A simple nonlinear PD controller for integrating processes

作者：Dey Chanchal; Mudi Rajani K^*; Simhachalam Dharmana

来源：ISA Transactions, 2014, 53(1): 162-172.

DOI：10.1016/j.isatra.2013.09.011

• PID control
• Nonlinear PD control
• Integrating process

Many industrial processes are found to be integrating in nature, for which widely used Ziegler-Nichols tuned PID controllers usually fail to provide satisfactory performance due to excessive overshoot with large settling time. Although, IMC (Internal Model Control) based PID controllers are capable to reduce the overshoot, but little improvement is found in the load disturbance response. Here, we propose an auto-tuning proportional-derivative controller (APD) where a nonlinear gain updating factor alpha continuously adjusts the proportional and derivative gains to achieve an overall improved performance during set point change as well as load disturbance. The value of alpha is obtained by a simple relation based on the instantaneous values of normalized error (e(N)) and change of error (Delta e(N)) of the controlled variable. Performance of the proposed nonlinear PD controller (APD) is tested and compared with other PD and PID tuning rules for pure integrating plus delay (IPD) and first-order integrating plus delay (FOIPD) processes. Effectiveness of the proposed scheme is verified on a laboratory scale servo position control system.

• 出版日期2014-1