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Copter: Hybrid fixes to wind_comp, brake pitch timer, thr peaks 

There was an error in the velocity axis used to update
brake_timeout_pitch (vel_right instead of vel_fw)

The wind_comp was not enough filtered for the Pixhawk (400Hz), so I
added a specific time constant (TC_WIND_COMP) to have the expected
filter with 400Hz controllers.

About throttle peaks, after some tests and from logs, they happen when
hybrid switches to loiter.
There is always a difference between Alt and DesiredAlt (DAlt), but,
when loiter engages, it initializes DAlt = Alt and the copter tries
immediatelly to reach that new setpoint. So the solution would be to
init_loiter_target() just as it was in pre-onion code : only x/y and not
z. and to be able to pass parameters like that
wp_nav.init_loiter_target(inertial_nav.get_position(), Vector3f(0,0,0));

Well, from this new code structure, it seems not possible with current
functions so I've used set_loiter_target that init position passed as
parameter and velocity to 0 (as expected).
BTW, I think there was something wrong with set_loiter_target function,
the "Vector3f& position" parameter was not used at all...
I moved the reset flag from init_loiter_target to set_loiter_target.
This commit is contained in:
Ju1ien 2014-04-23 13:40:03 +09:00 committed by Randy Mackay
parent 14cbb09804
commit ff532a06ec
1 changed files with 27 additions and 21 deletions
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48
ArduCopter/control_hybrid.pde
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@ -11,20 +11,20 @@
// definitions for 100hz loop update rate
# define HYBRID_BRAKE_TIME_ESTIMATE_MAX 600 // max number of cycles the brake will be applied before we switch to loiter
# define HYBRID_BRAKE_TO_LOITER_TIMER 150 // Number of cycles to transition from brake mode to loiter mode.
# define HYBRID_WIND_COMP_START_TIMER 150 // Number of cycles to start wind compensation update after loiter is engaged
# define HYBRID_CONTROLLER_TO_PILOT_MIX_TIMER 50 // Set it from 100 to 200, the number of centiseconds loiter and manual commands are mixed to make a smooth transition.
# define HYBRID_SMOOTH_RATE_FACTOR 0.05f // filter applied to pilot's roll/pitch input as it returns to center. A lower number will cause the roll/pitch to return to zero more slowly if the brake_rate is also low.
# define HYBRID_WIND_COMP_TIMER_10HZ 10 // counter value used to reduce wind compensation to 10hz
# define LOOP_RATE_FACTOR 1 // used to adapt hybrid params to loop_rate
# define TC_WIND_COMP 0.01f // Time constant for hybrid_update_wind_comp_estimate()
#else
// definitions for 400hz loop update rate
# define HYBRID_BRAKE_TIME_ESTIMATE_MAX (600*4) // max number of cycles the brake will be applied before we switch to loiter
# define HYBRID_BRAKE_TO_LOITER_TIMER (150*4) // Number of cycles to transition from brake mode to loiter mode. Must be lower than HYBRID_LOITER_STAB_TIMER
# define HYBRID_WIND_COMP_START_TIMER (150*4) // Number of cycles to start wind compensation update after loiter is engaged
# define HYBRID_CONTROLLER_TO_PILOT_MIX_TIMER (50*4) // Set it from 100 to 200, the number of centiseconds loiter and manual commands are mixed to make a smooth transition.
# define HYBRID_SMOOTH_RATE_FACTOR 0.0125f // filter applied to pilot's roll/pitch input as it returns to center. A lower number will cause the roll/pitch to return to zero more slowly if the brake_rate is also low.
# define HYBRID_WIND_COMP_TIMER_10HZ 40 // counter value used to reduce wind compensation to 10hz
# define LOOP_RATE_FACTOR 4 // used to adapt hybrid params to loop_rate
# define TC_WIND_COMP 0.0025f // Time constant for hybrid_update_wind_comp_estimate()
#endif
// definitions that are independent of main loop rate
@ -90,6 +90,8 @@ static struct {
int16_t pitch; // final pitch angle sent to attitude controller
} hybrid;
static bool reset_I = true;
// hybrid_init - initialise hybrid controller
static bool hybrid_init(bool ignore_checks)
{
@ -98,21 +100,15 @@ static bool hybrid_init(bool ignore_checks)
return false;
}
// set target to current position
wp_nav.init_loiter_target();
// clear pilot's feed forward for roll and pitch
wp_nav.set_pilot_desired_acceleration(0, 0);
// initialise altitude target to stopping point
pos_control.set_target_to_stopping_point_z();
// initialize vertical speeds and leash lengths
pos_control.set_speed_z(-g.pilot_velocity_z_max, g.pilot_velocity_z_max);
// initialise lean angles to current attitude
hybrid.pilot_roll = 0;
hybrid.pilot_pitch = 0;
// JD - These variables will be written in hybrid_run before being used.
// hybrid.roll = constrain_int16(ahrs.roll_sensor, -g.hybrid_brake_angle_max, g.hybrid_brake_angle_max);
// hybrid.pitch = constrain_int16(ahrs.pitch_sensor, -g.hybrid_brake_angle_max, g.hybrid_brake_angle_max);
// compute brake_gain
hybrid.brake_gain = (15.0f * (float)g.hybrid_brake_rate + 95.0f) / 100.0f;
@ -121,6 +117,10 @@ static bool hybrid_init(bool ignore_checks)
// if landed begin in loiter mode
hybrid.roll_mode = HYBRID_LOITER;
hybrid.pitch_mode = HYBRID_LOITER;
// set target to current position
// only init here as we can switch to hybrid in flight with a velocity <> 0 that will be used as _last_vel in PosControl and never updated again as we inhibit Reset_I
wp_nav.init_loiter_target();
}else{
// if not landed start in pilot override to avoid hard twitch
hybrid.roll_mode = HYBRID_PILOT_OVERRIDE;
@ -143,7 +143,7 @@ static void hybrid_run()
{
int16_t target_roll, target_pitch; // pilot's roll and pitch angle inputs
float target_yaw_rate = 0; // pilot desired yaw rate in centi-degrees/sec
float target_climb_rate = 0; // pilot desired climb rate in centimeters/sec
int16_t target_climb_rate = 0; // pilot desired climb rate in centimeters/sec
float brake_to_loiter_mix; // mix of brake and loiter controls. 0 = fully brake controls, 1 = fully loiter controls
float controller_to_pilot_roll_mix; // mix of controller and pilot controls. 0 = fully last controller controls, 1 = fully pilot controls
float controller_to_pilot_pitch_mix; // mix of controller and pilot controls. 0 = fully last controller controls, 1 = fully pilot controls
@ -151,7 +151,7 @@ static void hybrid_run()
const Vector3f& vel = inertial_nav.get_velocity();
// if not auto armed set throttle to zero and exit immediately
if(!ap.auto_armed || !inertial_nav.position_ok()) { // JD - I hope this condition is safe!
if(!ap.auto_armed || !inertial_nav.position_ok()) {
wp_nav.init_loiter_target();
attitude_control.init_targets();
attitude_control.set_throttle_out(0, false);
@ -338,8 +338,7 @@ static void hybrid_run()
}
// if velocity is very low reduce braking time to 0.5seconds
// Note: this speed is extremely low (only 10cm/s) meaning this case is likely never executed
if ((fabs(vel_right) <= HYBRID_SPEED_0) && (hybrid.brake_timeout_pitch > 50*LOOP_RATE_FACTOR)) {
if ((fabs(vel_fw) <= HYBRID_SPEED_0) && (hybrid.brake_timeout_pitch > 50*LOOP_RATE_FACTOR)) {
hybrid.brake_timeout_pitch = 50*LOOP_RATE_FACTOR;
}
@ -399,7 +398,11 @@ static void hybrid_run()
hybrid.pitch_mode = HYBRID_BRAKE_TO_LOITER;
hybrid.brake_to_loiter_timer = HYBRID_BRAKE_TO_LOITER_TIMER;
// init loiter controller
wp_nav.init_loiter_target(false); // (false) to avoid I_term reset. In original code, velocity(0,0,0) was used instead of current velocity: wp_nav.init_loiter_target(inertial_nav.get_position(), Vector3f(0,0,0));
Vector3f curr_pos = inertial_nav.get_position();
curr_pos.z = pos_control.get_alt_target(); // We don't set alt_target to current altitude but to the current alt_target... the easiest would be to set only x/y as it was on pre-onion code
wp_nav.set_loiter_target(curr_pos, reset_I); // (false) to avoid I_term reset. In original code, velocity(0,0,0) was used instead of current velocity: wp_nav.init_loiter_target(inertial_nav.get_position(), Vector3f(0,0,0));
// at this stage, we are going to run update_loiter that will reset I_term once. From now, we ensure next time that we will enter loiter and update it, I_term won't be reset anymore
reset_I = false;
// set delay to start of wind compensation estimate updates
hybrid.wind_comp_start_timer = HYBRID_WIND_COMP_START_TIMER;
}
@ -443,7 +446,8 @@ static void hybrid_run()
// init transition to pilot override
hybrid_roll_controller_to_pilot_override();
// switch pitch-mode to brake (but ready to go back to loiter anytime)
hybrid.pitch_mode = HYBRID_BRAKE_READY_TO_LOITER; // JD : no need to reset hybrid.brake_pitch here as wind comp has not been updated since last brake_pitch computation
// no need to reset hybrid.brake_pitch here as wind comp has not been updated since last brake_pitch computation
hybrid.pitch_mode = HYBRID_BRAKE_READY_TO_LOITER;
}
// if pitch input switch to pilot override for pitch
if (target_pitch != 0) {
@ -451,7 +455,8 @@ static void hybrid_run()
hybrid_pitch_controller_to_pilot_override();
if (target_roll == 0) {
// switch roll-mode to brake (but ready to go back to loiter anytime)
hybrid.roll_mode = HYBRID_BRAKE_READY_TO_LOITER; // JD : no need to reset hybrid.brake_roll here as wind comp has not been updated since last brake_roll computation
// no need to reset hybrid.brake_roll here as wind comp has not been updated since last brake_roll computation
hybrid.roll_mode = HYBRID_BRAKE_READY_TO_LOITER;
}
}
}
@ -476,7 +481,8 @@ static void hybrid_run()
hybrid_roll_controller_to_pilot_override();
// switch pitch-mode to brake (but ready to go back to loiter anytime)
hybrid.pitch_mode = HYBRID_BRAKE_READY_TO_LOITER;
hybrid.brake_pitch = 0; // JD : reset brake_pitch because wind_comp is now different and should give the compensation of the whole previous loiter angle
// reset brake_pitch because wind_comp is now different and should give the compensation of the whole previous loiter angle
hybrid.brake_pitch = 0;
}
// if pitch input switch to pilot override for pitch
if (target_pitch != 0) {
@ -605,14 +611,14 @@ static void hybrid_update_wind_comp_estimate()
hybrid.wind_comp_ef.x = accel_target.x;
} else {
// low pass filter the position controller's lean angle output
hybrid.wind_comp_ef.x = 0.99f*hybrid.wind_comp_ef.x + 0.01f*accel_target.x;
hybrid.wind_comp_ef.x = (1.0f-TC_WIND_COMP)*hybrid.wind_comp_ef.x + TC_WIND_COMP*accel_target.x;
}
if (hybrid.wind_comp_ef.y == 0) {
// if wind compensation has not been initialised set it immediately to the pos controller's desired accel in north direction
hybrid.wind_comp_ef.y = accel_target.y;
} else {
// low pass filter the position controller's lean angle output
hybrid.wind_comp_ef.y = 0.99f*hybrid.wind_comp_ef.y + 0.01f*accel_target.y;
hybrid.wind_comp_ef.y = (1.0f-TC_WIND_COMP)*hybrid.wind_comp_ef.y + TC_WIND_COMP*accel_target.y;
}
}