ardupilot/libraries/AP_Motors/AP_MotorsMatrix.cpp

// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
 *       AP_MotorsMatrix.cpp - ArduCopter motors library
 *       Code by RandyMackay. DIYDrones.com
 *
 *       This library is free software; you can redistribute it and/or
 *   modify it under the terms of the GNU Lesser General Public
 *   License as published by the Free Software Foundation; either
 *   version 2.1 of the License, or (at your option) any later version.
 */
#include <AP_HAL.h>
#include "AP_MotorsMatrix.h"

extern const AP_HAL::HAL& hal;

// Init
void AP_MotorsMatrix::Init()
{
    // call parent Init function to set-up throttle curve
    AP_Motors::Init();

    // setup the motors
    setup_motors();

    // enable fast channels or instant pwm
    set_update_rate(_speed_hz);
}

// set update rate to motors - a value in hertz
void AP_MotorsMatrix::set_update_rate( uint16_t speed_hz )
{
    int8_t i;

    // record requested speed
    _speed_hz = speed_hz;

    // check each enabled motor
    uint32_t mask = 0;
    for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
        if( motor_enabled[i] ) {
		mask |= 1U << _motor_to_channel_map[i];
        }
    }
    hal.rcout->set_freq( mask, _speed_hz );
}

// set frame orientation (normally + or X)
void AP_MotorsMatrix::set_frame_orientation( uint8_t new_orientation )
{
    // return if nothing has changed
    if( new_orientation == _frame_orientation ) {
        return;
    }

    // call parent
    AP_Motors::set_frame_orientation( new_orientation );

    // setup the motors
    setup_motors();

    // enable fast channels or instant pwm
    set_update_rate(_speed_hz);
}

// enable - starts allowing signals to be sent to motors
void AP_MotorsMatrix::enable()
{
    int8_t i;

    // enable output channels
    for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
        if( motor_enabled[i] ) {
            hal.rcout->enable_ch(_motor_to_channel_map[i]);
        }
    }
}

// output_min - sends minimum values out to the motors
void AP_MotorsMatrix::output_min()
{
    int8_t i;

    // fill the motor_out[] array for HIL use and send minimum value to each motor
    for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
        if( motor_enabled[i] ) {
            motor_out[i] = _rc_throttle->radio_min;
            hal.rcout->write(_motor_to_channel_map[i], motor_out[i]);
        }
    }
}

#ifdef AP_MOTORS_MATRIX_SCALING_STABILITY_PATCH
// output_armed - sends commands to the motors
// includes new scaling stability patch
void AP_MotorsMatrix::output_armed()
{
    int8_t i;
    int16_t out_min = _rc_throttle->radio_min + _min_throttle;
    int16_t out_max = _rc_throttle->radio_max;
    int16_t out_mid = (out_min+out_max)/2;
    int16_t out_max_range; // the is the allowable throttle out setting that allowes maximum roll, pitch and yaw range
    float rpy_scale = 1.0; // this is used to scale the roll, pitch and yaw to fit within the motor limits

    int16_t rpy_out[AP_MOTORS_MAX_NUM_MOTORS]; // buffer so we don't have to multiply coefficients multiple times.

    int16_t rpy_low = 0;    // lowest motor value
    int16_t rpy_high = 0;   // highest motor value
    int16_t yaw_allowed;    // amount of yaw we can fit in
    int16_t thr_adj;        // how far we move the throttle point from out_max_range

    // initialize reached_limit flag
    _reached_limit = AP_MOTOR_NO_LIMITS_REACHED;

    // Throttle is 0 to 1000 only
    // To-Do: we should not really be limiting this here because we don't "own" this _rc_throttle object
    _rc_throttle->servo_out = constrain_int16(_rc_throttle->servo_out, 0, _max_throttle);

    // capture desired roll, pitch, yaw and throttle from receiver
    _rc_roll->calc_pwm();
    _rc_pitch->calc_pwm();
    _rc_throttle->calc_pwm();
    _rc_yaw->calc_pwm();

    // if we are not sending a throttle output, we cut the motors
    if (_rc_throttle->servo_out == 0) {
        for (i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++) {
            if (motor_enabled[i]) {
                motor_out[i]    = _rc_throttle->radio_min;
            }
        }

        // Every thing is limited
        _reached_limit |= AP_MOTOR_ROLLPITCH_LIMIT | AP_MOTOR_YAW_LIMIT | AP_MOTOR_THROTTLE_LIMIT;

    } else {

        // check if throttle is below limit
        if (_rc_throttle->radio_out < out_min) {
            _reached_limit |= AP_MOTOR_THROTTLE_LIMIT;
        }

        // calculate roll and pitch for each motor
        for (i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++) {
            if (motor_enabled[i]) {
                rpy_out[i] = _rc_roll->pwm_out * _roll_factor[i] +
                             _rc_pitch->pwm_out * _pitch_factor[i];

                // record lowest roll pitch command
                if (rpy_out[i] < rpy_low) {
                    rpy_low = rpy_out[i];
                }
                // record highest roll pich command
                if (rpy_out[i] > rpy_high) {
                    rpy_high = rpy_out[i];
                }
            }
        }

        // calculate throttle that gives most possible room for yaw (range 1000 ~ 2000)
        // this value is either:
        //      mid throttle - average of highest and lowest motor
        //      the higher of the pilot's throttle input or hover-throttle -- this ensure we never increase the throttle above hover throttle unless the pilot has commanded that
        int16_t motor_mid = (rpy_low+rpy_high)/2;
        out_max_range = min(out_mid - motor_mid, max(_rc_throttle->radio_out, (_rc_throttle->radio_out+_hover_out)/2));

        // calculate amount of yaw we can fit into the throttle range
        // this is always equal to or less than the requested yaw from the pilot or rate controller
        yaw_allowed = min(out_max - out_max_range, out_max_range - out_min) - (rpy_high-rpy_low)/2;
        yaw_allowed = max(yaw_allowed, AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM);     // allow at least 200 of yaw

        if (_rc_yaw->pwm_out > 0) {
            // if yawing right
            yaw_allowed = min(yaw_allowed, _rc_yaw->pwm_out);     // minimum that we can fit vs what we have asked for
            // we haven't even been able to apply full yaw command
            _reached_limit |= AP_MOTOR_YAW_LIMIT;
        }else if(_rc_yaw->pwm_out < 0) {
            // if yawing left
            yaw_allowed = max(-yaw_allowed, _rc_yaw->pwm_out);
            // we haven't even been able to apply full yaw command
            _reached_limit |= AP_MOTOR_YAW_LIMIT;
        }else{
            yaw_allowed = 0;
        }

        // add yaw to intermediate numbers for each motor
        for (i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++) {
            if (motor_enabled[i]) {
                rpy_out[i] =    rpy_out[i] +
                                yaw_allowed * _yaw_factor[i];

                // record lowest roll+pitch+yaw command
                if( rpy_out[i] < rpy_low ) {
                    rpy_low = rpy_out[i];
                }
                // record highest roll+pitch+yaw command
                if( rpy_out[i] > rpy_high) {
                    rpy_high = rpy_out[i];
                }
            }
        }

        // check everything fits
        thr_adj = _rc_throttle->radio_out - out_max_range;

        if (thr_adj > 0) {
            // increase throttle as close as possible to requested throttle
            // without going over out_max
            if (thr_adj > out_max-(rpy_high+out_max_range)){
                thr_adj = out_max-(rpy_high+out_max_range);
                // we haven't even been able to apply full throttle command
                _reached_limit |= AP_MOTOR_THROTTLE_LIMIT;
            }
        }else if(thr_adj < 0){
            // decrease throttle as close as possible to requested throttle
            // without going under out_min or over out_max
            // earlier code ensures we can't break both boundaryies
            thr_adj = max(min(thr_adj,out_max-(rpy_high+out_max_range)), min(out_min-(rpy_low+out_max_range),0));
        }

        // do we need to reduce roll, pitch, yaw command
        // earlier code does not allow both limit's to be passed simultainiously with abs(_yaw_factor)<1
        if ((rpy_low+out_max_range)+thr_adj < out_min){
            rpy_scale = (float)(out_min-thr_adj-out_max_range)/rpy_low;
            // we haven't even been able to apply full roll, pitch and minimal yaw without scaling
            _reached_limit |= AP_MOTOR_ROLLPITCH_LIMIT | AP_MOTOR_YAW_LIMIT;
        }else if((rpy_high+out_max_range)+thr_adj > out_max){
            rpy_scale = (float)(out_max-thr_adj-out_max_range)/rpy_high;
            // we haven't even been able to apply full roll, pitch and minimal yaw without scaling
            _reached_limit |= AP_MOTOR_ROLLPITCH_LIMIT | AP_MOTOR_YAW_LIMIT;
        }

        // add scaled roll, pitch, constrained yaw and throttle for each motor
        for (i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++) {
            if (motor_enabled[i]) {
                motor_out[i] = out_max_range+thr_adj +
                               rpy_scale*rpy_out[i];
            }
        }

        // adjust for throttle curve
        if (_throttle_curve_enabled) {
            for (i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++) {
                if (motor_enabled[i]) {
                    motor_out[i] = _throttle_curve.get_y(motor_out[i]);
                }
            }
        }
        // clip motor output if required (shouldn't be)
        for (i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++) {
            if (motor_enabled[i]) {
                motor_out[i] = constrain_int16(motor_out[i], out_min, out_max);
            }
        }
    }

    // send output to each motor
    for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
        if( motor_enabled[i] ) {
            hal.rcout->write(_motor_to_channel_map[i], motor_out[i]);
        }
    }
}
#else
// output_armed - sends commands to the motors
void AP_MotorsMatrix::output_armed()
{
    int8_t i;
    int16_t out_min = _rc_throttle->radio_min;
    int16_t out_max = _rc_throttle->radio_max;
    int16_t rc_yaw_constrained_pwm;
    int16_t rc_yaw_excess;
    int16_t upper_margin, lower_margin;
    int16_t motor_adjustment = 0;
    int16_t yaw_to_execute = 0;

    // initialize reached_limit flag
    _reached_limit = AP_MOTOR_NO_LIMITS_REACHED;

    // Throttle is 0 to 1000 only
    _rc_throttle->servo_out = constrain_int16(_rc_throttle->servo_out, 0, _max_throttle);

    // capture desired roll, pitch, yaw and throttle from receiver
    _rc_roll->calc_pwm();
    _rc_pitch->calc_pwm();
    _rc_throttle->calc_pwm();
    _rc_yaw->calc_pwm();

    // if we are not sending a throttle output, we cut the motors
    if(_rc_throttle->servo_out == 0) {
        for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
            if( motor_enabled[i] ) {
                motor_out[i]    = _rc_throttle->radio_min;
            }
        }
        // if we have any roll, pitch or yaw input then it's breaching the limit
        if( _rc_roll->pwm_out != 0 || _rc_pitch->pwm_out != 0 ) {
            _reached_limit |= AP_MOTOR_ROLLPITCH_LIMIT;
        }
        if( _rc_yaw->pwm_out != 0 ) {
            _reached_limit |= AP_MOTOR_YAW_LIMIT;
        }
    } else {    // non-zero throttle

        out_min = _rc_throttle->radio_min + _min_throttle;

        // initialise rc_yaw_contrained_pwm that we will certainly output and rc_yaw_excess that we will do on best-efforts basis.
        // Note: these calculations and many others below depend upon _yaw_factors always being 0, -1 or 1.
        if( _rc_yaw->pwm_out < -AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM ) {
            rc_yaw_constrained_pwm = -AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM;
            rc_yaw_excess = _rc_yaw->pwm_out+AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM;
        }else if( _rc_yaw->pwm_out > AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM ) {
            rc_yaw_constrained_pwm = AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM;
            rc_yaw_excess = _rc_yaw->pwm_out-AP_MOTORS_MATRIX_YAW_LOWER_LIMIT_PWM;
        }else{
            rc_yaw_constrained_pwm = _rc_yaw->pwm_out;
            rc_yaw_excess = 0;
        }

        // initialise upper and lower margins
        upper_margin = lower_margin = out_max - out_min;

        // add roll, pitch, throttle and constrained yaw for each motor
        for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
            if( motor_enabled[i] ) {
                motor_out[i] = _rc_throttle->radio_out +
                               _rc_roll->pwm_out * _roll_factor[i] +
                               _rc_pitch->pwm_out * _pitch_factor[i] +
                               rc_yaw_constrained_pwm * _yaw_factor[i];

                // calculate remaining room between fastest running motor and top of pwm range
                if( out_max - motor_out[i] < upper_margin) {
                    upper_margin = out_max - motor_out[i];
                }
                // calculate remaining room between slowest running motor and bottom of pwm range
                if( motor_out[i] - out_min < lower_margin ) {
                    lower_margin = motor_out[i] - out_min;
                }
            }
        }

        // if motors are running too fast and we have enough room below, lower overall throttle
        if( upper_margin < 0 || lower_margin < 0 ) {

            // calculate throttle adjustment that equalizes upper and lower margins.  We will never push the throttle beyond this point
            motor_adjustment = (upper_margin - lower_margin) / 2;      // i.e. if overflowed by 20 on top, 30 on bottom, upper_margin = -20, lower_margin = -30.  will adjust motors -5.

            // if we have overflowed on the top, reduce but no more than to the mid point
            if( upper_margin < 0 ) {
                motor_adjustment = max(upper_margin, motor_adjustment);
            }

            // if we have underflowed on the bottom, increase throttle but no more than to the mid point
            if( lower_margin < 0 ) {
                motor_adjustment = min(-lower_margin, motor_adjustment);
            }
        }

        // move throttle up or down to to pull within tolerance
        if( motor_adjustment != 0 ) {
            for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
                if( motor_enabled[i] ) {
                    motor_out[i] += motor_adjustment;
                }
            }

            // we haven't even been able to apply roll, pitch and minimal yaw without adjusting throttle so mark all limits as breached
            _reached_limit |= AP_MOTOR_ROLLPITCH_LIMIT | AP_MOTOR_YAW_LIMIT | AP_MOTOR_THROTTLE_LIMIT;
        }

        // if we didn't give all the yaw requested, calculate how much additional yaw we can add
        if( rc_yaw_excess != 0 ) {

            // try for everything
            yaw_to_execute = rc_yaw_excess;

            // loop through motors and reduce as necessary
            for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
                if( motor_enabled[i] && _yaw_factor[i] != 0 ) {

                    // calculate upper and lower margins for this motor
                    upper_margin = max(0,out_max - motor_out[i]);
                    lower_margin = max(0,motor_out[i] - out_min);

                    // motor is increasing, check upper limit
                    if( rc_yaw_excess > 0 && _yaw_factor[i] > 0 ) {
                        yaw_to_execute = min(yaw_to_execute, upper_margin);
                    }

                    // motor is decreasing, check lower limit
                    if( rc_yaw_excess > 0 && _yaw_factor[i] < 0 ) {
                        yaw_to_execute = min(yaw_to_execute, lower_margin);
                    }

                    // motor is decreasing, check lower limit
                    if( rc_yaw_excess < 0 && _yaw_factor[i] > 0 ) {
                        yaw_to_execute = max(yaw_to_execute, -lower_margin);
                    }

                    // motor is increasing, check upper limit
                    if( rc_yaw_excess < 0 && _yaw_factor[i] < 0 ) {
                        yaw_to_execute = max(yaw_to_execute, -upper_margin);
                    }
                }
            }
            // check yaw_to_execute is reasonable
            if( yaw_to_execute != 0 && ((yaw_to_execute>0 && rc_yaw_excess>0) || (yaw_to_execute<0 && rc_yaw_excess<0)) ) {
                // add the additional yaw
                for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
                    if( motor_enabled[i] ) {
                        motor_out[i] += _yaw_factor[i] * yaw_to_execute;
                    }
                }
            }
            // mark yaw limit reached if we didn't get everything we asked for
            if( yaw_to_execute != rc_yaw_excess ) {
                _reached_limit |= AP_MOTOR_YAW_LIMIT;
            }
        }

        // adjust for throttle curve
        if( _throttle_curve_enabled ) {
            for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
                if( motor_enabled[i] ) {
                    motor_out[i] = _throttle_curve.get_y(motor_out[i]);
                }
            }
        }

        // clip motor output if required (shouldn't be)
        for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
            if( motor_enabled[i] ) {
                motor_out[i] = constrain_int16(motor_out[i], out_min, out_max);
            }
        }
    }

    // send output to each motor
    for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
        if( motor_enabled[i] ) {
            hal.rcout->write(_motor_to_channel_map[i], motor_out[i]);
        }
    }
}
#endif  // AP_MOTORS_MATRIX_SCALING_STABILITY_PATCH

// output_disarmed - sends commands to the motors
void AP_MotorsMatrix::output_disarmed()
{
    // Send minimum values to all motors
    output_min();
}

// output_disarmed - sends commands to the motors
void AP_MotorsMatrix::output_test()
{
    uint8_t min_order, max_order;
    uint8_t i,j;

    // find min and max orders
    min_order = _test_order[0];
    max_order = _test_order[0];
    for(i=1; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
        if( _test_order[i] < min_order )
            min_order = _test_order[i];
        if( _test_order[i] > max_order )
            max_order = _test_order[i];
    }

    // shut down all motors
    output_min();

    // first delay is longer
    hal.scheduler->delay(4000);

    // loop through all the possible orders spinning any motors that match that description
    for( i=min_order; i<=max_order; i++ ) {
        for( j=0; j<AP_MOTORS_MAX_NUM_MOTORS; j++ ) {
            if( motor_enabled[j] && _test_order[j] == i ) {
                // turn on this motor and wait 1/3rd of a second
                hal.rcout->write(_motor_to_channel_map[j], _rc_throttle->radio_min + _min_throttle);
                hal.scheduler->delay(300);
                hal.rcout->write(_motor_to_channel_map[j], _rc_throttle->radio_min);
                hal.scheduler->delay(2000);
            }
        }
    }

    // shut down all motors
    output_min();
}

// add_motor
void AP_MotorsMatrix::add_motor_raw(int8_t motor_num, float roll_fac, float pitch_fac, float yaw_fac, uint8_t testing_order)
{
    // ensure valid motor number is provided
    if( motor_num >= 0 && motor_num < AP_MOTORS_MAX_NUM_MOTORS ) {

        // increment number of motors if this motor is being newly motor_enabled
        if( !motor_enabled[motor_num] ) {
            motor_enabled[motor_num] = true;
            _num_motors++;
        }

        // set roll, pitch, thottle factors and opposite motor (for stability patch)
        _roll_factor[motor_num] = roll_fac;
        _pitch_factor[motor_num] = pitch_fac;
        _yaw_factor[motor_num] = yaw_fac;

        // set order that motor appears in test
        _test_order[motor_num] = testing_order;
    }
}

// add_motor using just position and prop direction
void AP_MotorsMatrix::add_motor(int8_t motor_num, float angle_degrees, float yaw_factor, uint8_t testing_order)
{
    // call raw motor set-up method
    add_motor_raw(
        motor_num,
        cosf(radians(angle_degrees + 90)),               // roll factor
        cosf(radians(angle_degrees)),                    // pitch factor
        yaw_factor,                                      // yaw factor
        testing_order);

}

// remove_motor - disabled motor and clears all roll, pitch, throttle factors for this motor
void AP_MotorsMatrix::remove_motor(int8_t motor_num)
{
    // ensure valid motor number is provided
    if( motor_num >= 0 && motor_num < AP_MOTORS_MAX_NUM_MOTORS ) {

        // if the motor was enabled decrement the number of motors
        if( motor_enabled[motor_num] )
            _num_motors--;

        // disable the motor, set all factors to zero
        motor_enabled[motor_num] = false;
        _roll_factor[motor_num] = 0;
        _pitch_factor[motor_num] = 0;
        _yaw_factor[motor_num] = 0;
    }
}

// remove_all_motors - removes all motor definitions
void AP_MotorsMatrix::remove_all_motors()
{
    for( int8_t i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
        remove_motor(i);
    }
    _num_motors = 0;
}