2 import roslib; roslib.load_manifest('roboint')
6 from geometry_msgs.msg import Twist, TransformStamped, Point32
7 from sensor_msgs.msg import LaserScan
8 from nav_msgs.msg import Odometry
9 from roboint.msg import Motor
10 from roboint.msg import Inputs
15 rospy.init_node('robo_explorer')
21 self.tf_broadcaster = tf.broadcaster.TransformBroadcaster()
22 self.last_time = rospy.Time.now()
27 # fake laser scan with ultra sonic range finder
28 self.enable_ultrasonic_laser = bool(rospy.get_param('~ultrasonic_laser', "True"))
29 # Distance between both wheels in meter (18.55cm)
30 self.wheel_dist = float(rospy.get_param('~wheel_dist', "0.1855"))
31 # Size of wheel Diameter in meter (5.15cm) * gear ratio (0.5) = 2.575cm
32 self.wheel_size = float(rospy.get_param('~wheel_size', "0.02575"))
33 # Speed to PWM equation gradiant (The m in pwm = speed*m+b)
34 self.speed_gradiant = float(rospy.get_param('~speed_gradiant', "64.3"))
35 # Speed to PWM equation constant (The b in pwm = speed*m+b)
36 self.speed_constant = float(rospy.get_param('~speed_constant', "-1.7"))
38 self.pub_motor = rospy.Publisher("ft/set_motor", Motor)
39 if self.enable_ultrasonic_laser:
40 self.pub_scan = rospy.Publisher("scan", LaserScan)
41 self.pub_odom = rospy.Publisher("odom", Odometry)
43 rospy.Subscriber("cmd_vel", Twist, self.cmdVelReceived)
44 rospy.Subscriber("ft/get_inputs", Inputs, self.inputsReceived)
48 def inputsReceived(self, msg):
49 current_time = rospy.Time.now()
51 self.update_odometry(msg, current_time)
52 if (current_time - self.last_time).to_nsec() > 100e6: # send every 100ms
53 self.send_odometry(msg, current_time)
54 if self.enable_ultrasonic_laser:
55 self.send_laser_scan(msg, current_time)
56 self.last_time = current_time
58 def update_odometry(self, msg, current_time):
59 in_now = msg.input[:2]
60 if self.last_in is not None:
61 in_diff = [abs(a - b) for a, b in zip(in_now, self.last_in)] # get changed inputs
62 # fix in_diff from actual motor direction
63 if msg.output[1] > 0: # left reverse
64 in_diff[0] = -in_diff[0]
65 elif msg.output[0] == 0 and msg.output[1] == 0: # left stop
67 if msg.output[3] > 0: # right reverse
68 in_diff[1] = -in_diff[1]
69 elif msg.output[2] == 0 and msg.output[3] == 0: # right stop
72 dist_dir = (in_diff[1] - in_diff[0])*self.wheel_size*pi/8 # steps_changed in different direction => m
73 delta_alpha = dist_dir/self.wheel_dist
75 dist = (in_diff[0] + in_diff[1])/2.0*self.wheel_size*pi/8 # steps_changed same direction => m
77 delta_x = cos(self.alpha + delta_alpha/2)*dist
78 delta_y = sin(self.alpha + delta_alpha/2)*dist
80 self.alpha += delta_alpha
83 elif self.alpha < -2*pi:
90 def send_odometry(self, msg, current_time):
92 dt = (current_time - self.last_time).to_sec()
93 vx = sqrt((self.x - self.x_last)**2 + (self.y - self.y_last)**2) / dt
94 if (msg.output[0]-msg.output[1] + msg.output[2]-msg.output[3]) < 0:
97 valpha = (self.alpha - self.alpha_last) / dt
100 self.alpha_last = self.alpha
102 # since all odometry is 6DOF we'll need a quaternion created from yaw
103 odom_quat = tf.transformations.quaternion_from_euler(0, 0, self.alpha)
105 # first, we'll publish the transform over tf
106 self.tf_broadcaster.sendTransform((self.x, self.y, 0.0), odom_quat, current_time, "base_link", "odom")
108 # next, we'll publish the odometry message over ROS
110 odom.header.stamp = current_time
111 odom.header.frame_id = "/odom"
114 odom.pose.pose.position.x = self.x
115 odom.pose.pose.position.y = self.y
116 odom.pose.pose.position.z = 0.0
117 odom.pose.pose.orientation.x = odom_quat[0]
118 odom.pose.pose.orientation.y = odom_quat[1]
119 odom.pose.pose.orientation.z = odom_quat[2]
120 odom.pose.pose.orientation.w = odom_quat[3]
123 odom.child_frame_id = "base_link"
124 odom.twist.twist.linear.x = vx
125 odom.twist.twist.linear.y = 0.0
126 odom.twist.twist.angular.z = valpha
128 # publish the message
129 self.pub_odom.publish(odom)
131 def send_laser_scan(self, msg, current_time):
132 # first, we'll publish the transform over tf
133 self.tf_broadcaster.sendTransform((0.06, 0.0, 0.0), (0.0, 0.0, 0.0, 1.0), current_time, "scan", "base_link")
135 # actually ultra sonic range finder
136 num_points = 60 # The base planner needs at least 30 points to work in the default config
137 opening_angle = 30*pi/180 # each side
139 scan.header.stamp = current_time
140 scan.header.frame_id = "/scan"
141 scan.angle_min = -opening_angle
142 scan.angle_max = opening_angle
143 scan.angle_increment = (2*opening_angle)/num_points
144 scan.time_increment = 0.0
147 for i in range(num_points):
148 scan.ranges.append(msg.d1/100.0)
149 #scan.intensities.append(0.5)
150 #scan.intensities.append(1.0)
151 #scan.intensities.append(0.5)
152 self.pub_scan.publish(scan)
154 # test with rostopic pub -1 cmd_vel geometry_msgs/Twist '[0, 0, 0]' '[0, 0, 0]'
155 def cmdVelReceived(self, msg):
157 rot = msg.angular.z # rad/s
159 # handle rotation as offset to speeds
160 speed_offset = (rot * self.wheel_dist)/2.0 # m/s
164 wish_speed_left = trans - speed_offset
165 if abs(wish_speed_left) > 0:
166 speed_l = self.speed_gradiant*abs(wish_speed_left) + self.speed_constant
167 if wish_speed_left < 0:
170 wish_speed_right = trans + speed_offset
171 if abs(wish_speed_right) > 0:
172 speed_r = self.speed_gradiant*abs(wish_speed_right) + self.speed_constant
173 if wish_speed_right < 0:
177 if speed_l < -7: speed_l = -7
178 elif speed_l > 7: speed_l = 7
179 if speed_r < -7: speed_r = -7
180 elif speed_r > 7: speed_r = 7
182 #print "Speed wanted: %.2f m/s %.2f rad/s, set: %d %d" % (trans, rot, round(speed_l), round(speed_r))
186 outmsg.speed = round(speed_l)
187 self.pub_motor.publish(outmsg)
191 outmsg.speed = round(speed_r)
192 self.pub_motor.publish(outmsg)
194 if __name__ == '__main__':