1. What does bedridden mean?
Being bedridden and bed rest are two concepts which appear
to be similar, however, they are quite different. Bed rest refers
to a limited period of rest as prescribed by a doctor or as deemed
necessary because of an acute illness whereas being bedridden
has a more negative connotation and is described as a final state
that gradually leads to (social) death, according to Zegelin2
.
According to “Training Material – PT Protocol for Bedridden
Patients” a bedridden patient, for various reasons, has to stay in
bed for a long period3
.
Senility, obesity, accidents (traffic, work, home, sports, etc.),
strokes, and spinal injuries are the main causes for being
bedridden, i.e., a person with reduced mobility. Of these,
senility is by far the major cause. The number/ratio of seniors
increases as the quality of life and average life expectancy
increase. According to the United Nations Department of
Economic and Social Affairs/Population Division4
, the
percentage of the global population in 2011 aged 60+ was 11%,
and this figure is predicted to doubled (22%) by the year 2050.
However, the increase will be sharper in less developed
countries, for instance, in 2011, the percentage of the
population in Latin America aged 60+ was 10% and this figure
is expected to rise to 25% by the year 2050. Thus, it is clear that
the need for senior care giving is going to increase significantly.
Improvements in technology and awareness on health and
safety at work lead to a decrease in fatal and/or serious
accidents resulting in reduced mobility. Similarly, increases in
automation on production lines, especially for more dangerous
tasks, is reducing the number of accidents occurring at work.
Studies on autonomous cars will soon bear fruit by preventing
car accidents, i.e., traffic deaths and injuries. Despite these
favorable outcomes of technology, there are some undesired
side effects on communities, such as increased obesity levels
due to today’s less active lifestyles. The obesity ratio is
continually increasing throughout the world, mostly in
developed countries. Finkelstein et al.5
estimates increases in
the prevalence of obesity and severe obesity of 33% and 130%,
respectively, over the next two decades. A person with a body
mass index (BMI) ≥ 30 is considered to be obese and BMI ≥ 40
indicates severe obesity.
Booming assistive technology for bedridden persons
The severe adverse effects on health of being bedridden are
a leading motivation for scientists working in the area of
assistive technology. In brief, some of these side effects are:
 Muscle weakness/atrophy: Due to little or no exercise,
the muscles lose their strength resulting in patients
having difficulty standing or even sitting and using their
hands, etc.3
.
 Muscle shortness: Bedridden persons stay for long
periods without changing their orientation/posture.
When the muscles remain in the short position, they
Review of assistive technologies for bedridden
persons
Bilal Orun*, Carlos RDM Roesler*, and Daniel Martins*
Abstract
In 21st
century, everyday new inventions are being developed, launched and marketed to human being. Researches and
developments in technology and healthcare cause significant increase in the quality of life and average life expectancy. As the
statistical researches and forecasts told, it is not possible to ignore ageing population, resulting the need for laborious
caregiving. Caregiving is highly costly also; there is a big injury rate and day lost in caregiving facilities due to need for highly
physical workforce. Besides the well known paid caregiver cost, there is a huge unseen cost of informal caregiving by friends
and relatives e.g. $522 billion a year in the United States1
(Measured by estimating income lost during the time that unpaid
caregivers spend on eldercare). Assistive technologies come to play by reducing carer injuries and day lost, diminishing high
caregiving costs and helping caregivers as well as improving the quality of life for people with physical limitations. This paper
provides a wide review of assistive technologies for bedridden persons, that is, those with reduced mobility.
Keywords
Assistive technology, elderly, ageing, bedridden, activities of daily living, disability, rehabilitation devices, rehabilitation robots
* Department of Mechanical Engineering, Federal University
of Santa Catarina, Florianópolis, SC, Brazil
Corresponding author:
Bilal Orun, Department of Mechanical Engineering, Federal
University of Santa Catarina, Campus Universitário –
Trindade, Florianópolis/ SC - 88040-900, Brazil
Email: b_orun@yahoo.com

2. quickly adapt their length to the new position. Short
muscles will lead to functional difficulties associated
with standing, walking, using the upper limbs, etc.3
.
 Pressure sores (bedsores): Due to insufficient blood
supply, the skin dies and an ulcer (bedsore) appears. A
bedsore can easily become infected and be life
threatening3
.
 Respiratory problems: Bedridden persons have relatively
shallow breathing, which can lead to lung infections such
as pneumonia3
.
 Blood circulation problems: The two main blood
circulation problems that bedridden patients might suffer
from are thrombosis and embolism. Both are caused by
a callus (blood clot) which can form in the blood vessels
and lead to tissue damage and even to death depending
on the location at which it occurs3
.
 Bone demineralization: Bone demineralization means
that bones become weaker (they lose the minerals, which
give them their strength). This occurs when the bones do
not receive sufficient mechanical stimulation. A
demineralized bone is more prone to failures3
.
Furthermore, a bedridden person cannot perform the crucial
activities of daily living (ADL) like eating, bathing, toileting,
dressing, etc. These persons are dependent on caregivers due to
reduced mobility. According to Hoenig et al.6
, “personal
assistance” and “technological assistance” are the two basic
modes of coping with limitations that interfere with the ability
to complete ADLs and other tasks.
 Personal assistance refers to help that disabled persons
receive from others, such as a spouse, child, friend, or
paid caregiver. Help from another person does not enable
people to function more independently, but it may reduce
the difficulty experienced when attempting to perform a
given task.
 Technological assistance refers to the use of equipment
(wheelchairs, canes, and walkers, raised toilet seats) to
allow the performance of daily activities.
Assistive technologies come into play to provide
technological assistance to persons with reduced mobility to
enable them to perform ADLs more independently.
Financial cost of caregiving is another main driver for
assistive technologies. Just in USA, there are between 40 – 50
million people living with disabilities that need care according
to the National Institutes of Health.7
Besides the visible cost of
caregiving in caring facilities and hospitals, there is a hidden
cost, which is caused by informal caregiving. The number of
family members providing care is growing as hospitals are
trying to reduce hospital stays and relying more on outpatient
procedures in an effort to cut increasing healthcare costs. 61%
of these (family member) caregivers for elderly and disabled
family members are employed.8
64% of the caregivers of 50+
aged persons reported that occasionally they need to go work
late, leave early and take time off to succeed in caregiving.7
This
caused wage and income loss, even an early retirement. The
impact of income loss is more serious in these cases due
caregiving is an expensive process causing higher out of pocket
health care costs.
Even in hospital care or professional caregiving, caregiving
is financially costly. Due it is a laborious process there are many
injuries for caregivers which results in day loss in work force in
formal caregiving. Assistive technologies help to eliminate
these injuries. For example, using mechanical lifts - one of the
simplest assistive technology - results in significant decrease in
injury rates (from 6.59 injuries to 5.70 injuries annually per 100
full-time equivalents) and the lost day rate (from 32 to 14.9 day
lost per 100 full-time equivalents annually)9
. Furthermore,
according to Anderson and Wiener, personal assistance services
hours decrease 25% by using assistive technology for
indoor/outdoor mobility, bed transfer, and bathing.10
This statistical data show how assistive technology help
caregivers and cut costs as well as making patients more
independent.
Human motion and mobility
Kinematics is the study of the motion of points, bodies and
systems of bodies in mechanics. It is necessary to understand
the science of motion to help bedridden persons. “Kinematics
of Human Motion” written by Vladimir M. Zatsiorsky11
is a
pioneering reference. According to Zatsiorsky, to define a
human body: (1) location or place, (2) orientation or attitude,
(3) joint motion (configuration) or posture have to be known.
The French mathematician and historian of mathematics
Michel Chasles suggested that, in terms of end-point locations,
all motions of a rigid body could be duplicated by means of a
rotation about an axis, together with a translation along that
axis12
. Therefore, (1) location or place, (2) orientation or
attitude and their combinations can be considered as rigid body
motion. Thus, the human body can be defined by two
parameters:
1. Rigid body motion
a. Translation (location, place)
b. Rotation (orientation, attitude)
2. Joint motion
Review of existing solutions
Assistive technologies to help bedridden persons to perform
their basic human body motions are shown in Tables 1 to 5. For
the sake of simplicity, the review of existing solutions was
grouped according to their functions and tables were created for
each group. Features that the reviewed solutions offer in terms
of rigid body motion (translation and rotation on the x-axis, y-
axis, and z-axis) and available joint motion are indicated in the
tables. Rigid body motion and joint motion needs a reference
point to be identified and this reference point is the coordinate
system, which is defined according to Zatsiorsky11
, as shown in
Figure 1. Naming axes is also crucial for cross comparison. In

3. this paper, lateromedial is referred to as the x-axis, longitudinal
the y-axis, and anteroposterior the z-axis.
Figure 1. Coordinate system of a human body13
Well-known rigid body motion consists of translation and
rotation, as mentioned in human motion and mobility section.
However, rotation can also cause translation and to avoid this
undesirable translation the coordinate system is located at the
center of mass of the body and all rotations are executed using
this coordinate system. The reference point to check the
resulting location and orientation is also at the center of mass of
the body to avoid translation caused by rotation. The reverse
situation is not valid, i.e., translation does not cause rotation.
The section ‘wheeled mobility’ is added to the table due
majority of the solutions have wheels to transfer patients, like a
regular office chair. Wheeled mobility is dependent on the
wheel mechanism and the main purpose is to provide planar
motion to allow each user to reach any desired location on a
planar surface.
The column headed ‘Type’ in Tables 1 to 5 shows the source
of the solution, where commercial product is represented by C,
patent by P, and academic papers by A. Commercial products
are available on the market, where some patents are already
commercialized some still stays as an idea and academic studies
are at most in prototype and testing stage. In the column headed
“Joint Motion”, waist refers to articulation between torso and
hip, hip between hip and thigh, knee between thigh and calf and
ankle between calf and foot.
Commercial hospital beds
The role of hospital beds in providing patient comfort is
becoming increasingly important, decreasing already
mentioned side effects of being bedridden, and reducing the
laborious work of the caregiver.
A wide range of options, from manually to fully controlled
high-tech beds, are available on the market. Some important
global players are Linet, Hill-Rom, and Stryker. All of these
hospital beds have wheeled mobility for transferring the
bedridden person to desired location. Due human body motion
can be described as rigid body motion and joint motion and
these beds are developed to provide these types of motion. As
in the case of all commercial products, cost considerations drive
the producers to abandon some features. Thus, depending on
the model and the shelf price, the features vary. The superior
models of the companies are reviewed herein (Table 1) since
they have more functions to investigate.
Linet – Multicare Bed (commercially available)
The Linet – Multicare Bed14
mechanism appears to have six
degrees of freedom (DOF): three to perform rigid body motions
and three for joint motions. The height of the bed can be
adjusted, which is one DOF (z-axis translation). The Multicare
bed can tilt to bring the patient to the head-up or foot-up
Table 1. Review of commercial hospital beds
Name Reference Type
Wheeled
Mobility
Rigid Body Motion
Joint MotionTranslation Rotation
x y z x y z
1 Multicare – Linet 14 C Yes No No Yes Yes Yes No Waist/Hip/Knees
2
Hill-Rom – TotalCare®
Connect Bed
15 C Yes No No Yes Yes No No Waist/Hip/Knees
3 Stryker 16 C Yes No No Yes Yes No No Waist/Hip/Knees
4
Stiegelmeyer – Vertica /
US 4787104 A
17, 18 C & P Yes No No Yes Yes No No Waist/Hip/Knees

4. position, i.e., a second DOF (x-axis rotation). It has lateral
motion to prevent pulmonary complications and help the
caregivers to rotate the patient (which is useful for changing
diapers, bed linen, etc.). The lateral motion (Figure 2) is another
DOF (y-axis rotation). The mechanism also has joint motions
for the waist, hip, and knee joints, to change the orientation of
the back (torso), thighs, and calves of the bedridden person.
Depending on the budget available, the company offers various
features, such as embedded X-ray cassette tray, multiple control
panel (for caregiver, for patient, and foot control for caregiver),
bed exit alarms, security fences to prevent falls, anti-decubitus
mattresses, built-in weighing function, and communication
gadgets. The foot end of the bed is adjustable via an
electromotor to personalize the size for each patient. Some
invasive cardiological procedures can be performed directly in
the bed, for instance, the insertion or localization of temporary
intracardial stimulation, intra-aortic balloon counterpulsation
and catheters measuring hemodynamic parameters in the
pulmonary artery.
Figure 2. Linet Multicare Bed14
Hill-Rom TotalCare®
Connect Bed (commercially available)
The Hill-Rom TotalCare®
Connect Bed15
offers more or less
the same features as the Linet – Multicare Bed and other
commercial products. Totalcare has no lateral motion, i.e., there
is no y-axis rotation, but it can be transformed into a sitting
position, like the Linet – Multicare. This position helps patients
to stand up by supporting them with built in handles. There are
also some additional features, which differ from those of
competing products, such as automatic seat deflate, where the
bed moves into a chair egress position to keep the patient close
to the ground.
Stryker Intouch Bed (commercially available)
The Stryker Intouch Bed16
does not provide lateral motion
but can perform the rest of the motions offered by the Multicare
Bed. Also, it has extra features, including a spoken alarm
advising the patient to “please stay in bed” in 24 different
languages and offers music therapy, differentiating it from other
products.
Stiegelmeyer – Vertica Bed (commercially available)
The Stiegelmeyer – Vertica Bed17, 18
can be transformed into
a total sitting position to help the patient stand up, similarly to
Linet-Multicare and Hill-Rom Totalcare, and also performs the
movements considered to be the market standards. It is aimed
at home care and is designed to be an attractive piece of
furniture which offers a comfortable eating position with a
built-in table in the sitting position.
Most commercial beds, depending on their shelf price, offer
smart data monitoring of the bed motions to analyze the
patient’s needs, recovery, movement requirements, etc.
Solutions for moving patient into/out of bed
One of the most laborious tasks for nurses and caregivers is
moving the patient into/out of bed (transferring and handling,
where transferring means moving a patient from one surface
keeping him/her horizontal to another same height surface and
handling means a more complex movement for instance from
chair to bed) for toileting, showering, etc. This transference
usually occurs from the bed to a stretcher/wheelchair or vice
versa. Besides being laborious, there is also a risk of injury, not
only to the patient but also to the caregiver due to the need for
physical force. Most of the solutions reviewed (Table 2) are still
at the academic research level, although there is one
commercial product in which a conveyor belt system is used to
move the patient into/out of bed.
AgileLife™ Patient Transfer System (commercially available)
At first glance, AgileLife19
seems to be a regular hospital bed;
however, it differs from other models due to its unique service.
It is designed so that bedridden persons can be easily moved
into/out of bed, reducing the need for physical force. This
product (Figure 3) does not provide the movements that
traditional hospital beds offer and it has only two DOF. The first
is the rotation of the lower part (calves) of the bed on the x-axis,
the rotation joint being at the lower end of the bed. This motion
is necessary to support the back part (torso) of the patient during
the transfer. The second DOF is the continuous rotation of the
belt-like system to transfer the patient on the y-axis (y-axis
translation).
Development of a robot to assist patient transfer (academic
research)
Kasagami et al. developed a “Robot to Assist Patient
Transfer”20
, which is a belt-driven system similar to conveyor

5. belts used in industrial plants. The 1-DOF design enables nurses
and caregivers to transfer the patients in a horizontal position,
that is, lying down. The solution decreases the burden on the
nurses and caregivers.
Figure 3. AgileLife patient transfer system19
Design and control of an active mattress for moving bedridden
patients (academic research)
Finger and Asada developed a mechanism for transporting a
bedridden patient in an arbitrary direction while lying
comfortably on the bed21, 22
. A wave-like periodic motion is
generated on a mattress surface by activating the individual coil
springs of which the mattress is comprised. The entire patient
body, or a specific part of it, is moved by this periodic surface
movement.
Maneuvering a bed sheet for repositioning a bedridden patient
(academic research)
Roy et al. developed the marionette bed, which presents a
new method for rolling and repositioning a bedridden patient
using a pair of actuated rollers attached to both sides of the bed
sheet in order to lift and manipulate the patient body23
. This
prevents the development of painful bedsores and of
pneumonia. The novelty of the proposed solution lies in its use
of the bed sheet to cradle and move the patient. The bed sheet
offers the advantages of no stress concentrations and reduced
shear forces during the movement process.
Verticalization solutions with rehabilitation of the lower limbs
Being bedridden and having reduced mobility are associated
with several complications as previously mentioned. One of the
most prominent problems is the instability of the cardio-
pulmonary system due to venous pooling in the lower
extremities when transferring the patient from the horizontal to
the upright position. Any kind of mobilization of these patients
would help to prevent these effects from happening24
.
Verticalization solutions (shown in Table 3) have been
developed to overcome this problem, as well as to rehabilitate
the lower limbs.
BTS ANYMOV (commercially available)
BTS Anymov offers the same movements as the other
hospital beds described above and has an additional
verticalization feature25
. BTS engineering also added a lower
limb rehabilitation mechanism to this product. Since this paper
focuses on the mobility of bedridden patients, rather than their
rehabilitation, the product is analyzed only in terms of human
body motions. The product has apparently six DOF, i.e., three
rigid body motions: z-axis translation (for height adjustments),
x-axis (head-up, foot-up), and y-axis rotation (lateral motion),
and three joint motions: x-axis rotations at the waist and hip
joints and z-axis rotation for both thighs (coupled motion).
Hocoma – Erigo (commercially available)
Erigo is a tilt table with built-in lower limb rehabilitation, as
in the case of the BTS Anymov24, 26
. The product (Figure 4)
Table 2. Review of solutions for moving patient into/out of bed
Name Reference Type
Wheeled
Mobility
Rigid Body Motion
Joint MotionTranslation Rotation
x y z x y z
1 Next Health – AgileLife 19 C Yes No Yes No No No No -
2
Development of a robot to
assist patient transfer
20 A No Yes No No No No No -
3
Design and control of an
active mattress for moving
bedridden persons
21, 22 A No No Yes No No No No -
4
Maneuvering a bed sheet
for repositioning a
bedridden patient
23 A No Yes No No No Yes No -

6. appears to have a 2-DOF mechanism, both of them is for the
rotations on the x-axis: one for the lower part of the body and
one for the upper part. Rotation in lower part of the bed happens
in a four bar mechanism which also cause translation in z-axis
to adjust bed height.
Figure 4. Erigo27
Wheelchair to bed transformation solutions
The principle of the wheelchair to bed transformation
solutions (Table 4) can be seen simply as that of a reclining
chair, which reclines whenever the user lowers the back of the
chair (torso) and raises the front (calves). This solution
commonly appears in daily life, e.g., TV chairs or dentist chairs
for facilitating dentist dexterity. This feature is used for
wheelchairs, to bring the patient into a flat (bed) position in
order to facilitate the transfer between the bed and the
wheelchair.
Simple bed/wheelchair transforming mechanisms
(commercially available)
As the simplest form of bed/wheelchair transformation,
reclining chairs are the ancestors of today’s hi-tech solutions.
Besides motorized options, manual wheelchair/bed
transforming products are still available. While some of them
act like a reclining chair, others become a flat bed. The Invacare
IVC 9000 Jymni Recliner Wheelchair is a commercial example
of a manual solution that provides dynamic reclining from 95
to 160 degrees28
. Motorized examples are specifically
developed to assist patient transfer, and they can totally
transform into a flatbed, for instance, the Bartram H-250 Patient
Transfer System29
.
Patents for Wheelchair to Bed Transformation Solutions - US
189964 A, US 2375151 A, US 2694437 A, US 3284126 A, US
4717169 A, US 4974905 A, US 5230113 A, US 8359685 B2, US
8621691 B1, US 3138805 A, US 4987620 A, US 5555582 A, US
20110030138 A1 (patents – mostly commercially available)
Numerous patents have been issued for bed/wheelchair
transforming mechanisms. “Improvement in folding chairs” -
US 189964 A30
- was the first patent for a bed/wheelchair
mechanism. This mechanism was invented by C. L. Stevens in
1877 and is similar to those referred to today as simple
bed/wheelchair transforming mechanisms. The backrest of the
chair is lowered and the calf segment is lifted for the
transformation into a flat bed (Figure 5). Since this patent,
several others on this subject have been filed. Some examples
are the “Convertible chair”- US 2375151 A (1945)31
,
“Combination wheel chair and stretcher” - US 2694437 A
(1954)32
, “Bed-wheelchair” - US 3284126 A (1966)33
,
“Convertible bed and wheelchair unit” - US 4717169 A
(1988)34
, “Chair bed” - US 4974905 A (1990)35
, “Multiple
position adjustable day night patient bed chair” - US 5230113
A (1993)36
, “Wheelchair with a commode that converts into a
bed” - US 8359685 B2 (2013) 37
, “Chair/bed for the disabled” -
US 8621691 B1 (2014)38
, and many more. Most of the patents
mentioned above are already commercialized.
Table 3. Review of verticalization solutions with rehabilitation of lower limbs
Name Reference Type
Wheeled
Mobility
Rigid Body Motion
Joint MotionTranslation Rotation
x y z x y z
1 BTS – ANYMOV 25 C Yes No No Yes Yes Yes No Waist/Hip/Knees
2 Hocoma – Erigo 24, 26 C & A Yes No No Yes Yes No No Hip/Ankle

7. Figure 5. Improvement in folding chairs – US 189964 A30
Some alternative solutions are also available where the
bed/wheelchair product is designed to be a part of a regular bed
just like the Panasonic – Resyone, as can be seen in the
following section. In this regard, the first patent filed was “Bed-
wheelchair” - US 3138805 A, by Salvatore J Piazza in 196439
.
Unlike most approaches to this solution, Piazza developed the
mechanism as a latitudinal partition, which is easily separated
from the entire bed and can be transformed into a wheelchair.
“Combined bed and wheelchair” - US 4987620 A (1991)40
and
“Convertible bed” - US 5555582 A (1996)41
are slightly similar
where the bed/wheelchair mechanism is a longitudinal part of
the bed, and the remainder of bed, which has is u-shaped, hosts
the mechanism. The patent “Bed”- US 20110030138 A1
(2011)42
is a combination of latitudinal and longitudinal
partitioned beds. The mechanism is a longitudinal part of the
bed, but the docking is conducted from the side, as in the case
of US3138805 A, rather than from the foot edge. Besides from
Panasonic Resyone all the patents that a part of bed transform
to wheelchair are still not commercialized.
Panasonic – Resyone (commercially available)
Assistive technologies for bedridden persons are mostly for
elderly persons and due to the aging world population; the
demand for these technologies is increasing rapidly, especially
in developed countries. Japan is a country confronting an aging
population and its government is promoting research to deal
with this issue. Panasonic has developed a robotic bed called
Resyone (Figure 6), where half of the bed is separable from the
other half and can be transformed into a wheelchair.
However, there is limited data available on the product, i.e.,
newspaper articles and exhibition notes (41st
Home Care and
Rehabilitation Exhibition 201443
) and no technical data can be
cited. The product appears to have a 1-DOF mechanism, with
torso and calf joint motions which are rotations on the x-axis,
apparently involving a coupled motion. The movements could
be achieved by a power screw; the torso is lowered and the calf
area is lifted for transformation from a wheelchair to a bed or
vice versa. This is a big step in terms of the mobility for
bedridden persons, but the mechanism has very limited
Table 4. Review of wheelchair/bed transformation solutions
Name Reference Type
Wheeled
Mobility
Rigid Body Motion
Joint
MotionTranslation Rotation
x y z x y z
1
Simple bed/wheelchair
transforming mechanisms
28, 29 C Yes No No No No No No
Waist/
Knees
2
US 189964 A, US 2375151 A, US
2694437 A, US 3284126 A, US 4717169
A, US 4974905 A, US 5230113 A, US
8359685 B2, US 8621691 B1, US
3138805 A, US 4987620 A, US 5555582
A, US 20110030138 A1
30-42 P Yes No No No No No No
Waist/
Knees
3
Panasonic Resyone – US
20120181779 A1
43, 44 C & P Yes No No No No No No
Waist/
Knees
4 RHOMBUS – MIT 46 A Yes No No No No No No
Waist/
Knees
5 Multifunctional robotic test bed 47, 48 A Yes Yes No Yes No No No
Waist/
Hip/
Knees

8. functions. Joint motions cannot be carried out separately, and
the rigid body motions observed in other products are absent
(except planar motion due to the wheeled mobility).
The “Wheelchair and bed” - US 20120181779 A1 patent filed
in 201244
appears to be similar to the Panasonic – Resyone (in
fact, the original assignee Kawakami is the head of the Resyone
project45
).
Figure 6. Panasonic Resyone49
RHOMBUS – MIT (academic research)
The Reconfigurable Holonomic Omnidirectional Mobile Bed
with Unified Seating (RHOMBUS) is a solution studied by MIT
to overcome mobility problems46
. It is simply a wheelchair/bed
system where the wheelchair can be transformed into a
completely flat position and dock to its predefined location as a
part of the bed. The wheelchair is equipped with a holonomic
omnidirectional vehicle with a ball wheel mechanism resulting
in high maneuverability and the holonomic nature of the vehicle
allows the chair to be docked easily and precisely against a
fixture. The wheelchair was designed to automatically dock to
the water closet, to address one of the crucial issues of
bedridden persons, that is, privacy. The system is equipped with
a teleconferencing facility, enabling the bedridden patient to
communicate face-to-face with a distant caregiver, friends and
relatives.
Multi-functional robotic test-bed (academic research)
Peng et al. developed a very dexterous test-bed for post-
surgical healthcare rooms47, 48
. The piece consists of two beds:
a main bed and nursing bed. The main bed (Figure 7) has a
greater number of DOF than the nursing bed and is composed
of four bedplates to give a perfect fit with human body motion.
The main bed is driven by five linear motors to adjust the height
of the bed and provide the desired rotations for each bedplate
separately on the x-axis, resulting a 5-DOF mechanism.
However, the nursing bed has just one degree of motion, that is,
the lifting-lowering of the torso and thigh as a coupled motion
using a power screw. The height of the nursing bed is fixed.
Both beds are equipped with belts serving as conveyors for
transferring the patient between beds to decrease the laborious
work of the caregivers. Belts are driven via servomotors.
Figure 7. Main Bed48
Lifting transfer solutions
The simplest and most common examples of these products
(Table 5) are patient lifts. According to the U.S. Food and Drug
Administration (FDA), patient lifts are designed to lift and
Table 5. Review of lifting transfer solutions
Name Reference Type
Wheeled
Mobility
Rigid Body Motion
Joint MotionTranslation Rotation
x y z x y z
1 Traditional lifting devices 51 C Yes No No Yes No No No -
2 Robohelper Sasuke 52, 53 C Yes No No Yes Yes No No -
3
Toyota – Patient Transfer
System
53-55 C & P Yes No No Yes Yes No No -
4 Ceiling track lifts 56-58 C No Yes No Yes No No No -

9. transfer patients from one place to another (e.g., from bed to
bath or chair to stretcher). These medical devices provide many
benefits, including reduced risk of injury to patients and
caregivers, when properly used. However, improper use of
patient lifts can pose significant public health risks. Patient falls
from these devices have resulted in severe patient injuries,
including head traumas and fractures, and even deaths50
. In fact,
falls are one of the biggest risks for all products described
above.
Traditional lifting devices (commercially available)
The operating principle of the traditional lifting devices
(conventional mobile hoists) is exactly the same as that of the
forklifts used in production facilities. Patients are lifted by a
mechanism actuated manually or by means of an actuator. After
lifting, patients can be carried to the desired location. The
passive floor lifts from Arjohuntleigh are examples of
commercial products which are battery powered electric lifts
for transferring patients to and from the bed, wheelchair,
shower chair, commode, and etc.51
.
Robohelper Sasuke (commercially available)
Toshiyuki Kita designed the Robohelper Sasuke which is
comprised of two rods, which are connected with a sling as an
aid to nursing activities52
. Sasuke can easily lift the patient from
the prone to the sitting condition. The main function is to lift
the human body to reduce the possibility of injuries during
manual lifting. The mechanism appears to have three DOF,
where one is the z-axis translation to lift the patient. The second
DOF is the y-axis translation of the two rods (coupled motion)
to establish the gap between the rods and subsequently adjust
the stiffness of the sling. After the patient has been lifted and
moved far enough from the bed, he/she is brought to a sitting
position by means of the x-axis rotation, which is the third DOF
of the mechanism.
Toyota - Patient Transfer Assist Robot (commercially
available)
The patient transfer assist robot (Figure 8) has weight-
supporting arms that help support the patient as well as a
wheeled platform which will transport the patient from the bed
to the bathroom or even outdoors for some fresh air and
sunshine54
.
The 2-DOF Simple Self-Transfer Aid Robotic System
developed by Takahashi et al.55
has a mechanism similar to that
of the Toyota – Patient Transfer Assist Robot, from the
technical point of view. The mechanism is equipped with one
rotational and one prismatic joint that allows the saddle to reach
a position where the patient can put his/her belly on the saddle
and the mechanism is then used to lift the patient and transfer
him/her to the desired location, e.g. the bathroom, and return
the patient by reversing the process.
Figure 8. Toyota – Patient Transfer Assist59
Ceiling Track Lifts (commercially available)
Ceiling lifts are another solution, which can reduce the
strenuous work of nurses and caregivers. In ceiling lifts there is
a predefined path, e.g., from the bed to the bathroom. The
patient is lifted by means of a lifting mechanism, which is
actuated by a motor. After lifting, the journey begins and the
route is the predetermined path of ceiling rails. Chhokar et al.56
analyzed the efficacy of overhead lifts in reducing the risk of
injury to the patient and the caregivers. ‘The three-year
economic benefits of a ceiling lift intervention aimed at
reducing healthcare worker injuries showed a reduction in the
frequency and cost of patient handling injuries after the first
year, indicating that ceiling lift programs are a promising
intervention strategy.
The Knueppel Ceiling Track lift57
is a commercial example
of ceiling type lifting. It is described as follows: “Tracking
mounted to the ceiling extends over the bed, tub, commode or
other access point, facilitating transfers to and from a
wheelchair”.
The radial arm system for patient care equipment (US
7065811 B258
) is a robotic arm facilitating the lives of
bedridden persons. Besides functioning as a robotic arm that
delivers objects required by the patient, it also acts as a patient
transfer device. The working principle is same as that of any
lifting device, lifting the patient together with their linen as a
supporting cloth platform.
Miscellaneous solutions
Development of a robotic system for the bed-ridden (academic
research)
Seo et al.60, 61
developed an intelligent bed robot system
(IBRS), which can help the elderly and the disabled to live an

10. independent life in bed. The IBRS is a special bed equipped
with two robot arms and an array of pressure sensors attached
to the mattress. The pressure distribution on the mattress is used
to estimate the pose of the patient, and the robot arms provide
appropriate assistance. The Korea Advanced Institute of
Science and Technology has also patented a proposed solution
under the patent number US 20080078030 A162
.
JACO (commercially available)
JACO is a 6-DOF robot arm which is also used as a
rehabilitation tool for disabled persons63,64
. The JACO Rehab
Edition is an assistive robot arm for the upper body of disabled
persons in a power wheelchair. It can be integrated with almost
all models and configurations of power wheelchair controls. Its
low weight (5.7 kg) means that it will not affect the stability of
the power wheelchair. Its hand, with its three flexible fingers,
can easily and safely handle everyday objects with maximum
payloads of up to 2.5 kg mid-range and 1.5 kg full extension.
This kind of robot arm for gripping can also be embedded in
robotic bed solutions, enabling bedridden persons to perform
their ADLs.
Assistive Technology for Self-Feeding (academic research)
Feeding robots are developed to make bedridden people eat
without support of caregivers. Eating is one of the main ADLs
where any human being eats at least 3 times a day. According
to a study done by DTI Robot Technology 16 minutes and 44
seconds of staff assistance are saved per meal, when an eating
assistance machine is used.65
Some examples of eating
assistance machines are Novel Assistive Robot for Self-Feeding
developed by Korea National Rehabilitation Research Institute
and Korea National Rehabilitation Center, Handy1, Winsford
feeder, Neater Eater, My Spoon, Meal Buddy, Mealtime Partner
Dining System.66
Neater Eater is now commercially available.
67
Toyota – Human Support Robot (HSR) (commercially
available)
The Human Support Robot (HSR) is being developed to
assist people in their everyday activities54
. The arm has a simple
gripper to pick up objects, such as pens and TV remotes, while
thinner hard-to-grasp objects like paper or cards can be lifted
off the floor using a small vacuum installed in the hand. The
user can also voice command the robot to retrieve objects from
boxes and shelves. HSR can also be used for remote operation
"telepresence", which would allow caregivers and family
members to communicate with the robot's owner over Skype or
other services, by means of a tablet dock on top of its head.
Figure 9. Human Support Robot (HSR)68
Care-O-Bot 3 (academic research)
Graf et al.69
developed a solution for technical aids for elderly
and handicapped people able to navigate autonomously in
indoor environments, to be used as an intelligent walking
support, and execute manipulation tasks. The walking aid
module is based on sensors in the walking aid handles and on a
dynamic model of conventional walking aids. Care-O-bot®
3
has been presented to the public on several occasions where it
distributed drinks to the visitors of trade fairs and events.
Recently, Fraunhofer IPA launched Care-O-bot 4, which is
an improved version. It is a complete service robot with up to
31 DOF and two spherical joints, providing an exceptional
workspace that is completely covered by sensors. The spherical
joints allow for roll-pitch-yaw movements of the torso and
head, empowering the robot to perform a wide range of body
gestures. Touchscreen, microphones, speakers, and head
cameras enable human robot interaction solutions based on a
graphical user interface and gesture recognition. This service
robot will serve almost anywhere, and is appropriate for the
home, industrial, and service usage. It can be used to perform a
variety of household tasks, for example, to deliver food and
drinks, to assist with cooking or cleaning, to support patients in
healthcare institutions, to deliver orders in restaurants, to
provide reception and room service in hotels or for
entertainment. It could also be used in industrial plants, for shelf
picking and for commissioning in warehouses or the loading
and unloading of machines in manufacturing environments70
.
RIBA (academic research)
Mukai et al.71
developed a robot named RIBA with human-
type arms which is designed to perform heavy physical tasks
requiring human contact, and transfer a bedridden person from
a bed to a wheelchair and back.
To use RIBA in changeable and realistic environments,
cooperation between the caregiver and the robot is required.
The caregiver takes responsibility for monitoring the
environment and determining suitable actions, while the robot

11. undertakes hard physical tasks. The instructions can be
intuitively given by the caregiver to RIBA through tactile
sensors using a newly proposed method named tactile guidance.
Figure 10. RIBA71
Yurina (commercially available)
Yurina is another solution, which is similar to RIBA, with
two humanlike arms and a wheeled base72
that can carry
bedridden patients and transfer them to other locations, as in the
case of RIBA. It has an extra bed mechanism that can be
embedded into the robot arms. These arms appear to have three
DOF, by means of two rotation and one prismatic joint. Both
arms are connected to the bed where one arm is connected to
the hip segment and the other is connected to the torso segment.
The motion of the calf segment of the bed is coupled with the
torso segment motion, that is, when the torso is lifted, the calf
is lowered inversely. The rotation joint at the end of these arms
provides rigid body motion, i.e., rotation on the y-axis, referred
to as lateral movement in the hospital bed market.
HOSPI-Rimo®
- Panasonic (commercially available)
Hospital staff members are increasingly burdened with
additional tasks, such as watching over patients and patrolling
to look out for roaming patients or suspicious individuals, due
to the aging population. Panasonic has created a service robot
aimed at decreasing this workload. Hospi-Rimo is an automatic
medication delivery robot, which is used to sort medications
and transport them to nurse stations. It also lets patients connect
with and communicate with their doctors, family or friends, etc.
from a long distance73
. It is equipped with four cameras and
images taken from these cameras are mapped to create a 3D
map of the environment. The user can zoom in anywhere on this
3D map. Human detection and recognition is another function
of Hospi, and it can classify individuals as doctors, nurses,
patients or others74
.
Discussion
As previously mentioned, the increase in the aging
population will boost the development of assistive technologies
and the statistics and forecasts of International Federation of
Robotics75
show the same trend for assistive robots. According
to the Executive Summary of World Robotics 2014 - Industrial
Robots and World Robotics 2014 Service Robots75
, handicap-
assistance robots have boomed in recent years, as anticipated.
In 2013, around 700 robots were sold, up from 160 in 2012 (an
impressive increase of 345%). The predictions indicate a huge
leap for assistance robots. Sales of robots for the elderly and
handicap assistance are forecast to be around 12,400 units in the
period of 2014-2017. This market is expected to increase
substantially within the next 20 years.
Conclusion
This paper provides a broad review of assistive technology
for bedridden persons, an area which is continually advancing,
with ever increasing numbers of specialists performing research
in this area. Engineers are collaborating with medical experts,
physiotherapists, and caregivers to understand the needs of
bedridden persons so that they can develop mechanisms which
can solve their problems and improve the quality of their lives.
The aim is to develop more efficient, user-friendly,
reconfigurable solutions that can provide more specific
assistance with more functions in a single product. The
functions of the existing solutions can be united to develop
brand new solutions. The purpose of this review is to enter
assistive technology area as a research topic. Due to the first
attempt, literature review is done as widely as possible. The
idea was to see main segments and omit too many versions in
the same segment. Domestic servants i.e. hospital beds are kept
more detailed due it was the starting point of our project that
aims improving the reduced mobility of bedridden persons at
the beginning by basic human motion. Grippers, feeders,
rehabilitation tools (Continuous Passive Motion – CPM) will be
upcoming project that can be embedded to the first project
mentioned above which we see as a reconfigurable platform.
Declaration of conflicting interests
The authors declare that there is no conflict of interest.
Funding
The work conducted was partially supported by the Brazilian
Government Agency: Coordenação de Aperfeiçoamento de
Pessoal de Nível Superior (CAPES).

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