1997 Fiscal Year Final Research Report Summary

Study on Development of Handling System for Japanese Pear Havesting

Research Project

Project/Area Number	08660313
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	農業機械学
Research Institution	Kobe University
Principal Investigator	KAWAMURA Tsuneo Faculty of Agriculture, Kobe University, Associate Professor, 農学部, 助教授 (50107984)
Project Period (FY)	1996 – 1997
Keywords	Manipulator / Contact Pressure Sensor / Force Control System / Multi Joint Type Finger
Research Abstract	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.