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author | Lorenz Meier <lm@inf.ethz.ch> | 2013-02-26 21:17:48 +0100 |
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committer | Lorenz Meier <lm@inf.ethz.ch> | 2013-02-26 21:17:48 +0100 |
commit | c848fd1d6327fd3aaea4f1fa3ceb0b45d7f54ee5 (patch) | |
tree | 78d641da99e42cf33b879c67993e7690302444c3 /apps/sensors/sensors.cpp | |
parent | dffe05d8934f69542dc2473f77ed019528ffba57 (diff) | |
parent | a9b933b7e6652ba7d710ffe356a1843329ad9520 (diff) | |
download | px4-firmware-c848fd1d6327fd3aaea4f1fa3ceb0b45d7f54ee5.tar.gz px4-firmware-c848fd1d6327fd3aaea4f1fa3ceb0b45d7f54ee5.tar.bz2 px4-firmware-c848fd1d6327fd3aaea4f1fa3ceb0b45d7f54ee5.zip |
Merged master
Diffstat (limited to 'apps/sensors/sensors.cpp')
-rw-r--r-- | apps/sensors/sensors.cpp | 29 |
1 files changed, 18 insertions, 11 deletions
diff --git a/apps/sensors/sensors.cpp b/apps/sensors/sensors.cpp index 19cb13d06..9b95c0939 100644 --- a/apps/sensors/sensors.cpp +++ b/apps/sensors/sensors.cpp @@ -187,6 +187,7 @@ private: float mag_scale[3]; float accel_offset[3]; float accel_scale[3]; + float airspeed_offset; int rc_type; @@ -235,6 +236,7 @@ private: param_t accel_scale[3]; param_t mag_offset[3]; param_t mag_scale[3]; + param_t airspeed_offset; param_t rc_map_roll; param_t rc_map_pitch; @@ -480,6 +482,9 @@ Sensors::Sensors() : _parameter_handles.mag_scale[1] = param_find("SENS_MAG_YSCALE"); _parameter_handles.mag_scale[2] = param_find("SENS_MAG_ZSCALE"); + /*Airspeed offset */ + _parameter_handles.airspeed_offset = param_find("SENS_VAIR_OFF"); + _parameter_handles.battery_voltage_scaling = param_find("BAT_V_SCALING"); /* fetch initial parameter values */ @@ -687,6 +692,9 @@ Sensors::parameters_update() param_get(_parameter_handles.mag_scale[1], &(_parameters.mag_scale[1])); param_get(_parameter_handles.mag_scale[2], &(_parameters.mag_scale[2])); + /* Airspeed offset */ + param_get(_parameter_handles.airspeed_offset, &(_parameters.airspeed_offset)); + /* scaling of ADC ticks to battery voltage */ if (param_get(_parameter_handles.battery_voltage_scaling, &(_parameters.battery_voltage_scaling)) != OK) { warnx("Failed updating voltage scaling param"); @@ -993,7 +1001,7 @@ Sensors::adc_poll(struct sensor_combined_s &raw) /* look for battery channel */ for (unsigned i = 0; i < sizeof(buf_adc) / sizeof(buf_adc[0]); i++) { - + if (ret >= (int)sizeof(buf_adc[0])) { if (ADC_BATTERY_VOLTAGE_CHANNEL == buf_adc[i].am_channel) { @@ -1025,8 +1033,7 @@ Sensors::adc_poll(struct sensor_combined_s &raw) } 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; + float voltage = (float)(buf_adc[i].am_data ) * 3.3f / 4096.0f * 2.0f; //V_ref/4096 * (voltage divider factor) /** * The voltage divider pulls the signal down, only act on @@ -1034,24 +1041,24 @@ Sensors::adc_poll(struct sensor_combined_s &raw) */ 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 diff_pres_pa = (voltage - _parameters.airspeed_offset) * 1000.0f; //for MPXV7002DP sensor - float airspeed_true = calc_true_airspeed(pres_mbar + _barometer.pressure, - _barometer.pressure, _barometer.temperature - 5.0f); + float airspeed_true = calc_true_airspeed(diff_pres_pa + _barometer.pressure*1e2f, + _barometer.pressure*1e2f, _barometer.temperature - 5.0f); //factor 1e2 for conversion from mBar to Pa // 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 + float airspeed_indicated = calc_indicated_airspeed(diff_pres_pa); + + //printf("voltage: %.4f, diff_pres_pa %.4f, baro press %.4f Pa, v_ind %.4f, v_true %.4f\n", (double)voltage, (double)diff_pres_pa, (double)_barometer.pressure*1e2f, (double)airspeed_indicated, (double)airspeed_true); _differential_pressure.timestamp = hrt_absolute_time(); _differential_pressure.static_pressure_mbar = _barometer.pressure; - _differential_pressure.differential_pressure_mbar = pres_mbar; + _differential_pressure.differential_pressure_mbar = diff_pres_pa*1e-2f; _differential_pressure.temperature_celcius = _barometer.temperature; _differential_pressure.indicated_airspeed_m_s = airspeed_indicated; _differential_pressure.true_airspeed_m_s = airspeed_true; + _differential_pressure.voltage = voltage; /* announce the airspeed if needed, just publish else */ if (_airspeed_pub > 0) { |