PX4-Autopilot/src/drivers/uavcan/actuators/esc.cpp

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/**
 * @file esc.cpp
 *
 * @author Pavel Kirienko <pavel.kirienko@gmail.com>
 */

#include "esc.hpp"
#include <systemlib/err.h>
#include <drivers/drv_hrt.h>

#define MOTOR_BIT(x) (1<<(x))

using namespace time_literals;

UavcanEscController::UavcanEscController(uavcan::INode &node) :
	_node(node),
	_uavcan_pub_raw_cmd(node),
	_uavcan_sub_status(node),
	_orb_timer(node)
{
	_uavcan_pub_raw_cmd.setPriority(UAVCAN_COMMAND_TRANSFER_PRIORITY);
}

UavcanEscController::~UavcanEscController()
{
	perf_free(_perfcnt_invalid_input);
	perf_free(_perfcnt_scaling_error);
}

int
UavcanEscController::init()
{
	// ESC status subscription
	int res = _uavcan_sub_status.start(StatusCbBinder(this, &UavcanEscController::esc_status_sub_cb));

	if (res < 0) {
		PX4_ERR("ESC status sub failed %i", res);
		return res;
	}

	// ESC status will be relayed from UAVCAN bus into ORB at this rate
	_orb_timer.setCallback(TimerCbBinder(this, &UavcanEscController::orb_pub_timer_cb));
	_orb_timer.startPeriodic(uavcan::MonotonicDuration::fromMSec(1000 / ESC_STATUS_UPDATE_RATE_HZ));

	return res;
}

void
UavcanEscController::update_outputs(float *outputs, unsigned num_outputs)
{
	if ((outputs == nullptr) ||
	    (num_outputs > uavcan::equipment::esc::RawCommand::FieldTypes::cmd::MaxSize) ||
	    (num_outputs > esc_status_s::CONNECTED_ESC_MAX)) {

		perf_count(_perfcnt_invalid_input);
		return;
	}

	/*
	 * Rate limiting - we don't want to congest the bus
	 */
	const auto timestamp = _node.getMonotonicTime();

	if ((timestamp - _prev_cmd_pub).toUSec() < (1000000 / MAX_RATE_HZ)) {
		return;
	}

	_prev_cmd_pub = timestamp;

	/*
	 * Fill the command message
	 * If unarmed, we publish an empty message anyway
	 */
	uavcan::equipment::esc::RawCommand msg;

	actuator_outputs_s actuator_outputs{};
	actuator_outputs.noutputs = num_outputs;

	static const int cmd_max = uavcan::equipment::esc::RawCommand::FieldTypes::cmd::RawValueType::max();
	const float cmd_min = _run_at_idle_throttle_when_armed ? 1.0F : 0.0F;

	for (unsigned i = 0; i < num_outputs; i++) {
		if (_armed_mask & MOTOR_BIT(i)) {
			float scaled = (outputs[i] + 1.0F) * 0.5F * cmd_max;

			// trim negative values back to minimum
			if (scaled < cmd_min) {
				scaled = cmd_min;
				perf_count(_perfcnt_scaling_error);
			}

			if (scaled > cmd_max) {
				scaled = cmd_max;
				perf_count(_perfcnt_scaling_error);
			}

			msg.cmd.push_back(static_cast<int>(scaled));

			_esc_status.esc[i].esc_setpoint_raw = abs(static_cast<int>(scaled));
			actuator_outputs.output[i] = scaled;

		} else {
			msg.cmd.push_back(static_cast<unsigned>(0));
			actuator_outputs.output[i] = 0.0f;
		}
	}

	/*
	 * Remove channels that are always zero.
	 * The objective of this optimization is to avoid broadcasting multi-frame transfers when a single frame
	 * transfer would be enough. This is a valid optimization as the UAVCAN specification implies that all
	 * non-specified ESC setpoints should be considered zero.
	 * The positive outcome is a (marginally) lower bus traffic and lower CPU load.
	 *
	 * From the standpoint of the PX4 architecture, however, this is a hack. It should be investigated why
	 * the mixer returns more outputs than are actually used.
	 */
	for (int index = int(msg.cmd.size()) - 1; index >= _max_number_of_nonzero_outputs; index--) {
		if (msg.cmd[index] != 0) {
			_max_number_of_nonzero_outputs = index + 1;
			break;
		}
	}

	msg.cmd.resize(_max_number_of_nonzero_outputs);

	/*
	 * Publish the command message to the bus
	 * Note that for a quadrotor it takes one CAN frame
	 */
	_uavcan_pub_raw_cmd.broadcast(msg);

	// Publish actuator outputs
	actuator_outputs.timestamp = hrt_absolute_time();
	_actuator_outputs_pub.publish(actuator_outputs);
}

void
UavcanEscController::arm_all_escs(bool arm)
{
	if (arm) {
		_armed_mask = -1;

	} else {
		_armed_mask = 0;
	}
}

void
UavcanEscController::arm_single_esc(int num, bool arm)
{
	if (arm) {
		_armed_mask = MOTOR_BIT(num);

	} else {
		_armed_mask = 0;
	}
}

void
UavcanEscController::esc_status_sub_cb(const uavcan::ReceivedDataStructure<uavcan::equipment::esc::Status> &msg)
{
	if (msg.esc_index < esc_status_s::CONNECTED_ESC_MAX) {
		auto &ref = _esc_status.esc[msg.esc_index];

		ref.esc_address = msg.getSrcNodeID().get();
		ref.timestamp       = hrt_absolute_time();
		ref.esc_voltage     = msg.voltage;
		ref.esc_current     = msg.current;
		ref.esc_temperature = msg.temperature;
		ref.esc_setpoint    = msg.power_rating_pct;
		ref.esc_rpm         = msg.rpm;
		ref.esc_errorcount  = msg.error_count;
	}
}

void
UavcanEscController::orb_pub_timer_cb(const uavcan::TimerEvent &)
{
	_esc_status.timestamp = hrt_absolute_time();
	_esc_status.esc_count = _rotor_count;
	_esc_status.counter += 1;
	_esc_status.esc_connectiontype = esc_status_s::ESC_CONNECTION_TYPE_CAN;
	_esc_status.esc_online_flags = UavcanEscController::check_escs_status();

	_esc_status_pub.publish(_esc_status);
}

uint8_t
UavcanEscController::check_escs_status()
{
	int esc_status_flags = 0;
	const hrt_abstime now = hrt_absolute_time();

	for (int index = 0; index < esc_status_s::CONNECTED_ESC_MAX; index++) {

		if (_esc_status.esc[index].timestamp > 0 && now - _esc_status.esc[index].timestamp < 1200_ms) {
			esc_status_flags |= (1 << index);
		}

	}

	return esc_status_flags;
}