# Gripper Not Working in Mission Mode – Pixhawk 6C Mini + QGroundControl + PX4 v1.15.4

**URL:** <https://discuss.px4.io/t/gripper-not-working-in-mission-mode-pixhawk-6c-mini-qgroundcontrol-px4-v1-15-4/45605>\
**Category:** PX4 Autopilot\
**Created:** [May 16, 2025, 2:15pm UTC](https://discuss.px4.io/t/gripper-not-working-in-mission-mode-pixhawk-6c-mini-qgroundcontrol-px4-v1-15-4/45605 "2025-05-16T14:15:16Z")\
**Posts on this page:** 1\
**Showing post:** 1

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**Author:** ![camilo\_Sanabria](https://discuss.px4.io/user_avatar/discuss.px4.io/camilo_sanabria/32/19067_2.png) [@camilo\_Sanabria](https://discuss.px4.io/u/camilo_Sanabria)\
**Post date:** [May 16, 2025, 2:15pm UTC](https://discuss.px4.io/t/gripper-not-working-in-mission-mode-pixhawk-6c-mini-qgroundcontrol-px4-v1-15-4/45605/1 "2025-05-16T14:15:16Z")

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Hi everyone,  
I’m working on a payload drop system using a servo-controlled gripper in a FW drone, and I can’t get it to trigger in **mission mode** using PX4 and QGroundControl. I have the following settings.

- **Flight Controller:** Pixhawk 6C Mini
- **Firmware:** PX4 v1.15.4
- **Ground Station:** QGroundControl
- **Servo:** MG90S Metal Gear
- **Gripper Channel:** MAIN4 (mapped to “Gripper” in Actuator tab)
- **PWM Range:** 900–2000 µs
- **Power Supply:** External BEC
- **Mission Mode:** Drone is armed and flying when reaching the command

**This is working:**

- The servo works perfectly when tested manually from the **Actuator tab** in QGroundControl.
- The MAIN4 output is mapped to “Gripper”.
- Telemetry confirms the mission **reaches the Gripper Mechanism** command.

**This doesn’t work:**

- When the drone reaches the “Gripper Mechanism” item in mission mode, **no PWM signal is sent** , and the gripper does not activate.
- I tried using “Set Servo” instead, but QGroundControl gave this error on mission upload:

> **Mission transfer failed.  
> Error: Command is not supported. Item #12 Command: Set servo**

**Questions**

- Is **Gripper Mechanism** fully supported in PX4 v1.15.4 for Pixhawk 6C Mini?
- Should I use **Set Actuator** instead? If yes, how should I configure it and map the output correctly?
- Is there any other parameter I may have missed to enable mission-triggered PWM commands?

THANKS!!!

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_[View the full topic](https://discuss.px4.io/t/gripper-not-working-in-mission-mode-pixhawk-6c-mini-qgroundcontrol-px4-v1-15-4/45605)._