commander: check center throttle for POSCTL/ALTCTL

When flying POSCTL and ALTCTL the throttle stick is usually spring
loaded and therefore centered. Therefore, it makes more sense to check
for above center instead of above low.

src/modules/commander/Commander.cpp

@@ -837,17 +837,23 @@ Commander::handle_command(vehicle_status_s *status_local, const vehicle_command_
 							break;
 						}
 
-						// Refuse to arm if in manual with non-zero throttle
-						if (cmd_arms
-						    && (status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_POSCTL
-							|| status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_ALTCTL
-							|| status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_MANUAL
-							|| status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_ACRO
-							|| status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_STAB
-							|| status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_RATTITUDE)
-						    && (sp_man.z > 0.1f)) {
-
-							mavlink_log_critical(&mavlink_log_pub, "Arming denied! Manual throttle not zero");
+						const bool throttle_above_low = (sp_man.z > 0.1f);
+						const bool throttle_above_center = (sp_man.z > 0.6f);
+
+						if (cmd_arms && throttle_above_center &&
+							(status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_POSCTL ||
+							 status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_ALTCTL)) {
+							mavlink_log_critical(&mavlink_log_pub, "Arming denied! Throttle not centered");
+							cmd_result = vehicle_command_s::VEHICLE_CMD_RESULT_DENIED;
+							break;
+						}
+
+						if (cmd_arms && throttle_above_low &&
+							(status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_MANUAL ||
+							 status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_ACRO ||
+							 status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_STAB ||
+							 status_local->nav_state == vehicle_status_s::NAVIGATION_STATE_RATTITUDE)) {
+							mavlink_log_critical(&mavlink_log_pub, "Arming denied! Throttle not zero");
 							cmd_result = vehicle_command_s::VEHICLE_CMD_RESULT_DENIED;
 							break;
 						}