Modern Control Systems Pr Introduction to Modular Servo

Modern Control Systems (Pr) Introduction to Modular Servo System Lab-4: Development of characteristics of D. C Motor Lab-5: Formation of Error Channel Lab-6: Experimental Determination of Transfer function Dr. Imtiaz Hussain Assistant Professor email: imtiaz. hussain@faculty. muet. edu. pk URL : http: //imtiazhussainkalwar. weebly. com/ 1

Outline • Introduction to MS 150 • Experiment#4 – Speed Voltage characteristics of D. C Motor • Experiment#5 – Formation of Error channel • Experiment#6 – Experimental Determination of Mathematical Model (System Identification)

Modular Servo System (MS 150) • The MS 150 Modular Servo System is a unique equipment designed to study theory and practice of automatic control systems. • Operation Amplifier Unit (OU 150 A) • Attenuator Unit (AU 150 B) • Pre-amplifier Unit (PA 150 C) • Servo Amplifier (SA 150 D) • Power Supply (PS 150 E) • Motor-Tacho Unit (MT 150 F) • Input potentiometer (IP 150 H) • Output Potentiometer (OP 150 K) • Load Unit (LU 150 L)

Modular Servo System (MS 150) • Power Supply (PS 150 E)

Modular Servo System (MS 150) • Servo Amplifier (SA 150 D)

Modular Servo System (MS 150) • Motor-Tacho Unit (MT 150 F)

Modular Servo System (MS 150) • Operation Amplifier Unit (OU 150 A)

Modular Servo System (MS 150) • Pre-amplifier Unit (PA 150 C)

Modular Servo System (MS 150) • Attenuator Unit (AU 150 B)

Modular Servo System (MS 150) • Input potentiometer (IP 150 H) • Output Potentiometer (OP 150 K)

Modular Servo System (MS 150) • Load Unit (LU 150 L)

Experiment#4 Development of characteristics of D. C Motor

Characteristics of D. C Motor • Motor Characteristics (Armature control Mode)

Characteristics of D. C Motor • Motor Characteristics (Field control Mode)

Characteristics of D. C Motor com +15 Experimental set up (Armature Control Mode)

Characteristics of D. C Motor • Connect the voltmeter across the tacho outputs and switch on the power. • Turn the slider on the potentiometer till there is a reading of 1 V on the voltmeter. • Count the turns of the geared 30: 1 low speed shaft in one minute. • Tabulate your result in following table. S. No Tachogenerator Volts (Vg) 1 1 2 2 3 3 4 4 5 5 6 7 7 10 Vin No. of rotations of low Speed Shaft (a) Speed in rev/min N=30×a

Characteristics of D. C Motor • Plot the graph of your results, as in following figure, of speed against Tachogenerator volts. The calibration factor should be about 2. 5 V to 3 V per 1000 rev/min. calibration factor =

Experiment#5 Error Channel

Error Channel r e - Controller Plant c

Error Channel Closed Loop Position Control System

Error Channel • In a closed loop position control system reference input and output are angular positions. e - Controller Plant

Position Control System (Block Diagram) I/P Potentiometer Summing amplifier Attenuator Pre-Amp O/P Potentiometer Servo. Amp D. C Motor

Calibration • Before connecting the two sliders into the operational amplifier inputs make certain that the slider resistance is same on both input and output potentiometers for all angular positions. • If not, then loosen the dial and make an adjustment.

Readings S. No Input potentiometer V 1 Output potentiometer V 2 V 1 - V 2 Vo(Measured)

Experiment#6 Experimental Determination of Transfer Function

Practical Determination of Transfer Function of 1 st Order Systems • Often it is not possible or practical to obtain a system's transfer function analytically. • Perhaps the system is closed, and the component parts are not easily identifiable. • The system's step response can lead to a representation even though the inner construction is not known. • With a step input, we can measure the time constant and the steady-state value, from which the transfer function can be calculated.

Practical Determination of Transfer Function of 1 st Order Systems • If we can identify T and K from laboratory testing we can obtain the transfer function of the system.

First Order System With Delays

Determination of Transfer Function of Armature Controlled D. C Motor • Armature Controlled D. C Motor (La=0) Ra u La ia B eb T J an t s n =co Vf t

Step Response of D. C Motor • Apply square wave of amplitude 10 volts and frequency 0. 1 Hz. Armature Controlled D. C Motor v 10 0 -10 5 10 15 t

Experimental Setup

To download this lecture visit http: //imtiazhussainkalwar. weebly. com/ END OF LAB-4 -5 -6