smartknob/firmware/src/motor_task.cpp

#include <SimpleFOC.h>
#include <sensors/MagneticSensorI2C.h>

#include "motor_task.h"
#include "mt6701_sensor.h"
#include "tlv_sensor.h"
#include "util.h"

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", 1200, 1, task_core) {
    queue_ = xQueueCreate(5, sizeof(Command));
    assert(queue_ != NULL);
}

MotorTask::~MotorTask() {}


// BLDC motor & driver instance
BLDCMotor motor = BLDCMotor(1);
BLDCDriver6PWM driver = BLDCDriver6PWM(PIN_UH, PIN_UL, PIN_VH, PIN_VL, PIN_WH, PIN_WL);

#if SENSOR_TLV
    TlvSensor encoder = TlvSensor();
#elif SENSOR_MT6701
    MT6701Sensor encoder = MT6701Sensor();
#endif
// MagneticSensorI2C tlv = MagneticSensorI2C(AS5600_I2C);

Commander command = Commander(Serial);


void doMotor(char* cmd) { command.motor(&motor, cmd); }

void MotorTask::run() {
    // Hardware-specific configuration:
    // TODO: make this easier to configure
    // Tune zero offset to the specific hardware (motor + mounted magnetic sensor).
    // 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
    // float zero_electric_offset = -0.6; // original proto
    //float zero_electric_offset = 0.4; // handheld 1
    // float zero_electric_offset = -0.8; // handheld 2
    // float zero_electric_offset = 2.93; //0.15; // 17mm test
    // float zero_electric_offset = 0.66; // 15mm handheld
    float zero_electric_offset = 7.34;
    Direction foc_direction = Direction::CW;
    motor.pole_pairs = 7;

    driver.voltage_power_supply = 5;
    driver.init();

    #if SENSOR_TLV
    encoder.init(Wire, false);
    #endif

    #if SENSOR_MT6701
    encoder.init();
    // motor.LPF_angle = LowPassFilter(0.05);
    #endif
    // motor.LPF_current_q = {0.01};

    motor.linkDriver(&driver);

    motor.controller = MotionControlType::torque;
    motor.voltage_limit = 5;
    motor.velocity_limit = 10000;
    motor.linkSensor(&encoder);

    // Not actually using the velocity loop; but I'm using those PID variables
    // because 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.useMonitoring(Serial);

    motor.init();

    encoder.update();
    delay(10);

    motor.initFOC(zero_electric_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) {
        motor.controller = MotionControlType::angle_openloop;
        motor.pole_pairs = 1;
        motor.initFOC(0, Direction::CW);


        float a = 0;

        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("Did motor turn counterclockwise? Press Y to continue, otherwise change motor wiring and restart");
        // while (Serial.read() != 'Y') {
        //     delay(10);
        // }

        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);
        }

        // Rotate many 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...");
        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);



        // 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
        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  zero electric angle: ");
        Serial.println(motor.zero_electric_angle);
        Serial.print("  direction: ");
        if (motor.sensor_direction == Direction::CW) {
            Serial.println("CW");
        } else {
            Serial.println("CCW");
        }
        Serial.printf("  pole pairs: %d\n", motor.pole_pairs);
        delay(2000);
    }

    Serial.println(motor.zero_electric_angle);

    command.add('M', &doMotor, "foo");
    // command.add('D', &doDetents, "Detents");
    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_debug = 0;

    uint32_t last_publish = 0;

    while (1) {
        motor.loopFOC();

        Command command;
        if (xQueueReceive(queue_, &command, 0) == pdTRUE) {
            switch (command.command_type) {
                case CommandType::CONFIG: {
                    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: {
                    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;
                }
            }
        }

        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 we are not moving and we're close to the center (but not exactly there), slowly adjust the centerpoint to match the current position
        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);
            // if (millis() - last_debug > 100) {
            //     last_debug = millis();
            //     Serial.print("Moving detent center. ");
            //     Serial.print(current_detent_center);
            //     Serial.print(" ");
            //     Serial.println(motor.shaft_angle);
            // }
        }

        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;



        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);
        }

        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();
        // command.run();

        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);
    }
}