Side of Drives Giving Out

[Al Skierkiewicz]

Leeland,
The Jags have an over current protection circuit that will remove motor drive for 3-4 seconds and flash the red LED on the face of the Jag. When a breaker trips open it resets almost immediately and there is a audible click. When repeatedly tripped it can cause a buzzing sound.
It is quite possible that over the months since build, hardware has loosened and mechanical parts have moved. This could cause friction in the drive that was not present earlier in the season.
Since you state that the robot can drive after a few seconds, my money is on the Jag over current protection.

Note: We had some CIM failures earlier this season. Upon inspecting the interior of the motors, we found that some of the winding wires had actually broken away from the commutator. These were older CIMs and had been put through some excessive driving. I believe that the overheated motors weakened the copper at stress points and caused the cracks. I posted pictures in a different thread earlier this year.

[Nick Lawrence]

Originally Posted by jwfoss

I'll even come over and help you out in the morning when I get there if you need it.

I'll be available to help too, if you need it.

-Nick

[LeelandS]

Originally Posted by Al Skierkiewicz

Leeland,
The Jags have an over current protection circuit that will remove motor drive for 3-4 seconds and flash the red LED on the face of the Jag. When a breaker trips open it resets almost immediately and there is a audible click. When repeatedly tripped it can cause a buzzing sound.
It is quite possible that over the months since build, hardware has loosened and mechanical parts have moved. This could cause friction in the drive that was not present earlier in the season.
Since you state that the robot can drive after a few seconds, my money is on the Jag over current protection.

So if we are activating the current protection circuit in the jaguar, is that an issue that can be resolved by adding a second CIM to the drives?

I did notice a Jaguar flashing red when we lost driving ability, but I'm not sure if it was the Jaguar responsible for the drive motors. I'll check that Thursday. When testing, I'll also have someone watching the Jaguar for the right drive motor, to see what happens when that side fails.

I will also see if we can pull together and get an effort to perform maintenance on the mechanical parts to help adjust the friction in the drives.

Also, thank you very much, Justin and Nick! I really appreciate the offer. Our goal right now is to be able to show up to Ruckus and not need extensive repairs, so that's what we're working towards. I really do appreciate the offer, and I will let you know if we will need to take you up on it

[Al Skierkiewicz]

Leeland,
Adding a second CIM would help with sharing the load. The flashing LED on the Jag is the fault LED. It can be caused by a few items like over temp and under voltage as well as over current. Start by tipping the robot to one side and without power turned on see if you can easily rotate the wheels on one side and then the other. High friction would show up in this test. It is also possible that once you have the weight of the robot on one or more of the wheels, high friction results due to wheel bearing misalignment or failure.
I already described the over current condition. The under voltage condition can be caused by loose wire connections, bad crimp terminals or loose hardware on the main breaker, battery, or PD terminals. Generally, those last few would also show up as radio or Crio resets. In programming you can try adjusting motor speeds to a lower value to minimize over current.

[Chris is me]

On top of what Al said - It's dirty, but switching to Victors might do the trick if your drive is such an edge case that it started failing after a season of wear. The Jaguar over current time out is way too lenient.

Another benefit of gearing down the drive a little bit would be that if you're hitting the bridge at less than full speed, a geared down drive would go the same speed at a higher PWM command, resulting in more available motor power in addition to the increased torque of a higher gear reduction.

I'll echo Foss and Nick in offering you help at Ruckus if you need anything. We could probably spare a few CIM-U-LATORs and 775s if you're willing to take that gamble.

[Joe Ross]

Originally Posted by LeelandS

I did notice a Jaguar flashing red when we lost driving ability, but I'm not sure if it was the Jaguar responsible for the drive motors. I'll check that Thursday. When testing, I'll also have someone watching the Jaguar for the right drive motor, to see what happens when that side fails.

The jaguar will flash red quickly when you're going in reverse (normal) and flash red slowly in the fault condition

Originally Posted by Al Skierkiewicz

Leeland,
The under voltage condition can be caused by loose wire connections, bad crimp terminals or loose hardware on the main breaker, battery, or PD terminals. Generally, those last few would also show up as radio or Crio resets.

Also check the electrical connections directly on the jaguar and after the jaguar.

[kevin.li.rit]

In the past we have run extra CIM at the ruckus. They're usually pretty accepting of that.