Instruction set which describes the most fundamental moves for our purposes.

Imported Libraries

• time : Sleeping after TCP commands which need time to execute.
• socket : Python to UR Script communication.
• json : Reading data from board grid json file.
• math : Translation from TCP to board coordinate space.
• rtde_control : Controller needed for movement of TCP.

TCP

extends null

Handles movement of TCP relevant to our purposes. Stores information describing the game environment and characteristics of pieces.

class TCP:
    def __init__(self, 
                 T[] host_info = [HOSTNAME, HOST_PORT], 
                 float[] origin = [ORIGIN_X, ORIGIN_Y],
                 float[] TCP_orientation = [TCP_RX, TCP_RY, TCP_RZ], 
                 float[] rest_position = REST_LOCATION,
                 float[] dispense_position = DISPENSE_LOCATION,
                 float height = BOARD_HEIGHT, 
                 float trns_angle = ANGLE):
        
        self.controller = rtde_control.RTDEControlInterface(host_info[0])       # TCP Controller
        self.origin = origin            # Origin of coordinate system
        self.trns_angle = trns_angle    # Angle which coordinate system is 'rotated' by
        self.host_info = host_info      # Host name and port
        
        # TCP State Variables
        self.position = origin              # (m)
        self.velocity = 0.5                 # (m/s)
        self.acceleration = 0.3             # (m/s^2)
        self.orientation = TCP_orientation  # (rad)
        self.isMagnetized = False

        # Board Variables
        self.height = height                        # Height of chess board when measured relative to cobot's base (m)
        self.rest_position = rest_position          # Position which TCP can come to rest at (m)
        self.dispense_position = dispense_position  # Position which TCP can dispence pieces at (m)

        f = open("data\\setup.json", encoding="utf-8")  
        self.board_data = json.load(f)                     # Location of each chess square in board's coordinate space

        self.piece_heights = {                             # Heights of each piece (m)
            "king" : 0.0762,                                  
            "pawn" : 0.0356,                                  
            "rook" : 0.04,                                    
            "knight" : 0.0457,                                  
            "bishop" : 0.0559,                                  
            "queen" : 0.0686                                   
        }

        # Initialization
        self.controller.moveL(                                                            # Moves to board's origin
            [self.origin[0], 
             self.origin[1], 
             self.height + 0.15,
             self.orientation[0],
             self.orientation[1],
             self.orientation[2]],
             0.5,
             0.3
        )
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.connect((self.host_info[0], self.host_info[1]))
        sock.send(bytes("sec myProg():\\n\\tset_tool_voltage(0)\\nend\\nmyProg()\\n", "utf-8")) # Ensures magnet is off
        sock.close()
        sleep(0.2)
        

TCP.__translate()

Takes a position in the board's coordinate space, then translates it into the arm's coordinate space.

# Parameters
pos : float[]             # Position in board's coordinate space.

def __translate(self, pos):
        x_1 = pos[1] * math.cos(self.trns_angle) - pos[0] * math.sin(self.trns_angle)
        y_1 = pos[1] * math.sin(self.trns_angle) + pos[0] * math.cos(self.trns_angle)

        return [x_1 + self.origin[0], y_1 + self.origin[1]]

Mathematical Basis