'signal_lost' flag added to manual_control_setpoint and rc_channels topics to indicate signal loss immediately

src/modules/commander/commander.cpp

@@ -118,8 +118,7 @@ extern struct system_load_s system_load;
 #define STICK_ON_OFF_COUNTER_LIMIT (STICK_ON_OFF_HYSTERESIS_TIME_MS*COMMANDER_MONITORING_LOOPSPERMSEC)
 
 #define POSITION_TIMEOUT 1000000 /**< consider the local or global position estimate invalid after 1s */
-#define RC_TIMEOUT 100000
-#define RC_TIMEOUT_HIL 500000
+#define RC_TIMEOUT 500000
 #define DIFFPRESS_TIMEOUT 2000000
 
 #define PRINT_INTERVAL	5000000
@@ -1109,16 +1108,8 @@ int commander_thread_main(int argc, char *argv[])
 			}
 		}
 
-
-		/*
-		 * XXX workaround:
-		 * Prevent RC loss in HIL when sensors.cpp is only publishing sp_man at a low rate (e.g. 30Hz)
-		 * which can trigger RC loss if the computer/simulator lags.
-		 */
-		uint64_t rc_timeout = status.hil_state == HIL_STATE_ON ? RC_TIMEOUT_HIL : RC_TIMEOUT;
-
 		/* start RC input check */
-		if (!status.rc_input_blocked && sp_man.timestamp != 0 && hrt_absolute_time() < sp_man.timestamp + rc_timeout) {
+		if (!status.rc_input_blocked && !sp_man.signal_lost && hrt_absolute_time() < sp_man.timestamp + RC_TIMEOUT) {
 			/* handle the case where RC signal was regained */
 			if (!status.rc_signal_found_once) {
 				status.rc_signal_found_once = true;

src/modules/sensors/sensors.cpp

@@ -474,6 +474,7 @@ Sensors::Sensors() :
 	_battery_discharged(0),
 	_battery_current_timestamp(0)
 {
+	memset(&_rc, 0, sizeof(_rc));
 
 	/* basic r/c parameters */
 	for (unsigned i = 0; i < _rc_max_chan_count; i++) {
@@ -1283,12 +1284,6 @@ Sensors::rc_poll()
 	if (rc_updated) {
 		/* read low-level values from FMU or IO RC inputs (PPM, Spektrum, S.Bus) */
 		struct rc_input_values	rc_input;
-
-		orb_copy(ORB_ID(input_rc), _rc_sub, &rc_input);
-
-		if (rc_input.rc_lost)
-			return;
-
 		struct manual_control_setpoint_s manual_control;
 		struct actuator_controls_s actuator_group_3;
 
@@ -1311,19 +1306,28 @@ Sensors::rc_poll()
 		manual_control.aux4 = NAN;
 		manual_control.aux5 = NAN;
 
-		/* require at least four channels to consider the signal valid */
-		if (rc_input.channel_count < 4)
-			return;
+		manual_control.signal_lost = true;
+
+		orb_copy(ORB_ID(input_rc), _rc_sub, &rc_input);
 
-		/* failsafe check */
+		/* detect RC signal loss */
+		/* check flags and require at least four channels to consider the signal valid */
+		if (!(rc_input.rc_lost || rc_input.rc_failsafe || rc_input.channel_count < 4)) {
+			/* signal looks good */
+			manual_control.signal_lost = false;
+
+			/* check throttle failsafe */
 			if (_parameters.rc_fs_ch != 0) {
 				if (_parameters.rc_fs_mode == 0) {
-				if (rc_input.values[_parameters.rc_fs_ch - 1] < _parameters.rc_fs_thr)
-					return;
+					if (rc_input.values[_parameters.rc_fs_ch - 1] < _parameters.rc_fs_thr) {
+						manual_control.signal_lost = true;
+					}
 
 				} else if (_parameters.rc_fs_mode == 1) {
-				if (rc_input.values[_parameters.rc_fs_ch - 1] > _parameters.rc_fs_thr)
-					return;
+					if (rc_input.values[_parameters.rc_fs_ch - 1] > _parameters.rc_fs_thr) {
+						manual_control.signal_lost = true;
+					}
+				}
 			}
 		}
 
@@ -1332,10 +1336,7 @@ Sensors::rc_poll()
 		if (channel_limit > _rc_max_chan_count)
 			channel_limit = _rc_max_chan_count;
 
-		/* we are accepting this message */
-		_rc_last_valid = rc_input.timestamp_last_signal;
-
-		/* Read out values from raw message */
+		/* read out and scale values from raw message even if signal is invalid */
 		for (unsigned int i = 0; i < channel_limit; i++) {
 
 			/*
@@ -1382,9 +1383,19 @@ Sensors::rc_poll()
 		}
 
 		_rc.chan_count = rc_input.channel_count;
-		_rc.timestamp = rc_input.timestamp_last_signal;
+		_rc.rssi = rc_input.rssi;
+		_rc.signal_lost = manual_control.signal_lost;
+
+		if (!manual_control.signal_lost) {
+			_rc_last_valid = rc_input.timestamp_last_signal;
+		}
 
-		manual_control.timestamp = rc_input.timestamp_last_signal;
+		_rc.timestamp = _rc_last_valid;
+
+		manual_control.timestamp = _rc_last_valid;
+
+		if (!manual_control.signal_lost) {
+			/* fill values in manual_control_setpoint topic only if signal is valid */
 
 			/* roll input - rolling right is stick-wise and rotation-wise positive */
 			manual_control.roll = limit_minus_one_to_one(_rc.chan[_rc.function[ROLL]].scaled);
@@ -1445,9 +1456,9 @@ Sensors::rc_poll()
 				manual_control.return_switch = limit_minus_one_to_one(_rc.chan[_rc.function[RETURN]].scaled);
 			}
 
-//		if (_rc.function[OFFBOARD_MODE] >= 0) {
-//			manual_control.auto_offboard_input_switch = limit_minus_one_to_one(_rc.chan[_rc.function[OFFBOARD_MODE]].scaled);
-//		}
+	//		if (_rc.function[OFFBOARD_MODE] >= 0) {
+	//			manual_control.auto_offboard_input_switch = limit_minus_one_to_one(_rc.chan[_rc.function[OFFBOARD_MODE]].scaled);
+	//		}
 
 			/* aux functions, only assign if valid mapping is present */
 			if (_rc.function[AUX_1] >= 0) {
@@ -1480,7 +1491,16 @@ Sensors::rc_poll()
 			actuator_group_3.control[6] = manual_control.aux2;
 			actuator_group_3.control[7] = manual_control.aux3;
 
-		/* check if ready for publishing */
+			/* publish actuator_controls_3 topic only if control signal is valid */
+			if (_actuator_group_3_pub > 0) {
+				orb_publish(ORB_ID(actuator_controls_3), _actuator_group_3_pub, &actuator_group_3);
+
+			} else {
+				_actuator_group_3_pub = orb_advertise(ORB_ID(actuator_controls_3), &actuator_group_3);
+			}
+		}
+
+		/* publish rc_channels topic even if signal is invalid, for debug */
 		if (_rc_pub > 0) {
 			orb_publish(ORB_ID(rc_channels), _rc_pub, &_rc);
 
@@ -1489,21 +1509,13 @@ Sensors::rc_poll()
 			_rc_pub = orb_advertise(ORB_ID(rc_channels), &_rc);
 		}
 
-		/* check if ready for publishing */
+		/* publish manual_control_setpoint topic even if signal is not valid to update 'signal_lost' flag */
 		if (_manual_control_pub > 0) {
 			orb_publish(ORB_ID(manual_control_setpoint), _manual_control_pub, &manual_control);
 
 		} else {
 			_manual_control_pub = orb_advertise(ORB_ID(manual_control_setpoint), &manual_control);
 		}
-
-		/* check if ready for publishing */
-		if (_actuator_group_3_pub > 0) {
-			orb_publish(ORB_ID(actuator_controls_3), _actuator_group_3_pub, &actuator_group_3);
-
-		} else {
-			_actuator_group_3_pub = orb_advertise(ORB_ID(actuator_controls_3), &actuator_group_3);
-		}
 	}
 
 }

src/modules/uORB/topics/manual_control_setpoint.h

@@ -51,6 +51,8 @@
 struct manual_control_setpoint_s {
 	uint64_t timestamp;
 
+	bool signal_lost;		/**< control signal lost, should be checked together with topic timeout */
+
 	float roll;			 	/**< ailerons roll / roll rate input */
 	float pitch;				/**< elevator / pitch / pitch rate */
 	float yaw;				/**< rudder / yaw rate / yaw */

src/modules/uORB/topics/rc_channels.h

@@ -94,6 +94,7 @@ struct rc_channels_s {
 	char function_name[RC_CHANNELS_FUNCTION_MAX][20];
 	int8_t function[RC_CHANNELS_FUNCTION_MAX];
 	uint8_t rssi;                       /**< Overall receive signal strength */
+	bool signal_lost;		/**< control signal lost, should be checked together with topic timeout */
 }; /**< radio control channels. */
 
 /**