Faculty: FAKULTI KEJURUTERAAN ELEKTRIK Subject : MAKMAL

KEJURUTERAAN ELEKTRIK

Subject Code : SEE 3732

Review Release Date Last Amendment Procedure Number

: 1 : 2003 : 2003 : PK-UTM-FKE-(0)-10

SEE 3732

FAKULTI KEJURUTERAAN ELEKTRIK UNIVERSITI TEKNOLOGI MALAYSIA

KAMPUS SKUDAI JOHOR

CONTROL 1 LABORATORY

ANGULAR SPEED CONTROL

Experiment 1: Angular Speed Control Equipment Required CE110 Servo Trainer CE120 Controller Oscilloscope Part 1: Motor Calibration Characteristic Objective:

The objective of this experiment is to calibrate the circuit of the Servo Trainer, namely the input actuator (the motor circuit).

Procedure:

1. Connect the equipment as shown in figure 1

Figure 1

2. Set the initial setting for the servo trainer (CE110) and the controller

(CE120). CE110 : Disengaged clutch (i.e. disconnect position shaft) CE120 : Set potentiometer in the center position (the reading is 0V)

3. Slowly increase the potentiometer voltage (turning the potentiometer control clockwise) until the motor just starts to turn.

4. This is the size of the positive dead-zone for the motor drive amplifier, enter it into the second row of the Table 1 provided. .

5. Increase the potentiometer to 1V, record the corresponding motor speed from the speed display on the CE110 front panel.

6. Enter your results in Table 1. Increase the coarse potentiometer voltage in 1V steps to 10V and record the corresponding speed in Table 1.

7. Repeat the procedure with negative voltages. 8. Repeat the above procedure with the clutch engaged, and complete Table 2. 9. Avoid running the Servo Trainer at high speed for prolonged periods with

the clutch engaged, as this may cause excessive wear of the gearbox.

Motor Drive Voltage (V) (Positive)

Motor Speed (rpm)

Motor Drive Voltage(V) (Negative)

Motor Speed (rpm)

0 0 0 0 Dead-Zone Size = 0 Dead Zone Size = 0

1 -1 2 -2 3 -3 4 -4 5 -5 6 -6 7 -7 8 -8 9 -9 10 -10

Table 1: Motor Drive Calibration (Clutch Disengaged)

Motor Drive Voltage (V) (Positive)

Motor Speed (rpm)

Motor Drive Voltage(V) (Negative)

Motor Speed (rpm)

0 0 0 0 Dead-Zone Size = 0 Dead Zone Size = 0

2 -2 3 -3 4 -4 5 -5 6 -6 7 -7 8 -8 9 -9 10 -10

Table 2: Motor Drive Calibration (Clutch Engaged)

Discussion/Conclusion

i. Why the different polarities of input voltage give different directions of motor movement.

ii. Plot the results from Table 1 and Table 2. iii From the graph, describe the relationship between input motor drive

voltage and motor speed reading. iv. Explain, why motor drive calibration with and without clutch engaged

give different result. Part 2: Speed Sensor Calibration Objective:

The objective of this experiment is to calibrate the circuit of the Servo Trainer, namely the output sensor (the speed sensors).

Procedure: 1. Connect the equipment as shown in Figure 3

Figure 3

2. Initial Settings: CE110, Clutch disengaged. CE120, Potentiometer in the

center position (the reading is 0V). 3. Slowly increase the potentiometer voltage until the speed sensor reads 1V. 4. Enter the corresponding speed reading in Table 3.

5. Repeat the process in steps of 1V for positive and negative speed sensor readings in the range -9V to +9V.

Motor Speed

(rpm) (Positive)

Speed Sensor Output (V)

Motor Speed (rpm)

(Negative)

Speed Sensor Output (V)

1 -1 2 -2 3 -3 4 -4 5 -5 6 -6 7 -7 8 -8 9 -9

Table 3: Speed Sensor Calibration

Discussion/Conclusion

i. Explain the concept of angular speed measurement ii. Plot your results using the data from table 3

iii. Calculate the speed sensor constant (i.e. V

rpm∆∆ )

Part 3: Measurement of Gain and Time Constant Objective:

The objective of this experiment is to determine the gain, G1 and time constant, T of the servo-motor transfer function with differing load (clutch engaged and disengaged) where the servo motor transfer function is given by

vyω =

11

+TsG

and yω = the speed sensor output voltage v = the motor drive input voltage

Procedure: 1. Connect the equipment as shown in Figure 4

Figure 4

2. Set the initial setting for CE110 and CE120

CE110 : Disengaged clutch CE120 :

• Let the level for the function generator @ zero position. • Read the voltage using voltmeter • Adjust the OFFSET until the voltage reading above is 0V • Don’t change the OFFSET position for the rest of the experiment.

3. Set the function generator with • Square wave with frequency of 0.05Hz (frequency setting Hz 0.01 and

X5) • LEVEL at 2.5

4. Set the potentiometer output at 2.5V. 5. Using an oscilloscope, observe that the square wave signal changes from 0V to 5V.

6. The output of the speed sensor will therefore be a series of step responses. 7. Record/draw the step response from oscilloscope. Find the time constant Tclutch

disengaged 8. From the step responses calculate the time constant T of the servo-motor transfer

function. Gl is the ratio of speed sensor output voltage and motor drive input voltage

9. Repeat the above procedure for the clutch engaged and find the time constant Tclutch

engaged Discussion/Conclusions:

i. Comment on the shape of the motor drive voltage to speed sensor output voltage characteristic. ii. Discuss why the time constants for the clutch engaged and disengaged are different.

Part4: Proportional Control of Servo Trainer Speed Objective:

The objective of this experiment is to implement a proportional controller of the Servo Trainer speed and investigate the steady state errors. In this part of the experiment we seek to verify that the steady state error, ess for various reference signal, yr and various Controller Gains is given by:-

ess = 11 Gk

y

p

r

+ Equation 1

Procedure: 1. Connect the equipment as shown in Figure 5; this has the corresponding block

diagram shown in Figure 6. 2. Set the initial setting for CE110 and CE120. CE110 : Disengaged clutch CE120 :

• Turn potentiometer fully anti-clockwise • Set the propotional gain, kp to 10 and switch in • Switch out the Derivative and Integral block

(You can also just use the P block of CE120)

Figure 5

Figure 6

3. Increase the reference speed, as given by the potentiometer, in steps of 1V from 2V to 10V and record the corresponding errors signals in Table 4.

4. Use Equation 1, the value of kp (10) and G1(use G1=l) to calculate the theoretical values of ess for the various values of yr and enter your results in Table 4 in the column provided.

Potentiometer Setting (Reference Speed yr)

Measured Steady State Error signal

(V)

Theoretical Steady State Error Signal

(V) 2 3 4 5 6 7 8 9 10

Table 4: Steady State Error for Various Reference Speeds

5. Set the potentiometer to give a reference speed signal, yr, of 5V. 6. Vary the controller gain kp from 1 to 10 in steps of 1 and record the

corresponding error signal readings in Table 5 . 7. Use Equation 1 to calculate the theoretical values of the error for each kp value

and enter the results in Table 5

Potentiometer Controller Gain kp

Measured Steady State Error signal

(V)

Theoretical Steady State Error Signal

(V) 1 2 3 4 5 6 7 8 9 10

Table 5: Steady Sate for Various Controller Gains

Discussion/Conclusions:

i. Discuss the steady state error based on various yr and various kp