Design and fabrication of the manual-rice-transplanter, and its linkage synthesis and analysis

Abstract

A general design procedure was illustrated through this project by designing and fabricating a manually operated rice-transplater. The basic system of the new design was adopted from the existing one designed by IEAU. But newly invented are a six-revolute-pair-mechanism for planting seedlings and an intermittand feeding mechanism for feeding seedlings. The linkages of a four-lever-crank mechanism for planting seedlings adopted in the original IEAU unit were analysed grafically as well as analytically. Synthesis of the new mechanism was done by the trial-and-error method graphically. The analysis of the new six-link-crank mechanism was done with a combined method of the independent-position-equations and the graphical method. The non-uniform input torque due to the dynamic force of the coupler link of the four-lever-crank mechanism was cause a large portion of the required driving power of the transplanter. To get a new mechanism which would satisfy all the constraints and all the requirements in the problem definition, synthesis of the new six-revolute-pair mechanism was carried out analytically by the displacement matrix method. The analysis involved the concept of matrix loop equations with the linear transformation matrix which had been derived from the D-H kinematic notation. The static torque was determined analytically by combining the concept of virtual work with matrix loop equations to relate virtual deformation to the force of an output link. The solution of non-linear synthesis equations and manipulation of matrix loop equations was obtained by a computer. As a floater, which support the weight of the transplanter in wet field, friction between the floater and soil requires another significant portion of the operating power. An analysis of the friction was given in detail by a coworker, Y.D.Choi(15). The irregular dynamic forces and average friction forces occurred while the machine is in operation were measured with strain gages. A special link betw...