直升机提示
- 一定要遵守维基指令,一步一步!
- 确保CG与主转轴一致
- 刀片跟踪必须在四分之一刀片厚度内,或更好地避免过度振动
- 震动是直升机自动驾驶的敌人!
- 内部燃烧引擎和涡轮可以产生VIBE日志中不出现的的联系高频振动,并且可以化执行其低频,从而影响EKF和姿态控制(见下文地面测试来检查这一点). 电动直升机也经常出现这种情况。
- 自动驾驶器应当隔离良好的振动. 建议使用自动驾驶装置,安装内部的IMU振动坝盖和减少振动装置。
- 传统直升机这是能够逆向飞行并使用完全负集体范围。
检查高频振动
在这方面的高ء频率振动是指接近IMU采样频率的振动,或其倍数,这些振带来的好处会与姿态总的说来器的控制输入量同名化. 高频振动的症状可能是,尽管飞行员正在以 你干嘛稳定的方式指挥水平飞行,但姿态估计会变得不正确,使其显著倾斜. 在极端,它可以导致电子安全 or even a crash. Excessive vibration can also make altitude hold imprecise or even produce uncontrollable climbs/descents.
One method of testing this, is to secure the helicopter to the ground, and run up the main rotor, watching the artificial horizon in the ground control station. If it moves away from level, you probably have a vibration issue which needs to be addressed. Testing should be done at various collective levels and rotor speeds. Be careful not to over-stress the helicopter with collective extremes.
Setup for ground test:
- Secure vehicle to the ground.
- Temporarily reduce Roll, Pitch, and Yaw P,I,and D, PIDs to zero. Be sure to restore them after this test!
- Set ACRO_OPTIONS = 2, temporarily, if not being used already.
- Change to ACRO mode.
- Arm and engage motor interlock, allowing the vehicle to spool up at 0 degree pitch, watching for any change from level in the GSC of the artificial horizon. Any significant tilt indicates noise is disrupting the attitude estimate and should be investigated and eliminated.
- Change the target main rotor speed a bit above and below the nominal target using the H_RSC_SETPOINT (or TX throttle curve if using Passthru mode) and repeat.
- Re-check the blade tracking also while doing this test.
Be sure to also eliminate the possibility of lower frequency vibrations from the main or tail rotors causing the issue. Unlike vibrations near the sampling rate and its harmonics, which cannot be eliminated by software filtering, rotor vibrations can be improved using ArduPilot's notch filtering feature. See common-measuring-vibration and Helicopter Dynamic Notch Filter Setup.
Possible False Landing Detections
Under extreme circumstances (flying in extremely turbulent conditions, for example), it is possible for the firmware, to falsely detect a landing condition, although still flying. This can lead to lack of control in position control modes and even possible disarming. An RC Auxiliary Function ("159") is provided to allow an RC to enable (needed when actually landing) or disable (to prevent false detects during missions) the landing detection algorithm under pilot control.
【本页后半部分仍为英文原文摘录，补译中。】
译自 ArduPilot Copter「Traditional Helicopter Tips」· 查看原文 · CC BY-SA 3.0