Line data    Source code

       1             : /*
       2             :    This program is free software: you can redistribute it and/or modify
       3             :    it under the terms of the GNU General Public License as published by
       4             :    the Free Software Foundation, either version 3 of the License, or
       5             :    (at your option) any later version.
       6             : 
       7             :    This program is distributed in the hope that it will be useful,
       8             :    but WITHOUT ANY WARRANTY; without even the implied warranty of
       9             :    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      10             :    GNU General Public License for more details.
      11             : 
      12             :    You should have received a copy of the GNU General Public License
      13             :    along with this program.  If not, see <http://www.gnu.org/licenses/>.
      14             :  */
      15             : 
      16             : #include <AP_HAL/AP_HAL.h>
      17             : #include <AP_AHRS/AP_AHRS.h>
      18             : #include "AP_OpticalFlow_MSP.h"
      19             : 
      20             : #if HAL_MSP_OPTICALFLOW_ENABLED
      21             : 
      22             : #define OPTFLOW_MSP_TIMEOUT_SEC 0.5f // 2Hz
      23             : 
      24             : extern const AP_HAL::HAL& hal;
      25             : 
      26             : using namespace MSP;
      27             : 
      28             : // detect the device
      29           0 : AP_OpticalFlow_MSP *AP_OpticalFlow_MSP::detect(AP_OpticalFlow &_frontend)
      30             : {
      31             :     // we assume msp messages will be sent into this driver
      32           0 :     return NEW_NOTHROW AP_OpticalFlow_MSP(_frontend);
      33             : }
      34             : 
      35             : // read latest values from sensor and fill in x,y and totals.
      36           0 : void AP_OpticalFlow_MSP::update(void)
      37             : {
      38             :     // record gyro values as long as they are being used
      39             :     // the sanity check of dt below ensures old gyro values are not used
      40           0 :     if (gyro_sum_count < 1000) {
      41           0 :         const Vector3f& gyro = AP::ahrs().get_gyro();
      42           0 :         gyro_sum.x += gyro.x;
      43           0 :         gyro_sum.y += gyro.y;
      44           0 :         gyro_sum_count++;
      45             :     }
      46             : 
      47             :     // return without updating state if no readings
      48           0 :     if (count == 0) {
      49           0 :         return;
      50             :     }
      51             : 
      52           0 :     struct AP_OpticalFlow::OpticalFlow_state state {};
      53             : 
      54           0 :     state.surface_quality = quality_sum / count;
      55             : 
      56             :     // calculate dt
      57           0 :     const float dt = (latest_frame_us - prev_frame_us) * 1.0e-6;
      58           0 :     prev_frame_us = latest_frame_us;
      59             : 
      60             :     // sanity check dt
      61           0 :     if (is_positive(dt) && (dt < OPTFLOW_MSP_TIMEOUT_SEC)) {
      62             :         // calculate flow values
      63           0 :         const float flow_scale_factor_x = 1.0f + 0.001f * _flowScaler().x;
      64           0 :         const float flow_scale_factor_y = 1.0f + 0.001f * _flowScaler().y;
      65             : 
      66             :         // copy flow rates to state structure
      67           0 :         state.flowRate = { ((float)flow_sum.x / count) * flow_scale_factor_x * dt,
      68           0 :                            ((float)flow_sum.y / count) * flow_scale_factor_y * dt};
      69             : 
      70             :         // copy average body rate to state structure
      71           0 :         state.bodyRate = { gyro_sum.x / gyro_sum_count, gyro_sum.y / gyro_sum_count };
      72             : 
      73             :         // invert flow vector to align it with default sensor orientation (required on matek 3901)
      74           0 :         state.flowRate *= -1;
      75             : 
      76             :         // we only apply yaw to flowRate as body rate comes from AHRS
      77           0 :         _applyYaw(state.flowRate);
      78             :     } else {
      79             :         // first frame received in some time so cannot calculate flow values
      80           0 :         state.flowRate.zero();
      81           0 :         state.bodyRate.zero();
      82             :     }
      83             : 
      84           0 :     _update_frontend(state);
      85             : 
      86             :     // reset local buffers
      87           0 :     flow_sum.zero();
      88           0 :     quality_sum = 0;
      89           0 :     count = 0;
      90             : 
      91             :     // reset gyro sum
      92           0 :     gyro_sum.zero();
      93           0 :     gyro_sum_count = 0;
      94             : }
      95             : 
      96             : // handle OPTICAL_FLOW msp messages
      97           0 : void AP_OpticalFlow_MSP::handle_msp(const MSP::msp_opflow_data_message_t &pkt)
      98             : {
      99             :     // record time message was received
     100             :     // ToDo: add jitter correction
     101           0 :     latest_frame_us = AP_HAL::micros64();
     102             : 
     103             :     // add sensor values to sum
     104           0 :     flow_sum.x += pkt.motion_x;
     105           0 :     flow_sum.y += pkt.motion_y;
     106           0 :     quality_sum += (int)pkt.quality * 100 / 255;
     107           0 :     count++;
     108           0 : }
     109             : 
     110             : #endif // HAL_MSP_OPTICALFLOW_ENABLED