Leg Parameters Optimization of Wheel-Legged Vehicle Based on Trot Gait

The leg parameters of the wheel-legged vehicle have a certain influence on the movement in the legged mode and the wheel-legged compound mode of the vehicle. This paper selects the trot gait motion, and optimizes the leg length and mass of the vehicle according to the data under this working condition. We model the kinematics and dynamics, providing model consistency constraints for the optimization problem. Then the commonly used trot gait trajectory is planned, input into the built multibody dynamics model, and the center of mass and wheel information of this working condition are obtained, and these data will be used for optimization problems. We set two goals of minimum torque and minimum energy consumption, determined some necessary constraints, established an optimization problem, and solved it by genetic algorithm. The optimization result is a 16.9% increase in thigh length and a 15.1% decrease in calf length. We resubstitute this result into the multibody dynamics model for simulation and obtain comparative data. Among them, the knee joint torque was reduced by 13.3%, and the total energy consumption of a single leg was reduced by 6.3%, indicating the effectiveness of the optimization.