labsheet servo motor system b

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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DEPARTMENT OF ENGINEERING MECHANICS

CONTROL LABORATORY

LAPORAN MAKMAL/LABORATORY REPORT

Kod M/Pelajaran/ Subject Code

ENGINEERING LABORATORY VI BDA 37101

Kod & Tajuk Ujikaji/ Code & Title of Experiment

Kod Kursus/ Course Code Seksyen /Section

Kumpulan/Group No. K.P / I.C No.

Nama Pelajar/Name of Student No. Matrik

Lecturer/Instructor/Tutor’s Name

1. 2.

Nama Ahli Kumpulan/ Group Members

No. Matrik Penilaian / Assesment

1. Teori / Theory 10 %

2. Keputusan /

Results 15 %

3. Pemerhatian /Observation 20 %

4. Pengiraan / Calculation 10 %

5. Perbincangan / Discussions 25 %

Tarikh Ujikaji / Date of Experiment Kesimpulan /

Conclusion 15 %

Tarikh Hantar / Date of Submission Rujukan /

References 5 %

JUMLAH / TOTAL 100%

COP DITERIMA/APPROVED STAMP

ULASAN PEMERIKSA/COMMENTS

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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COURSE INFORMATION

COURSE TITLE: ENGINEERING LABORATORY VI (BDA 37101) TOPIC 2: RESPONE CALCULATING & MEASUREMENT (SERVO MOTOR SYSTEM)

1. INTRODUCTION Servo Trainer as shown below comprises of a motor driven rotating shaft upon which is mounted having an inertial load flywheel, tachometer to measure shaft speed, electrically driven motor that provides power to rotate the shaft, electrically operated clutch to enable the motor driven shaft to be connected to a secondary shaft i.e position output shaft which connects to a 30:1 ratio reduction gearbox and output shaft position sensor.

2. OBJECTIVE The objective of this experiment is to determine the gain G1 and time constant T of the servo motor transfer function with differing inertial loads. 3. LEARNING OUTCOMES At the end of this experiment, students should be able to understand the operating principles of the Servo-motor control and its applications in industry.

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4. THEORY 4.1 SERVO SYSTEM MODELING: SPEED CONTROL SYSTEM Consider the servo control system with the clutch disengaged. In this configuration the system is a speed control process. The system model is determined by relating the torque supplied by the motor ( m ) to that required to drive the load generator, the flywheel and frictional losses. This can be expressed as; m Load Torque +Frictional Torque + Inertial torque The load torque can be considered as a torque which is proportional to the load control voltage while the frictional torque can be considered as a torque which is proportional to the shaft speed . The inertial torque is determined by the

flywheel inertia and the shaft accelerationdtd . Thus

dtdIvkbm

11 ………………………………(1)

Where b = Friction coefficient of rotating components 1k = Gain constant of load / generator I = Inertia of flywheel The motor electrical circuit is governed by the equation

bemfvdtdiLRitv …………………………..(2)

Where tv motor input voltage R motor armature resistance L armature inductance i armature current bemfv motor back emf voltage The back emf and the motor torque can be written in terms of the motor constant

mk , thus mbemf kv ikmm …………………………………………(3)

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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Combining equation (1)(2)(3) by taking Laplace Transform and eliminating variables yields the transfer function relating the output speed (s) to the input voltage sv and the load voltage ).(1 sv

sv

kRsLbsIsLRk

kRsLbsIsvks

mm

m12

12

……………...(4) The transfer function simplifies if the inductance L of the armature circuit is assumed to be small compared with the inertia of the flywheel. This gives the first order transfer function

11

1'1

'

Tssvk

Tssvks m …………………………….(5)

Where the time constant T is given by

2mkbR

IRT

2'

m

mm kbR

kk

21'

1mkbR

Rkk

Frequently we will consider the situation when the servo-control system only has an inertial load. In this case 01 sv and equation (5) simplifies to

svTs

ks m

1

'

The transfer function of the servo-motor is given by

1

1

TsG

vy ….………………………………………….(6)

Where

y : the speed sensor output voltage v : the motor drive input voltage

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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4.2 SYSTEM DYNAMICS CHARACTERISTICS : STEP RESPONSE

METHOD For a first order system like the servo-control transfer function for shaft speed, the gain 1G and time constant T can be obtained from a step response test as follows; With reference to Figure 2, the gain is determined by applying a step change, with amplitude U, to the input of a system. The final or steady state value of the output will be the product of 1GU , from which the gain can be relatively determined. The time constant T is defined as the time required for the step response of the system to reach 0.632 of its final value. This method is generally easy to use, and gives reasonable accurate results, provided the system characteristics is known o be first order.

Figure 2: Step Response

4.3 SYSTEM DYNAMICS CHARACTERISTICS : DIRECT

CALCULATION An alternative to step response testing is to measure the system characteristics individually and then use equation to calculate the gain and time constant of the process. This method requires the knowledge of the system modeling and the ability to make basic measurements of the system parameters. In practice however, the time required and inaccuracy of certain measurements mean that direct calculation of the system dynamic characteristics would only be taken if detailed simulation of the process was required.

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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4.4 ADDITIONAL THEORY

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5. EQUIPMENTS Equipment used for this experiment is;

a. CE 110 Servo Trainer b. CE 120 Controller with Chart Recorder

6. PROCEDURES 6.1 PART 1 : MOTOR DRIVE INPUT TO SPEED SENSOR OUTPUT

GAIN CHARACTERISTICS The steady state gain relating the motor drive input voltage to the speed sensor output voltage may be calculated by combining the results of Part 1 and 2 of experiment 1. Alternatively the characteristics may be measured directly as detailed in the following procedure; Connect the equipment as shown in Figure 3 (do not make the dotted connection).

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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Figure 3

1. Initial Control Settings :

i) CE 110 Clutch disengaged ii) Real Access Panel firmly closed iii) Smallest inertial load mounted (No additional discs). iv) CE 120 Potentiometer in the centre position and reading 0V

2. Increase the potentiometer voltage in steps of 1V to 9V, recording the corresponding speed sensor output (to do this disconnect the potentiometer / voltmeter connection and make the dotted connection) in Table 1.

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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3. Repeat the process for voltages -1V to -9V.

4. Repeat the procedure with the clutch engaged and enter the results in Table

2. Plot the results to obtain the required characteristics and measure the slope in order to obtain the steady state gain G.

6.2 PART 2 : MEASUREMENT OF TIME CONSTANT

1. Connect the equipment as shown in Figure 4;

2. CE110 Clutch disengaged

i) Rear access firmly closed ii) No additional inertial loads mounted

3. CE120 Potentiometer output set to 5V. Function Generator set to square wave with frequency of 0.05 Hz and level 1V. The square wave from the function generator applies a step change of 1V in either direction about the operating input of 5V. The transitions in the square wave signal provide step changes in the input. The output of the speed sensor will therefore be a series of step responses.

4. Connect the output of the speed sensor to a chart recorder and plot the step

response (suggested chart speed 10mm / second or faster. Repeat the above procedure with each of the inertial loads installed.

5. From the step responses, calculate the time constant T of the servo motor

transfer function

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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Figure 4

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7. RESULTS/OBSERVATIONS

a. Fill up Table 1 and 2. Table 1: Motor Drive Voltage / Speed sensor characteristics (Clutch Disengaged)

Motor Drive Voltage (V) (Positive)

Speed Sensor output (V)

Motor Drive Voltage (V) (Negative)

Speed sensor output (V)

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

Table 2: Motor Drive Voltage / Speed sensor characteristics (Clutch Engaged)

Motor Drive Voltage (V) (Positive)

Speed Sensor output (V)

Motor Drive Voltage (V) (Negative)

Speed sensor output (V)

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

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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7.1 OBSERVATIONS ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………………

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………………

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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7.2 CALCULATIONS PART 1: TIME CONSTANT, T OF THE SERVO MOTOR TRANSFER FUNCTION Clutch Disengaged Clutch disengaged

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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PART 2:TIME CONSTANT, T OF THE SERVO MOTOR TRANSFER FUNCTION No additional inertial loads mounted Additional inertial loads mounted

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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b. Plot the following graphs:

i) Graph 1: Motor Drive Voltage, V against Speed Sensor Output, V (Use

Table E2.1 to plot the data on the graph. Plot on the same graph the positive and negative motor drive voltage).

GRAPH 1 CALCULATION

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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GRAPH 1 ANALYSIS .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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ii) Graph 2: Motor Drive Voltage, V against Speed Sensor Output, V (Use

Table E2.2 to plot the data on the graph. Plot on the same graph the positive and negative motor drive voltage)

GRAPH 2 CALCULATION

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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GRAPH 2 ANALYSIS .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... .................................................................................................................................... ....................................................................................................................................

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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c. Analyze the printed plots form part 2. Compare the plots between with

internal load and without internal load. ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………………

UNIVERSITI TUN HUSSEIN ONN MALAYSIA Faculty of Mechanical and Manufacturing Engineering

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8. DISCUSSIONS

a. Comment on the shape of the motor drive voltage to speed sensor output

voltage characteristics. ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… b. Discuss why the time constant for various inertial loads increases as the

size of the load increases? ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………………

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c. Can you suggest ways to improve this experiment? ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………………

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9. CONCLUSION ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………………

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……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………………

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10. REFERENCES ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………………

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