弹药协调器非线性连续时变反馈控制

Nonlinear continuous time-varying feedback control of an ammunition coordinator

摘要:

为解决某弹药协调器的精确快速定位控制问题,研究了一种基于隐式Lyapunov函数的连续时变反馈控制方法,该方法在控制律形式上类似PD控制,但其中的比例和微分系数取决于系统Lyapunov函数,是系统误差变量的可微函数. 首先,采用第2类Lagrange方法建立了系统的动力学模型,在此基础上,针对协调器系统存在的摩擦和小平衡机支反力矩非线性干扰问题,对这两项进行了精细建模,其中摩擦力矩项采用的是LuGre模型. 建模后,根据动力学模型具体结构设计实验,并通过实验数据采用遗传算法辨识了摩擦力矩和支反力矩模型中的关键参数. 为进一步缩短协调器的定位控制时间以提高其协调效率和性能,基于辨识后的模型,在控制中引入了摩擦力矩和支反力矩的前馈补偿项. 实验结果表明,所研究的控制方法对负载不确定性有较强的鲁棒性,在负载发生变化的情况下能够始终保证系统的定位时间和定位精度. 此外,对于摩擦和小平衡机支反力矩的非线性干扰补偿可以将协调定位时间缩短25.1%,由为补偿前的2.07 s缩短到1.55 s,同时保证了协调器的运动定位精度,验证了算法的有效性.

Abstract:

For the precise and fast position control of an ammunition coordinator, a continuous time-varying feedback control method based on implicit Lyapunov function was proposed. The method is PD-like in the form of control law, but its proportional and differential coefficients depend on the system Lyapunov function, which are differentiable functions of system error variables. First, the dynamic model of the system was established through the second Lagrange equation. Two main nonlinear disturbance terms of the ammunition coordinator system (i.e., friction torque and balance torque) were modeled in detail, where the friction term was modeled via LuGre model. Then, experiments were designed according to the structure of the dynamic model, and key parameters in the friction torque and balance torque terms were identified through genetic algorithm using experimental data. To further shorten the positioning time of ammunition coordinator and improve its coordination efficiency and performance, the model-based feedforward compensation of the friction torque and balance torque were introduced into the control strategy. Experimental results show that the proposed control method was robust to system payload uncertainty. With varying payload, the positioning time and accuracy of the system were guaranteed. In addition, the nonlinear disturbance compensation of the friction torque and balance torque shortened the positioning time by 25.1%, from 2.07 s to 1.55 s. Meanwhile, the positioning accuracy was guaranteed, which verified the effectiveness of the proposed method.