Greg R. Luecke

Iowa State University
Department of Mechanical Engineering
2096 Black Engineering Building
Ames, IA 50011


(515) 294-5916 (Office), (515) 294-3261 (Fax),



Virtual Environments.


Force feedback, virtual interface, robotic exoskeleton, haptic device


The objective of the research in this project is to develop a haptic interface system that allows force interactions with computer-generated virtual reality graphical displays. This system is based on the novel application of electromagnetic principles to couple the human hand with a robotic manipulator. The robot manipulator provides a foundation for providing absolute force feedback from the virtual world to the human operator. The use of a robotic manipulator also allows a wide range of hand motion and supports the weight of the position tracking and force generation equipment. The use of electromagnetic principles to generate Lorenz forces between the hand and robot provides the capability for high bandwidth, accurate, and repeatable force control. Using this approach, the forces are transmitted between the robot and the human without using mechanical attachments to the robot.

The development and interfacing of the mechanical hardware used to implement the force feedback system is a major aspect of this research. A prototype robotic exoskeleton has been developed to track the human hand and hold powerful magnets fixes relative to wire coils attached to the hand. Tracking of the hand is achieved using optical sources and sensors, and forces are generated by sending current through the coils. A six degree of freedom robot manipulator is planned for use as the motion platform, carrying the exoskeleton device near the hand of the user and providing reactions for the electromagnetic forces. Virtual forces are computed from the interactions between models of objects and the user's hand in the virtual environment and transmitted to the human by energizing electrical coils attached to the finger tips of the user.

The system under development will provide the human user with a unique interface to the computer generated virtual world. This interface will apply computer generated forces to the digits of the human operator's hand according to an arbitrary model residing in the computer program. Although the system will be developed for contact and manipulation of realistic objects in a virtual environment, it will also allow humans to interact with computer graphic images that are not based on physical systems. Manipulation of mathematical data and interactions with virtual design prototypes will open new avenues of human-computer interaction.


Luecke, G. R., Winkler, J., "A Magnetic Interface for Robot-Applied Virtual Forces", Dynamic Systems and Control, DSC-Vol 55-1, 1994, pp 271-276.


The use of computer-generated imagery and interactive scenes for creating virtual environments is being applied in the areas of medical research, manufacturing, data analysis, and entertainment. Various methods have been used to provide interactive interfaces with the graphical environment. The ability feel interactions with the virtual environments is known as haptic feedback. Development of force feedback between humans and virtual environments is a necessary next step to enhance the feeling of immersion within VR environments and to allow natal interaction with the computer model of the environment. Several approaches are under way to provide a physical connection with the graphical scene, including the use of the master end of a robotic teleoperator, mechanical attachments made directly to the digits, and exoskeleton gloves worn to provide external forces to the human. Electromagnetic interfaces have also been used to allow force interactions through mouse and joystick interfaces. Extension of these principles to allow the application of electromagnetic forces between a robot and the human involves the issues of robot tracking and control, force control in cooperating robotic systems, stability of sampled data systems and real-time control.


Adachi, Y. 1993 "Touch and Trace on the Free Form Surface of Virtual Object", IEEE Virtual Reality Annual International Symposium, VRAIS, '93 September 18-22, 1993, pp162-168.

Bergamasco, M., 1993, "Theoretical Study and Experiments on internal and External Force Replication" IEEE Workshop on "Force Display in Virtual Environments and its Application to Robotic Teleoperation", May 2, 1993, Atlanta, Georgia.

Burdea, G., J. Zhuang, E. Roskos, D. Silver, and N. Langrana, 1992. "A Portable Dexterous Master with Force Feedback", Presence-Teleoperators and Virtual Environments, MIT Press, Vol1 (1), pp. 18-29.

Colgate, J. E., Grafing, P. E., Stanley, M. C., and Schenkel, G., 1993, "Implementation of Stiff Virtual Walls In Force-Reflecting Interfaces". IEEE Virtual Reality Annual International Symposium, VRAIS, '93 September 18-22, 1993, pp 202-208.

Massie, T. M., and J.K. Salisbury, "The PHANToM Haptic Interface: A Device for Probing Virtual," Dynamic Systems and Control: vol. 55-1, 1994

Shimoga, K. 1993 " A Survey of Perceptual Feedback Issues in Dexterous Telemanipulation: Part II Finger Touch Feedback" IEEE Virtual Reality Annual International Symposium, VRAIS, '93 September 18-22, 1993.


3. Other Communication Modalities.

4. Adaptive Human Interfaces.

5. Usability and User-Centered Design.


Providing the human being with the capability to manipulate graphical images using natural motion and touch will be extremely important as a means of interacting with computer models. Augmenting use of surface and volumetric display of abstract information with force feedback can provide new paths for intuitive solutions to these problems.