to forces the user applies to footpads 50 and 51 which are
sensed by strain gauges 58 and 60 of FIGS. 2A and 2B or by
alternative means described below.
Control System
[0038] FIG. 7 is a block diagram showing a control system for
exercise apparatus 10 of FIGS. 1-5 including a conventional
computer 110 residing within control panel 24 and an I/O interface
circuit 118 interfacing computer 100 to user input devices 112 and
display devices 114 mounted on control panel 24, and a network
adapter 116. User input devices 114 allow the user to input
commands to computer and may include, for example, pushbuttons,
control knobs, a keyboard and/or a touch screen. Display devices
114, which may include, for example, pushbutton lights, light
emitting diodes, alphanumeric display panels, and/or a video
monitor, allow computer 110 to present various kinds of information
to the user. Network adaptor 116, which may be wireless, allows
computer 110 to communicate with other computers via conventional
network and Internet protocol for uploading programs and
downloading or uploading data.
[0039] The control system also includes various sensor and control
devices coupled to computer 110 via I/O interface circuit. Right
side control devices and sensors 120 include actuators 35 and 63
and strain gauges 59 and 60. Left side control and sensor devices
122 include actuators 34 and 62 and strain gauges 58 and 60. Strain
gauges 58-61 produce signals H_FORCE_R, H_FORCE_L, VFORCE_R and
VFORCE_L, respectively, indicating the magnitudes of horizontal and
vertical forces the user applies to footpads 50 and 51.
[0040] Regenerative brake 46 includes a generator 126 coupled for
rotation with crank member 12 of FIGS. 1-4. Generator 126 generates
an output voltage across a variable resistor 128 that increases
with the generator's rotational velocity producing a current
through resistor 128. Resistor 128 dissipates in the form of heat
the rotational energy the user expends rotating generator 126.
Under control of computer 110, I/O interface 118 transmits a signal
RESISTANCE to resistor 128 that controls the electrical resistance
of resistor 128, thereby controlling the mechanical resistance
regenerative brake 46 provides to crank rotation. The voltage
across resistor 128 is proportional to the angular velocity of
crank rotation and is provided as a VELOCITY signal input to I/O
interface circuit 118, which includes an analog-to-digital
converter for converting the analog VELOCITY signal into digital
data input to computer 110 indicting rotational velocity.
[0041] An angular position sensor 126 mounted within frame housing
48 of FIG. 1 provides a POSITION signal to I/O interface 118
indicating the angular position of crank member 12. In some
embodiments of the invention, the VELOCITY signal may be omitted
since computer 110 can alternatively compute velocity from changes
in angular position indicated by the POSITION signal. Devices and
circuits capable of carrying out the interface functions of I/O
interface circuit 118 are well known to those of ordinary skill in
the art.
[0042] Under control of computer 110, I/O interface circuit 118
transmits control pulses to actuators 34, 35, 62 and 63 via the
following control signals. Each control signal pulse tells the
receiving actuator to increment or decrement its length by a unit
amount:
[0043] INC_CR_R to tell actuator 35 to increment right side crank
radius,
[0044] DEC_CR_R to tell actuator 35 to decrement right side crank
radius.
[0045] INC_RR_R to tell actuator 63 to increment right side rocker
radius,
[0046] DEC_RR_R to tell actuator 63 to decrement right side rocker
radius.
[0047] INC_CR_L to tell actuator 34 to increment left side crank
radius,
[0048] DEC_CR_L to tell actuator 34 to decrement left side crank
radius,
[0049] INC_RR_L to tell left actuator 62 to increment left side
rocker radius, and
[0050] DEC_RR_L to tell actuator 62 to decrement left side rocker
radius.
[0051] Actuators 34, 35, 62 and 63 include internal limit switches
to prevent computer 110 from signaling them to drive rocker radius
or crank radius beyond their maximum or minimum limits. During
system startup, computer 110 sends a sufficient number of pulses to
each actuator to ensure that crank radius is at a minimum and
rocker radius is at a maximum. Thereafter, computer 110 keeps track
of the number of increment and decrement pulses it sends to each
actuator in order to keep track of each crank and rocker radius.
Computer 110 maintains a lookup table in its memory that relates
crank and rocker radius to stride length and stride height.
Whenever computer 110 needs to increment or decrement stride height
or stride length, it uses the lookup table to determine the amount
by which it must increment or decrement rocker radius and/or crank
radius in order to achieve the desired change in stride height or
length.
Stride Length Adjustment
[0052] The user can command computer 110 to operate in either a
manual stride length adjustment mode wherein computer 110 and I/O
interface circuit 118 control right and left stride length as a
function of user input supplied via user input devices 112 or in an
automatic stride length adjustment mode in which computer 110 and
I/O interface circuit 118 automatically control right and left
stride length based on sensor output.
[0053] As shown in FIG. 8, the user input devices 112 on control
panel 24 may include, for example, separate lighted pushbuttons 130
and 131 enabling the user to select between manual and auto stride
length adjustment modes, with pushbutton 130 or 131 being
illuminated to indicate the current mode of operation. When in the
manual stride length adjustment mode, computer 110 signals I/O
interface circuit to increase or decrease stride length in response
to user input via separate pushbuttons 132 and 133 and a stride
length sensitivity knob 134 allows the user control the amount by
which computer 110 signals actuators 34, 35, 62 and/or 63 to
increase or decrease stride length each time the user presses
button 132 or 133.
[0054] In the automatic stride length adjustment mode, computer 112
adjusts left and right stride length in response to a combination
of information contained in the H_FORCE_R and H_FORCE_L output
signals of the right and left horizontal strain gauges 58-61 and
the POSITION output signal of angular position sensor 126 of FIG. 7
indicating the angular position of crank rod 64 of FIG. 1. As
discussed above, left drawbar link 36 of linkage mechanism 22 is
rotatably connected to crank member 12 via crank rod 64, and as
crank rod 64 rotates about the axis 66 of crank member 12, linkage
mechanism 22 causes right left member 36 and left footpad 50 to
oscillate back and forth through a horizontal distance controlled
by actuators 34 and 62.
[0055] FIG. 9 depicts the circular path of crank rod 64 about the
axis 66 of crank member 12. When crank rod 64 is at its maximum
forward position, left footpad 50 has reached its maximum forward
position, right footpad 51 has reached its maximum rearward
position, and the POSITION signal output of position sensor 126
indicates that crank rod 64 is at 0 degrees. Conversely, when crank
rod 64 reaches its maximum rearward position, left footpad 50
reaches its maximum rearward position, right footpad 51 reaches its
maximum forward position, and the POSITION signal output of
position sensor 126 indicates crank rod 64 is at 180 degrees.
[0056] A user rotates crank member 12 by shifting most of his or
her weight to left side footpad 50 while crank rod 64 is moving
counterclockwise from 90 to 270 degrees, and by shifting most of
his or her weight to right side footpad 51 when crank rod 64 is
moving counterclockwise from 270 to 90 degrees. The percentage of
the user's weight allocated to the right and left during each half
cycle of crank rotation controls the downward vertical forces the
user applies to footpads 50 and 51 and affects the rotational
velocity of crank member 12. Vertical stain gauges 60 and 61 sense
the vertical forces on the footpads. The user's leg muscles can
also apply forward and rearward directed horizontal forces to
footpads 50 and 51 that are sensed by left and right horizontal
strain gauges 58-61. The horizontal forces on footpads 50 and 51
also affect rotational velocity, but normally to a lesser extent
than the vertical forces.
[0057] In the automatic stride length adjustment mode, computer 110
automatically increases or decreases stride length by increasing or
decreasing the lengths of actuators 34, 35, 62 and 63 in response
to the H_FORCE_L and H_FORCE_R signals produced by horizontal
strain gauges 58 and 59 and the POSITION signal produced by
position sensor 126. We define the following horizontal forces as
being positive in the forward direction from the user's point of
view:
[0058] F.sub.HL: horizontal force on left footpad 50,
[0059] F.sub.HR: horizontal force on right footpad 51,
[0060] F.sub.HHT: a high horizontal threshold level force, and
[0061] F.sub.LHT: a low horizontal threshold level force,
[0062] Computer 110 stores parameters indicating the high and low
horizontal threshold forces F.sub.HHT and F.sub.LHT as user
adjustable constants in its memory. In the automatic stride length
adjustment mode, computer 110 signals interface circuit 118 to
carry out the following operations:
[0063] Increment left side stride length when F.sub.HL>F.sub.HHT
and crank rod 64 resides between 80 and 100 degrees,
[0064] Increment right side stride length when
F.sub.HR>F.sub.HHT and crank rod 64 resides between 260 and 280
degrees,
[0065] Decrement left side stride length when F.sub.HL<F.sub.LHT
and crank rod 64 resides between 80 and 100 degrees, and
[0066] Decrement right side stride length when
F.sub.HR<F.sub.LHT and crank rod 64 resides between 260 and 280
degrees.
[0067] When computer 110 follows the above rule, a user quickly
learns that sufficiently increasing or decreasing the horizontal
forces of a footpad when the footpad is at the top of its forward
stride will cause an increase or decrease in stride length.
Although the position ranges for crank rod 64 suggested above are
provided for illustrative purposes, those of skill in the art will
appreciate that in other embodiments of the invention, the computer
may employ position ranges that vary from those indicated above
when testing for the user's desire to increase or decrease stride
length.
[0068] FIG. 10 is a flow chart for a program executed by computer
110 when in the automatic stride length adjustment mode. Computer
110 initially iteratively samples the right horizontal force data
F.sub.HR and the POSITION data provided by interface circuit 18
(step 202) until it determines from the POSITION data that crank
rod 64 resides between 260-280 degrees (step 204). If the last
sampled value of right horizontal force data F.sub.HR exceeds the
high horizontal threshold level force F.sub.HHT (step 206),
computer 110 signals interface circuit 118 to increment the right
stride length (step 208). If the last sampled value of right
horizontal force data F.sub.HR is less than the low horizontal
threshold level force F.sub.LhT (step 210), computer 110 signals
interface circuit 118 to decrement the right stride length (step
212). After step 208 or 212, or after step 210 if the last sampled
value of right horizontal force data F.sub.HR is between the low
horizontal threshold level force F.sub.LHT and the high horizontal
level threshold force F.sub.HHT, computer 110 begins iteratively
sampling the left horizontal force data F.sub.HL and the POSITION
data supplied by interface critic 118 (step 214) until it
determines from the POSITION data that crank rod 64 resides between
80 and 100 degrees (step 216). If the last sampled value of left
horizontal force data F.sub.HL exceeds the high threshold level
force F.sub.HHT (step 218), computer 110 signals interface circuit
118 to increment the left stride length (step 220). If the last
sampled value of left horizontal force data F.sub.HL is less than
the low threshold level force F.sub.LHT (step 222), computer 110
signals interface circuit 118 to decrement the left stride length
(step 224). After step 220 or 224, or after step 222 if the last
sampled value of left horizontal force data F.sub.HL is between the
low horizontal threshold level force F.sub.LHT and the high
horizontal level threshold force F.sub.HHT, computer 110 returns to
step 202. Note that computer 110 increments or decrements right or
left stride length at most only once during each rotational cycle.
The amount by which computer 110 increases left or right stride
length at step 208 or 220 increases with the amount by which the
last sampled horizontal force F.sub.HR or F.sub.HL exceeds the high
threshold level F.sub.HL. Similarly, the amount by which computer
110 decreases left or right stride length at step 212 or 224
increases with the amount by which the low threshold level F.sub.HL
exceeds the last sampled horizontal force F.sub.HR or F.sub.HL.
[0069] Thus in the automatic stride length adjustment mode, the
user can maintain a constant stride right and left stride lengths
by keeping the horizontal forces on the left and right footpads 50
and 51 between the high and low horizontal threshold levels
F.sub.HHT and F.sub.LHT while the left or right footpad is near its
high point and moving forward, and can increase or decrease left or
right stride length by increasing or decreasing the horizontal
force on right or left footpad 50 or 17 above or below the high or
low threshold levels while the footpad is near its high point and
moving forward. The particular ranges of positions employed at
decision steps 204 and 216 are a matter of design choice and can
vary from those shown in FIG. 10. For example at step 204 computer
110 could determine whether crank rod 64 is within a range of
90-120 degrees and at step 216 computer 110 could determine whether
crank rod 64 is in a range of 270-300 degrees. In the automatic
stride length adjustment mode, the user can adjust the values of
the two threshold level force constants F.sub.LHT and F.sub.HHT up
or down using stride length sensitivity knob 134. Computer 110
displays the current stride height and length and the current
threshold levels F.sub.LHT and F.sub.HHT on display monitor 114. In
the preferred embodiment of the invention, right and left stride
paths, including their lengths and heights, are independently
adjustable, which is advantageous because users having
non-symmetric leg strengths sometimes prefer slightly differing
right and left strides. In other embodiments of the invention,
computer 110 automatically adjusts right and left stride height
and/or length concurrently so they are always similar. This could
be implemented, for example, by changing the algorithm of FIG. 10
so that at steps 208 and 220 both right and left stride lengths are
incremented and so that at steps 212 and 224 both right and left
stride lengths are decremented.
[0070] In the preferred embodiment of the invention, pushbuttons
and knobs 132-134 allow the user to control right and left stride
lengths concurrently when the computer is operating in the manual
stride adjustment mode so that they are always similar.
[0071] However additional pushbuttons can be provided on control
panel 24 to allow the user to independently increment and decrement
right and length stride length when computer 110 is operating in
the manual stride length adjustment mode.
Stride Height Adjustment
[0072] The user can also command computer 110 to operate in either
a manual stride height adjustment mode wherein the user directly
controls stride height via user input devices 112 or in an
automatic height length adjustment mode in which the computer
automatically controls stride height based on sensor input.
[0073] As shown in FIG. 8, the user input devices 112 on control
panel 24 may include, for example, separate lighted pushbuttons 135
and 136 enabling the user to select between manual and auto stride
height adjustment modes, with pushbutton 135 or 136 being
illuminated to indicate the current mode of operation. When in the
manual stride height adjustment mode, computer 110 signals I/O
interface circuit to increase or decrease stride height in response
to user input via separate pushbuttons 137 and 138 and a stride
height sensitivity knob 140 allows the user control the amount by
which computer 110 increases or decreases stride length each time
the user presses button 137 or 138. While the preferred embodiment
of the invention provides switches and knobs 130-140 for the
above-described user input functions, one of skill in the art will
appreciate that input devices 112 provided for these function are a
matter of design choice and can be implemented by any of a variety
of devices including, for example, keyboards, keypads, touch
screens, and the like.
[0074] In the automatic stride height adjustment mode, computer 112
adjusts left and right stride height in response to a combination
of information contained in the V_FORCE_R and V_FORCE_L output
signals of the right and left horizontal strain gauges 100 and 101
and the POSITION output signal of angular position sensor 126 of
FIG. 7. We define the following vertical forces on the footpads as
being positive in the upward direction and negative in the downward
direction from the user's point of view:
[0075] F.sub.VR: vertical force on right footpad 51,
[0076] F.sub.VL: vertical force on left footpad 50,
[0077] F.sub.HVT: a high vertical threshold level force, and
[0078] F.sub.LVT: a low vertical threshold level force.
[0079] Interface circuit 118 converts the V_FORCE_R and V_FORCE_L
output signals of the right and left horizontal strain gauges 100
and 101 into data representing the vertical forces F.sub.VR and
F.sub.VL the user applies the left and right footpads 50 and 51 and
permits computer 110 to read access that data. Computer 110 stores
the high and low vertical threshold forces F.sub.HVT and F.sub.LVT
as user adjustable constants in its memory.
[0080] Assuming upward directed vertical forces are positive, the
vertical forces F.sub.VR and F.sub.VL the user applies to the left
and right footpads 50 and 51 are negative (downward directed) and
vary as the user rotates crank member 12 by shifting his or her
weight from one footpad to the other during each rotation cycle.
When crank rod 64 resides between 90 and 100 degrees, most of the
user's weight will be on right footpad 51 but the user will
normally continue to apply a modest downward force on left footpad
50. However it is possible for the user to shift all or almost all
of his or her weight to right footpad 51 when crank rod 64 is
between 90 and 100 degrees thereby causing vertical force F.sub.VL
on left footpad 50 greater (less negative) than a small negative
threshold force F.sub.HVT. In the automatic stride height
adjustment mode, computer 118 increases left side stride height
when F.sub.VL is greater (less negative) than F.sub.HVT when crank
rod 64 is between 90 and 100 degrees. Thus the user can signal
computer 110 to increase left side stride height by removing most
of all of his or her weight from footpad 50 when crank rod 64 is
between 90 and 100 degrees. Similarly, computer 118 increases right
side stride height when F.sub.VL is greater (less negative) than
F.sub.HVT when crank rod 64 is between 270 and 280 degrees. Thus
the user can signal computer 110 to increase left side stride
height by removing most of all of his or her weight from footpad 51
when crank rod 64 is between 270 and 280 degrees.
[0081] In the automatic stride height adjustment mode, computer 118
decreases left side stride height when F.sub.VR is less than (more
negative) than a low vertical threshold level F.sub.LVT when crank
rod 64 is between 90 and 100 degrees. Thus the user can signal
computer 110 to decrease left side stride height by shifting a
sufficient amount of all of his or her weight to left footpad 50
when crank rod 64 is between 90 and 100 degrees. Similarly,
computer 118 decreases right side stride height when F.sub.VK\L is
less (more negative) than F.sub.VT when crank rod 64 is between 270
and 280 degrees. Thus the user can signal computer 110 to decrease
right side stride height by a sufficient amount of his or her
weight to right footpad 51 when crank rod 64 resides between 270
and 280 degrees. In the automatic stride height adjustment mode,
the user can adjust the magnitude of low vertical threshold level
F.sub.LVT using stride height sensitive control knob 140 and
computer 110 signals interface circuit 118 to carry out the
following operations:
[0082] Increment left side stride height when F.sub.VL>F.sub.HVT
and crank rod 64 resides between 90 and 100 degrees,
[0083] Increment right side stride height when
F.sub.VR>F.sub.HVT and crank rod 64 resides between 270 and 280
degrees,
[0084] Decrement left side stride height when F.sub.VL<F.sub.LVT
and crank rod 64 resides between 90-100 degrees, and
[0085] Decrement right side stride height when
F.sub.VR<F.sub.LVT and crank rod 64 resides between 270 and 280
degrees.
[0086] The position ranges for crank rod 64 discussed above are
provided for illustrative purposes. Those of skill in the art will
appreciate that in other embodiments of the invention, the computer
may employ position ranges that vary from those indicated above
when testing for the user's desire to increase or decrease stride
height and the user will learn to apply the appropriate vertical
forces to the footpad at the appropriate points along their paths
as needed to initiate desired changes in stride height.
[0087] FIG. 11 is a flow chart for a program executed by computer
110 when in the automatic stride height adjustment mode. Computer
110 initially iteratively samples the right and left vertical force
data F.sub.VR and F.sub.VL and the POSITION data provided by
interface circuit 18 (step 302) until it determines from the
POSITION data that crank rod 64 resides between 270 and 280 degrees
(step 304). If the last sampled value of right vertical force data
F.sub.VR exceeds the positive high threshold level force F.sub.HVT
(step 306), computer 110 signals interface circuit 118 to increment
the right stride height (step 308). If the last sampled value of
left vertical force data F.sub.VL exceeds low threshold level force
F.sub.LVT (step 310), computer 110 signals interface circuit 118 to
decrement the left stride height (step 312). After step 308 or 312,
or after step 310 if results of both steps 306 and 310 are "NO",
computer 110 resumes iteratively sampling the right and left
vertical force data F.sub.VR and F.sub.VL and the POSITION data
(step 314) until it determines from the POSITION data that crank
rod 64 resides between 260 and 280 degrees (step 316). If the last
sampled value of left vertical force data F.sub.VL exceeds the high
threshold level force F.sub.HVT (step 318), computer 110 signals
interface circuit 118 to increment the left stride height (step
320). If the last sampled value of left vertical force data
F.sub.HL exceeds the low threshold level force F.sub.LVT (step
322), computer 110 signals interface circuit 118 to decrement the
left stride height (step 324). After step 320 or 324 or after step
322 if the result of both steps 318 and 322 is "NO", computer 110
returns to step 302. Note that computer 110 increments or
decrements right or left stride height at most only once during
each rotational cycle. The amount by which computer 110 increases
or decreases left or right stride height at step 308, 312, 320 or
324 increases with the amount by which the last sampled vertical
force F.sub.HR or F.sub.HL exceeds the high or low threshold level
F.sub.VHT or F.sub.VHT.
[0088] Thus in the automatic stride height adjustment mode, the
user can maintain a constant right and left stride height by
keeping the vertical forces on the right and left footpads 50 and
51 between the high or low threshold levels F.sub.VHT or F.sub.VHT
while the footpads are approaching their high points. The user can
increase right or left stride height by lifting his right or left
foot off the right or left footpad 50 or 17 as it nears its high
point and can decrease right or left stride height by pushing down
sufficiently hard on the right or left footpad 50 or 17 as it nears
its high point.
[0089] In the preferred embodiment of the invention, right and left
stride height are independently adjustable in the automatic mode,
which is advantageous because users having non-symmetric legs
sometimes prefer slightly differing right and left stride heights.
In other embodiments of the invention, computer 110 can
automatically adjust right and left stride height concurrently so
they are always similar. This could be implemented, for example, by
changing the algorithm of FIG. 10 so that at steps 308 and 320 both
right and left stride heights are incremented and so that at steps
312 and 324 both right and left stride heights are decremented.
[0090] In the preferred embodiment of the invention, pushbuttons
and knobs 137-140 allow the user to control right and left stride
height concurrently when the computer is operating in the manual
stride adjustment mode so that they are always similar. However
additional pushbuttons can be provided on control panel 24 to allow
the user to signal computer 110 to independently increment and
decrement right and stride height when computer 110 is operating in
the manual stride height adjustment mode.
[0091] Those of skill in the art will also appreciate that the
particular ranges of positions employed at decision steps 304 and
316 are a matter of design choice and can vary from that shown in
FIG. 10. For example at step 304 computer 110 could determine
whether crank rod 64 is within a range of 90-120 degrees and at
step 316 computer 110 could determine whether crank rod 64 is in a
range of 270-300 degrees.
[0092] Stride Length Control Based on Angular Velocity and
Position
[0093] In the automatic stride length control mode, computer 110
determines when to increase or decrease stride length base as a
function of the POSITION signal output of angular position sensor
126 and of the H_FORCE_R and H_FORCE_L output signals of horizontal
strain gauges 59 and 60. In an alternative embodiment of the
invention, computer 110 determines when to change stride length as
a function of the POSITION signal and the VELOCITY signal output of
regenerative brake 46, thereby eliminating the need for horizontal
strain gauges 59 and 60. This is particularly advantageous in an
exercise apparatus that does not provide automatic stride height
control mode and therefore does not require vertical strain gauges
60 and 61. Eliminating the need for all strain gauges 98-101
reduces the complexity of footpads 50 and 51 and allows them to be
formed as integral parts of foot members 16 and 17 and the wiring
needed to deliver the strain gauge output signals to control panel
24 can be eliminated.
[0094] FIG. 12 plots the magnitude V of the VELOCITY signal as a
function of both time and crank position as the user moves footpads
50 and 51 through a full rotation cycle of crank member 12 as
indicated by the POSITION signal output of angular position sensor
128. FIG. 13 plots the acceleration A of crank member 12 as a
function the angular position of crank rod 64. FIG. 12 also
graphically depicts at angular positions 0, 270, 180 and 90 degree
positions of crank rod 64 of FIG. 1 as it rotates about crank axis
66 as indicated by the POSITION signal and shows the direction of
the horizontal and vertical forces on crank. crank resulting from
user forces applied to the footpads.
[0095] At 0 degrees, the user applies the majority of his or her
weight on footpad 50 to apply a net downward force F.sub.VL on
crank rod 64 which accelerates crank rotation by overcoming
resistive forces applied by regenerative brake 46. Since at 0
degrees, crank rod 64 is at its maximum horizontal distance from
crank axis 66 of cranks 20 the net vertical force F.sub.VL on crank
rod 64 maximally accelerates crank member 12 as indicated by the
rapidly increasing magnitude V of the VELOCITY signal at the 0
degree position. As crank rod 64 approaches 270 degrees, crank
acceleration declines due to the decreasing leverage afforded by
the declining horizontal distance between crank rod 64 and crank
axis 66 and because the user has begin shifting his or her weight
between footpads 50 and 51 so that the forces on left crank rode 64
and its right crank rod counter part 65 tend to cancel one another
with respect to accelerating crank member 12. Angular velocity
peaks at about 315 degrees when the rotational forces provided by
the user fall below the resistive forces provided by regenerative
brake 14. As crank rod 64 reaches its 270 degree position, the
vertical forces on crank rods 64 and 65 have no effect on
acceleration and crank deceleration is at a maximum, as indicated
by the large negative slope of VELOCITY signal magnitude V.
Velocity continues to decline to a minimum when crank rod 64
reaches its 225 degree position. Maximum rotational acceleration is
again achieved when crank rod 64 reaches 180 degrees due to the
large net vertical force on pin 45 at a maximum horizontal distance
from crank axis 66.
[0096] FIG. 12 plots angular velocity V and acceleration of crank
rod 64 of FIG. 1 as a function of the angular position of crank rod
64 during one cycle of pin rotation and also graphically depicts
the net vertical forces F.sub.VR and F.sub.VL the user applies to
pins 64 and 65 4 and the horizontal forces F.sub.HR and F.sub.HL
the user applies to points 44 and 45. FIG. 12 is drawn with the
assumption that the user is maintaining a steady pace and that
F.sub.HL and F.sub.HR are zero because the user is applying no
horizontal forces to footpads 50 and 51.
[0097] Even when the user pedals at a constant rate to provide a
constant average angular velocity, the instantaneous angular
velocity V will vary as shown in FIG. 12 during each cycle of
rotation. At the 0 and 180-degree positions, acceleration A is at
its positive maximum positive because F.sub.V, being maximally
horizontally displaced from crank member axis 66, rapidly
accelerates the crank. At the 90 and 270 degree positions,
acceleration is at its negative minimum because F.sub.V, having no
horizontal displacement from crank member axis 66, has no effect on
crank acceleration and the crank rapidly decelerates due to the
resistive force on crank member 12 provided by brake 46. The "net
vertical force" F.sub.V is defined as the difference between the
vertical forces F.sub.VR and F.sub.VL via crank rods 64 and 65 and
is directed at the point receiving the larger of the two forces
[0098] The user could increase his or her pace by increasing the
net force F.sub.V applied to applied to crank rods 64 and 64, and
in such case, both the velocity and acceleration curves of FIG. 12
would trend upward until the resistance provided by regenerative
brake 46, which increases with rotational velocity, balances the
increased cranking force provided by the user. At that point the
velocity curve would look similar to that of FIG. 12, but would be
shifted upward.
[0099] Acceleration A at any given position P of crank rod 64 is a
function of the net vertical force F.sub.V on the crank rods 64 and
65 applied via lifter links 70 and 71 of FIG. 1, the net horizontal
forces F.sub.H on crank rods 64 and 65 and the resistive force
F.sub.R provided by regenerative brake 46, and the angular position
P of crank rod 64.
A=f(F.sub.V,F.sub.HR,F.sub.HL,F.sub.R,P)
[0100] The resistive force F.sub.R provided by regenerative brake
46 is a function of the rotational velocity V of the crank member
12 and the magnitude of the resistance R of resistor 128 of FIG. 7.
Thus
A=g(F.sub.V,F.sub.HR,F.sub.HL,V,R,P)
[0101] When the user applies no horizontal forces F.sub.HL,
F.sub.HR to footpads 50 and 51, then the negative crank
acceleration at the 270 degree position of crank rod 64 arises only
from resistive force F.sub.R due to V and R because the net
vertical force F.sub.V is zero when P=270 degrees. Thus the
expected acceleration A at the 270 degree position when net
horizontal forces are 0,
A=g(0,0,0,V,R,270)
[0102] We define a variable A.sub.E270 as an "expected" crank
acceleration for a given velocity at the 270 degree pin position
when horizontal forces F.sub.HL, F.sub.HR on crank rods 64 and 65
are zero. The expected 270 degree position crank acceleration
A.sub.E270 is a function only of V and R.
A.sub.E270=h(V,R)
[0103] The expected acceleration A.sub.E90 at the 90-degree
position of crank rod 64 is a similar function of V and R when
horizontal forces on crank rods 64 and 65 are zero.
A.sub.E90=h(V,R)
[0104] During each crank cycle, computer 110 samples the POSITION
and VELOCITY signals to determine the magnitude V of crank velocity
whenever the POSITION signal indicates crank rod 64 is at either
the 90 or 270 degree position. Knowing the value to which it most
recently set resistance R, computer 110 then computes A.sub.E90 and
A.sub.E270 based on a stored equation or lookup table model of the
above function h(V,R). The function is experimentally determined at
the factory at the time the exercise apparatus is built and then
stored in non-volatile memory of computer 110.
Stride Height and Length Control for Backward Mode Operation.
[0105] Referring to FIG. 1, when the user operates exercise
apparatus 10 in a "forward mode" as described above such that crank
rod 64 rotates counter-clockwise about the axis of crank member 12
as viewed from the left side of the apparatus, the user's feet will
move in much the same way as the would if the user were walking
forward on a flat surface. However the user can alternatively
operate exercise apparatus 10 in a "backward mode" by rotating
crank rod 64 in a clock-wise direction, thereby moving his or her
feet in a manner similar to walking backwards. Computer 110
determines whether the user is operating the apparatus in the
forward or backward mode based on how the POSITION signal output of
angular position sensor 126 changes with time. During backward mode
operation, when the user has selected automatic stride height
and/or length control, computer 110 automatically adjusts stride
height and/or length based on user applied forces using algorithms
substantially similar to the forward walking mode algorithms
described above, except that the angular positions at which user
forces are sensed differ in the reverse mode. In the backward mode
computer 110 will carry out the following actions:
[0106] Increment left side stride height when F.sub.VL>F.sub.HVT
and crank rod 64 resides between 80 and 90 degrees,
[0107] Increment right side stride height when
F.sub.VR>F.sub.HVT and crank rod 64 resides between 280 and 10
degrees,
[0108] Decrement left side stride height when F.sub.VL<F.sub.LVT
and crank rod 64 resides between 80 and 90 degrees, and
[0109] Decrement right side stride height when
F.sub.VR<F.sub.LVT and crank rod 64 resides between 280 and 10
degrees.
Interface Circuit
[0110] Interface circuit 118 and computer 110 determine the "actual
crank accelerations" A.sub.A90 and A.sub.E270 at crank rod 64
positions 90 and 270 by differentiating the VELOCITY signal and
sampling the result whenever the POSITION signal indicates crank
rod 64 is at either the 90 or 270 degree position. FIG. 13 depicts
a circuit within interface circuit 118 for providing computer 110
with data V90, V270 representing rotational velocity at the 90 and
270 degree positions, data AA90 and AA270 representing actual
acceleration at the 90 and 270 degree positions, and a data
sequence V representing instantaneous rotational velocity. A
digitizer 340 digitizes the VELOCITY signal many times during each
rotational cycle in response to a CLOCK signal to produce the V
data sequence. A differentiating amplifier 350 differentiates the
VELOCITY signal and a digitizer 352 also clocked by the CLOCK
signal, digitizes the result to produce another data sequence
representing the angular crank acceleration A. Position detector
356 checks the POSITION signal on each pulse of the CLOCK,
supplying an interrupt signal INT.sub.90 to computer 110 whenever
crank rod 64 is at the 90 degree position and supplying an
interrupt signal INT.sub.270 to computer 110 whenever crank rod 64
is at the 270 degree position. An OR gate 380 Ors the INT.sub.90
and INT.sub.270 signals to produce a signal for clocking a pair of
registers 342 and 354 for storing the V and A outputs of digitizers
340 and 352, respectively. Interrupt signals INT.sub.90 and
INT.sub.270 tell computer 110 to read the contents of registers 342
and 354. When INT.sub.90 is asserted, computer 110 assumes the
contents of registers 342 and 354 are V.sub.90 and A.sub.A90, and
when INT.sub.270 is asserted, computer 110 assumes the contents of
registers 342 and 354 are V.sub.270 and A.sub.270. Since those of
skill in the art will appreciate that there are many other possible
ways to carry out the function of the circuit of FIG. 13 and that
the approach used is a matter of design choice.
[0111] The difference between the expected and actual accelerations
at the 90 and 270-degree positions of crank rod 64 is a function of
the amount and direction of net horizontal force F.sub.H the user
is applying to pins.
F.sub.H90=m(A.sub.A90-A.sub.E90)
F.sub.H270=m(A.sub.A270-A.sub.E270)
The constant m is the mass of the system the horizontal forces
F.sub.HR and F.sub.HL must move when accelerating the crank at the
90 and 270-degree positions.
[0112] In the alternative embodiment of the invention, computer 110
determines (A.sub.A90-A.sub.E90) and (A.sub.A270-A.sub.E270) each
time crank rod 64 arrives at it 90 or 270 degree position, and
determines whether to increase or decrease stride length depending
on the magnitude of the difference. When (A.sub.A90-A.sub.E90) or
(A.sub.A270-A.sub.E270) is larger than a high threshold value,
computer 110 increases both right and left side stride length. When
(A.sub.A90-A.sub.E90) or (A.sub.A270-A.sub.E270) is less than a low
threshold value, computer 110 decreases both right and left side
stride length.
[0113] Referring to FIGS. 1 and 2, note that the user can also
apply horizontal forces to crank rods 64 and 65 through linkages 22
and 23 by pushing and pulling on handle bars 40 and 41. Since in
the alternative embodiment of the invention stride length is
adjusted in response to horizontal forces on crank rod 64
regardless of whether they originate from user forces applied to
pads 16 or 17 to hand grips 40 and 41, the user can increase or
decrease stride length by increasing or decreasing forces he or she
applies to hand grips 40 and 41 when crank rod 64 is at the 90 or
270 degree position.
Resistance Control
[0114] Referring to FIGS. 1, 7 and 8, control panel 24 includes a
pair of pushbuttons 142 and 142 enabling the user to command
computer 110 to increase or decrease the resistance to rotation of
cranks 121 and 122 provided by regenerative brake 46 by signaling
I/O interface circuit 118 to increase or decrease the resistance of
resistor 128. Display devices 114 of FIG. 7 include a numeric
display panel 143 for indicating the current resistance level.
Programmed Exercise
[0115] Computer 110 can operate in a "Program Mode" in which it
automatically varies the resistance of brake 46, stride length,
and/or stride height at various times during exercise. Referring to
FIG. 8, the user presses either of a pair of pushbuttons 142 on
control panel 24 to tell computer 110 whether it is to turn the
program mode on or off.
[0116] Referring to FIGS. 7 and 8, display devices 114 and user
input devices 112 within control panel 24 include in addition to
control buttons and knobs 142 include a display monitor 141 for
presenting data and other displays under control of computer 110.
Display monitor 141 includes a conventional touchscreen for
signaling computer 110 whenever the user has touched the surface of
the display monitor and for indicating the area of the monitor the
user has touched. Computer 110 displays push button icons and menu
items the user can touch to provide input commands to computer 110.
In the program mode, computer 110 generates a video of terrain on
monitor 141 to simulate what the user might see if the user were
running in such a terrain and also changes resistance, stride
length, and/or stride height to simulate the effects of changes in
the slope of the terrain viewed on display monitor 141. For
example, resistance and stride height are increased and stride
length is decreased when the display shows the user is traveling
uphill while resistance and stride height are decreased and stride
length is increased when the display shows the user is traveling
downhill. Network adapter 116 suitably allows computer 110 to
download various programs via the Internet in response to commands
from the user via the touchscreen monitor 141. The user selects
from among stored exercise programs listed as menu items on display
monitor by using the touchscreen to select the appropriate menu
item.
[0117] Computer 110 can use the touchscreen of monitor 141 to
receive user input allowing the user, for example, to [0118] (a)
Log in as a user or log out [0119] (b) Select exercise parameters
being displayed. [0120] (c) Select an exercise program, [0121] (d)
Download a new exercise program.
[0122] Computer 110 also uses display monitor 141 to display a
variety of data regarding user exercise in graphical or numeric
form including, but not limited to: [0123] (a) Current resistance
level, [0124] (b) Elapsed exercise time, [0125] (c) Current speed
of exercise, [0126] (d) Average speed of exercise, [0127] (e)
Number of calories burned during exercise [0128] (f) Simulated
distance traveled during exercise [0129] (g) Simulated elevation
gains and losses during exercise, [0130] (h) User's weight, [0131]
(j) Available exercise programs, [0132] (k) Currently selected
exercise program, [0133] (l) Current stride height and length
[0134] (m) Historical exercise data for each user.
[0135] Those of skill in the art will appreciate that computer 110
can be programmed to determine and display exercise speed, calories
burned, distance traveled, and user weight from information
provided by I/O interface 118 in response to signals it receives
representing forces on the footpads, rotational velocity and
position. Stride height, stride length and resistance are directly
controlled by computer 110 and therefore known the computer.
Historical exercise data for each user which may be displayed in
tabular or graphical form, can include, for example, daily number
of calories burned, distances traveled, exercise programs completed
and times required to complete them.
[0136] The present invention has been described with the
understanding that persons skilled in the art will recognize
additional embodiments, improvements, and/or applications that
nonetheless fall within the scope of the invention. For example,
while the invention has been illustrated in connection with an
elliptical exercise machine having a particular type of linkage for
coupling each footpad to the frame and for controlling the path
that the footpad follows, the invention in its broadest sense can
be practiced in connection with exercise with any kind of linkage
that can respond to input signals by adjusting one or more
dimensions of that path. Therefore, the scope of the present
invention as defined in any one the claims appended hereto is not
intended to be limited to the particular linkage described in the
specification and drawings except to the extent the claim recites
details of such linkage. Also while the drawings and specification
have described alternative methods and apparatuses for monitoring
user forces on the footpad, including the use of strain gauges on
the foot pad and processing the angular velocity signal to
determine crank member acceleration, those of skill in the art will
appreciate that the invention can be practiced using other methods
and apparatuses for monitoring those forces. Therefore, the scope
of the present invention as defined in any one of the claims
appended hereto is not intended to be limited to any particular
method of monitoring such forces described in the specification and
drawings except to the extent that the claim may recite details of
such method or apparatus. Those of skill in the art will also
appreciate that any of a variety of methods and apparatuses for
sensing the angular position of a rotatable member are known in the
art and could be employed for that purpose when practicing the
invention. Therefore, the scope of the present invention as recited
in any one of the claims appended hereto is not intended to be
limited to any particular method for sensing forces described in
the specification and drawings except to the extent the claim may
recite specific details of such method or apparatus. While the
invention has been illustrated as being used in an elliptical
exercise machine that guides a user's feet in an elliptical type of
closed path, the principles of the invention can be used to
automatically control path dimensions in other exercise machines
such as, for example, steppers, gliders, skiers and climbers, that
guide a user's feet in other types of closed paths including, for
example, linear and/or arcuate paths that can be adjusted in one or
more dimension.
* * * * *