mirror of https://github.com/ArduPilot/ardupilot
126 lines
3.8 KiB
C++
126 lines
3.8 KiB
C++
/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
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#include "AP_InertialSensor_Oilpan.h"
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// ADC channel mappings on for the APM Oilpan
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// Sensors: GYROX, GYROY, GYROZ, ACCELX, ACCELY, ACCELZ
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const uint8_t AP_InertialSensor_Oilpan::_sensors[6] = { 1, 2, 0, 4, 5, 6 };
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// ADC result sign adjustment for sensors.
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const int8_t AP_InertialSensor_Oilpan::_sensor_signs[6] =
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{ 1, -1, -1, 1, -1, -1 };
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// ADC channel reading the gyro temperature
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const uint8_t AP_InertialSensor_Oilpan::_gyro_temp_ch = 3;
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// Maximum possible value returned by an offset-corrected sensor channel
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const float AP_InertialSensor_Oilpan::_adc_constraint = 900;
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// ADC : Voltage reference 3.3v / 12bits(4096 steps) => 0.8mV/ADC step
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// ADXL335 Sensitivity(from datasheet) => 330mV/g,
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// 0.8mV/ADC step => 330/0.8 = 412
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// Tested value : 418
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// Oilpan accelerometer scaling & offsets
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#define OILPAN_ACCEL_SCALE_1G (GRAVITY * 2.0 / (2465.0 - 1617.0))
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#define OILPAN_RAW_ACCEL_OFFSET ((2465.0 + 1617.0) * 0.5)
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#define OILPAN_RAW_GYRO_OFFSET 1658.0
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#define ToRad(x) (x*0.01745329252) // *pi/180
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// IDG500 Sensitivity (from datasheet) => 2.0mV/degree/s,
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// 0.8mV/ADC step => 0.8/3.33 = 0.4
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// Tested values : 0.4026, ?, 0.4192
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const float AP_InertialSensor_Oilpan::_gyro_gain_x = ToRad(0.4);
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const float AP_InertialSensor_Oilpan::_gyro_gain_y = ToRad(0.41);
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const float AP_InertialSensor_Oilpan::_gyro_gain_z = ToRad(0.41);
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/* ------ Public functions -------------------------------------------*/
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AP_InertialSensor_Oilpan::AP_InertialSensor_Oilpan( AP_ADC * adc ) :
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_adc(adc)
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{
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}
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uint16_t AP_InertialSensor_Oilpan::_init_sensor( Sample_rate sample_rate)
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{
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_adc->Init();
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switch (sample_rate) {
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case RATE_50HZ:
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_sample_threshold = 20;
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break;
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case RATE_100HZ:
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_sample_threshold = 10;
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break;
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case RATE_200HZ:
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_sample_threshold = 5;
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break;
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}
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#if defined(DESKTOP_BUILD)
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return AP_PRODUCT_ID_SITL;
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#elif defined(__AVR_ATmega1280__)
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return AP_PRODUCT_ID_APM1_1280;
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#else
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return AP_PRODUCT_ID_APM1_2560;
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#endif
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}
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bool AP_InertialSensor_Oilpan::update()
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{
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float adc_values[6];
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Vector3f gyro_offset = _gyro_offset.get();
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Vector3f accel_scale = _accel_scale.get();
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Vector3f accel_offset = _accel_offset.get();
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_delta_time_micros = _adc->Ch6(_sensors, adc_values);
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_temp = _adc->Ch(_gyro_temp_ch);
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_gyro.x = _gyro_gain_x * _sensor_signs[0] * ( adc_values[0] - OILPAN_RAW_GYRO_OFFSET );
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_gyro.y = _gyro_gain_y * _sensor_signs[1] * ( adc_values[1] - OILPAN_RAW_GYRO_OFFSET );
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_gyro.z = _gyro_gain_z * _sensor_signs[2] * ( adc_values[2] - OILPAN_RAW_GYRO_OFFSET );
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_gyro -= gyro_offset;
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_accel.x = accel_scale.x * _sensor_signs[3] * (adc_values[3] - OILPAN_RAW_ACCEL_OFFSET) * OILPAN_ACCEL_SCALE_1G;
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_accel.y = accel_scale.y * _sensor_signs[4] * (adc_values[4] - OILPAN_RAW_ACCEL_OFFSET) * OILPAN_ACCEL_SCALE_1G;
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_accel.z = accel_scale.z * _sensor_signs[5] * (adc_values[5] - OILPAN_RAW_ACCEL_OFFSET) * OILPAN_ACCEL_SCALE_1G;
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_accel -= accel_offset;
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/*
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* X = 1619.30 to 2445.69
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* Y = 1609.45 to 2435.42
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* Z = 1627.44 to 2434.82
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*/
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return true;
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}
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bool AP_InertialSensor_Oilpan::new_data_available( void )
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{
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return _adc->new_data_available(_sensors);
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}
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float AP_InertialSensor_Oilpan::temperature() {
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return _temp;
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}
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uint32_t AP_InertialSensor_Oilpan::get_delta_time_micros() {
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return _delta_time_micros;
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}
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/* ------ Private functions -------------------------------------------*/
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// return the oilpan gyro drift rate in radian/s/s
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float AP_InertialSensor_Oilpan::get_gyro_drift_rate(void)
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{
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// 3.0 degrees/second/minute
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return ToRad(3.0/60);
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}
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// get number of samples read from the sensors
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uint16_t AP_InertialSensor_Oilpan::num_samples_available()
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{
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return _adc->num_samples_available(_sensors) / _sample_threshold;
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}
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