libardrone.py

# Copyright (c) 2011 Bastian Venthur
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
# THE SOFTWARE.


"""
Python library for the AR.Drone.

This module was tested with Python 2.6.6 and AR.Drone vanilla firmware 1.5.1.
"""


import socket
import struct
import sys
import threading
import multiprocessing

import arnetwork


__author__ = "Bastian Venthur"


ARDRONE_NAVDATA_PORT = 5554
ARDRONE_VIDEO_PORT = 5555
ARDRONE_COMMAND_PORT = 5556


class ARDrone(object):
    """ARDrone Class.

    Instanciate this class to control your drone and receive decoded video and
    navdata.
    """

    def __init__(self):
        self.seq_nr = 1
        self.timer_t = 0.2
        self.com_watchdog_timer = threading.Timer(self.timer_t, self.commwdg)
        self.lock = threading.Lock()
        self.speed = 0.2
        self.at(at_config, "general:navdata_demo", "TRUE")
        self.video_pipe, video_pipe_other = multiprocessing.Pipe()
        self.nav_pipe, nav_pipe_other = multiprocessing.Pipe()
        self.com_pipe, com_pipe_other = multiprocessing.Pipe()
        self.network_process = arnetwork.ARDroneNetworkProcess(nav_pipe_other, video_pipe_other, com_pipe_other)
        self.network_process.start()
        self.ipc_thread = arnetwork.IPCThread(self)
        self.ipc_thread.start()
        self.image = ""
        self.navdata = dict()
        self.time = 0

    def takeoff(self):
        """Make the drone takeoff."""
        self.at(at_ftrim)
        self.at(at_config, "control:altitude_max", "20000")
        self.at(at_ref, True)

    def land(self):
        """Make the drone land."""
        self.at(at_ref, False)

    def hover(self):
        """Make the drone hover."""
        self.at(at_pcmd, False, 0, 0, 0, 0)

    def move_left(self):
        """Make the drone move left."""
        self.at(at_pcmd, True, -self.speed, 0, 0, 0)

    def move_right(self):
        """Make the drone move right."""
        self.at(at_pcmd, True, self.speed, 0, 0, 0)

    def move_up(self):
        """Make the drone rise upwards."""
        self.at(at_pcmd, True, 0, 0, self.speed, 0)

    def move_down(self):
        """Make the drone decent downwards."""
        self.at(at_pcmd, True, 0, 0, -self.speed, 0)

    def move_forward(self):
        """Make the drone move forward."""
        self.at(at_pcmd, True, 0, -self.speed, 0, 0)

    def move_backward(self):
        """Make the drone move backwards."""
        self.at(at_pcmd, True, 0, self.speed, 0, 0)

    def turn_left(self):
        """Make the drone rotate left."""
        self.at(at_pcmd, True, 0, 0, 0, -self.speed)

    def turn_right(self):
        """Make the drone rotate right."""
        self.at(at_pcmd, True, 0, 0, 0, self.speed)

    def reset(self):
        """Toggle the drone's emergency state."""
        self.at(at_ref, False, True)
        self.at(at_ref, False, False)

    def trim(self):
        """Flat trim the drone."""
        self.at(at_ftrim)

    def set_speed(self, speed):
        """Set the drone's speed.

        Valid values are floats from [0..1]
        """
        self.speed = speed

    def at(self, cmd, *args, **kwargs):
        """Wrapper for the low level at commands.

        This method takes care that the sequence number is increased after each
        at command and the watchdog timer is started to make sure the drone
        receives a command at least every second.
        """
        self.lock.acquire()
        self.com_watchdog_timer.cancel()
        cmd(self.seq_nr, *args, **kwargs)
        self.seq_nr += 1
        self.com_watchdog_timer = threading.Timer(self.timer_t, self.commwdg)
        self.com_watchdog_timer.start()
        self.lock.release()

    def commwdg(self):
        """Communication watchdog signal.

        This needs to be send regular to keep the communication w/ the drone
        alive.
        """
        self.at(at_comwdg)

    def halt(self):
        """Shutdown the drone.

        This method does not land or halt the actual drone, but the
        communication with the drone. You should call it at the end of your
        application to close all sockets, pipes, processes and threads related
        with this object.
        """
        self.lock.acquire()
        self.com_watchdog_timer.cancel()
        self.com_pipe.send('die!')
        self.network_process.terminate()
        self.network_process.join()
        self.ipc_thread.stop()
        self.ipc_thread.join()
        self.lock.release()
        
    def move(self,lr, fb, vv, va):
        """Makes the drone move (translate/rotate).

 	   Parameters:
	   lr -- left-right tilt: float [-1..1] negative: left, positive: right
	   rb -- front-back tilt: float [-1..1] negative: forwards, positive:
        	backwards
	   vv -- vertical speed: float [-1..1] negative: go down, positive: rise
	   va -- angular speed: float [-1..1] negative: spin left, positive: spin 
        	right"""
        self.at(at_pcmd, True, lr, fb, vv, va)


###############################################################################
### Low level AT Commands
###############################################################################

def at_ref(seq, takeoff, emergency=False):
    """
    Basic behaviour of the drone: take-off/landing, emergency stop/reset)

    Parameters:
    seq -- sequence number
    takeoff -- True: Takeoff / False: Land
    emergency -- True: Turn of the engines
    """
    p = 0b10001010101000000000000000000
    if takeoff:
        p += 0b1000000000
    if emergency:
        p += 0b0100000000
    at("REF", seq, [p])

def at_pcmd(seq, progressive, lr, fb, vv, va):
    """
    Makes the drone move (translate/rotate).

    Parameters:
    seq -- sequence number
    progressive -- True: enable progressive commands, False: disable (i.e.
        enable hovering mode)
    lr -- left-right tilt: float [-1..1] negative: left, positive: right
    rb -- front-back tilt: float [-1..1] negative: forwards, positive:
        backwards
    vv -- vertical speed: float [-1..1] negative: go down, positive: rise
    va -- angular speed: float [-1..1] negative: spin left, positive: spin 
        right

    The above float values are a percentage of the maximum speed.
    """
    p = 1 if progressive else 0
    at("PCMD", seq, [p, float(lr), float(fb), float(vv), float(va)])

def at_ftrim(seq):
    """
    Tell the drone it's lying horizontally.

    Parameters:
    seq -- sequence number
    """
    at("FTRIM", seq, [])

def at_zap(seq, stream):
    """
    Selects which video stream to send on the video UDP port.

    Parameters:
    seq -- sequence number
    stream -- Integer: video stream to broadcast
    """
    # FIXME: improve parameters to select the modes directly
    at("ZAP", seq, [stream])

def at_config(seq, option, value):
    """Set configuration parameters of the drone."""
    at("CONFIG", seq, [str(option), str(value)])

def at_comwdg(seq):
    """
    Reset communication watchdog.
    """
    # FIXME: no sequence number
    at("COMWDG", seq, [])

def at_aflight(seq, flag):
    """
    Makes the drone fly autonomously.

    Parameters:
    seq -- sequence number
    flag -- Integer: 1: start flight, 0: stop flight
    """
    at("AFLIGHT", seq, [flag])

def at_pwm(seq, m1, m2, m3, m4):
    """
    Sends control values directly to the engines, overriding control loops.

    Parameters:
    seq -- sequence number
    m1 -- front left command
    m2 -- fright right command
    m3 -- back right command
    m4 -- back left command
    """
    # FIXME: what type do mx have?
    pass

def at_led(seq, anim, f, d):
    """
    Control the drones LED.

    Parameters:
    seq -- sequence number
    anim -- Integer: animation to play
    f -- ?: frequence in HZ of the animation
    d -- Integer: total duration in seconds of the animation
    """
    pass

def at_anim(seq, anim, d):
    """
    Makes the drone execute a predefined movement (animation).

    Parameters:
    seq -- sequence number
    anim -- Integer: animation to play
    d -- Integer: total duration in sections of the animation
    """
    at("ANIM", seq, [anim, d])

def at(command, seq, params):
    """
    Parameters:
    command -- the command
    seq -- the sequence number
    params -- a list of elements which can be either int, float or string
    """
    param_str = ''
    for p in params:
        if type(p) == int:
            param_str += ",%d" % p
        elif type(p) == float:
            param_str += ",%d" % f2i(p)
        elif type(p) == str:
            param_str += ',"'+p+'"'
    msg = "AT*%s=%i%s\r" % (command, seq, param_str)
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    sock.sendto(msg, ("192.168.1.1", ARDRONE_COMMAND_PORT))

def f2i(f):
    """Interpret IEEE-754 floating-point value as signed integer.

    Arguments:
    f -- floating point value
    """
    return struct.unpack('i', struct.pack('f', f))[0]

###############################################################################
### navdata
###############################################################################
def decode_navdata(packet):
    """Decode a navdata packet."""
    offset = 0
    _ =  struct.unpack_from("IIII", packet, offset)
    drone_state = dict()
    drone_state['fly_mask']             = _[1]       & 1 # FLY MASK : (0) ardrone is landed, (1) ardrone is flying
    drone_state['video_mask']           = _[1] >>  1 & 1 # VIDEO MASK : (0) video disable, (1) video enable
    drone_state['vision_mask']          = _[1] >>  2 & 1 # VISION MASK : (0) vision disable, (1) vision enable */
    drone_state['control_mask']         = _[1] >>  3 & 1 # CONTROL ALGO (0) euler angles control, (1) angular speed control */
    drone_state['altitude_mask']        = _[1] >>  4 & 1 # ALTITUDE CONTROL ALGO : (0) altitude control inactive (1) altitude control active */
    drone_state['user_feedback_start']  = _[1] >>  5 & 1 # USER feedback : Start button state */
    drone_state['command_mask']         = _[1] >>  6 & 1 # Control command ACK : (0) None, (1) one received */
    drone_state['fw_file_mask']         = _[1] >>  7 & 1 # Firmware file is good (1) */
    drone_state['fw_ver_mask']          = _[1] >>  8 & 1 # Firmware update is newer (1) */
    drone_state['fw_upd_mask']          = _[1] >>  9 & 1 # Firmware update is ongoing (1) */
    drone_state['navdata_demo_mask']    = _[1] >> 10 & 1 # Navdata demo : (0) All navdata, (1) only navdata demo */
    drone_state['navdata_bootstrap']    = _[1] >> 11 & 1 # Navdata bootstrap : (0) options sent in all or demo mode, (1) no navdata options sent */
    drone_state['motors_mask']          = _[1] >> 12 & 1 # Motor status : (0) Ok, (1) Motors problem */
    drone_state['com_lost_mask']        = _[1] >> 13 & 1 # Communication lost : (1) com problem, (0) Com is ok */
    drone_state['vbat_low']             = _[1] >> 15 & 1 # VBat low : (1) too low, (0) Ok */
    drone_state['user_el']              = _[1] >> 16 & 1 # User Emergency Landing : (1) User EL is ON, (0) User EL is OFF*/
    drone_state['timer_elapsed']        = _[1] >> 17 & 1 # Timer elapsed : (1) elapsed, (0) not elapsed */
    drone_state['angles_out_of_range']  = _[1] >> 19 & 1 # Angles : (0) Ok, (1) out of range */
    drone_state['ultrasound_mask']      = _[1] >> 21 & 1 # Ultrasonic sensor : (0) Ok, (1) deaf */
    drone_state['cutout_mask']          = _[1] >> 22 & 1 # Cutout system detection : (0) Not detected, (1) detected */
    drone_state['pic_version_mask']     = _[1] >> 23 & 1 # PIC Version number OK : (0) a bad version number, (1) version number is OK */
    drone_state['atcodec_thread_on']    = _[1] >> 24 & 1 # ATCodec thread ON : (0) thread OFF (1) thread ON */
    drone_state['navdata_thread_on']    = _[1] >> 25 & 1 # Navdata thread ON : (0) thread OFF (1) thread ON */
    drone_state['video_thread_on']      = _[1] >> 26 & 1 # Video thread ON : (0) thread OFF (1) thread ON */
    drone_state['acq_thread_on']        = _[1] >> 27 & 1 # Acquisition thread ON : (0) thread OFF (1) thread ON */
    drone_state['ctrl_watchdog_mask']   = _[1] >> 28 & 1 # CTRL watchdog : (1) delay in control execution (> 5ms), (0) control is well scheduled */
    drone_state['adc_watchdog_mask']    = _[1] >> 29 & 1 # ADC Watchdog : (1) delay in uart2 dsr (> 5ms), (0) uart2 is good */
    drone_state['com_watchdog_mask']    = _[1] >> 30 & 1 # Communication Watchdog : (1) com problem, (0) Com is ok */
    drone_state['emergency_mask']       = _[1] >> 31 & 1 # Emergency landing : (0) no emergency, (1) emergency */
    data = dict()
    data['drone_state'] = drone_state
    data['header'] = _[0]
    data['seq_nr'] = _[2]
    data['vision_flag'] = _[3]
    offset += struct.calcsize("IIII")
    while 1:
        try:
            id_nr, size =  struct.unpack_from("HH", packet, offset)
            offset += struct.calcsize("HH")
        except struct.error:
            break
        values = []
        for i in range(size-struct.calcsize("HH")):
            values.append(struct.unpack_from("c", packet, offset)[0])
            offset += struct.calcsize("c")
        # navdata_tag_t in navdata-common.h
        if id_nr == 0:
            values = struct.unpack_from("IIfffIfffI", "".join(values))
            values = dict(zip(['ctrl_state', 'battery', 'theta', 'phi', 'psi', 'altitude', 'vx', 'vy', 'vz', 'num_frames'], values))
            # convert the millidegrees into degrees and round to int, as they
            # are not so precise anyways
            for i in 'theta', 'phi', 'psi':
                values[i] = int(values[i] / 1000)
                #values[i] /= 1000
        data[id_nr] = values
    return data


if __name__ == "__main__":

    import termios
    import fcntl
    import os
    
    fd = sys.stdin.fileno()

    oldterm = termios.tcgetattr(fd)
    newattr = termios.tcgetattr(fd)
    newattr[3] = newattr[3] & ~termios.ICANON & ~termios.ECHO
    termios.tcsetattr(fd, termios.TCSANOW, newattr)

    oldflags = fcntl.fcntl(fd, fcntl.F_GETFL)
    fcntl.fcntl(fd, fcntl.F_SETFL, oldflags | os.O_NONBLOCK)

    drone = ARDrone()

    try:
        while 1:
            try:
                c = sys.stdin.read(1)
                c = c.lower()
                print "Got character", c
                if c == 'a':
                    drone.move_left()
                if c == 'd':
                    drone.move_right()
                if c == 'w':
                    drone.move_forward()
                if c == 's':
                    drone.move_backward()
                if c == ' ':
                    drone.land()
                if c == '\n':
                    drone.takeoff()
                if c == 'q':
                    drone.turn_left()
                if c == 'e':
                    drone.turn_right()
                if c == '1':
                    drone.move_up()
                if c == '2':
                    drone.hover()
                if c == '3':
                    drone.move_down()
                if c == 't':
                    drone.reset()
                if c == 'x':
                    drone.hover()
                if c == 'y':
                    drone.trim()
            except IOError:
                pass
    finally:
        termios.tcsetattr(fd, termios.TCSAFLUSH, oldterm)
        fcntl.fcntl(fd, fcntl.F_SETFL, oldflags)
        drone.halt()