ardupilot/libraries/AP_Motors/AP_MotorsTri.cpp

334 lines
13 KiB
C++

/*
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_MotorsTri.cpp - ArduCopter motors library
* Code by RandyMackay. DIYDrones.com
*
*/
#include <AP_HAL/AP_HAL.h>
#include <AP_Math/AP_Math.h>
#include <GCS_MAVLink/GCS.h>
#include "AP_MotorsTri.h"
extern const AP_HAL::HAL& hal;
// init
void AP_MotorsTri::init(motor_frame_class frame_class, motor_frame_type frame_type)
{
add_motor_num(AP_MOTORS_MOT_1);
add_motor_num(AP_MOTORS_MOT_2);
add_motor_num(AP_MOTORS_MOT_4);
// 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 ESCs can be calibrated like other frame types
motor_enabled[AP_MOTORS_MOT_1] = true;
motor_enabled[AP_MOTORS_MOT_2] = true;
motor_enabled[AP_MOTORS_MOT_4] = true;
// find the yaw servo
_yaw_servo = SRV_Channels::get_channel_for(SRV_Channel::k_motor7, AP_MOTORS_CH_TRI_YAW);
if (!_yaw_servo) {
gcs().send_text(MAV_SEVERITY_ERROR, "MotorsTri: unable to setup yaw channel");
// don't set initialised_ok
return;
}
// allow mapping of motor7
add_motor_num(AP_MOTORS_CH_TRI_YAW);
// record successful initialisation if what we setup was the desired frame_class
_flags.initialised_ok = (frame_class == MOTOR_FRAME_TRI);
}
// set frame class (i.e. quad, hexa, heli) and type (i.e. x, plus)
void AP_MotorsTri::set_frame_class_and_type(motor_frame_class frame_class, motor_frame_type frame_type)
{
_flags.initialised_ok = (frame_class == MOTOR_FRAME_TRI);
}
// set update rate to motors - a value in hertz
void AP_MotorsTri::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_4;
rc_set_freq(mask, _speed_hz);
}
void AP_MotorsTri::output_to_motors()
{
switch (_spool_mode) {
case SHUT_DOWN:
// sends minimum values out to the motors
rc_write(AP_MOTORS_MOT_1, get_pwm_output_min());
rc_write(AP_MOTORS_MOT_2, get_pwm_output_min());
rc_write(AP_MOTORS_MOT_4, get_pwm_output_min());
rc_write(AP_MOTORS_CH_TRI_YAW, _yaw_servo->get_trim());
break;
case SPIN_WHEN_ARMED:
// sends output to motors when armed but not flying
rc_write(AP_MOTORS_MOT_1, calc_spin_up_to_pwm());
rc_write(AP_MOTORS_MOT_2, calc_spin_up_to_pwm());
rc_write(AP_MOTORS_MOT_4, calc_spin_up_to_pwm());
rc_write(AP_MOTORS_CH_TRI_YAW, _yaw_servo->get_trim());
break;
case SPOOL_UP:
case THROTTLE_UNLIMITED:
case SPOOL_DOWN:
// set motor output based on thrust requests
rc_write(AP_MOTORS_MOT_1, calc_thrust_to_pwm(_thrust_right));
rc_write(AP_MOTORS_MOT_2, calc_thrust_to_pwm(_thrust_left));
rc_write(AP_MOTORS_MOT_4, calc_thrust_to_pwm(_thrust_rear));
rc_write(AP_MOTORS_CH_TRI_YAW, calc_yaw_radio_output(_pivot_angle, radians(_yaw_servo_angle_max_deg)));
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_MotorsTri::get_motor_mask()
{
// tri copter uses channels 1,2,4 and 7
uint16_t motor_mask = (1U << AP_MOTORS_MOT_1) |
(1U << AP_MOTORS_MOT_2) |
(1U << AP_MOTORS_MOT_4) |
(1U << AP_MOTORS_CH_TRI_YAW);
uint16_t mask = rc_map_mask(motor_mask);
// add parent's mask
mask |= AP_MotorsMulticopter::get_motor_mask();
return mask;
}
// output_armed - sends commands to the motors
// includes new scaling stability patch
void AP_MotorsTri::output_armed_stabilizing()
{
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 throttle_avg_max; // throttle thrust average maximum value, 0.0 - 1.0
float throttle_thrust_best_rpy; // throttle providing maximum roll, pitch and yaw range without climbing
float rpy_scale = 1.0f; // this is used to scale the roll, pitch and yaw to fit within the motor limits
float rpy_low = 0.0f; // lowest motor value
float rpy_high = 0.0f; // highest motor value
float thr_adj; // the difference between the pilot's desired throttle and throttle_thrust_best_rpy
// sanity check YAW_SV_ANGLE parameter value to avoid divide by zero
_yaw_servo_angle_max_deg = constrain_float(_yaw_servo_angle_max_deg, AP_MOTORS_TRI_SERVO_RANGE_DEG_MIN, AP_MOTORS_TRI_SERVO_RANGE_DEG_MAX);
// apply voltage and air pressure compensation
const float compensation_gain = get_compensation_gain();
roll_thrust = _roll_in * compensation_gain;
pitch_thrust = _pitch_in * compensation_gain;
yaw_thrust = _yaw_in * compensation_gain * sinf(radians(_yaw_servo_angle_max_deg)); // we scale this so a thrust request of 1.0f will ask for full servo deflection at full rear throttle
throttle_thrust = get_throttle() * compensation_gain;
throttle_avg_max = _throttle_avg_max * compensation_gain;
// calculate angle of yaw pivot
_pivot_angle = safe_asin(yaw_thrust);
if (fabsf(_pivot_angle) > radians(_yaw_servo_angle_max_deg)) {
limit.yaw = true;
_pivot_angle = constrain_float(_pivot_angle, -radians(_yaw_servo_angle_max_deg), radians(_yaw_servo_angle_max_deg));
}
float pivot_thrust_max = cosf(_pivot_angle);
float thrust_max = 1.0f;
// sanity check throttle is above zero and below current limited throttle
if (throttle_thrust <= 0.0f) {
throttle_thrust = 0.0f;
limit.throttle_lower = true;
}
if (throttle_thrust >= _throttle_thrust_max) {
throttle_thrust = _throttle_thrust_max;
limit.throttle_upper = true;
}
throttle_avg_max = constrain_float(throttle_avg_max, throttle_thrust, _throttle_thrust_max);
// The following mix may be offer less coupling between axis but needs testing
//_thrust_right = roll_thrust * -0.5f + pitch_thrust * 1.0f;
//_thrust_left = roll_thrust * 0.5f + pitch_thrust * 1.0f;
//_thrust_rear = 0;
_thrust_right = roll_thrust * -0.5f + pitch_thrust * 0.5f;
_thrust_left = roll_thrust * 0.5f + pitch_thrust * 0.5f;
_thrust_rear = pitch_thrust * -0.5f;
// calculate roll and pitch for each motor
// set rpy_low and rpy_high to the lowest and highest values of the motors
// record lowest roll pitch command
rpy_low = MIN(_thrust_right,_thrust_left);
rpy_high = MAX(_thrust_right,_thrust_left);
if (rpy_low > _thrust_rear){
rpy_low = _thrust_rear;
}
// check to see if the rear motor will reach maximum thrust before the front two motors
if ((1.0f - rpy_high) > (pivot_thrust_max - _thrust_rear)){
thrust_max = pivot_thrust_max;
rpy_high = _thrust_rear;
}
// calculate throttle that gives most possible room for yaw (range 1000 ~ 2000) which is the lower of:
// 1. 0.5f - (rpy_low+rpy_high)/2.0 - this would give the maximum possible room margin above the highest motor and below the lowest
// 2. the higher of:
// a) the pilot's throttle input
// b) the point _throttle_rpy_mix between the pilot's input throttle and hover-throttle
// Situation #2 ensure we never increase the throttle above hover throttle unless the pilot has commanded this.
// Situation #2b allows us to raise the throttle above what the pilot commanded but not so far that it would actually cause the copter to rise.
// We will choose #1 (the best throttle for yaw control) if that means reducing throttle to the motors (i.e. we favor reducing throttle *because* it provides better yaw control)
// We will choose #2 (a mix of pilot and hover throttle) only when the throttle is quite low. We favor reducing throttle instead of better yaw control because the pilot has commanded it
// check everything fits
throttle_thrust_best_rpy = MIN(0.5f*thrust_max - (rpy_low+rpy_high)/2.0, throttle_avg_max);
if(is_zero(rpy_low)){
rpy_scale = 1.0f;
} else {
rpy_scale = constrain_float(-throttle_thrust_best_rpy/rpy_low, 0.0f, 1.0f);
}
// calculate how close the motors can come to the desired throttle
thr_adj = throttle_thrust - throttle_thrust_best_rpy;
if(rpy_scale < 1.0f){
// Full range is being used by roll, pitch, and yaw.
limit.roll_pitch = true;
if (thr_adj > 0.0f){
limit.throttle_upper = true;
}
thr_adj = 0.0f;
}else{
if(thr_adj < -(throttle_thrust_best_rpy+rpy_low)){
// Throttle can't be reduced to desired value
thr_adj = -(throttle_thrust_best_rpy+rpy_low);
}else if(thr_adj > thrust_max - (throttle_thrust_best_rpy+rpy_high)){
// Throttle can't be increased to desired value
thr_adj = thrust_max - (throttle_thrust_best_rpy+rpy_high);
limit.throttle_upper = true;
}
}
// add scaled roll, pitch, constrained yaw and throttle for each motor
_thrust_right = throttle_thrust_best_rpy+thr_adj + rpy_scale*_thrust_right;
_thrust_left = throttle_thrust_best_rpy+thr_adj + rpy_scale*_thrust_left;
_thrust_rear = throttle_thrust_best_rpy+thr_adj + rpy_scale*_thrust_rear;
// scale pivot thrust to account for pivot angle
// we should not need to check for divide by zero as _pivot_angle is constrained to the 5deg ~ 80 deg range
_thrust_rear = _thrust_rear/cosf(_pivot_angle);
// constrain all outputs to 0.0f to 1.0f
// test code should be run with these lines commented out as they should not do anything
_thrust_right = constrain_float(_thrust_right, 0.0f, 1.0f);
_thrust_left = constrain_float(_thrust_left, 0.0f, 1.0f);
_thrust_rear = constrain_float(_thrust_rear, 0.0f, 1.0f);
}
// output_test_seq - 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_MotorsTri::output_test_seq(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:
// front right motor
rc_write(AP_MOTORS_MOT_1, pwm);
break;
case 2:
// back motor
rc_write(AP_MOTORS_MOT_4, pwm);
break;
case 3:
// back servo
rc_write(AP_MOTORS_CH_TRI_YAW, pwm);
break;
case 4:
// front left motor
rc_write(AP_MOTORS_MOT_2, pwm);
break;
default:
// do nothing
break;
}
}
// calc_yaw_radio_output - calculate final radio output for yaw channel
int16_t AP_MotorsTri::calc_yaw_radio_output(float yaw_input, float yaw_input_max)
{
int16_t ret;
if (_yaw_servo->get_reversed()) {
yaw_input = -yaw_input;
}
if (yaw_input >= 0){
ret = (_yaw_servo->get_trim() + (yaw_input/yaw_input_max * (_yaw_servo->get_output_max() - _yaw_servo->get_trim())));
} else {
ret = (_yaw_servo->get_trim() + (yaw_input/yaw_input_max * (_yaw_servo->get_trim() - _yaw_servo->get_output_min())));
}
return ret;
}
/*
call vehicle supplied thrust compensation if set. This allows for
vehicle specific thrust compensation for motor arrangements such as
the forward motors tilting
*/
void AP_MotorsTri::thrust_compensation(void)
{
if (_thrust_compensation_callback) {
// convert 3 thrust values into an array indexed by motor number
float thrust[4] { _thrust_right, _thrust_left, 0, _thrust_rear };
// apply vehicle supplied compensation function
_thrust_compensation_callback(thrust, 4);
// extract compensated thrust values
_thrust_right = thrust[0];
_thrust_left = thrust[1];
_thrust_rear = thrust[3];
}
}
/*
override tricopter tail servo output in output_motor_mask
*/
void AP_MotorsTri::output_motor_mask(float thrust, uint8_t mask)
{
// normal multicopter output
AP_MotorsMulticopter::output_motor_mask(thrust, mask);
// and override yaw servo
rc_write(AP_MOTORS_CH_TRI_YAW, _yaw_servo->get_trim());
}