随机不确定扰动诱发的机器人动力学行为及其优化

研究随机不确定扰动诱发的平面三杆双足机器人动力学行为,并对其进行优化。在实现理想情形下平面三杆双足机器人稳定行走的基础上,建立了随机不确定扰动下双足机器人的运动学模型、混杂动力学模型,研究了具有HZD反馈控制的机器人在随机不确定扰动下的动力学行为;针对随机不确定扰动,提出了一种BPNN-HZD反馈控制方法,采用该方法对平面三杆双足机器人进行控制,优化其动力学行为。仿真实验结果表明:当平面三杆双足机器人不能以足够大的力度补偿随机不确定扰动影响时,机器人会逐渐出现发散的动力学行为;BPNN-HZD反馈控制方法能够显著减弱随机不确定扰动对机器人动力学行为的影响,从而有效避免机器人的发散动力学行为。

Dynamic Behavior and Its Optimization of Robot under Randomly Uncertain Disturbance

The dynamic behavior and its optimization of a planar 3-link biped robot under randomly uncertain disturbance were investigated. Based on the biped kinematic model and hybrid dynamic model under ideal situation, the control objective function and HZD (Hybrid zero dynamics) feedback control were firstly established, from which the biped state parameters were optimized with the energy consumption function, and the robotic stable walking under the ideal situation was achieved. Secondly, the biped kinematic model and hybrid dynamic model under the randomly uncertain disturbance were established, from which the robotic dynamic behavior controlled by the HZD feedback control method was investigated under the randomly uncertain disturbance. Finally, taking the randomly uncertain disturbance into account, the disturbance compensator integrated into the HZD feedback control was constructed based on a back propagation neural network, and a novel BPNN-HZD (Back propagation neural network-hybrid zero dynamics) feedback control method was proposed to optimize the biped dynamic behavior. The dynamic simulation results and the stick figures showed that the planar 3-link biped robot would gradually appear divergent dynamic behavior if the randomly uncertain disturbance could not be well compensated, while the BPNN-HZD feedback control can effectively weaken the randomly uncertain disturbance effect on the dynamical response of robot, and the biped divergent dynamic behavior would be avoided.