Haptic Device Application in Persian Calligraphy Misagh Mansouri Boroujeni 1 , Ali Meghdari 2 School of Science and Engineering Sharif University of Technology International Campus, Iran misagh_mansouri@kish.sharif.edu 1 , meghdari@sharif.edu 2 Abstract— The Haptic device is capable of interacting dynamically with the operator by the forces it can exert on human’s hand. Controlling the haptic device and constraining it through the desired trajectory is the common task in the most of the training systems. Haptic interface application in virtual Persian handwriting learning system is investigated in this paper. Two different modes of learning is investigated: The full guidance mode, guides the user to follow a pre- recorded trajectory by applying proper force to operator’s hand; whereas in partial guidance, combination of haptics and visual feedback guides the operator and prevents deviation from the desired trajectory. Keywords- Haptics, Virtual Training, Trajectory Control, Calligraphy I. INTRODUCTION The idea of haptics comes from teleoperation. In the idealized teleoperator system, the infinitely rigid, massless stick was used as a tool for remote manipulation of objects or environment [1], [2]. By satisfying these preconditions the force exerted on the tip of the stick in the distance could be exactly felt on operator’s hand. An operator would feel the object being poked at distance as if the stick did not exist. The force- feedback idea was defined to replace the stick by a haptic mechanism consist of sensors and actuators. The remote object was also replaced by the virtual object in the computer [3]. Haptic is an interdisciplinary branch of knowledge which has brought physics, robotics, computational geometry, neurophysiology, biomechanics, and computer science together in the study of human touch and force feedback with the external environment [4]. Researchers categorize the rapidly increasing research of haptics into four subareas: human haptics, machine haptics, computer haptics, and multimedia haptics. Human haptics deals especially with the human sensory systems like joints, muscles, bones and nerves to find out the optimal interaction with the human user. The machine haptics involves designing, constructing, and developing mechanical devices or robotic manipulator that can replace or augment human touch. Computer haptics deals especially with rendering the forces, torques and velocities, which can lead to develop different applications. Multimedia haptics involves integrating haptics with audio, visual and other types of media. Realization of human skill by robots has been studied in [5]; however, their objective was to automate the skills, not to display the teacher’s skill to human student. In the late 90’s, virtual reality made it possible for users to feel as if they were really surrounded by a virtual world built by computer software [6]. Different haptic devices have been developed to provide the feeling of touch and forces to the operator in the virtual world [7]-[9]. Various control algorithms for displaying dynamics of virtual objects have also been studied [10], [11]. Some tasks like sensorimotor skill require a sequence of operations. An amateur can learn how to imitate such tasks by following the expert operation; however, there are certain learning tasks, in which dynamical interaction with the trainee is required [12]. Examples of tasks where physical guidance takes place are in learning handwriting, medical simulators [13], painting or sculpting techniques [14], and sports [15]. Haptic calligraphy systems have been studied so far in [16], [17]. Instead of a teacher holding the students’ hands the haptic device was replaced for the tasks such as learning to write Persian characters in this work. It can not only decrease the time consumption but also provides the equivalent opportunity for all trainees to learn under the same instructions. In the present paper two methods have been used for learning the Persian calligraphy. In the Persian alphabet, most of the characters have various curvatures and this reason makes it hard for most of beginners to accomplish this process. Moreover most of the people with poor handwriting complain about their teachers in the first years of their education. These factors justified the author to make use of this robotic device for this application. This work is not only unique because it is used for Persian handwriting system, but also because of the combination of methods which were used for learning. In the first mode the reference Persian trajectory of the characters is available and the user is constrained to move through this path. The force is zero while the trainee follows the right path and it will be increased by the deviation of the user from the defined path. In the second mode the user will experience the full guidance mode in which the forces and the position of the haptic device guide the user to track the pre-recorded path. It resembles the teacher holding the student’s hand in the first phase of the learning, while student tries to record and to imitate exactly the instructor’s trajectory. International Conference on Computer and Automation Engineering 978-0-7695-3569-2/09 $25.00 © 2009 IEEE DOI 10.1109/ICCAE.2009.55 160