ardupilot/APMrover2/mode_steering.cpp

56 lines
2.0 KiB
C++

#include "mode.h"
#include "Rover.h"
void ModeSteering::update()
{
float desired_steering, desired_throttle;
get_pilot_desired_steering_and_throttle(desired_steering, desired_throttle);
// convert pilot throttle input to desired speed (up to twice the cruise speed)
float target_speed = desired_throttle * 0.01f * calc_speed_max(g.speed_cruise, g.throttle_cruise * 0.01f);
// get speed forward
float speed;
if (!attitude_control.get_forward_speed(speed)) {
// no valid speed so stop
g2.motors.set_throttle(0.0f);
g2.motors.set_steering(0.0f);
return;
}
// determine if pilot is requesting pivot turn
bool is_pivot_turning = g2.motors.have_skid_steering() && is_zero(target_speed) && (!is_zero(desired_steering));
// In steering mode we control lateral acceleration directly.
// For pivot steering vehicles we use the TURN_MAX_G parameter
// For regular steering vehicles we use the maximum lateral acceleration at full steering lock for this speed: V^2/R where R is the radius of turn.
float max_g_force;
if (is_pivot_turning) {
max_g_force = g.turn_max_g * GRAVITY_MSS;
} else {
max_g_force = speed * speed / MAX(g2.turn_radius, 0.1f);
}
// constrain to user set TURN_MAX_G
max_g_force = constrain_float(max_g_force, 0.1f, g.turn_max_g * GRAVITY_MSS);
// convert pilot steering input to desired lateral acceleration
float desired_lat_accel = max_g_force * (desired_steering / 4500.0f);
// reverse target lateral acceleration if backing up
bool reversed = false;
if (is_negative(target_speed)) {
reversed = true;
desired_lat_accel = -desired_lat_accel;
}
// mark us as in_reverse when using a negative throttle
rover.set_reverse(reversed);
// run lateral acceleration to steering controller
calc_steering_from_lateral_acceleration(desired_lat_accel, reversed);
// run speed to throttle controller
calc_throttle(target_speed, false, true);
}