caster_cmder.py

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#! /usr/bin/env python
#
# Copyright (c) 2009, Willow Garage, Inc.
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##\author Kevin Watts

PKG = 'life_test'
import roslib
roslib.load_manifest(PKG)
import time
import random
import rospy
from std_msgs.msg import Float64

ROTATION_JOINT = 'fl_caster_rotation_joint'
TOPIC_PREFIX = 'caster_fl'
SPEED = 0.1 #Changed from 100, 11/20
STEER_VEL = 6.0 #Changed from 100, 11/20

class CasterCmd:
    def __init__(self):
        self.steer = STEER_VEL
        self.drive = SPEED

        self._count = 0
 
    ##\brief 8% duty cycle on turn, regular sequence
    def update(self):
        if self._count == 0:
            # Slower steering velocity to make caster process
            self.steer = -0.8 * STEER_VEL
            self.drive = 0
        elif self._count == 1:
            self.steer = STEER_VEL
            self.drive = 0
        else:
            self.steer = 0
            if self._count % 2 == 0:
                self.drive = SPEED
            else:
                self.drive = -1 * SPEED

        self._count += 1
        if self._count >= 25:
            self._count = 0
            
                    
def main():
    rospy.init_node('caster_cmder')
    cmder = CasterCmd()
    pub_steer = rospy.Publisher("%s/steer" % TOPIC_PREFIX, Float64)
    pub_drive = rospy.Publisher("%s/drive" % TOPIC_PREFIX, Float64)
    pub_steer.publish(Float64(0.0))
    pub_drive.publish(Float64(0.0))

    my_rate = rospy.Rate(float(rospy.get_param('cycle_rate', 1.0)))
    while not rospy.is_shutdown():
        pub_steer.publish(Float64(cmder.steer))
        pub_drive.publish(Float64(cmder.drive))
        
        cmder.update()
        my_rate.sleep()
        

if __name__ == '__main__':
    main()