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                 self.tf_broadcaster = tf.broadcaster.TransformBroadcaster()
  22                 self.pub_odom = rospy.Publisher("odom", Odometry, queue_size=16)
  23                 self.pub_diag = rospy.Publisher("diagnostics", DiagnosticArray, queue_size=16)
  24                 self.set_speed(0, 0)
  25                 rospy.loginfo("Init done")
  26                 i2c_write_reg(0x50, 0x90, struct.pack("BB", 1, 1)) # switch direction
  27                 self.handicap_last = (-1, -1)
  28                 self.run()
  29
  30         def run(self):
  31                 rate = rospy.Rate(20.0)
  32                 reset_val = self.get_reset()
  33                 rospy.loginfo("Reset Status: 0x%x" % reset_val)
  34                 while not rospy.is_shutdown():
  35                         #print struct.unpack(">B", i2c_read_reg(0x50, 0xA2, 1))[0] # count test
  36                         self.get_tle_err()
  37                         self.get_odom()
  38                         self.get_voltage()
  39                         #self.get_dist_forward()
  40                         #self.get_dist_backward()
  41                         #self.get_dist_left()
  42                         #self.get_dist_right()
  43                         rate.sleep()
  44
  45         def set_motor_handicap(self, front, aft): # percent
  46                 if self.handicap_last != (front, aft):
  47                         i2c_write_reg(0x50, 0x94, struct.pack(">bb", front, aft))
  48                         self.handicap_last = (front, aft)
  49
  50         def imuReceived(self, msg):
  51                 (roll, pitch, yaw) = tf.transformations.euler_from_quaternion(msg.orientation.__getstate__())
  52                 if pitch > 30*pi/180:
  53                         val = (100.0/65)*abs(pitch)*180/pi
  54                         self.set_motor_handicap(0, int(val))
  55                 elif pitch < -30*pi/180:
  56                         val = (100.0/65)*abs(pitch)*180/pi
  57                         self.set_motor_handicap(int(val), 0)
  58                 else:
  59                         self.set_motor_handicap(0, 0)
  60
  61         def get_reset(self):
  62                 reset = struct.unpack(">B", i2c_read_reg(0x50, 0xA0, 1))[0]
  63
  64                 msg = DiagnosticArray()
  65                 msg.header.stamp = rospy.Time.now()
  66                 stat = DiagnosticStatus()
  67                 stat.name = "Reset reason"
  68                 stat.level = DiagnosticStatus.ERROR if reset & 0x0c else DiagnosticStatus.OK
  69                 stat.message = "0x%02x" % reset
  70
  71                 stat.values.append(KeyValue("Watchdog Reset Flag", str(bool(reset & (1 << 3)))))
  72                 stat.values.append(KeyValue("Brown-out Reset Flag", str(bool(reset & (1 << 2)))))
  73                 stat.values.append(KeyValue("External Reset Flag", str(bool(reset & (1 << 1)))))
  74                 stat.values.append(KeyValue("Power-on Reset Flag", str(bool(reset & (1 << 0)))))
  75
  76                 msg.status.append(stat)
  77                 self.pub_diag.publish(msg)
  78                 return reset
  79
  80
  81         def get_tle_err(self):
  82                 err = struct.unpack(">B", i2c_read_reg(0x50, 0xA1, 1))[0]
  83
  84                 msg = DiagnosticArray()
  85                 msg.header.stamp = rospy.Time.now()
  86                 stat = DiagnosticStatus()
  87                 stat.name = "Motor: Error Status"
  88                 stat.level = DiagnosticStatus.ERROR if err else DiagnosticStatus.OK
  89                 stat.message = "0x%02x" % err
  90
  91                 stat.values.append(KeyValue("aft left", str(bool(err & (1 << 0)))))
  92                 stat.values.append(KeyValue("front left", str(bool(err & (1 << 1)))))
  93                 stat.values.append(KeyValue("front right", str(bool(err & (1 << 2)))))
  94                 stat.values.append(KeyValue("aft right", str(bool(err & (1 << 3)))))
  95
  96                 msg.status.append(stat)
  97                 self.pub_diag.publish(msg)
  98
  99         def get_voltage(self):
 100                 volt = struct.unpack(">h", i2c_read_reg(0x52, 0x09, 2))[0]/100.0
 101
 102                 msg = DiagnosticArray()
 103                 msg.header.stamp = rospy.Time.now()
 104                 stat = DiagnosticStatus()
 105                 stat.name = "Voltage"
 106                 stat.level = DiagnosticStatus.ERROR if volt < 7 else DiagnosticStatus.OK
 107                 stat.message = "%.2fV" % volt
 108
 109                 msg.status.append(stat)
 110                 self.pub_diag.publish(msg)
 111
 112
 113         def get_odom(self):
 114                 posx, posy, angle = struct.unpack(">fff", i2c_read_reg(0x50, 0x40, 12))
 115                 speed_trans, speed_rot = struct.unpack(">ff", i2c_read_reg(0x50, 0x38, 8))
 116                 current_time = rospy.Time.now()
 117
 118                 # since all odometry is 6DOF we'll need a quaternion created from yaw
 119                 odom_quat = tf.transformations.quaternion_from_euler(0, 0, angle)
 120
 121                 # first, we'll publish the transform over tf
 122                 self.tf_broadcaster.sendTransform((posx, posy, 0.0), odom_quat, current_time, "base_link", "odom")
 123
 124                 # next, we'll publish the odometry message over ROS
 125                 odom = Odometry()
 126                 odom.header.stamp = current_time
 127                 odom.header.frame_id = "/odom"
 128
 129                 # set the position
 130                 odom.pose.pose.position.x = posx
 131                 odom.pose.pose.position.y = posy
 132                 odom.pose.pose.position.z = 0.0
 133                 odom.pose.pose.orientation.x = odom_quat[0]
 134                 odom.pose.pose.orientation.y = odom_quat[1]
 135                 odom.pose.pose.orientation.z = odom_quat[2]
 136                 odom.pose.pose.orientation.w = odom_quat[3]
 137
 138                 # set the velocity
 139                 odom.child_frame_id = "base_link"
 140                 odom.twist.twist.linear.x = speed_trans
 141                 odom.twist.twist.linear.y = 0.0
 142                 odom.twist.twist.angular.z = speed_rot
 143
 144                 # publish the message
 145                 self.pub_odom.publish(odom)
 146
 147
 148         def set_speed(self, trans, rot):
 149                 i2c_write_reg(0x50, 0x50, struct.pack(">ff", trans, rot))
 150
 151         def cmdVelReceived(self, msg):
 152                 trans = msg.linear.x
 153                 rot = msg.angular.z # rad/s
 154                 self.set_speed(trans, rot)
 155
 156         # http://rn-wissen.de/wiki/index.php/Sensorarten#Sharp_GP2D12
 157         def get_dist_ir(self, num):
 158                 dev = i2c(0x52)
 159                 s = struct.pack("B", num)
 160                 dev.write(s)
 161                 dev.close()
 162
 163                 sleep(2e-6)
 164
 165                 dev = i2c(0x52)
 166                 s = dev.read(2)
 167                 dev.close()
 168
 169                 val = struct.unpack(">H", s)[0]
 170                 return 15221/(val - -276.42)/100;
 171
 172         def get_dist_srf(self, num):
 173                 dev = i2c(0x52)
 174                 s = struct.pack("B", num)
 175                 dev.write(s)
 176                 dev.close()
 177
 178                 sleep(50e-3)
 179
 180                 dev = i2c(0x52)
 181                 s = dev.read(2)
 182                 dev.close()
 183
 184                 return struct.unpack(">H", s)[0]/1000.0
 185
 186         def get_dist_left(self):
 187                 dist = self.get_dist_ir(0x1)
 188
 189         def get_dist_right(self):
 190                  dist = self.get_dist_ir(0x3)
 191
 192         def get_dist_forward(self):
 193                 dist = self.get_dist_srf(0x5)
 194
 195         def get_dist_backward(self):
 196                 dist = self.get_dist_srf(0x7)
 197
 198
 199 if __name__ == "__main__":
 200         MoveBase()