Search found 23 matches
- Thu Mar 14, 2019 2:03 am
- Forum: General Discussion
- Topic: How fast can a Roboclaw process commands?
- Replies: 5
- Views: 5863
Re: How fast can a Roboclaw process commands?
It is the normal python driver but I've been placing every every attempt to communicate with the serial port in a try ... except block. Mostly comm failures are ok because the control loop will just cycles and we try again on a few milliseconds. With try-except we don't crash the program, we just lo...
- Tue Mar 12, 2019 2:17 pm
- Forum: General Discussion
- Topic: How fast can a Roboclaw process commands?
- Replies: 5
- Views: 5863
Re: How fast can a Roboclaw process commands?
Just as an aside, we can't send a long sequence of comands into a robot. The problem is that wheels slip and the wind vlows and the ground is not flat so we must continously measure where the robot is relative to the desired location and correct it. So we use IMU, GPA and cameras to track location w...
- Tue Mar 12, 2019 1:46 pm
- Forum: General Discussion
- Topic: RoboClaw 2x15A Motor Controller (V5E) - Freeze/Hang
- Replies: 2
- Views: 4131
Re: RoboClaw 2x15A Motor Controller (V5E) - Freeze/Hang
I see the same problem using ROS I get hangs and freezes. Then I added a write timeout and now get timeout exceptions. The problem might be in Py Serial. Without setting the write timeout i would hang "forever" but the timeout prevents that Here is my modification to roboclaw_driver.py (wr...
- Tue Mar 12, 2019 3:39 am
- Forum: General Discussion
- Topic: How fast can a Roboclaw process commands?
- Replies: 5
- Views: 5863
How fast can a Roboclaw process commands?
How fast can a Roboclaw process commands in serial packet mode over USB? I'm sure that must be a limit. Why do I ask? I'm using ROS and the "roboclaw_node" base controller node. This roboclaw_node, on it's own reads both encoders 10 times per seconds and also reads out all the diagnostic d...
- Tue Mar 12, 2019 3:06 am
- Forum: General Discussion
- Topic: Many intermittent failures with serial packet
- Replies: 5
- Views: 5941
Re: Many intermittent failures with serial packet
I am connecting the USB port on the roboclaw to the USB port on the Raspberry Pi3 using a short USB cable. My guess is that it should be reliable because USB uses differential signaling. Would it be more reliable to use the 5 volt serial pins on the roboclaw? But that means level converting the 3.3 ...
- Mon Mar 04, 2019 4:48 pm
- Forum: General Discussion
- Topic: Many intermittent failures with serial packet
- Replies: 5
- Views: 5941
Re: Many intermittent failures with serial packet
I have more information: The Roboclaw is hanging on writes. I changed the last function in roboclaw_driver.py to this: def Open(comport, rate): global port port = serial.Serial(comport, baudrate=rate, timeout=0.1, interCharTimeout=0.01, write_timeout=0.1) return The only change was to add "writ...
- Mon Mar 04, 2019 12:05 pm
- Forum: General Discussion
- Topic: Many intermittent failures with serial packet
- Replies: 5
- Views: 5941
Many intermittent failures with serial packet
Reading encoders values fails intermittently. I am using the ROS roboclaw_node Python node which makes calls to the python roboclaw driver. Specifically, it calls roboclaw.ReadEncM2() and roboclaw.ReadEncM1() 10 times per second. The Roboclaw is connected to a Raspberry Pi3b with a USB cable I notic...
- Sat Mar 02, 2019 6:49 pm
- Forum: General Discussion
- Topic: Roboclaw shuts down and needs power cycle
- Replies: 3
- Views: 4423
Roboclaw shuts down and needs power cycle
I'm using a Roboclaw 2x15A with the ROS driver and of course, in turn, it uses the python driver. I'm sending commands over USB from a Raspberry Pi3. Sometimes (I think) one of the two sides will detect an overcurrent and shut down. After that sending more command does nothing. The side not shut dow...
- Sat Mar 02, 2019 6:21 pm
- Forum: General Discussion
- Topic: Four motors?
- Replies: 1
- Views: 2727
Re: Four motors?
Yes, this is correct you can wire the motors in parallel. The motors will all run at the same speed as long as all of the wheels are firmly planted on the ground. But if a wheel "catches air" its motor will become unloaded and spin faster than the one that is still in contact with the grou...
- Fri Feb 15, 2019 3:02 pm
- Forum: General Discussion
- Topic: Roboclaw stops with all LEDs off, power cycle required
- Replies: 3
- Views: 4006
Re: Roboclaw stops with all LEDs off, power cycle required
How long do the LEDs flash on power up? On power up I see a green flash that lasts as long as a lightening bolt, not long enough to check of both green LEDs are lit or just one. It could also be that the green flash is so bright it overpowers the red flash. Is there some way to force the red LED to ...