quat_to_ypr.py

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#!/usr/bin/env python
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import roslib
roslib.load_manifest('starmac_tools') # change this to your package name
import rospy
from starmac_roslib.timers import Timer
# Message imports:
# Make sure corresponding packages are listed as dependencies in package manifest!
from std_msgs.msg import Bool, Float64
from nav_msgs.msg import Odometry
from starmac_msgs.msg import EulerAnglesStamped
import tf.transformations as tft
import numpy as np


class QuatToYPRNode(object):
    """
    Example python node including reading parameters, publishers and subscribers, and timer.
    """
    def __init__(self):
        # Remember that init_node hasn't been called yet so only do stuff here that
        # doesn't require node handles etc.
        pass

    def start(self):
        rospy.init_node('quat_to_ypr')
        self.init_params()
#        self.init_vars()
        self.init_publishers()
        self.init_subscribers()
        #self.init_timers()
        rospy.spin()
        
    def init_params(self):
        self.euler_seq = rospy.get_param("~euler_seq", 'rzyx')
        self.angles_in_degrees = rospy.get_param("~angles_in_degrees", True)
    
#    def init_vars(self):
#        self.some_variable = 42.0
#        self.latest_input = None

    def init_publishers(self):
        self.output_ypr_pub = rospy.Publisher('~ypr', EulerAnglesStamped)
        
    def init_subscribers(self):
        self.input_odom_sub = rospy.Subscriber(rospy.resolve_name('~odom'), Odometry, self.input_odom_callback)
      
#    def init_timers(self):
#        self.heartbeat_timer = Timer(rospy.Duration(1/10.0), self.heartbeat_timer_callback) # Call at 10 Hz
                                      
    def input_odom_callback(self, msg):
        euler_msg = EulerAnglesStamped()
        euler_msg.header.stamp = msg.header.stamp
        mppo = msg.pose.pose.orientation # shorthand
        quat = (mppo.x, mppo.y, mppo.z, mppo.w)
        ypr = tft.euler_from_quaternion(quat, self.euler_seq)
        euler_msg.angles.sequence = 'rzyx'
        euler_msg.angles.angles_in_degrees = True
        if self.angles_in_degrees:
            factor = np.degrees(1)
        else:
            factor = 1.0
        euler_msg.angles.ai = factor*ypr[0]
        euler_msg.angles.aj = factor*ypr[1]
        euler_msg.angles.ak = factor*ypr[2]
        self.output_ypr_pub.publish(euler_msg)
    
#    def heartbeat_timer_callback(self, event):
#        if event.last_real is not None:
#            dt = (event.current_real - event.last_real).to_sec()
#            rospy.loginfo('Heartbeat. dt = %f' % dt)
        
        
if __name__ == "__main__":
    self = QuatToYPRNode()
    self.start()