A Discrete-time Model Reference Adaptive Control for Velocity Loop in a Gyro-stabilized Platform

Based on the nonlinear velocity loop model for a four-gimbal,two-axis,gyro-stabilized platform and the feed-forward compensation of nonlinear friction torque,a model reference adaptive control is introduced for a gyro-stabilized platform system. Based on the control system structure and the relationship between the input and output as well as the generalized output error,a discrete model reference adaptive control system is established,and an adaptive controller with adjustable functionality is derived. To solve the problem of large or infinite adjustable functions when the denominator is zero or near-zero,the method is improved by using the last time value of the function when the denominator is less than the preset threshold. To demonstrate the superiority of the proposed controller,experiments are conducted to compare the performance of the model reference adaptive control system and the PI control system. The experimental results are analyzed to ensure that the nonlinear friction torque is sufficiently compensated. A new high-precision control strategy is proposed to further improve the control performance of the gyro-stabilized platform.