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author | Lorenz Meier <lm@inf.ethz.ch> | 2013-01-21 23:45:16 +0100 |
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committer | Lorenz Meier <lm@inf.ethz.ch> | 2013-01-21 23:45:16 +0100 |
commit | 2ebb1812f1eea47f06e79650242416493ce279b9 (patch) | |
tree | 1957033e730cf778fa85f90036e9f963c8e2d6a6 /apps/sensors | |
parent | 48e497e4069a2f8773d90f2d1887967a81e487d8 (diff) | |
download | px4-firmware-2ebb1812f1eea47f06e79650242416493ce279b9.tar.gz px4-firmware-2ebb1812f1eea47f06e79650242416493ce279b9.tar.bz2 px4-firmware-2ebb1812f1eea47f06e79650242416493ce279b9.zip |
Implemented airspeed measurement. Untested
Diffstat (limited to 'apps/sensors')
-rw-r--r-- | apps/sensors/sensors.cpp | 101 |
1 files changed, 75 insertions, 26 deletions
diff --git a/apps/sensors/sensors.cpp b/apps/sensors/sensors.cpp index 2697cf3d9..d8d200ea9 100644 --- a/apps/sensors/sensors.cpp +++ b/apps/sensors/sensors.cpp @@ -67,6 +67,7 @@ #include <systemlib/perf_counter.h> #include <systemlib/ppm_decode.h> +#include <systemlib/airspeed.h> #include <uORB/uORB.h> #include <uORB/topics/sensor_combined.h> @@ -75,6 +76,7 @@ #include <uORB/topics/vehicle_status.h> #include <uORB/topics/parameter_update.h> #include <uORB/topics/battery_status.h> +#include <uORB/topics/differential_pressure.h> #define GYRO_HEALTH_COUNTER_LIMIT_ERROR 20 /* 40 ms downtime at 500 Hz update rate */ #define ACC_HEALTH_COUNTER_LIMIT_ERROR 20 /* 40 ms downtime at 500 Hz update rate */ @@ -88,9 +90,10 @@ #define BARO_HEALTH_COUNTER_LIMIT_OK 5 #define ADC_HEALTH_COUNTER_LIMIT_OK 5 -#define ADC_BATTERY_VOLTAGE_CHANNEL 10 +#define ADC_BATTERY_VOLTAGE_CHANNEL 10 +#define ADC_AIRSPEED_VOLTAGE_CHANNEL 11 -#define BAT_VOL_INITIAL 12.f +#define BAT_VOL_INITIAL 0.f #define BAT_VOL_LOWPASS_1 0.99f #define BAT_VOL_LOWPASS_2 0.01f #define VOLTAGE_BATTERY_IGNORE_THRESHOLD_VOLTS 3.5f @@ -161,11 +164,14 @@ private: orb_advert_t _manual_control_pub; /**< manual control signal topic */ orb_advert_t _rc_pub; /**< raw r/c control topic */ orb_advert_t _battery_pub; /**< battery status */ + orb_advert_t _airspeed_pub; /**< airspeed */ perf_counter_t _loop_perf; /**< loop performance counter */ struct rc_channels_s _rc; /**< r/c channel data */ struct battery_status_s _battery_status; /**< battery status */ + struct baro_report _barometer; /**< barometer data */ + struct differential_pressure_s _differential_pressure; struct { float min[_rc_max_chan_count]; @@ -389,6 +395,7 @@ Sensors::Sensors() : _manual_control_pub(-1), _rc_pub(-1), _battery_pub(-1), + _airspeed_pub(-1), /* performance counters */ _loop_perf(perf_alloc(PC_ELAPSED, "sensor task update")) @@ -861,13 +868,12 @@ Sensors::baro_poll(struct sensor_combined_s &raw) orb_check(_baro_sub, &baro_updated); if (baro_updated) { - struct baro_report baro_report; - orb_copy(ORB_ID(sensor_baro), _baro_sub, &baro_report); + orb_copy(ORB_ID(sensor_baro), _baro_sub, &_barometer); - raw.baro_pres_mbar = baro_report.pressure; // Pressure in mbar - raw.baro_alt_meter = baro_report.altitude; // Altitude in meters - raw.baro_temp_celcius = baro_report.temperature; // Temperature in degrees celcius + raw.baro_pres_mbar = _barometer.pressure; // Pressure in mbar + raw.baro_alt_meter = _barometer.altitude; // Altitude in meters + raw.baro_temp_celcius = _barometer.temperature; // Temperature in degrees celcius raw.baro_counter++; } @@ -988,29 +994,72 @@ Sensors::adc_poll(struct sensor_combined_s &raw) for (unsigned i = 0; i < sizeof(buf_adc) / sizeof(buf_adc[0]); i++) { - if (ret >= sizeof(buf_adc[0]) && ADC_BATTERY_VOLTAGE_CHANNEL == buf_adc[i].am_channel) { - /* Voltage in volts */ - float voltage = (buf_adc[i].am_data * _parameters.battery_voltage_scaling); + if (ret >= (int)sizeof(buf_adc[0])) { - if (voltage > VOLTAGE_BATTERY_IGNORE_THRESHOLD_VOLTS) { + if (ADC_BATTERY_VOLTAGE_CHANNEL == buf_adc[i].am_channel) { + /* Voltage in volts */ + float voltage = (buf_adc[i].am_data * _parameters.battery_voltage_scaling); - /* one-time initialization of low-pass value to avoid long init delays */ - if (_battery_status.voltage_v < 3.0f) { - _battery_status.voltage_v = voltage; - } + if (voltage > VOLTAGE_BATTERY_IGNORE_THRESHOLD_VOLTS) { + + /* one-time initialization of low-pass value to avoid long init delays */ + if (_battery_status.voltage_v < 3.0f) { + _battery_status.voltage_v = voltage; + } + + _battery_status.timestamp = hrt_absolute_time(); + _battery_status.voltage_v = (BAT_VOL_LOWPASS_1 * (_battery_status.voltage_v + BAT_VOL_LOWPASS_2 * voltage));; + /* current and discharge are unknown */ + _battery_status.current_a = -1.0f; + _battery_status.discharged_mah = -1.0f; + + /* announce the battery voltage if needed, just publish else */ + if (_battery_pub > 0) { + orb_publish(ORB_ID(battery_status), _battery_pub, &_battery_status); + + } else { + _battery_pub = orb_advertise(ORB_ID(battery_status), &_battery_status); + } + } + + } else if (ADC_AIRSPEED_VOLTAGE_CHANNEL == buf_adc[i].am_channel) { + + /* calculate airspeed, raw is the difference from */ + + float voltage = buf_adc[i].am_data / 4096.0f; + + /** + * The voltage divider pulls the signal down, only act on + * a valid voltage from a connected sensor + */ + if (voltage > 0.4f) { + + float pres_raw = fabsf(voltage - (3.3f / 2.0f)); + float pres_mbar = pres_raw * (3.3f / 5.0f) * 10.0f; + + float airspeed_true = calc_true_airspeed(pres_mbar + _barometer.pressure, + _barometer.pressure, _barometer.temperature - 5.0f); + // XXX HACK - true temperature is much less than indicated temperature in baro, + // subtract 5 degrees in an attempt to account for the electrical upheating of the PCB + + float airspeed_indicated = calc_indicated_airspeed(pres_mbar + _barometer.pressure, + _barometer.pressure, _barometer.temperature - 5.0f); + // XXX HACK - _battery_status.timestamp = hrt_absolute_time(); - _battery_status.voltage_v = (BAT_VOL_LOWPASS_1 * (_battery_status.voltage_v + BAT_VOL_LOWPASS_2 * voltage));; - /* current and discharge are unknown */ - _battery_status.current_a = -1.0f; - _battery_status.discharged_mah = -1.0f; + _differential_pressure.timestamp = hrt_absolute_time(); + _differential_pressure.static_pressure_mbar = _barometer.pressure; + _differential_pressure.differential_pressure_mbar = pres_mbar; + _differential_pressure.temperature_celcius = _barometer.temperature; + _differential_pressure.indicated_airspeed_m_s = airspeed_indicated; + _differential_pressure.true_airspeed_m_s = airspeed_true; - /* announce the battery voltage if needed, just publish else */ - if (_battery_pub > 0) { - orb_publish(ORB_ID(battery_status), _battery_pub, &_battery_status); + /* announce the airspeed if needed, just publish else */ + if (_airspeed_pub > 0) { + orb_publish(ORB_ID(differential_pressure), _airspeed_pub, &_differential_pressure); - } else { - _battery_pub = orb_advertise(ORB_ID(battery_status), &_battery_status); + } else { + _airspeed_pub = orb_advertise(ORB_ID(differential_pressure), &_differential_pressure); + } } } @@ -1114,7 +1163,7 @@ Sensors::ppm_poll() } /* reverse channel if required */ - if (i == _rc.function[THROTTLE]) { + if (i == (int)_rc.function[THROTTLE]) { if ((int)_parameters.rev[i] == -1) { _rc.chan[i].scaled = 1.0f + -1.0f * _rc.chan[i].scaled; } |