Both roboclaws sudenly stop
Posted: Mon Dec 21, 2020 9:41 am
Hi,
I have some strange problem.
We are using 2 robots, each with 4 motors (one per wheel). We use 2 pieces of 2x60A roboclaws per robot (one for the front wheels, one for the back wheels). Those are communicating with a Linux computer (Jetson Xavier AGX developer kit), over the same serial output on the GPIO.
From time to time both roboclaw stop for a fraction of a second (ie all 4 motors stop at the same moment).
Do you have any idea where it might come from?
Some (maybe) useful infos:
- the motors are rather big (rated 24V 250W, in practice it can be more than the announced 10A)
- it happens at all speeds we tried (from very slow to a speed of over 1m/s for the robot)
- it also happens when the wheels are not attached to the motors (so nearly no load condition)
- we use the E-stop function. There is a 1k or 4.7k resistor to pull up the E-stop. We use an electro-mechanical relay to connect the E-top pin to ground when we press one of the emergency buttons.
- batteries are 7S Lipos (max voltage 29.6V, min = 20V at rest). There are voltages drops when aksing huge currents (for example when turning on the spot), however I would be surprised if that's the problem, because the cut-off voltage of the roboclaws is very low (12V), and the problem happens even at low speeds without wheels.
- on the second robot (the new one), the problem appears to be far more frequent : I would say about 3 times per minute on the new, against 0.5 - 1 time per minute for the first one.
- the delay between to cut-off of the wheels is tottaly unpredictable : it ranges (on the new robot) from a few second to 1-2 minutes
Do you have any ideas where it might come from?
Thanks a lot in advance
Best
Felix
I have some strange problem.
We are using 2 robots, each with 4 motors (one per wheel). We use 2 pieces of 2x60A roboclaws per robot (one for the front wheels, one for the back wheels). Those are communicating with a Linux computer (Jetson Xavier AGX developer kit), over the same serial output on the GPIO.
From time to time both roboclaw stop for a fraction of a second (ie all 4 motors stop at the same moment).
Do you have any idea where it might come from?
Some (maybe) useful infos:
- the motors are rather big (rated 24V 250W, in practice it can be more than the announced 10A)
- it happens at all speeds we tried (from very slow to a speed of over 1m/s for the robot)
- it also happens when the wheels are not attached to the motors (so nearly no load condition)
- we use the E-stop function. There is a 1k or 4.7k resistor to pull up the E-stop. We use an electro-mechanical relay to connect the E-top pin to ground when we press one of the emergency buttons.
- batteries are 7S Lipos (max voltage 29.6V, min = 20V at rest). There are voltages drops when aksing huge currents (for example when turning on the spot), however I would be surprised if that's the problem, because the cut-off voltage of the roboclaws is very low (12V), and the problem happens even at low speeds without wheels.
- on the second robot (the new one), the problem appears to be far more frequent : I would say about 3 times per minute on the new, against 0.5 - 1 time per minute for the first one.
- the delay between to cut-off of the wheels is tottaly unpredictable : it ranges (on the new robot) from a few second to 1-2 minutes
Do you have any ideas where it might come from?
Thanks a lot in advance
Best
Felix