mtecs: add altitude prefiltering

src/modules/fw_pos_control_l1/mtecs/mTecs.cpp

@@ -59,6 +59,7 @@ mTecs::mTecs() :
 	_controlAltitude(this, "FPA", true),
 	_controlAirSpeed(this, "ACC"),
 	_flightPathAngleLowpass(this, "FPA_LP"),
+	_altitudeLowpass(this, "ALT_LP"),
 	_airspeedLowpass(this, "A_LP"),
 	_airspeedDerivative(this, "AD"),
 	_throttleSp(0.0f),
@@ -93,18 +94,23 @@ int mTecs::updateAltitudeSpeed(float flightPathAngle, float altitude, float alti
 	/* time measurement */
 	updateTimeMeasurement();
 
+	/* Filter altitude */
+	float altitudeFiltered = _altitudeLowpass.update(altitude);
+
+
 	/* calculate flight path angle setpoint from altitude setpoint */
-	float flightPathAngleSp = _controlAltitude.update(altitudeSp - altitude);
+	float flightPathAngleSp = _controlAltitude.update(altitudeSp - altitudeFiltered);
 
 	/* Debug output */
 	if (_counter % 10 == 0) {
 		debug("***");
-		debug("updateAltitudeSpeed: altitudeSp %.4f, altitude %.4f, flightPathAngleSp %.4f", (double)altitudeSp, (double)altitude, (double)flightPathAngleSp);
+		debug("updateAltitudeSpeed: altitudeSp %.4f, altitude %.4f, altitude filtered %.4f, flightPathAngleSp %.4f", (double)altitudeSp, (double)altitude, (double)altitudeFiltered, (double)flightPathAngleSp);
 	}
 
 	/* Write part of the status message */
 	_status.altitudeSp = altitudeSp;
 	_status.altitude = altitude;
+	_status.altitudeFiltered = altitudeFiltered;
 
 
 	/* use flightpath angle setpoint for total energy control */

src/modules/fw_pos_control_l1/mtecs/mTecs.h

@@ -115,6 +115,7 @@ protected:
 
 	/* Other calculation Blocks */
 	control::BlockLowPass _flightPathAngleLowpass;	/**< low pass filter for the flight path angle */
+	control::BlockLowPass _altitudeLowpass;	/**< low pass filter for altitude */
 	control::BlockLowPass _airspeedLowpass;		/**< low pass filter for airspeed */
 	control::BlockDerivative _airspeedDerivative;	/**< airspeed derivative calulation */
 

src/modules/fw_pos_control_l1/mtecs/mTecs_params.c

@@ -174,6 +174,13 @@ PARAM_DEFINE_FLOAT(MT_PIT_MIN, -45.0f);
  */
 PARAM_DEFINE_FLOAT(MT_PIT_MAX, 20.0f);
 
+/**
+ * Lowpass (cutoff freq.) for altitude
+ *
+ * @group mTECS
+ */
+PARAM_DEFINE_FLOAT(MT_ALT_LP, 1.0f);
+
 /**
  * Lowpass (cutoff freq.) for the flight path angle
  *

src/modules/sdlog2/sdlog2.c

@@ -1595,6 +1595,7 @@ int sdlog2_thread_main(int argc, char *argv[])
 			log_msg.msg_type = LOG_TECS_MSG;
 			log_msg.body.log_TECS.altitudeSp = buf.tecs_status.altitudeSp;
 			log_msg.body.log_TECS.altitude = buf.tecs_status.altitude;
+			log_msg.body.log_TECS.altitudeFiltered = buf.tecs_status.altitudeFiltered;
 			log_msg.body.log_TECS.flightPathAngleSp = buf.tecs_status.flightPathAngleSp;
 			log_msg.body.log_TECS.flightPathAngle = buf.tecs_status.flightPathAngle;
 			log_msg.body.log_TECS.flightPathAngleFiltered = buf.tecs_status.flightPathAngleFiltered;

src/modules/sdlog2/sdlog2_messages.h

@@ -334,6 +334,7 @@ struct log_GS1B_s {
 struct log_TECS_s {
 	float altitudeSp;
 	float altitude;
+	float altitudeFiltered;
 	float flightPathAngleSp;
 	float flightPathAngle;
 	float flightPathAngleFiltered;
@@ -454,7 +455,7 @@ static const struct log_format_s log_formats[] = {
 	LOG_FORMAT(GS0B, "BBBBBBBBBBBBBBBB",	"s0,s1,s2,s3,s4,s5,s6,s7,s8,s9,s10,s11,s12,s13,s14,s15"),
 	LOG_FORMAT(GS1A, "BBBBBBBBBBBBBBBB",	"s0,s1,s2,s3,s4,s5,s6,s7,s8,s9,s10,s11,s12,s13,s14,s15"),
 	LOG_FORMAT(GS1B, "BBBBBBBBBBBBBBBB",	"s0,s1,s2,s3,s4,s5,s6,s7,s8,s9,s10,s11,s12,s13,s14,s15"),
-	LOG_FORMAT(TECS, "ffffffffffffffB",	"AltSP,Alt,FSP,F,FF,AsSP,As,AsF,AsDSP,AsD,TERSP,TER,EDRSP,EDR,M"),
+	LOG_FORMAT(TECS, "fffffffffffffffB",	"ASP,A,AF,FSP,F,FF,AsSP,As,AsF,AsDSP,AsD,TERSP,TER,EDRSP,EDR,M"),
 	LOG_FORMAT(WIND, "ffff",	"X,Y,CovX,CovY"),
 
 	/* system-level messages, ID >= 0x80 */

src/modules/uORB/topics/tecs_status.h

@@ -66,6 +66,7 @@ struct tecs_status_s {
 
 	float altitudeSp;
 	float altitude;
+	float altitudeFiltered;
 	float flightPathAngleSp;
 	float flightPathAngle;
 	float flightPathAngleFiltered;