Leg Joint Trajectory Planning of a Cat-Inspired Falling Robot Driven by Pneumatic Muscles with Optimal Energy Consumption

In this paper, the leg joint trajectory planning with optimal energy consumption for a cat-inspired falling robot driven by pneumatic muscles (CIFRDPM) during its diagonal trotting gait is proposed. Firstly, the kinematics and energy consumption model of the leg joints of CIFRDPM are analyzed. Subsequently, a MATLAB/Adams co-simulation model for the leg motion of the robot is established, utilizing the composite pendulum line as a reference trajectory at its foot-end. Then, an optimized leg trajectory generation method combining a three-point Fourier series and cubic spline interpolation is developed, with parameters specifically tuned to minimize energy consumption of the leg joints during motion. The simulation results demonstrate that the CIFRDPM using Fourier optimized trajectory and the Fourier plus cubic spline interpolation optimized trajectory respectively achieve an 18.12 % and 19.63 % reduction of energy consumption during its diagonal trotting motion, compared to that using reference trajectory of the composite pendulum at the foot-end only.