U.S. patent application number 13/201728 was filed with the patent office on 2011-12-08 for system and method for bed height adjustment.
This patent application is currently assigned to KONINKLIJKE PHILIPS ELECTRONICS N.V.. Invention is credited to Andreas Brauers, Kai Eck, Kurt Stadlthanner.
Application Number | 20110296607 13/201728 |
Document ID | / |
Family ID | 42157765 |
Filed Date | 2011-12-08 |
United States Patent
Application |
20110296607 |
Kind Code |
A1 |
Stadlthanner; Kurt ; et
al. |
December 8, 2011 |
SYSTEM AND METHOD FOR BED HEIGHT ADJUSTMENT
Abstract
There is provided a control system for an adjustable height bed,
the adjustable height bed having a raised position and a lowered
position, the control system comprising an input for receiving
signals from a sensor located in the adjustable height bed; and a
processor for processing the received signals to determine the
status of a user relative to the bed and for generating control
signals for adjusting the bed to the raised position or to the
lowered position on the basis of the determined status.
Inventors: |
Stadlthanner; Kurt; (Aachen,
DE) ; Brauers; Andreas; (Aachen, DE) ; Eck;
Kai; (Aachen, DE) |
Assignee: |
KONINKLIJKE PHILIPS ELECTRONICS
N.V.
EINDHOVEN
NL
|
Family ID: |
42157765 |
Appl. No.: |
13/201728 |
Filed: |
February 16, 2010 |
PCT Filed: |
February 16, 2010 |
PCT NO: |
PCT/IB10/50696 |
371 Date: |
August 16, 2011 |
Current U.S.
Class: |
5/11 |
Current CPC
Class: |
A61G 7/012 20130101;
A61G 7/018 20130101 |
Class at
Publication: |
5/11 |
International
Class: |
A47C 31/00 20060101
A47C031/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 20, 2009 |
EP |
09153276.02 |
Claims
1. A control system for an adjustable height bed, the adjustable
height bed having a raised position and a lowered position, the
control system comprising: an input for receiving signals from a
sensor located in the adjustable height bed; and a processor for
processing the received signals to determine the status of a user
relative to the bed and for generating control signals for
adjusting the bed to the raised position or to the lowered position
on the basis of the determined status.
2. A control system as claimed in claim 1, wherein, in the event
that the processor determines the status to be that the user has
got or is getting out of the bed, or is sat on the edge of the bed,
the processor is configured to generate control signals for
adjusting the bed to the raised position, or for maintaining the
bed in the raised position, if the bed is already in the raised
position.
3. A control system as claimed in claim 2, wherein the processor is
configured to determine that the user has got or is getting out of
the bed, or is sat on the edge of the bed, in the event that the
amplitude of the received signals is below an amplitude
threshold.
4. A control system as claimed in claim 1, wherein, in the event
that the processor determines the status to be that the user is on
the bed lying down, the processor is configured to generate control
signals for adjusting the bed to the lowered position, or for
maintaining the bed in the lowered position, if the bed is already
in the lowered position.
5. A control system as claimed in claim 4, wherein the processor is
configured to determine that the user is in bed lying down in the
event that the amplitude of the received signals is above an or the
amplitude threshold and a variance of the received signals is below
a variance threshold.
6. A control system as claimed in claim 1, further comprising a
user-operable control that is configured to cause the processor to
generate control signals for adjusting the bed to the raised
position or to the lowered position in response to a user
input.
7. An adjustable height bed, comprising: a bed or mattress portion;
a sensor associated with the bed or mattress portion; an adjustable
height mechanism for adjusting the height of the bed or mattress
portion to the raised position or to the lowered position; and a
control system as claimed in any preceding claim coupled to the
sensor and the adjustable height mechanism, the control system
being configured to generate control signals for the adjustable
height mechanism.
8. A method of operating an adjustable height bed, the adjustable
height bed having a raised position and a lowered position, the
method comprising: receiving signals from a sensor located in the
adjustable height bed; processing the received signals to determine
the status of a user relative to the bed; and adjusting the bed to
the raised position or to the lowered position on the basis of the
determined status.
9. A method as claimed in claim 8, wherein, in the event that it is
determined that the status is that the user has got or is getting
out of the bed, or is sat on the edge of the bed, the step of
adjusting comprises: adjusting the bed to the raised position or
maintaining the bed in the raised position if the bed is already in
the raised position.
10. A method as claimed in claim 9, wherein the step of processing
determines that the user has got or is getting out of the bed, or
is sat on the edge of the bed, in the event that the amplitude of
the received signals is below an amplitude threshold.
11. A method as claimed in claim 8, wherein, in the event that it
is determined that the status is that the user is on the bed lying
down, the step of adjusting comprises: adjusting the bed to the
lowered position or maintaining the bed in the lowered position if
the bed is already in the lowered position.
12. A method as claimed in claim 11, wherein the step of processing
determines that the user is in bed lying down in the event that the
amplitude of the received signals is above an or the amplitude
threshold and a variance of the received signals is below a
variance threshold.
Description
TECHNICAL FIELD OF THE INVENTION
[0001] The invention relates to a system and method for adjusting
the height of a bed, and in particular to a system and method that
reduces the risk of injury to a person using the bed.
BACKGROUND TO THE INVENTION
[0002] Preventing people falling at night is one of the major
issues in the care of the elderly. It has been found that a
substantial number of falls by the elderly occur in the bedroom,
and in particular occur when getting into or out of bed.
[0003] Two ways of tackling this problem are for beds of patients
that are prone to falling to be equipped with bed rails or for the
patient to be restrained in the bed. However, both of these
measures have significant disadvantages, namely that patients with
dementia can often try to climb out of bed over the bed rails,
which can lead to an even more severe fall, and restraints can lead
to the patient becoming aggressive and the restraints are not
tolerated by relatives of the patient.
[0004] A much more accepted way to reduce falls at night is to
provide a bed that can be lowered when the patient is in the bed so
that they sleep quite close to the floor. In this way, the distance
that the patient can fall is reduced and the risk of severe
injuries is thereby reduced.
[0005] Of course, a problem with these beds is that it is difficult
for the patient to get out of bed when it is in a lowered position.
For this reason, adjustable height beds can usually be lifted
electronically using an associated control unit. These control
units can be hard to handle for elderly patients who suffer from
reduced sensitivity or flexibility of their hands and/or from
limited vision. Furthermore, patients with dementia can often find
it difficult to handle and operate electrical devices.
[0006] Thus, this means that patients can sometimes try to get up
when the bed is in the lowered position, which is much more
difficult and can even lead to additional falls. Moreover, patients
who have adjusted their bed to an adequate height before getting up
may not lower the bed back to a safer position when they get back
into the bed.
[0007] Therefore, there is a need for a system and method that can
overcome the difficulties with conventional height-adjustable
beds.
SUMMARY OF THE INVENTION
[0008] According to a first aspect of the invention, there is
provided a control system for an adjustable height bed, the
adjustable height bed having a raised position and a lowered
position, the control system comprising an input for receiving
signals from a sensor located in the adjustable height bed and a
processor for processing the received signals to determine the
status of a user relative to the bed and for generating control
signals for adjusting the bed to the raised position or to the
lowered position on the basis of the determined status.
[0009] According to a second aspect, there is provided an
adjustable height bed comprising a bed or mattress portion; a
sensor associated with the bed or mattress portion; an adjustable
height mechanism for adjusting the height of the bed or mattress
portion to the raised position or to the lowered position; and a
control system as described above coupled to the sensor and the
adjustable height mechanism, the control system being configured to
generate control signals for the adjustable height mechanism.
[0010] According to a third aspect, there is provided a method of
operating an adjustable height bed, the adjustable height bed
having a raised position and a lowered position, the method
comprising receiving signals from a sensor located in the
adjustable height bed; processing the received signals to determine
the status of a user relative to the bed; and adjusting the bed to
the raised position or to the lowered position on the basis of the
determined status.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Exemplary embodiments of the invention will now be
described, by way of example only, with reference to the following
drawings, in which:
[0012] FIG. 1 is a block diagram of a height adjustable bed and
control system in accordance with the invention;
[0013] FIG. 2 is a block diagram of the control system;
[0014] FIG. 3 is a graph illustrating an exemplary set of signals
from a pressure sensor;
[0015] FIG. 4 is a graph illustrating the variance of the exemplary
set of signals in FIG. 3 and
[0016] FIG. 5 is a flow chart of the algorithm according to the
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0017] FIG. 1 shows an exemplary adjustable height bed 2 and
control system 4 according to the invention. The adjustable height
bed 2 has a bed or mattress portion 6 that a user can sit or lie
on, a base 8 and some adjustable height mechanism 10 for adjusting
the height of the bed or mattress portion 6.
[0018] The adjustable height mechanism 10 adjusts the height of the
bed or mattress portion 6 between at least a raised position, at
which it is easier for the user to get off of the bed 2, and a
lowered position, at which the risk of the user injuring themselves
if they roll out of the bed 2 is reduced. The difference in height
between the raised and lowered positions can be of the order of 0.5
m -1 m.
[0019] In a preferred embodiment, the bed 2 can be configured for
use by a specific user. In particular, the specific height of the
bed or mattress portion 6 above the floor in each of the raised and
lowered positions can be adjusted for different users. For example,
the raised position could be set higher for a tall person than for
a short person. This configuration for a specific user can be
achieved through suitable control of the adjustable height
mechanism.
[0020] The control system 4 is coupled to, and controls the
operation of, the adjustable height mechanism 10.
[0021] A sensor 12 is provided in or on the bed or mattress portion
6 for sensing force or pressure exerted on the bed or mattress
portion 6 by the user. Signals from the sensor 12 are provided to
the control system 4. Preferably, the sensor 12 is placed in or on
the bed or mattress portion 6 such that it will be located under
the thorax of the user when they are lying appropriately on the bed
or mattress portion 6.
[0022] The sensor 12 can be a force sensor for measuring the forces
exerted on the bed or mattress portion 6 by the user, a pressure
sensor for measuring the pressure exerted on the bed or mattress
portion 6 by the user, or a strain gauge for measuring the strain
on the bed or mattress portion 6 caused by the user. In this latter
embodiment, the measurements from the strain gauge are used to
determine the pressure being exerted on the bed or mattress portion
6 by the user. In preferred embodiments, the sensor 12 is selected
from a piezoelectric switch, a piezoelectric foil, an electret foil
or a strain gauge. Those skilled in the art will appreciate that
alternative types of sensors can be used to perform the method in
accordance with the invention.
[0023] In accordance with the invention, the control system 4
processes the signals from the sensor 12 to determine the status of
the user relative to the bed (i.e. the user is lying down asleep,
sat of the edge of the bed 2, getting into or out of the bed 2 or
is out of the bed 2) and adjusts the height of the bed 2 to reduce
the risk of the user falling and/or the risk of the user injuring
themselves during a fall.
[0024] In particular, if it is determined that the user has got
into the bed 2 and is lying in the bed 2 (whether asleep or awake),
the height of the bed 2 is lowered so that the risk of the user
injuring themselves if they roll out of the bed 2 is reduced.
Furthermore, if it is determined that the user is sat on the edge
of the bed (which can be seen as a reliable predictor of the user
getting out of the bed 2), the user is getting out of the bed 2,
the height of the bed 2 is raised so that it is easier for the user
to stand up, thereby reducing the risk of the user falling.
[0025] The control system 4 preferably predicts or detects that the
user is going to get out of the bed 2 early enough so that the bed
2 can be raised to a safe height before the user actually gets out
of the bed 2. In addition, the control system 4 preferably
determines that the user is lying down safely before lowering the
bed 2, in order to reduce the risk that the user will fall out of
the bed 2 while it is lowered.
[0026] It will be appreciated that the height adjustments of the
bed 2 are performed automatically under the control of the control
system 4, and no user or care provider interaction is required.
[0027] FIG. 2 shows the control system 4 in more detail. The
control system 4 has an input 14 for receiving signals from the
sensor 12, a processor 16 that is coupled to the input 14 and which
processes the received signals to determine the status of a user
relative to the bed 2.
[0028] The processor 16 is coupled to an output 18 through which
signals for controlling the adjustable height mechanism 10 are
transmitted.
[0029] The control system 4 further comprises a memory 20 for
storing instructions for the algorithm used to process the signals
from the sensor 12 and for generating the control signals for the
adjustable height mechanism 10.
[0030] In some embodiments, the control system 4 can also include a
user-operable height control 22. This control 22 allows the user or
a care provider to manually control the adjustment of the height of
the bed or mattress portion 6 (or to override the bed height set by
the algorithm according to the invention).
[0031] Although the control system 4 is shown as being co-located
with the adjustable height bed 2, it will be appreciated that the
control system 4 can be located remotely from the bed 2, which
means that the signals from the sensor 12 will be transmitted to
the control system 4 for processing, and the signals for
controlling the height of the bed 2 will be transmitted back to the
adjustable height mechanism 10.
[0032] The algorithm executed by the processor 16 will now be
described in more detail.
[0033] FIG. 3 shows an exemplary set of signals received from a
pressure sensor 12. The exemplary set of signals represents various
different states of the user and the bed 2. FIG. 4 is a graph
showing the variance of the signals shown in FIG. 3.
[0034] In segment I, the bed 2 is unoccupied, i.e. the user is out
of the bed 2, and this is represented by the signal amplitude being
small (<-1500), as the sensor 12 is comparatively relaxed and
measures only the pressure exerted from the weight of the
mattress.
[0035] During segment II, the user sits on the edge of the bed 2
and gets ready to lie down. The centre of gravity of the user is
away from the sensor 12 (which is located in the middle of the bed
or mattress portion 6 around the point at which the thorax of the
user will be located when they are lying down), which means that
almost no additional pressure is detected.
[0036] Segment III shows the signal recorded when the user is lying
down. Lying down leads to signals with a high amplitude and a
comparatively large variance (as shown in FIG. 4).
[0037] In segment IV, the user is lying calmly on the bed 2. In
this segment, the thorax of the user is exerting considerable
additional pressure onto the sensor 12, which leads to high
amplitude signals being recorded. The variance of these signals is
small, however, as the user is not moving.
[0038] In segment V, the user sits up. A large, high variance
signal appears first which decays rapidly once the user has lifted
their upper body from the region of the bed 2 in which the sensor
12 is located. An amplitude smaller than a threshold value a.sub.in
indicates that the process of sitting up is almost finished.
[0039] During segment VI the user is sitting on the edge of the bed
2. In segment VII the user has got off of the bed 2, and the signal
indicates that the bed 2 is empty.
[0040] FIG. 4 shows the steps in the algorithm executed by the
processor 16.
[0041] The algorithm starts in step 101 at a time
t=t.sub.start.
[0042] In step 103, the height status of the bed 2 is determined
(i.e. whether the bed 2 is in the raised or lowered positions).
This determination can be made by examining the status of the
adjustable height mechanism 10, or by reading a status of the bed 2
from the memory 20.
[0043] At step 105, the next sample or signal a from the sensor 12
is read.
[0044] At step 107, the sample a is compared to the amplitude
threshold, a.sub.in. If a is less than the threshold value a.sub.in
the process moves to step 109.
[0045] As the amplitude of the signal a is below the threshold,
this indicates that the bed is empty or that the user is sat on the
edge of the bed, and the bed should be in the raised position.
Therefore, at step 109, if the status of the bed 2 is "high", the
bed 2 is left in the raised position and the method returns to step
105 in which the next sample a is read. However, if, at step 109,
the status of the bed 2 is "low" (i.e. it is in the lowered
position), the process moves to step 111 in which the bed 2 is
raised, and the status of the bed is set to "high".
[0046] The method then returns to step 105 in which the next sample
or signal a is read from the sensor 12.
[0047] Returning to step 107, if the amplitude of the signal a is
greater than the threshold value a.sub.in, the method passes to
step 113 in which the variance, var, of the signal is compared to
the variance threshold, var.sub.in.
[0048] If the variance is greater than the variance threshold, the
method returns to step 105 and the next sample a is read. In this
case, the user is on the bed, but either in the process of lying
down, sitting up or rolling over (as shown in segments III and VI
of FIG. 3). Therefore, adjustments of the bed height should be
avoided, as this could increase the risk of the user suffering a
fall.
[0049] If the variance is less than the variance threshold, the
method passes to step 115 in which the height status of the bed 2
is examined.
[0050] As the amplitude of the signal a is above the threshold and
the variance is below the variance threshold, this indicates that
the user is lying on the bed calmly, and the bed should be in the
lowered position. Therefore, if the bed status is "high", the bed
is lowered and the status of the bed is set to "low". The method
then returns to step 105 and the next sample a is read. If, at step
115, the bed status is "low", then the method returns to step 105
and the next sample a is read.
[0051] As described above, the control system 4 can be integrated
into the bed 2 or can be separate from the bed 2. In some
embodiments, the control system 4 can be integrated into existing
electronics in a bed 2 (for example the electronics for controlling
the adjustment of the height of the bed 2).
[0052] Furthermore, it will be appreciated that some height
adjustable beds 2 can also be electronically adjusted into a
chair-like configuration. In this case, it is possible for the
algorithm according to the invention to be adapted so that when the
bed 2 is moved into the raised position the bed 2 is also adapted
to change into the chair-like configuration, and vice versa.
[0053] In addition, although the exemplary embodiments described
above only make use of a single sensor 12, it will be appreciated
that it is possible to use more than one sensor 12.
[0054] Therefore, there is provided a control system for a height
adjustable bed that automatically adjusts the height of the bed
according to the status of the user relative to the bed. The bed
can be adjusted into a raised position if it is determined that the
user is getting into or out of the bed, or adjusted into a lowered
position if it is determined that the user is lying on the bed. In
this way, the risk of falls, and the risk of injury sustained
during a fall, can be reduced.
[0055] While the invention has been illustrated and described in
detail in the drawings and foregoing description, such illustration
and description are to be considered illustrative or exemplary and
not restrictive; the invention is not limited to the disclosed
embodiments.
[0056] Variations to the disclosed embodiments can be understood
and effected by those skilled in the art in practicing the claimed
invention, from a study of the drawings, the disclosure, and the
appended claims. In the claims, the word "comprising" does not
exclude other elements or steps, and the indefinite article "a" or
"an" does not exclude a plurality. A single processor or other unit
may fulfill the functions of several items recited in the claims.
The mere fact that certain measures are recited in mutually
different dependent claims does not indicate that a combination of
these measured cannot be used to advantage. A computer program may
be stored/distributed on a suitable medium, such as an optical
storage medium or a solid-state medium supplied together with or as
part of other hardware, but may also be distributed in other forms,
such as via the Internet or other wired or wireless
telecommunication systems. Any reference signs in the claims should
not be construed as limiting the scope.
* * * * *