Study on Development of Handling System for Japanese Pear Havesting

本研究旨在开发日本梨采收时的搬运系统。本研究以日本梨为研究对象，探讨其重量与果皮颜色之量测方法，并制作出一台机械手。梨皮色的估计是根据以往试验中测得的L^<**>a^<**>B^<**>颜色系统的数据进行的。为了测量梨赤道部和底部的表皮颜色，研究了自然光和人工光的光源选择，以及颜色传感器对入射光的检测。在使用人造光源的情况下，检查光发射的时间间隔、调制和控制。由于颜色传感器的输出信号受入射光的亮度和色温的影响，因此采用对数放大器将输出信号转换为线性值。通过计算颜色传感器的R、G、B三个输出值和照度计的亮度值来进行色温的补偿。由于这些操作非常复杂且同步，因此尝试了多CPU系统的分散操作。其次，试制了一个称重传感器的三指机械手。称重传感器用于测量水果的重量。每个手指有一个关节，并由两相混合式步进电机驱动。上手指有三个压力传感器，用于检测手指与水果之间的接触压力。该传感器采用导电橡胶材料制成。这些手指由自学习自适应控制系统控制。该控制系统通过实时检测压力传感器的接触力来确定水果的最佳抓取力。

This study aimed to develope the handling system of Japanese pear at harvesting. In this study, the measurement of the weight and the skin color of Japanese pear were investigated and a trial manipulator was made. The estimation of the skin color of pear was based on the data by L^<**>a^<**>b^<**> color system measured in the past experiment. To measure the skin color of pear on the equatorial part and the bottom, it was investigated about the selection of the light source, the natural light or the artificial light, and the application of the color sensor for detecting the incident light. In case of using the artificial light source, the time interval, the modulation, and the control of the light emission were examined. As the output signal of color sensor was affected by the lightness and the color temperature of the incident light, so a logarithmic amplifier was applied to cenvert the output signal to the linear value. The compensation of the color temperature was done by the calculation of three output value of R,G,B from the color sensor and the lightness value by a lux meter. As these operations were very complicated and synchronously, so the dispersive operation with the multi CPU system was tried. Next, three fingers type manipulator with one loadcell was made by trial. The loadcell was used to measure the weight of fruit. Each finger has one joint and was driven by a 2-phase hybrid type stepping motor. The upper finger has three pressure sensors for detecting constact pressure between the finger and the fruit. The sensor was contructed by the electro-conductive rubber. These fingers were controlled by a self learning adaptive control system. This control system can decide the optimum grasping force of fruits by detecting the contact force of pressure sensors at the realtime.