Performance improvement of bilateral control systems using model-based friction compensation and interpolation of position information

Recent years, real world haptic techniques have been developed. A bilateral control scheme is utilized for haptic devices, where force and/or position information of master slave system is transported each other. It is well-known that control performance of bilateral systems strongly depends on hardware restriction and computational power, however providing high performance hardware needs additional cost. In this research, a steer-by-wire(SBW) system is utilizing as one example of the bilateral control system with low resolution position sensors. For this system, in order to improve estimation capability, a state observer utilized for interpolation of position information is applied to the reaction force observer. Moreover in order to solve the problem that non-linear friction in ball guide of the slave system afl´ects the positioning performance of the system, model-based feed forward disturbance compensation is applied to compensate for non-linear friction. The effectiveness of the proposed method has been verified by experiments using a prototype of the SBW system.