servo motor control n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Servo Motor Control PowerPoint Presentation
Download Presentation
Servo Motor Control

Loading in 2 Seconds...

  share
play fullscreen
1 / 29
shauna

Servo Motor Control - PowerPoint PPT Presentation

166 Views
Download Presentation
Servo Motor Control
An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Servo Motor Control Demonstration

  2. homing switch limit switch motor with gear reducer flex coupling incremental optical encoder

  3. Closed-Loop Control How does the computer do this? computer controls the current going to the motor motor gear reducer desired steering angle compared to current steering angle gear reducer and flex couplings (if needed) connect motor to steering shaft incremental optical encoder (with homing switch to initialize position) feeds back current motor position How does the computer ‘read’ the encoder information?

  4. Computer Interface • To command the motor: • The computer must be able to generate an analog voltage signal that is somehow interpreted by the motor. • To ‘read’ the encoder: • The computer must be able to read the +5V and 0V pulses coming from the two light detectors on the optical encoder.

  5. Interface to Computer • We will use a National Instruments USB-6009 data acquisition (DAQ) device • specs • USB interface to PC • 8 channels of analog input, 0-5V • 2 channels of analog output 0-5V5 mA each • 12 channels of digital input/outputs0 or 5V, (8.5 mA for outputs) • 1 counter

  6. NI USB-6009

  7. Interface to Computer

  8. Honeywell / Clarostat 600128CN1 Allied Electronics part # 753-0059 cost: $41.67

  9. Computer Interface • Let’s start with digital inputs to interface to the optical encoder. notice that there are four wires

  10. channels A & B will be either 0V or 5V depending on whether that light detector detects light through a slit or not ground channel A channel B +5V power

  11. ground channel A channel B +5V power

  12. Encoder Demo Program

  13. Closed-Loop Control How does the computer do this? computer controls the current going to the motor motor gear reducer desired steering angle compared to current steering angle gear reducer and flex couplings (if needed) connect motor to steering shaft incremental optical encoder (with homing switch to initialize position) feeds back current motor position

  14. Computer Interface to Motor • To control the motor: • the computer must be able to generate an analog voltage signal • however, the typical analog voltage signal that a computer generates does not have sufficient current to power the motor • an amplifier is used • a power supply provides 24V (7.5 amp max for our case) to the amp • the computer generates an analog voltage in the range of-5V to +5V; 0V means the motor is to stop ; -5V means the motor is to turn at a maximum speed CCW ; +5V means the motor is to turn at a maximum speed CW

  15. Interface to Computer

  16. command analog signal emergency stop to motor from 24V power supply

  17. Issue with USB-6009 & Amp The analog command signal to the amp must be from -5V to +5V. A negative voltage causes the motor to turn in the opposite direction. The USB DAQ can only output from 0 to +5V. How can we reverse the direction of the motor?

  18. When we want the motor to go in the other direction, switch these two wires. command analog signal emergency stop to motor from 24V power supply

  19. Change motor direction To go CW, set this digital output pin to TRUE (+5V). To go CCW, set this digital output pin to FALSE (0V).

  20. Interface to Computer

  21. Interface to Computer

  22. Homing Switch 0V +5V to input pin on USB DAQ

  23. Interface to Computer 0V from USB-6009 +5V from USB-6009

  24. digital signal E stop switch input power analog signal computer controls the current going to the motor USB connection desired steering angle compared to current steering angle gear reducer and flex couplings (if needed) connect motor to steering shaft USB connection incremental optical encoder (with homing switch to initialize position) feeds back current motor position digital signal homing switch 2 digital signals

  25. Design Project • If you decide to use a servo motor in your design: • include an optical encoder for motor position feedback • include a homing switch to initialize your position • include E-stop switches as needed