自抗扰技术在下肢康复训练器中的应用

Application of ADRC in lower limb rehabilitation training apparatus

为避免下肢弱肌力人群因缺乏运动而导致的血液循环不畅、肌肉萎缩甚至中风等严重后果,设计了一种新型卧式下肢被动康复训练器,当人体下肢无法自主运动时,训练器可以辅助下肢进行运动.因不同的训练目标和不同使用者都会引起负载变化,为适应训练器控制,提出了改进型线性自抗扰控制(LADRC)策略,并设计了速度自抗扰控制器.最后通过仿真和样机实验验证了LADRC策略具有较好的性能,能够满足训练器被动康复训练的需求.研究表明,采取预先估计系统扰动范围、对内环扰动补偿限幅和对外环使用输出反馈等措施,可以有效地克服因线性扩张状态观测器(LESO)估计误差而导致过补偿的不足,并保留了参数设计简单的优点,同时能使观测器补偿因子b 0的稳定范围扩大10倍以上.

To avoid poor blood circulation,muscle atrophy and even serious consequences such as a stroke,caused by lack of exercise,a new horizontal-type lower limb rehabilitation apparatus for passive training is designed for people with lower limb weakness.When people cannot move lower limbs actively,the apparatus will assist lower limbs in exercising.Since different training targets or different users will cause loads to change,an improved linear active disturbance rejection control(LADRC)strategy adapted to the apparatus is proposed,and the speed controller is designed.Finally,both simulation and prototype experiments were carried out,indicating that the improved LADRC strategy has better performance and it can meet the demand of passive training.According to the range of the system disturbance estimated in advance,the disturbance compensation in the inner loop is limited.Meanwhile,the output feedback is adopted in the outer loop.Therefore,the excessive compensation caused by the estimation error of the linear extended state observer(LESO)can be overcome effectively,the advantage of simple parameter design can be retained,and the stable range of observer compensation factor b 0 can be extended by more than 10 times.