ardupilot/libraries/AP_InertialSensor/AP_InertialSensor_Oilpan.cpp

151 lines
4.5 KiB
C++

/// -*- tab-width: 4; Mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*-
#include <AP_HAL.h>
#if CONFIG_HAL_BOARD == HAL_BOARD_APM1 || CONFIG_HAL_BOARD == HAL_BOARD_LINUX
#include "AP_InertialSensor_Oilpan.h"
const extern AP_HAL::HAL& hal;
// ADC channel mappings on for the APM Oilpan
// Sensors: GYROX, GYROY, GYROZ, ACCELX, ACCELY, ACCELZ
const uint8_t AP_InertialSensor_Oilpan::_sensors[6] = { 1, 2, 0, 4, 5, 6 };
// ADC result sign adjustment for sensors.
const int8_t AP_InertialSensor_Oilpan::_sensor_signs[6] =
{ 1, -1, -1, 1, -1, -1 };
// ADC channel reading the gyro temperature
const uint8_t AP_InertialSensor_Oilpan::_gyro_temp_ch = 3;
// Maximum possible value returned by an offset-corrected sensor channel
const float AP_InertialSensor_Oilpan::_adc_constraint = 900;
// ADC : Voltage reference 3.3v / 12bits(4096 steps) => 0.8mV/ADC step
// ADXL335 Sensitivity(from datasheet) => 330mV/g,
// 0.8mV/ADC step => 330/0.8 = 412
// Tested value : 418
// Oilpan accelerometer scaling & offsets
#define OILPAN_ACCEL_SCALE_1G (GRAVITY_MSS * 2.0f / (2465.0f - 1617.0f))
#define OILPAN_RAW_ACCEL_OFFSET ((2465.0f + 1617.0f) * 0.5f)
#define OILPAN_RAW_GYRO_OFFSET 1658.0f
#define ToRad(x) radians(x) // *pi/180
// IDG500 Sensitivity (from datasheet) => 2.0mV/degree/s,
// 0.8mV/ADC step => 0.8/3.33 = 0.4
// Tested values : 0.4026, ?, 0.4192
const float AP_InertialSensor_Oilpan::_gyro_gain_x = ToRad(0.4f);
const float AP_InertialSensor_Oilpan::_gyro_gain_y = ToRad(0.41f);
const float AP_InertialSensor_Oilpan::_gyro_gain_z = ToRad(0.41f);
/* ------ Public functions -------------------------------------------*/
AP_InertialSensor_Oilpan::AP_InertialSensor_Oilpan( AP_ADC * adc ) :
AP_InertialSensor(),
_adc(adc)
{
}
uint16_t AP_InertialSensor_Oilpan::_init_sensor( Sample_rate sample_rate)
{
_adc->Init();
switch (sample_rate) {
case RATE_50HZ:
_sample_threshold = 20;
break;
case RATE_100HZ:
_sample_threshold = 10;
break;
case RATE_200HZ:
_sample_threshold = 5;
break;
}
#if defined(__AVR_ATmega1280__)
return AP_PRODUCT_ID_APM1_1280;
#else
return AP_PRODUCT_ID_APM1_2560;
#endif
}
bool AP_InertialSensor_Oilpan::update()
{
if (!wait_for_sample(100)) {
return false;
}
float adc_values[6];
Vector3f gyro_offset = _gyro_offset[0].get();
Vector3f accel_scale = _accel_scale[0].get();
Vector3f accel_offset = _accel_offset[0].get();
_delta_time_micros = _adc->Ch6(_sensors, adc_values);
_temp = _adc->Ch(_gyro_temp_ch);
_gyro[0] = Vector3f(_sensor_signs[0] * ( adc_values[0] - OILPAN_RAW_GYRO_OFFSET ),
_sensor_signs[1] * ( adc_values[1] - OILPAN_RAW_GYRO_OFFSET ),
_sensor_signs[2] * ( adc_values[2] - OILPAN_RAW_GYRO_OFFSET ));
_gyro[0].rotate(_board_orientation);
_gyro[0].x *= _gyro_gain_x;
_gyro[0].y *= _gyro_gain_y;
_gyro[0].z *= _gyro_gain_z;
_gyro[0] -= gyro_offset;
_previous_accel[0] = _accel[0];
_accel[0] = Vector3f(_sensor_signs[3] * (adc_values[3] - OILPAN_RAW_ACCEL_OFFSET),
_sensor_signs[4] * (adc_values[4] - OILPAN_RAW_ACCEL_OFFSET),
_sensor_signs[5] * (adc_values[5] - OILPAN_RAW_ACCEL_OFFSET));
_accel[0].rotate(_board_orientation);
_accel[0].x *= accel_scale.x;
_accel[0].y *= accel_scale.y;
_accel[0].z *= accel_scale.z;
_accel[0] *= OILPAN_ACCEL_SCALE_1G;
_accel[0] -= accel_offset;
/*
* X = 1619.30 to 2445.69
* Y = 1609.45 to 2435.42
* Z = 1627.44 to 2434.82
*/
return true;
}
float AP_InertialSensor_Oilpan::get_delta_time() const {
return _delta_time_micros * 1.0e-6;
}
/* ------ Private functions -------------------------------------------*/
// return the oilpan gyro drift rate in radian/s/s
float AP_InertialSensor_Oilpan::get_gyro_drift_rate(void)
{
// 3.0 degrees/second/minute
return ToRad(3.0/60);
}
// return true if a new sample is available
bool AP_InertialSensor_Oilpan::_sample_available()
{
return (_adc->num_samples_available(_sensors) / _sample_threshold) > 0;
}
bool AP_InertialSensor_Oilpan::wait_for_sample(uint16_t timeout_ms)
{
if (_sample_available()) {
return true;
}
uint32_t start = hal.scheduler->millis();
while ((hal.scheduler->millis() - start) < timeout_ms) {
hal.scheduler->delay_microseconds(100);
if (_sample_available()) {
return true;
}
}
return false;
}
#endif // CONFIG_HAL_BOARD