commander: add 'commander arm -f' command to force arming

This allows to bypass preflight and prearm checks.
During development there are regular cases where I just want to arm the
board/vehicle no matter what, and the preflight checks are guaranteed to
fail (e.g. sensors uncalibrated, inconsistent, powered via USB, etc.).
Allowing an easy and quick way to arm (assuming you know what you are
doing) helps to speed up development considerably and is less frustrating.

src/modules/commander/Commander.cpp

@@ -200,7 +200,7 @@ void print_status();
 
 bool shutdown_if_allowed();
 
-transition_result_t arm_disarm(bool arm, orb_advert_t *mavlink_log_pub, const char *armedBy);
+transition_result_t arm_disarm(bool arm, bool run_preflight_checks, orb_advert_t *mavlink_log_pub, const char *armedBy);
 
 /**
  * Loop that runs at a lower rate and priority for calibration and parameter tasks.
@@ -383,7 +383,13 @@ int commander_main(int argc, char *argv[])
 	}
 
 	if (!strcmp(argv[1], "arm")) {
-		if (TRANSITION_CHANGED != arm_disarm(true, &mavlink_log_pub, "command line")) {
+		bool force_arming = false;
+
+		if (argc > 2 && !strcmp(argv[2], "-f")) {
+			force_arming = true;
+		}
+
+		if (TRANSITION_CHANGED != arm_disarm(true, !force_arming, &mavlink_log_pub, "command line")) {
 			PX4_ERR("arming failed");
 		}
 
@@ -391,7 +397,7 @@ int commander_main(int argc, char *argv[])
 	}
 
 	if (!strcmp(argv[1], "disarm")) {
-		if (TRANSITION_DENIED == arm_disarm(false, &mavlink_log_pub, "command line")) {
+		if (TRANSITION_DENIED == arm_disarm(false, true, &mavlink_log_pub, "command line")) {
 			PX4_ERR("rejected disarm");
 		}
 
@@ -405,7 +411,7 @@ int commander_main(int argc, char *argv[])
 		/* see if we got a home position */
 		if (status_flags.condition_local_position_valid) {
 
-			if (TRANSITION_DENIED != arm_disarm(true, &mavlink_log_pub, "command line")) {
+			if (TRANSITION_DENIED != arm_disarm(true, true, &mavlink_log_pub, "command line")) {
 				ret = send_vehicle_command(vehicle_command_s::VEHICLE_CMD_NAV_TAKEOFF);
 
 			} else {
@@ -516,7 +522,7 @@ void usage(const char *reason)
 		PX4_INFO("%s", reason);
 	}
 
-	PX4_INFO("usage: commander {start|stop|status|calibrate|check|arm|disarm|takeoff|land|transition|mode}\n");
+	PX4_INFO("usage: commander {start|stop|status|calibrate|check|arm [-f]|disarm|takeoff|land|transition|mode}\n");
 }
 
 void print_status()
@@ -531,7 +537,8 @@ bool shutdown_if_allowed()
 			hrt_elapsed_time(&commander_boot_timestamp));
 }
 
-transition_result_t arm_disarm(bool arm, orb_advert_t *mavlink_log_pub_local, const char *armedBy)
+transition_result_t arm_disarm(bool arm, bool run_preflight_checks, orb_advert_t *mavlink_log_pub_local,
+			       const char *armedBy)
 {
 	transition_result_t arming_res = TRANSITION_NOT_CHANGED;
 
@@ -541,7 +548,7 @@ transition_result_t arm_disarm(bool arm, orb_advert_t *mavlink_log_pub_local, co
 					     safety,
 					     arm ? vehicle_status_s::ARMING_STATE_ARMED : vehicle_status_s::ARMING_STATE_STANDBY,
 					     &armed,
-					     true /* fRunPreArmChecks */,
+					     run_preflight_checks,
 					     mavlink_log_pub_local,
 					     &status_flags,
 					     arm_requirements,
@@ -818,7 +825,7 @@ Commander::handle_command(vehicle_status_s *status_local, const vehicle_command_
 					}
 				}
 
-				transition_result_t arming_res = arm_disarm(cmd_arms, &mavlink_log_pub, "Arm/Disarm component command");
+				transition_result_t arming_res = arm_disarm(cmd_arms, true, &mavlink_log_pub, "Arm/Disarm component command");
 
 				if (arming_res == TRANSITION_DENIED) {
 					cmd_result = vehicle_command_s::VEHICLE_CMD_RESULT_TEMPORARILY_REJECTED;
@@ -1022,7 +1029,7 @@ Commander::handle_command(vehicle_status_s *status_local, const vehicle_command_
 					// switch to AUTO_MISSION and ARM
 					if ((TRANSITION_DENIED != main_state_transition(*status_local, commander_state_s::MAIN_STATE_AUTO_MISSION, status_flags,
 							&internal_state))
-					    && (TRANSITION_DENIED != arm_disarm(true, &mavlink_log_pub, "Mission start command"))) {
+					    && (TRANSITION_DENIED != arm_disarm(true, true, &mavlink_log_pub, "Mission start command"))) {
 
 						cmd_result = vehicle_command_s::VEHICLE_CMD_RESULT_ACCEPTED;
 
@@ -1683,7 +1690,7 @@ Commander::run()
 				}
 
 				if (_auto_disarm_landed.get_state()) {
-					arm_disarm(false, &mavlink_log_pub, "Auto disarm initiated");
+					arm_disarm(false, true, &mavlink_log_pub, "Auto disarm initiated");
 				}
 			}
 
@@ -1691,7 +1698,7 @@ Commander::run()
 			_auto_disarm_killed.set_state_and_update(armed.manual_lockdown, hrt_absolute_time());
 
 			if (_auto_disarm_killed.get_state()) {
-				arm_disarm(false, &mavlink_log_pub, "Kill-switch still engaged, disarming");
+				arm_disarm(false, true, &mavlink_log_pub, "Kill-switch still engaged, disarming");
 			}
 
 		} else {