mirror of https://github.com/ArduPilot/ardupilot
132 lines
4.3 KiB
C++
132 lines
4.3 KiB
C++
/*
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* AP_OpticalFlow_SITL.cpp - SITL emulation of optical flow sensor.
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*/
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#include <AP_HAL/AP_HAL.h>
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#if CONFIG_HAL_BOARD == HAL_BOARD_SITL
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#include "AP_OpticalFlow_SITL.h"
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extern const AP_HAL::HAL& hal;
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AP_OpticalFlow_SITL::AP_OpticalFlow_SITL(OpticalFlow &_frontend) :
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OpticalFlow_backend(_frontend),
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_sitl(AP::sitl())
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{
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}
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void AP_OpticalFlow_SITL::init(void)
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{
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}
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void AP_OpticalFlow_SITL::update(void)
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{
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if (!_sitl->flow_enable) {
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return;
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}
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// update at the requested rate
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uint32_t now = AP_HAL::millis();
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if (now - last_flow_ms < 1000*(1.0f/_sitl->flow_rate)) {
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return;
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}
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last_flow_ms = now;
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Vector3f gyro(radians(_sitl->state.rollRate),
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radians(_sitl->state.pitchRate),
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radians(_sitl->state.yawRate));
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OpticalFlow::OpticalFlow_state state;
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// NED velocity vector in m/s
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Vector3f velocity(_sitl->state.speedN,
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_sitl->state.speedE,
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_sitl->state.speedD);
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// a rotation matrix following DCM conventions
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Matrix3f rotmat;
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rotmat.from_euler(radians(_sitl->state.rollDeg),
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radians(_sitl->state.pitchDeg),
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radians(_sitl->state.yawDeg));
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state.surface_quality = 51;
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// sensor position offset in body frame
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Vector3f posRelSensorBF = _sitl->optflow_pos_offset;
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// estimate range to centre of image
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float range;
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if (rotmat.c.z > 0.05f && _sitl->height_agl > 0) {
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Vector3f relPosSensorEF = rotmat * posRelSensorBF;
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range = (_sitl->height_agl - relPosSensorEF.z) / rotmat.c.z;
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} else {
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range = 1e38f;
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}
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// Calculate relative velocity in sensor frame assuming no misalignment between sensor and vehicle body axes
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Vector3f relVelSensor = rotmat.mul_transpose(velocity);
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// correct relative velocity for rotation rates and sensor offset
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relVelSensor += gyro % posRelSensorBF;
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// scaling based on parameters
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const Vector2f flowScaler = _flowScaler();
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const float flowScaleFactorX = 1.0f + 0.001f * flowScaler.x;
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const float flowScaleFactorY = 1.0f + 0.001f * flowScaler.y;
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// Divide velocity by range and add body rates to get predicted sensed angular
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// optical rates relative to X and Y sensor axes assuming no misalignment or scale
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// factor error. Note - these are instantaneous values. The sensor sums these values across the interval from the last
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// poll to provide a delta angle across the interface
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state.flowRate.x = (-relVelSensor.y/range + gyro.x + _sitl->flow_noise * rand_float()) * flowScaleFactorX;
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state.flowRate.y = (relVelSensor.x/range + gyro.y + _sitl->flow_noise * rand_float()) * flowScaleFactorY;
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// The flow sensors body rates are assumed to be the same as the vehicle body rates (ie no misalignment)
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// Note - these are instantaneous values. The sensor sums these values across the interval from the last
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// poll to provide a delta angle across the interface.
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state.bodyRate = Vector2f(gyro.x, gyro.y);
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optflow_data[next_optflow_index++] = state;
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if (next_optflow_index >= optflow_delay+1) {
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next_optflow_index = 0;
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}
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state = optflow_data[next_optflow_index];
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if (_sitl->flow_delay != optflow_delay) {
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// cope with updates to the delay control
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if (_sitl->flow_delay > 0 &&
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(uint8_t)(_sitl->flow_delay) > ARRAY_SIZE(optflow_data)) {
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_sitl->flow_delay = ARRAY_SIZE(optflow_data);
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}
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optflow_delay = _sitl->flow_delay;
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for (uint8_t i=0; i<optflow_delay; i++) {
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optflow_data[i] = state;
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}
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}
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_applyYaw(state.flowRate);
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// copy results to front end
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_update_frontend(state);
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}
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#endif // CONFIG_HAL_BOARD
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