dwm1000: variance dependant on distance
authorErik Andresen <erik@vontaene.de>
Sun, 15 Jul 2018 09:32:35 +0000 (11:32 +0200)
committerErik Andresen <erik@vontaene.de>
Sun, 15 Jul 2018 09:32:35 +0000 (11:32 +0200)
scripts/dwm1000.py

index bf58657..15c4025 100755 (executable)
@@ -73,10 +73,10 @@ class DW1000(threading.Thread):
 
        def run(self):
                last_val = 10
-               while True:
+               while not rospy.is_shutdown():
                        val = self.get_value()
                        if abs(val - last_val)  > 10:
-                               print "Ignoring values too far apart %s: %.2f - %.2f" % (self.name, val, last_val)
+                               rospy.logwarn("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()
@@ -107,10 +107,6 @@ 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()
@@ -129,8 +125,14 @@ class Position:
 
                # run kalman if new measurements are valid
                if x != None and y != None:
+                       print "Var", self.filter_x.R, self.filter_y.R
                        x = self.filter_x.run(x)
                        y = self.filter_y.run(y)
+
+                       # Update covariance
+                       dist = np.linalg.norm([x, y])
+                       self.filter_x.R = np.polyval([0.017795,  -0.021832, 0.010968], dist)
+                       self.filter_y.R = np.polyval([0.0060314, -0.013387, 0.0065049], dist)
                else:
                        x = self.filter_x.x_est
                        y = self.filter_y.x_est
@@ -143,14 +145,14 @@ def handle_center_call(req):
        diff = dwleft.distance_valid() - dwright.distance_valid()
        dwleft.offset -= diff/2
        dwright.offset += diff/2
-       print "Centering to %.2f %.2f" % (dwleft.offset, dwright.offset)
+       rospy.loginfo("Centering to %.2f %.2f", dwleft.offset, dwright.offset)
        return DWM1000CenterResponse()
 
 if __name__ == "__main__":
-       rospy.init_node('DWM1000')
-       dwleft  = DW1000("uwb_dist_left",  0xc2, +0.02)
-       dwright = DW1000("uwb_dist_right", 0xc0, -0.02)
-       dist_l_r = 0.285
+       rospy.init_node('DWM1000', log_level=rospy.DEBUG)
+       dwleft  = DW1000("uwb_dist_left",  0xc2, +0.00)
+       dwright = DW1000("uwb_dist_right", 0xc0, -0.00)
+       dist_l_r = 0.285 # Distance between both DWM1000
        rate = rospy.Rate(10)
        pos = Position()
        tf_broadcaster = tf.broadcaster.TransformBroadcaster()
@@ -160,7 +162,7 @@ if __name__ == "__main__":
                dist_left = dwleft.distance_valid()
                dist_right = dwright.distance_valid()
                if dist_left == None or dist_right == None:
-                       print "no valid sensor update"
+                       rospy.logerr("no valid sensor update")
                        # run kalman prediction only
                        pos.filter(None, None)
                else:
@@ -176,14 +178,14 @@ if __name__ == "__main__":
                                else:
                                        dist_left += off/2
                                        dist_right -= off/2
-                       print "%.2f %.2f %.2f %.2f %s" % (dwleft.distance(), dwright.distance(), dist_left, dist_right, dir)
+                       rospy.logdebug("%.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
+                               rospy.logdebug("x=%.2f, y=%.2f", x, y)
                                # Rotate 90 deg
                                x, y = (y, -x)