stretch losing touch with its programming

We added a new team this year and they decided to build the stretch bot design to start. They followed the instructions for the build, but every time they start driving, it works for maybe 5 minutes correctly then just spins around in circles. The claw doesn’t work and it won’t drive at all. Is this a programming issue?

First thing I’d check is the axle into the motor on the side that seems to stop. I’ve seen several teams find an axle is just barely in the motor. When they pick it up and set it down, it temporarily is set back into the motor. After driving for a bit, then the axle comes out of the motor. Hopefully it’s something simple like that.

they’ve tried that, they always push the axle back in first. it still just spinning around in a circle. When they sit the bot on its side to check motors, both sides are spinning correctly. we are just confused now. I thought it had something to do with the driven gear being the center gear of the three, but we rechecked the design online and that is how it is built.

To check the software side you can try to see if there’s any parts that needs to be updated on the motors, brain, or controller. Download the latest VEX OS Utility and run that on all the parts.

If that doesn’t work and you use RobotC, you can try the ‘Firmware Download’ icon from the toolbar.

Have you checked the motors individually? Turn the brain on. Go to Programs and press X. In “settings”, scroll down to device info and press the check. Then got to the first port you want to test. When you press the check again, only that motor will start. Pressing the check again will stop the motor. That might troubleshoot the claw, unless they are plugged into the wrong ports. Also make sure both drive motors are going the same direction.

The drive not working sounds like a physical problem to me. A cable gets pinched, the axle slips out, there is a piece in the way of the wheels, or the cable is coming out of one of the sockets?

Are you using the default program, or one you made yourself?

Hope that helps.

Also, when the controller loses connection the brain continues to do the last command given to it. So also make sure the brain is properly connected. Also,. If the program does not respond when you got the x then you may just have to pull the battery to reset the robot.

If there is any other information you could give us that would help. Robotc file, etc… And I also +1 to everything above.

Out of curiosity, what radios are you using? We have noticed occasional wonkiness similar to what you describe with the blue smart radios that disappears when using one of the other radio types.