Track raw battery voltage and filtered battery voltage separately. Estimate remaining battery as min(voltage_estimate, discharged_estimate). Battery voltage LPF time increased.

src/modules/commander/commander.cpp

@@ -107,14 +107,9 @@ static const int ERROR = -1;
 
 extern struct system_load_s system_load;
 
-#define LOW_VOLTAGE_BATTERY_HYSTERESIS_TIME_MS 1000.0f
-#define CRITICAL_VOLTAGE_BATTERY_HYSTERESIS_TIME_MS 100.0f
-
 /* Decouple update interval and hysteris counters, all depends on intervals */
 #define COMMANDER_MONITORING_INTERVAL 50000
 #define COMMANDER_MONITORING_LOOPSPERMSEC (1/(COMMANDER_MONITORING_INTERVAL/1000.0f))
-#define LOW_VOLTAGE_BATTERY_COUNTER_LIMIT (LOW_VOLTAGE_BATTERY_HYSTERESIS_TIME_MS*COMMANDER_MONITORING_LOOPSPERMSEC)
-#define CRITICAL_VOLTAGE_BATTERY_COUNTER_LIMIT (CRITICAL_VOLTAGE_BATTERY_HYSTERESIS_TIME_MS*COMMANDER_MONITORING_LOOPSPERMSEC)
 
 #define MAVLINK_OPEN_INTERVAL 50000
 
@@ -666,8 +661,6 @@ int commander_thread_main(int argc, char *argv[])
 
 	/* Start monitoring loop */
 	unsigned counter = 0;
-	unsigned low_voltage_counter = 0;
-	unsigned critical_voltage_counter = 0;
 	unsigned stick_off_counter = 0;
 	unsigned stick_on_counter = 0;
 
@@ -745,7 +738,6 @@ int commander_thread_main(int argc, char *argv[])
 	int battery_sub = orb_subscribe(ORB_ID(battery_status));
 	struct battery_status_s battery;
 	memset(&battery, 0, sizeof(battery));
-	battery.voltage_v = 0.0f;
 
 	/* Subscribe to subsystem info topic */
 	int subsys_sub = orb_subscribe(ORB_ID(subsystem_info));
@@ -890,15 +882,12 @@ int commander_thread_main(int argc, char *argv[])
 
 		if (updated) {
 			orb_copy(ORB_ID(battery_status), battery_sub, &battery);
-
-			// warnx("bat v: %2.2f", battery.voltage_v);
-
-			/* only consider battery voltage if system has been running 2s and battery voltage is higher than 4V */
-			if (hrt_absolute_time() > start_time + 2000000 && battery.voltage_v > 4.0f) {
-				status.battery_voltage = battery.voltage_v;
+			/* only consider battery voltage if system has been running 2s and battery voltage is valid */
+			if (hrt_absolute_time() > start_time + 2000000 && battery.voltage_filtered_v > 0.0f) {
+				status.battery_voltage = battery.voltage_filtered_v;
 				status.battery_current = battery.current_a;
 				status.condition_battery_voltage_valid = true;
-				status.battery_remaining = battery_remaining_estimate_voltage(battery.voltage_v, battery.discharged_mah);
+				status.battery_remaining = battery_remaining_estimate_voltage(battery.voltage_filtered_v, battery.discharged_mah);
 			}
 		}
 
@@ -951,46 +940,29 @@ int commander_thread_main(int argc, char *argv[])
 			//on_usb_power = (stat("/dev/ttyACM0", &statbuf) == 0);
 		}
 
-		// XXX remove later
-		//warnx("bat remaining: %2.2f", status.battery_remaining);
-
 		/* if battery voltage is getting lower, warn using buzzer, etc. */
 		if (status.condition_battery_voltage_valid && status.battery_remaining < 0.25f && !low_battery_voltage_actions_done) {
-			//TODO: add filter, or call emergency after n measurements < VOLTAGE_BATTERY_MINIMAL_MILLIVOLTS
-			if (low_voltage_counter > LOW_VOLTAGE_BATTERY_COUNTER_LIMIT) {
-				low_battery_voltage_actions_done = true;
-				mavlink_log_critical(mavlink_fd, "#audio: WARNING: LOW BATTERY");
-				status.battery_warning = VEHICLE_BATTERY_WARNING_LOW;
-				status_changed = true;
-				battery_tune_played = false;
-			}
-
-			low_voltage_counter++;
+			low_battery_voltage_actions_done = true;
+			mavlink_log_critical(mavlink_fd, "#audio: WARNING: LOW BATTERY");
+			status.battery_warning = VEHICLE_BATTERY_WARNING_LOW;
+			status_changed = true;
+			battery_tune_played = false;
 
 		} else if (status.condition_battery_voltage_valid && status.battery_remaining < 0.1f && !critical_battery_voltage_actions_done && low_battery_voltage_actions_done) {
 			/* critical battery voltage, this is rather an emergency, change state machine */
-			if (critical_voltage_counter > CRITICAL_VOLTAGE_BATTERY_COUNTER_LIMIT) {
-				critical_battery_voltage_actions_done = true;
-				mavlink_log_critical(mavlink_fd, "#audio: EMERGENCY: CRITICAL BATTERY");
-				status.battery_warning = VEHICLE_BATTERY_WARNING_CRITICAL;
-				battery_tune_played = false;
-
-				if (armed.armed) {
-					arming_state_transition(&status, &safety, &control_mode, ARMING_STATE_ARMED_ERROR, &armed);
+			critical_battery_voltage_actions_done = true;
+			mavlink_log_critical(mavlink_fd, "#audio: EMERGENCY: CRITICAL BATTERY");
+			status.battery_warning = VEHICLE_BATTERY_WARNING_CRITICAL;
+			battery_tune_played = false;
 
-				} else {
-					arming_state_transition(&status, &safety, &control_mode, ARMING_STATE_STANDBY_ERROR, &armed);
-				}
+			if (armed.armed) {
+				arming_state_transition(&status, &safety, &control_mode, ARMING_STATE_ARMED_ERROR, &armed);
 
-				status_changed = true;
+			} else {
+				arming_state_transition(&status, &safety, &control_mode, ARMING_STATE_STANDBY_ERROR, &armed);
 			}
 
-			critical_voltage_counter++;
-
-		} else {
-
-			low_voltage_counter = 0;
-			critical_voltage_counter = 0;
+			status_changed = true;
 		}
 
 		/* End battery voltage check */

src/modules/commander/commander_helper.cpp

@@ -44,6 +44,7 @@
 #include <stdint.h>
 #include <stdbool.h>
 #include <fcntl.h>
+#include <math.h>
 
 #include <uORB/uORB.h>
 #include <uORB/topics/vehicle_status.h>
@@ -282,12 +283,15 @@ float battery_remaining_estimate_voltage(float voltage, float discharged)
 
 	counter++;
 
+	/* remaining charge estimate based on voltage */
+	float remaining_voltage = (voltage - bat_n_cells * bat_v_empty) / (bat_n_cells * (bat_v_full - bat_v_empty));
+
 	if (bat_capacity > 0.0f) {
-		/* if battery capacity is known, use it to estimate remaining charge */
-		ret = 1.0f - discharged / bat_capacity;
+		/* if battery capacity is known, use discharged current for estimate, but don't show more than voltage estimate */
+		ret = fminf(remaining_voltage, 1.0f - discharged / bat_capacity);
 	} else {
 		/* else use voltage */
-		ret = (voltage - bat_n_cells * bat_v_empty) / (bat_n_cells * (bat_v_full - bat_v_empty));
+		ret = remaining_voltage;
 	}
 
 	/* limit to sane values */

src/modules/sdlog2/sdlog2.c

@@ -1264,6 +1264,7 @@ int sdlog2_thread_main(int argc, char *argv[])
 				orb_copy(ORB_ID(battery_status), subs.battery_sub, &buf.battery);
 				log_msg.msg_type = LOG_BATT_MSG;
 				log_msg.body.log_BATT.voltage = buf.battery.voltage_v;
+				log_msg.body.log_BATT.voltage_filtered = buf.battery.voltage_filtered_v;
 				log_msg.body.log_BATT.current = buf.battery.current_a;
 				log_msg.body.log_BATT.discharged = buf.battery.discharged_mah;
 				LOGBUFFER_WRITE_AND_COUNT(BATT);

src/modules/sdlog2/sdlog2_messages.h

@@ -249,6 +249,7 @@ struct log_GVSP_s {
 #define LOG_BATT_MSG 20
 struct log_BATT_s {
 	float voltage;
+	float voltage_filtered;
 	float current;
 	float discharged;
 };
@@ -296,7 +297,7 @@ static const struct log_format_s log_formats[] = {
 	LOG_FORMAT(GPSP, "BLLfffbBffff", "AltRel,Lat,Lon,Alt,Yaw,LoiterR,LoiterDir,NavCmd,P1,P2,P3,P4"),
 	LOG_FORMAT(ESC, "HBBBHHHHHHfH", "Counter,NumESC,Conn,N,Ver,Adr,Volt,Amp,RPM,Temp,SetP,SetPRAW"),
 	LOG_FORMAT(GVSP, "fff", "VX,VY,VZ"),
-	LOG_FORMAT(BATT, "fff", "V,C,Discharged"),
+	LOG_FORMAT(BATT, "ffff", "V,VFilt,C,Discharged"),
 	/* system-level messages, ID >= 0x80 */
 	// FMT: don't write format of format message, it's useless
 	LOG_FORMAT(TIME, "Q", "StartTime"),

src/modules/sensors/sensors.cpp

@@ -125,9 +125,8 @@
 #define ADC_AIRSPEED_VOLTAGE_CHANNEL	15
 #endif
 
-#define BAT_VOL_INITIAL 0.f
-#define BAT_VOL_LOWPASS 0.01f
-#define VOLTAGE_BATTERY_IGNORE_THRESHOLD_VOLTS 3.5f
+#define BATT_V_LOWPASS 0.001f
+#define BATT_V_IGNORE_THRESHOLD 3.5f
 
 /**
  * HACK - true temperature is much less than indicated temperature in baro,
@@ -1173,32 +1172,40 @@ Sensors::adc_poll(struct sensor_combined_s &raw)
 					/* Voltage in volts */
 					float voltage = (buf_adc[i].am_data * _parameters.battery_voltage_scaling);
 
-					if (voltage > VOLTAGE_BATTERY_IGNORE_THRESHOLD_VOLTS) {
+					if (voltage > BATT_V_IGNORE_THRESHOLD) {
+						_battery_status.voltage_v = voltage;
 						/* one-time initialization of low-pass value to avoid long init delays */
-						if (_battery_status.voltage_v < VOLTAGE_BATTERY_IGNORE_THRESHOLD_VOLTS) {
-							_battery_status.voltage_v = voltage;
+						if (_battery_status.voltage_filtered_v < BATT_V_IGNORE_THRESHOLD) {
+							_battery_status.voltage_filtered_v = voltage;
 						}
 
 						_battery_status.timestamp = t;
-						_battery_status.voltage_v += (voltage - _battery_status.voltage_v) * BAT_VOL_LOWPASS;
+						_battery_status.voltage_filtered_v += (voltage - _battery_status.voltage_filtered_v) * BATT_V_LOWPASS;
 
 					} else {
 						/* mark status as invalid */
-						_battery_status.timestamp = 0;
+						_battery_status.voltage_v = -1.0f;
+						_battery_status.voltage_filtered_v = -1.0f;
 					}
 
 				} else if (ADC_BATTERY_CURRENT_CHANNEL == buf_adc[i].am_channel) {
 					/* handle current only if voltage is valid */
-					if (_battery_status.timestamp != 0) {
+					if (_battery_status.voltage_v > 0.0f) {
 						float current = (buf_adc[i].am_data * _parameters.battery_current_scaling);
-						_battery_status.timestamp = t;
-						_battery_status.current_a = current;
-						if (_battery_current_timestamp != 0) {
-							_battery_discharged += current * (t - _battery_current_timestamp);
-							_battery_status.discharged_mah = ((float) _battery_discharged) / 3600000.0f;
+						/* check measured current value */
+						if (current >= 0.0f) {
+							_battery_status.timestamp = t;
+							_battery_status.current_a = current;
+							if (_battery_current_timestamp != 0) {
+								/* initialize discharged value */
+								if (_battery_status.discharged_mah < 0.0f)
+									_battery_status.discharged_mah = 0.0f;
+								_battery_discharged += current * (t - _battery_current_timestamp);
+								_battery_status.discharged_mah = ((float) _battery_discharged) / 3600000.0f;
+							}
 						}
-						_battery_current_timestamp = t;
 					}
+					_battery_current_timestamp = t;
 
 				} else if (ADC_AIRSPEED_VOLTAGE_CHANNEL == buf_adc[i].am_channel) {
 
@@ -1229,7 +1236,7 @@ Sensors::adc_poll(struct sensor_combined_s &raw)
 				}
 			}
 			_last_adc = t;
-			if (_battery_status.timestamp != 0) {
+			if (_battery_status.voltage_v > 0.0f) {
 				/* announce the battery status if needed, just publish else */
 				if (_battery_pub > 0) {
 					orb_publish(ORB_ID(battery_status), _battery_pub, &_battery_status);
@@ -1512,7 +1519,10 @@ Sensors::task_main()
 	raw.adc_voltage_v[3] = 0.0f;
 
 	memset(&_battery_status, 0, sizeof(_battery_status));
-	_battery_status.voltage_v = BAT_VOL_INITIAL;
+	_battery_status.voltage_v = 0.0f;
+	_battery_status.voltage_filtered_v = 0.0f;
+	_battery_status.current_a = -1.0f;
+	_battery_status.discharged_mah = -1.0f;
 
 	/* get a set of initial values */
 	accel_poll(raw);

src/modules/uORB/topics/battery_status.h

@@ -53,7 +53,8 @@
  */
 struct battery_status_s {
 	uint64_t	timestamp;		/**< microseconds since system boot, needed to integrate */
-	float   	voltage_v;		/**< Battery voltage in volts, filtered           	 */
+	float   	voltage_v;		/**< Battery voltage in volts, 0 if unknown           	 */
+	float   	voltage_filtered_v;		/**< Battery voltage in volts, filtered, 0 if unknown  	 */
 	float		current_a;		/**< Battery current in amperes, -1 if unknown */
 	float		discharged_mah;		/**< Discharged amount in mAh, -1 if unknown	 */
 };