为提高开放式伺服系统的动态性能,使其具有良好的适应能力,提出一种基于LuGre模型的自适应摩擦补偿方法。建立开放式伺服系统的动力学模型,并通过LuGre模型来描述系统的摩擦特性。考虑到摩擦模型的参数会随系统变化而发生改变,采用Backstepping方法设计自适应摩擦补偿控制器,并采用Lyapunov定理证明系统的全局渐进稳定性。通过可编程多轴控制器(Programmable multi-axis controller,PMAC)编写伺服算法实现该自适应摩擦补偿方案,并通过试验验证该方案的有效性。试验结果表明:与传统的速度加速前馈补偿相比,该自适应摩擦补偿方案在正弦运动作为输入信号时,其跟踪误差由±40μm降低到±7μm。采用该补偿方案能有效地抑制摩擦干扰对伺服系统的不利影响,为提高伺服系统的动态跟踪性能奠定基础。
In order to promote the dynamic performance and improve the adaptive ability of the open servo system,an adaptive friction compensation based on LuGre model is presented.The dynamic model of open servo system is established,and the friction characteristics are described based on LuGre model.Considering the parameters of friction model changed with the system,the controller of adaptive friction compensation is designed through backstepping method,and the global asymptotic stability of control system is proved by Lyapunov theorem.The adaptive friction compensation scheme is achieved by programmable multi-axis controller(PMAC),and the effectiveness of the scheme is verified by experiments.The experimental results show that comparing with the conventional feedforward compensation of velocity and acceleration,the adaptive friction compensation makes the tracing error of the sinusoidal motion decreases from ±40 μm to ±7 μm.Therefore,the proposed compensation scheme can effectively inhibit the disadvantageous influence of friction and lay the foundation for improvement of dynamic performance of servo system.