U.S. patent application number 14/603283 was filed with the patent office on 2016-07-28 for intelligent treadmill and enhancements to standard treadmills.
The applicant listed for this patent is Jackson Ping-kuen Chack, Albert Ting-pat So, Kin Wa Yee. Invention is credited to Jackson Ping-kuen Chack, Albert Ting-pat So, Kin Wa Yee.
Application Number | 20160213976 14/603283 |
Document ID | / |
Family ID | 56433047 |
Filed Date | 2016-07-28 |
United States Patent
Application |
20160213976 |
Kind Code |
A1 |
So; Albert Ting-pat ; et
al. |
July 28, 2016 |
Intelligent Treadmill and Enhancements to Standard Treadmills
Abstract
An intelligent treadmill is described with modifications to
existing treadmills, and associated methodology. The invention
allows the conveyor belt automatically keeps track of and fixes the
user's position dynamically with respect to a stationery reference
point of the treadmill by adjusting its own speed free hands. Two
position measurement techniques and their corresponding belt speed
control algorithms are described. Other features of the invention
allow users to perceive in real time how their surroundings would
be changing by means of video, incline of platform, fan speed,
sound and illumination as if they were in fact running in the
natural environment. Real time positions of the runner and his
partners on other treadmills with respect to a chosen track are
displayed. The invention also utilizes a vectored controlled
2/3-phase AC induction motor or a BLDC motor to drive the conveyor
belt for energy efficiency and fast response.
Inventors: |
So; Albert Ting-pat;
(Bothell, WA) ; Chack; Jackson Ping-kuen; (Hong
Kong, HK) ; Yee; Kin Wa; (Hong Kong, HK) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
So; Albert Ting-pat
Chack; Jackson Ping-kuen
Yee; Kin Wa |
Bothell
Hong Kong
Hong Kong |
WA |
US
HK
HK |
|
|
Family ID: |
56433047 |
Appl. No.: |
14/603283 |
Filed: |
January 22, 2015 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A63B 2220/805 20130101;
A63B 71/0622 20130101; A63B 2071/0638 20130101; A63B 2225/20
20130101; A63B 2071/0683 20130101; A63B 22/0242 20130101; A63B
22/025 20151001; A63B 2220/13 20130101; A63B 2225/50 20130101; A63B
24/0087 20130101; A63B 2071/0081 20130101; A63B 2024/0093 20130101;
A63B 2024/009 20130101; A63B 2220/20 20130101; A63B 2225/105
20130101; A63B 2071/0625 20130101; A63B 22/0023 20130101; A63B
2225/74 20200801 |
International
Class: |
A63B 24/00 20060101
A63B024/00 |
Claims
1. An intelligent treadmill allowing the conveyor belt
automatically keeps track of and fixes the runner position
dynamically with respect to a stationary reference point of the
treadmill by adjusting its own speed free hands based on speed
varying algorithms, the said intelligent treadmill comprising: a
touch screen monitor, transmitter/receiver, motor, electronic
drive, control panel, reflector and three pairs of poles, the said
touch screen monitor equipped with a pair of loudspeakers and lamp,
displaying the video of the surrounding environment of an outdoor
track, downloaded from the Internet and a simple map showing
current position of runner, the said receiver for distance
measurement emitting and receiving a laser beam to help estimate
the exact distance of the reflector on the said runner away from
it, the said motor which is a vectored controlled pulse width
modulation based two or three phase alternating current or
brushless direct current motor to adjust the speed of the conveyor
belt to fix the said runner at a more or less constant distance
from the transmitter/receiver or at a dynamically stable and
stationary position on the moving belt, the said motor which is
energized by an electronic drive which gets power from a standard
single phase supply, the said control panel which controls the
speed of the treadmill and has additional control to adjust the
speed of the conveyor belt to fix the said runner at a more or less
constant distance from the transmitter/receiver or at a dynamically
stable and stationary position on the belt, the said reflector worn
on the waist belt of the said runner for reflecting the laser beam
from the said transmitter/receiver, the said three pairs of poles
installed on both sides of the platform of the said treadmill
equipped with laser based transmitters, receivers and
reflectors.
2. The intelligent treadmill of claim 1 wherein said means for
measuring instantaneous position of the said runner of the said
treadmill comprise a laser based transmitter and receiver installed
at an appropriate position of the said treadmill, and a reflector
worn on the body of the said runner.
3. An intelligent treadmill of claim 1 wherein said means for
measuring instantaneous position of the said runner comprise
several pairs of poles installed on both sides of the said platform
of the said treadmill at appropriate positions, equipped with laser
based transmitters, receivers and reflectors for detecting the
existence of any obstacle between two corresponding said poles.
4. An intelligent treadmill of claim 2 wherein said a speed varying
algorithm of the conveyor belt of the said treadmill based on the
said position of said runner measured of claim 2 is according to a
set of differential equations with tuned gains, K.sub.I and
K.sub.P, for automatically and dynamically fixing the said position
of said runner at a desirable position on the moving belt with
reference to a stationary point of the said treadmill.
5. An intelligent treadmill of claim 3 wherein said a speed varying
algorithm of the conveyor belt of the said treadmill based on the
said position of said runner measured of claim 3 is according to a
set of differential equations with tuned gains, K.sub.I, C.sub.1
and C.sub.2, for automatically and dynamically fixing the said
position of said runner at a desirable position on the moving belt
with reference to a stationary point of the said treadmill.
6. An intelligent treadmill of claim 3 and claim 4 wherein an
emergency stopping procedure stops the moving belt when either the
said position of claim 3 or the said position of claim 4 exceeds a
safety limit.
7. An intelligent treadmill of claim 1 wherein said means for
keeping track of the instantaneous position of the said runner with
respect to the said outdoor track for synchronization of the video
display and environmental background controls, means for
continuously updating the said position of the said runner along
the said track based on the said speed of the conveyor belt for
displaying the corresponding scene of the surrounding environment
of the said track, the said position of the runner on a map of the
said track and parameters on the said monitor, and means for
providing environmental background control at the local said
treadmill including incline of said platform, music and sound,
speed of circulating fan on a control panel of the said treadmill,
and the level of illumination, are provided.
8. An intelligent treadmill of claim 1 wherein said means for
intercommunicating the instantaneous positions of said runners on
different said treadmills using the same outdoor track for
displaying the updated positions of all said runners on the said
monitors, allowing a group of said runners running on their
corresponding said treadmills, exchanging instantaneous positions
of said runners, and displaying positions of all said runners of
the said group on the map of common said outdoor track on all said
monitors.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Application No. 61/966,247 filed Feb. 20, 2014, which is
incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a device for walking or
running while staying in the same place, commonly referred to a
treadmill, enhancements and adaptations to existing treadmills, and
associated methodology. Specifically, the treadmill aspect of the
invention involves a modification to conventional drives found in
domestic applications, a position sensing device, a speed
controlling algorithm to dynamically fix the user or runner at the
same position and a virtual environment to aid walking and running
with Internet based social communication. In this document, the
terms "user" and "runner" share the same meaning, i.e. the human
body moving on the moving belt of the treadmill.
BACKGROUND OF THE INVENTION
[0003] Treadmills are popular exercise machines for running or
walking in one place, usually indoors, including the home, school,
fitness center, or even office. The basic treadmill provides an
adjustable slanting platform on which a wide conveyor belt is
running; the belt is driven by an electric motor through a sheave,
usually Direct Current (DC) typed for home treadmills, with a
rating from 1.5 to 4 horsepowers. Commercially graded treadmills
used in gyms may employ Alternating Current (AC) motors. The
conveyor belt moves in a way requiring the runner to walk or run at
a speed matching that of the belt, which is usually adjustable but
fixed. Here, "fixed" means that the speed is either constant or
undergoes a continuous acceleration or deceleration over a short
period of time until the speed becomes constant. This is the
operation of common treadmills. The "fixed" rate at which the belt
moves can be controlled by the runner on a control panel to a
continuous rate from a slow walk or to a run, which is displayed on
the control panel.
[0004] Most treadmills have at least the following standard
functions: (1) controllable but constant speed of movement of the
belt; (2) inclined setting allowing for consistent "uphill"
training; (3) features to measure and display the heartbeat of the
user; (4) preinstalled programs for simulating various exercise
routines; (5) measurement of distance run by the runner, estimation
of calories burned, and other performance measurements such as
average speed; (6) audio and/or visual input or output allowing
runners to listen to music from an audio device or audio-visual
device, or both; (7) monitors allowing the user to view television,
movies, or other visual materials; (8) a fan to blow air over the
runner for cooling or to provide as if the runner were not standing
still; and (9) a mechanism to stop the machine under emergency
conditions when the runner moves to a rear position of the belt
considered too unsafe for operation, such as a magnetic detector
linked to the runner via a piece of string with a clip on the
runner's cloth.
[0005] Having introduced the standard functions of conventional
treadmills, we now turn to how conventional treadmills generally
function and the problems with the standard design. One purpose of
a treadmill is to allow for exercise via running or walking inside
and in one place. One advantage of a treadmill over other exercise
machines is the freedom of movement: it allows users walk or run as
if they were not walking or running in place. In other words,
treadmills allow users to walk or run in their natural strides, at
the natural height in which they pick their feet up off the ground,
move their hands freely as if they were not standing in place, and
other movements which other exercise machines restrict. Even though
this freedom of movement aspect is realistic in the sense runners
would do the same if they were not standing in place, other
features of how conventional treadmills shape the user experience
are unrealistic.
[0006] One important unrealistic aspect of treadmills is due to the
operation of treadmills in terms of the constant speed setting.
Users adjust the speed of the conveyor belt manually, i.e., to
change the speed users must consciously utilize an interface to
adjust it. Once a new speed is set, the belt accelerates or
decelerates gradually for a short period of time until the new
speed of the belt is achieved. The constant speed operation imposes
a strict pace on runners, perhaps giving an unnatural feel to
running which can cause a runner to loose balance and feel
discomfort. How the speed on standard treadmills is controlled is
unrealistic because human beings do not naturally run under a
constant speed; rather, people naturally move faster and slower
slightly over time but usually the overall average speed, say in
one hour, is almost constant. However, during normal operation,
treadmills prevent the runner to adjust even small changes in
speed, unless with the runner's conscious attention to key in a
command on the control panel. In this regard, although speed
control by the runner is relatively easy and straight forward,
merely by requiring conscious effort to change speed even slightly
does not always offer the psychological satisfaction that runners
get from running outdoors or anywhere where speed control does not
have to be a conscious effort.
[0007] A second important unrealistic aspect of treadmills is
perhaps due to the problem treadmills attempted to solve in the
first place: walking or running outdoor or indoor is unavailable.
However, many treadmill users today use treadmills because of
convenience--i.e., even when walking or running outside or
somewhere inside is available. Nonetheless, the user experience of
conventional treadmills is unrealistic compared with walking or
running not-in-place because the runner is, by definition, not
moving geographically and so the runner's surroundings are not
changing. This psychological consideration may at first seem
irrelevant because of the fact that the runner is indeed not moving
geographically, but despite the obviousness of not moving
geographically on a treadmill may take a toll on the runner's
motivation and mental wellbeing at least compared to walking or
running outdoor. One reason is that treadmill exercise does not
allow runners to unconsciously compare their progress in the walk
or run; instead, they must look to the treadmill's display of
distance or time to check their progress based on these figures
only. One could compare this to a runner who typically walks or
runs a number of routes and thus knows the remaining distance or
effort required to complete the desired exercise. The surrounding
environment in such a walk or run allows the walker or runner to
acquire mental estimation about the remaining distance, whereby the
walker or runner can unconsciously decipher the remaining
difference. This cannot happen on a treadmill. This psychological
consideration is yet another unrealistic aspect of conventional
treadmills. In a similar vein, standard treadmills are made for
individual users--e.g., the belt is not wide enough, or designed,
to allow two or more people walk or run on it together. Even if two
runners walk or run side by side on adjacent treadmills, the
feeling of companionship and support achieved from it is most
likely less than by walking or running side by side in a natural
environment as they know the pace of the other person. This
perception of relative pace setting and comparison is what is
lacking for treadmills, which perhaps can detract from one's
motivation to exercise.
[0008] Having introduced the standard functions, general
functioning, and a few unrealistic aspects of the standard
treadmill design, we will now discuss the standard power drive and
problems with it. Almost all existing home-use treadmills use DC
motors with a rated voltage from 12 V to around 130 V. From a
design standpoint, the speed and change in acceleration controls
for DC motors are straightforward. Although DC motors are efficient
at changing conveyor belt speeds, they are not energy efficient,
not for swift acceleration or deceleration, and tend to require
maintenance. Moreover, this technology is fading gradually in
related machines. Current ratings for most standard home treadmill
DC motors are below 4 (continuous) horsepowers (or about 3 kW) with
a peak rotating speed of around 4,000 r.p.m. Generally, DC motors
used for home treadmills are of the Permanent Magnet DC (PMDC)
typed. The permanent magnets are installed at the stator. The rotor
receives controlled DC current via commutators and brushes. The
loss at the contacts between brushes and commutators is high and
the optimal energy profile of DC motors cannot be controlled.
[0009] The present invention addresses the need to alleviate
problems in both conventional home and industrial treadmills
including: (a) the unrealistic constant speed aspect of standard
treadmills due to requiring users to consciously utilize an
interface to adjust even minor changes in speed; (b) the
unrealistic user experience aspect of standard treadmills in that
(i) because the user's surroundings are not changing (and, when
users are exercising with one or more other people, not changing
together in real time), users must consciously check their progress
in the walk or run by viewing the display of distance or time
instead of unconsciously knowing the percentage of the exercise
completed or remaining; (ii) an unchanging user environment is not
as mentally and emotionally stimulating as a changing environment;
and (c) the relatively outdated and energy inefficient technology
used to drive the conveyor belt for home treadmills.
SUMMARY OF THE INVENTION
[0010] The present invention involves a novel intelligent
treadmill, adaptations to existing treadmills, and associated
methodology. According to an aspect of the invention, the
intelligent treadmill comprises the means of allowing the runner to
automatically change the conveyer belt speed hands free, which can
be done consciously or unconsciously. The hardware and algorithms
involved are detailed in the invention. Upon changing the speed,
the runner still keeps a more or less fixed position in space
related to the indoor environment where the treadmill is placed.
These means are in addition to the standard method of changing belt
speed, that is, by the standard controllable manual speed settings
or automatic exercise profiles. The automatic, hands free speed
changing aspect of the present invention helps alleviate the
unrealistic constant speed aspect of standard treadmills, which
requires runners to consciously utilize an interface to adjust even
minor changes in speed.
[0011] According to another aspect of the invention, the
intelligent treadmill also comprises the means of allowing users to
perceive in real time how their surroundings would be changing if
they were in fact walking or running not-in-place. In addition, the
intelligent treadmill aspect of the present invention comprises the
means of simulating, communicating, and displaying the real time
positions of two or more treadmill runners on different treadmills
within said perceived surroundings. In other words, two or more
treadmill users can perceive not only how they are progressing
through the chosen surroundings; the present invention is also
capable of including the position of other treadmill users within
the surroundings in real time. These two former aspects of the
present invention create a more realistic treadmill user experience
for a runner to check his own or his running partners' progress by
simply knowing the chosen surroundings.
[0012] According to another aspect of the invention, the
intelligent treadmill also comprises the means of automatically
varying the incline, fan speed, or other features on the treadmill
to correspond to the conditions of the automated surroundings as
well as for the comfort of the runner. By way of example only,
imagine one course transitions from a hilly, wooded area to a flat
beach. The intelligent treadmill may automatically adjust from an
incline to zero incline based on the current position of the runner
along the simulated trail, have the cooling fan at low speed in the
wooded area turned to high speed near the beach (e.g., the wooded
area has little moving air while there is a breeze next to the
beach), and adjust the brightness of illumination of the treadmill
from dim to bright (e.g., the tree cover in the wooded area blocks
the sun while the sun is shining next to the beach). This is a kind
of environmental background controls. According to another aspect
of the invention, sound of bird singing can be played in the
simulated wooded area, and sound of sea waves near the simulated
beach.
[0013] According to an aspect of the invention, the present
invention comprises a two or three phase AC induction motor, or a
Brushless DC (BLDC) motor to drive the treadmill conveyor belt for
better transient response as well as higher energy efficiency. The
unique advantage of AC induction or BLDC motors in the context of
the present invention is due to faster transient belt speed changes
as compared with conventional treadmills, i.e., the present
invention allows for automatic, hands free changing of the conveyor
belt speed based on the sensing hardware and algorithms of this
invention. At the same time, energy saving can be achieved. A
previous invention involves the use of ultrasound distance
measurement but the precision achieved was found not good enough
for our application. An aspect of the invention makes use of laser
technology for dynamic position sensing of the runner on the
running belt. Another aspect of the invention makes use of pairs of
poles, equipped with laser based obstacle sensors and installed by
the two sides of the running belt, to detect the current position
of the runner. One pair of poles installed at the rear of the
treadmill helps to initiate an emergency stop when the runner falls
back to such position. Due to this nature of the present invention,
another aspect of the present invention comprises standard vectored
control algorithms which utilize the relatively high transient
torque of such AC or BLDC motors. In other words, the AC or BLDC
motors are much more suitable for sudden acceleration and
deceleration than the standard DC motors that have only one
dimension of control, i.e. the DC current fed to the rotor. In this
way, the response of AC or BLDC motors is even more immediate to
fit the runner's performance. Furthermore, BLDC motors have a much
higher torque-to-motor volume ratio, good for replacing traditional
DC motors. In addition, AC and BLDC motors require less maintenance
than standard DC motors used in conventional treadmills. Finally,
the use of 3-phase AC or BLDC motors can improve energy
efficiency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] These and other features, aspects, and advantages of the
present invention will become better understood with regards to the
following description, appended claims and drawings where:
[0015] FIG. 1 is a schematic representation of the structure of the
intelligent treadmill of the present invention;
[0016] FIG. 2 is a schematic representation of the mechanism of
distance measurement of the intelligent treadmill of the present
invention;
[0017] FIG. 3 is a schematic representation of the monitor display
of the intelligent treadmill of the present invention;
[0018] FIG. 4 is a schematic representation of first embodiment of
measured distance by using laser reflector method of the
intelligent treadmill of the present invention;
[0019] FIG. 5 is a schematic representation of second embodiment of
measured distance by using three pair of poles and equipped with
two sets of reflectors/receivers method of the intelligent
treadmill of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] Referring to FIG. 1 of the drawings and in accordance with
the principles of the invention, the intelligent treadmill
comprises a touch screen monitor (1), transmitter/receiver (2),
motor (3), electronic drive (4), control panel (5), reflector (6)
and three pairs of poles (7), (8) and (9).
[0021] The said touch screen monitor (1) is equipped with a pair of
loudspeakers and a dimmable lamp, displaying the video of the
surrounding environment of an outdoor track, downloaded from the
Internet and a simple map showing runner current position.
[0022] The said transmitter/receiver (2) is for distance
measurement, which emits and receives a laser beam to help estimate
the exact distance of the reflector of the runner away from it.
[0023] The said motor (3) is a vectored controlled 2/3-phase AC or
BLDC motor that adjusts the speed of the conveyor belt to fix the
runner at a more or less constant distance from the
transmitter/receiver or at a dynamically stable and stationary
position on the moving belt.
[0024] The said 2/3-phase AC or BLDC motor (3) is energized by an
electronic drive (4) which gets power from a standard single phase
supply.
[0025] The said control panel (5) is to control the speed of the
treadmill and has additional control to adjust the speed of the
conveyor belt to fix the user at a more or less constant distance
from the transmitter/receiver (2) or at a dynamically stable and
stationary position on the moving belt.
[0026] The said reflector (6) is worn on the waist belt of the
runner, which is used to reflect the laser beam from the
transmitter/receiver (2).
[0027] The said poles (7), (8) and (9) are installed on both sides
of the platform of the said treadmill equipped with laser based
transmitters, receivers and/or reflectors.
[0028] Every pole of a pair is situated on either side of the belt
and the whole pair can move along the belt on rails underneath the
platform on and below which the belt is moving. The initial
positions of these poles are factory preset while the user can
slightly adjust that of (8) and (9), but not (7). Without loss of
generality, as an example, on pole (7) of one side, there are two
transmitters/receivers, known as (7A) and (7B) ((A) being higher
than (B) at about 300 mm and 150 mm respectively above the belt
surface). On pole (7) of the other side, at the same levels, there
are two reflectors, also known as (7A) and (7B). A laser beam is
projected from transmitters (7A) and (7B) on one side to reflectors
(7A) and (7B) on the other side and then received by receivers (7A)
and (7B) on the same side of the transmitters respectively. This
arrangement equally applies to pole-pairs (8) and (9). Such six
sets of transmitters/reflectors/receivers can detect any blockage
of the laser beam in the midst. According to an alternative aspect,
only the transmitters are installed on the poles of one side while
the receivers are installed on the poles of the other side. In this
way, the reflector is omitted. Both designs serve the same purpose
of detecting blockage of the laser beam in the midst.
[0029] Referring to FIG. 2, the drawing shows the mechanism of
distance measurement. According to one aspect, a transmitter (2)
continuously emits a laser beam which is reflected by a reflector
(6) on the waist belt of the runner and picked up by a receiver
(2). In this way, the accuracy of distance measurement is more
precise because only the position of the abdomen of the runner is
of concern. Even the posture of the runner changes, the abdomen
remains more or less at the same position. Once the exact position
of the reflector (6) is estimated, the position of the centre of
gravity of the runner is calculated by adding half the thickness of
the human body. The control algorithm as described in the following
description controls the speed of the motor (3) to bring the runner
at a more or less fixed position dynamically related to any
stationary part of the treadmill. According to another aspect of
position measurement, FIG. 2 also gives the side view of the three
position measurement poles (7), (8) and (9), each with two
transmitters/receivers and/or reflectors (A) and (B), depending on
which side of the treadmill is shown in the figure.
[0030] Referring to FIG. 3, the drawing shows the normal display on
the monitor (1) when the runner is treading along a preset track
with or without partners, downloaded through the Internet, though
other displays for user's setting are available. On the left, a
simple map showing the trail is displayed with the starting/end
point indicated. A dot, say red in color, indicates the
instantaneous position of the runner while other dots of different
colors, indicate the instantaneous positions of his partners as
retrieved through the Internet. In this way, the runner knows his
current position as well as that of his partners. It's like GPS
navigation on the road map. Parameters including but not limited to
the instantaneous speed of the runner, average speed of the whole
group, percentage of track completed, and time remaining to finish
the whole track are displayed under the map. On the right, a video
of the surrounding environment of the trail, synchronous to the
current speed and position of the runner, is displayed. If the
runner runs faster, the video is played faster, and vice versa.
[0031] Referring to FIG. 4, the drawing shows how parameters are
defined for belt speed and dynamic runner's position control when a
reflector (6) on the waist belt worn by the runner is used to
reflect the laser beam from the transmitter (2).
[0032] Referring to FIG. 5, the drawing shows how parameters are
defined for belt speed and dynamic runner's position control when
no waist belt is needed and position of runner is measured by the
three pairs of poles (7), (8) and (9), each equipped with two sets
of transmitters/receivers and/or reflectors (A) and (B).
[0033] Illustrative embodiments of the functioning of the invention
are described below. In the interest of clarity, not all features
of an actual implementation are described in this specification. It
will of course be appreciated that in the development of any such
actual embodiment, numerous implementation-specific decisions must
be made to achieve the developer's specific goals, such as
compliance with system-related and business-related constraints,
which will vary from one implementation to another. Moreover, it
will be appreciated that such a development effort might be complex
and time-consuming, but would nevertheless be a routine undertaking
for those of ordinary skill in the art having the benefit of this
disclosure. The novel treadmill, adaptations to existing
treadmills, and associated methodology disclosed herein boast a
variety of inventive features and components that warrant patent
protection, both individually and in combination.
[0034] By way of examples only, a description of one embodiment of
the automatic, hands free conveyor belt speed changer, the real
time and interactive surroundings display, and associated
methodology will be discussed. The automatic speed changer aspect
of the invention addresses the unrealistic constant speed aspect of
standard treadmills. For standard treadmills, users fix a belt
speed which remains constant until the user modifies the speed
manually. Only during the transition from one fixed belt speed to
another fixed belt speed that there is short termed acceleration or
deceleration. Obviously, the user must maintain a fairly constant
velocity, i.e., if the user walks/runs too fast he will step off of
the belt in the front of the machine onto the footrest covering the
belt sheave/motor assembly underneath the control panel (5) or if
he walks/runs too slow he will step off of the belt onto the floor.
However, under standard treadmills, the fact that the run-able belt
length is longer than one's stride allows the runner may
momentarily slow or speed up his pace, which would move him toward
or away from the front of the treadmill from his previous location,
respectively. Then, the user can either revert back to his original
speed and stay in the new location on the treadmill or momentarily
speed up or slow down to reposition himself back to the original
location, respectively. Regardless, current treadmills only allow
users to speed up or slow down momentarily in that the belt speed
is constant (with manual adjustment of the belt speed on rare
occasions). An aspect of the present invention adjusts the belt
speed automatically to fit the runner's desired change in velocity.
For instance, if the runner begins to run faster, the belt will
move faster, and vice versa. The ultimate target is to bring the
dynamic position of the runner to the middle of the treadmill even
when his speed keeps on changing.
[0035] According to an aspect of the invention, the treadmill
includes one or more means of accurately measuring the distance
between the runner and the front of the treadmill or ensuring the
runner is dynamically trapped between two pairs of measurement
poles. By way of example only, the intelligent treadmill uses a
laser transmitter and receiver pair (2) (called the locator) which
are installed right below the control panel (5). The height of the
locator is adjustable to suit the level of the reflector (6). A
previous invention (U.S. Pat. No. 6,733,423 B1 dated May 11, 2004)
utilized an ultra-sound transmitter and receiver to measure the
position of the runner on the running belt; that previous invention
claimed that once the position was estimated, the speed of the belt
could be adjusted. Upon implementing the methodology, three
problems were found. First, ultra-sound waves hit the runner at
different spots and therefore the reflected waves indicated a
mixture of the position of different parts of the runner's body,
thus significantly downgrading the accuracy. Second, the precision
of ultra-sound distance measuring technology is well below the
requirement which should be within a range of .+-.20 mm. Third,
nothing on the speed control algorithm was mentioned in that
previous invention. The locator measures the distance from itself
to the runner's waist or other part of the runner's body equipped
with a reflector (6), thus one single point of reflection. For
instance, the user could wear a reflector on the middle front spot
of the waist belt to reflect the laser beam. If accidentally the
reflector (6) is out of sight from the laser team emitted by the
transmitter (2), the belt speed remains unchanged.
[0036] According to an aspect of the invention, the intelligent
treadmill utilizes this one or more measured distances of the
runner to change the speed of the belt in order to fix the position
of the runner dynamically at a desirable distance from a reference
point on the treadmill, say at the middle of the belt. The dynamic
position control algorithm related to this type of distance
measurement is as follows, with reference to FIG. 4.
[0037] X.sub.o is the desirable permanent position of the runner,
say at the middle point along the moving belt, as measured from the
laser transmitter/receiver (2). The running speed of the runner is
s(t), a function of time t, with respect to the belt, not the
indoor environment; the speed of the running belt is v(t), also a
function of time, under continuous control by the system based on
the dynamic position of the runner with respect to the indoor
environment. The instantaneous horizontal distance between the
centre of gravity of the runner and a stationery reference point
right below the control panel (5) is given by x(t), also a function
of time, which includes the distance, l, measured by the laser
transmitter/receiver (2) and half the assumed thickness of the
runner, about 0.15 m. Such added value can be keyed in by the
runner.
[0038] The equation of dynamics is given by:
x t = ( v - s ) ##EQU00001##
while the equation of the control algorithm is given by:
v t = - K P ( x - X o ) - K I .intg. ( x - X o ) t 2 x t 2 = v t -
s t = - K P ( x - X o ) - K I .intg. ( x - X o ) t - s t
##EQU00002##
Here, K.sub.p and K.sub.I are two factory pre-tuned positive real
numbers which are the proportional gain and the integral gain
respectively. Since s is arbitrarily varying due to the runner,
this differential equation can only be solved once s is known with
a goal to make .parallel.x-X.sub.o.parallel..sup.2 as small as
possible. Having said that, the equation
v t = - K P ( x - X o ) - K I .intg. ( x - X o ) t ##EQU00003##
is good enough to facilitate the speed control action because x is
measurable while all other parameters on the right handed side of
the equation are known. An emergency stop is actuated when x(t)
goes beyond a limit, indicating that the runner has been too close
to the end of the moving belt.
[0039] Even a laser distance measuring system is used, the accuracy
is still imprecise and sometimes non-deterministic because the
posture of the runner keeps on changing on the belt. Also, it is
easy that the reflector (6) cannot receive the laser team and is
out of sight of the receiver (2). Hence, the measured x cannot
accurately indicate the exact position of the centre of gravity of
the runner.
[0040] In another aspect of the invention, the dynamic position of
the runner is precisely kept within a confined spatial segment
above the moving belt determined by two pairs of obstacle sensing
poles (8) and (9) as shown in FIG. 5. Another pair of obstacle
sensing pole (7) is for safety precaution as it indicates the end
of the belt. The exact position of the poles is pre-designed but
the runner can slightly adjust that of (8) and (9), but not (7). As
shown in FIG. 1, obstacle sensing poles come in pairs, one on
either side of the moving belt and they could be moved together
along the belt on rails below the platform. On each pair of poles,
one on either side of the belt, there are two laser
transmitters/receivers on one side and two laser reflectors on the
other side, (A) and (B) respectively. An alternative design does
not involve the reflector, while transmitters (A) and (B) are on
one side and receivers (A) and (B) are on the other side. Without
loss of generality, a laser beam is projected from a transmitter
(9A) on one side to a reflector (9A) on the other side, reflected
back and received by a receiver on the transmitter side (9A). (9B),
(8A), (8B), (7A) and (7B) work similarly. A flag which is binary,
either "1" or "0", is assigned by the control microprocessor to
indicate whether any transmitter/reflector/receiver combination of
a pole is blocked by an obstacle in the midst, e.g. the flag of
(9B)="1" when blocked or ="0" when clear. For this particular
application, the obstacle that blocks is either the shoe, the foot
or the leg of the runner because (A) is only less than 300 mm and
(B) 150 mm above the moving belt. The dynamic position control
algorithm for this setup is as follows, reference made to FIG. 5
again. Under this control algorithm, during operation, the runner
is dynamically trapped in a spatial segment above the moving belt
between pole pair (8) and pole pair (9), irrespective of his
posture.
[0041] Pole pair (9) is at a horizontal distance X.sub.f (f means
front) from a reference point, say at the front rotating sheave of
the belt right below the control panel (5). Pole pair (8) is at
distance X.sub.r (r means rear) from the same reference point and
Pole pair (7) is at a distance X.sub.e (e means end) from the same
reference point. The desirable dynamic position of the runner is
still at X.sub.o from the reference point as shown in FIG. 4, which
is in the middle between X.sub.f and X.sub.r. X.sub.f is factory
pre-adjusted to about X.sub.o-0.3 m and X.sub.r to X.sub.o+0.3 m,
bearing in mid that the runner can slightly adjust that. However,
X.sub.e marks the end of the belt, which cannot be adjusted. Again,
v(t) is the instantaneous speed of the moving belt under control
and it obeys the following control algorithms in Table 1. The
binary flags are checked within a time period of one complete
control cycle taken by the belt to travel twice a distance of
(X.sub.r-X.sub.f), thus dependent on the speed of running belt, v.
One complete control cycle is the average total time spent by two
strides completed by the left and right feet of the runner, equal
to one cycle of walking or running on the belt. For example, if the
factory preset positions of (8) and (9) are unchanged, they are
about 0.6 m apart, and the time period of one control cycle is then
equal to 1.44 second if the instantaneous belt speed is 3 km/hr.
Once a flag is equal to "1" at anytime within the control cycle, it
is assigned a value of "1" for the whole control cycle. And the
control action is determined and executed at the end of every
control cycle, after which all flags are automatically reset to
"0".
[0042] In Table 1, K.sub.I bears the same meaning as the factory
pre-tuned positive parameter which is the integral gain; C.sub.1 is
the acceleration of the belt (positive or negative) at the
beginning of the current control cycle; C.sub.2 is the moving belt
speed of the current control cycle.
TABLE-US-00001 TABLE 1 Action at the Equivalent beginning of Action
for the Flags of 7: A Flags of 8: A Flags of 9: A next control next
control and B and B and B cycle cycle All "0" All "0" Either one
"1" dv dt = K I .intg. dt ##EQU00004## dv dt = K I t + C 1
##EQU00005## All "0" Either one "1" Either one "1" dv dt = 0
##EQU00006## v = C.sub.2 All "0" All "0" All "0" dv dt = 0
##EQU00007## v = C.sub.2 All "0" Either one "1" All "0" dv dt = - K
I .intg. dt ##EQU00008## dv dt = - K I t + C 1 ##EQU00009## Either
one "1" Whatever Whatever v = 0 Maximum deceleration to a safe
stop
[0043] One feature of the present invention allows for and utilizes
the fact that the runner basically maintains a more or less fixed
spatial position relative to the treadmill when the
transmitter/receiver (2) is utilized. According to an aspect of the
invention, the intelligent treadmill can learn this desired
operating position, by way of example only, via the controller
during the parameter setting stage when the runner is running on
the moving belt under a constant speed. The controller then knows
where the runner feels comfortable on the moving belt. Or the user
can slightly and manually adjust the positions of the two pole
pairs (8) and (9) to change the exact spatial segment to which the
runner's position is dynamically confined. To expand on one example
above, when the treadmill is turned on, it runs at a constant speed
and it takes, say, half a minute for the treadmill controller to
learn the comfortable position of the runner when obstacle sensing
pole pairs are not utilized. Then, the treadmill will go to the
automatic speed or dynamic position control mode where the position
of the runner is dynamically fixed at a distance from the
transmitter (2) and an "automatic speed control" indicator is lit
up on the control panel (5). If the obstacle sensing pole pairs are
active, no such tuning is necessary.
[0044] According to an aspect of the invention, the treadmill
includes the means of automatically stopping the conveyor belt in a
short period of time, whether it is for emergency or other reasons.
By way of example only, it is contemplated that the automatic
stopping means utilize the activation of any one of two obstacle
sensing devices on pole pair (7), in combination to or separate
from other means, thus fully replacing standard function (9) of a
conventional treadmill as mentioned before.
[0045] In this invention, motors (3) for home treadmills will
either be 2/3-phase AC induction motors or BLDC (brushless DC)
motors, with a rated capacity up to 3 kW though in real operation,
they are usually not fully loaded with the help of vector
controlled PWM (pulsed width modulation) voltage pulses while a
high efficiency can be maintained. Vector controlled PWM voltage
and current control can ensure and improved transient response of
speed control and energy efficiency. Electrically, there is no
difference between a 2-phase AC motor and a 3-phase AC motor when
either one is driven by a PWM based Variable Voltage and Variable
Frequency drive.
[0046] According to an aspect of the invention, the intelligent
treadmill has the means of allowing the user to connect to,
download, and upload data between the treadmill and other computer
devices, data storage devices, the Internet (either wireless or
wired), or other ways of transferring and receiving data. By way of
example only, one scenario of the functioning of the treadmill will
be discussed. It is appreciated that this is only one example of an
embodiment of the present invention, which only includes a number
of applications of the features of the present invention. The
treadmill includes the provision of a "mobile app" on a standard
smart phone. Video clips of popular trails or tracks of the natural
environment with beautiful scenery are provided and downloaded onto
the smart phone which is connected to the Internet through Wi-Fi or
data through cell phone carriers and to the control panel (5)
through Bluetooth or Wi-Fi. When the runner is running on the belt,
the surrounding environment keeps on changing, synchronous to his
own pace, controlled to fit by the belt speed, and is displayed on
the monitor (1) as if he were running on the real natural
environmental track outdoor. This is like the on-site navigation
service provided on the Google map. By the side of the video, the
track is shown on a small map while the current position of the
runner is highlighted by a particular symbol, say a red dot. Under
the map, information including but not limited to information such
as current average speed of runner, average speed of the group,
percentage of track completed by the runner and estimated time to
finish the whole track under the current speed etc. are displayed.
In this way, the runner can know where he is at present and see the
natural environment at this particular position of the real track.
If he runs faster or slower, the video and the symbol on the map
will match in synchronism. The algorithm is described as
follows.
[0047] The video of treading the track of the natural environment
is filmed by a mobile camera of the service provider under a
constant speed of movement, V.sub.f, say 0.5 m/s, using a constant
frame rate, fr, say 25 frames per second, as examples, but there
could be other choices of V.sub.f and fr. The position, p, a real
number in meters, of the runner on the simulated track at any
instant, t, as experienced by the runner is estimated from the
starting point of the track when t=0 second, i.e. the time when the
runner starts to tread on the treadmill. If the instantaneous
treading speed of the runner on the treadmill, s(t) almost equal to
v(t) based on the control algorithms of this invention, is known
and recorded, p(t) is estimated to be:
p ( t ) = .intg. 0 t v t . ##EQU00010##
[0048] Since the video was filmed by a mobile camera under constant
speed, V.sub.f, each frame on the video corresponds to a particular
position on the track because advancing one frame on the video
implies advancing the track by V.sub.f/fr meters. In this case,
p(t) actually relates to (p*fr)/V.sub.f, rounded to the nearest
integer, which is the current frame number on the video. Such frame
number is also equivalent to the video time code of a linear time
code format. The controller of the treadmill keeps on tracking v(t)
and thus p(t) and hence the number of frames elapsed since the
beginning when t=0 s. If L is the total length of the whole track,
current percentage finished by the runner as shown below the map on
the monitor (1) is calculated by (p/L)*100%. It is this value p(t)
that is used by the control system of the treadmill as a tag to
advance the video and change the environmental background, such as
slope of treadmill platform, music, speed of circulating fan, and
illumination etc., synchronously as experienced by the runner with
reference to the following table, Table 2, which is downloaded from
the "mobile app" for a particular track. Table 2 includes those
parameters for environmental background controls.
TABLE-US-00002 TABLE 2 p % slope or tilting frame number music
level of speed of in of angle of tread- or time code or illumi-
circulating m L mill platform on video sound nation fan (%)
file
[0049] Basically, the playing speed of the video is synchronous
with v(t), given by: [v(t)/V.sub.f]*[normal playing speed equal to
the filming speed], while the exact instantaneous scene of the
video is synchronous with p(t).
[0050] Since the whole system is Internet connected, according to
an aspect of this invention, the runner can invite partner(s) to
run or jog on the same track as involved in one exercise. All
involved could see similar video but the exact scene depends on the
instantaneous position of each individual runner along the agreed
track. In other words, each runner involved in the exercise has his
own p(t). And all of them could see their exact positions on the
map by the side with different symbols, say dots of different
colors as examples. This is because different p(t) of different
runners are exchanged through the Internet so that the controller
of every treadmill knows the exact p(t) of every other runner
involved in the exercise, in addition to the local runner. The
instantaneous position p(t) of each individual runner is calculated
by the speed of belt synchronous to the varying running speed of
each individual runner while the environmental background control
is synchronous with each individual runner. The only parameters
that are exchanged between the treadmill controllers of different
runners are the various p(t) of different runners. In this way,
those running slower could speed up or slow down to catch up with
other partners and vice versa.
[0051] At the same time, they can talk to one another through the
smart phones or the Internet and a background sound and music of
that environment is played to improve the fidelity based on the
data file as shown in Table 2 downloaded from the "mobile app".
Runners virtually at the same spot on the simulated track enjoy the
same background, including but not limited to tilting angle of the
belt, sound or music file, level of illumination and the speed of
the circulating fan. But runners who have finished different
percentage of the track experience different video and background.
Sound from the loudspeakers of the monitor (1) and speed of the
circulating fan on the control panel (5) are adjusted accordingly
to reflect the environment shown by the video. Tracks are updated
from time to time by the service provider so that the scenery of
different seasons of the same track is available for downloading to
enhance the treading experience of the runner and his partners. The
tilting angle of the platform and the running belt of the treadmill
is continuously adjusted according to the instantaneous position of
the track which simulates the real natural environment. In this
way, the runner has an up-climbing experience when the track is
leading to a hill. Subject to the existing limitation of treadmill
design, the tilting angle can at most be lowered to zero degree,
i.e. horizontal. In the future, new treadmill design may include a
down tilting angle to fit the simulated track.
[0052] Although the present invention has been described in
considerable detail in reference to preferred versions, other
versions are possible. Therefore, the spirit and scope of the
appended claims should not be limited to the description of the
preferred versions contained herein.
* * * * *