Address already in use

[xander-2077]

Hi, Jeguzzi.

It's a great project and it provides a complete environment for playing robots virtually. But some problems occurred when I try to interact with the robot through the client library.

• After installing this repository and coppeliasim, I made an attempt to use python scripts to control the EP/S1 robot in coppeliasim. I dragged a EP robot to scene and modified the child script of it to

  function sysCall_init()
  local index = sim.getNameSuffix(nil)
  handle = simRobomaster.create_ep(index, "127.0.0.1/8", "RM0")    
  end

• Then I opened a terminator with

  ./test --ip=127.0.0.1 --prefix_len=8 --serial_number="RM0"

  The responce is

  [2023-02-10 19:00:27.856] [info] Initialized a robot with these optional modules: arm servo#0 servo#1 gripper gimbal camera ToF 
  [2023-02-10 19:00:27.856] [info] Created real time dummy robot that will run an update step every 0.05 s 
  app_id 
  [2023-02-10 19:00:27.856] [info] [Connection] Start listening on port 127.0.0.1:30030
  [2023-02-10 19:00:27.856] [info] [Commands] Start listening on 127.0.0.1:20020
  [2023-02-10 19:00:27.856] [info] Creating a TCP video streamer on 127.0.0.1:40921 @ 200000 bps
  [2023-02-10 19:00:27.856] [info] [Discovery] Start broadcasting to 127.0.0.1
  [2023-02-10 19:00:27.856] [info] Created a RobotMaster with serial number RM0***********
  [2023-02-10 19:00:27.856] [info] Start spinning

• Then I pressed play. The coppeliasim reported this error

  [/RoboMaster[0]@childScript:error] 3: in simRobomaster.create_ep@simExtRobomaster: bind: **Address already in use**
  stack traceback:
  [C]: in function 'simRobomaster-typecheck.create_ep'
  [string "/RoboMaster[0]@childScript"]:3: in function 'sysCall_init'

It seems that ip address was already in use. I am not familiar with the communications between two softwares even though I had google for it. Could you please tell me how can I solve it? Thank you!

Best wishes

[jeguzzi]

When you run ./test --ip=... you start a dummy simulation of a Robomaster, binding it to the provided IP. It's dummy as it does not reproduce the robot behavior/physics/sensors/... but only serves the same remote API. I added it for internal testing.

When you press start, you start a coppeliasim simulation of the robot you have added to the scene. With the default arguments, it will try to bind to the same address, therefore failing. It would work if you use different IPs. You don't need to run ./test to use coppeliasim: running both would simulate 2 robots.

[xander-2077]

Thanks for your prompt reply! I really confused the relationship between ./test script and coppeliasim. According to your instruction, I need to write a python script to control the robot in coppeliasim. Is it right?

[jeguzzi]

Right. The same you would do with a real robot: a Python script that uses the RoboMaster SDK library, like this one https://github.com/jeguzzi/robomaster_sim/blob/main/examples/led.py.

[xander-2077]

Thanks a lot for your patient reply!