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APM: added speed scaling to wheeled steering

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this allows for a larger amount of steering control at low speeds
without causing osciallation after takeoff
This commit is contained in:
Andrew Tridgell 2012-09-11 13:01:36 +10:00
parent 65dc4ccc6d
commit 72e9c31c17
1 changed files with 20 additions and 8 deletions
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28
ArduPlane/Attitude.pde
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@ -4,14 +4,15 @@
// Function that controls aileron/rudder, elevator, rudder (if 4 channel control) and throttle to produce desired attitude and airspeed. // Function that controls aileron/rudder, elevator, rudder (if 4 channel control) and throttle to produce desired attitude and airspeed.
//**************************************************************** //****************************************************************
static void stabilize()
{
float ch1_inf = 1.0;
float ch2_inf = 1.0;
float ch4_inf = 1.0;
float speed_scaler;
float aspeed;
/*
get a speed scaling number for control surfaces. This is applied to
PIDs to change the scaling of the PID with speed. At high speed we
move the surfaces less, and at low speeds we move them more.
*/
static float get_speed_scaler(void)
{
float aspeed, speed_scaler;
if (ahrs.airspeed_estimate(&aspeed)) { if (ahrs.airspeed_estimate(&aspeed)) {
if (aspeed > 0) { if (aspeed > 0) {
speed_scaler = g.scaling_speed / aspeed; speed_scaler = g.scaling_speed / aspeed;
@ -29,6 +30,16 @@ static void stabilize()
// This case is constrained tighter as we don't have real speed info // This case is constrained tighter as we don't have real speed info
speed_scaler = constrain(speed_scaler, 0.6, 1.67); speed_scaler = constrain(speed_scaler, 0.6, 1.67);
} }
return speed_scaler;
}
static void stabilize()
{
float ch1_inf = 1.0;
float ch2_inf = 1.0;
float ch4_inf = 1.0;
float speed_scaler = get_speed_scaler();
if(crash_timer > 0) { if(crash_timer > 0) {
nav_roll_cd = 0; nav_roll_cd = 0;
@ -176,7 +187,8 @@ static void calc_nav_yaw(float speed_scaler, float ch4_inf)
{ {
if (hold_course != -1) { if (hold_course != -1) {
// steering on or close to ground // steering on or close to ground
g.channel_rudder.servo_out = g.pidWheelSteer.get_pid(bearing_error_cd) + g.kff_rudder_mix * g.channel_roll.servo_out; g.channel_rudder.servo_out = g.pidWheelSteer.get_pid(bearing_error_cd, speed_scaler) +
g.kff_rudder_mix * g.channel_roll.servo_out;
return; return;
} }