荘の学習メモ

Configuration:  The minimal configuration is to use only a gyro and accelerometer sensor. Considering the  electromagnetic interference, disable the magnetometer . Make sure to balance the propellers . [2] Make sure that the center of gravity is as close as possible to the center of thrust . Choose Generic 250 Racer airframe in QGC. Switch the estimator to local_position_estimator if no external position available. (ex: GPS, camera, etc.) Make sure to calibrate the ESCs. Control latency: Enable SYS_FMU_TASK to reduce latency. Disable SYS_USE_IO and attach the motors to the AUX pins instead. Enable One-Shot PWM output signal to reduce latency ( PWM_RATE =0) Filter tuning: Tune the low-pass filter on the gyro sensor data:  IMU_GYRO_CUTOFF . Tune the low-pass filter on the D-term:  MC_DTERM_CUTOFF . Step1: Active  high-rate logging profile ( SDLOG_PROFILE  parameter) Step2: T une the gyro filter  IMU_GYRO_CUTOFF  by increasing it in steps of 10 Hz

Definition: The PX4 position controller  consists of an outer   P   position-control loop and an inner   PID  velocity-control loop as shown in the following figure.  Usually in PX4,   position-control  represents the case where both loops are active while  velocity-control  refers to the case when only the velocity control loop is in use. Multicopter position controller [1] Here are some parameters you can set for realizing better control performance [3]. Make sure you have finished the basic PID tuning before tuning the parameters mentioned in this article. MPC_HOLD_DZ:   Deadzone of sticks where position hold is enabled. MPC_ACC_HOR_MAX :   Maximum horizontal acceleration for auto mode and for manual mode. MPC_ACC_HOR:  Acceleration for auto and for manual. MPC_DEC_HOR_SLOW:  Slow horizontal manual deceleration for manual mode. MPC_ACC_UP_MAX:  Maximum vertical acceleration in velocity controlled modes upward. MPC_ACC_DOWN_MAX:  Maximum vertical acceleration

Based on tips for tuning PX4 PID parameters written in my previous post [1] or even using the default values directly, you will be able to fly your vehicle freely in manual or stabilized flight mode.   However, if you are using an unique vehicle (usually assembly by yourself and only equipped with sensors you desire) and struggling for finding the best PID parameters for your applications. I think following 8 tips will help you to get ideal PID parameters.  This is the vehicle I made based on LHI QAV250 fiber frame, with TX2, high-speed camera, etc.[2]  Tip1:  Tuning order: Rate controller -> attitude controller -> position controller The PX4 controllers are layered [3], which means a higher-level controller passes its results to a lower-level controller. Thus the PID tuning needs to be done from lowest-level controller to highest-level controller. Tip2:  Check if  PWM_MIN  is set correctly. Remove propellers Arm the vehicle and lower the throttle to the minimu