基于Bouc-Wen修正模型的柔性关节驱动器迟滞建模

为了研究柔性关节驱动器输出力的迟滞影响，提高力控制精度，构建了柔性关节驱动力的迟滞实验台,提出柔性关节驱动器输出力的Bouc-Wen修正方法对力迟滞进行精确建模，并通过龙格-库塔-费尔贝格算法对BoucWen修正模型进行参数辨识.在Bouc-Wen模型的基础上，引入具有方向性的修正项，克服柔性关节驱动器的输出力-转角迟滞的非对称性.利用关节驱动器在60、80、100、120 kPa充气压力下的力迟滞实验数据，建立Bouc-Wen修正模型.在70、90、110 kPa充气压力下，将Bouc-Wen修正模型所预测的柔性关节力迟滞曲线与经典Bouc-Wen模型以及实验曲线进行对比.结果表明所提出的力迟滞Bouc-Wen修正模型，在各充气压力下的最大相对误差仅为7.75%，平均偏差小于0.45 N，模型拟合优度大于0.99.说明所提出的Bouc-Wen修正模型能够对柔性关节驱动器的力迟滞进行准确建模，为力闭环控制提供基础，也为其他超弹性材料柔性驱动器的迟滞建模提供参考方法.

Modified Bouc-Wen based hysteresis modeling of flexible joint actuator

A hysteresis test bench for flexible joint driving force was constructed, in order to study the force hysteresis characteristic of the flexible joint actuator and improve the force control accuracy. The modified Bouc-Wen method was proposed to accurately model the force hysteresis of the joint actuator, and the parameters of the modified Bouc-Wen model were identified by the Runge-Kutta-Fehlberg method. On the basis of the conventional Bouc-Wen model, a directional correction term was introduced to overcome the asymmetry of the output force-angle hysteresis of the flexible joint actuator. The modified Bouc-Wen model was established, using the experimental data of force hysteresis of joint actuator at 60, 80, 100 and 120 kPa inflation pressure. The hysteresis curve predicted by the proposed Bouc-Wen model was compared with that of the conventional Bouc-Wen and the experimental curve at 70, 90 and 110 kPa inflation pressure. Experimental results show that the maximum relative error of the proposed Bouc-Wen based force hysteresis model for the flexible joint actuator under each inflation pressure was only 7.75%, the average deviation remained within 0.45 N, and the fitting goodness of the model was more than 0.99. Results show that the proposed modified Bouc-Wen model can accurately describe the force hysteresis of the flexible joint actuator, which lays a foundation for the force closed-loop control and also provides a promising method for the hysteresis modeling of other hyperelastic flexible actuators.