DC MOTOR CONTROL SYSTEMS FOR ROBOT APPLICATIONS By: Rick Bickle 11/7/2003 Motor control questions  Why do we need speed control?  How is DC motor speed controlled?  How is motor direction controlled?  What circuits can be used? Reasons for accurate speed control  Motor speed should be independent of load.  Differential drive platforms need to synchronize wheel speed to go in a straight line. Speed control with PWM  Pulse Width Modulation Simple PWM circuit U1A 74HC14A 1 2 U1B 74HC14A 3 4 U1C 74HC14A 5 6 U1D 74HC14A 9 8 U1E 74HC14A 11 10 U1F 74HC14A 13 12 C1 CAP NP D1 DIODE D2 DIODE R2 POT 1 3 2 MG1 MOTOR DC 1 2 H-Bridge motor driver circuit V+ V+ +5 +5 +5 +5 M1 DC Motor Q1 IRF9510 Q5 2N2222 Q8 2N2222 R6 4.7K R2 4.7K R1 4.7K R3 4.7K R5 4.7K U1C 74HC08 9 10 8 14 7 U1B 74HC08 4 5 6 14 7 Q4 IRF510 U1C 74HC08 9 10 8 14 7 R4 4.7K Q6 2N2222 Q2 IRF9510 Q3 IRF510 U1A 74HC08 1 2 3 14 7 Q7 IRF510 Input A Input B PWM Input CIRCUIT INPUTS SS SS D DD D G GG G A B C Output 0 0 0 N Channel Brake 1 1 0 P Channel Brake 1 0 0 Forward 0 1 0 Reverse X X 1 Motor Off D G S Optical encoder circuit U6B 74HC86 4 5 6 R6 4.7K R7 4.7K D4 5V D3 5V R9 4.7K D6 5V D5 5V R8 4.7K U6A 74HC86 1 2 3 U6D 74HC86 12 13 11 U6C 74HC86 9 10 8 R10 10K C15 0.001uF C14 0.001uF R11 10K U27A 74HC14 1 2 U27B 74HC14 3 4 U27D 74HC14 9 8 U27C 74HC14 5 6 U27F 74HC14 13 12 U27E 74HC14 11 10 Tach Input A Tach Input B Tach Input A Tach Input B L. MotorR. Motor Motor control diagram PROCESSOR DC MOTOR ENCODER H-BRIDGE CIRCUIT Control systems  What is a control system?  What are some examples?  What are the types of control systems?  How are control systems represented? Open loop control systems  The output of the plant does not affect the input. (No feedback)  Less common today than closed loop control systems.  Examples include:  Stereo volume control  Electric drill speed control [...]... This allows the response of the platform to be determined numerically PID Brute Force Tuning code The tuning algorithm loops through a range of values for each coefficient P, I, and D For example: for (P=P_start; P . DC MOTOR CONTROL SYSTEMS FOR ROBOT APPLICATIONS By: Rick Bickle 11/7/2003 Motor control questions  Why do we need speed control?  How is DC motor speed controlled?  How is motor direction. Input B L. MotorR. Motor Motor control diagram PROCESSOR DC MOTOR ENCODER H-BRIDGE CIRCUIT Control systems  What is a control system?  What are some examples?  What are the types of control systems? . cruise control Closed loop control system GAIN INPUT PLANTSUM FEEDBACK OUTPUT = (INPUT – OUTPUT) X GAIN Motor control diagram PROCESSOR DC MOTOR ENCODER H-BRIDGE CIRCUIT PID Closed loop control