test_publisher_twist_sine.py

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#!/usr/bin/env python
#
# Copyright 2017 Fraunhofer Institute for Manufacturing Engineering and Automation (IPA)
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.


import rospy
import math
from geometry_msgs.msg import Twist


def velPub():
  rospy.init_node("test_publisher_twist", anonymous=True)

  pub_vel = rospy.Publisher("command", Twist, queue_size=1)
  rospy.sleep(1.0)

  freq = 10.0
  r = rospy.Rate(freq)

  a = 0.5#-1.0
  b = 0.1 * (2.0*math.pi/freq)
  c = -math.pi/2.0
  d = a
  i = 0.0
  
  vel_msg = Twist()
  time = rospy.Time.now()

  while not rospy.is_shutdown():
    vel = a*math.sin(b*i+c) + d
    #print("vel: ", vel)
    vel_msg.angular.z = vel
    pub_vel.publish(vel_msg)
    i += 1.0
    r.sleep()

if __name__ == '__main__':
  try:
      velPub()
  except rospy.ROSInterruptException: pass