def __init__(self, default_port='/dev/ttyUSB0', default_update_rate=30.0):
"""
@param default_port: default tty port to use for establishing
connection to Turtlebot. This will be overriden by ~port ROS
param if available.
"""
self.default_port = default_port
self.default_update_rate = default_update_rate
self.robot = Create()#Turtlebot()
self.create_sensor_handler = None
self.sensor_state = TurtlebotSensorState()
self.req_cmd_vel = None
rospy.init_node('create')
self._init_params()
self._diagnostics = TurtlebotDiagnostics()
if self.has_gyro:
self._gyro = TurtlebotGyro()
else:
self._gyro = None
dynamic_reconfigure.server.Server(TurtleBotConfig, self.reconfigure)
class TurtlebotNode(object):
def __init__(self, default_port='/dev/ttyUSB0', default_update_rate=30.0):
"""
@param default_port: default tty port to use for establishing
connection to Turtlebot. This will be overriden by ~port ROS
param if available.
"""
self.default_port = default_port
self.default_update_rate = default_update_rate
self.robot = Create()#Turtlebot()
self.create_sensor_handler = None
self.sensor_state = TurtlebotSensorState()
self.req_cmd_vel = None
rospy.init_node('create')
self._init_params()
self._diagnostics = TurtlebotDiagnostics()
if self.has_gyro:
self._gyro = TurtlebotGyro()
else:
self._gyro = None
dynamic_reconfigure.server.Server(TurtleBotConfig, self.reconfigure)
def start(self):
log_once = True
while not rospy.is_shutdown():
try:
self.robot.start(self.port)
break
except serial.serialutil.SerialException as ex:
msg = "Failed to open port %s. Please make sure the Create cable is plugged into the computer. \n"%(self.port)
self._diagnostics.node_status(msg,"error")
if log_once:
log_once = False
rospy.logerr(msg)
else:
sys.stderr.write(msg)
time.sleep(3.0)
self.create_sensor_handler = TurtlebotSensorHandler(self.robot)
self.robot.safe = True
if rospy.get_param('~bonus', False):
bonus(self.robot)
self.robot.control()
# Write driver state to disk
with open(connected_file(), 'w') as f:
f.write("1")
self._init_pubsub()
def _init_params(self):
self.port = rospy.get_param('~port', self.default_port)
self.update_rate = rospy.get_param('~update_rate', self.default_update_rate)
self.drive_mode = rospy.get_param('~drive_mode', 'twist')
self.has_gyro = rospy.get_param('~has_gyro', False)
self.odom_angular_scale_correction = rospy.get_param('~odom_angular_scale_correction', 1.0)
self.odom_linear_scale_correction = rospy.get_param('~odom_linear_scale_correction', 1.0)
self.cmd_vel_timeout = rospy.Duration(rospy.get_param('~cmd_vel_timeout', 0.6))
self.stop_motors_on_bump = rospy.get_param('~stop_motors_on_bump', True)
self.min_abs_yaw_vel = rospy.get_param('~min_abs_yaw_vel', None)
rospy.loginfo("serial port: %s"%(self.port))
rospy.loginfo("update_rate: %s"%(self.update_rate))
rospy.loginfo("drive mode: %s"%(self.drive_mode))
rospy.loginfo("has gyro: %s"%(self.has_gyro))
def _init_pubsub(self):
self.joint_states_pub = rospy.Publisher('joint_states', JointState)
self.odom_pub = rospy.Publisher('odom', Odometry)
self.sensor_state_pub = rospy.Publisher('~sensor_state', TurtlebotSensorState)
self.operating_mode_srv = rospy.Service('~set_operation_mode', SetTurtlebotMode, self.set_operation_mode)
self.digital_output_srv = rospy.Service('~set_digital_outputs', SetDigitalOutputs, self.set_digital_outputs)
if self.drive_mode == 'twist':
self.cmd_vel_sub = rospy.Subscriber('cmd_vel', Twist, self.cmd_vel)
self.drive_cmd = self.robot.direct_drive
elif self.drive_mode == 'drive':
self.cmd_vel_sub = rospy.Subscriber('cmd_vel', Drive, self.cmd_vel)
self.drive_cmd = self.robot.drive
elif self.drive_mode == 'turtle':
self.cmd_vel_sub = rospy.Subscriber('cmd_vel', Turtle, self.cmd_vel)
self.drive_cmd = self.robot.direct_drive
else:
rospy.logerr("unknown drive mode :%s"%(self.drive_mode))
def reconfigure(self, config, level):
self.update_rate = config['update_rate']
self.drive_mode = config['drive_mode']
self.has_gyro = config['has_gyro']
if self.has_gyro:
self._gyro.gyro_scale_correction = config['gyro_scale_correction']
self.odom_angular_scale_correction = config['odom_angular_scale_correction']
self.odom_linear_scale_correction = config['odom_linear_scale_correction']
self.cmd_vel_timeout = rospy.Duration(config['cmd_vel_timeout'])
self.stop_motors_on_bump = config['stop_motors_on_bump']
self.min_abs_yaw_vel = config['min_abs_yaw_vel']
return config
def cmd_vel(self, msg):
# Clamp to min abs yaw velocity, to avoid trying to rotate at low
# speeds, which doesn't work well.
if self.min_abs_yaw_vel is not None and msg.angular.z != 0.0 and abs(msg.angular.z) < self.min_abs_yaw_vel:
msg.angular.z = self.min_abs_yaw_vel if msg.angular.z > 0.0 else -self.min_abs_yaw_vel
if self.drive_mode == 'twist':
# convert twist to direct_drive args
ts = msg.linear.x * 1000 # m -> mm
tw = msg.angular.z * (WHEEL_SEPARATION / 2)
# Prevent saturation at max wheel speed when a compound command is sent.
if ts > 0:
ts = min(ts, MAX_WHEEL_SPEED - abs(tw))
else:
ts = max(ts, -(MAX_WHEEL_SPEED - abs(tw)))
self.req_cmd_vel = int(ts - tw), int(ts + tw)
elif self.drive_mode == 'turtle':
# convert to direct_drive args
ts = msg.linear * 1000 # m -> mm
tw = msg.angular * (WHEEL_SEPARATION / 2)
self.req_cmd_vel = int(ts - tw), int(ts + tw)
elif self.drive_mode == 'drive':
# convert twist to drive args, m->mm (velocity, radius)
self.req_cmd_vel = msg.velocity * 1000, msg.radius * 1000
def set_operation_mode(self,req):
if req.mode == 1: #passive
self._robot_run_passive()
elif req.mode == 2: #safe
self._robot_run_safe()
elif req.mode == 3: #full
self._robot_run_full()
else:
rospy.logerr("Requested an invalid mode.")
return SetTurtlebotModeResponse(False)
return SetTurtlebotModeResponse(True)
def _robot_run_passive(self):
"""
Set robot into passive run mode
"""
rospy.logdebug("Setting turtlebot to passive mode.")
#setting all the digital outputs to 0
self._set_digital_outputs([0, 0, 0])
self.robot.passive()
def _robot_reboot(self):
"""
Perform a soft-reset of the Create
"""
msg ="Soft-rebooting turtlebot to passive mode."
rospy.logdebug(msg)
self._diagnostics.node_status(msg,"warn")
self._set_digital_outputs([0, 0, 0])
self.robot.soft_reset()
time.sleep(2.0)
def _robot_run_safe(self):
"""
Set robot into safe run mode
"""
rospy.logdebug("Setting turtlebot to safe mode.")
self._set_digital_outputs([1, 0, 0])
self.robot.safe = True
self.robot.control()
def _robot_run_full(self):
"""
Set robot into full run mode
"""
rospy.logdebug("Setting turtlebot to full mode.")
self.robot.safe = False
self.robot.control()
b1 = (self.sensor_state.user_digital_inputs & 2)/2
b2 = (self.sensor_state.user_digital_inputs & 4)/4
self._set_digital_outputs([1, b1, b2])
def _set_digital_outputs(self, outputs):
assert len(outputs) == 3, 'Expecting 3 output states.'
byte = 0
for output, state in enumerate(outputs):
byte += (2 ** output) * int(state)
self.robot.set_digital_outputs(byte)
self.sensor_state.user_digital_outputs = byte
def set_digital_outputs(self,req):
outputs = [req.digital_out_0,req.digital_out_1, req.digital_out_2]
self._set_digital_outputs(outputs)
return SetDigitalOutputsResponse(True)
def sense(self, sensor_state):
self.create_sensor_handler.get_all(sensor_state)
if self._gyro:
self._gyro.update_calibration(sensor_state)
def spin(self):
# state
pos2d = Pose2D()
s = self.sensor_state
odom = Odometry(header=rospy.Header(frame_id="odom"), child_frame_id='base_footprint')
js = JointState(name = ["left_wheel_joint", "right_wheel_joint", "front_castor_joint", "back_castor_joint"],
position=[0,0,0,0], velocity=[0,0,0,0], effort=[0,0,0,0])
r = rospy.Rate(self.update_rate)
last_cmd_vel = 0, 0
last_cmd_vel_time = rospy.get_rostime()
last_js_time = rospy.Time(0)
while not rospy.is_shutdown():
last_time = s.header.stamp
curr_time = rospy.get_rostime()
# SENSE/COMPUTE STATE
try:
self.sense(s)
transform = self.compute_odom(s, pos2d, last_time, odom)
# Future-date the joint states so that we don't have
# to publish as frequently.
js.header.stamp = curr_time + rospy.Duration(1)
except select.error:
# packet read can get interrupted, restart loop to
# check for exit conditions
continue
# Reboot Create if we detect that charging is necessary.
if s.charging_sources_available > 0 and \
s.oi_mode == 1 and \
s.charging_state in [0, 5] and \
s.charge < 0.93*s.capacity:
rospy.loginfo("going into soft-reboot and exiting driver")
self._robot_reboot()
rospy.loginfo("exiting driver")
break
# Reboot Create if we detect that battery is at critical level switch to passive mode.
if s.charging_sources_available > 0 and \
s.oi_mode == 3 and \
s.charging_state in [0, 5] and \
s.charge < 0.15*s.capacity:
rospy.loginfo("going into soft-reboot and exiting driver")
self._robot_reboot()
rospy.loginfo("exiting driver")
break
# PUBLISH STATE
self.sensor_state_pub.publish(s)
self.odom_pub.publish(odom)
# 1hz, future-dated joint state
if curr_time > last_js_time + rospy.Duration(1):
self.joint_states_pub.publish(js)
last_js_time = curr_time
self._diagnostics.publish(s, self._gyro)
if self._gyro:
self._gyro.publish(s, last_time)
# ACT
if self.req_cmd_vel is not None:
# check for velocity command and set the robot into full mode if not plugged in
if s.oi_mode < 3 and s.charging_sources_available != 1:
self._robot_run_full()
# check for bumper contact and limit drive command
req_cmd_vel = self.check_bumpers(s, self.req_cmd_vel)
# Set to None so we know it's a new command
self.req_cmd_vel = None
# reset time for timeout
last_cmd_vel_time = last_time
else:
#zero commands on timeout
if last_time - last_cmd_vel_time > self.cmd_vel_timeout:
last_cmd_vel = 0,0
# double check bumpers
req_cmd_vel = self.check_bumpers(s, last_cmd_vel)
# send command
self.drive_cmd(*req_cmd_vel)
# record command
last_cmd_vel = req_cmd_vel
r.sleep()
def check_bumpers(self, s, cmd_vel):
# Safety: disallow forward motion if bumpers or wheeldrops
# are activated.
# TODO: check bumps_wheeldrops flags more thoroughly, and disable
# all motion (not just forward motion) when wheeldrops are activated
forward = (cmd_vel[0] + cmd_vel[1]) > 0
if self.stop_motors_on_bump and s.bumps_wheeldrops > 0 and forward:
return (0,0)
else:
return cmd_vel
def compute_odom(self, sensor_state, pos2d, last_time, odom):
"""
Compute current odometry. Updates odom instance and returns tf
transform. compute_odom() does not set frame ids or covariances in
Odometry instance. It will only set stamp, pose, and twist.
@param sensor_state: Current sensor reading
@type sensor_state: TurtlebotSensorState
@param pos2d: Current position
@type pos2d: geometry_msgs.msg.Pose2D
@param last_time: time of last sensor reading
@type last_time: rospy.Time
@param odom: Odometry instance to update.
@type odom: nav_msgs.msg.Odometry
@return: transform
@rtype: ( (float, float, float), (float, float, float, float) )
"""
# based on otl_roomba by OTL <*****@*****.**>
current_time = sensor_state.header.stamp
dt = (current_time - last_time).to_sec()
# this is really delta_distance, delta_angle
d = sensor_state.distance * self.odom_linear_scale_correction #correction factor from calibration
angle = sensor_state.angle * self.odom_angular_scale_correction #correction factor from calibration
x = cos(angle) * d
y = -sin(angle) * d
last_angle = pos2d.theta
pos2d.x += cos(last_angle)*x - sin(last_angle)*y
pos2d.y += sin(last_angle)*x + cos(last_angle)*y
pos2d.theta += angle
# Turtlebot quaternion from yaw. simplified version of tf.transformations.quaternion_about_axis
odom_quat = (0., 0., sin(pos2d.theta/2.), cos(pos2d.theta/2.))
# construct the transform
transform = (pos2d.x, pos2d.y, 0.), odom_quat
# update the odometry state
odom.header.stamp = current_time
odom.pose.pose = Pose(Point(pos2d.x, pos2d.y, 0.), Quaternion(*odom_quat))
odom.twist.twist = Twist(Vector3(d/dt, 0, 0), Vector3(0, 0, angle/dt))
if sensor_state.requested_right_velocity == 0 and \
sensor_state.requested_left_velocity == 0 and \
sensor_state.distance == 0:
odom.pose.covariance = ODOM_POSE_COVARIANCE2
odom.twist.covariance = ODOM_TWIST_COVARIANCE2
else:
odom.pose.covariance = ODOM_POSE_COVARIANCE
odom.twist.covariance = ODOM_TWIST_COVARIANCE
# return the transform
return transform
