Low Impact Force and Energy Consumption Motion Planning for Hexapod Robot with Passive Compliant Ankles

Motion planning plays an important role in the performance optimization of legged robots. This paper presents a method to minimize the impact force and energy consumption effectively by providing an integrated strategy of motion planning subject to velocity and acceleration constraints. The parameters defined for the motion planning are computed to generate the foot trajectory. A foot–terrain interaction model and an energy-consumption model are formulated to evaluate the contact force and power consumption for statically stable gaits. The proposed method has been implemented on a hexapod robot. The acceleration of foot landing is reduced, and constant velocity control of the trunk body with passive compliant ankles is achieved for reducing the impact force and energy consumption. Extensive experiments have been carried out, and the experimental results have demonstrated the effectiveness of the proposed method in comparison with a conventional method.