仿人柔性关节耦合建模及变负载振动抑制

Coupling Modeling of Humanoid Flexible Joint and Vibration Suppression at Variable Load

针对仿人柔性关节负载突变引起的关节振动问题,提出一种基于状态观测器的转矩补偿控制方法.通过控制电动机输出与扰动力矩等值的转矩增量,使关节力矩快速平衡变化后的负载力矩,缩短弹性元件被动适应负载变化的振荡过程.设计了估计负载扰动转矩和电动机转速的状态观测器,并利用Lyapunov函数证明其收敛性;建立基于比例积分-积分比例(PI-IP)转速调节器的驱动系统控制结构,并将观测器的输出前馈输入到转速调节器中,提高系统抗干扰能力.仿真结果表明,与比例积分微分(PID)控制和关节力反馈比例微分(PD)控制相比,所提方法能够在负载变化后的0.6 s内使电动机转速恢复稳定,并在1 s内实现关节振动抑制,关节转速调节时间分别缩短了约1.8 s和0.9 s,有效提升系统动态调节能力.最后,通过在一体化柔性关节测试平台上的实验,验证了所提方法的有效性.

Aimed at the joint vibration problem caused by the load change of humanoid flexible joint,a torque compensation control method based on state observer is proposed.By controlling the motor to output a torque increment equivalent to the disturbance torque,the joint torque can quickly balance the load torque and shorten the oscillation process of the elastic element passively adapting to the load change.A state observer for estimating load disturbance torque and motor speed is designed,whose convergence is proved by the Lyapunov function.The control structure of the drive system based on the proportional integral-intergral proportional(PI-IP)speed regulator is established,and the observer output feedforward link is added to the speed regulator to improve the anti-interference ability of the system.The simulation results show that compared with proportional integral differential(PID)control and joint force feedback proportional differential(PD)control,the proposed method can restore the motor speed to stability within 0.6 s after load change and realize joint vibration suppression within 1 s.Besides,the joint speed adjustment time is shortened by about 1.8 s and 0.9 s respectively,which effectively improves the dynamic adjustment ability of the system.Finally,the effectiveness of the proposed method was verified by experiments on an integrated flexible joint testing platform.