UNITY LINK / ARC

This is aimed towards anyone interested in how to link a 3D environment to the ARC software package... This example shows how to extract servo positions from the virtual model in Unity and send them to ARC.

a) Install Flask, which is a bit finicky, but just take your time and follow this tutorial to get Flask up and running!

https://timmyreilly.azurewebsites.net/python-flask-windows-development-environment-setup/

Once this is done, you did not only install Flask, but you also created your very first own local server...which is a great feeling, right?

b) Download the Unity App, its early alpha...so just let me know if anything is not working out as expected!!

https://we.tl/t-2K7T2SpaS1

c) Open ARC and create a new Python script...

Now, with all the prerequisites being sorted out you will just have to copy and paste this into your Python script! Change the line port = 'COM19' to the COM of your connected Serial Bus. And run the script...

from System.Net import HttpWebRequest
uri = "http://127.0.0.1:5000/get_positions";

from System.IO import StreamReader
import clr
clr.AddReference('System.Web.Extensions')
from System.Web.Script.Serialization import JavaScriptSerializer

port = 'COM19'
baud = 115200
#baud=1000000
COM.Close(port);
COM.Open(port, baud);

def readData():
  webRequest = HttpWebRequest.Create(uri)
  response = webRequest.GetResponse()
  streamReader = StreamReader(response.GetResponseStream())
  jsonData = streamReader.ReadToEnd()
  js = JavaScriptSerializer()
  dataDict = js.DeserializeObject(jsonData)
  return dataDict

def _command(servo_id, command,lbp,hbp,lbt,hbt):
    length = 7
    sum = (lbp+hbp+lbt+hbt)
    checksum = 255 - ((servo_id + length + command + sum) % 256)
    COM.Write(port,bytearray([
        0x55, 0x55, servo_id, length, command,lbp,hbp,lbt,hbt, checksum
    ]))

def move(servo_id, position, time=0):
    _command(
        servo_id, 1,
        lower_byte(position), higher_byte(position),
        lower_byte(time), higher_byte(time),
    )

def lower_byte(value):
    return int(value) % 256

def higher_byte(value):
    return int(value / 256) % 256

def moveServos():
  dataDict = readData()
  servo =(dataDict)
  for servo,position in enumerate(servo):
      move(servo+1,position,0)

while True:
  moveServos()

And copy and paste the following code into the file you created in step a) and run the script... You will get a message telling you, your server is up and running!

from flask import Flask, json ,request

servoArray = [500, 500, 500, 500, 500, 500, 500, 500, 500, 500, 500, 500, 500, 500]
startup = True

app = Flask(__name__)

@app.route('/set_positions/', methods=['GET','POST'])
def set_positions(position):
    position = str(position)
    global servoArray
    position = position[1:-1]
    servoArray = position.split(',')
    servoArray = list(map(int, servoArray))
    return json.dumps(servoArray)

@app.route('/get_positions', methods=['GET'])
def get_positions():
    return json.dumps(servoArray)

@app.route('/')
def index():
  return 'ARC REST Index Page'

if __name__ == '__main__':
    app.run()

Now just run the ZOE_2D.exe and control your virtual robot with a Gamepad or by using w,s,a,d and q,e on your keyboard!! Your real robot will update the servo positions in correspondence to the virtual robot!

If you are not having a real robot set up, you will still see the positions being updated in your server window! Also you can access the servo position updates in your browser http://127.0.0.1:5000/get_positions

If you would like to test this setup with  another servo configuration just change the following line in your Python script...

move(servo+1,position,0)

to

Servo.SetPosition(servo, position, 0);

Have fun testing...