#!/usr/bin/env python
import roslib; roslib.load_manifest('roboint')
import rospy
-import tf
from math import *
-from geometry_msgs.msg import Twist, TransformStamped, Point32, PoseWithCovarianceStamped
from sensor_msgs.msg import Range
-from nav_msgs.msg import Odometry
-from roboint.msg import Motor
from roboint.msg import Inputs
def __init__(self):
rospy.init_node('robo_explorer')
- self.x = 0
- self.y = 0
- self.alpha = 0
- self.last_in = None
- self.tf_broadcaster = tf.broadcaster.TransformBroadcaster()
self.last_time = rospy.Time.now()
- self.x_last = 0
- self.y_last = 0
- self.alpha_last = 0
-
- # Distance between both wheels in meter (18.55cm)
- self.wheel_dist = float(rospy.get_param('~wheel_dist', "0.1855"))
- # Size of wheel Diameter in meter (5.15cm) * gear ratio (0.5) = 2.575cm
- self.wheel_size = float(rospy.get_param('~wheel_size', "0.02575"))
- # Speed to PWM equation gradiant (The m in pwm = speed*m+b)
- self.speed_gradiant = float(rospy.get_param('~speed_gradiant', "64.3"))
- # Speed to PWM equation constant (The b in pwm = speed*m+b)
- self.speed_constant = float(rospy.get_param('~speed_constant', "-1.7"))
-
- self.pub_motor = rospy.Publisher("ft/set_motor", Motor, queue_size=16)
self.pub_sonar = rospy.Publisher("sonar", Range, queue_size=16)
- self.pub_odom = rospy.Publisher("odom", Odometry, queue_size=16)
-
- rospy.Subscriber("cmd_vel", Twist, self.cmdVelReceived)
rospy.Subscriber("ft/get_inputs", Inputs, self.inputsReceived)
- rospy.Subscriber("initialpose", PoseWithCovarianceStamped, self.posReceived)
rospy.spin()
- def posReceived(self, msg):
- self.x = msg.pose.pose.position.x
- self.y = msg.pose.pose.position.y
- orientation = msg.pose.pose.orientation
- angles = tf.transformations.euler_from_quaternion([orientation.x, orientation.y, orientation.z, orientation.w])
- self.alpha = angles[2]
-
def inputsReceived(self, msg):
current_time = rospy.Time.now()
- self.update_odometry(msg, current_time)
+ #self.update_odometry(msg, current_time)
if (current_time - self.last_time).to_nsec() > 100e6: # send every 100ms
- self.send_odometry(msg, current_time)
+ #self.send_odometry(msg, current_time)
self.send_range(msg, current_time)
self.last_time = current_time
- def update_odometry(self, msg, current_time):
- in_now = msg.input[:2]
- if self.last_in is not None:
- in_diff = [abs(a - b) for a, b in zip(in_now, self.last_in)] # get changed inputs
- # fix in_diff from actual motor direction
- if msg.output[1] > 0: # left reverse
- in_diff[0] = -in_diff[0]
- elif msg.output[0] == 0 and msg.output[1] == 0: # left stop
- in_diff[0] = 0
- if msg.output[3] > 0: # right reverse
- in_diff[1] = -in_diff[1]
- elif msg.output[2] == 0 and msg.output[3] == 0: # right stop
- in_diff[1] = 0
-
- dist_dir = (in_diff[1] - in_diff[0]) * self.wheel_size*pi/8 # steps_changed in different direction => m
- delta_alpha = dist_dir/self.wheel_dist
-
- dist = (in_diff[0] + in_diff[1])/2.0 * self.wheel_size*pi/8 # steps_changed same direction => m
-
- delta_x = cos(self.alpha + delta_alpha/2)*dist
- delta_y = sin(self.alpha + delta_alpha/2)*dist
-
- self.alpha += delta_alpha
- if self.alpha > 2*pi:
- self.alpha -= 2*pi
- elif self.alpha < -2*pi:
- self.alpha += 2*pi
- self.x += delta_x
- self.y += delta_y
-
- self.last_in = in_now
-
- def send_odometry(self, msg, current_time):
- # speeds
- dt = (current_time - self.last_time).to_sec()
- vx = sqrt((self.x - self.x_last)**2 + (self.y - self.y_last)**2) / dt
- if (msg.output[0]-msg.output[1] + msg.output[2]-msg.output[3]) < 0:
- # moving backward
- vx*=-1
- valpha = (self.alpha - self.alpha_last) / dt
- self.x_last = self.x
- self.y_last = self.y
- self.alpha_last = self.alpha
-
- # since all odometry is 6DOF we'll need a quaternion created from yaw
- odom_quat = tf.transformations.quaternion_from_euler(0, 0, self.alpha)
-
- # first, we'll publish the transform over tf
- self.tf_broadcaster.sendTransform((self.x, self.y, 0.0), odom_quat, current_time, "base_link", "odom")
-
- # next, we'll publish the odometry message over ROS
- odom = Odometry()
- odom.header.stamp = current_time
- odom.header.frame_id = "/odom"
-
- # set the position
- odom.pose.pose.position.x = self.x
- odom.pose.pose.position.y = self.y
- odom.pose.pose.position.z = 0.0
- odom.pose.pose.orientation.x = odom_quat[0]
- odom.pose.pose.orientation.y = odom_quat[1]
- odom.pose.pose.orientation.z = odom_quat[2]
- odom.pose.pose.orientation.w = odom_quat[3]
-
- # set the velocity
- odom.child_frame_id = "base_link"
- odom.twist.twist.linear.x = vx
- odom.twist.twist.linear.y = 0.0
- odom.twist.twist.angular.z = valpha
-
- # publish the message
- self.pub_odom.publish(odom)
-
def send_range(self, msg, current_time):
# ultra sonic range finder
scan = Range()
scan.range = msg.d1/100.0
self.pub_sonar.publish(scan)
- # test with rostopic pub -1 cmd_vel geometry_msgs/Twist '[0, 0, 0]' '[0, 0, 0]'
- def cmdVelReceived(self, msg):
- trans = msg.linear.x
- rot = msg.angular.z # rad/s
-
- # handle rotation as offset to speeds
- speed_offset = (rot * self.wheel_dist)/2.0 # m/s
-
- # handle translation
- speed_l = 0
- wish_speed_left = trans - speed_offset
- if abs(wish_speed_left) > 0:
- speed_l = self.speed_gradiant*abs(wish_speed_left) + self.speed_constant
- if wish_speed_left < 0:
- speed_l*=-1
- speed_r = 0
- wish_speed_right = trans + speed_offset
- if abs(wish_speed_right) > 0:
- speed_r = self.speed_gradiant*abs(wish_speed_right) + self.speed_constant
- if wish_speed_right < 0:
- speed_r*=-1
-
- # check limits
- if speed_l < -7: speed_l = -7
- elif speed_l > 7: speed_l = 7
- if speed_r < -7: speed_r = -7
- elif speed_r > 7: speed_r = 7
-
- #print "Speed wanted: %.2f m/s %.2f rad/s, set: %d %d" % (trans, rot, round(speed_l), round(speed_r))
-
- outmsg = Motor()
- outmsg.num = 0
- outmsg.speed = round(speed_l)
- self.pub_motor.publish(outmsg)
-
- outmsg = Motor()
- outmsg.num = 1
- outmsg.speed = round(speed_r)
- self.pub_motor.publish(outmsg)
-
if __name__ == '__main__':
RoboExplorer()
projects / ros_roboint.git / blobdiff