CAJ | 학술논문

为解决水田激光平地机平地铲高程定位稳定性问题，该文采用试验方法研究了激光接收器的光电转换特征，对光电转换电路和放大电路参数进行了优化设计。并对影响激光接收器光电转换信号幅值的接收距离、太阳辐照度噪声、振动噪声与有效激光信号幅值频率等因素开展了相关性试验。试验结果表明，随着激光接收距离增加，接收到激光能量减小，激光光电转换信号幅值随接收距离增加按负指数衰减；随着阳光辐照度增加，光电转换硅光电池背景电流增加，光电转换效率降低，激光光电转换信号幅值按负指数衰减，而光电转换噪声按指数规律显著增加；机械振动噪声频率相对固定在低频段。在试验分析基础上，该文采用硅光电池内部等效电容和外接电感的直接光电转换电路，将激光脉冲电流信号调制为交流电压信号，优化带通放大电路参数，降低放大电路带宽对阳光辐照噪声和振动噪声的衰减，以提高激光接收器放大电路的信噪比。进一步田间试验表明，当采用定制的福田KF308发射器旋转频率为600 r/min，设计优化后的激光接收器可满足水田激光平地机的高程可靠定位检测要求。
위해결수전격광평지궤평지산고정정위은정성문제，해문채용시험방법연구료격광접수기적광전전환특정，대광전전환전로화방대전로삼수진행료우화설계。병대영향격광접수기광전전환신호폭치적접수거리、태양복조도조성、진동조성여유효격광신호폭치빈솔등인소개전료상관성시험。시험결과표명，수착격광접수거리증가，접수도격광능량감소，격광광전전환신호폭치수접수거리증가안부지수쇠감；수착양광복조도증가，광전전환규광전지배경전류증가，광전전환효솔강저，격광광전전환신호폭치안부지수쇠감，이광전전환조성안지수규률현저증가；궤계진동조성빈솔상대고정재저빈단。재시험분석기출상，해문채용규광전지내부등효전용화외접전감적직접광전전환전로，장격광맥충전류신호조제위교류전압신호，우화대통방대전로삼수，강저방대전로대관대양광복조조성화진동조성적쇠감，이제고격광접수기방대전로적신조비。진일보전간시험표명，당채용정제적복전KF308발사기선전빈솔위600 r/min，설계우화후적격광접수기가만족수전격광평지궤적고정가고정위검측요구。
Because of its high efficiency and leveling precision, the laser leveler for paddy fields has received widespread attention in the mechanization of rice planting. The laser receiver is the elevation sensor component of a laser leveler for paddy fields, and the effective distances of the laser leveler for paddy fields are mainly decided by the noise-rejection performance of the photoelectric conversion and amplifier circuit. In extension work, due to strong solar irradiance and vibration the laser receiver may output wrong height position information, reducing leveling precision and work efficiency. In order to improve the reliability of elevation measurements, the photoelectric conversion and amplifier circuit of the laser receiver were optimized by using the experimental methods in this study. Laser receiving distance, energy conversion, and the noise and frequency characteristics of the laser receiver were selected as experimental variables. 2CR93 silicon photoelectric cells were selected as the laser photoelectric conversion element in this research. The laser pulse energy received by the silicon photocell was converted to an electrical signal. The signal energy is determined by the optical filter mode, laser spot and sweeping duration across the silicon photocell. As the receiving distance increases, the diameter of the laser spot expands, and both the sweeping duration across the silicon photocell and the laser energy received by the silicon photocell decrease. With increasing receiver distance, the short circuit current and open circuit voltage of the silicon photocell were obtained by experiments under two optical filter modes. When the receiving distance was over 175 meters, the short circuit current of the silicon photocells were approximately equal under each filter mode. When the receiving distance was over 50 meters, the open circuit voltages of the silicon photocells were also approximately equal. The bare 2CR93 silicon photocell was used as direct photoelectric converting device. With a 100μH external inductance, the photoelectric conversion signal was modulated into a sinusoidal signal. With 4 parallel silicon photoelectric cells, the modulation frequency was 63.9 kHz. With 8 cells, the frequency was 43.5 kHz. The 2CR93 silicon solar cell equivalent diode capacitance was 16 nF. The laser receiver receives the laser signal and other external noise, including the mechanical vibration noise, solar irradiance noise and various electrical noises. The photoelectric conversion noise experiment result shows that with increasing background solar power, the laser signal peak value decreases and the noise peak value rises. Vibration noise affected only the low-frequency system. According to the test results, the photoelectric conversion circuit and amplification circuit parameters were optimized in this paper. The appropriate 100μH inductance was selected;the photoelectric conversion signal was modulated into a sinusoidal signal. A smaller bandwidth could reduce the solar noise interference on the laser receiver;with an optimized, infinite-gain, multiple negative feedback, two-order bandpass amplifier circuit parameters could reduce vibration noise. Field testing results showed that when the transmitter was a Futian KF308, rotating frequency was 600 r/min, a multilevel, narrow-band amplifier can reduce the noise caused by solar irradiance, and the bandpass amplifier can reduce the noise caused by mechanical vibrations. The optimized laser receiver met height position requirements of a laser leveler for paddy fields.