mirror of https://github.com/ArduPilot/ardupilot
112 lines
3.4 KiB
C++
112 lines
3.4 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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#include "AP_OpticalFlow_MAV.h"
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#if AP_OPTICALFLOW_MAV_ENABLED
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#include <AP_HAL/AP_HAL.h>
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#include <AP_AHRS/AP_AHRS.h>
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#define OPTFLOW_MAV_TIMEOUT_SEC 0.5f
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// detect the device
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AP_OpticalFlow_MAV *AP_OpticalFlow_MAV::detect(AP_OpticalFlow &_frontend)
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{
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// we assume mavlink messages will be sent into this driver
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AP_OpticalFlow_MAV *sensor = NEW_NOTHROW AP_OpticalFlow_MAV(_frontend);
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return sensor;
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}
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// read latest values from sensor and fill in x,y and totals.
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void AP_OpticalFlow_MAV::update(void)
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{
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// record gyro values as long as they are being used
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// the sanity check of dt below ensures old gyro values are not used
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if (gyro_sum_count < 1000) {
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const Vector3f& gyro = AP::ahrs().get_gyro();
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gyro_sum.x += gyro.x;
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gyro_sum.y += gyro.y;
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gyro_sum_count++;
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}
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// return without updating state if no readings
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if (count == 0) {
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return;
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}
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struct AP_OpticalFlow::OpticalFlow_state state {};
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state.surface_quality = quality_sum / count;
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// calculate dt
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const float dt = (latest_frame_us - prev_frame_us) * 1.0e-6;
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prev_frame_us = latest_frame_us;
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// sanity check dt
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if (is_positive(dt) && (dt < OPTFLOW_MAV_TIMEOUT_SEC)) {
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// calculate flow values
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const float flow_scale_factor_x = 1.0f + 0.001f * _flowScaler().x;
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const float flow_scale_factor_y = 1.0f + 0.001f * _flowScaler().y;
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// copy flow rates to state structure
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state.flowRate = { ((float)flow_sum.x / count) * flow_scale_factor_x * dt,
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((float)flow_sum.y / count) * flow_scale_factor_y * dt };
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// copy average body rate to state structure
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state.bodyRate = { gyro_sum.x / gyro_sum_count, gyro_sum.y / gyro_sum_count };
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// we only apply yaw to flowRate as body rate comes from AHRS
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_applyYaw(state.flowRate);
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} else {
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// first frame received in some time so cannot calculate flow values
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state.flowRate.zero();
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state.bodyRate.zero();
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}
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_update_frontend(state);
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// reset local buffers
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flow_sum.zero();
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quality_sum = 0;
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count = 0;
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// reset gyro sum
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gyro_sum.zero();
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gyro_sum_count = 0;
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}
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// handle OPTICAL_FLOW mavlink messages
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void AP_OpticalFlow_MAV::handle_msg(const mavlink_message_t &msg)
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{
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mavlink_optical_flow_t packet;
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mavlink_msg_optical_flow_decode(&msg, &packet);
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// record time message was received
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// ToDo: add jitter correction
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latest_frame_us = AP_HAL::micros64();
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// add sensor values to sum
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flow_sum.x += packet.flow_x;
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flow_sum.y += packet.flow_y;
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quality_sum += packet.quality;
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count++;
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// take sensor id from message
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sensor_id = packet.sensor_id;
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}
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#endif // AP_OPTICALFLOW_MAV_ENABLED
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