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