Verification of Intelligent Planting Robot Arm Design Using Dynamics Analysis and Simulation Kee-Jin Park 1 *, Byeong-Soo Kim 1 and Jeong-Ho Yun 2

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1 2016 International Conference on Sustainable Energy, Environment and Information Engineering (SEEIE 2016) ISBN: Verification of Intelligent Planting Robot Arm Design Using Dynamics Analysis and Simulation Kee-Jin Park 1 *, Byeong-Soo Kim 1 and Jeong-Ho Yun 2 1 Machinery & Robot Research Division, Daegu Mechatronics & Materials Institute, Daegu, South Korea 2 Tokimec Korea Power Control Co., Ltd, Daegu, South Korea *Corresponding author Keywords: Planting, Intelligent robot, Dynamic analysis, Simulation. Abstract. In this study, it is our goal to perform multi-body dynamics analysis and simulation analysis for robot arm which is the key driving module for planting robot system in radioactive exposed area, and to develop optimal planting robot arm through maximum speed and thrust analysis of planting robot arm. For improved lightweight model, maximum driving thrust is found as 190N, and we intend to develop model that can maintain the operation and performance of planting robot arm while minimizing the linear actuator s load that occurs from initial model. Introduction In radioactive exposed area in Fukushima, Japan, radioactive decontamination procedure is performed by removing plants in the area, remove 5 cm depth of surface soil, clean the soil using high pressure washer, and then planting new plants in that area. Long term manpower and equipment are required to decontaminate the disaster area. However, it is hard to secure manpower due to the disaster characteristics, and it is required to develop new technology and equipment. There are various on-going studies for forest planting methods. Current planting method is done manually by persons who carry planting material on their back, climb up the mountain, and plant trees on the mountain. Manual work speed is planting 100 trees in 40 minutes (900 trees/day when work 6 hours/day). It is the purpose of this study to develop robot system that can plant trees in radioactive area which protects manpower from radioactive exposure, while increasing work efficiency more than 1.5 times[1]. Our purpose in this study are to perform multi-body dynamics analysis and simulation analysis for robot arm which is the key driving module for planting robot system in radioactive exposed area, and to develop optimal planting robot arm through maximum speed and thrust analysis of planting robot arm. Structure of Intelligent Planting Robot System The Basic structure of planting robot system consists of planting head unit which plants seedlings, protection cover insert unit which protects planted seedling, supply device that supplies planting tube and protection cover. These units and supply device are installed in one moving bogie. In addition, this bogie is designed to accommodate various control units, and batteries to drive electric/ electronic equipment. Figure 1 shows the conceptual diagram for the whole structure of planting robot system[2]. 475

2 Figure 1. This conceptual diagram of intelligent planting robot system. Dynamic Analysis and Simulation for Planting Robot Arm Planting robot s planting arm (initial model) is composed of base frame which supports total arm by fixing to planting robot moving bogie, two link arm, linear actuator which drives arm, and end effector which holds and plants trees. Table 1 shows the definition of driver part of planting robot arm to perform linear actuator related dynamics analysis. Total arm weight is 61.4kg, and we used maximum operation range and maximum speed of operation as its analysis criteria. Recurdyn V8R1 is used to analyze dynamics of planting robot. We called 3-dimension designed modeling files, perform model simplification for each part module, and then defined material property[3,4]. Figure 2. Initial model mechanism diagram of planting robot. Planting robot arm has two link arm structure for smooth planting work. Link arm 1 is driven in connection with linear actuator 1 which is mounted at the bottom side. Link arm 2 is jointed with linear actuator 2, and performs 2 degree of freedom movement in the space. Figure 3 shows the results of dynamics analysis for planting robot arm initial model. It was found that linear actuator 1 and linear actuator 2 requires maximum driving thrust of 570.1N and 509N, respectively. For initial 476

3 model, relatively more driving thrust is required at starting point and end point, and this can be reduced through weight reduction and design change of link arm 2 structure[5]. Table 1. Dynamics analysis criteria for planting robot arm initial model. Item Load Remark Base frame 20kg Fix to main body Link arm kg - Link arm 2 8kg - End effector 1.9kg Rotate 180 to counter-clock direction Linear actuator 1 5.2kg Stroke : 150mm, Velocity : 12mm/sec Linear actuator 2 3.5kg Stroke : 300mm, Velocity : 70mm/sec Load total 61.4kg Figure 3. Dynamics analysis results for planting robot arm initial model (maximum thrust). Figure 4 shows improved model that minimizes linear actuator s load which occurs at the initial model of planting robot arm, while reducing the weight of total weight of planting robot arm. Improved planting arm model has same structure in base frame which supports total arm, link arm, linear actuator which drives arm and End effector which holds and plants trees. Changed part is added rotating motor that drives link arm 2. Especially, linear actuator 1, 2 operates link arm 1 at the same time to lower the load, and its design is able to drive in right-left direction of arm when linear actuator 1 and 2 operate in opposite direction. Table 2 shows the driving part definition for dynamics analysis of improved planting robot arm model. Its total arm weight is 30.4 kg, which is more than 50% reduced weight compare to initial model. 477

4 Figure 4. Improved model of planting robot arm block diagram. Table 2. Dynamics analysis criteria for planting robot arm improved model. Item Load Remarks Base frame 14.8kg link 3 point support Link arm 1 8.3kg Connect to Linear actuator 1,2 Link arm 2 2.3kg Direct connection with motor End effector 0.6kg 180 Counter-clock rotation Linear actuator 1 2.2kg Velocity : 19.7mm/sec, stroke : 20mm Linear actuator 2 2.2kg Velocity : 19.7mm/sec, stroke : -20mm Load total 30.4kg Figure 5 shows the dynamics analysis results for planting robot arm improved model. According to analysis results, maximum driving thrust of linear actuator 1,2 are 190N and 176N, respectively. Also, it was found from simulation results that plant robot arm s end_effector can rotate left-right direction in 12.8, when line actuator 1,2 move straight movement of 20mm, -20mm, respectively. Figure 5. Dynamics analysis results for plant robot arm improved model (Maximum thrust). 478

5 Summary (1) We performed multi-body dynamics analysis and simulation analysis for robot arm, which is the key driving module of planting robot system, for design optimization, (2) According to dynamics analysis result, relatively more driving thrust is required at starting point and end point for initial model of planting robot arm, and this can be reduced through weight reduction and structure design change in improved model. (3) Planting robot arm s improved model can reduce more than 50% of the initial model s weight, and it is expected to reduce more than 65% of maximum driving thrust. Acknowledgments This research is funded by a robot industry cluster business project of the Ministry of Trade, Industry and Energy, "Development of Intelligent Planting Robot for recover Radioactive Damaged Area" References [1] Agricultural Robots Market Share, Market Strategies and Market Forecast, 2014 to 2020, Wintergreen Research (2014). [2] K.J. Park, S.S. Ahn and J.M. Cho, Development of the intelligent planting robot system for disaster restoration, Proc. of the Korean Society for Precision Engineering Spring Conference, 2015, pp.411. [3] H. S. Kim, Flexible Multibody Dynamic Analysis using Experimental Modal Analysis, Transactions of Korea Society of automotive engineers, V. 2, [4] B.S. Kim, K.J. Park and J.M. Cho, Design Verification of the Intelligent Planting Robot using Multi body Dynamic Analysis, Proc. of the Society of CAD/CAM Engineers Conference, 2015, pp [5] J. M. Kang, J.H. Choi, Load Evaluation Method for FEA through the simulation of Multi-body Dynamics, Proc of the Korean Society of Mechanical Engineers, 2014, Vol. 14, pp