ardupilot/libraries/AP_Motors/AP_MotorsMatrix.cpp

/*
 *       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_MotorsMatrix.h"

// Init
void AP_MotorsMatrix::Init()
{
    int8_t i;

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

    // setup the motors
    setup_motors();

    // double check that opposite motor definitions are ok
    for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
        if( opposite_motor[i] <= 0 || opposite_motor[i] >= AP_MOTORS_MAX_NUM_MOTORS || !motor_enabled[opposite_motor[i]] )
            opposite_motor[i] = AP_MOTORS_MATRIX_MOTOR_UNDEFINED;
    }

    // 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 )
{
    uint32_t fast_channel_mask = 0;
    int8_t i;

    // record requested speed
    _speed_hz = speed_hz;

    // check each enabled motor
    for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
        if( motor_enabled[i] ) {
            // set-up fast channel mask
            fast_channel_mask |= _BV(_motor_to_channel_map[i]);                 // add to fast channel map
        }
    }

    // enable fast channels
    _rc->SetFastOutputChannels(fast_channel_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] ) {
            _rc->enable_out(_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;
            _rc->OutputCh(_motor_to_channel_map[i], motor_out[i]);
        }
    }
}

// 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;

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

    if(_rc_throttle->servo_out > 0)
        out_min = _rc_throttle->radio_min + _min_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();

    // 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;
            }
        }
    }

    // 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;
                }
            }
        }
    }

    // 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(motor_out[i], out_min, out_max);
        }
    }

#if CUT_MOTORS == ENABLED
    // 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;
            }
        }
    }
#endif

    // send output to each motor
    for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
        if( motor_enabled[i] ) {
            _rc->OutputCh(_motor_to_channel_map[i], motor_out[i]);
        }
    }
}

// output_disarmed - sends commands to the motors
void AP_MotorsMatrix::output_disarmed()
{
    if(_rc_throttle->control_in > 0) {
        // we have pushed up the throttle
        // remove safety for auto pilot
        _auto_armed = true;
    }

    // Send minimum values to all motors
    output_min();
}

// output_disarmed - sends commands to the motors
void AP_MotorsMatrix::output_test()
{
    int8_t min_order, max_order;
    int8_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
    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
                _rc->OutputCh(_motor_to_channel_map[j], _rc_throttle->radio_min + 100);
                delay(300);
                _rc->OutputCh(_motor_to_channel_map[j], _rc_throttle->radio_min);
                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, int8_t opposite_motor_num, int8_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 opposite motor after checking it's somewhat valid
        if( opposite_motor_num == AP_MOTORS_MATRIX_MOTOR_UNDEFINED || (opposite_motor_num >=0 && opposite_motor_num < AP_MOTORS_MAX_NUM_MOTORS) ) {
            opposite_motor[motor_num] = opposite_motor_num;
        }else{
            opposite_motor[motor_num] = AP_MOTORS_MATRIX_MOTOR_UNDEFINED;
        }

        // set order that motor appears in test
        if( testing_order == AP_MOTORS_MATRIX_ORDER_UNDEFINED ) {
            test_order[motor_num] = motor_num;
        }else{
            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, int8_t direction, int8_t opposite_motor_num, int8_t testing_order)
{
    // call raw motor set-up method
    add_motor_raw(
        motor_num,
        cos(radians(angle_degrees + 90)),               // roll factor
        cos(radians(angle_degrees)),                    // pitch factor
        (float)direction,                                               // yaw factor
        opposite_motor_num,
        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)
{
    int8_t i;

    // 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;
        opposite_motor[motor_num] = AP_MOTORS_MATRIX_MOTOR_UNDEFINED;
    }

    // if another motor has referred to this motor as it's opposite, remove that reference
    for( i=0; i<AP_MOTORS_MAX_NUM_MOTORS; i++ ) {
        if( opposite_motor[i] == motor_num )
            opposite_motor[i] = AP_MOTORS_MATRIX_MOTOR_UNDEFINED;
    }
}

// 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;
}