摘要
比例微积分(PID)算法是根据系统检测或操作偏差,利用比例、积分、微分运算获得所需调节量以对系统进行反馈控制,因其操作极为方便而广泛用于工程实践。其核心技术是精密确定PID的比例、积分、微分系数。在功能性电刺激应用中,由于PID的稳定性好、工作可靠,对肌肉的复杂性和时变性不敏感,所以得到了广泛的应用。由于功能性电刺激(FES)对于系统反馈控制的鲁棒性要求更为严格,故对于PID实施控制提出更高的要求。利用遗传算法(GA)进行PID控制系数的整定,并尝试用于下肢膝关节角度运动的FES控制,使之能按预定轨迹完成康复动作。对6名受试者进行刺激实验的结果表明:与传统的Ziegler-Nichols整定PID算法相比,基于遗传算法整定的PID算法控制下FES系统偏差可以维持在相对更低范围内以使膝关节运动轨迹与预设目标更好地吻合,从而保证更为稳定的康复训练效果。
PID （proportional-integral-differential） is a common control loop feedback mechanism （controller） widely used in industrial control systems.It attempts to correct the error between a measured process variable and a desired setpoint by the proportional,the integral and derivative operation and how to confirm the proportional,integral and derivative values is the most important in practical applications of PID.Functional Electrical Stimulation,which is a technique that uses electrical currents to activate nerves innervating extremities affected by paralysis,has been used in the area of neural engineering gradually.An exigent PID control is expected in Functional Electrical Stimulation as its especial stability requirement.This paper adopts Genetic Algorithm based PID arithmetic whose parameters were modulated to control the knee angle by FES to move along the trajectory set in advance.Experiment result shows that the FES system with GA-based PID arithmetic can get a relative lower error when track the trajectory of knee angle which is designed in advance compare with the system adjusted by Ziegler-Nichols tuning PID algorithm.
出处
《中国医学装备》
2011年第10期70-74,共5页
China Medical Equipment
