PX4-Autopilot/src/modules/mc_rate_control/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>
#include <px4_platform_common/events.h>

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

MulticopterRateControl::MulticopterRateControl(bool vtol) :
	ModuleParams(nullptr),
	WorkItem(MODULE_NAME, px4::wq_configurations::rate_ctrl),
	_actuators_0_pub(vtol ? ORB_ID(actuator_controls_virtual_mc) : ORB_ID(actuator_controls_0)),
	_loop_perf(perf_alloc(PC_ELAPSED, MODULE_NAME": cycle"))
{
	_vehicle_status.vehicle_type = vehicle_status_s::VEHICLE_TYPE_ROTARY_WING;

	parameters_updated();
	_controller_status_pub.advertise();
}

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.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::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)) {

		// grab corresponding vehicle_angular_acceleration immediately after vehicle_angular_velocity copy
		vehicle_angular_acceleration_s v_angular_acceleration{};
		_vehicle_angular_acceleration_sub.copy(&v_angular_acceleration);

		const hrt_abstime now = angular_velocity.timestamp_sample;

		// Guard against too small (< 0.125ms) and too large (> 20ms) dt's.
		const float dt = math::constrain(((now - _last_run) * 1e-6f), 0.000125f, 0.02f);
		_last_run = now;

		const Vector3f angular_accel{v_angular_acceleration.xyz};
		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_sub.update(&_vehicle_status);

		if (_landing_gear_sub.updated()) {
			landing_gear_s landing_gear;

			if (_landing_gear_sub.copy(&landing_gear)) {
				if (landing_gear.landing_gear != landing_gear_s::GEAR_KEEP) {
					if (landing_gear.landing_gear == landing_gear_s::GEAR_UP && (_landed || _maybe_landed)) {
						mavlink_log_critical(&_mavlink_log_pub, "Landed, unable to retract landing gear\t");
						events::send(events::ID("mc_rate_control_not_retract_landing_gear_landed"),
						{events::Log::Error, events::LogInternal::Info},
						"Landed, unable to retract landing gear");

					} else {
						_landing_gear = landing_gear.landing_gear;
					}
				}
			}
		}

		if (_v_control_mode.flag_control_manual_enabled && !_v_control_mode.flag_control_attitude_enabled) {
			// generate the rate setpoint from sticks
			manual_control_setpoint_s manual_control_setpoint;

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

				_rates_sp = man_rate_sp.emult(_acro_rate_max);
				_thrust_sp = math::constrain(manual_control_setpoint.z, 0.0f, 1.0f);

				// 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) = PX4_ISFINITE(v_rates_sp.roll)  ? v_rates_sp.roll  : rates(0);
				_rates_sp(1) = PX4_ISFINITE(v_rates_sp.pitch) ? v_rates_sp.pitch : rates(1);
				_rates_sp(2) = PX4_ISFINITE(v_rates_sp.yaw)   ? v_rates_sp.yaw   : rates(2);
				_thrust_sp = -v_rates_sp.thrust_body[2];
			}
		}

		// 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 control allocation feedback
			control_allocator_status_s control_allocator_status;

			if (_control_allocator_status_sub.update(&control_allocator_status)) {
				Vector<bool, 3> saturation_positive;
				Vector<bool, 3> saturation_negative;

				if (!control_allocator_status.torque_setpoint_achieved) {
					for (size_t i = 0; i < 3; i++) {
						if (control_allocator_status.unallocated_torque[i] > FLT_EPSILON) {
							saturation_positive(i) = true;

						} else if (control_allocator_status.unallocated_torque[i] < -FLT_EPSILON) {
							saturation_negative(i) = true;
						}
					}
				}

				// TODO: send the unallocated value directly for better anti-windup
				_rate_control.setSaturationStatus(saturation_positive, saturation_negative);
			}

			// run rate controller
			const Vector3f att_control = _rate_control.update(rates, _rates_sp, angular_accel, 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] = _landing_gear;
			actuators.timestamp_sample = angular_velocity.timestamp_sample;

			publishTorqueSetpoint(att_control, angular_velocity.timestamp_sample);
			publishThrustSetpoint(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.connected && battery_status.scale > 0.f) {
						_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();
			_actuators_0_pub.publish(actuators);

			updateActuatorControlsStatus(actuators, dt);

		} 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();
				_actuators_0_pub.publish(actuators);
			}
		}
	}

	perf_end(_loop_perf);
}

void MulticopterRateControl::publishTorqueSetpoint(const Vector3f &torque_sp, const hrt_abstime &timestamp_sample)
{
	vehicle_torque_setpoint_s v_torque_sp = {};
	v_torque_sp.timestamp = hrt_absolute_time();
	v_torque_sp.timestamp_sample = timestamp_sample;
	v_torque_sp.xyz[0] = (PX4_ISFINITE(torque_sp(0))) ? torque_sp(0) : 0.0f;
	v_torque_sp.xyz[1] = (PX4_ISFINITE(torque_sp(1))) ? torque_sp(1) : 0.0f;
	v_torque_sp.xyz[2] = (PX4_ISFINITE(torque_sp(2))) ? torque_sp(2) : 0.0f;

	_vehicle_torque_setpoint_pub.publish(v_torque_sp);
}

void MulticopterRateControl::publishThrustSetpoint(const hrt_abstime &timestamp_sample)
{
	vehicle_thrust_setpoint_s v_thrust_sp = {};
	v_thrust_sp.timestamp = hrt_absolute_time();
	v_thrust_sp.timestamp_sample = timestamp_sample;
	v_thrust_sp.xyz[0] = 0.0f;
	v_thrust_sp.xyz[1] = 0.0f;
	v_thrust_sp.xyz[2] = PX4_ISFINITE(_thrust_sp) ? -_thrust_sp : 0.0f; // Z is Down

	_vehicle_thrust_setpoint_pub.publish(v_thrust_sp);
}

void MulticopterRateControl::updateActuatorControlsStatus(const actuator_controls_s &actuators, float dt)
{
	for (int i = 0; i < 4; i++) {
		_control_energy[i] += actuators.control[i] * actuators.control[i] * dt;
	}

	_energy_integration_time += dt;

	if (_energy_integration_time > 500e-3f) {

		actuator_controls_status_s status;
		status.timestamp = actuators.timestamp;

		for (int i = 0; i < 4; i++) {
			status.control_power[i] = _control_energy[i] / _energy_integration_time;
			_control_energy[i] = 0.f;
		}

		_actuator_controls_status_0_pub.publish(status);
		_energy_integration_time = 0.f;
	}
}

int MulticopterRateControl::task_spawn(int argc, char *argv[])
{
	bool vtol = false;

	if (argc > 1) {
		if (strcmp(argv[1], "vtol") == 0) {
			vtol = true;
		}
	}

	MulticopterRateControl *instance = new MulticopterRateControl(vtol);

	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::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("mc_rate_control", "controller");
	PRINT_MODULE_USAGE_COMMAND("start");
	PRINT_MODULE_USAGE_ARG("vtol", "VTOL mode", true);
	PRINT_MODULE_USAGE_DEFAULT_COMMANDS();

	return 0;
}

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