![](/media/cache/group/default_image.jpg.50x50_q85.jpg)
control for robotic arm that can play chess using a granular gripper
Dependencies: Encoder mbed HIDScope Servo MODSERIAL
Fork of chessRobot by
actuators.cpp
- Committer:
- annesteenbeek
- Date:
- 2015-10-28
- Revision:
- 117:b1667291748d
- Parent:
- 116:8b812e268b85
- Parent:
- 112:7b964afb97b4
- Child:
- 118:49605b5bd802
File content as of revision 117:b1667291748d:
#include "actuators.h" #include "PID.h" #include "mbed.h" #include "config.h" #include "encoder.h" #include "HIDScope.h" #include "buttons.h" #include "Servo.h" // Motor control constants #define pwm_frequency 50000 // still High, could be lowered #define PI 3.14159265 // functions for controlling the motors bool motorsEnable = false; bool safetyOn = true; double encoder1Counts = 0; double encoder2Counts = 0; bool direction1 = false; // CCW is false(positive rotation), CW is true (neg rotation) bool direction2 = false; double motor1Pos = 0; double motor2Pos = 0; double motor1Speed = 0; double motor2Speed = 0; double motor1SetSpeed = 0; double motor2SetSpeed = 0; double motor1PWM = 0; double motor2PWM = 0; // Set PID values double Kp1 = 1; double Ki1 = 0; double Kd1 = 0; double Kp2 = 0.008; double Ki2 = 0.08; double Kd2 = 0; double motor1PrevCounts = 0; double motor2PrevCounts = 0; double prevTime = 0; double now = 0; double timechange; // Set servo values double servoSpeed = 0; const int servoStartPos = 1300; // Servo ranges from 600ms(-90) to 2000ms(90), 1300 is 0 deg // Set calibration values double motor1CalSpeed = -5; // deg/sec double motor2CalSpeed = 5; bool springHit = false; float lastCall = 0; bool calibrating1 = true; bool calibrating2 = false; double looseTime = 0; bool calReady = false; // Create object instances // Safety Pin DigitalIn safetyIn(safetyPin); // Initialze motors PwmOut motor1(motor1PWMPin); PwmOut motor2(motor2PWMPin); // initialize Servo Servo servo(servoPin); // Initialize encoders Encoder encoder1(enc1A, enc1B); Encoder encoder2(enc2A, enc2B); // Set direction pins DigitalOut motor1Dir(motor1DirPin); DigitalOut motor2Dir(motor2DirPin); // create PID instances PID motor1PID(&motor1Speed, &motor1PWM, &motor1SetSpeed, Kp1, Ki1, Kd1); PID motor2PID(&motor2Speed, &motor2PWM, &motor2SetSpeed, Kp2, Ki2, Kd2); Timer t; void motorInit(){ motor1Dir.write(direction1); motor2Dir.write(direction2); // Set motor PWM period motor1.period(1/pwm_frequency); motor2.period(1/pwm_frequency); motor1PID.SetSampleTime(motorCall); motor2PID.SetSampleTime(motorCall); motor1PID.SetOutputLimits(0,1); motor2PID.SetOutputLimits(0,1); // Turn PID on motor1PID.SetMode(AUTOMATIC); motor2PID.SetMode(AUTOMATIC); // set servo period servo.Enable(servoStartPos, 20000); // start the timer t.start(); } void motorControl(){ // EMG signals to motor speeds // const double scaleVel = 20; // motor1SetSpeed = x_velocity*scaleVel; // motor2SetSpeed = y_velocity*scaleVel; // servoSpeed = z_velocity*scaleVel; // get encoder positions in degrees // 131.25:1 gear ratio // getPosition uses X2 configuration, so 32 counts per revolution // encoder reads CCW negative, and CW positive, so multiply by -1 to make CCW positive encoder1Counts = encoder1.getPosition(); encoder2Counts = encoder2.getPosition(); motor1Pos = ((encoder1Counts/32)/131.25)*360; motor2Pos = ((encoder2Counts/32)/131.25)*360; // check if motor's are within rotational boundarys // get encoder speeds in deg/sec now = t.read(); timechange = (now - prevTime); motor1Speed = ((((encoder1Counts - motor1PrevCounts)/32)/131.25)*360)/timechange; motor2Speed = ((((encoder2Counts - motor2PrevCounts)/32)/131.25)*360)/timechange; prevTime = now; motor1PrevCounts = encoder1Counts; motor2PrevCounts = encoder2Counts; // calculate motor setpoint speed in deg/sec from setpoint x/y speed // exclude kinematics when still calibrating if (calReady){ kinematics(); } if(motorsEnable){ // only run motors if switch is enabled // compute new PID parameters using setpoint angle speeds and encoder speed writeMotors(); servoControl(); }else{ // write 0 to motors motor1.write(0); motor2.write(0); } } void writeMotors(){ motor1PID.Compute(); // calculate PID outputs, output changes automatically motor2PID.Compute(); // write new values to motor's if (motor1SetSpeed > 0 ){ // CCW rotation direction1 = true; motor1PID.SetOutputLimits(0,1); // change pid output direction }else{ direction1 = false; // CW rotation motor1PID.SetOutputLimits(-1,0); } if (motor2SetSpeed > 0 ){ // CCW rotation direction2 = true; motor2PID.SetOutputLimits(0,1); }else{ direction2 = false; // CW rotation motor2PID.SetOutputLimits(-1,0); } motor1Dir.write(direction1); motor2Dir.write(direction2); motor1.write(abs(motor1PWM)); motor2.write(abs(motor2PWM)); } void servoControl(){ servo.SetPosition(1300 + 700*servoSpeed); } const double motor1StartPos = (-10*32*131.25)/360; // angle to encoder counts const double motor2StartPos = (114*32*131.25)/360; bool calibrateMotors(){ safetyOn = false; // safety springs off motorsEnable = true; // motors on while (calibrating1 || calibrating2){ if (calibrating1){ motor1SetSpeed = motor1CalSpeed; redLed.write(1); greenLed.write(0); blueLed.write(1); if(safetyIn.read() !=1 && !springHit){ // check if arm reached safety position encoder1.setPosition(motor1StartPos); // set motor 1 cal angle motor1PrevCounts = motor1StartPos; // set previous count to prevent speed spike motor1CalSpeed = -motor1CalSpeed; // move away springHit = true; looseTime = t.read(); // timer to compensate spring movement }else{ // if hit and after is no longer touching spring and 0.5seconds passed if(springHit && ((t.read() - looseTime) > 2)){ motor1SetSpeed = 0; springHit = false; calibrating2 = true; // start calibrating 2 calibrating1 = false; } } } if (calibrating2){ motor2SetSpeed = motor2CalSpeed; redLed.write(1); greenLed.write(1); blueLed.write(0); if(safetyIn.read() !=1 && !springHit){ // check if arm reached safety position encoder2.setPosition(motor2StartPos); // set motor 2 cal angle motor2PrevCounts = motor2StartPos; // set previous cunt to prevent speed spike motor2CalSpeed = -motor2CalSpeed; // move away springHit = true; looseTime = t.read(); }else{ if(springHit && ((t.read() - looseTime) > 2)){ motor2SetSpeed = 0; springHit = false; calibrating2 = false; // stop calibrating 2 } } } // now = t.read(); // call motor using timer instead of wait // if(now - lastCall > motorCall){ motorControl(); wait(motorCall); // keep calling PID's with motorCall frequency // lastCall = now; // } } redLed.write(0); greenLed.write(1); blueLed.write(1); motorsEnable = false; // turn motor's off again safetyOn = true; // turn safety on after callibration return true; // return true when finished } void safety(){ if (safetyOn){ if (safetyIn.read() != 1){ motorsEnable = false; } } } const double L1 = 0.436; // first arm in m const double L2 = 0.120; // first arm in m const double L3 = 0.255; // servo arm in m const double Xmax = 0.3; const double Xmin; = -0.3; const double Ymax = 0.645; const double Ymin = 0.33; bool kinematics(){ // calculate current x and Y double X = (L2+L3)*cos((motor1Pos + motor2Pos)*PI/180) + L1*cos(motor1Pos*PI/180); double Y = (L2+L3)*sin((motor1Pos + motor2Pos)*PI/180) + L1*sin(motor1Pos*PI/180); // check if x and y are within limits // else Store the constraint line // check if movement is in direction of constraint // else return false no movement (anglespeed = 0) // calculate required angle speeds if( (X>Xmax && setXSpeed > 0 )|| \ (X<Xmin && setXSpeed < 0 )|| \ (Y>Ymax && setYSpeed > 0 )|| \ (Y<Ymin && setYSpeed < 0 ) \ ){ motor1SetSpeed = 0; motor2SetSpeed = 0; return false; break; } motor1SetSpeed = (setXSpeed*cos((motor1Pos + motor2Pos)*PI/180) + \ setYSpeed*sin((motor1Pos + motor2Pos)*PI/180))/(L1*sin(motor2Pos*PI/180)); motor2SetSpeed = -(setXSpeed*(L2+L3)*cos((motor1Pos + motor2Pos)*PI/180) + \ setYSpeed*(L2+L3)*sin((motor1Pos + motor2Pos)*PI/180) + \ setXSpeed*L1*cos(motor1Pos*PI/180) + \ setYSpeed*L1*sin(motor1Pos*PI/180))/(L1*(L2+L3)*sin(motor2Pos*PI/180)); }