ardupilot/libraries/AP_Motors/AP_MotorsSingle.cpp

// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/*
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

/*
 *       AP_MotorsSingle.cpp - ArduCopter motors library
 *       Code by RandyMackay. DIYDrones.com
 *
 */

#include <AP_HAL/AP_HAL.h>
#include <AP_Math/AP_Math.h>
#include "AP_MotorsSingle.h"

extern const AP_HAL::HAL& hal;


const AP_Param::GroupInfo AP_MotorsSingle::var_info[] = {
    // variables from parent vehicle
    AP_NESTEDGROUPINFO(AP_MotorsMulticopter, 0),

    // parameters 1 ~ 29 were reserved for tradheli
    // parameters 30 ~ 39 reserved for tricopter
    // parameters 40 ~ 49 for single copter and coax copter (these have identical parameter files)

    // 40 was ROLL_SV_REV
    // 41 was PITCH_SV_REV
	// 42 was YAW_SV_REV

	// @Param: SV_SPEED
    // @DisplayName: Servo speed 
    // @Description: Servo update speed in hz
    // @Values: 50, 125, 250
    AP_GROUPINFO("SV_SPEED", 43, AP_MotorsSingle, _servo_speed, AP_MOTORS_SINGLE_SPEED_DIGITAL_SERVOS),

    // @Group: SV1_
    // @Path: ../RC_Channel/RC_Channel.cpp
    AP_SUBGROUPINFO(_servo1, "SV1_", 44, AP_MotorsSingle, RC_Channel),
    // @Group: SV2_
    // @Path: ../RC_Channel/RC_Channel.cpp
    AP_SUBGROUPINFO(_servo2, "SV2_", 45, AP_MotorsSingle, RC_Channel),
    // @Group: SV3_
    // @Path: ../RC_Channel/RC_Channel.cpp
    AP_SUBGROUPINFO(_servo3, "SV3_", 46, AP_MotorsSingle, RC_Channel),
    // @Group: SV4_
    // @Path: ../RC_Channel/RC_Channel.cpp
    AP_SUBGROUPINFO(_servo4, "SV4_", 47, AP_MotorsSingle, RC_Channel),

    AP_GROUPEND
};
// init
void AP_MotorsSingle::Init()
{
    // set update rate for the 3 motors (but not the servo on channel 7)
    set_update_rate(_speed_hz);

    // set the motor_enabled flag so that the main ESC can be calibrated like other frame types
    motor_enabled[AP_MOTORS_MOT_5] = true;
    motor_enabled[AP_MOTORS_MOT_6] = true;

    // we set four servos to angle
    _servo1.set_type(RC_CHANNEL_TYPE_ANGLE);
    _servo2.set_type(RC_CHANNEL_TYPE_ANGLE);
    _servo3.set_type(RC_CHANNEL_TYPE_ANGLE);
    _servo4.set_type(RC_CHANNEL_TYPE_ANGLE);
    _servo1.set_angle(AP_MOTORS_SINGLE_SERVO_INPUT_RANGE);
    _servo2.set_angle(AP_MOTORS_SINGLE_SERVO_INPUT_RANGE);
    _servo3.set_angle(AP_MOTORS_SINGLE_SERVO_INPUT_RANGE);
    _servo4.set_angle(AP_MOTORS_SINGLE_SERVO_INPUT_RANGE);

    // disable CH7 from being used as an aux output (i.e. for camera gimbal, etc)
    RC_Channel_aux::disable_aux_channel(CH_7);
}

// set update rate to motors - a value in hertz
void AP_MotorsSingle::set_update_rate( uint16_t speed_hz )
{
    // record requested speed
    _speed_hz = speed_hz;

    // set update rate for the 3 motors (but not the servo on channel 7)
    uint32_t mask = 
        1U << AP_MOTORS_MOT_1 |
        1U << AP_MOTORS_MOT_2 |
        1U << AP_MOTORS_MOT_3 |
        1U << AP_MOTORS_MOT_4 ;
    rc_set_freq(mask, _servo_speed);
    uint32_t mask2 =
        1U << AP_MOTORS_MOT_5 |
        1U << AP_MOTORS_MOT_6 ;
    rc_set_freq(mask2, _speed_hz);
}

// enable - starts allowing signals to be sent to motors
void AP_MotorsSingle::enable()
{
    // enable output channels
    rc_enable_ch(AP_MOTORS_MOT_1);
    rc_enable_ch(AP_MOTORS_MOT_2);
    rc_enable_ch(AP_MOTORS_MOT_3);
    rc_enable_ch(AP_MOTORS_MOT_4);
    rc_enable_ch(AP_MOTORS_MOT_5);
    rc_enable_ch(AP_MOTORS_MOT_6);
}

// output_min - sends minimum values out to the motor and trim values to the servos
void AP_MotorsSingle::output_min()
{
    // send minimum value to each motor
    hal.rcout->cork();
    rc_write(AP_MOTORS_MOT_1, _servo1.radio_trim);
    rc_write(AP_MOTORS_MOT_2, _servo2.radio_trim);
    rc_write(AP_MOTORS_MOT_3, _servo3.radio_trim);
    rc_write(AP_MOTORS_MOT_4, _servo4.radio_trim);
    rc_write(AP_MOTORS_MOT_5, _throttle_radio_min);
    rc_write(AP_MOTORS_MOT_6, _throttle_radio_min);
    hal.rcout->push();
}

void AP_MotorsSingle::output_to_motors()
{
    switch (_multicopter_flags.spool_mode) {
        case SHUT_DOWN:
            // sends minimum values out to the motors
            hal.rcout->cork();
            rc_write(AP_MOTORS_MOT_1, calc_pwm_output_1to1(_roll_radio_passthrough+_yaw_radio_passthrough, _servo1));
            rc_write(AP_MOTORS_MOT_2, calc_pwm_output_1to1(_pitch_radio_passthrough+_yaw_radio_passthrough, _servo2));
            rc_write(AP_MOTORS_MOT_3, calc_pwm_output_1to1(-_roll_radio_passthrough+_yaw_radio_passthrough, _servo3));
            rc_write(AP_MOTORS_MOT_4, calc_pwm_output_1to1(-_pitch_radio_passthrough+_yaw_radio_passthrough, _servo4));
            rc_write(AP_MOTORS_MOT_5, _throttle_radio_min);
            rc_write(AP_MOTORS_MOT_6, _throttle_radio_min);
            hal.rcout->push();
            break;
        case SPIN_WHEN_ARMED:
            // sends output to motors when armed but not flying
            hal.rcout->cork();
            rc_write(AP_MOTORS_MOT_1, calc_pwm_output_1to1(_throttle_low_end_pct * _actuator_out[0], _servo1));
            rc_write(AP_MOTORS_MOT_2, calc_pwm_output_1to1(_throttle_low_end_pct * _actuator_out[1], _servo2));
            rc_write(AP_MOTORS_MOT_3, calc_pwm_output_1to1(_throttle_low_end_pct * _actuator_out[2], _servo3));
            rc_write(AP_MOTORS_MOT_4, calc_pwm_output_1to1(_throttle_low_end_pct * _actuator_out[3], _servo4));
            rc_write(AP_MOTORS_MOT_5, constrain_int16(_throttle_radio_min + _throttle_low_end_pct * _min_throttle, _throttle_radio_min, _throttle_radio_min + _min_throttle));
            rc_write(AP_MOTORS_MOT_6, constrain_int16(_throttle_radio_min + _throttle_low_end_pct * _min_throttle, _throttle_radio_min, _throttle_radio_min + _min_throttle));
            hal.rcout->push();
            break;
        case SPOOL_UP:
        case THROTTLE_UNLIMITED:
        case SPOOL_DOWN:
            // set motor output based on thrust requests
            hal.rcout->cork();
            rc_write(AP_MOTORS_MOT_1, calc_pwm_output_1to1(_actuator_out[0], _servo1));
            rc_write(AP_MOTORS_MOT_2, calc_pwm_output_1to1(_actuator_out[1], _servo2));
            rc_write(AP_MOTORS_MOT_3, calc_pwm_output_1to1(_actuator_out[2], _servo3));
            rc_write(AP_MOTORS_MOT_4, calc_pwm_output_1to1(_actuator_out[3], _servo4));
            rc_write(AP_MOTORS_MOT_5, calc_thrust_to_pwm(_thrust_out));
            rc_write(AP_MOTORS_MOT_6, calc_thrust_to_pwm(_thrust_out));
            hal.rcout->push();
            break;
    }
}

// get_motor_mask - returns a bitmask of which outputs are being used for motors or servos (1 means being used)
//  this can be used to ensure other pwm outputs (i.e. for servos) do not conflict
uint16_t AP_MotorsSingle::get_motor_mask()
{
    uint32_t mask =
        1U << AP_MOTORS_MOT_1 |
        1U << AP_MOTORS_MOT_2 |
        1U << AP_MOTORS_MOT_3 |
        1U << AP_MOTORS_MOT_4 |
        1U << AP_MOTORS_MOT_5 |
        1U << AP_MOTORS_MOT_6;
    return rc_map_mask(mask);
}

// sends commands to the motors
void AP_MotorsSingle::output_armed_stabilizing()
{
    uint8_t i;                          // general purpose counter
    float   roll_thrust;                // roll thrust input value, +/- 1.0
    float   pitch_thrust;               // pitch thrust input value, +/- 1.0
    float   yaw_thrust;                 // yaw thrust input value, +/- 1.0
    float   throttle_thrust;            // throttle thrust input value, 0.0 - 1.0
    float   thrust_min_rp;              // the minimum throttle setting that will not limit the roll and pitch output
    float   thr_adj;                    // the difference between the pilot's desired throttle and throttle_thrust_best_rpy
    float   throttle_thrust_hover = get_hover_throttle_as_high_end_pct();   // throttle hover thrust value, 0.0 - 1.0
    float   throttle_thrust_rpy_mix;    // partial calculation of throttle_thrust_best_rpy
    float   rpy_scale = 1.0f;           // this is used to scale the roll, pitch and yaw to fit within the motor limits
    float   actuator_allowed = 0.0f;    // amount of yaw we can fit in
    float   actuator[NUM_ACTUATORS];    // combined roll, pitch and yaw thrusts for each actuator
    float   actuator_max = 0.0f;        // maximum actuator value

    // apply voltage and air pressure compensation
    roll_thrust = _roll_in * get_compensation_gain();
    pitch_thrust = _pitch_in * get_compensation_gain();
    yaw_thrust = _yaw_in * get_compensation_gain();
    throttle_thrust = get_throttle() * get_compensation_gain();

    // sanity check throttle is above zero and below current limited throttle
    if (throttle_thrust <= 0.0f) {
        throttle_thrust = 0.0f;
            limit.throttle_lower = true;
        }
    // convert throttle_max from 0~1000 to 0~1 range
    if (throttle_thrust >= _throttle_thrust_max) {
        throttle_thrust = _throttle_thrust_max;
        limit.throttle_upper = true;
    }
    throttle_thrust_rpy_mix = MAX(throttle_thrust, throttle_thrust*MAX(0.0f,1.0f-_throttle_rpy_mix)+throttle_thrust_hover*_throttle_rpy_mix);

    // calculate how much roll and pitch must be scaled to leave enough range for the minimum yaw
    if (is_zero(MAX(roll_thrust, pitch_thrust))) {
        rpy_scale = 1.0f;
    } else {
        rpy_scale = (1.0f - MIN(yaw_thrust, (float)_yaw_headroom/1000.0f)) / MAX(roll_thrust, pitch_thrust);
    }
    if(rpy_scale < 1.0f){
        limit.roll_pitch = true;
    }else{
        rpy_scale = 1.0f;
    }
    actuator_allowed = 1.0f - rpy_scale * MAX((roll_thrust), (pitch_thrust));
    if(fabsf(yaw_thrust) > actuator_allowed){
        yaw_thrust = constrain_float(yaw_thrust, -actuator_allowed, actuator_allowed);
        limit.yaw = true;
    }

    // combine roll, pitch and yaw on each actuator
    // front servo
    actuator[0] = rpy_scale * roll_thrust + yaw_thrust;
    // right servo
    actuator[1] = rpy_scale * pitch_thrust + yaw_thrust;
    // rear servo
    actuator[2] = -rpy_scale * roll_thrust + yaw_thrust;
    // left servo
    actuator[3] = -rpy_scale * pitch_thrust + yaw_thrust;

    // calculate the minimum thrust that doesn't limit the roll, pitch and yaw forces
    thrust_min_rp = MAX(MAX((actuator[1]), (actuator[2])), MAX((actuator[3]), (actuator[4])));

    thr_adj = throttle_thrust - throttle_thrust_rpy_mix;
    if(thr_adj < -(throttle_thrust_rpy_mix - thrust_min_rp)){
        // Throttle can't be reduced to the desired level because this would mean roll or pitch control
        // would not be able to reach the desired level because of lack of thrust.
        thr_adj = -(throttle_thrust_rpy_mix - thrust_min_rp);
        limit.throttle_lower = true;
        if(thrust_min_rp > throttle_thrust_rpy_mix + thr_adj){
            // todo: add limits for roll and pitch separately
            limit.yaw = true;
            limit.roll_pitch = true;
        }
    }

    // calculate the throttle setting for the lift fan
    _thrust_out = throttle_thrust_rpy_mix + thr_adj;

    if(is_zero((throttle_thrust_rpy_mix + thr_adj))){
        limit.roll_pitch = true;
        limit.yaw = true;
        for (i=0; i<NUM_ACTUATORS; i++) {
            if(actuator[1] < 0.0f){
                _actuator_out[i] = -1.0f;
            }else if(actuator[i] > 0.0f){
                _actuator_out[i] = 1.0f;
            }else{
                _actuator_out[i] = 0.0f;
            }
        }
    }else{
        // calculate the maximum allowed actuator output and maximum requested actuator output
        actuator_allowed = (throttle_thrust_rpy_mix + thr_adj);
        for (i=0; i<NUM_ACTUATORS; i++) {
            if(actuator_max > (actuator[i])){
                actuator_max = (actuator[i]);
            }
        }
        if(actuator_max > actuator_allowed){
            // roll, pitch and yaw request can not be achieved at full servo defection
            // reduce roll, pitch and yaw to reduce the requested defection to maximum
            limit.roll_pitch = true;
            limit.yaw = true;
            rpy_scale = actuator_allowed/actuator_max;
        }else{
            rpy_scale = 1.0f;
        }
        // force of a lifting surface is approximately equal to the angle of attack times the airflow velocity squared
        // static thrust is proportional to the airflow velocity squared
        // therefore the torque of the roll and pitch actuators should be approximately proportional to
        // the angle of attack multiplied by the static thrust.
        for (i=0; i<NUM_ACTUATORS; i++) {
            if(actuator_max > (_actuator_out[i])){
                _actuator_out[i] = constrain_float(rpy_scale*actuator[i]/(throttle_thrust_rpy_mix + thr_adj), -1.0f, 1.0f);
            }
        }
    }
}

// output_test - spin a motor at the pwm value specified
//  motor_seq is the motor's sequence number from 1 to the number of motors on the frame
//  pwm value is an actual pwm value that will be output, normally in the range of 1000 ~ 2000
void AP_MotorsSingle::output_test(uint8_t motor_seq, int16_t pwm)
{
    // exit immediately if not armed
    if (!armed()) {
        return;
    }

    // output to motors and servos
    switch (motor_seq) {
        case 1:
            // flap servo 1
            rc_write(AP_MOTORS_MOT_1, pwm);
            break;
        case 2:
            // flap servo 2
            rc_write(AP_MOTORS_MOT_2, pwm);
            break;
        case 3:
            // flap servo 3
            rc_write(AP_MOTORS_MOT_3, pwm);
            break;
        case 4:
            // flap servo 4
            rc_write(AP_MOTORS_MOT_4, pwm);
            break;
        case 5:
            // spin motor 1
            rc_write(AP_MOTORS_MOT_5, pwm);
            break;
        case 6:
            // spin motor 2
            rc_write(AP_MOTORS_MOT_6, pwm);
            break;
        default:
            // do nothing
            break;
    }
}