MulticopterRateControl.cpp

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#include "MulticopterRateControl.hpp"

#include <drivers/drv_hrt.h>
#include <circuit_breaker/circuit_breaker.h>
#include <mathlib/math/Limits.hpp>
#include <mathlib/math/Functions.hpp>

using namespace matrix;
using namespace time_literals;
using math::radians;

MulticopterRateControl::MulticopterRateControl() :
    ModuleParams(nullptr),
    WorkItem(MODULE_NAME, px4::wq_configurations::rate_ctrl),
    _loop_perf(perf_alloc(PC_ELAPSED, MODULE_NAME": cycle"))
{
    _vehicle_status.vehicle_type = vehicle_status_s::VEHICLE_TYPE_ROTARY_WING;

    parameters_updated();
}

MulticopterRateControl::~MulticopterRateControl()
{
    perf_free(_loop_perf);
}

bool
MulticopterRateControl::init()
{
    if (!_vehicle_angular_velocity_sub.registerCallback()) {
        PX4_ERR("vehicle_angular_velocity callback registration failed!");
        return false;
    }

    return true;
}

void
MulticopterRateControl::parameters_updated()
{
    // rate control parameters
    // The controller gain K is used to convert the parallel (P + I/s + sD) form
    // to the ideal (K * [1 + 1/sTi + sTd]) form
    const Vector3f rate_k = Vector3f(_param_mc_rollrate_k.get(), _param_mc_pitchrate_k.get(), _param_mc_yawrate_k.get());

    _rate_control.setGains(
        rate_k.emult(Vector3f(_param_mc_rollrate_p.get(), _param_mc_pitchrate_p.get(), _param_mc_yawrate_p.get())),
        rate_k.emult(Vector3f(_param_mc_rollrate_i.get(), _param_mc_pitchrate_i.get(), _param_mc_yawrate_i.get())),
        rate_k.emult(Vector3f(_param_mc_rollrate_d.get(), _param_mc_pitchrate_d.get(), _param_mc_yawrate_d.get())));

    _rate_control.setIntegratorLimit(
        Vector3f(_param_mc_rr_int_lim.get(), _param_mc_pr_int_lim.get(), _param_mc_yr_int_lim.get()));

    _rate_control.setDTermCutoff(_loop_update_rate_hz, _param_mc_dterm_cutoff.get(), false);

    _rate_control.setFeedForwardGain(
        Vector3f(_param_mc_rollrate_ff.get(), _param_mc_pitchrate_ff.get(), _param_mc_yawrate_ff.get()));


    // manual rate control acro mode rate limits
    _acro_rate_max = Vector3f(radians(_param_mc_acro_r_max.get()), radians(_param_mc_acro_p_max.get()),
                  radians(_param_mc_acro_y_max.get()));

    _actuators_0_circuit_breaker_enabled = circuit_breaker_enabled_by_val(_param_cbrk_rate_ctrl.get(), CBRK_RATE_CTRL_KEY);
}

void
MulticopterRateControl::vehicle_status_poll()
{
    /* check if there is new status information */
    if (_vehicle_status_sub.update(&_vehicle_status)) {
        /* set correct uORB ID, depending on if vehicle is VTOL or not */
        if (_actuators_id == nullptr) {
            if (_vehicle_status.is_vtol) {
                _actuators_id = ORB_ID(actuator_controls_virtual_mc);

            } else {
                _actuators_id = ORB_ID(actuator_controls_0);
            }
        }
    }
}

float
MulticopterRateControl::get_landing_gear_state()
{
    // Only switch the landing gear up if we are not landed and if
    // the user switched from gear down to gear up.
    // If the user had the switch in the gear up position and took off ignore it
    // until he toggles the switch to avoid retracting the gear immediately on takeoff.
    if (_landed) {
        _gear_state_initialized = false;
    }

    float landing_gear = landing_gear_s::GEAR_DOWN; // default to down

    if (_manual_control_sp.gear_switch == manual_control_setpoint_s::SWITCH_POS_ON && _gear_state_initialized) {
        landing_gear = landing_gear_s::GEAR_UP;

    } else if (_manual_control_sp.gear_switch == manual_control_setpoint_s::SWITCH_POS_OFF) {
        // Switching the gear off does put it into a safe defined state
        _gear_state_initialized = true;
    }

    return landing_gear;
}

void
MulticopterRateControl::Run()
{
    if (should_exit()) {
        _vehicle_angular_velocity_sub.unregisterCallback();
        exit_and_cleanup();
        return;
    }

    perf_begin(_loop_perf);

    // Check if parameters have changed
    if (_parameter_update_sub.updated()) {
        // clear update
        parameter_update_s param_update;
        _parameter_update_sub.copy(&param_update);

        updateParams();
        parameters_updated();
    }

    /* run controller on gyro changes */
    vehicle_angular_velocity_s angular_velocity;

    if (_vehicle_angular_velocity_sub.update(&angular_velocity)) {
        const hrt_abstime now = hrt_absolute_time();

        // Guard against too small (< 0.2ms) and too large (> 20ms) dt's.
        const float dt = math::constrain(((now - _last_run) / 1e6f), 0.0002f, 0.02f);
        _last_run = now;

        const Vector3f rates{angular_velocity.xyz};

        /* check for updates in other topics */
        _v_control_mode_sub.update(&_v_control_mode);

        if (_vehicle_land_detected_sub.updated()) {
            vehicle_land_detected_s vehicle_land_detected;

            if (_vehicle_land_detected_sub.copy(&vehicle_land_detected)) {
                _landed = vehicle_land_detected.landed;
                _maybe_landed = vehicle_land_detected.maybe_landed;
            }
        }

        vehicle_status_poll();

        const bool manual_control_updated = _manual_control_sp_sub.update(&_manual_control_sp);

        // generate the rate setpoint from sticks?
        bool manual_rate_sp = false;

        if (_v_control_mode.flag_control_manual_enabled &&
            !_v_control_mode.flag_control_altitude_enabled &&
            !_v_control_mode.flag_control_velocity_enabled &&
            !_v_control_mode.flag_control_position_enabled) {

            // landing gear controlled from stick inputs if we are in Manual/Stabilized mode
            //  limit landing gear update rate to 50 Hz
            if (hrt_elapsed_time(&_landing_gear.timestamp) > 20_ms) {
                _landing_gear.landing_gear = get_landing_gear_state();
                _landing_gear.timestamp = hrt_absolute_time();
                _landing_gear_pub.publish(_landing_gear);
            }

            if (!_v_control_mode.flag_control_attitude_enabled) {
                manual_rate_sp = true;
            }

            // Check if we are in rattitude mode and the pilot is within the center threshold on pitch and roll
            //  if true then use published rate setpoint, otherwise generate from manual_control_setpoint (like acro)
            if (_v_control_mode.flag_control_rattitude_enabled) {
                manual_rate_sp =
                    (fabsf(_manual_control_sp.y) > _param_mc_ratt_th.get()) ||
                    (fabsf(_manual_control_sp.x) > _param_mc_ratt_th.get());
            }

        } else {
            _landing_gear_sub.update(&_landing_gear);
        }

        if (manual_rate_sp) {
            if (manual_control_updated) {

                // manual rates control - ACRO mode
                const Vector3f man_rate_sp{
                    math::superexpo(_manual_control_sp.y, _param_mc_acro_expo.get(), _param_mc_acro_supexpo.get()),
                    math::superexpo(-_manual_control_sp.x, _param_mc_acro_expo.get(), _param_mc_acro_supexpo.get()),
                    math::superexpo(_manual_control_sp.r, _param_mc_acro_expo_y.get(), _param_mc_acro_supexpoy.get())};

                _rates_sp = man_rate_sp.emult(_acro_rate_max);
                _thrust_sp = _manual_control_sp.z;

                // publish rate setpoint
                vehicle_rates_setpoint_s v_rates_sp{};
                v_rates_sp.roll = _rates_sp(0);
                v_rates_sp.pitch = _rates_sp(1);
                v_rates_sp.yaw = _rates_sp(2);
                v_rates_sp.thrust_body[0] = 0.0f;
                v_rates_sp.thrust_body[1] = 0.0f;
                v_rates_sp.thrust_body[2] = -_thrust_sp;
                v_rates_sp.timestamp = hrt_absolute_time();

                _v_rates_sp_pub.publish(v_rates_sp);
            }

        } else {
            // use rates setpoint topic
            vehicle_rates_setpoint_s v_rates_sp;

            if (_v_rates_sp_sub.update(&v_rates_sp)) {
                _rates_sp(0) = v_rates_sp.roll;
                _rates_sp(1) = v_rates_sp.pitch;
                _rates_sp(2) = v_rates_sp.yaw;
                _thrust_sp = -v_rates_sp.thrust_body[2];
            }
        }

        // calculate loop update rate while disarmed or at least a few times (updating the filter is expensive)
        if (!_v_control_mode.flag_armed || (now - _task_start) < 3300000) {
            _dt_accumulator += dt;
            ++_loop_counter;

            if (_dt_accumulator > 1.0f) {
                const float loop_update_rate = (float)_loop_counter / _dt_accumulator;
                _loop_update_rate_hz = _loop_update_rate_hz * 0.5f + loop_update_rate * 0.5f;
                _dt_accumulator = 0;
                _loop_counter = 0;
                _rate_control.setDTermCutoff(_loop_update_rate_hz, _param_mc_dterm_cutoff.get(), true);
            }
        }

        // run the rate controller
        if (_v_control_mode.flag_control_rates_enabled && !_actuators_0_circuit_breaker_enabled) {

            // reset integral if disarmed
            if (!_v_control_mode.flag_armed || _vehicle_status.vehicle_type != vehicle_status_s::VEHICLE_TYPE_ROTARY_WING) {
                _rate_control.resetIntegral();
            }

            // update saturation status from mixer feedback
            if (_motor_limits_sub.updated()) {
                multirotor_motor_limits_s motor_limits;

                if (_motor_limits_sub.copy(&motor_limits)) {
                    MultirotorMixer::saturation_status saturation_status;
                    saturation_status.value = motor_limits.saturation_status;

                    _rate_control.setSaturationStatus(saturation_status);
                }
            }

            // run rate controller
            const Vector3f att_control = _rate_control.update(rates, _rates_sp, dt, _maybe_landed || _landed);

            // publish rate controller status
            rate_ctrl_status_s rate_ctrl_status{};
            _rate_control.getRateControlStatus(rate_ctrl_status);
            rate_ctrl_status.timestamp = hrt_absolute_time();
            _controller_status_pub.publish(rate_ctrl_status);

            // publish actuator controls
            actuator_controls_s actuators{};
            actuators.control[actuator_controls_s::INDEX_ROLL] = PX4_ISFINITE(att_control(0)) ? att_control(0) : 0.0f;
            actuators.control[actuator_controls_s::INDEX_PITCH] = PX4_ISFINITE(att_control(1)) ? att_control(1) : 0.0f;
            actuators.control[actuator_controls_s::INDEX_YAW] = PX4_ISFINITE(att_control(2)) ? att_control(2) : 0.0f;
            actuators.control[actuator_controls_s::INDEX_THROTTLE] = PX4_ISFINITE(_thrust_sp) ? _thrust_sp : 0.0f;
            actuators.control[actuator_controls_s::INDEX_LANDING_GEAR] = (float)_landing_gear.landing_gear;
            actuators.timestamp_sample = angular_velocity.timestamp_sample;

            // scale effort by battery status if enabled
            if (_param_mc_bat_scale_en.get()) {
                if (_battery_status_sub.updated()) {
                    battery_status_s battery_status;

                    if (_battery_status_sub.copy(&battery_status)) {
                        _battery_status_scale = battery_status.scale;
                    }
                }

                if (_battery_status_scale > 0.0f) {
                    for (int i = 0; i < 4; i++) {
                        actuators.control[i] *= _battery_status_scale;
                    }
                }
            }

            actuators.timestamp = hrt_absolute_time();
            orb_publish_auto(_actuators_id, &_actuators_0_pub, &actuators, nullptr, ORB_PRIO_DEFAULT);

        } else if (_v_control_mode.flag_control_termination_enabled) {
            if (!_vehicle_status.is_vtol) {
                // publish actuator controls
                actuator_controls_s actuators{};
                actuators.timestamp = hrt_absolute_time();
                orb_publish_auto(_actuators_id, &_actuators_0_pub, &actuators, nullptr, ORB_PRIO_DEFAULT);
            }
        }
    }

    perf_end(_loop_perf);
}

int MulticopterRateControl::task_spawn(int argc, char *argv[])
{
    MulticopterRateControl *instance = new MulticopterRateControl();

    if (instance) {
        _object.store(instance);
        _task_id = task_id_is_work_queue;

        if (instance->init()) {
            return PX4_OK;
        }

    } else {
        PX4_ERR("alloc failed");
    }

    delete instance;
    _object.store(nullptr);
    _task_id = -1;

    return PX4_ERROR;
}

int MulticopterRateControl::print_status()
{
    PX4_INFO("Running");

    perf_print_counter(_loop_perf);

    return 0;
}

int MulticopterRateControl::custom_command(int argc, char *argv[])
{
    return print_usage("unknown command");
}

int MulticopterRateControl::print_usage(const char *reason)
{
    if (reason) {
        PX4_WARN("%s\n", reason);
    }

    PRINT_MODULE_DESCRIPTION(
        R"DESCR_STR(
### Description
This implements the multicopter rate controller. It takes rate setpoints (in acro mode
via `manual_control_setpoint` topic) as inputs and outputs actuator control messages.

The controller has a PID loop for angular rate error.

)DESCR_STR");

    PRINT_MODULE_USAGE_NAME(MODULE_NAME, "controller");
    PRINT_MODULE_USAGE_COMMAND("start");
    PRINT_MODULE_USAGE_DEFAULT_COMMANDS();

    return 0;
}

/**
 * Multicopter rate control app start / stop handling function
 */
extern "C" __EXPORT int mc_rate_control_main(int argc, char *argv[]);

int mc_rate_control_main(int argc, char *argv[])
{
    return MulticopterRateControl::main(argc, argv);
}