Balancing on visco-elastic surfaces is a challenging task for legged robots, requiring effective reactive balance control strategies to maintain stability. In this paper, we present a comparative study of three reactive control approaches: proportional-derivative (PD) control, proportional-integral-derivative (PID) control, and sliding mode control, for legged robots under visco-elastic contacts. A simulation framework was developed to test the performance of the three control strategies on a six-legged robot model, subject to visco-elastic contacts of varying stiffness and damping coefficients. The results show that all three control strategies were effective in stabilizing the robot, but the PID control strategy performed better in terms of reducing the settling time and overshoot. PD and sliding mode control strategies were more robust to changes in contact conditions and exhibited better performance in some cases. The findings provide insights into the design and implementation of reactive balance control strategies for legged robots under visco-elastic contacts.

Reactive balance control,, legged robots,, visco-elastic contacts,

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