Design And Experiment Of Photoelectric Sensor Device For Rapeseed And Wheat

The precision seed metering device is the key component of the planter,which directly determines the seeding quality during the sowing process.There are many researches on the detection of larger particle size seed streams in China,but the detection of small particle seed streams such as rapeseed is relatively rare.The real-time compatible detection of the amount of rapeseed and wheat seeds in the combination of rapeseed and wheat combined with live broadcast machine has important practical significance for improving seeding quality,uniformity of seeding and detection of leaking detection,and also realizes informationization and intelligence of sowing.Based on the analysis of seeding detection systems at home and abroad,this paper proposes a method based on diffuse reflection type rapeseed and wheat seed flow sensing and a method based on thin-face laser and silicon photocell,and designs two sets of seed flow sensing devices.Based on the diffuse reflection type rapeseed and wheat seed flow sensing device and the thin-surface laser-based rapeseed and wheat seed flow sensing device,the corresponding experimental research is carried out.The specific research contents and conclusions are as follows:(1)Based on the diffuse reflection photoelectric rapeseed and wheat seed flow sensing device,Based on the analysis of the photoelectric signal characteristics of rapeseed and wheat seeds passing through the detection zone,a diffuse reflection detection method for rapeseed and wheat seeds was explored.Structural parameters such as the inner diameter of the catheter,the relative angle of the transceiver diode,and the length of the catheter are designed.By designing the signal acquisition system,the micro-optical signal is converted into a square wave pulse signal through the circuit conditioning process such as amplification,half-wave rectification,voltage comparison,and monostable triggering,and the timing of the single-chip microcomputer is used to collect and process the rapeseed and wheat seed flow.Real-time detection of totals.The counting experiment of the counting instrument shows that the sensing device can detect the total seeding,the frequency of the test is 8.1~20.4 Hz,the detection accuracy of rapeseed is not less than 86.5%,and the accuracy of wheat seed detection is not less than 84.6%.(2)A thin-surface laser rapeseed and wheat seed sensing device was designed.Aiming at the basis of previous research,a thin-film laser emitting module and a photovoltaic effect detection method based on silicon photocells are proposed.According to the plane geometry method,the size of the seed detection area and the specific location of the detection area are calculated,which provides the basis for the structural parameters such as the inner diameter of the catheter,the position of the catheter centerline,the installation position of the laser emitting module and the installation position of the silicon photocell.The device integrates the sensing and display parts,including the seeding port,the upper tube,the lower tube,the seeding port,the thin-surface laser emitting module,the silicon photo cell,the integrated circuit board,the OLED seeding information display screen,and the device is compact.The analysis of the time required for the seed to pass through the thin-faced laser,the rapeseed occlusion signal completes the process response within 3ms,and the wheat seed occlusion signal completes the process response within 7ms.The occluded photoelectric signal is subjected to through-crossing,two-stage amplification,half-wave rectification,voltage comparison,and monostable triggering into a single-pulse signal,and the circuit board is designed and manufactured,and the interrupt is captured by the single-chip time and real-time data processing is performed in real time.The broadcast amount information is displayed,and the blind spot detection of the rapeseed and wheat seed is realized.The rapeseed precision seeding bench test and the wheat granule test showed that the detection accuracy of rapeseed seeds was not less than 98.1% in the range of 8.4 to 32.1 Hz,and the seeding frequency was in the range of 21.5 to 31.2 Hz.The accuracy of wheat seed detection is not less than 95.1%.The field sowing test showed that the accuracy of rapeseed seed detection was not less than 98.6% and the accuracy of wheat seed detection was not less than 95.8%.The illumination conditions and machine vibration had no effect on the detection accuracy of the sensing device.The sensing device provides strong support for the sowing volume detection and the leak detection of the medium and small particle size seeding process.(3)Sensing device detection error analysis and test.Using SLY-C microcomputer automatic counting instrument to simulate the experiment of rapeseed and wheat under different seed frequency,using high-speed photography technology to record the trajectory of seed falling,combined with the waveform generated by digital oscilloscope and actual seeding number,in-depth search the reason for the error has been found through experiments: Based on the diffuse reflection type photoelectric sensing device,the main causes of the error are:(1)detecting the presence of a dead zone,the emitted light generated by the transmitting end has a certain emission angle,and the emission angle is 60°.The diameter of the guide tube is 10 mm.The emitted light does not completely cover the entire pipeline,causing some seeds to fall from the uncovered area and cannot be detected.(2)The emitted light layer has a certain thickness,when two or more seeds are simultaneously tested.When the area is not recognized,it will lead to false detection.The thin-face laser-based oil wheat seed flow sensing device mainly causes the thickness of the emitted thin-face laser layer to be 1 mm.When two or more seeds pass through the 1 mm detection zone at the same time,they cannot be distinguished.When the frequency increases,the detection accuracy will decrease.The root cause is that when the seed frequency increases,the probability that the seed will cross the light layer at the same time increases,so that the probability of two or more seeds being counted as one is increased.Increase,which reduces the detection accuracy.