EFFECT OF FRAME RATE AND FORCE FEEDBACK ON VIRTUAL OBJECT MANIPULATION

Research on virtual environments (VE) produced significant advances in computer hardware (graphics boards and i/o tools) and software (real- time distributed simulations). However, fundamental questions remain a bout how user performance is affected by such factors as graphics refr esh rate, resolution, control latencies, and multimodal feedback. This article reports on two experiments performed to examine dextrous mani pulation of virtual objects. The first experiment studies the effect o f graphics frame rate and viewing mode (monoscopic vs. stereoscopic) o n the time required to grasp a moving target. The second experiment st udies the effect of direct force feedback, pseudo-force feedback, and redundant force feedback on grasping force regulation. The trials were performed using a partially-immersive environment (graphics workstati on and LCD glasses), a DataGlove, and the Rutgers Master with force fe edback. Results of the first experiment indicate that stereoscopic vie wing is beneficial for low refresh rates (it reduced task completion t ime by about 50% vs. monoscopic graphics). Results of the second exper iment indicate that haptic feedback increases performance and reduces error rates, as compared to the open loop case (with no force feedback ). The best performance was obtained when both direct haptic and redun dant auditory feedback were provided to the user. The large number of subjects participating in these experiments (over 160 male and female) indicates good statistical significance for the above results.