Development of Wearable-Agri-Robot ~ mechanism for agricultural work ~

Recently, It has become a rapidly aging society. Coupled with a decrease in the number of farmers, this has becomes a serious problem in agriculture. Agricultural work includes a great deal of heavy work and special work postures, imposing a large physical strain on farmers. Therefore, we developed the Wearable Agri-Robot, which was designed as an exoskeletal mechanism to assist in the wearer’s work. This study evaluates the degree of freedom realized by forcusing on the range of motion of the joints. Using this method, we evaluated the articular structure of the Wearable Agri-Robot. We investigated the possibility of using it to assist in agricultural work by analyzing the motion required for thie type of work. In this work, we narrowed down the intended operations to the harvesting of Japanese radishes, and validated the effect of the Wearable Agri-Robot on the wearer using myoelectric potential measurement. As a result, it was ascertained that wearing the Wearable Agri-Robot could alleviate the burden on wearer by assisting with agricultural work. £. INTRODUCTION HERE are serious problems facing an aging society with a falling birthrate. We do not propose a concrete problem solving method. It is has been estimated that in our super-aging society one person in three was 65 years old or older in 2005. Although the present population of the agricultural work force is 3.12 million people, it decreases every year. In addition, about 59 % are 65 years old or older, with this ratio on the increase. This represents a remarkable increase in the load placed on the supporters of agriculture. Moreover, the food self-sufficiency rate for the major advanced countries is 130% for France, 119% for the United States, 91% for German, 74% for Britain, and 40% for Japan, according to an investigation by the Ministry of Agriculture, Forestry, and Fisheries. Japan has the lowest level. This fact shows the importance of improving agrigultural efficiency. Numerous pieces of farm equipment have been introduced in an attempt to achieve this efficiency improvement. For instance, combines, etc. are used to cultivate and harvest rice fields. However, such large-scale farming machines are limited to large-scale farms, which only constitute a part of the crops. It is not more effective willingly by mechanization and enough in a small-scale farm, slope arable land, and the bottleneck in the house, etc. The same degree of advancement has not been made in the mechanization of the harvesting work for fruits and vegetables, such as the cucumbers, eggplants, and tomatoes or for the pruning hybridization, fruit thinning, and harvesting of fruit trees. Much work must still be done by hand. (a) (b) (c) Fig.1 Wearable-Agri-Robot. (a) shows front view. (b) shows side view (c) shows back view Thus, we developed an exoskeleton type Wearable-Agri-Robot that can be used by an individual farmer. Agriculture labor involves the delicate work of pruning branches, judging the appropriate time for harvesting, etc. With the aim of assisting in this type of labor [1]-[3], the Exoskeleton type Wearable-Agri-Robot shown in Fig.1 was developed. ¤. WEARABLE-AGRI-ROBOT A. Structure The Wearable-Agri-Robot has a total of ten joints (shoulders, elbows, hip joints, knees, and ankles). DC motors unit are installed in each of these joints, with the exception of the ankles [4]-[25]. The operation interface is attached to the exoskeleton on the left side. Because input operations are performed using the voice, the hands are free. The status of the operation is displayed on a monitor at the same height as T The 2009 IEEE/RSJ International Conference on Intelligent Robots and Systems October 11-15, 2009 St. Louis, USA 978-1-4244-3804-4/09/$25.00 ©2009 IEEE 5801 the line of vision. The controller and the battery for the motors are installed in the exoskeleton, achieving stand-alone operation. The frame of the Wearable-Agri-Robot is constructed from aluminum and acrylonitrile-butadiene-styrene resin, which is lightweight and excellent in rigidity in bending. Velcro and a buckle are used to attach the Wearable-Agri-Robot [1]-[3]. The gross weight of the Wearable-Agri-Robot is 30 kg. However, those who install it do not feel this weight because the Wearable-Agri-Robot rests on the ground. Because it has a structure where the upper-body is combined with the lower half of the body, the installation by one person is difficult, though it only requires about five minutes. A special stand was produced for taking it off. The tire places to the stand, and carrying to outdoor is easy. B. Control system Those who install it wear the inner wear that can be each joint angle detection. Angle sensors and giro sensors were used for the angle detection. Pressure sensors were used for the motor control of the lower half of the body. Hall sensors were used for the motor control of the upper-body. Two method are used to control the Wearable-Agri-Robot. One reads movement reading installation person's movement from the distance of Wearable-Agri-Robot and the joint angle of those who install it as those who install it and is a mode to follow as for the motor. The second method memorizes the movement pattern and then uses a mode to reproduce it. So as not to interfere with the wearer’s movement, the follow control is performed. When work is performed where there is predetermined movement pattern, control is performed using the pattern reproduction mode. The control is matched to the situation by switching between modes based on the work