import roslib; roslib.load_manifest('roboint')
import rospy
import tf
-from math import sin, cos
+from math import sin, cos, pi
from geometry_msgs.msg import Twist, TransformStamped, Point32
-from sensor_msgs.msg import PointCloud
+from sensor_msgs.msg import LaserScan
from nav_msgs.msg import Odometry
from roboint.msg import Motor
from roboint.msg import Inputs
class RoboExplorer:
def __init__(self):
rospy.init_node('robo_explorer')
-
- rospy.Subscriber("cmd_vel", Twist, self.cmdVelReceived)
- rospy.Subscriber("ft/get_inputs", Inputs, self.inputsReceived)
-
- self.pub_motor = rospy.Publisher("ft/set_motor", Motor)
- self.pub_cloud = rospy.Publisher("point_cloud", PointCloud)
- self.pub_odom = rospy.Publisher("odom", Odometry)
+ self.wheel_dist = 0.188 # 18.8cm
+ self.wheel_size = 0.052*0.5 # 5.2cm; gear ration=0.5
self.speed = (0, 0)
self.x = 0
self.y = 0
- self.th = 0
- self.last_in = [0, 0]
- self.odom_broadcaster = tf.TransformBroadcaster()
+ self.alpha = 0
+ self.last_in = None
+ self.tf_broadcaster = tf.TransformBroadcaster()
self.last_time = rospy.Time.now()
+ self.input_count = 0
+ self.x_last = 0
+ self.y_last = 0
+ self.alpha_last = 0
+
+ self.pub_motor = rospy.Publisher("ft/set_motor", Motor)
+ self.pub_scan = rospy.Publisher("scan", LaserScan)
+ self.pub_odom = rospy.Publisher("odom", Odometry)
+
+ rospy.Subscriber("cmd_vel", Twist, self.cmdVelReceived)
+ rospy.Subscriber("ft/get_inputs", Inputs, self.inputsReceived)
rospy.spin()
def inputsReceived(self, msg):
current_time = rospy.Time.now()
+ self.input_count+=1
- cloud = PointCloud()
- cloud.header.stamp = current_time
- cloud.header.frame_id = "sensor_frame"
- cloud.points.append(Point32(msg.d1/10.0, 0, 0))
- self.pub_cloud.publish(cloud)
+ self.update_odometry(msg, current_time)
+ if self.input_count >= 10:
+ self.input_count = 0
+ self.send_odometry(msg, current_time)
+ self.send_laser_scan(msg, current_time)
- dt = (current_time - self.last_time).to_sec();
+ def update_odometry(self, msg, current_time):
in_now = msg.input[1:3]
- in_diff = [abs(a - b) for a, b in zip(in_now, self.last_in)] # get changed inputs
- if self.speed[0] < 0:
- in_diff[0] = -in_diff[0]
- if self.speed[1] < 0:
- in_diff[1] = -in_diff[1]
-
- self.diff_to_angle = 0.1 # TODO
- diff_si = in_diff # TODO
+ 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 self.speed[0] < 0:
+ in_diff[0] = -in_diff[0]
+ elif self.speed[0] == 0:
+ in_diff[0] = 0
+ if self.speed[1] < 0:
+ in_diff[1] = -in_diff[1]
+ elif self.speed[1] == 0:
+ 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
- delta_th = (diff_si[0] - diff_si[1]) * self.diff_to_angle
- self.th += delta_th
-
- movement = (diff_si[0] + diff_si[1])/2.0
- delta_x = cos(self.th)*movement
- delta_y = sin(self.th)*movement
- self.x += delta_x
- self.y += delta_y
+ self.last_in = in_now
+ def send_odometry(self, msg, current_time):
# speeds
- vx = delta_x / dt
- vy = delta_y / dt
- vth = delta_th / dt
+ dt = (current_time - self.last_time).to_sec()
+ vx = (self.x - self.x_last) / dt
+ vy = (self.y - self.y_last) / dt
+ valpha = (self.alpha - self.alpha_last) / dt
+ self.last_time = current_time
+ 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
- odom_trans = TransformStamped()
- odom_trans.header.stamp = current_time
- odom_trans.header.frame_id = "odom"
- odom_trans.child_frame_id = "base_link"
- odom_trans.transform.translation.x = self.x
- odom_trans.transform.translation.y = self.y
- odom_trans.transform.translation.z = 0.0
- odom_trans.transform.rotation = self.th
-
- ## send the transform
- #self.odom_broadcaster.sendTransform(odom_trans);
+ 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"
+ 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 = self.th
+ 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.child_frame_id = "base_link"
odom.twist.twist.linear.x = vx
odom.twist.twist.linear.y = vy
- odom.twist.twist.angular.z = vth
+ odom.twist.twist.angular.z = valpha
# publish the message
self.pub_odom.publish(odom)
-
- self.last_time = current_time
- self.last_in = in_now
-
-
+
+ def send_laser_scan(self, msg, current_time):
+ # first, we'll publish the transform over tf
+ self.tf_broadcaster.sendTransform((0.06, 0.0, 0.0), (0.0, 0.0, 0.0, 1.0), current_time, "scan", "base_link")
+
+ # actually ultra sonic range finder
+ num_points = 30
+ opening_angle = 30*pi/180 # each side
+ scan = LaserScan()
+ scan.header.stamp = current_time
+ scan.header.frame_id = "/scan"
+ scan.angle_min = -opening_angle
+ scan.angle_max = opening_angle
+ scan.angle_increment = (2*opening_angle)/num_points
+ scan.time_increment = 0.1/num_points
+ scan.range_min = 0.0
+ scan.range_max = 4.0
+ for i in range(num_points):
+ scan.ranges.append(msg.d1/100.0)
+ #scan.intensities.append(0.5)
+ #scan.intensities.append(1.0)
+ #scan.intensities.append(0.5)
+ self.pub_scan.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
-
- # speed steps = 7
- # max trans = 0.1m/s
- # max rot = 0.29rad/s
-
- speed_l = int(trans*7/0.1 - rot*7/0.29)
- speed_r = int(trans*7/0.1 + rot*7/0.29)
+ 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) > 1.7/64.3:
+ speed_l = 64.3*abs(wish_speed_left) - 1.7
+ if wish_speed_left < 0:
+ speed_l*=-1
+ speed_r = 0
+ wish_speed_right = trans + speed_offset
+ if abs(wish_speed_right) > 1.7/64.3:
+ speed_r = 64.3*abs(wish_speed_right) - 1.7
+ 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
outmsg = Motor()
outmsg.num = 1
- outmsg.speed = speed_l
+ outmsg.speed = round(speed_l)
self.pub_motor.publish(outmsg)
outmsg = Motor()
outmsg.num = 2
- outmsg.speed = speed_r
+ outmsg.speed = round(speed_r)
self.pub_motor.publish(outmsg)
self.speed = (speed_l, speed_r)
projects / ros_roboint.git / blobdiff