Adaptive Impedance Control with Compliant Body Balance for Hydraulically Driven Hexapod Robot

Abstract

This article described on the implementation of impedance control with the adaptive elements and compliant walking mechanism in hydraulically driven hexapod robot named COMET-IV. The main issue when applying impedance control in this robot is the body attitude stability during walking on the uneven terrain that contains of major soft surface. The impedance controller is derived for each leg from vertical motion changes. In addition self-tuning stiffness method is proposed as an adaptive element from the changes of the robot's body attitude vector (magnitude), to ensure the robot is self-adapted with the changes of stepped ground. On the other hand, compliant walking mechanism is designed for force-based walking trajectory and proposed impedance controller integration. The proposed controller and mechanism are verified by running the robot on the designed uneven terrain (extremely soft surface) in the laboratory using critical condition of side walking setting.