基于PAC的在线模糊自适应PID控制器设计

Design of online ruzzy self-adaptive PID controller based on PAC

PID控制适合用于已知精确数学模型的被控对象,具有稳态误差小等特点.模糊控制不需要被控对象的数学模型,响应速度快,但是有静差.将这两种控制技术相结合,设计一种模糊自适应PID控制器,具有响应速度快、稳态误差小的特点.采用上位机和PAC结合,上位机中的iFIX组态软件利用OPC技术和MATLAB软件中的模糊控制器通讯,把实时值和设定值送给模糊控制器,同时把模糊控制器的输出(比例系数、积分系数和微分系数)送回PAC,在PAC中根据PID算法计算控制量,由PAC控制被控对象,实现在线模糊自适应PID控制.对水箱液位进行控制的结果表明,采用在线模糊自适应PID控制器后,控制系统的响应速度加快,无超调,具有较好的稳定性和鲁棒性.

PID controller suits for controlled objects with an accuracy model, and has small static error. Fuzzy controller does not need an accuracy model and responses fast, but it has static error. Combining the above two technologies, a fuzzy self-adaptive controller is designed. It quickly responds with the change of inputs and has small static error. The proposed fuzzy self-adaptive controller is implemented in PAC with an upper monitor, iF- IX in an upper monitor communicates with a fuzzy controller in Matlab by using OPC technology. The process value and process set point are sent to the fuzzy controller. At the same time, the outputs of a fuzzy controller （ proportional gain, integral gain, derivative gain） are sent back to PAC. Control variable output is calculated in PAC. PAC controls the object online with a fuzzy self-adaptive controller. The testing results for tank level show that the proposed controller response fast and has no overshoot. It also has good stability and robust.