Robust Variable Phase Shaper for vibration suppression of start-stop motion of a spherical rolling robot

This paper presents a technique to design and implement a robust command shaper to reduce the residual vibration of a spherical rolling robot. The system of interest is VIRGO, a novel miniaturized spherical rolling robot designed for surveillance and reconnaissance. Given the high order nonlinearity of VIRGO, a second order linear approximation is first achieved through analysis of the system's forced response. Subsequently, Zero Vibration (ZV), Zero Vibration with Derivative (ZVD), and Robust Variable Phase (RVP) shapers, including the Extra-Insensitive (EI) Shaper, were designed and implemented. The performance of the robot's unshaped and shaped responses were evaluated in terms of their settling time and maximum overshoot. Experimental results show that the proposed Robust Command Shaping techniques are able to prevent flipping over while reducing residual vibration across varying changes to the system parameters.