AP_Scripting: add rover-set-steering-and-throttle example script

libraries/AP_Scripting/examples/rover-set-steering-and-throttle.lua

@@ -0,0 +1,60 @@
+-- cause a rover to drive in a figure of eight pattern by directly controlling steering and throttle
+--
+-- CAUTION: This script only works for Rover
+-- this script waits for the vehicle to be armed and RC6 input > 1800 and then:
+--    a) switches to Guided mode
+--    b) increases throttle to 30% and turns right at 20% for 10 seconds
+--    c) keep throttle at 30% and turns left at 20% for 10 seconds
+--    d) switches to Hold mode
+
+local stage = 0
+local stage_counter = 0
+local rover_guided_mode_num = 15
+local rover_hold_mode_num = 4
+
+-- the main update function that directly sets throttle and steering out to drive a figure of eight pattern
+function update()
+  if not arming:is_armed() then -- reset state when disarmed
+    stage = 0
+    stage_counter = 0
+  else
+    pwm6 = rc:get_pwm(6)
+    if pwm6 and pwm6 > 1800 then    -- check if RC6 input has moved high
+      if (stage == 0) then          -- change to guided mode
+        if (vehicle:set_mode(rover_guided_mode_num)) then     -- change to Guided mode
+          stage = stage + 1
+          stage_counter = 0
+        end
+      elseif (stage == 1) then      -- Stage1: increase throttle to 30% and turn right 20%
+        if (vehicle:set_steering_and_throttle(0.2, 0.3)) then
+          stage_counter = stage_counter + 1
+          if (stage_counter >= 10) then
+            stage = stage + 1
+            stage_counter = 0
+          end
+        end
+      elseif (stage == 2) then      -- Stage2: keep throttle at 30% and turn left 20%
+        if (vehicle:set_steering_and_throttle(-0.2, 0.3)) then
+          stage_counter = stage_counter + 1
+          if (stage_counter >= 10) then
+            stage = stage + 1
+            stage_counter = 0
+          end
+        end
+      elseif (stage == 3) then      -- Stage3: change to Hold mode
+        vehicle:set_mode(rover_hold_mode_num)
+        stage = stage + 1
+        gcs:send_text(0, "finished, switching to Hold")
+      end
+    else -- RC6 has been moved low
+      if stage > 3 then 
+        stage = 0
+        stage_counter = 0
+      end
+    end
+  end
+
+  return update, 1000
+end
+
+return update()