IntroductionBackground ReadingExperiment 1a: Open Loop Control of DC Motor VelocityGround on DC power supply*Experiment 2a: Proportional (P) Control of DC Motor VelocityWire colorExperiment 3a: Integral (I) Control of DC Motor VelocityLaboratory ReportME 104 Sensors and Actuators Laboratory 6a Closed Loop Analog Control Of DC Motor Velocity Department of Mechanical Engineering University of California, Santa Barbara (Rev. 2007)Introduction In this laboratory, you will build analog circuits on a breadboard to implement proportional (P) and integral (I) control of a DC motor. NOTE: • For this lab, you will need yourname_MotorDrive_AcquireVoltage.vi which you created for Lab 4. • You will write ONE REPORT FOR EACH Labs 6a and 6b. Background Reading Please read the following material prior to this lab: 1. Histand and Alciatore, Introduction to Mechatronics, Sections 5.1-5.8 and Sections 5.10-5.11. 2. DC Motor Control Module User Manual, Pages 3-7 and 14-16, LJ Technical Systems Inc. Experiment 1a: Open Loop Control of DC Motor Velocity In this experiment, you will use a LabVIEW VI to drive a DC motor, similar to what you did in Laboratory #4. You will observe both the motor drive input VIN and the tachogenerator output VOUT (velocity feedback) on an oscilloscope. Figure 1. Open loop control of DC motor velocity Velocity SensorDrive CircuitsDC MotorDC Motor Module DAQ boardPC D/A Converter VINVOUTShaft RotationCh. 1 Ch. 2 Oscilloscope 2In control system terminology, the system shown in Figure 1 is described as an open loop control system. This is because the control (drive) signal VIN to your plant (the DC motor module) does not directly (automatically) depend on the output signal VOUT. Figure 2 shows the open loop control system in block diagram form in which the following notation has been used: P(s) = Plant (DC Motor module)*I = Identity block (D/A Converter) rVI = reference signal from LabVIEW VI r = reference signal u = control input to VIN socket on Motor Drive Input panel y = plant output from VOUT socket on Tachogenerator Output panel I Plant P(s) r y rV Iu Figure 2. Open loop control block diagram The D/A converter is represented by an identity block to indicate that the reference value seen by your system should be equal to the reference value specified by your LabVIEW VI. For this experiment, you will drive the DC motor such that the reference value is equal to the control input. That is, r = u. 1. Set the appropriate switches on your DC motor control module so that you can drive the motor with analog voltage input and also obtain analog velocity feedback from the tachogenerator output. • MOTOR DRIVE switch: VIN position – selects analog motor drive input • TACHOGENERATOR switch: VOUT position – enables analog velocity feedback output 2. Use a banana connector to connect the E (Enable Input) socket to the 0V socket to enable the input to drive the motor. 3. Connect the 0V sockets (Analog ground) on MOTOR DRIVE INPUT panel and TACHOGENERATOR OUTPUT panel to common ground. * The P(s) notation indicates that the Plant is represented mathematically by its transfer function. 34. To drive the motor using the analog voltage output from the DAQ board, connect your motor control module to the CB-68LP connector block according to Table 1. Table 1. CB-68LP connector block pin assignments for open loop control of DC motor velocity. DC Motor Control Module Connect to: VIN socket (Analog voltage) on MOTOR DRIVE INPUT panel AO0 VOUT socket (Analog voltage) on TACHOGENERATOR OUTPUT panel AI0 Ground on DC power supply* AIGND Ground on DC power supply* AOGND *The connector block can also be grounded to the breadboard if the breadboard is grounded to the DC power supply. 5. Before connecting the DC power supply to the motor module, turn ON the DC power supply and make sure the variable output terminals are properly configured to provide –12 V and +12 V. 6. Turn OFF the DC power supply, then connect the power supply to the DC motor module. 7. Make sure that no wires or cables interfere with the moving parts of your motor. 8. Turn ON the DC Power Supply. 9. Make sure the Eddy Current Brake is disengaged. That is, make sure it is in the 0 position. 10. Connect your DC motor control module to your oscilloscope such that the reference r ( = VIN ) is viewed on Channel 1 and the velocity feedback VOUT ( = y) is viewed on Channel 2. For best viewing, set your vertical scales to 1volt/division and your horizontal scale to 400 ms/division. 11. Open and run yourname_MotorDrive_AcquireVoltage.vi (created for Lab 4) by clicking the Run Continuously button. Incrementing by units of 1.00 V from -4.00 V to +4.00 V (inclusive) for the Motor Drive Input Control, observe the voltage signals on Channels 1 and 2 of your oscilloscope.* For each increment, make a sketch of the transient behavior and write down the steady state† values of r and VOUT (as displayed by the digital indicators on your VI front panel). 12. Set the Eddy Current Brake to the 1 position and repeat Step 7. This brake acts as an external disturbance to your system. 13. Set your Motor Drive Input Control to 0.00 and stop running the VI by clicking the Abort Execution (stop) button. * To avoid saturation effects, the boundary reference values of [–5.00 V to 5.00 V] is reset to [-4.00 V to 4.00V]. † “Steady state” means that you have waited long enough that transient motion has ceased. 4Although one would like (and expect) VIN ( = y) and VOUT ( = r ) to be equal, you should have observed that they are not equal, except when VIN = 0V. That is, your plant P(s) has a steady-state error for nonzero reference values. In other words, in the absence of output information, the magnitude of your plant (motor) velocity is slightly different from what you would like it to be. This situation can be improved using closed loop (feedback) control. Experiment 2a: Proportional (P) Control of DC Motor Velocity In this experiment, you will use a LabVIEW VI and a proportional (P) feedback control circuit to control a DC motor. Figure 3 shows the closed loop control system in block diagram form in which the following notation has been used: P(s) = Plant (DC Motor module) K(s) = Controller I = Identity block (D/A Converter) rVI = reference signal from LabVIEW (VI) r = reference signal e = error signal = r - y u = control input to VIN