Research and Analysis of Comprehensive Optimization Method for Energy Consumption and Trajectory Error of the Leg Structure Based on Virtual Model Control

Abstract

The virtual model control (VMC) method realizes the direct mapping from the overall control target to the joint-level control commands by establishing the virtual force corresponding to the motion control target. This control method that does not directly involve the dynamic model is easy to calculate and implement, while the values of the stiffness and damping parameters in the virtual force equation have a direct impact on the control effect. Therefore, realizing the reasonable setting of the above parameters is an important problem that needs to be solved in the application of the VMC method. This paper takes the swing motion of the leg mechanism of a quadruped robot as an example to study. In the VMC framework, an optimization method based on energy consumption and motion trajectory errors as evaluation indicators is proposed. The genetic algorithm was used to implement specific optimization calculations in detail, and the comprehensive optimization of the stiffness coefficient and damping coefficient in the virtual force model was realized. Moreover, the optimization results obtained by using multiple fitness functions are compared and analyzed. Finally, cosimulation and basic physical experiments are performed to verify the effectiveness of the method proposed in this paper.