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wait(20, msec);
}
wait(20, msec); //allow time for status update to draw itself
//graph the PID at the end
drawMode = 1;
graphPID(errorHistory, powerHistory, driveDistance, error1, time);
LeftMotors.stop();
RightMotors.stop();
return 0;
}
int turnPID() {
//drive straightforward with driveDistance as the distance, in degrees (for now)
//forward PID constants:
//zieger-nicholas on 11/14: ku = .07 period = .5 sec
float kP1 = 0.034;//.0245;//.0225 and 0 for other two
float kI1 = 0.0037;//0.0017; //0.0017
float kD1 = 0.19;//0.06;//0.010;
//not bad; 0.017, 0.0042, 0
//not bad v2; .04, 0.0037, 0.23
//other variables for forward PID
float error = 0;
float integral = 0;
float derivative = 0;
float prevError = 0;
//motor power variables
float motorPower = 0;
float prevMotorPower = 0;
//lists
std::vector<int> errorHistory; //keep track of error over time
std::vector<float> powerHistory; //keep track of motor power over time
int time = 0;
float currentDist = 0; //the distance the robot is from its starting point, rotationally
float startDist = (Inertial1.rotation(degrees) + Inertial2.rotation(degrees)) / 2;
//Inertial1.setHeading(0, degrees);
//Inertial2.setHeading(0, degrees);
//float degOffset
while(true) {
//float deg1 = Inertial1.heading(degrees);
currentDist = (Inertial1.rotation(degrees) + Inertial2.rotation(degrees)) / -2 + startDist;
//printController(Inertial1.rotation(degrees));
//calculate error / integral / derivative, of error vs time graph
error = driveDistance - currentDist;
if (std::abs(error) < 8) {
//weigh the integral double when error < 4
if (std::abs(error) < 3) {
integral += error * 2;
} else {
integral += error;
}
} else {
integral = 0;
}
derivative = error - prevError;
//core of the PID loop here, calculate the necessary motor power, combine both PID loops
motorPower = (kP1 * error + kI1 * integral + kD1 * derivative);
///keep motor power variable in proper range, -1 to 1
if (motorPower > 1) motorPower = 1;
if (motorPower < -1) motorPower = -1;
//control the slew rate (dampen voltage differences), limits harsh acceleration
float slewRate = 0.08f;
if (motorPower > prevMotorPower + slewRate) {
motorPower = prevMotorPower + slewRate;
}
if (motorPower < prevMotorPower - slewRate) {
motorPower = prevMotorPower - slewRate;
}
//minimum voltage of 11V * .2
/*if (std::abs(slewRate) != .12) {
if (std::abs(motorPower) < 0.2) {
if (motorPower > 0) {
motorPower = 0.2;
} else {
motorPower = -0.2;
}
}
}*/
//apply motor voltages
LeftMotors.spin(forward, 11 * motorPower * -1, volt);
RightMotors.spin(forward, 11 * motorPower, volt);
//update histories
errorHistory.push_back(error);
powerHistory.push_back(motorPower);
time += 20;
//update final variables
//printController(error);
//break out of the loop if we have reached the target or B is pressed
//we have reached the target if the error is less than 5 and the previous error is similar
if (Controller1.ButtonB.pressing() || ((std::abs(error) < 0.5) && std::abs(error - prevError) < 0.3)) {
break;
}
prevMotorPower = motorPower;
prevError = error;
//don't hog CPU
wait(20, msec);
}
wait(20, msec); //allow time for status update to draw itself
//graph the PID at the end
drawMode = 1;
graphPID(errorHistory, powerHistory, driveDistance, error, time);
LeftMotors.stop();