LandDetector: Merged fixedwing and multicopter into one module handling both algorithms

1 files changed, 103 insertions, 0 deletions

diff --git a/src/modules/land_detector/FixedwingLandDetector.cpp b/src/modules/land_detector/FixedwingLandDetector.cpp
new file mode 100644
index 000000000..42735f38c
--- /dev/null
+++ b/src/modules/land_detector/FixedwingLandDetector.cpp
@@ -0,0 +1,103 @@
+/****************************************************************************
+ *
+ *   Copyright (c) 2013-2015 PX4 Development Team. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name PX4 nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/**
+ * @file FixedwingLandDetector.cpp
+ * Land detection algorithm for fixedwings
+ *
+ * @author Johan Jansen <jnsn.johan@gmail.com>
+ */
+
+#include "FixedwingLandDetector.h"
+ 
+#include <cmath>
+#include <drivers/drv_hrt.h>
+
+FixedwingLandDetector::FixedwingLandDetector() :
+        _vehicleLocalPositionSub(-1),
+        _vehicleLocalPosition({}),
+        _airspeedSub(-1),
+        _airspeed({}),
+
+        _velocity_xy_filtered(0.0f),
+        _velocity_z_filtered(0.0f),
+        _airspeed_filtered(0.0f),
+        _landDetectTrigger(0)
+{
+    //ctor
+}
+
+void FixedwingLandDetector::initialize()
+{
+    //Subscribe to local position and airspeed data
+    _vehicleLocalPositionSub = orb_subscribe(ORB_ID(vehicle_local_position));
+    _airspeedSub = orb_subscribe(ORB_ID(airspeed));
+}
+
+void FixedwingLandDetector::updateSubscriptions()
+{
+    orb_update(ORB_ID(vehicle_local_position), _vehicleLocalPositionSub, &_vehicleLocalPosition);
+    orb_update(ORB_ID(airspeed), _airspeedSub, &_airspeed);
+}
+
+bool FixedwingLandDetector::update()
+{
+    //First poll for new data from our subscriptions
+    updateSubscriptions();
+
+    const uint64_t now = hrt_absolute_time();
+    bool landDetected = false;
+
+    //TODO: reset filtered values on arming?
+    _velocity_xy_filtered = 0.95f * _velocity_xy_filtered + 0.05f * sqrtf(_vehicleLocalPosition.vx *
+                _vehicleLocalPosition.vx + _vehicleLocalPosition.vy * _vehicleLocalPosition.vy);
+    _velocity_z_filtered = 0.95f * _velocity_z_filtered + 0.05f * fabsf(_vehicleLocalPosition.vz);
+    _airspeed_filtered = 0.95f * _airspeed_filtered + 0.05f * _airspeed.true_airspeed_m_s;
+
+    /* crude land detector for fixedwing */
+    if (_velocity_xy_filtered < FW_LAND_DETECTOR_VELOCITY_MAX
+        && _velocity_z_filtered < FW_LAND_DETECTOR_CLIMBRATE_MAX
+        && _airspeed_filtered < FW_LAND_DETECTOR_AIRSPEED_MAX) {
+
+        //These conditions need to be stable for a period of time before we trust them
+        if (now > _landDetectTrigger) {
+            landDetected = true;
+        }
+
+    } else {
+        //reset land detect trigger
+        _landDetectTrigger = now + FW_LAND_DETECTOR_TRIGGER_TIME;
+    }
+
+    return landDetected;
+}