mirror of https://github.com/ArduPilot/ardupilot
392 lines
15 KiB
C++
392 lines
15 KiB
C++
// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* AP_MotorsMulticopter.cpp - ArduCopter multicopter motors library
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* Code by Randy Mackay and Robert Lefebvre. DIYDrones.com
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*
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*/
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#include "AP_MotorsMulticopter.h"
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#include <AP_HAL/AP_HAL.h>
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extern const AP_HAL::HAL& hal;
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// parameters for the motor class
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const AP_Param::GroupInfo AP_MotorsMulticopter::var_info[] = {
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// 0 was used by TB_RATIO
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// 1,2,3 were used by throttle curve
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// @Param: SPIN_ARMED
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// @DisplayName: Motors always spin when armed
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// @Description: Controls whether motors always spin when armed (must be below THR_MIN)
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// @Values: 0:Do Not Spin,70:VerySlow,100:Slow,130:Medium,150:Fast
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// @User: Standard
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AP_GROUPINFO("SPIN_ARMED", 5, AP_MotorsMulticopter, _spin_when_armed, AP_MOTORS_SPIN_WHEN_ARMED),
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// @Param: YAW_HEADROOM
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// @DisplayName: Matrix Yaw Min
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// @Description: Yaw control is given at least this pwm range
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// @Range: 0 500
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// @Units: pwm
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// @User: Advanced
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AP_GROUPINFO("YAW_HEADROOM", 6, AP_MotorsMulticopter, _yaw_headroom, AP_MOTORS_YAW_HEADROOM_DEFAULT),
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// 7 was THR_LOW_CMP
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// @Param: THST_EXPO
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// @DisplayName: Thrust Curve Expo
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// @Description: Motor thrust curve exponent (from 0 for linear to 1.0 for second order curve)
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// @Range: 0.25 0.8
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// @User: Advanced
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AP_GROUPINFO("THST_EXPO", 8, AP_MotorsMulticopter, _thrust_curve_expo, AP_MOTORS_THST_EXPO_DEFAULT),
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// @Param: THST_MAX
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// @DisplayName: Thrust Curve Max
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// @Description: Point at which the thrust saturates
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// @Values: 0.9:Low, 1.0:High
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// @User: Advanced
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AP_GROUPINFO("THST_MAX", 9, AP_MotorsMulticopter, _thrust_curve_max, AP_MOTORS_THST_MAX_DEFAULT),
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// @Param: THST_BAT_MAX
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// @DisplayName: Battery voltage compensation maximum voltage
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// @Description: Battery voltage compensation maximum voltage (voltage above this will have no additional scaling effect on thrust). Recommend 4.4 * cell count, 0 = Disabled
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// @Range: 6 35
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// @Units: Volts
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// @User: Advanced
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AP_GROUPINFO("THST_BAT_MAX", 10, AP_MotorsMulticopter, _batt_voltage_max, AP_MOTORS_THST_BAT_MAX_DEFAULT),
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// @Param: THST_BAT_MIN
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// @DisplayName: Battery voltage compensation minimum voltage
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// @Description: Battery voltage compensation minimum voltage (voltage below this will have no additional scaling effect on thrust). Recommend 3.5 * cell count, 0 = Disabled
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// @Range: 6 35
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// @Units: Volts
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// @User: Advanced
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AP_GROUPINFO("THST_BAT_MIN", 11, AP_MotorsMulticopter, _batt_voltage_min, AP_MOTORS_THST_BAT_MIN_DEFAULT),
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// @Param: CURR_MAX
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// @DisplayName: Motor Current Max
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// @Description: Maximum current over which maximum throttle is limited (0 = Disabled)
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// @Range: 0 200
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// @Units: Amps
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// @User: Advanced
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AP_GROUPINFO("CURR_MAX", 12, AP_MotorsMulticopter, _batt_current_max, AP_MOTORS_CURR_MAX_DEFAULT),
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// @Param: THR_MIX_MIN
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// @DisplayName: Throttle Mix Minimum
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// @Description: Throttle vs attitude control prioritisation used when landing (higher values mean we prioritise attitude control over throttle)
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// @Range: 0.1 0.25
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// @User: Advanced
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AP_GROUPINFO("THR_MIX_MIN", 13, AP_MotorsMulticopter, _thr_mix_min, AP_MOTORS_THR_MIX_MIN_DEFAULT),
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// @Param: THR_MIX_MAX
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// @DisplayName: Throttle Mix Maximum
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// @Description: Throttle vs attitude control prioritisation used during active flight (higher values mean we prioritise attitude control over throttle)
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// @Range: 0.5 0.9
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// @User: Advanced
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AP_GROUPINFO("THR_MIX_MAX", 14, AP_MotorsMulticopter, _thr_mix_max, AP_MOTORS_THR_MIX_MAX_DEFAULT),
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AP_GROUPEND
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};
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// Constructor
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AP_MotorsMulticopter::AP_MotorsMulticopter(uint16_t loop_rate, uint16_t speed_hz) :
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AP_Motors(loop_rate, speed_hz),
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_spin_when_armed_ramped(0),
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_throttle_thr_mix_desired(AP_MOTORS_THR_LOW_CMP_DEFAULT),
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_throttle_thr_mix(AP_MOTORS_THR_LOW_CMP_DEFAULT),
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_min_throttle(AP_MOTORS_DEFAULT_MIN_THROTTLE),
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_max_throttle(AP_MOTORS_DEFAULT_MAX_THROTTLE),
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_hover_out(AP_MOTORS_DEFAULT_MID_THROTTLE),
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_batt_voltage_resting(0.0f),
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_batt_current_resting(0.0f),
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_batt_resistance(0.0f),
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_batt_timer(0),
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_lift_max(1.0f),
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_throttle_limit(1.0f)
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{
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AP_Param::setup_object_defaults(this, var_info);
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// disable all motors by default
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memset(motor_enabled, false, sizeof(motor_enabled));
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// init flags
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_multicopter_flags.slow_start = false;
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_multicopter_flags.slow_start_low_end = true;
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// setup battery voltage filtering
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_batt_voltage_filt.set_cutoff_frequency(AP_MOTORS_BATT_VOLT_FILT_HZ);
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_batt_voltage_filt.reset(1.0f);
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};
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// output - sends commands to the motors
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void AP_MotorsMulticopter::output()
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{
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// update throttle filter
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update_throttle_filter();
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// update max throttle
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update_max_throttle();
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// update battery resistance
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update_battery_resistance();
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// calc filtered battery voltage and lift_max
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update_lift_max_from_batt_voltage();
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// move throttle_low_comp towards desired throttle low comp
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update_throttle_thr_mix();
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if (_flags.armed) {
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if (!_flags.interlock) {
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output_armed_zero_throttle();
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} else if (_flags.stabilizing) {
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output_armed_stabilizing();
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} else {
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output_armed_not_stabilizing();
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}
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} else {
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_multicopter_flags.slow_start_low_end = true;
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output_disarmed();
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}
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};
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// update the throttle input filter
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void AP_MotorsMulticopter::update_throttle_filter()
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{
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if (armed()) {
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_throttle_filter.apply(_throttle_in, 1.0f/_loop_rate);
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} else {
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_throttle_filter.reset(0.0f);
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}
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// constrain throttle signal to 0-1000
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_throttle_control_input = constrain_float(_throttle_filter.get(),0.0f,1000.0f);
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}
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// update_max_throttle - updates the limits on _max_throttle if necessary taking into account slow_start_throttle flag
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void AP_MotorsMulticopter::update_max_throttle()
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{
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// ramp up minimum spin speed if necessary
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if (_multicopter_flags.slow_start_low_end) {
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_spin_when_armed_ramped += AP_MOTOR_SLOW_START_LOW_END_INCREMENT;
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if (_spin_when_armed_ramped >= _spin_when_armed) {
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_spin_when_armed_ramped = _spin_when_armed;
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_multicopter_flags.slow_start_low_end = false;
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}
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}
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// implement slow start
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if (_multicopter_flags.slow_start) {
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// increase slow start throttle
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_max_throttle += AP_MOTOR_SLOW_START_INCREMENT;
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// turn off slow start if we've reached max throttle
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if (_max_throttle >= _throttle_control_input) {
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_max_throttle = AP_MOTORS_DEFAULT_MAX_THROTTLE;
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_multicopter_flags.slow_start = false;
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}
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return;
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}
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// current limit throttle
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current_limit_max_throttle();
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}
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// current_limit_max_throttle - limits maximum throttle based on current
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void AP_MotorsMulticopter::current_limit_max_throttle()
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{
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// return maximum if current limiting is disabled
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if (_batt_current_max <= 0) {
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_throttle_limit = 1.0f;
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_max_throttle = AP_MOTORS_DEFAULT_MAX_THROTTLE;
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return;
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}
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// remove throttle limit if throttle is at zero or disarmed
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if(_throttle_control_input <= 0 || !_flags.armed) {
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_throttle_limit = 1.0f;
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}
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// limit throttle if over current
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if (_batt_current > _batt_current_max*1.25f) {
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// Fast drop for extreme over current (1 second)
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_throttle_limit -= 1.0f/_loop_rate;
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} else if(_batt_current > _batt_current_max) {
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// Slow drop for extreme over current (5 second)
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_throttle_limit -= 0.2f/_loop_rate;
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} else {
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// Increase throttle limit (2 second)
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_throttle_limit += 0.5f/_loop_rate;
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}
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// throttle limit drops to 20% between hover and full throttle
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_throttle_limit = constrain_float(_throttle_limit, 0.2f, 1.0f);
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// limit max throttle
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_max_throttle = _hover_out + ((1000-_hover_out)*_throttle_limit);
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}
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// apply_thrust_curve_and_volt_scaling - returns throttle curve adjusted pwm value (i.e. 1000 ~ 2000)
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int16_t AP_MotorsMulticopter::apply_thrust_curve_and_volt_scaling(int16_t pwm_out, int16_t pwm_min, int16_t pwm_max) const
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{
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// convert to 0.0 to 1.0 ratio
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float throttle_ratio = ((float)(pwm_out-pwm_min))/((float)(pwm_max-pwm_min));
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// apply thrust curve - domain 0.0 to 1.0, range 0.0 to 1.0
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if (_thrust_curve_expo > 0.0f){
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throttle_ratio = ((_thrust_curve_expo-1.0f) + safe_sqrt((1.0f-_thrust_curve_expo)*(1.0f-_thrust_curve_expo) + 4.0f*_thrust_curve_expo*_lift_max*throttle_ratio))/(2.0f*_thrust_curve_expo*_batt_voltage_filt.get());
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}
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// scale to maximum thrust point
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throttle_ratio *= _thrust_curve_max;
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// convert back to pwm range, constrain and return
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return (int16_t)constrain_float(throttle_ratio*(pwm_max-pwm_min)+pwm_min, pwm_min, (pwm_max-pwm_min)*_thrust_curve_max+pwm_min);
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}
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// update_lift_max from battery voltage - used for voltage compensation
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void AP_MotorsMulticopter::update_lift_max_from_batt_voltage()
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{
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// sanity check battery_voltage_min is not too small
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// if disabled or misconfigured exit immediately
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if((_batt_voltage_max <= 0) || (_batt_voltage_min >= _batt_voltage_max) || (_batt_voltage < 0.25f*_batt_voltage_min)) {
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_batt_voltage_filt.reset(1.0f);
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_lift_max = 1.0f;
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return;
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}
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_batt_voltage_min = MAX(_batt_voltage_min, _batt_voltage_max * 0.6f);
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// add current based voltage sag to battery voltage
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float batt_voltage = _batt_voltage + _batt_current * _batt_resistance;
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batt_voltage = constrain_float(batt_voltage, _batt_voltage_min, _batt_voltage_max);
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// filter at 0.5 Hz
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float bvf = _batt_voltage_filt.apply(batt_voltage/_batt_voltage_max, 1.0f/_loop_rate);
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// calculate lift max
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_lift_max = bvf*(1-_thrust_curve_expo) + _thrust_curve_expo*bvf*bvf;
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}
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// update_battery_resistance - calculate battery resistance when throttle is above hover_out
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void AP_MotorsMulticopter::update_battery_resistance()
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{
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// if motors are stopped, reset resting voltage and current
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if (_throttle_control_input <= 0 || !_flags.armed) {
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_batt_voltage_resting = _batt_voltage;
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_batt_current_resting = _batt_current;
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_batt_timer = 0;
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} else {
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// update battery resistance when throttle is over hover throttle
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if ((_batt_timer < 400) && ((_batt_current_resting*2.0f) < _batt_current)) {
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if (_throttle_control_input >= _hover_out) {
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// filter reaches 90% in 1/4 the test time
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_batt_resistance += 0.05f*(( (_batt_voltage_resting-_batt_voltage)/(_batt_current-_batt_current_resting) ) - _batt_resistance);
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_batt_timer += 1;
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} else {
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// initialize battery resistance to prevent change in resting voltage estimate
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_batt_resistance = ((_batt_voltage_resting-_batt_voltage)/(_batt_current-_batt_current_resting));
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}
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}
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}
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}
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// update_throttle_thr_mix - slew set_throttle_thr_mix to requested value
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void AP_MotorsMulticopter::update_throttle_thr_mix()
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{
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// slew _throttle_thr_mix to _throttle_thr_mix_desired
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if (_throttle_thr_mix < _throttle_thr_mix_desired) {
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// increase quickly (i.e. from 0.1 to 0.9 in 0.4 seconds)
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_throttle_thr_mix += MIN(2.0f/_loop_rate, _throttle_thr_mix_desired-_throttle_thr_mix);
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} else if (_throttle_thr_mix > _throttle_thr_mix_desired) {
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// reduce more slowly (from 0.9 to 0.1 in 1.6 seconds)
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_throttle_thr_mix -= MIN(0.5f/_loop_rate, _throttle_thr_mix-_throttle_thr_mix_desired);
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}
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_throttle_thr_mix = constrain_float(_throttle_thr_mix, 0.1f, 1.0f);
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}
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// get_hover_throttle_as_pwm - converts hover throttle to pwm (i.e. range 1000 ~ 2000)
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int16_t AP_MotorsMulticopter::get_hover_throttle_as_pwm() const
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{
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return (_throttle_radio_min + (float)(_throttle_radio_max - _throttle_radio_min) * _hover_out / 1000.0f);
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}
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float AP_MotorsMulticopter::get_compensation_gain() const
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{
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// avoid divide by zero
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if (_lift_max <= 0.0f) {
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return 1.0f;
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}
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float ret = 1.0f / _lift_max;
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#if AP_MOTORS_DENSITY_COMP == 1
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// air density ratio is increasing in density / decreasing in altitude
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if (_air_density_ratio > 0.3f && _air_density_ratio < 1.5f) {
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ret *= 1.0f / constrain_float(_air_density_ratio,0.5f,1.25f);
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}
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#endif
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return ret;
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}
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float AP_MotorsMulticopter::rel_pwm_to_thr_range(float pwm) const
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{
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return pwm/_throttle_pwm_scalar;
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}
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float AP_MotorsMulticopter::thr_range_to_rel_pwm(float thr) const
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{
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return _throttle_pwm_scalar*thr;
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}
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// set_throttle_range - sets the minimum throttle that will be sent to the engines when they're not off (i.e. to prevents issues with some motors spinning and some not at very low throttle)
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// also sets throttle channel minimum and maximum pwm
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void AP_MotorsMulticopter::set_throttle_range(uint16_t min_throttle, int16_t radio_min, int16_t radio_max)
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{
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_throttle_radio_min = radio_min;
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_throttle_radio_max = radio_max;
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_throttle_pwm_scalar = (_throttle_radio_max - _throttle_radio_min) / 1000.0f;
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_rpy_pwm_scalar = (_throttle_radio_max - (_throttle_radio_min + _min_throttle)) / 9000.0f;
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_min_throttle = (float)min_throttle * _throttle_pwm_scalar;
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}
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// slow_start - set to true to slew motors from current speed to maximum
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// Note: this must be set immediately before a step up in throttle
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void AP_MotorsMulticopter::slow_start(bool true_false)
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{
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// set slow_start flag
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_multicopter_flags.slow_start = true;
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// initialise maximum throttle to current throttle
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_max_throttle = constrain_int16(_throttle_control_input, 0, AP_MOTORS_DEFAULT_MAX_THROTTLE);
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}
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// throttle_pass_through - passes provided pwm directly to all motors - dangerous but used for initialising ESCs
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// pwm value is an actual pwm value that will be output, normally in the range of 1000 ~ 2000
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void AP_MotorsMulticopter::throttle_pass_through(int16_t pwm)
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{
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if (armed()) {
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// send the pilot's input directly to each enabled motor
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hal.rcout->cork();
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for (uint16_t i=0; i < AP_MOTORS_MAX_NUM_MOTORS; i++) {
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if (motor_enabled[i]) {
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rc_write(i, pwm);
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}
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}
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hal.rcout->push();
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}
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}
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