ardupilot/libraries/AP_Motors/AP_MotorsMulticopter.h

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// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
/// @file AP_MotorsMulticopter.h
/// @brief Motor control class for Multicopters
#ifndef __AP_MOTORS_MULTICOPTER_H__
#define __AP_MOTORS_MULTICOPTER_H__
#include "AP_Motors_Class.h"
#define AP_MOTORS_DEFAULT_MIN_THROTTLE 130
#define AP_MOTORS_DEFAULT_MID_THROTTLE 500
#define AP_MOTORS_DEFAULT_MAX_THROTTLE 1000
#define AP_MOTORS_SPIN_WHEN_ARMED 70 // spin motors at this PWM value when armed
#define AP_MOTORS_YAW_HEADROOM_DEFAULT 200
#define AP_MOTORS_THR_LOW_CMP_DEFAULT 0.5f // ratio controlling the max throttle output during competing requests of low throttle from the pilot (or autopilot) and higher throttle for attitude control. Higher favours Attitude over pilot input
#define AP_MOTORS_THST_EXPO_DEFAULT 0.65f // set to 0 for linear and 1 for second order approximation
#define AP_MOTORS_THST_MAX_DEFAULT 0.95f // throttle which produces the maximum thrust. (i.e. 0 ~ 1 ) of the full throttle range
#define AP_MOTORS_THST_BAT_MAX_DEFAULT 0.0f
#define AP_MOTORS_THST_BAT_MIN_DEFAULT 0.0f
#define AP_MOTORS_CURR_MAX_DEFAULT 0.0f // current limiting max default
#define AP_MOTORS_BATT_VOLT_FILT_HZ 0.5f // battery voltage filtered at 0.5hz
#define AP_MOTORS_THR_MIX_MIN_DEFAULT 0.1f // minimum throttle mix
#define AP_MOTORS_THR_MIX_MID_DEFAULT 0.5f // manual throttle mix
#define AP_MOTORS_THR_MIX_MAX_DEFAULT 0.5f // maximum throttle mix default
// To-Do: replace this hard coded counter with a timer
#if HAL_CPU_CLASS < HAL_CPU_CLASS_75 || CONFIG_HAL_BOARD == HAL_BOARD_SITL || CONFIG_HAL_BOARD == HAL_BOARD_LINUX
// slow start increments - throttle increase per (100hz) iteration. i.e. 5 = full speed in 2 seconds
#define AP_MOTOR_SLOW_START_INCREMENT 10 // max throttle ramp speed (i.e. motors can reach full throttle in 1 second)
#define AP_MOTOR_SLOW_START_LOW_END_INCREMENT 2 // min throttle ramp speed (i.e. motors will speed up from zero to _spin_when_armed speed in about 1 second)
#else
// slow start increments - throttle increase per (400hz) iteration. i.e. 1 = full speed in 2.5 seconds
#define AP_MOTOR_SLOW_START_INCREMENT 3 // max throttle ramp speed (i.e. motors can reach full throttle in 0.8 seconds)
#define AP_MOTOR_SLOW_START_LOW_END_INCREMENT 1 // min throttle ramp speed (i.e. motors will speed up from zero to _spin_when_armed speed in about 0.3 second)
#endif
/// @class AP_MotorsMulticopter
class AP_MotorsMulticopter : public AP_Motors {
public:
// Constructor
AP_MotorsMulticopter(uint16_t loop_rate, uint16_t speed_hz = AP_MOTORS_SPEED_DEFAULT);
// output - sends commands to the motors
virtual void output();
// set_yaw_headroom - set yaw headroom (yaw is given at least this amount of pwm)
void set_yaw_headroom(int16_t pwm) { _yaw_headroom = pwm; }
// set_throttle_thr_mix - set desired throttle_thr_mix (actual throttle_thr_mix is slewed towards this value over 1~2 seconds)
// low values favour pilot/autopilot throttle over attitude control, high values favour attitude control over throttle
// has no effect when throttle is above hover throttle
void set_throttle_mix_min() { _throttle_thr_mix_desired = _thr_mix_min; }
void set_throttle_mix_mid() { _throttle_thr_mix_desired = AP_MOTORS_THR_MIX_MID_DEFAULT; }
void set_throttle_mix_max() { _throttle_thr_mix_desired = _thr_mix_max; }
// get_throttle_thr_mix - get low throttle compensation value
bool is_throttle_mix_min() const { return (_throttle_thr_mix < 1.25f*_thr_mix_min); }
// returns warning throttle
float get_throttle_warn() const { return rel_pwm_to_thr_range(_spin_when_armed); }
int16_t throttle_min() const { return rel_pwm_to_thr_range(_min_throttle); }
// 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)
// also sets throttle channel minimum and maximum pwm
void set_throttle_range(uint16_t min_throttle, int16_t radio_min, int16_t radio_max);
// set_hover_throttle - sets the mid throttle which is close to the hover throttle of the copter
// this is used to limit the amount that the stability patch will increase the throttle to give more room for roll, pitch and yaw control
void set_hover_throttle(uint16_t hov_thr) { _hover_out = hov_thr; }
// slow_start - set to true to slew motors from current speed to maximum
// Note: this must be set immediately before a step up in throttle
void slow_start(bool true_false);
// throttle_pass_through - passes provided pwm directly to all motors - dangerous but used for initialising ESCs
// pwm value is an actual pwm value that will be output, normally in the range of 1000 ~ 2000
void throttle_pass_through(int16_t pwm);
// get_lift_max - get maximum lift ratio - for logging purposes only
float get_lift_max() { return _lift_max; }
// get_batt_voltage_filt - get battery voltage ratio - for logging purposes only
float get_batt_voltage_filt() const { return _batt_voltage_filt.get(); }
// get_batt_resistance - get battery resistance approximation - for logging purposes only
float get_batt_resistance() const { return _batt_resistance; }
// get_throttle_limit - throttle limit ratio - for logging purposes only
float get_throttle_limit() const { return _throttle_limit; }
// var_info for holding Parameter information
static const struct AP_Param::GroupInfo var_info[];
protected:
// update the throttle input filter
virtual void update_throttle_filter();
// update_max_throttle - updates the limits on _max_throttle for slow_start and current limiting flag
void update_max_throttle();
// current_limit_max_throttle - current limit maximum throttle (called from update_max_throttle)
void current_limit_max_throttle();
// apply_thrust_curve_and_volt_scaling - thrust curve and voltage adjusted pwm value (i.e. 1000 ~ 2000)
int16_t apply_thrust_curve_and_volt_scaling(int16_t pwm_out, int16_t pwm_min, int16_t pwm_max) const;
// update_lift_max_from_batt_voltage - used for voltage compensation
void update_lift_max_from_batt_voltage();
// update_battery_resistance - calculate battery resistance when throttle is above hover_out
void update_battery_resistance();
// update_throttle_thr_mix - updates thr_low_comp value towards the target
void update_throttle_thr_mix();
// return gain scheduling gain based on voltage and air density
float get_compensation_gain() const;
// get_hover_throttle_as_pwm - converts hover throttle to pwm (i.e. range 1000 ~ 2000)
int16_t get_hover_throttle_as_pwm() const;
float rel_pwm_to_thr_range(float pwm) const;
float thr_range_to_rel_pwm(float thr) const;
// convert RPY and Throttle servo ranges from legacy controller scheme back into PWM values
// RPY channels typically +/-45 degrees servo travel between +/-400 PWM
// Throttle channel typically 0-1000 range converts to 1100-1900 PWM for final output signal to motors
// ToDo: this should all be handled as floats +/- 1.0 instead of PWM and fake angle ranges
float calc_roll_pwm() { return (_roll_control_input * _rpy_pwm_scalar); }
float calc_pitch_pwm() { return (_pitch_control_input * _rpy_pwm_scalar); }
float calc_yaw_pwm() { return (_yaw_control_input * _rpy_pwm_scalar); }
int16_t calc_throttle_radio_output() { return (_throttle_control_input * _throttle_pwm_scalar) + _throttle_radio_min;}
// flag bitmask
struct {
uint8_t slow_start : 1; // 1 if slow start is active
uint8_t slow_start_low_end : 1; // 1 just after arming so we can ramp up the spin_when_armed value
} _multicopter_flags;
// parameters
AP_Int16 _spin_when_armed; // used to control whether the motors always spin when armed. pwm value above radio_min
AP_Int16 _yaw_headroom; // yaw control is given at least this pwm range
AP_Float _thrust_curve_expo; // curve used to linearize pwm to thrust conversion. set to 0 for linear and 1 for second order approximation
AP_Float _thrust_curve_max; // throttle which produces the maximum thrust. (i.e. 0 ~ 1 ) of the full throttle range
AP_Float _batt_voltage_max; // maximum voltage used to scale lift
AP_Float _batt_voltage_min; // minimum voltage used to scale lift
AP_Float _batt_current_max; // current over which maximum throttle is limited
AP_Float _thr_mix_min; // throttle vs attitude control prioritisation used when landing (higher values mean we prioritise attitude control over throttle)
AP_Float _thr_mix_max; // throttle vs attitude control prioritisation used during active flight (higher values mean we prioritise attitude control over throttle)
// internal variables
bool motor_enabled[AP_MOTORS_MAX_NUM_MOTORS]; // true if motor is enabled
int16_t _spin_when_armed_ramped; // equal to _spin_when_armed parameter but slowly ramped up from zero
float _throttle_thr_mix_desired; // desired throttle_low_comp value, actual throttle_low_comp is slewed towards this value over 1~2 seconds
float _throttle_thr_mix; // mix between throttle and hover throttle for 0 to 1 and ratio above hover throttle for >1
int16_t _min_throttle; // the minimum throttle to be sent to the motors when they're on (prevents motors stalling while flying)
int16_t _max_throttle; // the maximum throttle to be sent to the motors (sometimes limited by slow start)
int16_t _hover_out; // the estimated hover throttle as pct * 10 (i.e. 0 ~ 1000)
// battery voltage, current and air pressure compensation variables
float _batt_voltage_resting; // battery voltage reading at minimum throttle
LowPassFilterFloat _batt_voltage_filt; // filtered battery voltage expressed as a percentage (0 ~ 1.0) of batt_voltage_max
float _batt_current_resting; // battery's current when motors at minimum
float _batt_resistance; // battery's resistance calculated by comparing resting voltage vs in flight voltage
int16_t _batt_timer; // timer used in battery resistance calcs
float _lift_max; // maximum lift ratio from battery voltage
float _throttle_limit; // ratio of throttle limit between hover and maximum
};
#endif // __AP_MOTORS_MULTICOPTER_H__