起重机主梁腹板变形自动矫正执行器设计

起重机主梁生产线中下盖板与形梁组对时,用人工矫正方法矫正腹板波浪变形会在主梁腹板上留下焊疤,并增加没有附加值的打磨操作。为了改善这一状况,并高效配合机器人实施定位焊,采用磁力吸附原理进行腹板变形的自动矫正。首先对形梁腹板变形进行测量,并拟合出变形曲线,不同格子间的变形均为凹变形,最大变形值为24mm。接着利用有限元方法分析了磁铁布置方式对矫正效果的影响:在同样的磁铁吸附应力和布置方式下,大筋板间的间距越大,矫正效果越明显;而在同样的大筋板间距下,初始凹变形小有利于矫正;对所有的格子间,永磁铁距腹板下边缘越近,矫正效果越明显,同样的磁铁(长宽比大于1),横放比竖放的矫正效果明显。最后研发了自动矫正执行器的物理样机,其由吸附单元、推拉单元、结构单元、传感单元和控制单元组成,并进行了现场试验,测试结果满足矫正工艺的精度要求(±2mm),同时也验证了有限元分析结果的准确性。主梁腹板变形自动矫正执行器的研制实现了腹板变形识别、腹板临时连接的建立、矫正过程力感知和矫正运动可控。该装置实现了机器人定位焊前的腹板变形自动矫正,对前道工序的焊接工艺优化具有一定意义。

Design of automatic rectification effector for deformation of crane girder web

When the bottom plate and the Π-beam are assembled in the crane major beam production line, the manual rectification process will produce scars on the girder web that need additional polishing operation.In order to improve the condition and cooperate with the robot to deal with the tack weld, the method of magnetic adsorption was used to realize the automatic rectification for the girder web deformation.Firstly, the deformation of the girder web was measured, and the deformation curves were fitted.All deformations were concave, and the max value was 24 mm.Secondly, the effect of the layout of the magnet was analyzed by the finite element method.Under the same magnetic adsorption stress and the same magnet layout, the larger the span between the big rib plates were, the better the rectification effect became.And under the same span between the big rib plates, the small initial deformation was beneficial to rectify.To all grid space, the nearer the distance from the lower edge of the girder web was, the better the rectification effect became.The horizontal layout was beneficial to rectify as compared with the vertical layout to the same magnet (the ratio of the length and the width was greater than 1).Finally, the physical prototype of automatic rectification effector was developed, which consisted adsorption unit, push-pull unit, structure unit, sensing unit and control unit, and the field testing was carried out.And the results of the testing were satisfied with the accuracy requirement(±2 mm) of the rectification process.Moreover, the results of the testing also verified the conclusion of the finite element analysis.As a conclusion, the development of the automatic rectification effector realizes the identification of the deformation of the girder web and the temporary establishment with the girder web, the force perception in the rectification process and the control to the rectification motion.The device realizes the automatic rectification of the web deformation before the robot positioning welding, which is of great significance to optimization of welding technology of the previous process.