simulation: SITL outputs from 0..1

Instead of sending actuator controls from -1..1 for SITL, we should send
0..1 like we already do for HIL. This will enable negative thrust in the
future, e.g. for pusher props that spin backwards, or for vehicles with
variable pitch propellers.

Tools/jMAVSim

@@ -1 +1 @@
-Subproject commit 4e49f05e57d9f7555259843b8081ec7e607ef49e
+Subproject commit fec27e3ce567c794b5c364dc9856b55431130181

Tools/sitl_gazebo

@@ -1 +1 @@
-Subproject commit 380fce8b478361b086cef18597f885002975e701
+Subproject commit b9ed67482e940124133a281da963a8239e8b574c

src/modules/mavlink/mavlink_messages.cpp

@@ -2172,11 +2172,11 @@ protected:
 				for (unsigned i = 0; i < 8; i++) {
 					if (act.output[i] > PWM_DEFAULT_MIN / 2) {
 						if (i < n) {
-							/* scale PWM out 900..2100 us to 0..1 for rotors */
+							/* scale PWM out PWM_DEFAULT_MIN..PWM_DEFAULT_MAX us to -1..1 for rotors */
 							out[i] = (act.output[i] - PWM_DEFAULT_MIN) / (PWM_DEFAULT_MAX - PWM_DEFAULT_MIN);
 
 						} else {
-							/* scale PWM out 900..2100 us to -1..1 for other channels */
+							/* scale PWM out PWM_DEFAULT_MIN..PWM_DEFAULT_MAX us to -1..1 for other channels */
 							out[i] = (act.output[i] - pwm_center) / ((PWM_DEFAULT_MAX - PWM_DEFAULT_MIN) / 2);
 						}
 
@@ -2192,11 +2192,11 @@ protected:
 				for (unsigned i = 0; i < 8; i++) {
 					if (act.output[i] > PWM_DEFAULT_MIN / 2) {
 						if (i != 3) {
-							/* scale PWM out 900..2100 us to -1..1 for normal channels */
+							/* scale PWM out PWM_DEFAULT_MIN..PWM_DEFAULT_MAX us to -1..1 for normal channels */
 							out[i] = (act.output[i] - pwm_center) / ((PWM_DEFAULT_MAX - PWM_DEFAULT_MIN) / 2);
 
 						} else {
-							/* scale PWM out 900..2100 us to 0..1 for throttle */
+							/* scale PWM out PWM_DEFAULT_MIN..PWM_DEFAULT_MAX us to 0..1 for throttle */
 							out[i] = (act.output[i] - PWM_DEFAULT_MIN) / (PWM_DEFAULT_MAX - PWM_DEFAULT_MIN);
 						}
 

src/modules/simulator/simulator.h

@@ -241,7 +241,8 @@ private:
 		_flow_pub(nullptr),
 		_dist_pub(nullptr),
 		_battery_pub(nullptr),
-		_initialized(false)
+		_initialized(false),
+		_system_type(0)
 #ifndef __PX4_QURT
 		,
 		_rc_channels_pub(nullptr),
@@ -257,6 +258,11 @@ private:
 		_vehicle_status{}
 #endif
 	{
+		// We need to know the type for the correct mapping from
+		// actuator controls to the hil actuator message.
+		param_t param_system_type = param_find("MAV_TYPE");
+		param_get(param_system_type, &_system_type);
+
 		for (unsigned i = 0; i < (sizeof(_actuator_outputs_sub) / sizeof(_actuator_outputs_sub[0])); i++)
 		{
 			_actuator_outputs_sub[i] = -1;
@@ -299,6 +305,9 @@ private:
 	// Lib used to do the battery calculations.
 	Battery _battery;
 
+	// For param MAV_TYPE
+	int32_t _system_type;
+
 	// class methods
 	int publish_sensor_topics(mavlink_hil_sensor_t *imu);
 	int publish_flow_topic(mavlink_hil_optical_flow_t *flow);

src/modules/simulator/simulator_mavlink.cpp

@@ -78,26 +78,93 @@ const unsigned mode_flag_custom = 1;
 
 using namespace simulator;
 
-void Simulator::pack_actuator_message(mavlink_hil_actuator_controls_t &actuator_msg, unsigned index)
+void Simulator::pack_actuator_message(mavlink_hil_actuator_controls_t &msg, unsigned index)
 {
-	actuator_msg.time_usec = hrt_absolute_time();
+	msg.time_usec = hrt_absolute_time();
 
 	bool armed = (_vehicle_status.arming_state == vehicle_status_s::ARMING_STATE_ARMED);
 
 	const float pwm_center = (PWM_DEFAULT_MAX + PWM_DEFAULT_MIN) / 2;
 
-	for (unsigned i = 0; i < MAVLINK_MSG_HIL_ACTUATOR_CONTROLS_FIELD_CONTROLS_LEN; i++) {
-		// scale PWM out 900..2100 us to -1..1 */
-		actuator_msg.controls[i] = (_actuators[index].output[i] - pwm_center) / ((PWM_DEFAULT_MAX - PWM_DEFAULT_MIN) / 2);
+	/* scale outputs depending on system type */
+	if (_system_type == MAV_TYPE_QUADROTOR ||
+	    _system_type == MAV_TYPE_HEXAROTOR ||
+	    _system_type == MAV_TYPE_OCTOROTOR ||
+	    _system_type == MAV_TYPE_VTOL_DUOROTOR ||
+	    _system_type == MAV_TYPE_VTOL_QUADROTOR ||
+	    _system_type == MAV_TYPE_VTOL_RESERVED2) {
 
-		if (!PX4_ISFINITE(actuator_msg.controls[i])) {
-			actuator_msg.controls[i] = -1.0f;
+		/* multirotors: set number of rotor outputs depending on type */
+
+		unsigned n;
+
+		switch (_system_type) {
+		case MAV_TYPE_QUADROTOR:
+			n = 4;
+			break;
+
+		case MAV_TYPE_HEXAROTOR:
+			n = 6;
+			break;
+
+		case MAV_TYPE_VTOL_DUOROTOR:
+			n = 2;
+			break;
+
+		case MAV_TYPE_VTOL_QUADROTOR:
+			n = 4;
+			break;
+
+		case MAV_TYPE_VTOL_RESERVED2:
+			n = 8;
+			break;
+
+		default:
+			n = 8;
+			break;
+		}
+
+		for (unsigned i = 0; i < 16; i++) {
+			if (_actuators[index].output[i] > PWM_DEFAULT_MIN / 2) {
+				if (i < n) {
+					/* scale PWM out PWM_DEFAULT_MIN..PWM_DEFAULT_MAX us to 0..1 for rotors */
+					msg.controls[i] = (_actuators[index].output[i] - PWM_DEFAULT_MIN) / (PWM_DEFAULT_MAX - PWM_DEFAULT_MIN);
+
+				} else {
+					/* scale PWM out PWM_DEFAULT_MIN..PWM_DEFAULT_MAX us to -1..1 for other channels */
+					msg.controls[i] = (_actuators[index].output[i] - pwm_center) / ((PWM_DEFAULT_MAX - PWM_DEFAULT_MIN) / 2);
+				}
+
+			} else {
+				/* send 0 when disarmed and for disabled channels */
+				msg.controls[i] = 0.0f;
+			}
+		}
+
+	} else {
+		/* fixed wing: scale throttle to 0..1 and other channels to -1..1 */
+
+		for (unsigned i = 0; i < 16; i++) {
+			if (_actuators[index].output[i] > PWM_DEFAULT_MIN / 2) {
+				if (i != 3) {
+					/* scale PWM out PWM_DEFAULT_MIN..PWM_DEFAULT_MAX us to -1..1 for normal channels */
+					msg.controls[i] = (_actuators[index].output[i] - pwm_center) / ((PWM_DEFAULT_MAX - PWM_DEFAULT_MIN) / 2);
+
+				} else {
+					/* scale PWM out PWM_DEFAULT_MIN..PWM_DEFAULT_MAX us to 0..1 for throttle */
+					msg.controls[i] = (_actuators[index].output[i] - PWM_DEFAULT_MIN) / (PWM_DEFAULT_MAX - PWM_DEFAULT_MIN);
+				}
+
+			} else {
+				/* set 0 for disabled channels */
+				msg.controls[i] = 0.0f;
+			}
 		}
 	}
 
-	actuator_msg.mode = mode_flag_custom;
-	actuator_msg.mode |= (armed) ? mode_flag_armed : 0;
-	actuator_msg.flags = 0;
+	msg.mode = mode_flag_custom;
+	msg.mode |= (armed) ? mode_flag_armed : 0;
+	msg.flags = 0;
 }
 
 void Simulator::send_controls()