Student ID: A0066028HANNEX AName: Lee Men KengCourse: Bachelor of Technology (Mechanical & Manufacturing Engineering)

M2142E FEEDBACK CONTROL SYSTEMSSPEED / POSITION CONTROL OF A DC MOTOR

SUBMISSION OF LAB REPORT

NAME:LEE MEN KENG

STUDENT ID:A0066028H

DATE:2 April 2012

Objectives

The objective of the experiment is to:a) Become familiar with the operation of an armature-controlled DC motorb) Study the transient and steady state response of a closed-loop speed control system;c) Study the transient response of a closed-loop position control system

ResultsTable 1: TACHO-GENERATOR CHARACTERISTICSSpeed (rpm)400800120016002000

Tacho Output (volts)1.162.333.494.665.82

Do with speed feedback (to make speed easily controlled)Speed range is 400rpm to 2000rpm in increments of approximately 400 rpm.Gain = 0.1

Table 2A: Brake Setting=0 (No feedback) Gain=0.1MOTOR CHARACTERISTICS-SPEED VS INPUT

Speed (rpm)400800120016002000

Volts (mV)152.5194.7235.89273.67313.4

Speed range is 400 rpm to 2000 rpm in increments of approximately 400 rpm

Table 2B: Brake Setting=2 (No feedback) Gain=0.1MOTOR CHARACTERISTICS-SPEED VS INPUT

Speed (rpm)400800120016001850

Volts (mV)156.52202.18248.78296.68355.68

Speed range is 400 rpm to 2000 rpm in increments of approximately 400 rpm

Table 2C: Brake Setting=4 (No feedback) Gain=0.1MOTOR CHARACTERISTICS-SPEED VS INPUT

Speed (rpm)40080012001400

Volts (mV)163.35222.42278.52319.43

Speed range is 400 rpm to 2000 rpm in increments of approximately 400 rpm

ResultsTable 3: OPEN-LOOP LOAD-SPEED CHARACTERISTICS (NO FEEDBACK)

Brake Setting0246810

Speed (Gain = 0.02)1000840700610430400

Speed (Gain = 0.05)1000830700610490450

Speed (Gain = 0.1)1000850700610490450

For each gain setting, start with speed of about 1000rpm at zero brake scale reading

NoteGain = 0.02, Set 2 in Attenuator Unit (AU150B)Gain = 0.05, Set 5 in Attenuator Unit (AU150B)Gain = 0.1, Set 10 in Attenuator Unit (AU150B)

Table 4: CLOSED-LOOP LOAD-SPEED CHARACTERISTICS (WITH SPEED FEEDBACK)

Brake Setting0246810

Speed (Gain = 0.02)1000900730690580550

Speed (Gain = 0.05)1000930840780690660

Speed (Gain = 0.1)1000960900860780760

For each gain setting, start with speed of about 1000rpm at zero brake scale reading

ResultsTable 5: CLOSED-LOOP SPEED CONTROL TRANSIENT RESPONSE (WITH SPEED FEEDBACK)Brake SettingBrake = 5Brake = 10Remarks

Overshoot %Settling Time, msRise Time, msOvershoot %Settling Time, msRise Time, ms

Speed (Gain = 0.02)0846805244

Speed (Gain = 0.05)0136120012492

Speed (Gain = 0.1)02001520124100

Settling Time, within 5% of steady state valueRise Time, Time to reach steady state value at the first instance

Table 6: CLOSED-LOOP SPEED CONTROL TRANSIENT RESPONSE (WITH SPEED FEEDBACK)Brake Setting = 5With Speed FeedbackNo Speed FeedbackRemarks

Overshoot %Settling Time, msRise Time, msOvershoot %Settling Time, msRise Time, ms

Speed (Gain = 0.02)05605100550500

Speed (Gain = 0.05)06705700330280

Speed (Gain = 0.1)05104706.15190170

Settling Time, within 5% of steady state valueRise Time, Time to reach steady state value at the first instance

Charts

Charts

Chart 4Closed Loop Speed Control Transient Response for Gain=0.10 and Brake=5

Chart 5Closed Loop Speed Control Transient Response for Gain=0.05 and Brake=5

Chart 6Closed Loop Speed Control Transient Response for Gain=0.02 and Brake=5Chart Chart 7Closed Loop Speed Control Transient Response for Gain=0.02 and Brake=10

Chart 8Closed Loop Speed Control Transient Response for Gain=0.05 and Brake=10

Chart 9 Closed Loop Speed Control Transient Response for Gain=0.10 and Brake=10

Chart 10Closed Loop Position Control System (with Speed Feedback) for Gain=0.10 and Brake=5

Chart 11Closed Loop Position Control System (with Speed Feedback) for Gain=0.05 and Brake=5

Chart 12Closed Loop Position Control System (with Speed Feedback) for Gain=0.02 and Brake=5

Chart 13Closed Loop Position Control System (without Speed Feedback) for Gain=0.02 and Brake=5

Chart 14Closed Loop Position Control System (without Speed Feedback) for Gain=0.05 and Brake=5

Chart 15Closed Loop Position Control System (without Speed Feedback) for Gain=0.10 and Brake=5

Discussion

Differences in open-loop and closed loop control

With the results obtained from Table 3 OPEN-LOOP LOAD-SPEED CHARACTERISTICS (NO FEEDBACK) there are very little to no changes to the speed when the gain changes.

Whereas for Table 4: CLOSED-LOOP LOAD-SPEED CHARACTERISTICS (WITH SPEED FEEDBACK), we observed that the closed loop control introduce more changes and variation in their response to different gain variants.

Closed loop system will provide better accuracy as compared to open loop systems, and also less sensitive to disturbances, as it react to transient response and error.

Effect of loop gain and brake scale settings

Apparently, the difference between rise time and settling time is getting wider when increasing the brake settings for the lower and higher gains, except gain at 0.05 when it seems the time response is constant with both brake settings. Hence, to ensure constant time response, there is an optimum gain. Effect of loop gain and velocity feedback

There is an overshoot of 6.15% at gain 0.1 with no feedback.Therefore we can see that the damping effect of the closed loop system help to prevent overshoot.

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