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 from sensor_msgs.msg import Imu
  13
  14 WHEEL_DIST = 0.248
  15
  16 class MoveBase:
  17         def __init__(self):
  18                 rospy.init_node('wild_thumper_move_base')
  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.set_speed(0, 0)
  29                 rospy.loginfo("Init done")
  30                 i2c_write_reg(0x50, 0x90, struct.pack("BB", 1, 1)) # switch direction
  31                 self.handicap_last = (-1, -1)
  32                 self.run()
  33
  34         def run(self):
  35                 rate = rospy.Rate(20.0)
  36                 reset_val = self.get_reset()
  37                 rospy.loginfo("Reset Status: 0x%x" % reset_val)
  38                 while not rospy.is_shutdown():
  39                         #print struct.unpack(">B", i2c_read_reg(0x50, 0xA2, 1))[0] # count test
  40                         self.get_tle_err()
  41                         self.get_odom()
  42                         self.get_voltage()
  43                         #self.get_dist_forward()
  44                         #self.get_dist_backward()
  45                         #self.get_dist_left()
  46                         #self.get_dist_right()
  47                         rate.sleep()
  48
  49         def set_motor_handicap(self, front, aft): # percent
  50                 if self.handicap_last != (front, aft):
  51                         i2c_write_reg(0x50, 0x94, struct.pack(">bb", front, aft))
  52                         self.handicap_last = (front, aft)
  53
  54         def imuReceived(self, msg):
  55                 (roll, pitch, yaw) = tf.transformations.euler_from_quaternion(msg.orientation.__getstate__())
  56                 if pitch > 30*pi/180:
  57                         val = (100.0/65)*abs(pitch)*180/pi
  58                         self.set_motor_handicap(0, int(val))
  59                 elif pitch < -30*pi/180:
  60                         val = (100.0/65)*abs(pitch)*180/pi
  61                         self.set_motor_handicap(int(val), 0)
  62                 else:
  63                         self.set_motor_handicap(0, 0)
  64
  65         def get_reset(self):
  66                 reset = struct.unpack(">B", i2c_read_reg(0x50, 0xA0, 1))[0]
  67
  68                 msg = DiagnosticArray()
  69                 msg.header.stamp = rospy.Time.now()
  70                 stat = DiagnosticStatus()
  71                 stat.name = "Reset reason"
  72                 stat.level = DiagnosticStatus.ERROR if reset & 0x0c else DiagnosticStatus.OK
  73                 stat.message = "0x%02x" % reset
  74
  75                 stat.values.append(KeyValue("Watchdog Reset Flag", str(bool(reset & (1 << 3)))))
  76                 stat.values.append(KeyValue("Brown-out Reset Flag", str(bool(reset & (1 << 2)))))
  77                 stat.values.append(KeyValue("External Reset Flag", str(bool(reset & (1 << 1)))))
  78                 stat.values.append(KeyValue("Power-on Reset Flag", str(bool(reset & (1 << 0)))))
  79
  80                 msg.status.append(stat)
  81                 self.pub_diag.publish(msg)
  82                 return reset
  83
  84
  85         def get_tle_err(self):
  86                 err = struct.unpack(">B", i2c_read_reg(0x50, 0xA1, 1))[0]
  87
  88                 msg = DiagnosticArray()
  89                 msg.header.stamp = rospy.Time.now()
  90                 stat = DiagnosticStatus()
  91                 stat.name = "Motor: Error Status"
  92                 stat.level = DiagnosticStatus.ERROR if err else DiagnosticStatus.OK
  93                 stat.message = "0x%02x" % err
  94
  95                 stat.values.append(KeyValue("aft left", str(bool(err & (1 << 0)))))
  96                 stat.values.append(KeyValue("front left", str(bool(err & (1 << 1)))))
  97                 stat.values.append(KeyValue("front right", str(bool(err & (1 << 2)))))
  98                 stat.values.append(KeyValue("aft right", str(bool(err & (1 << 3)))))
  99
 100                 msg.status.append(stat)
 101                 self.pub_diag.publish(msg)
 102
 103         def get_voltage(self):
 104                 volt = struct.unpack(">h", i2c_read_reg(0x52, 0x09, 2))[0]/100.0
 105
 106                 msg = DiagnosticArray()
 107                 msg.header.stamp = rospy.Time.now()
 108                 stat = DiagnosticStatus()
 109                 stat.name = "Voltage"
 110                 stat.level = DiagnosticStatus.ERROR if volt < 7 else DiagnosticStatus.OK
 111                 stat.message = "%.2fV" % volt
 112
 113                 msg.status.append(stat)
 114                 self.pub_diag.publish(msg)
 115
 116
 117         def get_odom(self):
 118                 posx, posy, angle = struct.unpack(">fff", i2c_read_reg(0x50, 0x40, 12))
 119                 speed_trans, speed_rot = struct.unpack(">ff", i2c_read_reg(0x50, 0x38, 8))
 120                 current_time = rospy.Time.now()
 121
 122                 # since all odometry is 6DOF we'll need a quaternion created from yaw
 123                 odom_quat = tf.transformations.quaternion_from_euler(0, 0, angle)
 124
 125                 # first, we'll publish the transform over tf
 126                 if self.tf_broadcaster is not None:
 127                         self.tf_broadcaster.sendTransform((posx, posy, 0.0), odom_quat, current_time, "base_footprint", "odom")
 128
 129                 # next, we'll publish the odometry message over ROS
 130                 odom = Odometry()
 131                 odom.header.stamp = current_time
 132                 odom.header.frame_id = "/odom"
 133
 134                 # set the position
 135                 odom.pose.pose.position.x = posx
 136                 odom.pose.pose.position.y = posy
 137                 odom.pose.pose.position.z = 0.0
 138                 odom.pose.pose.orientation.x = odom_quat[0]
 139                 odom.pose.pose.orientation.y = odom_quat[1]
 140                 odom.pose.pose.orientation.z = odom_quat[2]
 141                 odom.pose.pose.orientation.w = odom_quat[3]
 142                 odom.pose.covariance[0] = 1e-3 # x
 143                 odom.pose.covariance[7] = 1e-3 # y
 144                 odom.pose.covariance[14] = 1e6 # z
 145                 odom.pose.covariance[21] = 1e6 # rotation about X axis
 146                 odom.pose.covariance[28] = 1e6 # rotation about Y axis
 147                 odom.pose.covariance[35] = 0.1 # rotation about Z axis
 148
 149                 # set the velocity
 150                 odom.child_frame_id = "base_footprint"
 151                 odom.twist.twist.linear.x = speed_trans
 152                 odom.twist.twist.linear.y = 0.0
 153                 odom.twist.twist.angular.z = speed_rot
 154                 odom.twist.covariance[0] = 1e-3 # x
 155                 odom.twist.covariance[7] = 1e-3 # y
 156                 odom.twist.covariance[14] = 1e6 # z
 157                 odom.twist.covariance[21] = 1e6 # rotation about X axis
 158                 odom.twist.covariance[28] = 1e6 # rotation about Y axis
 159                 odom.twist.covariance[35] = 0.1 # rotation about Z axis
 160
 161                 # publish the message
 162                 self.pub_odom.publish(odom)
 163
 164
 165         def set_speed(self, trans, rot):
 166                 i2c_write_reg(0x50, 0x50, struct.pack(">ff", trans, rot))
 167
 168         def cmdVelReceived(self, msg):
 169                 trans = msg.linear.x
 170                 rot = msg.angular.z # rad/s
 171                 self.set_speed(trans, rot)
 172
 173         # http://rn-wissen.de/wiki/index.php/Sensorarten#Sharp_GP2D12
 174         def get_dist_ir(self, num):
 175                 dev = i2c(0x52)
 176                 s = struct.pack("B", num)
 177                 dev.write(s)
 178                 dev.close()
 179
 180                 sleep(2e-6)
 181
 182                 dev = i2c(0x52)
 183                 s = dev.read(2)
 184                 dev.close()
 185
 186                 val = struct.unpack(">H", s)[0]
 187                 return 15221/(val - -276.42)/100;
 188
 189         def get_dist_srf(self, num):
 190                 dev = i2c(0x52)
 191                 s = struct.pack("B", num)
 192                 dev.write(s)
 193                 dev.close()
 194
 195                 sleep(50e-3)
 196
 197                 dev = i2c(0x52)
 198                 s = dev.read(2)
 199                 dev.close()
 200
 201                 return struct.unpack(">H", s)[0]/1000.0
 202
 203         def get_dist_left(self):
 204                 dist = self.get_dist_ir(0x1)
 205
 206         def get_dist_right(self):
 207                  dist = self.get_dist_ir(0x3)
 208
 209         def get_dist_forward(self):
 210                 dist = self.get_dist_srf(0x5)
 211
 212         def get_dist_backward(self):
 213                 dist = self.get_dist_srf(0x7)
 214
 215
 216 if __name__ == "__main__":
 217         MoveBase()