150 lines
6.0 KiB
Python
150 lines
6.0 KiB
Python
import socket
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import threading
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import json
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import numpy as np
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import time
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import math
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class Robot:
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def __init__(self, marker_id, ip, measurement_server=('127.0.0.1', 42424)):
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self.id = marker_id
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self.t_last_measurement = None
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self.x = None
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self.y = None
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self.angle = None
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self.ip = ip
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self.port = 1234
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self.socket = socket.socket()
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# currently active control
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self.u1 = 0.0
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self.u2 = 0.0
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self.connected = False
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self.measurement_server = measurement_server
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self.measurement_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) # TCP socket
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self.measurement_thread = threading.Thread(target=self.receive_measurements)
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# mark thread as daemon -> it terminates automatically when program shuts down
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self.measurement_thread.daemon = True
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self.receiving = False
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def connect(self):
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# connect to robot
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try:
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print(f"connecting to robot {self.ip} at {self.ip}:{self.port} ...")
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self.socket.connect((self.ip, self.port)) # connect to robot
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print("connected!")
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self.connected = True
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except socket.error:
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print(f"error: could not connect to robot {self.id} at {self.ip}:{self.port}")
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# connect to measurement server
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print(f"connecting to measurement server on {self.measurement_server} ...")
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try:
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self.measurement_socket.connect(self.measurement_server)
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self.measurement_socket.sendall(f"{self.id}\n".encode())
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self.measurement_socket.settimeout(0.1)
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# check if we receive data from the measurement server
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response = self.measurement_socket.recv(1024)
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if 'error' not in str(response):
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print("... connected! -> start listening for measurements")
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self.measurement_socket.settimeout(None)
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# if so we start the measurement thread
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self.measurement_thread.start()
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else:
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print(f"error: cannot communicate with the measurement server.\n The response was: {response}")
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except socket.timeout:
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print(f"error: the measurement server did not respond with data.")
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except ConnectionRefusedError:
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print(f"error: could not connect to measurement server at {self.measurement_server}.")
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def send_cmd(self, u1=0.0, u2=0.0):
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if self.socket and self.connected:
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try:
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self.socket.send(f'({u1},{u2})\n'.encode())
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except BrokenPipeError:
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print(f"error: connection to robot {self.id} with ip {self.ip} lost")
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pass
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except ConnectionResetError:
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print(f"error: connection to robot {self.id} with ip {self.ip} lost")
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pass
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else:
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print(f"error: robot {self.id} is not connected to {self.ip}")
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def receive_measurements(self):
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self.receiving = True
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while self.receiving:
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received = str(self.measurement_socket.recv(1024), "utf-8")
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if len(received) > 0:
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last_received = received.split('\n')[-2]
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measurement = json.loads(last_received)
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self.t_last_measurement = measurement['t']
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self.x = measurement['x']
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self.y = measurement['y']
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self.angle = measurement['angle']
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else:
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self.receiving = False
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print(f"measurement server stopped sending data for robot {self.id}")
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def get_measurement(self):
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return self.t_last_measurement, self.x, self.y, self.angle
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def __str__(self):
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connection_state = '' if self.connected else ' not'
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state = self.get_measurement()
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last_measurement = f'last measurement = {state}' if None not in state else 'no measurements available'
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return f"Robot {self.id}: ip = {self.ip}:{self.port} ({connection_state} connected ) " + last_measurement
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def __repr__(self):
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return str(self)
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class ControlledRobot(Robot):
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def __init__(self, marker_id, ip):
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super().__init__(marker_id, ip)
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self.controller = None
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def start_control(self):
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if self.controller is not None:
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self.controller.start()
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else:
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raise Exception("Error: Cannot start control: there is not controller attached to the robot!")
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def stop_control(self):
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if self.controller is not None:
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self.controller.stop()
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else:
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raise Exception("Error: Cannot stop control: there is not controller attached to the robot!")
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def attach_controller(self, controller):
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self.controller = controller
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self.controller.attach_robot(self)
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def move_to_pos(self, target_pos, blocking=False):
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if self.controller is not None:
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if not blocking:
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self.controller.set_target_position(target_pos)
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else: # only return after the robot has reached the target
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self.stop_control()
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self.controller.set_target_position(target_pos)
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self.start_control()
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close_to_target = False
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while not close_to_target:
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current_pos = np.array([self.x, self.y, self.angle])
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v = target_pos - current_pos
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angles_unwrapped = np.unwrap([current_pos[2], target_pos[2]]) # unwrap angle to avoid jump in data
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e_angle = angles_unwrapped[0] - angles_unwrapped[1] # angle difference
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e_pos = np.linalg.norm(v[0:2])
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print(f"e_pos = {e_pos}, e_ang = {e_angle}")
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close_to_target = e_pos < 0.05 and abs(e_angle) < 0.1
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time.sleep(0.1)
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print("target reached!")
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self.stop_control()
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else:
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raise Exception("Error: Cannot move to position: there is not controller attached to the robot!") |