基于输入频率模型的步进电机失步非线性补偿

摘要

步进电机受输入脉冲频率的影响,开环控制时会出现失步和过冲等非线性特征,影响控制系统的精度.通过研究不同输入频率下步进电机的输出特性,利用系统辨识的方法,建立步进电机非线性依赖输入频率的数学模型.基于所得步进电机的脉冲-频率辨识模型,利用逆补偿方法,对非线性的影响进行补偿.实验结果表明,对于步进电机驱动的传动装置,该方案可有效消除因失步或过冲引起的非线性误差,提高了定位精度,该方法简单可靠,可为类似传动系统的非线性补偿提供参考.%The behavior of the stepper motor is affected by the frequency of the input pulse.The nonlinear characteristics such as the step-out and overshoot would degrade the positioning performance of stepper motors when the open-loop control strategy was used.To compensate the nonlinearities,an input-rate dependent model was derived based on the input-output data of the stepper motor when fed with input impulses of different frequencies.The parameters of the model were identified by the least squares algorithm.Mterwards,the nonlinear effects are compensated using the inverse method based on the obtained model.The experimental results show that the proposed approach can effectively eliminate the influence caused by the step-out or overshoot of the stepper motor and improved the positioning accuracy.Meanwhile,it is simple and reliable in the practical applications.Therefore,the proposed scheme is of great reference for the nonlinear compensation of similar transmission system.