Mirror
/
ardupilot
mirror of https://github.com/ArduPilot/ardupilot
5
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity
ardupilot/APMrover2/Steering.cpp

307 lines
11 KiB
C++
Raw Blame History

// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
#include "Rover.h"
/*****************************************
Throttle slew limit
*****************************************/
void Rover::throttle_slew_limit(int16_t last_throttle) {
// if slew limit rate is set to zero then do not slew limit
if (g.throttle_slewrate && last_throttle != 0) {
// limit throttle change by the given percentage per second
float temp = g.throttle_slewrate * G_Dt * 0.01f * fabsf(channel_throttle->get_radio_max() - channel_throttle->get_radio_min());
// allow a minimum change of 1 PWM per cycle
if (temp < 1) {
temp = 1;
}
channel_throttle->set_radio_out (constrain_int16(channel_throttle->get_radio_out(), last_throttle - temp, last_throttle + temp));
}
}
/*
check for triggering of start of auto mode
*/
bool Rover::auto_check_trigger(void) {
// only applies to AUTO mode
if (control_mode != AUTO) {
return true;
}
// check for user pressing the auto trigger to off
if (auto_triggered && g.auto_trigger_pin != -1 && check_digital_pin(g.auto_trigger_pin) == 1) {
gcs_send_text(MAV_SEVERITY_WARNING, "AUTO triggered off");
auto_triggered = false;
return false;
}
// if already triggered, then return true, so you don't
// need to hold the switch down
if (auto_triggered) {
return true;
}
if (g.auto_trigger_pin == -1 && is_zero(g.auto_kickstart)) {
// no trigger configured - let's go!
auto_triggered = true;
return true;
}
if (g.auto_trigger_pin != -1 && check_digital_pin(g.auto_trigger_pin) == 0) {
gcs_send_text(MAV_SEVERITY_WARNING, "Triggered AUTO with pin");
auto_triggered = true;
return true;
}
if (!is_zero(g.auto_kickstart)) {
float xaccel = ins.get_accel().x;
if (xaccel >= g.auto_kickstart) {
gcs_send_text_fmt(MAV_SEVERITY_WARNING, "Triggered AUTO xaccel=%.1f", (double)xaccel);
auto_triggered = true;
return true;
}
}
return false;
}
/*
work out if we are going to use pivot steering
*/
bool Rover::use_pivot_steering(void) {
if (control_mode >= AUTO && g.skid_steer_out && g.pivot_turn_angle != 0) {
int16_t bearing_error = wrap_180_cd(nav_controller->target_bearing_cd() - ahrs.yaw_sensor) / 100;
if (abs(bearing_error) > g.pivot_turn_angle) {
return true;
}
}
return false;
}
/*
calculate the throtte for auto-throttle modes
*/
void Rover::calc_throttle(float target_speed) {
// If not autostarting OR we are loitering at a waypoint
// then set the throttle to minimum
if (!auto_check_trigger() || ((loiter_time > 0) && (control_mode == AUTO))) {
channel_throttle->set_servo_out(g.throttle_min.get());
return;
}
float throttle_base = (fabsf(target_speed) / g.speed_cruise) * g.throttle_cruise;
int throttle_target = throttle_base + throttle_nudge;
/*
reduce target speed in proportion to turning rate, up to the
SPEED_TURN_GAIN percentage.
*/
float steer_rate = fabsf(lateral_acceleration / (g.turn_max_g*GRAVITY_MSS));
steer_rate = constrain_float(steer_rate, 0.0f, 1.0f);
// use g.speed_turn_gain for a 90 degree turn, and in proportion
// for other turn angles
int32_t turn_angle = wrap_180_cd(next_navigation_leg_cd - ahrs.yaw_sensor);
float speed_turn_ratio = constrain_float(fabsf(turn_angle / 9000.0f), 0, 1);
float speed_turn_reduction = (100 - g.speed_turn_gain) * speed_turn_ratio * 0.01f;
float reduction = 1.0f - steer_rate*speed_turn_reduction;
if (control_mode >= AUTO && wp_distance <= g.speed_turn_dist) {
// in auto-modes we reduce speed when approaching waypoints
float reduction2 = 1.0f - speed_turn_reduction;
if (reduction2 < reduction) {
reduction = reduction2;
}
}
// reduce the target speed by the reduction factor
target_speed *= reduction;
groundspeed_error = fabsf(target_speed) - ground_speed;
throttle = throttle_target + (g.pidSpeedThrottle.get_pid(groundspeed_error * 100) / 100);
// also reduce the throttle by the reduction factor. This gives a
// much faster response in turns
throttle *= reduction;
if (in_reverse) {
channel_throttle->set_servo_out(constrain_int16(-throttle, -g.throttle_max, -g.throttle_min));
} else {
channel_throttle->set_servo_out(constrain_int16(throttle, g.throttle_min, g.throttle_max));
}
if (!in_reverse && g.braking_percent != 0 && groundspeed_error < -g.braking_speederr) {
// the user has asked to use reverse throttle to brake. Apply
// it in proportion to the ground speed error, but only when
// our ground speed error is more than BRAKING_SPEEDERR.
//
// We use a linear gain, with 0 gain at a ground speed error
// of braking_speederr, and 100% gain when groundspeed_error
// is 2*braking_speederr
float brake_gain = constrain_float(((-groundspeed_error)-g.braking_speederr)/g.braking_speederr, 0, 1);
int16_t braking_throttle = g.throttle_max * (g.braking_percent * 0.01f) * brake_gain;
channel_throttle->set_servo_out(constrain_int16(-braking_throttle, -g.throttle_max, -g.throttle_min));
// temporarily set us in reverse to allow the PWM setting to
// go negative
set_reverse(true);
}
if (use_pivot_steering()) {
channel_throttle->set_servo_out(0);
}
}
/*****************************************
Calculate desired turn angles (in medium freq loop)
*****************************************/
void Rover::calc_lateral_acceleration() {
switch (control_mode) {
case AUTO:
nav_controller->update_waypoint(prev_WP, next_WP);
break;
case RTL:
case GUIDED:
case STEERING:
nav_controller->update_waypoint(current_loc, next_WP);
break;
default:
return;
}
// Calculate the required turn of the wheels
// negative error = left turn
// positive error = right turn
lateral_acceleration = nav_controller->lateral_acceleration();
if (use_pivot_steering()) {
int16_t bearing_error = wrap_180_cd(nav_controller->target_bearing_cd() - ahrs.yaw_sensor) / 100;
if (bearing_error > 0) {
lateral_acceleration = g.turn_max_g*GRAVITY_MSS;
} else {
lateral_acceleration = -g.turn_max_g*GRAVITY_MSS;
}
}
}
/*
calculate steering angle given lateral_acceleration
*/
void Rover::calc_nav_steer() {
// check to see if the rover is loitering
if ((loiter_time > 0) && (control_mode == AUTO)) {
channel_steer->set_servo_out(0);
return;
}
// add in obstacle avoidance
lateral_acceleration += (obstacle.turn_angle/45.0f) * g.turn_max_g;
// constrain to max G force
lateral_acceleration = constrain_float(lateral_acceleration, -g.turn_max_g*GRAVITY_MSS, g.turn_max_g*GRAVITY_MSS);
channel_steer->set_servo_out(steerController.get_steering_out_lat_accel(lateral_acceleration));
}
/*****************************************
Set the flight control servos based on the current calculated values
*****************************************/
void Rover::set_servos(void) {
static int16_t last_throttle;
// support a separate steering channel
RC_Channel_aux::set_servo_out_for(RC_Channel_aux::k_steering, channel_steer->pwm_to_angle_dz(0));
if (control_mode == MANUAL || control_mode == LEARNING) {
// do a direct pass through of radio values
channel_steer->set_radio_out(channel_steer->read());
channel_throttle->set_radio_out(channel_throttle->read());
if (failsafe.bits & FAILSAFE_EVENT_THROTTLE) {
// suppress throttle if in failsafe and manual
channel_throttle->set_radio_out(channel_throttle->get_radio_trim());
}
} else {
channel_steer->calc_pwm();
if (in_reverse) {
channel_throttle->set_servo_out(constrain_int16(channel_throttle->get_servo_out(),
-g.throttle_max,
-g.throttle_min));
} else {
channel_throttle->set_servo_out(constrain_int16(channel_throttle->get_servo_out(),
g.throttle_min.get(),
g.throttle_max.get()));
}
if ((failsafe.bits & FAILSAFE_EVENT_THROTTLE) && control_mode < AUTO) {
// suppress throttle if in failsafe
channel_throttle->set_servo_out(0);
}
if (!hal.util->get_soft_armed()) {
channel_throttle->set_servo_out(0);
}
// convert 0 to 100% into PWM
channel_throttle->calc_pwm();
// limit throttle movement speed
throttle_slew_limit(last_throttle);
}
// record last throttle before we apply skid steering
last_throttle = channel_throttle->get_radio_out();
if (g.skid_steer_out) {
// convert the two radio_out values to skid steering values
/*
mixing rule:
steering = motor1 - motor2
throttle = 0.5*(motor1 + motor2)
motor1 = throttle + 0.5*steering
motor2 = throttle - 0.5*steering
*/
float steering_scaled = channel_steer->norm_output();
float throttle_scaled = channel_throttle->norm_output();
float motor1 = throttle_scaled + 0.5f*steering_scaled;
float motor2 = throttle_scaled - 0.5f*steering_scaled;
channel_steer->set_servo_out(4500*motor1);
channel_throttle->set_servo_out(100*motor2);
channel_steer->calc_pwm();
channel_throttle->calc_pwm();
}
if (!arming.is_armed()) {
//Some ESCs get noisy (beep error msgs) if PWM == 0.
//This little segment aims to avoid this.
switch (arming.arming_required()) {
case AP_Arming::NO:
//keep existing behavior: do nothing to radio_out
//(don't disarm throttle channel even if AP_Arming class is)
break;
case AP_Arming::YES_ZERO_PWM:
channel_throttle->set_radio_out(0);
break;
case AP_Arming::YES_MIN_PWM:
default:
channel_throttle->set_radio_out(channel_throttle->get_radio_trim());
break;
}
}
#if HIL_MODE == HIL_MODE_DISABLED || HIL_SERVOS
// send values to the PWM timers for output
// ----------------------------------------
channel_steer->output();
channel_throttle->output();
RC_Channel_aux::output_ch_all();
#endif
}
Reference in New Issue View Git Blame Copy Permalink