initial commit for control commander

remote_control/aruco_estimator.py

@@ -3,12 +3,14 @@ import numpy as np
 import cv2
 import os
 import time
+import math
 
 from shapely.geometry import LineString
 from queue import Queue
 
 import aruco
 
+
 class ArucoEstimator:
     corner_marker_ids = {
         'a': 0,
@@ -68,10 +70,6 @@ class ArucoEstimator:
 
         # create detector and get parameters
         self.detector = aruco.MarkerDetector()
-        # self.detector.setDictionary('ARUCO_MIP_36h12')
-        #self.detector.setDictionary('ARUCO_MIP_16h3')
-        # self.detector.setDictionary('ARUCO')
-        #self.detector.setDetectionMode(aruco.DM_NORMAL, 0.05)
         self.detector.setDetectionMode(aruco.DM_VIDEO_FAST, 0.05)
 
         self.detector_params = self.detector.getParameters()
@@ -87,18 +85,12 @@ class ArucoEstimator:
             self.camparam.readFromXMLFile(os.path.join(os.path.dirname(__file__), "realsense.yml"))
         else:
             self.camparam.readFromXMLFile(os.path.join(os.path.dirname(__file__), "dfk72_6mm_param2.yml"))
-        print(self.camparam)
 
-    def mouse_callback(self, event, px, py, flags, param):
-        """
-        This function is called for each mouse event inside the opencv window.
-        If there are reference markers available we compute the real world position corresponding to the clicked
-        position and put it in an event queue.
-        :param event: type of event (mouse movement, left click, right click, etc.)
-        :param px: x-position of event
-        :param py: y-position of event
-        """
-        if event == cv2.EVENT_LBUTTONDOWN:
+        self.drag_line_end = None
+        self.drag_line_start = None
+        self.previous_click = None
+
+    def compute_clicked_position(self, px, py):
         if self.all_corners_detected():
             # inter/extrapolate from clicked point to marker position
             px1 = self.corner_estimates['a']['pixel_coordinate'][0]
@@ -118,12 +110,50 @@ class ArucoEstimator:
 
             target_x = x1 + alpha * (x3 - x1)
             target_y = y1 + beta * (y3 - y1)
-                target = np.array([target_x, target_y, 0])
-
-                print(f"target = ({target_x},{target_y})")
-                self.event_queue.put(('click', target))
+            target = np.array([target_x, target_y])
         else:
             print("not all markers have been detected!")
+            target = np.array([px, -py])
+        return target
+
+    def mouse_callback(self, event, px, py, flags, param):
+        """
+        This function is called for each mouse event inside the opencv window.
+        If there are reference markers available we compute the real world position corresponding to the clicked
+        position and put it in an event queue.
+        :param event: type of event (mouse movement, left click, right click, etc.)
+        :param px: x-position of event
+        :param py: y-position of event
+        """
+        target = None
+
+        if event == cv2.EVENT_LBUTTONDOWN:
+            self.drag_line_start = (px, py)
+        elif event == cv2.EVENT_LBUTTONUP:
+            self.drag_line_end = (px, py)
+            target_pos = self.compute_clicked_position(self.drag_line_start[0], self.drag_line_start[1])
+            if self.drag_line_start != self.drag_line_end:
+                # compute target angle for clicked position
+                facing_pos = self.compute_clicked_position(px, py)
+                v = facing_pos - target_pos
+                target_angle = math.atan2(v[1], v[0])
+            else:
+                # determine angle from previously clicked pos (= self.drag_line_end)
+                if self.previous_click is not None:
+                    previous_pos = self.compute_clicked_position(self.previous_click[0], self.previous_click[1])
+                    v = target_pos - previous_pos
+                    target_angle = math.atan2(v[1], v[0])
+                else:
+                    target_angle = 0.0
+
+            target = np.array([target_pos[0], target_pos[1], target_angle])
+            print(target)
+            self.previous_click = (px, py)
+            self.event_queue.put(('click', {'x': target[0], 'y': target[1], 'angle': target[2]}))
+            self.drag_line_start = None
+        elif event == cv2.EVENT_MOUSEMOVE:
+            if self.drag_line_start is not None:
+                self.drag_line_end = (px, py)
 
     def run_tracking(self, draw_markers=True, draw_marker_coordinate_system=False, invert_grayscale=False):
         """
@@ -132,6 +162,9 @@ class ArucoEstimator:
         cv2.namedWindow('RoboRally', cv2.WINDOW_AUTOSIZE)
         cv2.setMouseCallback('RoboRally', self.mouse_callback)
 
+        fps_display_rate = 1  # displays the frame rate every 1 second
+        fps_counter = 0
+        start_time = time.time()
         try:
             running = True
             while running:
@@ -157,16 +190,16 @@ class ArucoEstimator:
                 # extract data for detected markers
                 detected_marker_data = {}
                 for marker in detected_markers:
-                    detected_marker_data[marker.id] = {'marker_center': marker.getCenter()}
                     if marker.id >= 0:
+                        detected_marker_data[marker.id] = {'marker_center': marker.getCenter()}
+
                         if marker.id in self.corner_marker_ids.values():
-                            marker.calculateExtrinsics(0.1, self.camparam)
+                            marker.calculateExtrinsics(0.075, self.camparam)
                         else:
                             marker.calculateExtrinsics(0.07, self.camparam)
                         detected_marker_data[marker.id]['Rvec'] = marker.Rvec
                         detected_marker_data[marker.id]['Tvec'] = marker.Tvec
 
-                    if marker.id >= 0:  # draw markers onto the image
                         if draw_markers:
                             marker.draw(color_image, np.array([255, 255, 255]), 2, True)
 
@@ -182,6 +215,20 @@ class ArucoEstimator:
                     color_image = self.draw_grid_lines(color_image, detected_marker_data)
                 color_image = self.draw_robot_pos(color_image, detected_marker_data)
 
+                # draw drag
+                if self.drag_line_start is not None and self.drag_line_end is not None:
+                    color_image = cv2.line(color_image, self.drag_line_start, self.drag_line_end, color=(0, 0, 255), thickness=2)
+
+                # compute frame rate
+                fps_counter += 1
+                delta_t = time.time() - start_time
+                if delta_t > fps_display_rate:
+                    fps_counter = 0
+                    start_time = time.time()
+                color_image = cv2.putText(color_image, f"fps = {(fps_counter / delta_t):.2f}", (10, 25), cv2.FONT_HERSHEY_PLAIN, 2,
+                                          (0, 255, 255),
+                                          thickness=2)
+
                 # Show images
                 cv2.imshow('RoboRally', color_image)
                 key = cv2.waitKey(1)
@@ -192,7 +239,7 @@ class ArucoEstimator:
                         self.draw_grid = not self.draw_grid
                     if key == ord('q'):
                         running = False
-                    if key == ord('a'):
+                    if key == ord('x'):
                         color_sensor = self.pipeline.get_active_profile().get_device().query_sensors()[1]
                         if color_sensor.get_option(rs.option.enable_auto_exposure) == 1.0:
                             color_sensor.set_option(rs.option.enable_auto_exposure, False)
@@ -200,6 +247,8 @@ class ArucoEstimator:
                         else:
                             color_sensor.set_option(rs.option.enable_auto_exposure, True)
                             print("auto exposure ON")
+                    if key == ord('i'):
+                        invert_grayscale = not invert_grayscale
         finally:
             cv2.destroyAllWindows()
             if self.pipeline is not None:
@@ -244,7 +293,7 @@ class ArucoEstimator:
             _, _, _, _, _, _, euler_angles = cv2.decomposeProjectionMatrix(pose_mat)
             angle = -euler_angles[2][0] * np.pi / 180.0
 
-            self.robot_marker_estimates[marker_id] = {'t': t_image, 'x': x, 'y': y, 'angle': angle}
+            self.robot_marker_estimates[marker_id] = {'t': float(t_image), 'x': float(x), 'y': float(y), 'angle': float(angle)}
 
     def all_corners_detected(self):
         # checks if all corner markers have been detected at least once

remote_control/control_commander.py

@@ -0,0 +1,80 @@
+import numpy as np
+import time
+
+from robot import ControlledRobot
+from pid_controller import PIDController
+from event_listener import EventListener
+
+
+class CommanderBase:
+    def __init__(self):
+        self.robots = []
+        self.robots = [ControlledRobot(12, '10.10.11.91')]  # , Robot(13, '192.168.1.13'), Robot(14, '192.168.1.14')]
+        # self.robots = [ControlledRobot(marker_id=13, ip='10.10.11.90'),
+        # ControlledRobot(marker_id=14, ip='10.10.11.89')]
+
+        for r in self.robots:
+            r.connect()
+            r.attach_controller(PIDController())
+
+        self.event_listener = EventListener(event_server=('127.0.0.1', 42424))
+
+        self.current_robot_index = 0
+        self.controlling = False
+        self.running = False
+
+    def run(self):
+        unconnected_robots = list(filter(lambda r: not r.connected, self.robots))
+        if len(unconnected_robots) > 0:
+            print(f"warning: could not connect to the following robots: {unconnected_robots}")
+            return
+
+        all_detected = False
+        while not all_detected:
+            undetected_robots = list(filter(lambda r: None in r.get_measurement(), self.robots))
+            all_detected = len(undetected_robots) == 0
+            if not all_detected:
+                print(f"warning: no measurements available for the following robots: {undetected_robots}")
+                time.sleep(0.5)
+
+        print("starting control")
+        self.running = True
+        while self.running:
+            while not self.event_listener.event_queue.empty():
+                event = self.event_listener.event_queue.get()
+                self.handle_event(event)
+
+    def handle_event(self, event):
+        # handle events from opencv window
+        print("event: ", event)
+        if event[0] == 'click':
+            target = event[1]
+            target_pos = np.array([target['x'], target['y'], target['angle']])
+            self.robots[self.current_robot_index].move_to_pos(target_pos)
+        elif event[0] == 'key':
+            key = event[1]
+            if key == 32:  # arrow up
+                self.controlling = not self.controlling
+                if not self.controlling:
+                    print("disable control")
+                    for r in self.robots:
+                        r.stop_control()
+                else:
+                    print("enable control")
+                    for r in self.robots:
+                        r.start_control()
+            elif key == 9:  # TAB
+                # switch controlled robot
+                self.current_robot_index = (self.current_robot_index + 1) % len(self.robots)
+                robot = self.robots[self.current_robot_index]
+                print(f"controlled robot: {robot.id}")
+            elif key == 113 or key == 27:  # q or ESCAPE
+                print("quit!")
+                for r in self.robots:
+                    r.stop_control()
+                self.running = False
+
+
+if __name__ == '__main__':
+    rc = CommanderBase()
+    rc.run()

remote_control/controller.py

@@ -0,0 +1,59 @@
+import threading
+import time
+
+
+class ControllerBase:
+    def __init__(self, control_rate=0.1):
+        self.robot = None
+        self.controlling = False
+        self.target_pos = None
+
+        self.control_thread = None
+        self.control_rate = control_rate
+
+    def control_loop(self):
+        while self.controlling:
+            if self.target_pos is not None:
+                state = self.get_measured_position()
+
+                control = self.compute_control(state)
+
+                self.apply_control(control)
+
+                time.sleep(self.control_rate)
+        self.apply_control((0.0, 0.0))   # stop robot
+
+    def set_target_position(self, target_pos):
+        self.target_pos = target_pos
+
+    def get_measured_position(self):
+        if self.robot is not None:
+            return self.robot.get_measurement()
+        else:
+            raise Exception("error: controller cannot get measurement!\n"
+                            "       there is no robot attached to the controller!")
+
+    def compute_control(self, state):
+        return 0.0, 0.0
+
+    def apply_control(self, control):
+        if self.robot is not None:
+            self.robot.send_cmd(u1=control[0], u2=control[1])
+        else:
+            raise Exception("error: controller cannot apply control!\n"
+                            "       there is no robot attached to the controller!")
+
+    def attach_robot(self, robot):
+        self.robot = robot
+
+    def start(self):
+        self.controlling = True
+        # start control thread
+        self.control_thread = threading.Thread(target=self.control_loop)
+        self.control_thread.start()
+
+    def stop(self):
+        # pause controller
+        self.controlling = False
+        if self.control_thread is not None:
+            self.control_thread.join()

remote_control/event_listener.py

@@ -0,0 +1,49 @@
+import socket
+import threading
+import queue
+import json
+
+
+class EventListener:
+    def __init__(self, event_server):
+        self.event_thread = threading.Thread(target=self.receive_events)
+        self.event_thread.daemon = True  # mark thread as daemon -> it terminates automatically when program shuts down
+        self.event_queue = queue.Queue()
+        self.receiving = False
+
+        # connect to event server
+        print(f"connecting to event server on {event_server} ...")
+        self.event_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  # TCP socket
+
+        try:
+            self.event_socket.connect(event_server)
+            self.event_socket.sendall(f"events\n".encode())
+
+            self.event_socket.settimeout(0.1)
+            # check if we receive data from the event server
+            response = self.event_socket.recv(1024)
+            if 'error' not in str(response):
+                print("... connected! -> start listening for events")
+                self.event_socket.settimeout(None)
+                # if so we start the event thread
+                self.event_thread.start()
+            else:
+                print(f"error: cannot communicate with the event server.\n       The response was: {response}")
+        except socket.timeout:
+            print(f"error: the event server did not respond.")
+        except ConnectionRefusedError:
+            print(f"error: could not connect to event server at {event_server}.")
+
+    def receive_events(self):
+        self.receiving = True
+        while self.receiving:
+            received = str(self.event_socket.recv(1024), "utf-8")
+            if len(received) > 0:
+                events = received.split('\n')
+                for event_json in events:
+                    if len(event_json) > 0:
+                        event = json.loads(event_json)
+                        self.event_queue.put(event)
+            else:
+                self.receiving = False
+        print("event server seems to have shut down -> stop listening")

remote_control/measurement_client.py

@@ -2,12 +2,14 @@ import socket
 
 HOST, PORT = "localhost", 42424
 
-robot_id = 11
+robot_id = 12
 
-# SOCK_DGRAM is the socket type to use for UDP sockets
-sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
-
-sock.sendto(f"{robot_id}\n".encode(), (HOST, PORT))
-while True:
+sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+sock.connect((HOST, PORT))
+sock.sendall(f"{robot_id}\n".encode())     # request data for robot with given id
+#sock.sendall(f"events\n".encode())        # request events
+receiving = True
+while receiving:
     received = str(sock.recv(1024), "utf-8")
     print("Received: {}".format(received))
+    receiving = len(received) > 0

remote_control/measurement_server.py

@@ -1,38 +1,60 @@
 import socketserver
 import threading
 import time
+import json
 
 from aruco_estimator import ArucoEstimator
 
 
 class MeasurementHandler(socketserver.BaseRequestHandler):
     def handle(self) -> None:
-        data = self.request[0]
-        socket = self.request[1]
+        data = self.request.recv(1024).strip()
+
         cur_thread = threading.current_thread()
         print(f"current thread {cur_thread}")
+
+        if 'events' in data.decode():
+            self.request.sendall('subscribed to events\n'.encode())
+            # send input events
+            while True:
+                while not self.server.estimator.event_queue.empty():
+                    event = self.server.estimator.event_queue.get()
+                    self.request.sendall((json.dumps(event) + '\n').encode())
+                    self.server.estimator.last_event = None
+                time.sleep(1.0 / self.server.max_measurements_per_second)
+
+        else:
+            # send robot position
             try:
                 marker_id = int(data)
+            except ValueError:
+                marker_id = None
+
+            if marker_id is not None:
                 if marker_id in self.server.estimator.robot_marker_estimates:
                     while True:
-                    socket.sendto(f"{self.server.estimator.robot_marker_estimates[marker_id]}\n".encode(),
-                                  self.client_address)
+                        self.request.sendall((json.dumps(self.server.estimator.robot_marker_estimates[marker_id])
+                                              + '\n').encode())
                         time.sleep(1.0 / self.server.max_measurements_per_second)
                 else:
-                socket.sendto("error: unknown robot marker id\n".encode(),
-                              self.client_address)
-        except ValueError:
-            socket.sendto("error: data not understood. expected robot marker id (int)\n".encode(), self.client_address)
-
+                    self.request.sendall("error: unknown robot marker id\n".encode())
+            else:
+                self.request.sendall("error: data not understood. "
+                                     "expected <robot marker id (int)> or 'events'\n".encode())
         return
 
 
-class MeasurementServer(socketserver.ThreadingMixIn, socketserver.UDPServer):
+class MeasurementServer(socketserver.ThreadingMixIn, socketserver.TCPServer):
+    allow_reuse_address = True
+
     def __init__(self, server_address, RequestHandlerClass, estimator, max_measurements_per_second=30):
         super().__init__(server_address, RequestHandlerClass)
         self.estimator = estimator
         self.max_measurements_per_second = max_measurements_per_second
 
+    def handle_error(self, request, client_address):
+        print("an error occurred -> terminating connection")
+
 
 if __name__ == "__main__":
     aruco_estimator = ArucoEstimator(use_realsense=True, robot_marker_ids=[11, 12, 13, 14])
@@ -43,4 +65,4 @@ if __name__ == "__main__":
                            max_measurements_per_second=30) as measurement_server:
         measurement_server.serve_forever()
 
-    # receive with: nc 127.0.0.1 42424 -u  -> 15 + Enter
+    # receive with: nc 127.0.0.1 42424  -> 12 + Enter

remote_control/pid_controller.py

@@ -2,15 +2,17 @@ import numpy as np
 import math
 import time
 
+from controller import ControllerBase
 
-class PIDController:
-    def __init__(self, estimator):
-        self.t = time.time()
 
-        self.estimator = estimator
+class PIDController(ControllerBase):
+    def __init__(self):
+        super().__init__()
+        self.t = None
+
         self.controlling = False
 
-        self.P_angle = 0.4     # PID parameters determined by Ziegler-Nichols. measured K_crit = 1.4, T_crit = 1.5
+        self.P_angle = 0.4
         self.I_angle = 0.35
         self.D_angle = 0.1
 
@@ -18,198 +20,53 @@ class PIDController:
         self.I_pos = 0.3
         self.D_pos = 0.1
 
-        self.mode = None
-
-    def move_to_pos(self, target_pos, robot, near_target_counter=5):
-        near_target = 0
-        while near_target < near_target_counter:
-            while not self.estimator.event_queue.empty():
-                event = self.estimator.event_queue.get()
-                print("event: ", event)
-                if event[0] == 'click':
-                    pass
-                elif event[0] == 'key':
-                    key = event[1]
-
-                    if key == 84:  # arrow up
-                        self.controlling = True
-                        self.t = time.time()
-                    elif key == 82:  # arrow down
-                        self.controlling = False
-                        robot.send_cmd()
-                    elif key == 48:  # 0
-                        target_pos = np.array([0.0, 0.0, 0.0])
-                    elif key == 43:  # +
-                        self.control_scaling += 0.1
-                        self.control_scaling = min(self.control_scaling, 1.0)
-                        print("control scaling = ", self.control_scaling)
-                    elif key == 45:  # -
-                        self.control_scaling -= 0.1
-                        self.control_scaling = max(self.control_scaling, 0.1)
-                        print("control scaling = ", self.control_scaling)
-                    elif key == 113:
-                        print("quit!")
-                        self.controlling = False
-                        robot.send_cmd()
-                        return
-                    elif key == 27:  # escape
-                        print("quit!")
-                        self.controlling = False
-                        robot.send_cmd()
-                        return
-
-            x_pred = self.get_measurement(robot.id)
-
-            if x_pred is not None:
-                error_pos = np.linalg.norm(x_pred[0:2] - target_pos[0:2])
-                angles_unwrapped = np.unwrap([x_pred[2], target_pos[2]])  # unwrap angle to avoid jump in data
-                error_ang = np.abs(angles_unwrapped[0] - angles_unwrapped[1])
-                # print("error pos = ", error_pos)
-                # print("error_pos = {}, error_ang = {}".format(error_pos, error_ang))
-
-                # if error_pos > 0.075 or error_ang > 0.35:
-                if error_pos > 0.05 or error_ang > 0.1:
-                    # solve mpc open loop problem
-                    res = self.ols.solve(x_pred, target_pos)
-
-                    # us1 = res[0]
-                    # us2 = res[1]
-                    us1 = res[0] * self.control_scaling
-                    us2 = res[1] * self.control_scaling
-                    # print("u = {}", (us1, us2))
-
-                    # print("---------------- mpc solution took {} seconds".format(tmpc_end - tmpc_start))
-                    dt_mpc = time.time() - self.t
-                    if dt_mpc < self.dt:  # wait until next control can be applied
-                        # print("sleeping for {} seconds...".format(self.dt - dt_mpc))
-                        time.sleep(self.dt - dt_mpc)
-                else:
-                    us1 = [0] * self.mstep
-                    us2 = [0] * self.mstep
-                    near_target += 1
-
-                # send controls to the robot
-                for i in range(0, self.mstep):  # option to use multistep mpc if len(range) > 1
-                    u1 = us1[i]
-                    u2 = us2[i]
-                    robot.send_cmd(u1, u2)
-                    if i < self.mstep:
-                        time.sleep(self.dt)
-                    self.t = time.time()  # save time the most recent control was applied
-            else:
-                print("robot not detected yet!")
-
-    def interactive_control(self, robots):
-        controlled_robot_number = 0
-        robot = robots[controlled_robot_number]
-
-        ts = []
-        angles = []
-
-        target_pos = np.array([0.0, 0.0, 0.0])
-        e_angle_old = 0.0
-        e_pos_old = 0.0
-
-        i = 0.0
-        i_angle = 0.0
-        i_pos = 0.0
-
-        t0 = time.time()
-
-        running = True
-        while running:
-            # handle events from opencv window
-            while not self.estimator.event_queue.empty():
-                event = self.estimator.event_queue.get()
-                print("event: ", event)
-                if event[0] == 'click':
-                    target_pos = event[1]
-                    i_angle = 0
-                    i_pos = 0
-                    e_pos_old = 0
-                    e_angle_old = 0
         self.mode = 'combined'
-                elif event[0] == 'key':
-                    key = event[1]
 
-                    if key == 32:  # arrow up
-                        self.controlling = not self.controlling
-                        if not self.controlling:
-                            print("disable control")
-                            robot.send_cmd()  # stop robot
-                            self.mode = None    # reset control mode
-                        else:
-                            print("enable control")
-                            i = 0
-                            self.t = time.time()
-                    elif key == 48:  # 0
-                        target_pos = np.array([0.0, 0.0, 0.0])  # TODO: use center of board for target pos
-                    elif key == 97:  # a
-                        self.mode = 'angle'
-                        e_angle_old = 0
-                        i = 0
-                        self.t = time.time()
-                    elif key == 99:  # c
+        self.e_angle_old = 0.0
+        self.e_pos_old = 0.0
+
+        self.i = 0.0
+        self.i_angle = 0.0
+        self.i_pos = 0.0
+
+    def set_target_position(self, target_pos):
+        super(PIDController, self).set_target_position(target_pos)
         self.mode = 'combined'
-                        e_angle_old = 0
-                        e_pos_old = 0
-                        i_angle = 0
-                        i_pos = 0
-                        self.t = time.time()
-                    elif key == 112:  # p
-                        self.mode = 'position'
-                        e_pos_old = 0
-                        i = 0
-                        self.t = time.time()
-                    elif key == 43: # +
-                        self.P_pos += 0.1
-                        print("P = ", self.P_angle)
-                    elif key == 45: # -
-                        self.P_pos -= 0.1
-                        print("P = ", self.P_angle)
-                    elif key == 9:  # TAB
-                        # switch controlled robot
-                        robot.send_cmd()  # stop current robot
-                        controlled_robot_number = (controlled_robot_number + 1) % len(robots)
-                        robot = robots[controlled_robot_number]
-                        print(f"controlled robot: {robot.id}")
-                    elif key == 113 or key == 27:  # q or ESCAPE
-                        print("quit!")
-                        self.controlling = False
-                        robot.send_cmd()
-                        return
+        self.e_angle_old = 0.0
+        self.e_pos_old = 0.0
 
-            if self.controlling:
+        self.i = 0.0
+        self.i_angle = 0.0
+        self.i_pos = 0.0
+
+    def compute_control(self, state):
         # measure state
-                x_pred = self.get_measurement(robot.id)
-                dt = self.t - time.time()
+        x_pred = state[1:]
 
+        if self.t is None:
+            dt = 0.1
+        else:
+            dt = time.time() - self.t
 
-
-                #print(f"x_pred = {x_pred}\ntarget = {target_pos}\nerror = {np.linalg.norm(target_pos - x_pred)}\n")
         if self.mode == 'angle':
             # compute angle such that robot faces to target point
-                    target_angle = target_pos[2]
-
-                    ts.append(time.time() - t0)
-                    angles.append(x_pred[2])
+            target_angle = self.target_pos[2]
 
             angles_unwrapped = np.unwrap([x_pred[2], target_angle])  # unwrap angle to avoid jump in data
 
             e_angle = angles_unwrapped[0] - angles_unwrapped[1]   # angle difference
             p = self.P_angle * e_angle
-                    # i += self.I * dt * e     # right Riemann sum
-                    i += self.I_angle * dt * (e_angle + e_angle_old)/2.0  # trapezoidal rule
-                    d = self.D_angle * (e_angle - e_angle_old)/dt
+            self.i += self.I_angle * dt * (e_angle + self.e_angle_old)/2.0  # trapezoidal rule
+            d = self.D_angle * (e_angle - self.e_angle_old)/dt
 
-                    u1 = p - i - d
+            u1 = p + self.i + d
             u2 = - u1
 
-                    e_angle_old = e_angle
+            self.e_angle_old = e_angle
 
         elif self.mode == 'combined':
             # compute angle such that robot faces to target point
-                    v = target_pos[0:2] - x_pred[0:2]
+            v = self.target_pos[0:2] - x_pred[0:2]
             target_angle = math.atan2(v[1], v[0])
 
             angles_unwrapped = np.unwrap([x_pred[2], target_angle])  # unwrap angle to avoid jump in data
@@ -219,10 +76,10 @@ class PIDController:
 
             if e_pos < 0.05:
                 self.mode = 'angle'
-                        e_angle_old = 0
-                        e_pos_old = 0
-                        i_angle = 0
-                        i_pos = 0
+                self.e_angle_old = 0
+                self.e_pos_old = 0
+                self.i_angle = 0
+                self.i_pos = 0
                 u1 = 0
                 u2 = 0
             else:
@@ -235,33 +92,25 @@ class PIDController:
                         e_angle += np.pi
 
                 p_angle = self.P_angle * e_angle
-                        i_angle += self.I_angle * dt * (e_angle + e_angle_old) / 2.0  # trapezoidal rule
-                        d_angle = self.D_angle * (e_angle - e_angle_old) / dt
+                self.i_angle += self.I_angle * dt * (e_angle + self.e_angle_old) / 2.0  # trapezoidal rule
+                d_angle = self.D_angle * (e_angle - self.e_angle_old) / dt
 
                 p_pos = self.P_pos * e_pos
-                        i_pos += self.I_pos * dt * (e_pos + e_pos_old) / 2.0  # trapezoidal rule
-                        d_pos = self.D_pos * (e_pos - e_pos_old) / dt
+                self.i_pos += self.I_pos * dt * (e_pos + self.e_pos_old) / 2.0  # trapezoidal rule
+                d_pos = self.D_pos * (e_pos - self.e_pos_old) / dt
 
                 if forward:
-                            print("forward")
-                            u1 = p_angle + p_pos - i_angle - i_pos - d_angle - d_pos
-                            u2 = - p_angle + p_pos + i_angle - i_pos + d_angle - d_pos
+                    u1 = p_angle + p_pos + self.i_angle + self.i_pos + d_angle + d_pos
+                    u2 = - p_angle + p_pos - self.i_angle + self.i_pos - d_angle + d_pos
                 else:
-                            print("backward")
-                            u1 = p_angle - p_pos - i_angle + i_pos - d_angle + d_pos
-                            u2 = - p_angle - p_pos + i_angle + i_pos + d_angle + d_pos
+                    u1 = p_angle - p_pos + self.i_angle - self.i_pos + d_angle - d_pos
+                    u2 = - p_angle - p_pos - self.i_angle - self.i_pos - d_angle - d_pos
 
-                        e_pos_old = e_pos
-                        e_angle_old = e_angle
+                self.e_pos_old = e_pos
+                self.e_angle_old = e_angle
 
         else:
             u1 = 0.0
             u2 = 0.0
-                #print(f"u = ({u1}, {u2})")
-                robot.send_cmd(u1, u2)
         self.t = time.time()  # save time when the most recent control was applied
-                time.sleep(0.1)
-
-
-    def get_measurement(self, robot_id):
-        return self.estimator.get_robot_state_estimate(robot_id)
+        return u1, u2

remote_control/robot.py

@@ -1,12 +1,19 @@
 import socket
+import threading
+import json
+
 
 class Robot:
-    def __init__(self, marker_id, ip):
+    def __init__(self, marker_id, ip, measurement_server=('127.0.0.1', 42424)):
         self.id = marker_id
-        self.pos = None
-        self.euler = None
+
+        self.t_last_measurement = None
+        self.x = None
+        self.y = None
+        self.angle = None
 
         self.ip = ip
+        self.port = 1234
         self.socket = socket.socket()
 
         # currently active control
@@ -15,18 +22,47 @@ class Robot:
 
         self.connected = False
 
+        self.measurement_server = measurement_server
+        self.measurement_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)  # TCP socket
+        self.measurement_thread = threading.Thread(target=self.receive_measurements)
+        # mark thread as daemon -> it terminates automatically when program shuts down
+        self.measurement_thread.daemon = True
+        self.receiving = False
+
     def connect(self):
         # connect to robot
         try:
-            print("connecting to robot {} with ip {} ...".format(self.id, self.ip))
-            self.socket.connect((self.ip, 1234))  # connect to robot
+            print(f"connecting to robot {self.ip} at {self.ip}:{self.port} ...")
+            self.socket.connect((self.ip, self.port))  # connect to robot
             print("connected!")
             self.connected = True
         except socket.error:
-            print("could not connect to robot {} with ip {}".format(self.id, self.ip))
+            print(f"error: could not connect to robot {self.id} at {self.ip}:{self.port}")
+
+        # connect to measurement server
+        print(f"connecting to measurement server on {self.measurement_server} ...")
+
+        try:
+            self.measurement_socket.connect(self.measurement_server)
+            self.measurement_socket.sendall(f"{self.id}\n".encode())
+
+            self.measurement_socket.settimeout(0.1)
+            # check if we receive data from the measurement server
+            response = self.measurement_socket.recv(1024)
+            if 'error' not in str(response):
+                print("... connected! -> start listening for measurements")
+                self.measurement_socket.settimeout(None)
+                # if so we start the measurement thread
+                self.measurement_thread.start()
+            else:
+                print(f"error: cannot communicate with the measurement server.\n       The response was: {response}")
+        except socket.timeout:
+            print(f"error: the measurement server did not respond with data.")
+        except ConnectionRefusedError:
+            print(f"error: could not connect to measurement server at {self.measurement_server}.")
 
     def send_cmd(self, u1=0.0, u2=0.0):
-        if self.socket:
+        if self.socket and self.connected:
             try:
                 self.socket.send(f'({u1},{u2})\n'.encode())
             except BrokenPipeError:
@@ -35,3 +71,60 @@ class Robot:
             except ConnectionResetError:
                 print(f"error: connection to robot {self.id} with ip {self.ip} lost")
                 pass
+        else:
+            print(f"error: robot {self.id} is not connected to {self.ip}")
+
+    def receive_measurements(self):
+        self.receiving = True
+        while self.receiving:
+            received = str(self.measurement_socket.recv(1024), "utf-8")
+            if len(received) > 0:
+                last_received = received.split('\n')[-2]
+                measurement = json.loads(last_received)
+                self.t_last_measurement = measurement['t']
+                self.x = measurement['x']
+                self.y = measurement['y']
+                self.angle = measurement['angle']
+            else:
+                self.receiving = False
+                print(f"measurement server stopped sending data for robot {self.id}")
+
+    def get_measurement(self):
+        return self.t_last_measurement, self.x, self.y, self.angle
+
+    def __str__(self):
+        connection_state = '' if self.connected else 'not'
+        state = self.get_measurement()
+        last_measurement = f'last measurement = {state}' if None not in state else 'no measurements available'
+        return f"Robot {self.id}: ip = {self.ip}:{self.port} ({connection_state} connected) " + last_measurement
+
+    def __repr__(self):
+        return str(self)
+
+
+class ControlledRobot(Robot):
+    def __init__(self, marker_id, ip):
+        super().__init__(marker_id, ip)
+        self.controller = None
+
+    def start_control(self):
+        if self.controller is not None:
+            self.controller.start()
+        else:
+            raise Exception("Error: Cannot start control: there is not controller attached to the robot!")
+
+    def stop_control(self):
+        if self.controller is not None:
+            self.controller.stop()
+        else:
+            raise Exception("Error: Cannot stop control: there is not controller attached to the robot!")
+
+    def attach_controller(self, controller):
+        self.controller = controller
+        self.controller.attach_robot(self)
+
+    def move_to_pos(self, target_pos):
+        if self.controller is not None:
+            self.controller.set_target_position(target_pos)
+        else:
+            raise Exception("Error: Cannot move to position: there is not controller attached to the robot!")