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ardupilot/APMrover2/Steering.cpp

359 lines
13 KiB
C++
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#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;
}
uint16_t pwm;
if (SRV_Channels::get_output_pwm(SRV_Channel::k_throttle, pwm)) {
SRV_Channels::set_output_pwm(SRV_Channel::k_throttle, constrain_int16(pwm, 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)) {
const float xaccel = ins.get_accel().x;
if (xaccel >= g.auto_kickstart) {
gcs_send_text_fmt(MAV_SEVERITY_WARNING, "Triggered AUTO xaccel=%.1f", static_cast<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) {
const 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;
}
/*
test if we are loitering AND should be stopped at a waypoint
*/
bool Rover::in_stationary_loiter()
{
// Confirm we are in AUTO mode and need to loiter for a time period
if ((loiter_start_time > 0) && (control_mode == AUTO)) {
// Check if active loiter is enabled AND we are outside the waypoint loiter radius
// then the vehicle still needs to move so return false
if (active_loiter && (wp_distance > g.waypoint_radius)) {
return false;
}
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() || in_stationary_loiter()) {
SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, g.throttle_min.get());
// Stop rotation in case of loitering and skid steering
if (g.skid_steer_out) {
SRV_Channels::set_output_scaled(SRV_Channel::k_steering, 0);
}
return;
}
const float throttle_base = (fabsf(target_speed) / g.speed_cruise) * g.throttle_cruise;
const 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
const int32_t turn_angle = wrap_180_cd(next_navigation_leg_cd - ahrs.yaw_sensor);
const float speed_turn_ratio = constrain_float(fabsf(turn_angle / 9000.0f), 0, 1);
const 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
const 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) {
SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, constrain_int16(-throttle, -g.throttle_max, -g.throttle_min));
} else {
SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, 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
const float brake_gain = constrain_float(((-groundspeed_error)-g.braking_speederr)/g.braking_speederr, 0, 1);
const int16_t braking_throttle = g.throttle_max * (g.braking_percent * 0.01f) * brake_gain;
SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, 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()) {
SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, 0);
}
}
/*****************************************
Calculate desired turn angles (in medium freq loop)
*****************************************/
void Rover::calc_lateral_acceleration() {
switch (control_mode) {
case AUTO:
// If we have reached the waypoint previously navigate
// back to it from our current position
if (previously_reached_wp && (loiter_duration > 0)) {
nav_controller->update_waypoint(current_loc, next_WP);
} else {
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()) {
const 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 (in_stationary_loiter()) {
SRV_Channels::set_output_scaled(SRV_Channel::k_steering, 0);
return;
}
// add in obstacle avoidance
if (!in_reverse) {
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);
SRV_Channels::set_output_scaled(SRV_Channel::k_steering, 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 uint16_t last_throttle;
bool apply_skid_mix = true; // Normaly true, false when the mixage is done by the controler with skid_steer_in = 1
if (control_mode == MANUAL || control_mode == LEARNING) {
// do a direct pass through of radio values
SRV_Channels::set_output_pwm(SRV_Channel::k_steering, channel_steer->read());
SRV_Channels::set_output_pwm(SRV_Channel::k_throttle, channel_throttle->read());
if (failsafe.bits & FAILSAFE_EVENT_THROTTLE) {
// suppress throttle if in failsafe and manual
SRV_Channels::set_output_pwm(SRV_Channel::k_throttle, channel_throttle->get_radio_trim());
// suppress steer if in failsafe and manual and skid steer mode
if (g.skid_steer_out) {
SRV_Channels::set_output_pwm(SRV_Channel::k_steering, channel_steer->get_radio_trim());
}
}
if (g.skid_steer_in) {
apply_skid_mix = false;
}
} else {
if (in_reverse) {
SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, constrain_int16(SRV_Channels::get_output_scaled(SRV_Channel::k_throttle),
-g.throttle_max,
-g.throttle_min));
} else {
SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, constrain_int16(SRV_Channels::get_output_scaled(SRV_Channel::k_throttle),
g.throttle_min.get(),
g.throttle_max.get()));
}
if ((failsafe.bits & FAILSAFE_EVENT_THROTTLE) && control_mode < AUTO) {
// suppress throttle if in failsafe
SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, 0);
// suppress steer if in failsafe and skid steer mode
if (g.skid_steer_out) {
SRV_Channels::set_output_scaled(SRV_Channel::k_steering, 0);
}
}
if (!hal.util->get_soft_armed()) {
SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, 0);
// suppress steer if in failsafe and skid steer mode
if (g.skid_steer_out) {
SRV_Channels::set_output_scaled(SRV_Channel::k_steering, 0);
}
}
// limit throttle movement speed
throttle_slew_limit(last_throttle);
}
// record last throttle before we apply skid steering
SRV_Channels::get_output_pwm(SRV_Channel::k_throttle, last_throttle);
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
*/
const float steering_scaled = SRV_Channels::get_output_norm(SRV_Channel::k_steering);
const float throttle_scaled = SRV_Channels::get_output_norm(SRV_Channel::k_throttle);
float motor1 = throttle_scaled + 0.5f * steering_scaled;
float motor2 = throttle_scaled - 0.5f * steering_scaled;
if (!apply_skid_mix) { // Mixage is already done by a controller so just pass the value to motor
motor1 = steering_scaled;
motor2 = throttle_scaled;
} else if (fabsf(throttle_scaled) <= 0.01f) { // Use full range for on spot turn
motor1 = steering_scaled;
motor2 = -steering_scaled;
}
SRV_Channels::set_output_scaled(SRV_Channel::k_steering, 4500 * motor1);
SRV_Channels::set_output_scaled(SRV_Channel::k_throttle, 100 * motor2);
}
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:
SRV_Channels::set_output_pwm(SRV_Channel::k_throttle, 0);
if (g.skid_steer_out) {
SRV_Channels::set_output_pwm(SRV_Channel::k_steering, 0);
}
break;
case AP_Arming::YES_MIN_PWM:
default:
SRV_Channels::set_output_pwm(SRV_Channel::k_throttle, channel_throttle->get_radio_trim());
if (g.skid_steer_out) {
SRV_Channels::set_output_pwm(SRV_Channel::k_steering, channel_steer->get_radio_trim());
}
break;
}
}
SRV_Channels::calc_pwm();
#if HIL_MODE == HIL_MODE_DISABLED || HIL_SERVOS
// send values to the PWM timers for output
// ----------------------------------------
SRV_Channels::output_ch_all();
#endif
}
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