J. Software Engi neeri n g & Applications, 2010, 3, 990-997
doi:10.4236/jsea.2010.310116 Published Online October 2010 (http://www.SciRP.org/journal/jsea)
Copyright © 2010 SciRes. JSEA
Design and Development of Virtual Objects to be
Used with Haptic Device for Motor Rehabilitation
Jatin B. Maniya, Pushparaj Mani Pathak, Bhanu Kumar Mishra
Mechanical and Industrial Engineering Department, Indian Institute of Technology, Roorkee, India.
Email: pushpfme@iitr.ernet.in
Received August 2nd, 2010; revised August 25th, 2010; accepted Se pte mbe r 2 nd, 2010.
This paper presents design and development of virtual objects to be used with haptic device PHANTOM Omni for motor
rehabilitation by incorporating visual and haptic feedback. Developed predominantly for augmentation of motor skill of
patient, the objects could also be used for teaching and enhancing writing skill of children. The virtual objects include
English alphabets, numbers, string and mazes, and games. The scheme has been evaluated on children from 11 to 14
years age. The ex pe rim ent gives good results.
Keywords: Haptic, Motor Rehabilitation, Virtual Environment
1. Introduction
Haptic is derived from the Greek verb “haptesthai”
meaning “to touch” and it refers to the science of touch
and force feedback in human-computer interaction. As
haptic devices are evolving and getting cheap er and more
compact in size options are explored by the researchers
for their use in medical applications. Haptic device pro-
vides an excellent addition to virtual environment due to
the force feedback and tactile input/output when it is
used for rehabilitation of patients suffering with motor
disorder. This property also helps the children who are
learning to write, who otherwise get this information
from teacher’s han d wh en he/she holds their han d.
Generally, stroke sufferer loses the skill of writing and
they are unable to write again. From literature it is ob-
served that little work has been carried out on enhancing
writing skill of patient recovering after stroke. Many
stroke victim state loss of handwriting ability as one of
their biggest disabilities compared to other injury [1]. In
1998, Prisco, Avizzano, Calcara, Ciancio, Pinna and
Bergamasco [2] have presented an immersive Virtual
Environment (VE) including visual, auditory and haptic
feedbacks, which had been designed specifically to help
in recovery or improve the motor dexterity of the arm
and hand of patients affected by motor disorder. They
created kitchen base environment in which subject has to
execute task like burning stove, putting coffee pot on
stove etc. and they got satisfactory result when tried on
patient. During the same time Hen mi and Yoshikawa [3]
developed virtual calligraphy system to transfer skill of
teacher to student. They concluded that the student’s po-
sition and force trajectories resemble closer to those of
the teacher’s as the exercise advances. Gillespie,
O’Modhrain, Tang, Zaretzky and Pham [4] developed
virtual environment, which can demonstrate certain ob-
ject manipulation techniques. Although average per-
formance time for the experimental groups did not im-
prove faster than that of the control group, the optimal
strategy was successfully communicated to the experi-
mental groups. Pernalete, Yu, Dubey and Moreno [5] has
developed an assessment and training procedure that re-
sult in improving handwriting taking advantage of the
force feedback provided by the haptic device, incorpo-
rating inertia and viscosity effects to decrease the tremor
in the hand as well as to stimulate the muscles. Teo,
Burdet and Lim [6] introduced a virtual teaching system
for Chinese ideograms that guides movement by haptic
and visual feedback. It resulted in improvement of per-
formance, in particular for beginners learning Chinese
writing with a pen. Learning was evaluated by consider-
ing accuracy and speed of writing. Feygin, Keehner and
Tendick [7] inv estigated use of haptics for sk ills training.
Their study indicated that haptic guidance is effective in
training. The performance was improved in terms of po-
sition, shape, timing, and drift. In 2005, Pemalete et al.
[8] performed a test on a force-reflecting haptic interface
device, PHANTOM with the GHOST SDK Software.
Design and Development of Virtual Objects to be Used with Haptic Device for Motor Rehabilitation991
They used these devices to improve the hand eye coor-
dination problem of children. In 2005, Mullins, Mawson
and Nahavandi [9] have developed a method of control-
ling a user’s hand through the process of writing. They
introduced Proportional Differential (PD) controller that
decreases the overshoot and reduces settling time to ac-
ceptable boundaries in PHANTOM. Grantner, Gottipati,
Pernalete, Fodor and Edwards [10] have developed an
intelligent decision support system for eye-hand coordi-
nation assessment which is based on fuzzy logic algo-
rithm. It takes decision on whether subject should be
allowed to move to next stage or not based on his/her
previous performance. In 2007, Mansour, Eid, and Sad-
dik [11] presented a multimedia system designed to fa-
cilitate learning of alphabetical handwriting of various
languages by incorporating visual, auditory, and haptic
feedback. Gouy-Pailler, Zijp-Rouzier, Vidal and Chêne
[12] have represented a system consisted of a haptic pen
and computer generated virtual environment. This system
was used to teach the children, especially visually im-
paired children. This system was specially designed to
teach geometric lessons. Subjects were asked to regener-
ate the shapes immediately after training. Experiments
performed on them have shown impressive results, spe-
cifically in case of totally blind subjects. Palluel-Germain
et al. [13] have developed a system incorporating a
visuo-haptic device ‘Telemaque’ to increase the fluency
of handwriting production of cursive letters in kinder-
garten children i.e., before formal handwriting learning
begins. Rassmus-Grohn, Magnusson and Efiring [14]
presented the evaluation of an audio-haptic editor and
explorer for virtual 2D relief drawings that allow visually
impaired users to create and explore graphical images. In
2007, Kayyali, Shirmohammadi, Saddik and Lemaire [15]
presented a system that uses haptics, in conjunction with
virtual environments, to provide a rich media environ-
ment for motor rehabilitation o f stroke patients. The sys-
tem also provides occupational therapists with a hu-
man-computer interface that allows for easier set-up,
more facilitated interaction with the system, and provides
a more autonomous means for the progression of the pa-
tient. The system had been modified, after thorough
analysis by a group of experienced occupational thera-
pists. In [16], Bayart, Pocheville and Kheddar have pre-
sented a progressive guiding system designed as a soft-
ware module for the framework I-TOUCH using simple
XML code. They have built features like fully, partially
and no guidance from haptic device, PHANTOM Omni.
Then from the experiments carried out over three groups,
they concluded that the one group given partial haptic
help, perform well compared to other two.
This work presents virtual environment where objects,
numbers, words and games have been created in open
platform. The earlier work reported has been related with
Chinese character [6]. Here we have created virtual ob-
jects that comprises of complete English alphabets, Eng-
lish numerals from 0 to 9, English words, and games.
These virtual objects are interfaced with SensAble
PHANTOM Omni haptic device. Presented system can
provide training to enhance writing skill of motor stroke
patients and children. This method of haptic training has
the potential to stimulate re-learning in the brain of
stroke victim. Alphabets, numbers and full words have
been created with aim of increasing the learning ability
whereas maze has been created to improve coordination
skill in subjects. A ball tracking game has been created
with aim of increasing the concentration of subjects.
These objects have been created based on a study carried
out on motor disordered patients. To validate the idea
experiments have been carried out on subjects aged
11-14 years. The experimental results clearly indicate
improvement in the learning ability of the subjects. The
principal contribution of this work is logical creation of
virtual objects which have been linked with PHANTOM
Omni haptic device and testing of these objects on sub-
jects for evaluating learning level.
2. Brief Description of Haptic PHANT OM
The PHANTOM Omni model is the most cost-effective
haptic device available today. Three degrees of force, in
the x, y and z, direction are achieved through motors that
apply torque at each joint in the robotic arm. The position
and orientation of the pen are tracked through encoders
in the robotic arm. Figure 1 shows setup for rehabilita-
Figure 1. Haptic rehabilitation setup with PHANTOM
Omni and computer.
Copyright © 2010 SciRes. JSEA
Design and Development of Virtual Objects to be Used with Haptic Device for Motor Rehabilitation
3. Result of Study on Motor Disordered
Some subjects were studied to find major difficulties
faced by them. This information was used to create vir-
tual environment that can be used for augmentation of
their motor skills. Table 1 shows the details of the sub-
jects, difficulties faced by them and the reason for the
difficulty. Conclusion from Table 1 is that motor disor-
dered patients suffer from uncontrolled hand movement,
due to which they cannot write properly.
4. Design of Virtual Objects for Training
The system consists of alphabets, numbers, string, maze
and game. Presented system has been designed to give
partial guidance to the subject. This system has different
exercises on alphabets and numbers which are partially
guided. Here partially guided means object will not react
until subject is moving his hand within range of
pre-specified path. When it tries to move outside of ob-
ject, system will exert force on stylus and will keep it in
range only. Thus, the system is neither fully guided nor
fully free. To attain this feature in letters, we created 3-D
model of letters which consists of walls.
In present system, Open Graphic Library Utility Tool-
kit (GLUT) is used for graphical presentation on screen.
Haptic Device Application Programming Interface
(HDAPI) provides low-level access to the haptic device.
It also enables haptics programmers to render forces di-
rectly, offer control over configuration, the runtime be-
havior of the drivers. Haptic Library Application Pro-
gramming Interface (HLAPI) provides high-level haptic
rendering and allows significant reuse of existing
OpenGL code and greatly simplifies synchronization of
the haptics and graphics threads.
Table 1. Difficulties faced by disordered subjects.
S.N. Subjects Type of difficulty Reasons
1 Subject A;
Age-14 Years
Judgment about space and
time, poor handwriting,
language impairment
Motor disorder
from childhood
2 Subject B;
Age-19 Years
Uncontrolled body
movement, could not stand
Motor disorder
developed after
3 Subject C;
Age-53 Years
Could not perform normal
domestic work, could not
write Stroke victim
4 Subject D;
Age-35 Years Drop things frequently,
awkward gait pattern
Motor disorder
developed after
5 Subject E;
Age-70 Years
Problem with fine motor skill
like cutting food, getting cup
of tea, freque nt fatigue
Faced motor
disorder after 65
4.1. Alphabet and Number System
With the help of alphabet and number system virtual ob-
ject, one can learn to write alphabet and numbers. The
letters has been created in PRO/ENGINEER (Pro/E),
solid modeling software. Using this model along with
OpenHaptic Toolkit, we created scenario in which one
can feel the shape of particular letter and move the cursor
along with it. As the subject moves his hand through the
shape, the stylus will not exert any reaction force on
subject hand. But when stylus tries to run out of the wall
of letter, subject will feel reaction force and it could not
move beyond that limit. This ensures that subject hand
remains within certain limit and thus the subject motion
is neither free nor fully constrained. We also aided visual
feedback through picture, which helps subject to re-
member used letter and correlate that picture to specific
word. The flowchart used for creation of a letter is shown
in Figure 2. First of all letters or numbers are modeled in
Pro/E environment. The created file is in .prt format.
This created file is converted in to .3ds format. Then
model is imported in visual C++ environment. The prop-
erties of object like mass, stiffness, damping, friction etc.
are set. Add picture of the object as visual aid. Also
spelling of the object is added. The created alph abet Q is
shown in Figure 3.
Modeling of letters and
numbers in pro/E (*.prt)
Convert to *.3ds format
Call in VC++ programming
Set properties of object like mass,
stiffness, damping, friction, etc.
Enable haptically
Add visual aid (picture) and its
Figure 2. Flowchart for alphabet.
Copyright © 2010 SciRes. JSEA
Design and Development of Virtual Objects to be Used with Haptic Device for Motor Rehabilitation993
Creation of numbers is similar to alphabets. Its win-
dow contains a number and its spelling printed on a
sphere. The snapshot of developed object is shown in
Figure 4. The algorithm followed for its construction is
similar to that used for alphabets.
4.2. String
After one gets practice on letters and number system, the
next stage is to learn group of letters i.e. words. So, next
set of exercise can be practice on strings. String is con-
structed using constrained motion scenario. The flow-
chart used for creation of string is shown in Figure 5.
The screen shot of created string is shown in Figure 6.
4.3. Constrained Wall Maze
One can practice on constrained maze exercises and can
build ability to take decision and follow the path. The
created virtual object will not react if subject moves his
hand on pre-defined path, but when he/she tries to devi-
ate from it, he/she feel that the motion in that direction is
constrained. Thus in this exercise subject could not move
his hand in any direction but only pre-specified way. To
Figure 3. Alphabet exercise .
Figure 4. Letter exercise.
I nitialize s GLUT for displaying a simple
haptic scene (string)
Initialize the scene handles.
Init ia lize both open GL and HL.
Initia lize the HDAPI
Use the current openGL viewing
tran sformat ion to show string and cursor
Display the sc ene of latest snapshot of stat e
En able all objects hapti cally
Deall o cate any state and clean up when exit
Set up general openGL renderin g properties : light ,
depth b uff ering , et c.
GLUT callback for redra wing the view
Figure 5. Flowchart for string.
Figure 6. Word (string) exercise.
Copyright © 2010 SciRes. JSEA
Design and Development of Virtual Objects to be Used with Haptic Device for Motor Rehabilitation
reach at finish point from start point, subject has to take
many decisions about the path which he has to choose to
reach at end point. This exercise will help to augment
decision making skill of subject. The flow chart used for
creation of maze is similar to that used for string. The
created object is shown in Figure 7.
Another object called wall maze is created using basic
shape-block. The purpose of this maze system is to com-
pare it with constrained maze and to see which one is
more effective. The increase level of difficulty of maze
makes it difficult for the subject to reach the end point.
Figure 8 shows the flowchart used in creation of the ob-
ject. Figure 9 shows the snapshot of third level in maze
exercise. The difference between maze of Figure 7 and 9
is that in Figure 7 cursor is guided along the wall of the
maze whereas in Figure 9 cursor is guided to move be-
tween the walls of the maze.
4.4. Game
The virtual objects are created to simulate game like en-
vironment. The subjects can be asked to play these
games. These will be a good exercise for them. In these
exercises, the ball moves on screen randomly and subject
has to move his hand along with it to make sure that
contact is not lost. As difficulty level increases, th e speed
of ball increases, so, the chance of lose of contact in-
creases and subject has to take relatively quick decision
to keep touching the ball. The snap shot of created game
is shown in Figure 10.
4.5. Graphic User Interface (GUI)
To access all the exercises from one platform, graphic
user interface (GUI) has been developed. Through GUI
one can launch any exercise by clicking on desired ap-
plication. But before laun ching any applicatio n, one must
make sure that previous one is closed. This is because
thread used for previous application must be de-allocated
Figure 7. Constrained maze exercise.
GLUT callba ck for redra wing the vi ew
Initializes GLUT for displaying a maze
Set camera angle and view properties and d ef ine box
properties like height, width etc.
Initialize the HDAPI
Draw boxes using function call with given
stiffness, damping and static and dynamic friction
by passing coordinate and height
Draw invisible wall (upper and lower)
Enable all objects haptica lly
Exit state and clean up
Figure 8. Flowchart used for creation of wall maze.
Figure 9. Wall exercise.
Copyright © 2010 SciRes. JSEA
Design and Development of Virtual Objects to be Used with Haptic Device for Motor Rehabilitation995
Figure 10. Game exercise.
to use it with new application. Figure 11 shows GUI for
develope d system.
5. Experimental Validations on Subjects
Experiments were conducted on four subjects of age
group 11-14 years as subjects from this age group were
readily available. In alphabet and number exercise, they
were asked to move their hand along predefined path
which create letters or number using wall scenario.
Figure 12 shows time taken by one subject to com-
plete the different letters of the alphabet. This Figure
shows results for introduction, training and testing. It is
seen that when the test is introduced to subject, he takes
more time as compared to during training and testing.
This clearly shows the improvement in writing speed of
the subject. After getting practice on individual letter,
subjects were given exercise to write words. The average
time taken to complete different words for different sub-
jects is shown in Figure 13.
Here also we see considerable improvement in the per-
formance of the subjects in terms of speed of writing
Figure 11. Graphic User Interface (GUI).
Figure 12. Time taken to complete different letters by one
Figure 13. Average time taken by subjects to complete dif-
ferent word s.
Figure 14 shows results for writing of numbers. Here
also we see that subjects have shown improved perform-
ance in writing numbers after they got training on this
system. In maze exercise, subjects had to take decision
and move their hand through feasible path from many
available paths to reach at end point from start point.
Figure 15 shows the performance of subjects when they
performed on wall and constrained maze.
We observe from this Figure that constrained maze
requires comparatively less time as compared to wall
maze to complete the task of traveling from start point to
end point. Figure 16 shows performance of subjects af ter
training on game object. We observe improvement in
subject performance after getting training on designed
Copyright © 2010 SciRes. JSEA
Design and Development of Virtual Objects to be Used with Haptic Device for Motor Rehabilitation
Figure 14. Average time taken by subject s to complete num-
Figure 15. Average time taken by subjects to complete dif-
ferent maze level.
Figure 16. No. of times contact loss from ball.
system of game. As they practice more on game scenario,
they are less like to lose contact with randomly moving
sphere on the screen.
6. Conclusions
This work presented the idea of use of virtual objects to
improve the motor skill of the patients suffering from
motor disorder. To validate the idea experiments were
conducted on children aged 11-14 years. It is revealed
that after being introduced to system, they adapt it rap-
idly and their skill improved and also time taken to ac-
complish the task has been reduced significantly. This
system has potential to train motor disordered patients
and stroke patients. The improvement in performance of
the children in term of speed by which they created the
object is encouraging. This system can be further im-
proved by generalizing the strings and by incorporating
full sentences. The game scenario also can be added
which provides good exercise.
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