autotest: add test for AUTO_LAND_TO_BRAKE

Having some terrain-based issues with BRAKE mode

Tools/autotest/ArduCopter_Tests/AUTO_LAND_TO_BRAKE/mission.txt

@@ -0,0 +1,19 @@
+QGC WPL 110
+0	0	0	16	0.000000	0.000000	0.000000	0.000000	-20.558323	-47.415722	931.809998	1
+1	0	3	22	0.000000	0.000000	0.000000	0.000000	0.000000	0.000000	35.000000	1
+2	0	3	16	1.000000	0.000000	0.000000	0.000000	-20.558323	-47.415722	35.000000	1
+3	0	3	16	0.000000	0.000000	0.000000	0.000000	-20.558152	-47.415520	35.000000	1
+4	0	3	16	0.000000	0.000000	0.000000	0.000000	-20.558317	-47.415059	35.000000	1
+5	0	3	16	0.000000	0.000000	0.000000	0.000000	-20.558746	-47.414832	35.000000	1
+6	0	3	16	1.000000	0.000000	0.000000	0.000000	-20.558941	-47.415046	35.000000	1
+7	0	3	21	0.000000	0.000000	0.000000	1.000000	-20.558941	-47.415046	0.000000	1
+8	0	0	211	0.000000	0.000000	0.000000	0.000000	0.000000	0.000000	0.000000	1
+9	0	0	93	5.000000	0.000000	0.000000	0.000000	0.000000	0.000000	0.000000	1
+10	0	3	22	0.000000	0.000000	0.000000	0.000000	0.000000	0.000000	35.000000	1
+11	0	0	178	0.000000	8.888889	0.000000	0.000000	0.000000	0.000000	0.000000	1
+12	0	3	16	1.000000	0.000000	0.000000	0.000000	-20.558941	-47.415046	35.000000	1
+13	0	3	16	0.000000	0.000000	0.000000	0.000000	-20.558746	-47.414832	35.000000	1
+14	0	3	16	0.000000	0.000000	0.000000	0.000000	-20.558317	-47.415059	35.000000	1
+15	0	3	16	0.000000	0.000000	0.000000	0.000000	-20.558152	-47.415520	35.000000	1
+16	0	3	16	1.000000	0.000000	0.000000	0.000000	-20.558323	-47.415722	35.000000	1
+17	0	3	21	0.000000	0.000000	0.000000	1.000000	-20.558323	-47.415722	0.000000	1

Tools/autotest/arducopter.py

@@ -8431,6 +8431,65 @@ class AutoTestCopter(AutoTest):
 
         self.wait_disarmed()
 
+    def AUTO_LAND_TO_BRAKE(self):
+        '''ensure terrain altitude is taken into account when braking'''
+        self.load_mission('mission.txt')
+        home_loc = self.get_home_tuple_from_mission("mission.txt")
+
+        self.set_parameters({
+            "PLND_ACC_P_NSE": 2.500000,
+            "PLND_ALT_MAX": 8.000000,
+            "PLND_ALT_MIN": 0.750000,
+            "PLND_BUS": -1,
+            "PLND_CAM_POS_X": 0.000000,
+            "PLND_CAM_POS_Y": 0.000000,
+            "PLND_CAM_POS_Z": 0.000000,
+            "PLND_ENABLED": 1,
+            "PLND_EST_TYPE": 1,
+            "PLND_LAG": 0.020000,
+            "PLND_LAND_OFS_X": 0.000000,
+            "PLND_LAND_OFS_Y": 0.000000,
+            "PLND_OPTIONS": 0,
+            "PLND_RET_BEHAVE": 0,
+            "PLND_RET_MAX": 4,
+            "PLND_STRICT": 1,
+            "PLND_TIMEOUT": 4.000000,
+            "PLND_TYPE": 4,
+            "PLND_XY_DIST_MAX": 2.500000,
+            "PLND_YAW_ALIGN": 0.000000,
+
+            "SIM_PLD_ALT_LMT": 15.000000,
+            "SIM_PLD_DIST_LMT": 10.000000,
+            "SIM_PLD_ENABLE": 1,
+            "SIM_PLD_HEIGHT": 942.0000000,
+            "SIM_PLD_LAT": -20.558929,
+            "SIM_PLD_LON": -47.415035,
+            "SIM_PLD_RATE": 100,
+            "SIM_PLD_TYPE": 1,
+            "SIM_PLD_YAW": 87,
+
+            "SIM_SONAR_SCALE": 12,
+        })
+
+        self.set_analog_rangefinder_parameters()
+
+        self.customise_SITL_commandline([
+            "--home", "%s,%s,%s,%s" % home_loc
+        ])
+
+        self.set_parameter('AUTO_OPTIONS', 3)
+        self.change_mode('AUTO')
+        self.wait_ready_to_arm()
+        self.arm_vehicle()
+
+        self.wait_current_waypoint(7)
+        self.wait_altitude(10, 15, relative=True, timeout=60)
+        self.change_mode('BRAKE')
+        # monitor altitude here
+        self.wait_altitude(10, 15, relative=True, minimum_duration=20)
+        self.change_mode('AUTO')
+        self.wait_disarmed()
+
     # a wrapper around all the 1A,1B,1C..etc tests for travis
     def tests1(self):
         ret = ([])
@@ -9156,6 +9215,10 @@ class AutoTestCopter(AutoTest):
                  "Change speed during misison using waypoint items",
                  self.DO_CHANGE_SPEED),
 
+            Test("AUTO_LAND_TO_BRAKE",
+                 "Change to LAND while descending in AUTO land phase",
+                 self.AUTO_LAND_TO_BRAKE),
+
             Test("WPNAV_SPEED",
                  "Change speed during misison",
                  self.WPNAV_SPEED),