Progressive shared control for training in virtual environments

Virtual environments (VEs) with haptic feedback not only provide a safe and versatile practice medium for many manual control tasks, but also promise to improve the efficacy of manual skill training with the addition of haptic guidance. However, haptic guidance schemes such as shared control may be detrimental since such schemes actively interfere with the coupled system dynamics, thereby causing participants to experience task dynamics that are altered from those of the real task. Therefore, this paper proposes a progressive approach to guidance for training in virtual environments. This progressive guidance scheme adjusts its control gains based on participant performance, aiming to expose the performer to an appropriate amount of haptic guidance throughout training. Long term training experiments were conducted for an under-actuated target-hitting manual control task. The experimental results compare the efficacy of the novel progressive haptic guidance to two common fixed-gain haptic guidance schemes and virtual practice. The results from a month-long training experiment indicate that the proposed progressive shared control scheme reduces guidance interference as compared to fixed-gain guidance schemes thus increasing training efficacy.