1. 1 Motors & Motor Controllers ECE 450

2. 2 AC or DC Motors AC –Few robots use AC except in factories –Most of those that use AC first convert to DC DC –Dominates in robotics –Must be bidirectional

3. 3 DC Motor Types Continuous-duty (run continuously when power supplied) –Brushed –Brushless –Servo Intermittent-duty (power must be pulsed to run continuously) –Stepper Motors

4. 4 Motor Specifications Operating voltage Current draw Speed Torque Stalling or Running Torque

5. 5 DC Motor: Brush Motors Brushes Stator (permanent magnets) The most common. Toys, battery powered tools, electric machines.

6. 6 Brush DC Motors Identify: Stator Rotor Brushes Commentator Permanent Magnets Armature Field http://mot-sps.com/motor/tutorial/blac.html Electrical Engineering Terms: Armature: The power-producing component of an alternator, generator, dynamo or motor. The armature can be on either the rotor or the stator. Field: The magnetic field component of an alternator, generator, dynamo or motor. The field can be on either the rotor or the stator and can be either an electromagnet or a permanent magnet.

7. 7 Brush DC Motor How does it work?

8. 8 Pulse Width Modulation (PWM) Centered PWM

9. 9 Brushless DC Motor http://mot-sps.com/motor/tutorial/blac.html Identify: Permanent Magnets Rotor Brushes Commentator Armature Field

10. 10 Brushless DC Motor 1.Laminated steel stack 2.Winding 3.Shaft 4.Permanent Magnets Less common. Higher efficiency, less friction, less electrical noise. Requires electronic driver.

11. 11 Brushless DC Motor How does it work?

12. 12 DC Servo Motor http://www.societyofrobots.com/actuators_servos.shtml A DC Servo Motor is a DC Motor with Gears and Electronics with limited angular rotation (typically 90, 180 or 360º) Why the addition of gears? Nylon Karbonite Metal Why electronics? Digital Analog

13. 13 DC Servo Motor http://www.seattlerobotics.org/guide/servos.html 2.00 ms 1.50 ms 1.00 ms 0.50 ms 0.00 ms 0 1 2.00 ms 1.50 ms 1.00 ms 0.50 ms 0.00 ms 0 1 2.00 ms 1.50 ms 1.00 ms 0.50 ms 0.00 ms 0 1 1.50 ms: Neutral 1.00 ms: 0 degrees 2.00 ms: 180 degrees Requires constant pulsing (  50 times / second)

14. 14 DC Servo Motor Wiring to Microcontroller Servo motors have three wires: power, ground, and signal. 1.The ground wire is typically black or brown and should be connected to a ground. 2.The power wire is typically red, and should be connected to the voltage source. 3. The signal pin is typically yellow, orange or white and should be connected to the microcontroller

15. 15 Stepper Motors http://www.stepperworld.com/Tutorials/pgUnipolarTutorial.htm * An 8 lead stepper is wound like a unipolar stepper, but the leads are not joined to common internally to the motor. Unipolar*Bipolar Very common. Required driver. Very strong, when not rotating. Easy to control rotor position. The stepper motor rotates in set angles for each pulse received. Typical angles are turns 30º, 15º and 7.5º.

16. 16 Stepper Motor Controllers With the appropriate logic, step motors can be bi-directional, synchronous, provide rapid acceleration, stopping, and reversal, and will interface easily with other digital mechanisms. They are further characterized as having low rotor moment of inertia, no drift, and a noncumulative positioning error. Generally step motors are operated without feedback in an open-loop fashion and sometimes match the performance of more expensive DC Servo Systems. The only inaccuracy associated with a step motor is a noncumulative positioning error measured in % of step angle. http://www.anaheimautomation.com/intro.htm http://arduino.cc/en/Reference/StepperUnipolarCircuit

17. 17 Stepper Motor Very common. Required driver. Very strong, when not rotating. Easy to control rotor position. Full StepHalf Step http://mot-sps.com/motor/tutorial/blac.html

18. 18 1 1 1 Full-Step Stepper Motor 1

19. 19 Half-Step Stepper Motor 1 1 1 1 1

20. 20 Using an Atmel Tiny2313 and SN754410 H-Bridge http://www.instructables.com/id/Drive-a-Stepper-Motor-with-an-AVR-Microprocessor/

21. 21 Motor Drivers Simple, 1- dc motor (brushes), on/off driver D1 1N5817 (Schottky) M M1 DC Brush +9 V Q1 2222A (NPN) R1 1 k  On: to +9 V Off: to GND or disconnected B E C

22. 22 Transistors NPN Bipolar Transistor PNP Bipolar Transistor C B E C B E http://www.kilowattclassroom.com/Archive/AN0007.pdf

23. 23 DC Brushed Motor Drivers Simple, 1-motor, on/off driver D1 1N5817 (Schottky) M M1 DC Brush +9 V Q2 2907A (PNP) R2 1 k  On: to GND or disconnected Off: to +9 V B C E

24. 24 Motor Drivers Classic Bipolar H-Bridge On: to +9 V Off: to GND or disconnected On: to +9 V Off: to GND or disconnected On: to GND or disconnected Off: to +9 V On: to GND or disconnected Off: to +9 V D1 1N5817 (Schottky) M M1 DC Brush +9 V Q2 2907A (PNP) R2 1 k  B C E R1 1 k  D2 1N5817 (Schottky) Q1 2222A (NPN) +9 V Q4 2907A (PNP) R4 1 k  B C E R3 1 k  Q3 2222A (NPN) D3 1N5817 (Schottky) D4 1N5817 (Schottky) B E C B E C Taken from Intermediate Robot Building by David Cook Terminal 1 Terminal 2 Terminal 3 Terminal 4

25. 25 Motor Drivers Classic Bipolar H-Bridge D1 1N5817 (Schottky) M M1 DC Brush Q2 2907A (PNP) R2 1 k  B C E R1 1 k  D2 1N5817 (Schottky) Q1 2222A (NPN) Q4 2907A (PNP) R4 1 k  B C E R3 1 k  Q3 2222A (NPN) D3 1N5817 (Schottky) D4 1N5817 (Schottky) B E C B E C 4427 1 2 3 4 8 7 6 5 NC GND IN A IN B NC V DD OUT A OUT B +9 V from microcontroller GND Taken from Intermediate Robot Building by David Cook

26. 26 Motor Drivers Typical H-Bridge Motor Driver M M1 DC Brush OUT B +5 VDC Disconnected or from microcontroller From microcontroller SN754410 1 2 3 4 ENABLE A&B OUTPUT A INPUT A GND 5 6 7 8 INPUT B OUTPUT B V MOTOR V LOGIC OUTPUT C INPUT C GND INPUT D OUTPUT D ENABLE C&D 16 15 14 13 12 11 10 9 M from microcontroller M2 DC Brush Disconnected or from microcontroller From microcontroller 0.1  F 220  F +4.5 to +36 VDC 0.1  F 220  F Taken from Intermediate Robot Building by David Cook