Task 3: Integrate the Motor Driver

Objective

Convert the PID output into a valid actuator command that safely drives the motor or servo controlling the beam.

Implementation Guidance

• Map the PID output to a PWM value or servo angle
• Respect mechanical angle limits of the beam
• Ensure smooth transitions when switching motor direction
• Test actuator response independently before running full PID control
• Add safety constraints to prevent sustained maximum output

For Servo Motor:

// actuator.h#ifndef ACTUATOR_H#define ACTUATOR_Hvoid initActuator();void setBeamAngle(float pidOutput);

#endif

// actuator.cpp#include "actuator.h"#include Servo beamServo;const int SERVO_PIN = 9;const int CENTER_ANGLE = 90;const int MAX_DEFLECTION = 30;  // +/- 30 degrees from centervoid initActuator() {    beamServo.attach(SERVO_PIN);    beamServo.write(CENTER_ANGLE);}

void setBeamAngle(float pidOutput) { // Map PID output (-255 to 255) to angle deflection float deflection = map(pidOutput, -255, 255, -MAX_DEFLECTION, MAX_DEFLECTION); // Calculate final angle int angle = CENTER_ANGLE + (int)deflection; // Enforce limits if (angle > CENTER_ANGLE + MAX_DEFLECTION) angle = CENTER_ANGLE + MAX_DEFLECTION; if (angle < CENTER_ANGLE - MAX_DEFLECTION) angle = CENTER_ANGLE - MAX_DEFLECTION; beamServo.write(angle);}

For DC Motor with H-Bridge:

void setMotorOutput(float pidOutput) {    int pwmValue = abs((int)pidOutput);    if (pwmValue > 255) pwmValue = 255;        if (pidOutput > 0) {        // Forward direction        digitalWrite(DIR_PIN_A, HIGH);        digitalWrite(DIR_PIN_B, LOW);    } else {        // Reverse direction        digitalWrite(DIR_PIN_A, LOW);        digitalWrite(DIR_PIN_B, HIGH);    }        analogWrite(MOTOR_PWM_PIN, pwmValue);}

Testing Before Integration

Before running the full PID controller:

• Test servo/motor with fixed angles/speeds
• Verify direction matches expected behavior
• Identify mechanical limits and dead zones
• Check for smooth motion without jerking