scripts/wt_node.py

   1 #!/usr/bin/env python
   2 # -*- coding: iso-8859-15 -*-
   3
   4 import rospy
   5 import tf
   6 import struct
   7 import prctl
   8 from i2c import *
   9 from math import *
  10 from geometry_msgs.msg import Twist
  11 from nav_msgs.msg import Odometry
  12 from diagnostic_msgs.msg import DiagnosticArray, DiagnosticStatus, KeyValue
  13 from sensor_msgs.msg import Imu, Range
  14
  15 WHEEL_DIST = 0.248
  16
  17 class MoveBase:
  18         def __init__(self):
  19                 rospy.init_node('wild_thumper')
  20                 prctl.set_name("wild_thumper")
  21                 rospy.Subscriber("cmd_vel_out", Twist, self.cmdVelReceived)
  22                 rospy.Subscriber("imu", Imu, self.imuReceived)
  23                 enable_odom_tf = rospy.get_param("~enable_odom_tf", True)
  24                 if enable_odom_tf:
  25                         self.tf_broadcaster = tf.broadcaster.TransformBroadcaster()
  26                 else:
  27                         self.tf_broadcaster = None
  28                 self.pub_odom = rospy.Publisher("odom", Odometry, queue_size=16)
  29                 self.pub_diag = rospy.Publisher("diagnostics", DiagnosticArray, queue_size=16)
  30                 self.pub_range_fwd = rospy.Publisher("range_forward", Range, queue_size=16)
  31                 self.pub_range_bwd = rospy.Publisher("range_backward", Range, queue_size=16)
  32                 self.pub_range_left = rospy.Publisher("range_left", Range, queue_size=16)
  33                 self.pub_range_right = rospy.Publisher("range_right", Range, queue_size=16)
  34                 self.set_speed(0, 0)
  35                 rospy.loginfo("Init done")
  36                 i2c_write_reg(0x50, 0x90, struct.pack("BB", 1, 1)) # switch direction
  37                 self.handicap_last = (-1, -1)
  38                 self.run()
  39
  40         def run(self):
  41                 rate = rospy.Rate(20.0)
  42                 reset_val = self.get_reset()
  43                 rospy.loginfo("Reset Status: 0x%x" % reset_val)
  44                 i = 0
  45                 while not rospy.is_shutdown():
  46                         #print struct.unpack(">B", i2c_read_reg(0x50, 0xA2, 1))[0] # count test
  47                         self.get_tle_err()
  48                         self.get_odom()
  49                         self.get_voltage()
  50                         if i % 2:
  51                                 self.get_dist_forward()
  52                                 self.get_dist_left()
  53                         else:
  54                                 self.get_dist_backward()
  55                                 self.get_dist_right()
  56                         i+=1
  57                         rate.sleep()
  58
  59         def set_motor_handicap(self, front, aft): # percent
  60                 if self.handicap_last != (front, aft):
  61                         i2c_write_reg(0x50, 0x94, struct.pack(">bb", front, aft))
  62                         self.handicap_last = (front, aft)
  63
  64         def imuReceived(self, msg):
  65                 (roll, pitch, yaw) = tf.transformations.euler_from_quaternion(msg.orientation.__getstate__())
  66                 if pitch > 30*pi/180:
  67                         val = (100.0/65)*abs(pitch)*180/pi
  68                         self.set_motor_handicap(int(val), 0)
  69                 elif pitch < -30*pi/180:
  70                         val = (100.0/65)*abs(pitch)*180/pi
  71                         self.set_motor_handicap(0, int(val))
  72                 else:
  73                         self.set_motor_handicap(0, 0)
  74
  75         def get_reset(self):
  76                 reset = struct.unpack(">B", i2c_read_reg(0x50, 0xA0, 1))[0]
  77
  78                 msg = DiagnosticArray()
  79                 msg.header.stamp = rospy.Time.now()
  80                 stat = DiagnosticStatus()
  81                 stat.name = "Reset reason"
  82                 stat.level = DiagnosticStatus.ERROR if reset & 0x0c else DiagnosticStatus.OK
  83                 stat.message = "0x%02x" % reset
  84
  85                 stat.values.append(KeyValue("Watchdog Reset Flag", str(bool(reset & (1 << 3)))))
  86                 stat.values.append(KeyValue("Brown-out Reset Flag", str(bool(reset & (1 << 2)))))
  87                 stat.values.append(KeyValue("External Reset Flag", str(bool(reset & (1 << 1)))))
  88                 stat.values.append(KeyValue("Power-on Reset Flag", str(bool(reset & (1 << 0)))))
  89
  90                 msg.status.append(stat)
  91                 self.pub_diag.publish(msg)
  92                 return reset
  93
  94
  95         def get_tle_err(self):
  96                 err = struct.unpack(">B", i2c_read_reg(0x50, 0xA1, 1))[0]
  97
  98                 msg = DiagnosticArray()
  99                 msg.header.stamp = rospy.Time.now()
 100                 stat = DiagnosticStatus()
 101                 stat.name = "Motor: Error Status"
 102                 stat.level = DiagnosticStatus.ERROR if err else DiagnosticStatus.OK
 103                 stat.message = "0x%02x" % err
 104
 105                 stat.values.append(KeyValue("aft left", str(bool(err & (1 << 0)))))
 106                 stat.values.append(KeyValue("front left", str(bool(err & (1 << 1)))))
 107                 stat.values.append(KeyValue("front right", str(bool(err & (1 << 2)))))
 108                 stat.values.append(KeyValue("aft right", str(bool(err & (1 << 3)))))
 109
 110                 msg.status.append(stat)
 111                 self.pub_diag.publish(msg)
 112
 113         def get_voltage(self):
 114                 volt = struct.unpack(">h", i2c_read_reg(0x52, 0x09, 2))[0]/100.0
 115
 116                 msg = DiagnosticArray()
 117                 msg.header.stamp = rospy.Time.now()
 118                 stat = DiagnosticStatus()
 119                 stat.name = "Voltage"
 120                 stat.level = DiagnosticStatus.ERROR if volt < 7 else DiagnosticStatus.OK
 121                 stat.message = "%.2fV" % volt
 122
 123                 msg.status.append(stat)
 124                 self.pub_diag.publish(msg)
 125
 126
 127         def get_odom(self):
 128                 posx, posy, angle = struct.unpack(">fff", i2c_read_reg(0x50, 0x40, 12))
 129                 speed_trans, speed_rot = struct.unpack(">ff", i2c_read_reg(0x50, 0x38, 8))
 130                 current_time = rospy.Time.now()
 131
 132                 # since all odometry is 6DOF we'll need a quaternion created from yaw
 133                 odom_quat = tf.transformations.quaternion_from_euler(0, 0, angle)
 134
 135                 # first, we'll publish the transform over tf
 136                 if self.tf_broadcaster is not None:
 137                         self.tf_broadcaster.sendTransform((posx, posy, 0.0), odom_quat, current_time, "base_footprint", "odom")
 138
 139                 # next, we'll publish the odometry message over ROS
 140                 odom = Odometry()
 141                 odom.header.stamp = current_time
 142                 odom.header.frame_id = "odom"
 143
 144                 # set the position
 145                 odom.pose.pose.position.x = posx
 146                 odom.pose.pose.position.y = posy
 147                 odom.pose.pose.position.z = 0.0
 148                 odom.pose.pose.orientation.x = odom_quat[0]
 149                 odom.pose.pose.orientation.y = odom_quat[1]
 150                 odom.pose.pose.orientation.z = odom_quat[2]
 151                 odom.pose.pose.orientation.w = odom_quat[3]
 152                 odom.pose.covariance[0] = 1e-3 # x
 153                 odom.pose.covariance[7] = 1e-3 # y
 154                 odom.pose.covariance[14] = 1e6 # z
 155                 odom.pose.covariance[21] = 1e6 # rotation about X axis
 156                 odom.pose.covariance[28] = 1e6 # rotation about Y axis
 157                 odom.pose.covariance[35] = 0.03 # rotation about Z axis
 158
 159                 # set the velocity
 160                 odom.child_frame_id = "base_footprint"
 161                 odom.twist.twist.linear.x = speed_trans
 162                 odom.twist.twist.linear.y = 0.0
 163                 odom.twist.twist.angular.z = speed_rot
 164                 odom.twist.covariance[0] = 1e-3 # x
 165                 odom.twist.covariance[7] = 1e-3 # y
 166                 odom.twist.covariance[14] = 1e6 # z
 167                 odom.twist.covariance[21] = 1e6 # rotation about X axis
 168                 odom.twist.covariance[28] = 1e6 # rotation about Y axis
 169                 odom.twist.covariance[35] = 0.03 # rotation about Z axis
 170
 171                 # publish the message
 172                 self.pub_odom.publish(odom)
 173
 174
 175         def set_speed(self, trans, rot):
 176                 i2c_write_reg(0x50, 0x50, struct.pack(">ff", trans, rot))
 177
 178         def cmdVelReceived(self, msg):
 179                 trans = msg.linear.x
 180                 rot = msg.angular.z # rad/s
 181                 self.set_speed(trans, rot)
 182
 183         # http://rn-wissen.de/wiki/index.php/Sensorarten#Sharp_GP2D12
 184         def get_dist_ir(self, num):
 185                 dev = i2c(0x52)
 186                 s = struct.pack("B", num)
 187                 dev.write(s)
 188                 dev.close()
 189
 190                 sleep(2e-6)
 191
 192                 dev = i2c(0x52)
 193                 s = dev.read(2)
 194                 dev.close()
 195
 196                 val = struct.unpack(">H", s)[0]
 197                 return val
 198
 199         def start_dist_srf(self, num):
 200                 dev = i2c(0x52)
 201                 s = struct.pack("B", num)
 202                 dev.write(s)
 203                 dev.close()
 204
 205         def read_dist_srf(self, num):
 206                 dev = i2c(0x52)
 207                 s = struct.pack("B", num)
 208                 dev.write(s)
 209                 dev.close()
 210
 211                 dev = i2c(0x52)
 212                 s = dev.read(2)
 213                 dev.close()
 214
 215                 return struct.unpack(">H", s)[0]/1000.0
 216
 217         def send_range(self, pub, frame_id, typ, dist, min_range, max_range, fov_deg):
 218                 msg = Range()
 219                 msg.header.stamp = rospy.Time.now()
 220                 msg.header.frame_id = frame_id
 221                 msg.radiation_type = typ
 222                 msg.field_of_view = fov_deg*pi/180
 223                 msg.min_range = min_range
 224                 msg.max_range = max_range
 225                 msg.range = dist
 226                 pub.publish(msg)
 227
 228         def get_dist_left(self):
 229                 if self.pub_range_left.get_num_connections() > 0:
 230                         dist = 30.553/(self.get_dist_ir(0x1) - -67.534)
 231                         self.send_range(self.pub_range_left, "ir_left", Range.INFRARED, dist, 0.04, 0.3, 1)
 232
 233         def get_dist_right(self):
 234                 if self.pub_range_right.get_num_connections() > 0:
 235                         dist = 17.4/(self.get_dist_ir(0x3) - 69)
 236                         self.send_range(self.pub_range_right, "ir_right", Range.INFRARED, dist, 0.04, 0.3, 1)
 237
 238         def get_dist_forward(self):
 239                 if self.pub_range_fwd.get_num_connections() > 0:
 240                         dist = self.read_dist_srf(0x15)
 241                         self.send_range(self.pub_range_fwd, "sonar_forward", Range.ULTRASOUND, dist, 0.04, 6, 30)
 242                         self.start_dist_srf(0x5) # get next value
 243
 244         def get_dist_backward(self):
 245                 if self.pub_range_bwd.get_num_connections() > 0:
 246                         dist = self.read_dist_srf(0x17)
 247                         self.send_range(self.pub_range_bwd, "sonar_backward", Range.ULTRASOUND, dist, 0.04, 6, 30)
 248                         self.start_dist_srf(0x7) # get next value
 249
 250
 251 if __name__ == "__main__":
 252         MoveBase()