Gripper moving by its own

Wondering if somebody has had same issue:
Gripper works fine from manual control.
Randomly it opens or closes a little bit, with no operator hands on control.
Sometimes moving several seconds.
Apart from this issue, system works fine.


What buttons on the Joystick Controller are you using to control the Gripper?


Thanks for answer
I use a flight stick and emulate an Xbox 360 controller.
Worked fine for over a year.
I have never had the problem in test bench, only offshore, so hard to error check.

Bo, I haven’t heard of this before.

It sounds like a loose connection somewhere in the system.

We can look at logs, but you will need to update some software to get logging output of the ‘aux’ ports. (email me about that ;))

Good idea @jwalser to check bad wire connection
Tried banging and shaking on gripper and on electronics tube, no movement.

Gripper moves sometimes when there is no pilot input at all
Duration of movement is between 0.1 and 2 seconds
Movement can be both opening and closing
If You during auto movement tries moving other direction, movement stops.
Driving thrusters hard makes movement appear more often and longer

Could it be spikes from power supply?
I have an onboard secondary switched powersupply
But if so, why do not the lights go on and off sometimes? Never happens.

Dropping You an email regarding logging possibilities.

I have the same issue with my manipulator arm. I observed that I had the dead band values on my controller a little low, so the problem was actually with the handheld controller starting to become sloppy. That and the manipulator servos struggle holding its own weight up when controlled on land. When I turned up the dead band values, everything became good, but I’m looking into replacing the controller in the future. For the record, I am using an xbox 360 controller.

If you have checked your wiring and power supply, and ou cannot find any errors there, perhaps the error is as simple as the one above. Either way, you should check the power usage under 1) no gripper input events, 2) during input events (e.g. continuous sinusoidal movement), and 3) right before and after you have stopped giving input to the gripper . If you have some plotting tool available, it would be easier to analyze the data (e.g. plot power consumption/voltage during movement of gripper and voltage during no movement of gripper and compare).