zr-v4

History

Paul Riseborough 10ecffce01 APM_Control: ROLL and PITCH controllers These changes reduce height variation in turns and improve robustness. the specific changes are: 1) Linked roll and pitch integrator protection to the final output value so that if final output is on upper limit, the integrator is prevented from increasing and vice-versa. This improves wind-up protection. 2) Modified rate feedback in roll and pitch controllers to use body rates rather than Euler or earth rates. 3) Changed the roll to pitch compensation to use measured roll angle and estimated airspeed to calculate the component of turn rate (assuming a level coordinated turn) around the pitch axis. This a mathematically correct calculation and will work over a range of bank angles and aircraft with minimal (if any) tuning required. 4) The integrator in the roll and pitch loop is clamped when the estimated speed is below the minimum FBW speed 5) The noise filter in the pitch and roll loop has been changed to use a FOH discretisation. This gives improved noise rejection and less phase loss when compared to the previous filter that used a ZOH or equivalent discretisation. This has been flown on the rascal in the SITL and on a X-8 with limited flight testing. Initial results have been encouraging with reduced height variation in turns. Compare to standard PIDS, the revised pitch and roll controllers allow the use of rate feedback (effectively the same as the old D term) without beating the servos to death. The bank angle compensation in the pitch loop works effectively over a much larger range of bank angles and requires minimal tuning compared to the old calculation. YAW CONTROLLER Currently testing the a 3-loop acceleration autopilot topology for the yaw loop with feed forward yaw rate for turn compensation. This 3-loop topology is commonly used in tactical skid to to turn missiles and is easy to tune. The following block diagram shows the general signal flow Note that the acceleration measurement has to pass through an integrator before it gets to the actuator. This is a important feature as it eliminates problems of high frequency noise and potential coupling with structural modes associated with direct feedback of measured acceleration to actuator. The high pass filter has been inserted to compensate for airspeed and bank angle measurement errors which will cause steady state errors in the calculation of the turn yaw rate. The yaw controller flies SITL well, but hasn't been flight tested yet. It can be configured either as a simple yaw damper, or the acceleration and integral term can be turned on to allow feedback control of lateral acceleration/sideslip. TO DO: Need to reduce number of tuning parameters and provide consistent naming Need to provide guidance on tuning these loops with definitions for all the gain terms. Need to check signs and units into and out of lateral loops. DESIGN DECISIONS PENDING: 1) Can we remove the noise filters? Provided the mpu6k noise filter is running they are of limited benefit given the 25Hz Nyquist frequency 2) If we do remove them and rely on the mpu6k noise filter, what is the apprporiate default cutoff frequency for plane use. 20Hz is probably OK for most setups, but some noisy/high vibration setups would require as low as 10Hz 3) The inverted flight logic looks like a crash waiting to happen. It's problematic to test and even if implemented correctly would still crash a plane with poor inverted flight capability. We should either implement it properly and fully tested or delete it.		12 years ago
..
AC_Fence	AC_Fence: reduce to 150m radius and 100m high	12 years ago
AC_PID	Add AVR compatibility header for missing math.h definitions.	12 years ago
AC_WPNav	Copter: remove jerk when entering RTL or AUTO	12 years ago
APM_Control	APM_Control: ROLL and PITCH controllers	12 years ago
APM_OBC	build: change from Arduino.mk to apm.mk	12 years ago
APM_PI	Add AVR compatibility header for missing math.h definitions.	12 years ago
AP_ADC	AP_ADC: removed unused setHIL method	12 years ago
AP_ADC_AnalogSource	AP_ADC: added dummy stop_pin and settle_time calls	12 years ago
AP_AHRS	AP_AHRS: optimise yaw drift correction	12 years ago
AP_Airspeed	AP_Airspeed: use new voltage_average() API in Airspeed driver	12 years ago
AP_Baro	AP_Baro: fixed a build warning	12 years ago
AP_Buffer	AP_Buffer: remove bool return from add() method	12 years ago
AP_Camera	AP_Camera: enable relay off in all builds	12 years ago
AP_Common	AP_Common: added BIT_IS_SET() macro	12 years ago
AP_Compass	AP_Compass_HIL: fixed indentation	12 years ago
AP_Curve	AP_Curve: put template in cpp file	12 years ago
AP_Declination	AP_Declination: fixed example build	12 years ago
AP_GPS	AP_GPS: added last_message_time_ms() API	12 years ago
AP_HAL	AP_HAL: added set_stop_pin() and set_settle_time() interfaces to analogin	12 years ago
AP_HAL_AVR	HAL_AVR: initialise settle time	12 years ago
AP_HAL_AVR_SITL	SITL: fixed compass vector to be based on yaw not GPS heading	12 years ago
AP_HAL_Empty	HAL_Empty: add new API functions	12 years ago
AP_HAL_PX4	HAL_PX4: fixed build with new AnalogIn API	12 years ago
AP_HAL_SMACCM	HAL_SMACCM: fixed build for new AnalogIn API	12 years ago
AP_InertialNav	InertialNav: use AP_Math's longitude_scale	12 years ago
AP_InertialSensor	SITL: fixed drift rate limit in simulator	12 years ago
AP_L1_Control	AP_L1_Control: Cleaned up calculation of damping to reduce computations	12 years ago
AP_LeadFilter	build: change from Arduino.mk to apm.mk	12 years ago
AP_Limits	AP_Limits: fixed return of AP_Int8 parameters from object	12 years ago
AP_Math	AP_Math: use DEG_TO_RAD in longitude_scale	12 years ago
AP_Menu	AP_Menu: fixed crash bug in strtok_r() handling	12 years ago
AP_Motors	Copter: add support for H-quad frame	12 years ago
AP_Mount	cleanup: use const for struct Location pointers and references	12 years ago
AP_Navigation	AP_Navigation: added a navigation controller class	12 years ago
AP_OpticalFlow	OpticalFlow: switch order of sin_yaw, cos_yaw	12 years ago
AP_Param	AP_Param: use const refs in a few more places	12 years ago
AP_PerfMon	AP_PerfMon: fixes to make it work under AP_HAL (almost)	12 years ago
AP_Progmem	Add AP_HAL_SMACCM implementation.	12 years ago
AP_RangeFinder	AP_RangeFinder: removed special case for APM1	12 years ago
AP_Relay	AP_Relay: fix pin used on APM2/SITL per Sando on drones-discuss	12 years ago
AP_Scheduler	AP_Scheduler: added SCHED_DEBUG=2	12 years ago
DataFlash	DataFlash: added Log_Write_Message()	12 years ago
Filter	Add AVR compatibility header for missing math.h definitions.	12 years ago
GCS_Console	build: change from Arduino.mk to apm.mk	12 years ago
GCS_MAVLink	GCS_MAVLink: typo in message definition	12 years ago
PID	libraries: replace constrain() with constrain_float()	12 years ago
RC_Channel	RC_Channel: support 8 auxillary RC channels	12 years ago
SITL	SITL: change default wind speed to zero	12 years ago
doc	…
memcheck	memcheck: fixed for PX4 build	12 years ago