smartknob/firmware/src/motor_task.cpp
2022-10-04 22:21:51 -07:00

449 lines
16 KiB
C++

#include <SimpleFOC.h>
#include "motor_task.h"
#if SENSOR_MT6701
#include "mt6701_sensor.h"
#endif
#if SENSOR_TLV
#include "tlv_sensor.h"
#endif
#include "util.h"
// ####
// Hardware-specific motor calibration constants.
// Run calibration once at startup, then update these constants with the calibration results.
static const float ZERO_ELECTRICAL_OFFSET = 2.77;
static const Direction FOC_DIRECTION = Direction::CW;
static const int MOTOR_POLE_PAIRS = 7;
// ####
static const float DEAD_ZONE_DETENT_PERCENT = 0.2;
static const float DEAD_ZONE_RAD = 1 * _PI / 180;
static const float IDLE_VELOCITY_EWMA_ALPHA = 0.001;
static const float IDLE_VELOCITY_RAD_PER_SEC = 0.05;
static const uint32_t IDLE_CORRECTION_DELAY_MILLIS = 500;
static const float IDLE_CORRECTION_MAX_ANGLE_RAD = 5 * PI / 180;
static const float IDLE_CORRECTION_RATE_ALPHA = 0.0005;
MotorTask::MotorTask(const uint8_t task_core) : Task("Motor", 2048, 1, task_core) {
queue_ = xQueueCreate(5, sizeof(Command));
assert(queue_ != NULL);
}
MotorTask::~MotorTask() {}
#if SENSOR_TLV
TlvSensor encoder = TlvSensor();
#elif SENSOR_MT6701
MT6701Sensor encoder = MT6701Sensor();
#endif
Commander command = Commander(Serial);
void MotorTask::run() {
driver.voltage_power_supply = 5;
driver.init();
#if SENSOR_TLV
encoder.init(Wire, false);
#endif
#if SENSOR_MT6701
encoder.init();
#endif
motor.linkDriver(&driver);
motor.controller = MotionControlType::torque;
motor.voltage_limit = 5;
motor.velocity_limit = 10000;
motor.linkSensor(&encoder);
// Not actually using the velocity loop built into SimpleFOC; but I'm using those PID variables
// to run PID for torque (and SimpleFOC studio supports updating them easily over serial for tuning)
motor.PID_velocity.P = 4;
motor.PID_velocity.I = 0;
motor.PID_velocity.D = 0.04;
motor.PID_velocity.output_ramp = 10000;
motor.PID_velocity.limit = 10;
motor.init();
encoder.update();
delay(10);
motor.pole_pairs = MOTOR_POLE_PAIRS;
motor.initFOC(ZERO_ELECTRICAL_OFFSET, FOC_DIRECTION);
bool calibrate = false;
Serial.println("Press Y to run calibration");
uint32_t t = millis();
while (millis() - t < 3000) {
if (Serial.read() == 'Y') {
calibrate = true;
break;
}
delay(10);
}
if (calibrate) {
this->calibrate();
}
Serial.println(motor.zero_electric_angle);
motor.monitor_downsample = 0; // disable monitor at first - optional
// disableCore0WDT();
float current_detent_center = motor.shaft_angle;
KnobConfig config = {
.num_positions = 2,
.position = 0,
.position_width_radians = 60 * _PI / 180,
.detent_strength_unit = 0,
};
float idle_check_velocity_ewma = 0;
uint32_t last_idle_start = 0;
uint32_t last_publish = 0;
while (1) {
motor.loopFOC();
// Check queue for pending requests from other tasks
Command command;
if (xQueueReceive(queue_, &command, 0) == pdTRUE) {
switch (command.command_type) {
case CommandType::CONFIG: {
// Change haptic input mode
config = command.data.config;
Serial.println("Got new config");
current_detent_center = motor.shaft_angle;
#if SK_INVERT_ROTATION
current_detent_center = -motor.shaft_angle;
#endif
// Update derivative factor of torque controller based on detent width.
// If the D factor is large on coarse detents, the motor ends up making noise because the P&D factors amplify the noise from the sensor.
// This is a piecewise linear function so that fine detents (small width) get a higher D factor and coarse detents get a small D factor.
// Fine detents need a nonzero D factor to artificially create "clicks" each time a new value is reached (the P factor is small
// for fine detents due to the smaller angular errors, and the existing P factor doesn't work well for very small angle changes (easy to
// get runaway due to sensor noise & lag)).
// TODO: consider eliminating this D factor entirely and just "play" a hardcoded haptic "click" (e.g. a quick burst of torque in each
// direction) whenever the position changes when the detent width is too small for the P factor to work well.
const float derivative_lower_strength = config.detent_strength_unit * 0.08;
const float derivative_upper_strength = config.detent_strength_unit * 0.02;
const float derivative_position_width_lower = radians(3);
const float derivative_position_width_upper = radians(8);
const float raw = derivative_lower_strength + (derivative_upper_strength - derivative_lower_strength)/(derivative_position_width_upper - derivative_position_width_lower)*(config.position_width_radians - derivative_position_width_lower);
motor.PID_velocity.D = CLAMP(
raw,
min(derivative_lower_strength, derivative_upper_strength),
max(derivative_lower_strength, derivative_upper_strength)
);
break;
}
case CommandType::HAPTIC: {
// Play a hardcoded haptic "click"
float strength = command.data.haptic.press ? 5 : 1.5;
motor.move(strength);
for (uint8_t i = 0; i < 3; i++) {
motor.loopFOC();
delay(1);
}
motor.move(-strength);
for (uint8_t i = 0; i < 3; i++) {
motor.loopFOC();
delay(1);
}
motor.move(0);
motor.loopFOC();
break;
}
}
}
// If we are not moving and we're close to the center (but not exactly there), slowly adjust the centerpoint to match the current position
idle_check_velocity_ewma = motor.shaft_velocity * IDLE_VELOCITY_EWMA_ALPHA + idle_check_velocity_ewma * (1 - IDLE_VELOCITY_EWMA_ALPHA);
if (fabsf(idle_check_velocity_ewma) > IDLE_VELOCITY_RAD_PER_SEC) {
last_idle_start = 0;
} else {
if (last_idle_start == 0) {
last_idle_start = millis();
}
}
if (last_idle_start > 0 && millis() - last_idle_start > IDLE_CORRECTION_DELAY_MILLIS && fabsf(motor.shaft_angle - current_detent_center) < IDLE_CORRECTION_MAX_ANGLE_RAD) {
current_detent_center = motor.shaft_angle * IDLE_CORRECTION_RATE_ALPHA + current_detent_center * (1 - IDLE_CORRECTION_RATE_ALPHA);
}
// Check where we are relative to the current nearest detent; update our position if we've moved far enough to snap to another detent
float angle_to_detent_center = motor.shaft_angle - current_detent_center;
#if SK_INVERT_ROTATION
angle_to_detent_center = -motor.shaft_angle - current_detent_center;
#endif
if (angle_to_detent_center > config.position_width_radians * config.snap_point && (config.num_positions <= 0 || config.position > 0)) {
current_detent_center += config.position_width_radians;
angle_to_detent_center -= config.position_width_radians;
config.position--;
} else if (angle_to_detent_center < -config.position_width_radians * config.snap_point && (config.num_positions <= 0 || config.position < config.num_positions - 1)) {
current_detent_center -= config.position_width_radians;
angle_to_detent_center += config.position_width_radians;
config.position++;
}
float dead_zone_adjustment = CLAMP(
angle_to_detent_center,
fmaxf(-config.position_width_radians*DEAD_ZONE_DETENT_PERCENT, -DEAD_ZONE_RAD),
fminf(config.position_width_radians*DEAD_ZONE_DETENT_PERCENT, DEAD_ZONE_RAD));
bool out_of_bounds = config.num_positions > 0 && ((angle_to_detent_center > 0 && config.position == 0) || (angle_to_detent_center < 0 && config.position == config.num_positions - 1));
motor.PID_velocity.limit = 10; //out_of_bounds ? 10 : 3;
motor.PID_velocity.P = out_of_bounds ? config.endstop_strength_unit * 4 : config.detent_strength_unit * 4;
// Apply motor torque based on our angle to the nearest detent (detent strength, etc is handled by the PID_velocity parameters)
if (fabsf(motor.shaft_velocity) > 60) {
// Don't apply torque if velocity is too high (helps avoid positive feedback loop/runaway)
motor.move(0);
} else {
float torque = motor.PID_velocity(-angle_to_detent_center + dead_zone_adjustment);
#if SK_INVERT_ROTATION
torque = -torque;
#endif
motor.move(torque);
}
// Publish current status to other registered tasks periodically
if (millis() - last_publish > 10) {
publish({
.current_position = config.position,
.sub_position_unit = -angle_to_detent_center / config.position_width_radians,
.config = config,
});
last_publish = millis();
}
motor.monitor();
delay(1);
}
}
void MotorTask::setConfig(const KnobConfig& config) {
Command command = {
.command_type = CommandType::CONFIG,
.data = {
.config = config,
}
};
xQueueSend(queue_, &command, portMAX_DELAY);
}
void MotorTask::playHaptic(bool press) {
Command command = {
.command_type = CommandType::HAPTIC,
.data = {
.haptic = {
.press = press,
},
}
};
xQueueSend(queue_, &command, portMAX_DELAY);
}
void MotorTask::addListener(QueueHandle_t queue) {
listeners_.push_back(queue);
}
void MotorTask::publish(const KnobState& state) {
for (auto listener : listeners_) {
xQueueOverwrite(listener, &state);
}
}
void MotorTask::calibrate() {
// SimpleFOC is supposed to be able to determine this automatically (if you omit params to initFOC), but
// it seems to have a bug (or I've misconfigured it) that gets both the offset and direction very wrong!
// So this value is based on experimentation.
// TODO: dig into SimpleFOC calibration and find/fix the issue
Serial.println("\n\n\nStarting calibration, please do not touch to motor until complete!");
motor.controller = MotionControlType::angle_openloop;
motor.pole_pairs = 1;
motor.initFOC(0, Direction::CW);
float a = 0;
// #### Determine direction motor rotates relative to angle sensor
for (uint8_t i = 0; i < 200; i++) {
encoder.update();
motor.move(a);
delay(1);
}
float start_sensor = encoder.getAngle();
for (; a < 3 * _2PI; a += 0.01) {
encoder.update();
motor.move(a);
delay(1);
}
for (uint8_t i = 0; i < 200; i++) {
encoder.update();
delay(1);
}
float end_sensor = encoder.getAngle();
motor.voltage_limit = 0;
motor.move(a);
Serial.println();
// TODO: check for no motor movement!
Serial.print("Sensor measures positive for positive motor rotation: ");
if (end_sensor > start_sensor) {
Serial.println("YES, Direction=CW");
motor.initFOC(0, Direction::CW);
} else {
Serial.println("NO, Direction=CCW");
motor.initFOC(0, Direction::CCW);
}
// #### Determine pole-pairs
// Rotate 20 electrical revolutions and measure mechanical angle traveled, to calculate pole-pairs
uint8_t electrical_revolutions = 20;
Serial.printf("Going to measure %d electrical revolutions...\n", electrical_revolutions);
motor.voltage_limit = 5;
motor.move(a);
Serial.println("Going to electrical zero...");
float destination = a + _2PI;
for (; a < destination; a += 0.03) {
encoder.update();
motor.move(a);
delay(1);
}
Serial.println("pause..."); // Let momentum settle...
for (uint16_t i = 0; i < 1000; i++) {
encoder.update();
delay(1);
}
Serial.println("Measuring...");
start_sensor = motor.sensor_direction * encoder.getAngle();
destination = a + electrical_revolutions * _2PI;
for (; a < destination; a += 0.03) {
encoder.update();
motor.move(a);
delay(1);
}
for (uint16_t i = 0; i < 1000; i++) {
encoder.update();
motor.move(a);
delay(1);
}
end_sensor = motor.sensor_direction * encoder.getAngle();
motor.voltage_limit = 0;
motor.move(a);
if (fabsf(motor.shaft_angle - motor.target) > 1 * PI / 180) {
Serial.println("ERROR: motor did not reach target!");
while(1) {}
}
float electrical_per_mechanical = electrical_revolutions * _2PI / (end_sensor - start_sensor);
Serial.print("Electrical angle / mechanical angle (i.e. pole pairs) = ");
Serial.println(electrical_per_mechanical);
int measured_pole_pairs = (int)round(electrical_per_mechanical);
Serial.printf("Pole pairs set to %d\n", measured_pole_pairs);
delay(1000);
// #### Determine mechanical offset to electrical zero
// Measure mechanical angle at every electrical zero for several revolutions
motor.voltage_limit = 5;
motor.move(a);
float offset_x = 0;
float offset_y = 0;
float destination1 = (floor(a / _2PI) + measured_pole_pairs / 2.) * _2PI;
float destination2 = (floor(a / _2PI)) * _2PI;
for (; a < destination1; a += 0.4) {
motor.move(a);
delay(100);
for (uint8_t i = 0; i < 100; i++) {
encoder.update();
delay(1);
}
float real_electrical_angle = _normalizeAngle(a);
float measured_electrical_angle = _normalizeAngle( (float)(motor.sensor_direction * measured_pole_pairs) * encoder.getMechanicalAngle() - 0);
float offset_angle = measured_electrical_angle - real_electrical_angle;
offset_x += cosf(offset_angle);
offset_y += sinf(offset_angle);
Serial.print(degrees(real_electrical_angle));
Serial.print(", ");
Serial.print(degrees(measured_electrical_angle));
Serial.print(", ");
Serial.println(degrees(_normalizeAngle(offset_angle)));
}
for (; a > destination2; a -= 0.4) {
motor.move(a);
delay(100);
for (uint8_t i = 0; i < 100; i++) {
encoder.update();
delay(1);
}
float real_electrical_angle = _normalizeAngle(a);
float measured_electrical_angle = _normalizeAngle( (float)(motor.sensor_direction * measured_pole_pairs) * encoder.getMechanicalAngle() - 0);
float offset_angle = measured_electrical_angle - real_electrical_angle;
offset_x += cosf(offset_angle);
offset_y += sinf(offset_angle);
Serial.print(degrees(real_electrical_angle));
Serial.print(", ");
Serial.print(degrees(measured_electrical_angle));
Serial.print(", ");
Serial.println(degrees(_normalizeAngle(offset_angle)));
}
motor.voltage_limit = 0;
motor.move(a);
float avg_offset_angle = atan2f(offset_y, offset_x);
// #### Apply settings
// TODO: save to non-volatile storage
motor.pole_pairs = measured_pole_pairs;
motor.zero_electric_angle = avg_offset_angle + _3PI_2;
motor.voltage_limit = 5;
motor.controller = MotionControlType::torque;
Serial.print("\n\nRESULTS:\n Update these constants at the top of " __FILE__ "\n ZERO_ELECTRICAL_OFFSET: ");
Serial.println(motor.zero_electric_angle);
Serial.print(" FOC_DIRECTION: ");
if (motor.sensor_direction == Direction::CW) {
Serial.println("Direction::CW");
} else {
Serial.println("Direction::CCW");
}
Serial.printf(" MOTOR_POLE_PAIRS: %d\n", motor.pole_pairs);
delay(2000);
}