Copter: Add adjustable pre-arm check for minimum air pressure

3drobotics · Sep 15, 2016 · cd35922 · cd35922
1 parent b930c80
commit cd35922
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Showing 3 changed files with 21 additions and 1 deletion.
diff --git a/ArduCopter/Parameters.h b/ArduCopter/Parameters.h
@@ -139,7 +139,8 @@ class Parameters {
         k_param_altitude_limit,         // deprecated - remove
         k_param_fence,
         k_param_gps_glitch,             // deprecated
-        k_param_baro_glitch,            // 71 - deprecated
+        k_param_baro_glitch,            // deprecated
+        k_param_baro_launch_limit,   // 72
 
         //
         // 75: Singlecopter, CoaxCopter
@@ -362,6 +363,9 @@ class Parameters {
     AP_Int16        takeoff_trigger_dz;
     AP_Float        pilot_takeoff_alt;
 
+    // takeoff environmental limits
+    AP_Float        baro_launch_limit;      // If the barometric pressure is lower than this value, the copter will not arm - Pa
+
     // Thrust loss recovery
     //
     AP_Int16        spd_lim_rate_cmss;      // rate that the horizontal speed limit applied to guided mode demands is reduced - cm/s/s

diff --git a/ArduCopter/Parameters.pde b/ArduCopter/Parameters.pde
@@ -1096,6 +1096,15 @@ const AP_Param::Info var_info[] PROGMEM = {
     // @User: Standard
     GSCALAR(autotune_aggressiveness, "AUTOTUNE_AGGR", 0.1f),
 
+    // @Param: GND_PRESS_MIN
+    // @DisplayName: ground level air pressure minimum
+    // @Description: If the ground level air pressure is lower than this value, then the copter will not arm. This is used to prevent takeoff at high elevaton locations where air density is insuffient for safe flight.
+    // @Units: Pa
+    // @Range: 50000 80000
+    // @Increment: 1000
+    // @User: Advanced
+    GSCALAR(baro_launch_limit, "GND_PRESS_MIN", 80000.0f),
+
     AP_VAREND
 };
 

diff --git a/ArduCopter/motors.pde b/ArduCopter/motors.pde
@@ -252,6 +252,13 @@ static bool pre_arm_checks(bool display_failure)
             }
             return false;
         }
+        // check that we are below our launch service ceiling
+        if( barometer.get_pressure() < g.baro_launch_limit ) {
+            if (display_failure) {
+                gcs_send_text_P(SEVERITY_HIGH,PSTR("PreArm: Launch ceiling exceeded"));
+            }
+            return false;
+        }
         // Check baro & inav alt are within 1m if EKF is operating in an absolute position mode.
         // Do not check if intending to operate in a ground relative height mode as EKF will output a ground relative height
         // that may differ from the baro height due to baro drift.