Killed or upon initial boot, servo's actuate to their extremes

Upon initial boot until I arm the aircraft or when I kill it with the transmitter switch, the servo’s will actuate to their very extremes in one direction. How do i fix this so they become neutral or unpowered when killed?

You can set the PWM Unarm length in the Parameters. No so shure if this is possible for the Kill Switch. Why is this a Problem and what Frame are you using? I assume a FW. Be aware that AFAIK you can only change thise Settings on a global Level affecting all Main PWM (respectively all AUX PWM) Outputs.

If I engage the kill switch it should kill the motors and servo’s. In some scenarios to prevent harm to people and the aircraft, having the ability to stop actuating the servo’s at the flick of a switch seems important. I’m using a custom VTOL platform. Both MC and FW mode act the same. Also, at power up it seems very unnecessary for the pixhawk to command all servo’s to their extremes.

Thanks for the advice though. I’ll try changing the PWM Unarm length and seeing if I get any different results.

How would you “Kill” the Servos. AFAIK Kill Switch will cut the PWM off so basically it is a 0 Signal. This probably very much depends on your Servos. At Power-Up first there is 0us PWM Signal, then when Powered there is the Preset PWM Value for Unarmed, and while Armed it is in the Range of PWM_MIN and PWM_MAX.

Found the problem. In the airframe init file, PWM_OUT was set to 12345678. Since my servo’s were on 5678, they were given a set pwm signal causing them to actuate to one side. Changing the PWM_OUT to 1234 solved my issue.

1 Like