scripts/move_base.py

   1 #!/usr/bin/env python
   2 # -*- coding: iso-8859-15 -*-
   3
   4 import rospy
   5 import tf
   6 import struct
   7 from i2c import *
   8 from math import *
   9 from geometry_msgs.msg import Twist
  10 from nav_msgs.msg import Odometry
  11 from diagnostic_msgs.msg import DiagnosticArray, DiagnosticStatus, KeyValue
  12
  13 WHEEL_DIST = 0.248
  14
  15 class MoveBase:
  16         def __init__(self):
  17                 rospy.init_node('wild_thumper_move_base')
  18                 rospy.Subscriber("cmd_vel", Twist, self.cmdVelReceived)
  19                 self.tf_broadcaster = tf.broadcaster.TransformBroadcaster()
  20                 self.pub_odom = rospy.Publisher("odom", Odometry, queue_size=16)
  21                 self.pub_diag = rospy.Publisher("diagnostics", DiagnosticArray, queue_size=16)
  22                 self.set_speed(0, 0)
  23                 rospy.loginfo("Init done")
  24                 i2c_write_reg(0x50, 0x90, struct.pack("BB", 1, 1)) # switch direction
  25                 self.run()
  26
  27         def run(self):
  28                 rate = rospy.Rate(20.0)
  29                 reset_val = self.get_reset()
  30                 rospy.loginfo("Reset Status: 0x%x" % reset_val)
  31                 while not rospy.is_shutdown():
  32                         #print struct.unpack(">B", i2c_read_reg(0x50, 0xA2, 1))[0] # count test
  33                         self.get_tle_err()
  34                         self.get_odom()
  35                         self.get_voltage()
  36                         #self.get_dist_forward()
  37                         #self.get_dist_backward()
  38                         #self.get_dist_left()
  39                         #self.get_dist_right()
  40                         rate.sleep()
  41
  42         def get_reset(self):
  43                 reset = struct.unpack(">B", i2c_read_reg(0x50, 0xA0, 1))[0]
  44
  45                 msg = DiagnosticArray()
  46                 msg.header.stamp = rospy.Time.now()
  47                 stat = DiagnosticStatus()
  48                 stat.name = "Reset reason"
  49                 stat.level = DiagnosticStatus.ERROR if reset & 0x0c else DiagnosticStatus.OK
  50                 stat.message = "0x%02x" % reset
  51
  52                 stat.values.append(KeyValue("Watchdog Reset Flag", str(bool(reset & (1 << 3)))))
  53                 stat.values.append(KeyValue("Brown-out Reset Flag", str(bool(reset & (1 << 2)))))
  54                 stat.values.append(KeyValue("External Reset Flag", str(bool(reset & (1 << 1)))))
  55                 stat.values.append(KeyValue("Power-on Reset Flag", str(bool(reset & (1 << 0)))))
  56
  57                 msg.status.append(stat)
  58                 self.pub_diag.publish(msg)
  59                 return reset
  60
  61
  62         def get_tle_err(self):
  63                 err = struct.unpack(">B", i2c_read_reg(0x50, 0xA1, 1))[0]
  64
  65                 msg = DiagnosticArray()
  66                 msg.header.stamp = rospy.Time.now()
  67                 stat = DiagnosticStatus()
  68                 stat.name = "Motor: Error Status"
  69                 stat.level = DiagnosticStatus.ERROR if err else DiagnosticStatus.OK
  70                 stat.message = "0x%02x" % err
  71
  72                 stat.values.append(KeyValue("Motor 1", str(bool(err & (1 << 0)))))
  73                 stat.values.append(KeyValue("Motor 2", str(bool(err & (1 << 1)))))
  74                 stat.values.append(KeyValue("Motor 3", str(bool(err & (1 << 2)))))
  75                 stat.values.append(KeyValue("Motor 4", str(bool(err & (1 << 3)))))
  76
  77                 msg.status.append(stat)
  78                 self.pub_diag.publish(msg)
  79
  80         def get_voltage(self):
  81                 volt = struct.unpack(">h", i2c_read_reg(0x52, 0x09, 2))[0]/100.0
  82
  83                 msg = DiagnosticArray()
  84                 msg.header.stamp = rospy.Time.now()
  85                 stat = DiagnosticStatus()
  86                 stat.name = "Voltage"
  87                 stat.level = DiagnosticStatus.ERROR if volt < 6 else DiagnosticStatus.OK
  88                 stat.message = "%.2fV" % volt
  89
  90                 msg.status.append(stat)
  91                 self.pub_diag.publish(msg)
  92
  93
  94         def get_odom(self):
  95                 posx, posy, angle = struct.unpack(">fff", i2c_read_reg(0x50, 0x40, 12))
  96                 speed_trans, speed_rot = struct.unpack(">ff", i2c_read_reg(0x50, 0x38, 8))
  97                 current_time = rospy.Time.now()
  98
  99                 # since all odometry is 6DOF we'll need a quaternion created from yaw
 100                 odom_quat = tf.transformations.quaternion_from_euler(0, 0, angle)
 101
 102                 # first, we'll publish the transform over tf
 103                 self.tf_broadcaster.sendTransform((posx, posy, 0.0), odom_quat, current_time, "base_link", "odom")
 104
 105                 # next, we'll publish the odometry message over ROS
 106                 odom = Odometry()
 107                 odom.header.stamp = current_time
 108                 odom.header.frame_id = "/odom"
 109
 110                 # set the position
 111                 odom.pose.pose.position.x = posx
 112                 odom.pose.pose.position.y = posy
 113                 odom.pose.pose.position.z = 0.0
 114                 odom.pose.pose.orientation.x = odom_quat[0]
 115                 odom.pose.pose.orientation.y = odom_quat[1]
 116                 odom.pose.pose.orientation.z = odom_quat[2]
 117                 odom.pose.pose.orientation.w = odom_quat[3]
 118
 119                 # set the velocity
 120                 odom.child_frame_id = "base_link"
 121                 odom.twist.twist.linear.x = speed_trans
 122                 odom.twist.twist.linear.y = 0.0
 123                 odom.twist.twist.angular.z = speed_rot
 124
 125                 # publish the message
 126                 self.pub_odom.publish(odom)
 127
 128
 129         def set_speed(self, trans, rot):
 130                 i2c_write_reg(0x50, 0x50, struct.pack(">ff", trans, rot))
 131
 132         def cmdVelReceived(self, msg):
 133                 trans = msg.linear.x
 134                 rot = msg.angular.z # rad/s
 135                 self.set_speed(trans, rot)
 136
 137         # http://rn-wissen.de/wiki/index.php/Sensorarten#Sharp_GP2D12
 138         def get_dist_ir(self, num):
 139                 dev = i2c(0x52)
 140                 s = struct.pack("B", num)
 141                 dev.write(s)
 142                 dev.close()
 143
 144                 sleep(2e-6)
 145
 146                 dev = i2c(0x52)
 147                 s = dev.read(2)
 148                 dev.close()
 149
 150                 val = struct.unpack(">H", s)[0]
 151                 return 15221/(val - -276.42)/100;
 152
 153         def get_dist_srf(self, num):
 154                 dev = i2c(0x52)
 155                 s = struct.pack("B", num)
 156                 dev.write(s)
 157                 dev.close()
 158
 159                 sleep(50e-3)
 160
 161                 dev = i2c(0x52)
 162                 s = dev.read(2)
 163                 dev.close()
 164
 165                 return struct.unpack(">H", s)[0]/1000.0
 166
 167         def get_dist_left(self):
 168                 dist = self.get_dist_ir(0x1)
 169
 170         def get_dist_right(self):
 171                  dist = self.get_dist_ir(0x3)
 172
 173         def get_dist_forward(self):
 174                 dist = self.get_dist_srf(0x5)
 175
 176         def get_dist_backward(self):
 177                 dist = self.get_dist_srf(0x7)
 178
 179
 180 if __name__ == "__main__":
 181         MoveBase()