Research on Leg Impedance Control for Electronic Wheel-Legged Robot Based on Fractional Order

In order to reduce the impacts and improve robot's adaptability to complex terrain, position-based impedance control was applied to the compliance control for legged locomotion of the electronic wheel-legged robot and a new impedance controller with fractional order was proposed to improve the contact performance. As the bandwidth of the position closed-loop could affect the realization of the target impedance, an inverse position-loop compensator was introduced to improve the system impedance tracking performance. Simulation and experiment results show that the fractional-order impedance control can not only realize stable contact between the foot and the ground, but also achieve superior contact transition performance in comparison to the conventional second-order mass-damping-spring impedance controller.