MECH 371 – Analysis and Design of Control Systems
Lab #6:
TIME RESPONSE OF BASIC CLOSED-LOOP SPEED CONTROL SYSTEM AND EFFECT OF
TORQUE LOAD
LAB SECTION: XM-X
Professor: Dr. Brandon Gordon
GROUP MEMBERS:
Jordan Cos
...
MECH 371 – Analysis and Design of Control Systems
Lab #6:
TIME RESPONSE OF BASIC CLOSED-LOOP SPEED CONTROL SYSTEM AND EFFECT OF
TORQUE LOAD
LAB SECTION: XM-X
Professor: Dr. Brandon Gordon
GROUP MEMBERS:
Jordan Costenaro ID#: 27488920
Maria Tzougarakis ID#: 40001245
Patrick Cumming ID#: 40000732
Date of Experiment: Friday, April 6, 2018
Date of Report Submission: Friday, April 13, 2018
11. Objective:
The objective of this experiment is to analyze and study the time response of a
closed-loop DC motor speed control system and to analyze the performance of load effect of the
system response.
2. Introduction:
The block diagram of the closed loop speed control is show below. The feedback signal is
the output velocity signal Vo (or vt), which is seen from the tachometer, which is then compared
with a reference voltage Vi where error is determined by Ve=Vi-Vo. The angular velocity of the
motor which is the tachogenerator is coupled directly to the end of the motor. It produces a DC
voltage output Vo = Vt = Ktωm
Figure 1: Basic Closed-Loop Speed Control System [1]
OA 150 A (set in External Mode) will be used for signal summation and as an amplifier
for adjusting proportional gain. As shown in the figure below where α is the fraction of voltage
across the potentiometer, the the overall gain will be − α1 if R1 = R2.
Figure 2: OA150 A for Proportional Gain Amplifier [2]
2Figure 3: DC Motor Speed Control with PID Compensation [2]
Figure 4: DC Motor Proportional Speed Control [3]
3. Procedure:
Experiment #1:
Without power on, set up the circuit as shown in figure 4, OA150A must be set to
external mode, with the function generator connected to terminal 2 of OA150A. Function
generator settings: square wave, Hi: 4V, Lo: 0V, Freq. 0.3Hz. Scope CH1 to terminal 2 of
OA150A and CH2 to terminal 3. Set scope to roll mode and observe various Kp settings which is
the top pot adjustment knob on the attenuator. Connect PA150C output 3 and 4 to SA150D to
input 1 and 2. If the system is unstable, switch polarities of GB150X. Capture results with load at
0 and at 10 with Kp set to 1 and 10 for both loads.
Experiment #2:
Now set up the circuit as shown in the block diagram in figure 3, it is similar to the
position control setup. Please note that the feedback is from tacho-generator GB150X, function
generator inputs are the same as experiment 1. Perform the following tests: Kp = 10, no Ti, no
load; Kp = 10, Ti = 0.1, no load; Kp = 1, no Ti, no load; Kp = 1, Ti = 0.1, no load; Kp = 10, no
3Ti, load at 10; Kp = 10, Ti = 0.1, load at 10; Kp = 1, no Ti, load at 10; Kp = 1, Ti = 0.1, load at
10.
4. Results:
Experiment #1:
Figure 5: Response of a Closed-Loop Proportional Speed Control System
Kp = 1, Load Position 0
Figure 6: Response of a Closed-Loop Proportional Speed Control System
Kp = 1, Load Position 10
4Figure 7: Response of a Closed-Loop Proportional Speed Control System
Kp = 10, Load Position 0
Figure 8: Response of a Closed-Loop Proportional Speed Control System
Kp = 10, Load Position 10
Experiment #2:
Part 1:
Figure 9: Response of DC Motor Speed Control with P Compensation
Kp = 10, No Ti, Load Position 0
5Figure 10: Response of DC Motor Speed Control with P Compensation
Kp = 1, No Ti, Load Position 0
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