driver.py

#!/usr/bin/env python
import roslib; roslib.load_manifest('ur5_driver')
import time, sys, threading
import datetime
import socket
import struct
import SocketServer

import rospy
import actionlib
from sensor_msgs.msg import JointState
from control_msgs.msg import FollowJointTrajectoryAction

HOSTNAME='ur-xx'
HOSTNAME="10.0.1.20"
PORT=30001

MSG_OUT = 1
MSG_QUIT = 2
MSG_JOINT_STATES = 3
MSG_MOVEJ = 4
MSG_WAYPOINT_FINISHED = 5
MULT_jointstate = 1000.0
MULT_time = 1000000.0
MULT_blend = 1000.0

JOINT_NAMES = ['shoulder_pan_joint', 'shoulder_lift_joint', 'elbow_joint',
               'wrist_1_joint', 'wrist_2_joint', 'wrist_3_joint']

Q1 = [2.2,0,-1.57,0,0,0]
Q2 = [1.5,0,-1.57,0,0,0]
  

connected_robot = None
connected_robot_lock = threading.Lock()
connected_robot_cond = threading.Condition(connected_robot_lock)
pub_joint_states = rospy.Publisher('joint_states', JointState)
dump_state = open('dump_state', 'wb')

class EOF(Exception): pass

def log(s):
    print "[%s] %s" % (datetime.datetime.now().strftime('%Y-%m-%d %H:%M:%S.%f'), s)

def setConnectedRobot(r):
    global connected_robot, connected_robot_lock
    with connected_robot_lock:
        connected_robot = r
        connected_robot_cond.notify()

def getConnectedRobot(wait=False):
    with connected_robot_lock:
        if wait:
            while not connected_robot:
                connected_robot_cond.wait(0.5)
        return connected_robot

# Receives messages from the robot over the socket
class CommanderTCPHandler(SocketServer.BaseRequestHandler):
        
    def recv_more(self):
        more = self.request.recv(4096)
        if not more:
            raise EOF()
        return more

    def handle(self):
        self.socket_lock = threading.Lock()
        self.waypoint_finished_cb = None
        setConnectedRobot(self)
        #print "Handling a request"
        try:
            buf = self.recv_more()
            if not buf: return

            while True:
                #print "Buf:", [ord(b) for b in buf]

                # Unpacks the message type
                mtype = struct.unpack_from("!i", buf, 0)[0]
                buf = buf[4:]
                #print "Message type:", mtype

                if mtype == MSG_OUT:
                    # Unpacks string message, terminated by tilde
                    i = buf.find("~")
                    while i < 0:
                        buf = buf + self.recv_more()
                        i = buf.find("~")
                        if len(buf) > 2000:
                            raise Exception("Probably forgot to terminate a string: %s..." % buf[:150])
                    s, buf = buf[:i], buf[i+1:]
                    log("Out: %s" % s)

                elif mtype == MSG_JOINT_STATES:
                    while len(buf) < 3*(6*4):
                        buf = buf + self.recv_more()
                    state_mult = struct.unpack_from("!" + ("i"*3*6), buf, 0)
                    buf = buf[3*6*4:]
                    state = [s / MULT_jointstate for s in state_mult]

                    msg = JointState()
                    msg.header.stamp = rospy.get_rostime()
                    msg.name = JOINT_NAMES
                    msg.position = state[:6]
                    msg.velocity = state[6:12]
                    msg.effort = state[12:18]
                    pub_joint_states.publish(msg)
                elif mtype == MSG_QUIT:
                    print "Quitting"
                    raise EOF()
                elif mtype == MSG_WAYPOINT_FINISHED:
                    while len(buf) < 4:
                        buf = buf + self.recv_more()
                    waypoint_id = struct.unpack_from("!i", buf, 0)[0]
                    buf = buf[4:]
                    if self.waypoint_finished_cb:
                        self.waypoint_finished_cb(waypoint_id)
                else:
                    raise Exception("Unknown message type: %i" % mtype)

                if not buf:
                    buf = buf + self.recv_more()
        except EOF:
            print "Connection closed (command)"

    def send_quit(self):
        with self.socket_lock:
            self.request.send(struct.pack("!i", MSG_QUIT))
            
    def send_movej(self, waypoint_id, q, a=3, v=0.75, t=0, r=0):
        assert(len(q) == 6)
        buf = ''.join([struct.pack("!ii", MSG_MOVEJ, waypoint_id),
                       struct.pack("!iiiiii", *[MULT_jointstate * qq for qq in q]),
                       struct.pack("!ii", MULT_jointstate * a, MULT_jointstate * v),
                       struct.pack("!ii", MULT_time * t, MULT_blend * r)])
        with self.socket_lock:
            self.request.send(buf)

    def set_waypoint_finished_cb(self, cb):
        self.waypoint_finished_cb = cb
    

class TCPServer(SocketServer.TCPServer):
    allow_reuse_address = True  # Allows the program to restart gracefully on crash
    timeout = 5


# Waits until all threads have completed.  Allows KeyboardInterrupt to occur
def joinAll(threads):
    while any(t.isAlive() for t in threads):
        for t in threads:
            t.join(0.2)

# Returns the duration between moving from point (index-1) to point
# index in the given JointTrajectory
def get_segment_duration(traj, index):
    if index == 0:
        return traj.points[0].time_from_start.to_sec()
    return (traj.points[index].time_from_start - traj.points[index-1].time_from_start).to_sec()

class UR5TrajectoryFollower(object):
    def __init__(self, robot):
        self.robot = robot
        self.server = actionlib.ActionServer("follow_joint_trajectory",
                                             FollowJointTrajectoryAction,
                                             self.on_goal, self.on_cancel, auto_start=False)
        self.robot.set_waypoint_finished_cb(self.on_waypoint_finished)

        self.goal_handle = None
        self.first_waypoint_id = 10
        self.tracking_i = 0
        self.pending_i = 0
        self.goal_start_time = rospy.Time(0)

        self.following_lock = threading.Lock()

    def start(self):
        self.server.start()

    def on_goal(self, goal_handle):
        log("on_goal")
        if self.goal_handle:
            rospy.logerr("Already have a goal in progress!  Rejecting.  (TODO)")
            goal_handle.set_rejected()
            return

        # TODO: Verify that the goal has the correct joints.  Reorder if necessary

        with self.following_lock:
            self.goal_handle = goal_handle
            self.tracking_i = 0
            self.pending_i = 0
            self.goal_start_time = rospy.get_rostime()

            # Sends a tracking point and a pending point to the robot
            self.goal_handle.set_accepted()
            traj = self.goal_handle.get_goal().trajectory
            # TODO: joints may have a different order
            self.robot.send_movej(self.first_waypoint_id, traj.points[0].positions,
                                  t=get_segment_duration(traj, 0))
            self.robot.send_movej(self.first_waypoint_id + 1, traj.points[1].positions,
                                  t=get_segment_duration(traj, 1))
            self.tracking_i = 0
            self.pending_i = 1

    def on_cancel(self):
        log("on_cancel")
        print "TODO: on_cancel"

    # The URScript program sends back waypoint_finished messages,
    # which trigger this callback.
    def on_waypoint_finished(self, waypoint_id):
        log("Waypoint finished: %i" % waypoint_id)
        index = waypoint_id - self.first_waypoint_id
        if index != self.tracking_i:
            rospy.logerr("Completed waypoint %i (id=%i), but tracking %i (id=%i)" % \
                         (index, waypoint_id, self.tracking_i,
                          self.first_waypoint_id + self.tracking_i))
            # TODO: Probably need to fail here

        traj = self.goal_handle.get_goal().trajectory
        traj_len = len(traj.points)
        
        # Checks if we've completed the trajectory
        if index == traj_len - 1:
            self.goal_handle.set_succeeded()
            self.first_waypoint_id += traj_len
            self.goal_handle = None

        # Moves onto the next segment
        self.tracking_i += 1
        if self.pending_i + 1 < traj_len:
            self.pending_i += 1
            # TODO: reorder joint positions
            self.robot.send_movej(self.first_waypoint_id + self.pending_i,
                                  traj.points[self.pending_i],
                                  t=get_segment_duration(traj, self.pending_i))
        

sock = None
def main():
    global sock
    rospy.init_node('ur5_driver', disable_signals=True)

    # Sends the program to the robot
    sock = socket.create_connection((HOSTNAME, PORT))
    with open('prog') as fin:
        sock.sendall(fin.read())

    server = TCPServer(("", 50001), CommanderTCPHandler)

    thread_commander = threading.Thread(name="CommanderHandler", target=server.handle_request)
    thread_commander.daemon = True
    thread_commander.start()

    r = getConnectedRobot(wait=True)
    print "Robot connected"

    action_server = UR5TrajectoryFollower(r)
    action_server.start()

    try:

        #log("movej Q1")
        #r.send_movej(1, Q1, t=2.0)
        #log("movej Q2")
        #r.send_movej(2, Q2, t=1.0)
        #time.sleep(3)

        #r.send_quit()

        # Waits for the threads to finish
        joinAll([thread_commander])
    except KeyboardInterrupt:
        r.send_quit()
        rospy.signal_shutdown("KeyboardInterrupt")
        raise

    '''
    print "Dump"
    print "="*70
    o = ""
    while len(o) < 4096:
        r = sock.recv(1024)
        if not r: break
        o = o + r
    print o
    '''
        

if __name__ == '__main__': main()