scripts/robo_explorer.py

   1 #!/usr/bin/env python
   2 import roslib; roslib.load_manifest('roboint')
   3 import rospy
   4 import tf
   5 from math import sin, cos
   6 from geometry_msgs.msg import Twist, TransformStamped, Point32
   7 from sensor_msgs.msg import PointCloud
   8 from nav_msgs.msg import Odometry
   9 from roboint.msg import Motor
  10 from roboint.msg import Inputs
  11
  12
  13 class RoboExplorer:
  14         def __init__(self):
  15                 rospy.init_node('robo_explorer')
  16
  17                 rospy.Subscriber("cmd_vel", Twist, self.cmdVelReceived)
  18                 rospy.Subscriber("ft/get_inputs", Inputs, self.inputsReceived)
  19
  20                 self.pub_motor = rospy.Publisher("ft/set_motor", Motor)
  21                 self.pub_cloud = rospy.Publisher("point_cloud", PointCloud)
  22                 self.pub_odom = rospy.Publisher("odom", Odometry)
  23
  24                 self.speed = (0, 0)
  25                 self.x = 0
  26                 self.y = 0
  27                 self.th = 0
  28                 self.last_in = [0, 0]
  29                 self.odom_broadcaster = tf.TransformBroadcaster()
  30                 self.last_time = rospy.Time.now()
  31
  32                 rospy.spin()
  33
  34         def inputsReceived(self, msg):
  35                 current_time = rospy.Time.now()
  36
  37                 cloud = PointCloud()
  38                 cloud.header.stamp = current_time
  39                 cloud.header.frame_id = "sensor_frame"
  40                 cloud.points.append(Point32(msg.d1/10.0, 0, 0))
  41                 self.pub_cloud.publish(cloud)
  42
  43                 dt = (current_time - self.last_time).to_sec();
  44                 in_now = msg.input[1:3]
  45                 in_diff = [abs(a - b) for a, b in zip(in_now, self.last_in)] # get changed inputs
  46                 if self.speed[0] < 0:
  47                         in_diff[0] = -in_diff[0]
  48                 if self.speed[1] < 0:
  49                         in_diff[1] = -in_diff[1]
  50
  51                 self.diff_to_angle = 0.1 # TODO
  52                 diff_si = in_diff # TODO
  53
  54                 delta_th = (diff_si[0] - diff_si[1]) * self.diff_to_angle
  55                 self.th += delta_th
  56
  57                 movement = (diff_si[0] + diff_si[1])/2.0
  58                 delta_x = cos(self.th)*movement
  59                 delta_y = sin(self.th)*movement
  60                 self.x += delta_x
  61                 self.y += delta_y
  62
  63                 # speeds
  64                 vx = delta_x / dt
  65                 vy = delta_y / dt
  66                 vth = delta_th / dt
  67
  68                 # first, we'll publish the transform over tf
  69                 odom_trans = TransformStamped()
  70                 odom_trans.header.stamp = current_time
  71                 odom_trans.header.frame_id = "odom"
  72                 odom_trans.child_frame_id = "base_link"
  73                 odom_trans.transform.translation.x = self.x
  74                 odom_trans.transform.translation.y = self.y
  75                 odom_trans.transform.translation.z = 0.0
  76                 odom_trans.transform.rotation = self.th
  77
  78                 ## send the transform
  79                 #self.odom_broadcaster.sendTransform(odom_trans);
  80
  81                 # next, we'll publish the odometry message over ROS
  82                 odom = Odometry()
  83                 odom.header.stamp = current_time
  84                 odom.header.frame_id = "odom"
  85
  86                 # set the position
  87                 odom.pose.pose.position.x = self.x
  88                 odom.pose.pose.position.y = self.y
  89                 odom.pose.pose.position.z = 0.0
  90                 odom.pose.pose.orientation = self.th
  91
  92                 # set the velocity
  93                 odom.child_frame_id = "base_link";
  94                 odom.twist.twist.linear.x = vx
  95                 odom.twist.twist.linear.y = vy
  96                 odom.twist.twist.angular.z = vth
  97
  98                 # publish the message
  99                 self.pub_odom.publish(odom)
 100
 101                 self.last_time = current_time
 102                 self.last_in = in_now
 103
 104
 105         def cmdVelReceived(self, msg):
 106                 trans = msg.linear.x
 107                 rot = msg.angular.z
 108
 109                 # speed steps = 7
 110                 # max trans = 0.1m/s
 111                 # max rot = 0.29rad/s
 112
 113                 speed_l = int(trans*7/0.1 - rot*7/0.29)
 114                 speed_r = int(trans*7/0.1 + rot*7/0.29)
 115                 if speed_l < -7: speed_l = -7
 116                 elif speed_l > 7: speed_l = 7
 117                 if speed_r < -7: speed_r = -7
 118                 elif speed_r > 7: speed_r = 7
 119
 120                 outmsg = Motor()
 121                 outmsg.num = 1
 122                 outmsg.speed = speed_l
 123                 self.pub_motor.publish(outmsg)
 124
 125                 outmsg = Motor()
 126                 outmsg.num = 2
 127                 outmsg.speed = speed_r
 128                 self.pub_motor.publish(outmsg)
 129
 130                 self.speed = (speed_l, speed_r)
 131
 132 if __name__ == '__main__':
 133         RoboExplorer()