Gremsy Pixy U 3-Axis Gimbal

The Gremsy Pixy U is a 3-axis gimbal that can communicate with the flight controller using the MAVLink protocol, weighs 465g, and is compatible with a range of cameras for real-time video or mapping purposes. More specifications can be found here on the Gremsy website. The user manual is here.

Where to Buy

The Pixy U can be purchased from the Gremsy store

Connecting to the Autopilot

We recommend connecting the Gimbals’s COM2 port to one of the autopilot’s Serial/Telemetry ports like Telem2 as shown above.

Connect with a ground station and set the following parameters:

• MNT_TYPE to “4” for “SToRM32 MavLink”
• SERIAL2_BAUD to “115” for 115200 bps. “SERIAL2” can be replaced with another serial port (i.e. SERIAL1) depending upon the physical connection
• SERIAL2_PROTOCOL to 2 for “MAVLink2”
• SR2_EXTRA1 to 10
• SR2_POSITION to 10

The gimbal’s maximum angles can be set using these parameters:

• MNT_ANGMIN_ROL to -3000 to allow leaning left up to 30deg
• MNT_ANGMAX_ROL to 3000 to allow leaning right up to 30deg
• MNT_ANGMIN_TIL to -9000 to allow pointing 90deg down
• MNT_ANGMAX_TIL to 3000 to allow pointing 30deg up
• MNT_ANGMIN_PAN to -18000 to allow turning around to the left
• MNT_ANGMAX_PAN to 18000 to allow turning around to the right

To control the gimbal’s lean angles from a transmitter set:

• MNT_RC_IN_TILT to 6 to control the gimbal’s tilt (aka pitch angle) with the transmitter’s Ch6 tuning knob
• MNT_RC_IN_ROLL to some input channel number to control the gimbal’s roll angle
• MNT_RC_IN_PAN to some input channel number to control the gimbals’ heading

Gremsy’s instructions can be found below:

• How to setup Gremsy gimbal with Pixhawk Cube
• Control Gremsy Gimbal with Herelink & Cube

Configuring the Gimbal

The gimbal should work without any additional configuration but to improve performance you may need to adjust the gimbal’s gains to match the camera’s weight

• Download, install and run the gTune setup application
• Connect the gimbal to your Desktop PC using a USB cable
• Push the “CONNECTION” button on the left side of the window, then select the COM port and press “Connect”
• Select the “CONTROLS” tab and ensure “SYNC” is selected so the gimbal communicates with the autopilot using MAVLink
• Select the “STIFFNESS” tab and adjust the Tilt, Roll and Pan gains so that the gimbal holds the camera in position without shaking

Testing Controlling the Gimbal from RC

• Disconnect the USB cable connecting your PC to the gimbal
• Powerup the vehicle and gimbal
• Move the transmitter’s channel 6 tuning knob to its minimum position, the camera should point straight down
• Move the ch6 knob to maximum and the gimbal should point upwards

Note

The RC’s channel 6 input can be checked from Mission Planner’s Radio calibration page

Testing ROI

The ROI feature points the vehicle and/or camera to point at a target. This can be tested by doing the following:

• Ensure the vehicle has GPS lock
• If using the Mission Planner, go to the Flight Data screen and right-mouse-button-click on a point about 50m ahead of the vehicle (the orange and red lines show the vehicle’s current heading), select Point Camera Here and input an altitude of -50 (meters). The camera should point forward and then tilt down at about 45 degrees

Pilot control of the gimbal can be restored by setting up an auxiliary function switch to “Retract Mount” (i.e. RCx_OPTION = 27) and then move the switch to the lower position