安装固定飞控

The flight controller should be placed on the frame as close as possible to the centre-of-gravity (CoG), top-side up, and oriented so that the heading mark arrow points towards the front of the vehicle. Vibration isolation is often needed, and you should follow the manufacturer recommendations. If mounted in this way, no further PX4 configuration is required.

安装方向

Almost all Flight Controllers have a heading mark arrow (shown below). 飞控应该顶部朝上安装在机架上，并使箭头指向与载具的前向一致（在所有的飞行器机架：固定翼、多旋翼、垂直起降、地面载具等上都是如此）。

If the controller cannot be mounted in the recommended/default orientation due to physical constraints, you will need to configure the autopilot software with the orientation that you actually used: Flight Controller Orientation. 一部分型号的飞控板提供了内置的减振；另一些型号则提供了减振泡沫，垫在载具和飞控之间以起到减振作用。

Position

The flight controller should be placed on the frame as close as possible to the centre-of-gravity.

If you can't mount the controller in this position, then you should configure the following parameters to set offset relative to the CoG: EKF2_IMU_POS_X, EKF2_IMU_POS_Y, EKF2_IMU_POS_Z (for the default EKF2 estimator).

Note that if you don't set these offsets then EKF2 position/velocity estimates will be at the IMU location rather that at the CoG. This may result in undesirable oscillations, depending on how far away the IMU is from the CoG.

Details

Explanation To understand the impact of not setting these offsets, consider the case when the flight controller (IMU) is in front of the CoG, you're flying in position mode, and there is a forward pitching motion around the CoG. The altitude estimate will go down, because the IMU has in fact moved down. As a reaction, the altitude controller will give more thrust to compensate. The amplitude depends on how far the IMU is located from the CoG. It might be negligible, but it is still some unneeded control effort that is constantly applied. If the offsets are specified, a pure pitch motion would not create any change in the altitude estimate so there will be less parasitic corrections.

振动隔离

Flight Control boards with in-built accelerometers or gyros are sensitive to vibrations. Some boards include in-built vibration-isolation, while others come with mounting foam that you can use to isolate the controller from the vehicle.

Vibration damping foam

You should use the mounting strategy recommended in your flight controller documentation.

TIP

使用Flight Review进行日志分析 > 振动 解释如何检测振动水平是否可以接受。如果遇到了问题，振动隔离提供了一些可能的解决办法。