A PID controller is to be used to control the position of a

A PID controller is to be used to control the position of a manipulator arm on an automobile assembly line. Draw a block diagram of this system, complete with a PID feedback controller supplied with voltage proportional to position from an optical encoder. With the integral and derivative gains set to zero, the position oscillates around the setpoint when the proportional gain is set too high. It takes 0.45 seconds for each cycle of the oscillation. Use the Modified Ultimate Cycle Method to propose PID controller settings (P, I, D) if there is a steady-state error present and it is desirable to respond to error rate.

Solution

PID CONTROLLER

PD controller improves transient response and PI controller improves steady state response. PID controller is a combination of both the controllers which is used to improve overall time response of the system(steady state response + transient response)

Design of PID controller is complicated in practice

Inorder to understand PID controller we need sufficient knowledge about PI and PD controller and their performance charectoristics

CHARECTORISTICS OF PD CONTROLLER

G_C(S)=K_P +K_D*S

CHARECTORISTICS OFF PI CONTROLLER

G_C(S)=K_P+K_I/S=K_P[1+S/T_I]

where T_I=K_P/K_I= Reset time

RESET TIME : Time taken to reset the error after initiating the controller is reset time.

CHARECTORISTICS OFPID CONTROLLER

G_C(S)=K_P +K_I/S +K_P*S