153 lines
4.5 KiB
C++
153 lines
4.5 KiB
C++
#include <cstdio>
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#include "pico/stdlib.h"
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#include "motor2040.hpp"
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#include "button.hpp"
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#include "pid.hpp"
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/*
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An example of how to move a motor smoothly between random positions,
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with the help of it's attached encoder and PID control.
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Press "Boot" to exit the program.
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*/
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using namespace motor;
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using namespace encoder;
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// The pins of the motor being profiled
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const pin_pair MOTOR_PINS = motor2040::MOTOR_A;
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// The pins of the encoder attached to the profiled motor
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const pin_pair ENCODER_PINS = motor2040::ENCODER_A;
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// The gear ratio of the motor
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constexpr float GEAR_RATIO = 50.0f;
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// The counts per revolution of the motor's output shaft
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constexpr float COUNTS_PER_REV = MMME_CPR * GEAR_RATIO;
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// The direction to spin the motor in. NORMAL_DIR (0), REVERSED_DIR (1)
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const Direction DIRECTION = NORMAL_DIR;
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// The scaling to apply to the motor's speed to match its real-world speed
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constexpr float SPEED_SCALE = 5.4f;
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// How many times to update the motor per second
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const uint UPDATES = 100;
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constexpr float UPDATE_RATE = 1.0f / (float)UPDATES;
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// The time to travel between each random value
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constexpr float TIME_FOR_EACH_MOVE = 1.0f;
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const uint UPDATES_PER_MOVE = TIME_FOR_EACH_MOVE * UPDATES;
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// How many of the updates should be printed (i.e. 2 would be every other update)
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const uint PRINT_DIVIDER = 4;
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// Multipliers for the different printed values, so they appear nicely on the Thonny plotter
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constexpr float SPD_PRINT_SCALE = 20.0f; // Driving Speed multipler
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// How far from zero to move the motor, in degrees
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constexpr float POSITION_EXTENT = 180.0f;
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// The interpolating mode between setpoints. STEP (0), LINEAR (1), COSINE (2)
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const uint INTERP_MODE = 2;
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// PID values
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constexpr float POS_KP = 0.14f; // Position proportional (P) gain
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constexpr float POS_KI = 0.0f; // Position integral (I) gain
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constexpr float POS_KD = 0.002f; // Position derivative (D) gain
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// Create a motor and set its direction and speed scale
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Motor m = Motor(MOTOR_PINS, DIRECTION, SPEED_SCALE);
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// Create an encoder and set its direction and counts per rev, using PIO 0 and State Machine 0
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Encoder enc = Encoder(pio0, 0, ENCODER_PINS, PIN_UNUSED, DIRECTION, COUNTS_PER_REV, true);
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// Create the user button
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Button user_sw(motor2040::USER_SW);
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// Create PID object for position control
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PID pos_pid = PID(POS_KP, POS_KI, POS_KD, UPDATE_RATE);
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int main() {
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stdio_init_all();
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// Initialise the motor and encoder
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m.init();
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enc.init();
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// Enable the motor
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m.enable();
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uint update = 0;
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uint print_count = 0;
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// Set the initial value and create a random end value between the extents
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float start_value = 0.0f;
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float end_value = (((float)rand() / (float)RAND_MAX) * (POSITION_EXTENT * 2.0f)) - POSITION_EXTENT;
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// Continually move the motor until the user button is pressed
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while(!user_sw.raw()) {
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// Capture the state of the encoder
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Encoder::Capture capture = enc.capture();
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// Calculate how far along this movement to be
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float percent_along = (float)update / (float)UPDATES_PER_MOVE;
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switch(INTERP_MODE) {
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case 0:
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// Move the motor instantly to the end value
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pos_pid.setpoint = end_value;
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break;
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case 2:
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// Move the motor between values using cosine
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pos_pid.setpoint = (((-cosf(percent_along * (float)M_PI) + 1.0) / 2.0) * (end_value - start_value)) + start_value;
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break;
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case 1:
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default:
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// Move the motor linearly between values
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pos_pid.setpoint = (percent_along * (end_value - start_value)) + start_value;
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}
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// Calculate the velocity to move the motor closer to the position setpoint
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float vel = pos_pid.calculate(capture.degrees(), capture.degrees_per_second());
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// Set the new motor driving speed
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m.speed(vel);
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// Print out the current motor values and their setpoints, but only on every multiple
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if(print_count == 0) {
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printf("Pos = %f, ", capture.degrees());
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printf("Pos SP = %f, ", pos_pid.setpoint);
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printf("Speed = %f\n", m.speed() * SPD_PRINT_SCALE);
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}
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// Increment the print count, and wrap it
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print_count = (print_count + 1) % PRINT_DIVIDER;
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update++; // Move along in time
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// Have we reached the end of this movement?
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if(update >= UPDATES_PER_MOVE) {
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update = 0; // Reset the counter
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// Set the start as the last end and create a new random end value
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start_value = end_value;
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end_value = (((float)rand() / (float)RAND_MAX) * (POSITION_EXTENT * 2.0f)) - POSITION_EXTENT;
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}
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sleep_ms(UPDATE_RATE * 1000.0f);
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}
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// Disable the motor
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m.disable();
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}
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