Multidimensional modeling of physiological tremor for active compensation in handheld surgical robotics

Precision, robustness, dexterity, and intelligence are the design indices for current generation surgical robotics. To augment the required precision and dexterity into normal microsurgical work-flow, handheld robotic instruments are developed to compensate physiological tremor in real time. The hardware (sensors and actuators) and software (causal linear filters) employed for tremor identification and filtering introduces time-varying unknown phase delay that adversely affects the device performance. The current techniques that focus on three-dimensions (3-D) tip position control involves modeling and canceling the tremor in three axes (x-, y-, and z -axes) separately. Our analysis with the tremor recorded from surgeons and novice subjects shows that there exists significant correlation in tremor across the dimensions. Based on this, a new multidimensional modeling approach based on extreme learning machines is proposed in this paper to correct the phase delay and to accurately model 3-D tremor simultaneously. Proposed method is evaluated through both simulations and experiments. Comparison with the state-of-the art techniques highlight the suitability and better performance of the proposed approach for tremor compensation in handheld surgical robotics.