rc_update.cpp

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/**
 * @file rc_update.cpp
 *
 * @author Beat Kueng <beat-kueng@gmx.net>
 */

#include "rc_update.h"

#include "parameters.h"

namespace RCUpdate
{

RCUpdate::RCUpdate() :
    ModuleParams(nullptr),
    WorkItem(MODULE_NAME, px4::wq_configurations::hp_default),
    _loop_perf(perf_alloc(PC_ELAPSED, MODULE_NAME)),
    _filter_roll(50.0f, 10.f), /* get replaced by parameter */
    _filter_pitch(50.0f, 10.f),
    _filter_yaw(50.0f, 10.f),
    _filter_throttle(50.0f, 10.f)
{
    initialize_parameter_handles(_parameter_handles);
    rc_parameter_map_poll(true /* forced */);

    parameters_updated();
}

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

bool
RCUpdate::init()
{
    if (!_input_rc_sub.registerCallback()) {
        PX4_ERR("input_rc callback registration failed!");
        return false;
    }

    return true;
}

void
RCUpdate::parameters_updated()
{
    /* read the parameter values into _parameters */
    update_parameters(_parameter_handles, _parameters);

    update_rc_functions();
}

void
RCUpdate::update_rc_functions()
{
    /* update RC function mappings */
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_THROTTLE] = _parameters.rc_map_throttle - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_ROLL] = _parameters.rc_map_roll - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_PITCH] = _parameters.rc_map_pitch - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_YAW] = _parameters.rc_map_yaw - 1;

    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_MODE] = _parameters.rc_map_mode_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_RETURN] = _parameters.rc_map_return_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_RATTITUDE] = _parameters.rc_map_rattitude_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_POSCTL] = _parameters.rc_map_posctl_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_LOITER] = _parameters.rc_map_loiter_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_ACRO] = _parameters.rc_map_acro_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_OFFBOARD] = _parameters.rc_map_offboard_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_KILLSWITCH] = _parameters.rc_map_kill_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_ARMSWITCH] = _parameters.rc_map_arm_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_TRANSITION] = _parameters.rc_map_trans_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_GEAR] = _parameters.rc_map_gear_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_STAB] = _parameters.rc_map_stab_sw - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_MAN] = _parameters.rc_map_man_sw - 1;

    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_FLAPS] = _parameters.rc_map_flaps - 1;

    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_AUX_1] = _parameters.rc_map_aux1 - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_AUX_2] = _parameters.rc_map_aux2 - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_AUX_3] = _parameters.rc_map_aux3 - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_AUX_4] = _parameters.rc_map_aux4 - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_AUX_5] = _parameters.rc_map_aux5 - 1;
    _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_AUX_6] = _parameters.rc_map_aux6 - 1;

    for (int i = 0; i < rc_parameter_map_s::RC_PARAM_MAP_NCHAN; i++) {
        _rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_PARAM_1 + i] = _parameters.rc_map_param[i] - 1;
    }

    /* update the RC low pass filter frequencies */
    _filter_roll.set_cutoff_frequency(_parameters.rc_flt_smp_rate, _parameters.rc_flt_cutoff);
    _filter_pitch.set_cutoff_frequency(_parameters.rc_flt_smp_rate, _parameters.rc_flt_cutoff);
    _filter_yaw.set_cutoff_frequency(_parameters.rc_flt_smp_rate, _parameters.rc_flt_cutoff);
    _filter_throttle.set_cutoff_frequency(_parameters.rc_flt_smp_rate, _parameters.rc_flt_cutoff);
    _filter_roll.reset(0.f);
    _filter_pitch.reset(0.f);
    _filter_yaw.reset(0.f);
    _filter_throttle.reset(0.f);
}

void
RCUpdate::rc_parameter_map_poll(bool forced)
{
    if (_rc_parameter_map_sub.updated() || forced) {
        _rc_parameter_map_sub.copy(&_rc_parameter_map);

        /* update parameter handles to which the RC channels are mapped */
        for (int i = 0; i < rc_parameter_map_s::RC_PARAM_MAP_NCHAN; i++) {
            if (_rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_PARAM_1 + i] < 0 || !_rc_parameter_map.valid[i]) {
                /* This RC channel is not mapped to a RC-Parameter Channel (e.g. RC_MAP_PARAM1 == 0)
                 * or no request to map this channel to a param has been sent via mavlink
                 */
                continue;
            }

            /* Set the handle by index if the index is set, otherwise use the id */
            if (_rc_parameter_map.param_index[i] >= 0) {
                _parameter_handles.rc_param[i] = param_for_used_index((unsigned)_rc_parameter_map.param_index[i]);

            } else {
                _parameter_handles.rc_param[i] = param_find(&_rc_parameter_map.param_id[i * (rc_parameter_map_s::PARAM_ID_LEN + 1)]);
            }

        }

        PX4_DEBUG("rc to parameter map updated");

        for (int i = 0; i < rc_parameter_map_s::RC_PARAM_MAP_NCHAN; i++) {
            PX4_DEBUG("\ti %d param_id %s scale %.3f value0 %.3f, min %.3f, max %.3f",
                  i,
                  &_rc_parameter_map.param_id[i * (rc_parameter_map_s::PARAM_ID_LEN + 1)],
                  (double)_rc_parameter_map.scale[i],
                  (double)_rc_parameter_map.value0[i],
                  (double)_rc_parameter_map.value_min[i],
                  (double)_rc_parameter_map.value_max[i]
                 );
        }
    }
}

float
RCUpdate::get_rc_value(uint8_t func, float min_value, float max_value)
{
    if (_rc.function[func] >= 0) {
        float value = _rc.channels[_rc.function[func]];
        return math::constrain(value, min_value, max_value);

    } else {
        return 0.0f;
    }
}

switch_pos_t
RCUpdate::get_rc_sw3pos_position(uint8_t func, float on_th, bool on_inv, float mid_th, bool mid_inv)
{
    if (_rc.function[func] >= 0) {
        float value = 0.5f * _rc.channels[_rc.function[func]] + 0.5f;

        if (on_inv ? value < on_th : value > on_th) {
            return manual_control_setpoint_s::SWITCH_POS_ON;

        } else if (mid_inv ? value < mid_th : value > mid_th) {
            return manual_control_setpoint_s::SWITCH_POS_MIDDLE;

        } else {
            return manual_control_setpoint_s::SWITCH_POS_OFF;
        }

    } else {
        return manual_control_setpoint_s::SWITCH_POS_NONE;
    }
}

switch_pos_t
RCUpdate::get_rc_sw2pos_position(uint8_t func, float on_th, bool on_inv)
{
    if (_rc.function[func] >= 0) {
        float value = 0.5f * _rc.channels[_rc.function[func]] + 0.5f;

        if (on_inv ? value < on_th : value > on_th) {
            return manual_control_setpoint_s::SWITCH_POS_ON;

        } else {
            return manual_control_setpoint_s::SWITCH_POS_OFF;
        }

    } else {
        return manual_control_setpoint_s::SWITCH_POS_NONE;
    }
}

void
RCUpdate::set_params_from_rc()
{
    for (int i = 0; i < rc_parameter_map_s::RC_PARAM_MAP_NCHAN; i++) {
        if (_rc.function[rc_channels_s::RC_CHANNELS_FUNCTION_PARAM_1 + i] < 0 || !_rc_parameter_map.valid[i]) {
            /* This RC channel is not mapped to a RC-Parameter Channel (e.g. RC_MAP_PARAM1 == 0)
             * or no request to map this channel to a param has been sent via mavlink
             */
            continue;
        }

        float rc_val = get_rc_value((rc_channels_s::RC_CHANNELS_FUNCTION_PARAM_1 + i), -1.0, 1.0);

        /* Check if the value has changed,
         * maybe we need to introduce a more aggressive limit here */
        if (rc_val > _param_rc_values[i] + FLT_EPSILON || rc_val < _param_rc_values[i] - FLT_EPSILON) {
            _param_rc_values[i] = rc_val;
            float param_val = math::constrain(
                          _rc_parameter_map.value0[i] + _rc_parameter_map.scale[i] * rc_val,
                          _rc_parameter_map.value_min[i], _rc_parameter_map.value_max[i]);
            param_set(_parameter_handles.rc_param[i], &param_val);
        }
    }
}

void
RCUpdate::Run()
{
    if (should_exit()) {
        _input_rc_sub.unregisterCallback();
        exit_and_cleanup();
        return;
    }

    perf_begin(_loop_perf);

    // check for parameter updates
    if (_parameter_update_sub.updated()) {
        // clear update
        parameter_update_s pupdate;
        _parameter_update_sub.copy(&pupdate);

        // update parameters from storage
        updateParams();
        parameters_updated();
    }

    rc_parameter_map_poll();

    /* read low-level values from FMU or IO RC inputs (PPM, Spektrum, S.Bus) */
    input_rc_s rc_input;

    if (_input_rc_sub.copy(&rc_input)) {

        /* detect RC signal loss */
        bool signal_lost = true;

        /* check flags and require at least four channels to consider the signal valid */
        if (rc_input.rc_lost || rc_input.rc_failsafe || rc_input.channel_count < 4) {
            /* signal is lost or no enough channels */
            signal_lost = true;

        } else {
            /* signal looks good */
            signal_lost = false;

            /* check failsafe */
            int8_t fs_ch = _rc.function[_parameters.rc_map_failsafe]; // get channel mapped to throttle

            if (_parameters.rc_map_failsafe > 0) { // if not 0, use channel number instead of rc.function mapping
                fs_ch = _parameters.rc_map_failsafe - 1;
            }

            if (_parameters.rc_fails_thr > 0 && fs_ch >= 0) {
                /* failsafe configured */
                if ((_parameters.rc_fails_thr < _parameters.min[fs_ch] && rc_input.values[fs_ch] < _parameters.rc_fails_thr) ||
                    (_parameters.rc_fails_thr > _parameters.max[fs_ch] && rc_input.values[fs_ch] > _parameters.rc_fails_thr)) {
                    /* failsafe triggered, signal is lost by receiver */
                    signal_lost = true;
                }
            }
        }

        unsigned channel_limit = rc_input.channel_count;

        if (channel_limit > RC_MAX_CHAN_COUNT) {
            channel_limit = RC_MAX_CHAN_COUNT;
        }

        /* read out and scale values from raw message even if signal is invalid */
        for (unsigned int i = 0; i < channel_limit; i++) {

            /*
             * 1) Constrain to min/max values, as later processing depends on bounds.
             */
            if (rc_input.values[i] < _parameters.min[i]) {
                rc_input.values[i] = _parameters.min[i];
            }

            if (rc_input.values[i] > _parameters.max[i]) {
                rc_input.values[i] = _parameters.max[i];
            }

            /*
             * 2) Scale around the mid point differently for lower and upper range.
             *
             * This is necessary as they don't share the same endpoints and slope.
             *
             * First normalize to 0..1 range with correct sign (below or above center),
             * the total range is 2 (-1..1).
             * If center (trim) == min, scale to 0..1, if center (trim) == max,
             * scale to -1..0.
             *
             * As the min and max bounds were enforced in step 1), division by zero
             * cannot occur, as for the case of center == min or center == max the if
             * statement is mutually exclusive with the arithmetic NaN case.
             *
             * DO NOT REMOVE OR ALTER STEP 1!
             */
            if (rc_input.values[i] > (_parameters.trim[i] + _parameters.dz[i])) {
                _rc.channels[i] = (rc_input.values[i] - _parameters.trim[i] - _parameters.dz[i]) / (float)(
                              _parameters.max[i] - _parameters.trim[i] - _parameters.dz[i]);

            } else if (rc_input.values[i] < (_parameters.trim[i] - _parameters.dz[i])) {
                _rc.channels[i] = (rc_input.values[i] - _parameters.trim[i] + _parameters.dz[i]) / (float)(
                              _parameters.trim[i] - _parameters.min[i] - _parameters.dz[i]);

            } else {
                /* in the configured dead zone, output zero */
                _rc.channels[i] = 0.0f;
            }

            _rc.channels[i] *= _parameters.rev[i];

            /* handle any parameter-induced blowups */
            if (!PX4_ISFINITE(_rc.channels[i])) {
                _rc.channels[i] = 0.0f;
            }
        }

        _rc.channel_count = rc_input.channel_count;
        _rc.rssi = rc_input.rssi;
        _rc.signal_lost = signal_lost;
        _rc.timestamp = rc_input.timestamp_last_signal;
        _rc.frame_drop_count = rc_input.rc_lost_frame_count;

        /* publish rc_channels topic even if signal is invalid, for debug */
        _rc_pub.publish(_rc);

        /* only publish manual control if the signal is still present and was present once */
        if (!signal_lost && rc_input.timestamp_last_signal > 0) {

            /* initialize manual setpoint */
            manual_control_setpoint_s manual{};
            /* set mode slot to unassigned */
            manual.mode_slot = manual_control_setpoint_s::MODE_SLOT_NONE;
            /* set the timestamp to the last signal time */
            manual.timestamp = rc_input.timestamp_last_signal;
            manual.data_source = manual_control_setpoint_s::SOURCE_RC;

            /* limit controls */
            manual.y = get_rc_value(rc_channels_s::RC_CHANNELS_FUNCTION_ROLL, -1.0, 1.0);
            manual.x = get_rc_value(rc_channels_s::RC_CHANNELS_FUNCTION_PITCH, -1.0, 1.0);
            manual.r = get_rc_value(rc_channels_s::RC_CHANNELS_FUNCTION_YAW, -1.0, 1.0);
            manual.z = get_rc_value(rc_channels_s::RC_CHANNELS_FUNCTION_THROTTLE, 0.0, 1.0);
            manual.flaps = get_rc_value(rc_channels_s::RC_CHANNELS_FUNCTION_FLAPS, -1.0, 1.0);
            manual.aux1 = get_rc_value(rc_channels_s::RC_CHANNELS_FUNCTION_AUX_1, -1.0, 1.0);
            manual.aux2 = get_rc_value(rc_channels_s::RC_CHANNELS_FUNCTION_AUX_2, -1.0, 1.0);
            manual.aux3 = get_rc_value(rc_channels_s::RC_CHANNELS_FUNCTION_AUX_3, -1.0, 1.0);
            manual.aux4 = get_rc_value(rc_channels_s::RC_CHANNELS_FUNCTION_AUX_4, -1.0, 1.0);
            manual.aux5 = get_rc_value(rc_channels_s::RC_CHANNELS_FUNCTION_AUX_5, -1.0, 1.0);
            manual.aux6 = get_rc_value(rc_channels_s::RC_CHANNELS_FUNCTION_AUX_6, -1.0, 1.0);

            /* filter controls */
            manual.y = math::constrain(_filter_roll.apply(manual.y), -1.f, 1.f);
            manual.x = math::constrain(_filter_pitch.apply(manual.x), -1.f, 1.f);
            manual.r = math::constrain(_filter_yaw.apply(manual.r), -1.f, 1.f);
            manual.z = math::constrain(_filter_throttle.apply(manual.z), 0.f, 1.f);

            if (_parameters.rc_map_flightmode > 0) {
                /* number of valid slots */
                const int num_slots = manual_control_setpoint_s::MODE_SLOT_NUM;

                /* the half width of the range of a slot is the total range
                 * divided by the number of slots, again divided by two
                 */
                const float slot_width_half = 2.0f / num_slots / 2.0f;

                /* min is -1, max is +1, range is 2. We offset below min and max */
                const float slot_min = -1.0f - 0.05f;
                const float slot_max = 1.0f + 0.05f;

                /* the slot gets mapped by first normalizing into a 0..1 interval using min
                 * and max. Then the right slot is obtained by multiplying with the number of
                 * slots. And finally we add half a slot width to ensure that integer rounding
                 * will take us to the correct final index.
                 */
                manual.mode_slot = (((((_rc.channels[_parameters.rc_map_flightmode - 1] - slot_min) * num_slots) + slot_width_half) /
                             (slot_max - slot_min)) + (1.0f / num_slots)) + 1;

                if (manual.mode_slot > num_slots) {
                    manual.mode_slot = num_slots;
                }
            }

            /* mode switches */
            manual.mode_switch = get_rc_sw3pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_MODE, _parameters.rc_auto_th,
                         _parameters.rc_auto_inv, _parameters.rc_assist_th, _parameters.rc_assist_inv);
            manual.rattitude_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_RATTITUDE,
                          _parameters.rc_rattitude_th,
                          _parameters.rc_rattitude_inv);
            manual.posctl_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_POSCTL, _parameters.rc_posctl_th,
                           _parameters.rc_posctl_inv);
            manual.return_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_RETURN, _parameters.rc_return_th,
                           _parameters.rc_return_inv);
            manual.loiter_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_LOITER, _parameters.rc_loiter_th,
                           _parameters.rc_loiter_inv);
            manual.acro_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_ACRO, _parameters.rc_acro_th,
                         _parameters.rc_acro_inv);
            manual.offboard_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_OFFBOARD,
                         _parameters.rc_offboard_th, _parameters.rc_offboard_inv);
            manual.kill_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_KILLSWITCH,
                         _parameters.rc_killswitch_th, _parameters.rc_killswitch_inv);
            manual.arm_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_ARMSWITCH,
                        _parameters.rc_armswitch_th, _parameters.rc_armswitch_inv);
            manual.transition_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_TRANSITION,
                           _parameters.rc_trans_th, _parameters.rc_trans_inv);
            manual.gear_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_GEAR,
                         _parameters.rc_gear_th, _parameters.rc_gear_inv);
            manual.stab_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_STAB,
                         _parameters.rc_stab_th, _parameters.rc_stab_inv);
            manual.man_switch = get_rc_sw2pos_position(rc_channels_s::RC_CHANNELS_FUNCTION_MAN,
                        _parameters.rc_man_th, _parameters.rc_man_inv);

            /* publish manual_control_setpoint topic */
            _manual_control_pub.publish(manual);

            /* copy from mapped manual control to control group 3 */
            actuator_controls_s actuator_group_3{};

            actuator_group_3.timestamp = rc_input.timestamp_last_signal;

            actuator_group_3.control[0] = manual.y;
            actuator_group_3.control[1] = manual.x;
            actuator_group_3.control[2] = manual.r;
            actuator_group_3.control[3] = manual.z;
            actuator_group_3.control[4] = manual.flaps;
            actuator_group_3.control[5] = manual.aux1;
            actuator_group_3.control[6] = manual.aux2;
            actuator_group_3.control[7] = manual.aux3;

            /* publish actuator_controls_3 topic */
            _actuator_group_3_pub.publish(actuator_group_3);

            /* Update parameters from RC Channels (tuning with RC) if activated */
            if (hrt_elapsed_time(&_last_rc_to_param_map_time) > 1e6) {
                set_params_from_rc();
                _last_rc_to_param_map_time = hrt_absolute_time();
            }
        }
    }

    perf_end(_loop_perf);
}

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

    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
RCUpdate::print_status()
{
    PX4_INFO("Running");
    perf_print_counter(_loop_perf);

    return 0;
}

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

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

    PRINT_MODULE_DESCRIPTION(
        R"DESCR_STR(
### Description
The rc_update module handles RC channel mapping: read the raw input channels (`input_rc`),
then apply the calibration, map the RC channels to the configured channels & mode switches,
low-pass filter, and then publish as `rc_channels` and `manual_control_setpoint`.

### Implementation
To reduce control latency, the module is scheduled on input_rc publications.

)DESCR_STR");

    PRINT_MODULE_USAGE_NAME("rc_update", "system");
    PRINT_MODULE_USAGE_COMMAND("start");
    PRINT_MODULE_USAGE_DEFAULT_COMMANDS();

    return 0;
}

} // namespace RCUpdate

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