Home        Store        Docs        Blog

Gripper setup - servo issues


(Brett Hobson) #1

I’m attempting to integrate the Newton Gripper on an ROV running ArduSub 3.5.3 and QGroundControl v3.2.4-BlueRobotics-Rev6 per the instructions. The controller is an Xbox One and I’ve mapped buttons 0 and 3 (A and Y) to servo 3 max momentary and min momentary respectively. Upon pushing the buttons they’re highlighted on the joystick summary page. The shift key is disabled on both. On the pixlhawk side, no signal is being asserted on the bottom pin of the aux 3 output when measured with a DVM. When the gripper is plugged in nothing happens when either button is pushed. The voltage on the servo rail appears to be 5V. Has anyone ran into a similar issue? I can’t think of what to try next. Any ideas are appreciated.


(Daniel Heideman) #2

Hi Brett,

Have you updated the firmware on your ROV to the latest version? The instructions for doing this can be found here.

The servo_N_max_momentary and servo_N_min_momentary button functions are not implemented in older versions of ArduSub 3.5.3, meaning the ROV will not respond to the corresponding button presses even if you are running a compatible version of QGroundControl.


(Brett Hobson) #3

Yes. I followed those instructions and have tested the stable, beta, and dev versions of the firmware. None of them can seem to actuate the gripper.


(Kevin) #4

Hi @bhobson,

Can you try plugging into AUX Channels 1 or 2 and readjusting your button mapping for Servo 1 or 2? We check all the grippers for functionality before they leave our facility, but if you have something like a servo tester you can verify functionality without the Pixhawk so we can narrow down what might be going on with your installation.


(Brett Hobson) #5

Yes I did try all 3 channels with the same results. Do you have any experience plugging the pixlhawk directly into a computer to do servo testing? Otherwise I’ll get the amazon order rolling for the tester. Seems like a nice thing to have around.


(Brett Hobson) #6

I found the problem. The aux pin config in the parameters tab under BRD_PWM_COUNT was set to no PWMS. Once I set this to 4 PWMS everything worked as expected. Thanks for your help!


(Kevin) #7

Excellent troubleshooting, glad its fixed!