Nonlinear continuous time-varying feedback control of an ammunition coordinator

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.