Abstract: The spinal joint enhances the terrain adaptability of quadruped robots, but it also significantly increases control complexity and intensify energy consumption, thereby limiting their operational endurance. To address these challenges, this paper proposes an energy consumption optimization method based on hybrid force-position control and energy characteristic parameters, aiming to reduce the energy consumption of the spinal joint quadruped robot in trot gait. Firstly, based on the characteristics of the spinal joint, the kinematic model of the robot is established, and the Jacobian matrix is derived. A hybrid force-position control framework for spinal joint quadruped robot is designed. A Virtual Model Controller (VMC) for trot gait is developed to coordinate the motion of the stance and swing legs, with flexible control integrated into the spinal joint. Subsequently, the actuator energy consumption model is established, and the energy characteristics of the robot with different gait and spinal joint parameters are tested. A fitness function combining energy consumption metrics, stability indicators and heuristic reward terms is constructed, and the energy-saving strategy of the robot is designed using the improved Particle Swarm Optimization (PSO) algorithm. Finally, a prototype of the spinal joint quadruped robot is developed and tested across diverse terrains. Both the simulation and experimental results demonstrate that the method proposed in this paper effectively reduces the locomotion energy consumption of the spinal joint quadruped robot in trot gait.

Key words: Spinal joint quadruped robot')">Spinal joint quadruped robot, VMC, Hybrid force-position control, Energy consumption optimization, Energy characteristics