ardupilot/ArduCopter/Attitude.cpp

313 lines
11 KiB
C++

#include "Copter.h"
// get_smoothing_gain - returns smoothing gain to be passed into attitude_control->input_euler_angle_roll_pitch_euler_rate_yaw
// result is a number from 2 to 12 with 2 being very sluggish and 12 being very crisp
float Copter::get_smoothing_gain()
{
return (2.0f + (float)g.rc_feel_rp/10.0f);
}
// get_pilot_desired_angle - transform pilot's roll or pitch input into a desired lean angle
// returns desired angle in centi-degrees
void Copter::get_pilot_desired_lean_angles(float roll_in, float pitch_in, float &roll_out, float &pitch_out, float angle_max)
{
// sanity check angle max parameter
aparm.angle_max = constrain_int16(aparm.angle_max,1000,8000);
// limit max lean angle
angle_max = constrain_float(angle_max, 1000, aparm.angle_max);
// scale roll_in, pitch_in to ANGLE_MAX parameter range
float scaler = aparm.angle_max/(float)ROLL_PITCH_YAW_INPUT_MAX;
roll_in *= scaler;
pitch_in *= scaler;
// do circular limit
float total_in = norm(pitch_in, roll_in);
if (total_in > angle_max) {
float ratio = angle_max / total_in;
roll_in *= ratio;
pitch_in *= ratio;
}
// do lateral tilt to euler roll conversion
roll_in = (18000/M_PI) * atanf(cosf(pitch_in*(M_PI/18000))*tanf(roll_in*(M_PI/18000)));
// return
roll_out = roll_in;
pitch_out = pitch_in;
}
// get_pilot_desired_heading - transform pilot's yaw input into a
// desired yaw rate
// returns desired yaw rate in centi-degrees per second
float Copter::get_pilot_desired_yaw_rate(int16_t stick_angle)
{
float yaw_request;
// calculate yaw rate request
if (g2.acro_y_expo <= 0) {
yaw_request = stick_angle * g.acro_yaw_p;
} else {
// expo variables
float y_in, y_in3, y_out;
// range check expo
if (g2.acro_y_expo > 1.0f || g2.acro_y_expo < 0.5f) {
g2.acro_y_expo = 1.0f;
}
// yaw expo
y_in = float(stick_angle)/ROLL_PITCH_YAW_INPUT_MAX;
y_in3 = y_in*y_in*y_in;
y_out = (g2.acro_y_expo * y_in3) + ((1.0f - g2.acro_y_expo) * y_in);
yaw_request = ROLL_PITCH_YAW_INPUT_MAX * y_out * g.acro_yaw_p;
}
// convert pilot input to the desired yaw rate
return yaw_request;
}
/*************************************************************
* yaw controllers
*************************************************************/
// get_roi_yaw - returns heading towards location held in roi_WP
// should be called at 100hz
float Copter::get_roi_yaw()
{
static uint8_t roi_yaw_counter = 0; // used to reduce update rate to 100hz
roi_yaw_counter++;
if (roi_yaw_counter >= 4) {
roi_yaw_counter = 0;
yaw_look_at_WP_bearing = pv_get_bearing_cd(inertial_nav.get_position(), roi_WP);
}
return yaw_look_at_WP_bearing;
}
float Copter::get_look_ahead_yaw()
{
const Vector3f& vel = inertial_nav.get_velocity();
float speed = norm(vel.x,vel.y);
// Commanded Yaw to automatically look ahead.
if (position_ok() && (speed > YAW_LOOK_AHEAD_MIN_SPEED)) {
yaw_look_ahead_bearing = degrees(atan2f(vel.y,vel.x))*100.0f;
}
return yaw_look_ahead_bearing;
}
/*************************************************************
* throttle control
****************************************************************/
// update estimated throttle required to hover (if necessary)
// called at 100hz
void Copter::update_throttle_hover()
{
#if FRAME_CONFIG != HELI_FRAME
// if not armed or landed exit
if (!motors->armed() || ap.land_complete) {
return;
}
// do not update in manual throttle modes or Drift
if (mode_has_manual_throttle(control_mode) || (control_mode == DRIFT)) {
return;
}
// do not update while climbing or descending
if (!is_zero(pos_control->get_desired_velocity().z)) {
return;
}
// get throttle output
float throttle = motors->get_throttle();
// calc average throttle if we are in a level hover
if (throttle > 0.0f && abs(climb_rate) < 60 && labs(ahrs.roll_sensor) < 500 && labs(ahrs.pitch_sensor) < 500) {
// Can we set the time constant automatically
motors->update_throttle_hover(0.01f);
}
#endif
}
// set_throttle_takeoff - allows parents to tell throttle controller we are taking off so I terms can be cleared
void Copter::set_throttle_takeoff()
{
// tell position controller to reset alt target and reset I terms
pos_control->init_takeoff();
}
// transform pilot's manual throttle input to make hover throttle mid stick
// used only for manual throttle modes
// thr_mid should be in the range 0 to 1
// returns throttle output 0 to 1
float Copter::get_pilot_desired_throttle(int16_t throttle_control, float thr_mid)
{
if (thr_mid <= 0.0f) {
thr_mid = motors->get_throttle_hover();
}
int16_t mid_stick = channel_throttle->get_control_mid();
// protect against unlikely divide by zero
if (mid_stick <= 0) {
mid_stick = 500;
}
// ensure reasonable throttle values
throttle_control = constrain_int16(throttle_control,0,1000);
// calculate normalised throttle input
float throttle_in;
if (throttle_control < mid_stick) {
// below the deadband
throttle_in = ((float)throttle_control)*0.5f/(float)mid_stick;
}else if(throttle_control > mid_stick) {
// above the deadband
throttle_in = 0.5f + ((float)(throttle_control-mid_stick)) * 0.5f / (float)(1000-mid_stick);
}else{
// must be in the deadband
throttle_in = 0.5f;
}
float expo = constrain_float(-(thr_mid-0.5)/0.375, -0.5f, 1.0f);
// calculate the output throttle using the given expo function
float throttle_out = throttle_in*(1.0f-expo) + expo*throttle_in*throttle_in*throttle_in;
return throttle_out;
}
// get_pilot_desired_climb_rate - transform pilot's throttle input to climb rate in cm/s
// without any deadzone at the bottom
float Copter::get_pilot_desired_climb_rate(float throttle_control)
{
// throttle failsafe check
if( failsafe.radio ) {
return 0.0f;
}
float desired_rate = 0.0f;
float mid_stick = channel_throttle->get_control_mid();
float deadband_top = mid_stick + g.throttle_deadzone;
float deadband_bottom = mid_stick - g.throttle_deadzone;
// ensure a reasonable throttle value
throttle_control = constrain_float(throttle_control,0.0f,1000.0f);
// ensure a reasonable deadzone
g.throttle_deadzone = constrain_int16(g.throttle_deadzone, 0, 400);
// check throttle is above, below or in the deadband
if (throttle_control < deadband_bottom) {
// below the deadband
desired_rate = g.pilot_velocity_z_max * (throttle_control-deadband_bottom) / deadband_bottom;
}else if (throttle_control > deadband_top) {
// above the deadband
desired_rate = g.pilot_velocity_z_max * (throttle_control-deadband_top) / (1000.0f-deadband_top);
}else{
// must be in the deadband
desired_rate = 0.0f;
}
// desired climb rate for logging
desired_climb_rate = desired_rate;
return desired_rate;
}
// get_non_takeoff_throttle - a throttle somewhere between min and mid throttle which should not lead to a takeoff
float Copter::get_non_takeoff_throttle()
{
return MAX(0,motors->get_throttle_hover()/2.0f);
}
// get_surface_tracking_climb_rate - hold copter at the desired distance above the ground
// returns climb rate (in cm/s) which should be passed to the position controller
float Copter::get_surface_tracking_climb_rate(int16_t target_rate, float current_alt_target, float dt)
{
#if RANGEFINDER_ENABLED == ENABLED
static uint32_t last_call_ms = 0;
float distance_error;
float velocity_correction;
float current_alt = inertial_nav.get_altitude();
uint32_t now = millis();
// reset target altitude if this controller has just been engaged
if (now - last_call_ms > RANGEFINDER_TIMEOUT_MS) {
target_rangefinder_alt = rangefinder_state.alt_cm + current_alt_target - current_alt;
}
last_call_ms = now;
// adjust rangefinder target alt if motors have not hit their limits
if ((target_rate<0 && !motors->limit.throttle_lower) || (target_rate>0 && !motors->limit.throttle_upper)) {
target_rangefinder_alt += target_rate * dt;
}
/*
handle rangefinder glitches. When we get a rangefinder reading
more than RANGEFINDER_GLITCH_ALT_CM different from the current
rangefinder reading then we consider it a glitch and reject
until we get RANGEFINDER_GLITCH_NUM_SAMPLES samples in a
row. When that happens we reset the target altitude to the new
reading
*/
int32_t glitch_cm = rangefinder_state.alt_cm - target_rangefinder_alt;
if (glitch_cm >= RANGEFINDER_GLITCH_ALT_CM) {
rangefinder_state.glitch_count = MAX(rangefinder_state.glitch_count+1,1);
} else if (glitch_cm <= -RANGEFINDER_GLITCH_ALT_CM) {
rangefinder_state.glitch_count = MIN(rangefinder_state.glitch_count-1,-1);
} else {
rangefinder_state.glitch_count = 0;
}
if (abs(rangefinder_state.glitch_count) >= RANGEFINDER_GLITCH_NUM_SAMPLES) {
// shift to the new rangefinder reading
target_rangefinder_alt = rangefinder_state.alt_cm;
rangefinder_state.glitch_count = 0;
}
if (rangefinder_state.glitch_count != 0) {
// we are currently glitching, just use the target rate
return target_rate;
}
// calc desired velocity correction from target rangefinder alt vs actual rangefinder alt (remove the error already passed to Altitude controller to avoid oscillations)
distance_error = (target_rangefinder_alt - rangefinder_state.alt_cm) - (current_alt_target - current_alt);
velocity_correction = distance_error * g.rangefinder_gain;
velocity_correction = constrain_float(velocity_correction, -THR_SURFACE_TRACKING_VELZ_MAX, THR_SURFACE_TRACKING_VELZ_MAX);
// return combined pilot climb rate + rate to correct rangefinder alt error
return (target_rate + velocity_correction);
#else
return (float)target_rate;
#endif
}
// get target climb rate reduced to avoid obstacles and altitude fence
float Copter::get_avoidance_adjusted_climbrate(float target_rate)
{
#if AC_AVOID_ENABLED == ENABLED
avoid.adjust_velocity_z(pos_control->get_pos_z_kP(), pos_control->get_accel_z(), target_rate);
return target_rate;
#else
return target_rate;
#endif
}
// set_accel_throttle_I_from_pilot_throttle - smoothes transition from pilot controlled throttle to autopilot throttle
void Copter::set_accel_throttle_I_from_pilot_throttle()
{
// get last throttle input sent to attitude controller
float pilot_throttle = constrain_float(attitude_control->get_throttle_in(), 0.0f, 1.0f);
// shift difference between pilot's throttle and hover throttle into accelerometer I
g.pid_accel_z.set_integrator((pilot_throttle-motors->get_throttle_hover()) * 1000.0f);
}
// rotate vector from vehicle's perspective to North-East frame
void Copter::rotate_body_frame_to_NE(float &x, float &y)
{
float ne_x = x*ahrs.cos_yaw() - y*ahrs.sin_yaw();
float ne_y = x*ahrs.sin_yaw() + y*ahrs.cos_yaw();
x = ne_x;
y = ne_y;
}