This paper presents a developed manipulator and control method for automatic lapping process applied to a large work surface. A lapping machine consists of a newly designed parallelogram-type 5-axis manipulator and a conventional 3-axis gantry machine. The gantry machine is utilized to precision positioning over a large work area, and the manipulator is controlled by a separate controller for lapping operation in the local surface area which is provided by the CNC controller of gantry machine. The lapping process is, as a first step, needed to remove milling tool marks without injuring original shape, and then to correct the shape error. Wheel compliance becomes different in accordance with the special purpose such as tool mark removal and shape correction. Both processes require high stiffness of the manipulator. In this study, newly designed joints are adopted to secure the stiffness of the joints in both normal and lateral directions. Deadweight of manipulator including wheel motor as well as feed-forward torque control are adopted to suppress the vibration caused by abruptly dynamic cutting force. It was confirmed that the lapping operation was successful in wiping the curved contour without the structural vibration, and that the feed-forward torque control produces twice higher machining efficiency as well as 30% higher surface quality in comparison with the existing compliance control method. The experiment investigated the effects of the abrasive wheel compliance and the dynamic cutting force. In results, the smooth surface was achieved within a satisfied quality level of less than Rz 0.5 μm. It is considered that the proposed manipulator has great potential to be applied in unmanned lapping systems for a large work surface.

本文提出了一种适用于大型工作面的自动研磨工艺的机械手和控制方法。研磨机由新设计的平行四边形式5轴机械手和传统的3轴龙门机械组成。龙门机床用于在较大的工作区域上进行精确定位，并且机械手由单独的控制器进行控制，以在龙门机床的CNC控制器提供的局部表面上进行研磨操作。第一步，需要研磨工艺，以在不损害原始形状的情况下去除铣削刀具标记，然后校正形状误差。根据特殊目的（例如去除工具标记和形状校正），车轮柔度会有所不同。两种工艺都需要机械手的高刚度。在这个研究中，采用新设计的接头以确保接头在法向和横向方向上的刚度。机械手的自重，包括轮式电动机以及前馈转矩控制，可抑制突然的动态切削力引起的振动。已经证实，研磨操作成功地擦拭了弯曲轮廓而没有结构振动，并且与现有的顺应性控制方法相比，前馈扭矩控制产生了两倍高的加工效率以及30％的表面质量。实验研究了砂轮柔度和动态切削力的影响。结果，在小于Rz 0.5μm的满意质量水平内获得了光滑的表面。