基于Burmester理论的微耕机挡土板导引机构设计

Design of soil-blocking plate guide mechanism of micro-cultivator based on Burmester theory

为解决微耕机刀轴缠草难以清理的问题,提出一种微耕机可动挡土板的设计方案,并基于Burmester理论对其导引机构的设计方法进行研究。首先,根据现有微耕机尺寸确定可动挡土板在运动轨迹上的4个位置;其次,利用镜极4R机构旋转法求出Burmester圆点曲线及相应的圆心曲线;再次,通过几何法确定驱动杆的安装位置并对其分支缺陷进行甄别;最后,基于区域类型图法进行了4R机构及其驱动杆的优选。研究结果表明:所提出的微耕机可动挡土板的设计方案是可行的,挡土板可在需要清理缠草的时候按预定轨迹抬起从而避免运动干涉;所提出的区域类型图方法可有效剔除解域中的驱动缺陷解和运动学缺陷解,从而大幅提升可行机构解的搜索效率。本研究同样适于农机设计中的其他刚体导引问题。

In order to solve the problem of the difficulty in cleaning up the grass wrapped around the rotary blade of the micro-cultivator,a design scheme for a movable soil-blocking plate for the micro-cultivator is proposed.The design method of its guiding mechanism is studied based on Burmester theory.Firstly,the four positions of the movable soil-blocking plate on the motion track are determined according to the size of the micro-cultivator.Secondly,the Burmester circle curve and the corresponding center curve are obtained though the motion analysis of mirror pole 4R linkage.Thirdly,the installation position of the driving rod is determined by geometric method,and its branch defects are identified.Finally,the 4R linkage and its driving rod are optimized based on the regional type map method.The results show that the design scheme of the movable soil-blocking plate of the micro-cultivator is feasible.The soil-blocking plate can be lifted according to the predetermined track when it is necessary to clean the entangled weeds without structural interference.The proposed regional type map method can effectively eliminate the driving defect solutions and kinematic defect solutions in the solution domain,thus greatly improving the search efficiency of feasible mechanism solutions.This study is also applicable to other rigid body guidance problems in agricultural machinery design.