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VESC 6 plus working but no servo response

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saspragkathos
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Joined: 2020-02-06 17:19
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VESC 6 plus working but no servo response

I am using a VESC 6 plus on a Traxxas RC Car. The software of the car is set up on a NVIDIA Jetson TX2. It was working very well till the Jetson died. The replacement of the Jetson just arrived. I set up all the software for the car but this time the motor is working but the servo isn't responding.

I have tried many different firmware versions (both VESC_default.bin & VESC_servooout.bin) but i have a problem and i cannot understand what's happening. 

I have sent PWM signal to the servo via an Arduino Uno and it responds perfectly also. So my servo isn't dead neither its cables. However, i cannot find a solution. Is there anyone that has the same problem or has a solution for me? Do i have to configure somehow the PPM signal of the VESC in order for my servo to respond? I thought that every firmware especially the latest versions support all the communication protocols of the VESC (USB, PPM, CAN etc.) Do i have to tweak something to correct it?

Shreeram2311
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Joined: 2024-12-20 03:44
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Hi saspragkathos,
Did you get the solution. I have the same problem:

I’m running a VESC 60 MK6 on firmware v6.xx with VESC‑Tool v2.05, connected over UART. In the App Settings → General tab, Enable Servo Output is set to True, and I can manually move the steering servo by sliding the control in the VESC‑Tool “Controls” view.

However, when I publish a Float64 message from ROS to /commands/servo/position,

(for example: rostopic pub /commands/servo/position std_msgs/Float64 "{data: 0.5}")

the servo does not move, even though I can see /sensors/servo_position_command echo back the same value.

My motor commands over UART (/commands/motor/speed) continue to work perfectly from ROS, so the serial link and ROS driver appear to be functioning normally.

In conclusion I cannot control the servo to steer the wheels using ROS but the motor commands work normally and I can steer the wheel through VESC Tool. Is it necessary to flash a custom servoout.bin (or similar) image to enable a dedicated UART‑servo app?
If so, where can I obtain the correct firmware build that includes standalone Servo Output support under UART?

RaghulShreeramSivakumaran