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SITL: use FlightAxis body accel 

less noisy than rotating early accel
This commit is contained in:
Andrew Tridgell 2016-06-04 14:20:55 +10:00
parent f6e42cb3e2
commit f6a7c1839a
1 changed files with 14 additions and 21 deletions
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31
libraries/SITL/SIM_FlightAxis.cpp
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@ -28,6 +28,7 @@
#include <sys/types.h>
#include <AP_HAL/AP_HAL.h>
#include <DataFlash/DataFlash.h>
extern const AP_HAL::HAL& hal;
@ -253,8 +254,6 @@ void FlightAxis::exchange_data(const struct sitl_input &input)
*/
void FlightAxis::update(const struct sitl_input &input)
{
Vector3f last_velocity_ef = velocity_ef;
exchange_data(input);
double dt_seconds = state.m_currentPhysicsTime_SEC - last_time_s;
@ -267,6 +266,7 @@ void FlightAxis::update(const struct sitl_input &input)
}
if (dt_seconds < 0.0001f) {
// we probably got a repeated frame
time_now_us += 1;
return;
}
if (initial_time_s <= 0) {
@ -290,7 +290,16 @@ void FlightAxis::update(const struct sitl_input &input)
state.m_velocityWorldW_MPS);
position = Vector3f(state.m_aircraftPositionY_MTR,
state.m_aircraftPositionX_MTR,
-state.m_altitudeAGL_MTR);
-state.m_altitudeASL_MTR - home.alt*0.01);
accel_body(state.m_accelerationBodyAX_MPS2,
state.m_accelerationBodyAY_MPS2,
state.m_accelerationBodyAZ_MPS2);
// limit to 16G to match pixhawk
float a_limit = GRAVITY_MSS*16;
accel_body.x = constrain_float(accel_body.x, -a_limit, a_limit);
accel_body.y = constrain_float(accel_body.y, -a_limit, a_limit);
accel_body.z = constrain_float(accel_body.z, -a_limit, a_limit);
// offset based on first position to account for offset in RF world
if (position_offset.is_zero() || state.m_resetButtonHasBeenPressed) {
@ -298,22 +307,6 @@ void FlightAxis::update(const struct sitl_input &input)
}
position -= position_offset;
Vector3f accel_ef(state.m_accelerationWorldAX_MPS2,
state.m_accelerationWorldAY_MPS2,
state.m_accelerationWorldAZ_MPS2);
// the accel values given in the state are very strange when on
// the ground. Calculate it from delta-velocity instead, although
// this does introduce noise
if (state.m_isTouchingGround) {
accel_ef = (velocity_ef - last_velocity_ef) / dt_seconds;
}
accel_ef.z -= GRAVITY_MSS;
accel_body = dcm.transposed() * accel_ef;
// limit accel range to what a pixhawk could see
accel_body.x = constrain_float(accel_body.x, -16, 16);
accel_body.y = constrain_float(accel_body.y, -16, 16);
accel_body.z = constrain_float(accel_body.z, -16, 16);
airspeed = state.m_airspeed_MPS;
airspeed_pitot = state.m_airspeed_MPS;