author Erik Andresen Sun, 8 Jul 2018 08:34:10 +0000 (10:34 +0200) committer Erik Andresen Sun, 8 Jul 2018 08:34:10 +0000 (10:34 +0200)

index d36a5d2..a1dac53 100755 (executable)
@@ -9,6 +9,7 @@ import rospy
import tf
import numpy as np
from math import *
+from datetime import datetime
from i2c import i2c
from time import sleep
from std_msgs.msg import Float32
self.offset = offset
self.name = name
+               self.last_update = datetime.min

self.pub = rospy.Publisher(name, Float32, queue_size=16)

def distance(self):
return self.dist

+       # Returns each distance only if current
+       def distance_valid(self):
+               if (datetime.now() - self.last_update).seconds < 1:
+                       return self.dist
+               return None
+
def run(self):
last_val = 10
while True:
print "Ignoring values too far apart %s: %.2f - %.2f" % (self.name, val, last_val)
elif not isnan(val):
self.dist = val + self.offset
+                               self.last_update = datetime.now()
self.pub.publish(self.distance())
last_val = val
sleep(0.1)
@@ -97,6 +106,10 @@ class Position:
self.speed_y = msg.twist.twist.linear.y
self.speed_z = msg.twist.twist.angular.z

+       """
+       TODO:
+       - variance of kalman should be dependant on distance
+       """
def filter(self, x, y):
# Correct estimation with speed
current_time = rospy.Time.now()
@@ -113,9 +126,13 @@ class Position:
self.filter_x.x_est = pos[0]
self.filter_y.x_est = pos[1]

-               # run kalman
-               x = self.filter_x.run(x)
-               y = self.filter_y.run(y)
+               # run kalman if new measurements are valid
+               if x != None and y != None:
+                       x = self.filter_x.run(x)
+                       y = self.filter_y.run(y)
+               else:
+                       x = self.filter_x.x_est
+                       y = self.filter_y.x_est

self.last_time = current_time
return x,y
@@ -123,49 +140,57 @@ class Position:

if __name__ == "__main__":
rospy.init_node('DW1000')
-       dwleft  = DW1000("uwb_dist_left",  0xc2, +0.0)
-       dwright = DW1000("uwb_dist_right", 0xc0, -0.0)
+       dwleft  = DW1000("uwb_dist_left",  0xc2, +0.02)
+       dwright = DW1000("uwb_dist_right", 0xc0, -0.02)
dist_l_r = 0.285
rate = rospy.Rate(10)
pos = Position()

while not rospy.is_shutdown() and dwleft.is_alive() and dwright.is_alive():
-               dist_left = dwleft.distance()
-               dist_right = dwright.distance()
-               dir = "left" if (dist_left < dist_right) else "right"
-
-               diff = abs(dist_left - dist_right)
-               if diff >= dist_l_r:
-                       # difference to high, correct to maximum
-                       off = diff - dist_l_r + 0.01
-                       if dist_left > dist_right:
-                               dist_left -= off/2
-                               dist_right += off/2
+               dist_left = dwleft.distance_valid()
+               dist_right = dwright.distance_valid()
+               if dist_left == None or dist_right == None:
+                       print "no valid sensor update"
+                       # run kalman prediction only
+                       pos.filter(None, None)
+               else:
+                       dir = "left" if (dist_left < dist_right) else "right"
+
+                       diff = abs(dist_left - dist_right)
+                       if diff >= dist_l_r:
+                               # difference to high, correct to maximum
+                               off = diff - dist_l_r + 0.01
+                               if dist_left > dist_right:
+                                       dist_left -= off/2
+                                       dist_right += off/2
+                               else:
+                                       dist_left += off/2
+                                       dist_right -= off/2
+                       print "%.2f %.2f %.2f %.2f %s" % (dwleft.distance(), dwright.distance(), dist_left, dist_right, dir)
+
+                       a_r = (-dist_right**2 + dist_left**2 - dist_l_r**2) / (-2*dist_l_r)
+                       x = dist_l_r/2 - a_r
+                       t = dist_right**2 - a_r**2
+                       if t >= 0:
+                               y = sqrt(t)
+                               print x,y
+                               # Rotate 90 deg
+                               x, y = (y, -x)
+
+                               x, y = pos.filter(x, y)
+                               tf_broadcaster.sendTransform((x, y, 0.0), (0, 0, 0, 1), rospy.Time.now(), "uwb_beacon", "base_footprint")
+
+                               if VISULAIZE:
+                                       circle_left = plt.Circle((-dist_l_r/2, 0), dwleft.distance, color='red', fill=False)
+                                       circle_right = plt.Circle((dist_l_r/2, 0), dwright.distance, color='green', fill=False)
+                                       plt.grid(True)
+                                       plt.axis('scaled')
+                                       plt.show()
else:
-                               dist_left += off/2
-                               dist_right -= off/2
-               print "%.2f %.2f %.2f %.2f %s" % (dwleft.distance(), dwright.distance(), dist_left, dist_right, dir)
-
-               a_r = (-dist_right**2 + dist_left**2 - dist_l_r**2) / (-2*dist_l_r)
-               x = dist_l_r/2 - a_r
-               t = dist_right**2 - a_r**2
-               if t >= 0:
-                       y = sqrt(t)
-                       print x,y
-                       # Rotate 90 deg
-                       x, y = (y, -x)
-
-                       x, y = pos.filter(x, y)
-                       tf_broadcaster.sendTransform((x, y, 0.0), (0, 0, 0, 1), rospy.Time.now(), "uwb_beacon", "base_footprint")
-
-                       if VISULAIZE:
-                               circle_left = plt.Circle((-dist_l_r/2, 0), dwleft.distance, color='red', fill=False)
-                               circle_right = plt.Circle((dist_l_r/2, 0), dwright.distance, color='green', fill=False)