Panther 1.2: Problem with USI output

Hardware
1

According to the Panther EMU manual, the Weipu SP1312/S9 (USI connector) should have a relay connected that toggles when the emergency stop button is hit or the EMU generates a general emergency stop state. Pin 1 should be a normally open connection with pin 2 and 3 being common and pin 4 normally closed (When the Panther is operating normally). However, when the emergency button is hit, the relay seems to not toggle state. Therefore the pins are still connected the same way as described before. Also the ROS topic regarding the Emergency stop state says it is triggered, irregardless of the actual state of the E-stop button. What could cause this relay to not toggle?

2

Hello @QafkaT,

I am not sure if I understood you correctly. You are saying that pins of USI are connected as in operating state, that is #1 is floating, and #4 is connected to #2 and #3 AND in the same time ROS topic says platform is in E-stop?

Have you previously used the USI contactor pins with high capacitance loads or in any other way that could drain a large current through the relay during switching5. ? The limit for this pin is 1A, higher current could cause arcing and therefore damage relays contacts. And this can cause the robot to get stuck in E-stop mode.

However, if I understood incorrectly at the beginning and the relays pins also indicate the e-stop state exactly like ROS topic, this may be due to an active factor triggering this state. In the manual in the Triggers chapter (EMU Configuration | Husarion) you can find possible reasons why unlocking the robot from the E-stop state is not possible. Quite often it happens that this is a switched off motor controller.

To better understand your problem, please answer the following questions:

  1. Does the connection between pins 1-4 correspond to the same robot state that the ROS topic returns (ros2 topic echo /panther/hardware/e_stop)?
  2. Can your code call ros2 service call /panther/hardware/e_stop_trigger std_srvs/srv/Trigger somewhere?
  3. Is the estop button released when trying to reset with the command ros2 service call /panther/hardware/e_stop_reset std_srvs/srv/Trigger?
  4. Can you provide the logs of panther driver (log to built-in computer and type docker compose logs?
3

We’ve run a couple more tests and now it seems like neither pin 1 nor pin 4 is connected to the common. We are having no problems with the ROS topics and are able to reset an e-stop state using the service. We did have an extention hooked up incorporating more relays for e-stop functionality to the USI output which also used some capacitors. We’ve since removed those capacitors and now no sparking occurs when a loose wire is used to simulate the closing of the USI relay during testing. We can also not hear an audible ‘click’ when the e-stop state is set or reset, what should be characteristic for a relay. This suggests to me that the USI relay has indeed failed. Is there a way to replace the USI associated relay on the board, through THT or SMT means? Or should a replacement board be requested?

4

Hello @QafkaT,
We will manage the replacement via email. Please contact me support@husarion.com with the topic “Panther 1.2 USI” and please include the serial number of your Panther in the mail.

Best regards,
Jakub Delicat,
Husarion Support