Search found 19 matches

by felix
Thu May 20, 2021 12:41 am
Forum: General Discussion
Topic: Packet Serial Mode Latency Issues
Replies: 1
Views: 3723

Re: Packet Serial Mode Latency Issues

Hi, I'm not sure for the Jetson Nano, but on the Jetson Xavier AGX developper kit, the UART port of the GPIO is also used for connecting a serial terminal for debugging. This sends some data on the UART pins in adition to those you want to send to the robocalw. Therefore, the roboclaw receives a &qu...
by felix
Wed Apr 14, 2021 12:33 am
Forum: General Discussion
Topic: Roboclaw 2x7A M1 Driver Failure
Replies: 2
Views: 3931

Re: Roboclaw 2x7A M1 Driver Failure

Hi, It's rather strange. I see one simple test to start with : can you run the motor backward full speed without using the motor controller (just connecting it to some power supply)? If for some reason it can't turn backward (mechanical problem, special anti-return design, ...) then setting a negati...
by felix
Sat Mar 20, 2021 9:02 am
Forum: General Discussion
Topic: Help with home position
Replies: 2
Views: 2838

Re: Help with home position

WARNING : I never used a roboclaw Solo, and I haven't checked the voltage levels for the switch pin : you might need to use a level shifter or a voltage divider in order to avaoid to destroy you board One hack could be to transform the switch into a "virtual switch" that is only active onc...
by felix
Sat Mar 20, 2021 6:15 am
Forum: General Discussion
Topic: Motors getting hot while robot immobile
Replies: 3
Views: 3125

Re: Motors getting hot while robot immobile

No I wasn't using position control, at least not explicitly : I was using velocity control with velocity=0. Is velocity=0 equivalent to using position control with target equal to the position when the command is sent? The ground is perfectly flat and horizontal (office floor), so there is no force ...
by felix
Tue Mar 09, 2021 8:12 am
Forum: General Discussion
Topic: Motors getting hot while robot immobile
Replies: 3
Views: 3125

Motors getting hot while robot immobile

Hi, I just opened our robot (which was turned on but immobile for several hours), and realized that all 4 motors are quite hot (it's possible to touch them, but not for a long time). There was no slope (the robot was in our office). We use velocity control (so we were sending at 10Hz a command to se...
by felix
Thu Feb 25, 2021 1:33 am
Forum: General Discussion
Topic: Broken current sensor?
Replies: 2
Views: 2306

Re: Broken current sensor?

Thanks,
It is already quite high (at 14), but we will try at 20 to make sure
by felix
Thu Feb 25, 2021 1:32 am
Forum: General Discussion
Topic: [security issue] No encoder -> maximal speed
Replies: 3
Views: 2754

Re: [security issue] No encoder -> maximal speed

Hi, I agree that it is a "normal" behaviour on a PID controler. Still if no other precautions are taken, a disconnecting the encoders means the robot will drive full speed without taking without slowing down even if we start sending low velocities to slow down. The speed error limit seems ...
by felix
Mon Feb 22, 2021 9:05 am
Forum: General Discussion
Topic: Broken current sensor?
Replies: 2
Views: 2306

Broken current sensor?

Hi, we just mounted 2 2x60A roboclaws on a new robot (the hardware and configuration is exactly the same as before, where everything worked fine). One of the roboclaws work fine. For the second one, channel 1 works fine, but on channel 2 we have the following problem (all tests done through motionSt...
by felix
Mon Feb 22, 2021 8:19 am
Forum: General Discussion
Topic: [security issue] No encoder -> maximal speed
Replies: 3
Views: 2754

[security issue] No encoder -> maximal speed

Hi, I recently encountered a severe issue with the setVelocity commands : if for whatever reason the encoder is disconnected, then the velocity quickly increases (until 100% PWM I suppose). This behavior is quite dangerous : it means that in case of a failure of the encoder, the robot will go full s...
by felix
Mon Feb 22, 2021 8:08 am
Forum: General Discussion
Topic: Both roboclaws sudenly stop
Replies: 5
Views: 5913

Re: Both roboclaws sudenly stop

Hi, I reduced the python ros node to the strict minimum (just a main loop checking if the node is not asked to shut down, and a delay to keep a 10Hz rate), and I still had issues (the program got stuck for quite exactly 1 second each time). So I suppose there must be somewhere a mutex or an I/O comm...