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_AckermannDrive.py

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"""autogenerated by genmsg_py from AckermannDrive.msg. Do not edit."""
import roslib.message
import struct


class AckermannDrive(roslib.message.Message):
  _md5sum = "3512e91b48d69674a0e86fadf1ea8231"
  _type = "ackermann_msgs/AckermannDrive"
  _has_header = False #flag to mark the presence of a Header object
  _full_text = """## Driving command for a car-like vehicle using Ackermann steering.
#  $Id: AckermannDrive.msg 1966 2012-02-11 17:52:11Z jack.oquin $

# Assumes Ackermann front-wheel steering. The left and right front
# wheels are generally at different angles. To simplify, the commanded
# angle corresponds to the yaw of a virtual wheel located at the
# center of the front axle, like on a tricycle.  Positive yaw is to
# the left. (This is *not* the angle of the steering wheel inside the
# passenger compartment.)
#
# Zero steering angle velocity means change the steering angle as
# quickly as possible. Positive velocity indicates a desired absolute
# rate of change either left or right. The controller tries not to
# exceed this limit in either direction, but sometimes it might.
#
float32 steering_angle          # desired virtual angle (radians)
float32 steering_angle_velocity # desired rate of change (radians/s)

# Drive at requested speed, acceleration and jerk (the 1st, 2nd and
# 3rd derivatives of position). All are measured at the vehicle's
# center of rotation, typically the center of the rear axle. The
# controller tries not to exceed these limits in either direction, but
# sometimes it might.
#
# Speed is the desired scalar magnitude of the velocity vector.
# Direction is forward unless the sign is negative, indicating reverse.
#
# Zero acceleration means change speed as quickly as
# possible. Positive acceleration indicates a desired absolute
# magnitude; that includes deceleration.
#
# Zero jerk means change acceleration as quickly as possible. Positive
# jerk indicates a desired absolute rate of acceleration change in
# either direction (increasing or decreasing).
#
float32 speed                   # desired forward speed (m/s)
float32 acceleration            # desired acceleration (m/s^2)
float32 jerk                    # desired jerk (m/s^3)

"""
  __slots__ = ['steering_angle','steering_angle_velocity','speed','acceleration','jerk']
  _slot_types = ['float32','float32','float32','float32','float32']

  def __init__(self, *args, **kwds):
    """
    Constructor. Any message fields that are implicitly/explicitly
    set to None will be assigned a default value. The recommend
    use is keyword arguments as this is more robust to future message
    changes.  You cannot mix in-order arguments and keyword arguments.
    
    The available fields are:
       steering_angle,steering_angle_velocity,speed,acceleration,jerk
    
    @param args: complete set of field values, in .msg order
    @param kwds: use keyword arguments corresponding to message field names
    to set specific fields. 
    """
    if args or kwds:
      super(AckermannDrive, self).__init__(*args, **kwds)
      #message fields cannot be None, assign default values for those that are
      if self.steering_angle is None:
        self.steering_angle = 0.
      if self.steering_angle_velocity is None:
        self.steering_angle_velocity = 0.
      if self.speed is None:
        self.speed = 0.
      if self.acceleration is None:
        self.acceleration = 0.
      if self.jerk is None:
        self.jerk = 0.
    else:
      self.steering_angle = 0.
      self.steering_angle_velocity = 0.
      self.speed = 0.
      self.acceleration = 0.
      self.jerk = 0.

  def _get_types(self):
    """
    internal API method
    """
    return self._slot_types

  def serialize(self, buff):
    """
    serialize message into buffer
    @param buff: buffer
    @type  buff: StringIO
    """
    try:
      _x = self
      buff.write(_struct_5f.pack(_x.steering_angle, _x.steering_angle_velocity, _x.speed, _x.acceleration, _x.jerk))
    except struct.error as se: self._check_types(se)
    except TypeError as te: self._check_types(te)

  def deserialize(self, str):
    """
    unpack serialized message in str into this message instance
    @param str: byte array of serialized message
    @type  str: str
    """
    try:
      end = 0
      _x = self
      start = end
      end += 20
      (_x.steering_angle, _x.steering_angle_velocity, _x.speed, _x.acceleration, _x.jerk,) = _struct_5f.unpack(str[start:end])
      return self
    except struct.error as e:
      raise roslib.message.DeserializationError(e) #most likely buffer underfill


  def serialize_numpy(self, buff, numpy):
    """
    serialize message with numpy array types into buffer
    @param buff: buffer
    @type  buff: StringIO
    @param numpy: numpy python module
    @type  numpy module
    """
    try:
      _x = self
      buff.write(_struct_5f.pack(_x.steering_angle, _x.steering_angle_velocity, _x.speed, _x.acceleration, _x.jerk))
    except struct.error as se: self._check_types(se)
    except TypeError as te: self._check_types(te)

  def deserialize_numpy(self, str, numpy):
    """
    unpack serialized message in str into this message instance using numpy for array types
    @param str: byte array of serialized message
    @type  str: str
    @param numpy: numpy python module
    @type  numpy: module
    """
    try:
      end = 0
      _x = self
      start = end
      end += 20
      (_x.steering_angle, _x.steering_angle_velocity, _x.speed, _x.acceleration, _x.jerk,) = _struct_5f.unpack(str[start:end])
      return self
    except struct.error as e:
      raise roslib.message.DeserializationError(e) #most likely buffer underfill

_struct_I = roslib.message.struct_I
_struct_5f = struct.Struct("<5f")

---

ackermann_msgs
Author(s): Jack O'Quin
autogenerated on Fri Mar 1 14:00:17 2013