PID feedback controller

Proportional plus integral plus derivative (PID) feedback controllers, 20 692-693. See also Digital PID controllers Proportioning, 26 226 batch, 26 249-251... 

There are two very popular ways to control systems with inverse response the first uses a PID feedback controller with Ziegler-Nichols tuning and the second uses an inverse response compensator. 

Consequently, the fabrication of a DE actuator (DEA) that can produce linear motion, called a multi-stacked actuator is presented in this chapter [Chuc et al. (2011)]. It is made of the aforementioned synthetic elastomer, which is a kind of DE as introduced in Chapter 6. The proposed actuator does not need any pre-strain to amplify the displacement and force. It just includes multiple, synthetic elastomer layers, where the electrode layers are connected in parallel. To improve the performance of the proposed actuator, the shape of the actuator is optimized to yield large deformations. Moreover, a high-voltage switching circuit is developed to drive the proposed actuator. In this circuit, the pulse-width-modulated proportional-integral-derivative (PWM-PID) feedback controller is incorporated. The performance of this controller is compared with that of a continuous PID controller via experiments. 

This chapter presented a flow diagram of a PID feedback control loop with the process streams and instrument lines labeled. The proportional, integral, and derivative actions of the controller were defined mathematically and described for the example in the diagram. 

Fig.5.45a-d. Schematic diagram of PID feedback control (a) noninverting proportional amplifier (b) integrator (c) differentiating amplifier (d) complete PID circuit that combines the functions (a-c)... 

In certain special circumstances - emergencies, startups, and shutdowns -model-predictive control cannot be used. It is more realistic to say that well-tuned, well-maintained model-predictive control application can emulate the plant s best operator - every minute of every day. Figure 4 compares the temperature response to a soot-blowing disturbance under three types of control. The solid line shows the open-loop (manual) response. The heavily dotted line shows better response with a PID (feedback) controller. The lightly dotted line shows superb response with model-predictive control. 

---