Design of kinematically-redundant two-module robots

当需要精确定位时（如在机床或对准工作台中），并联机器人由于其高刚性而成为首选。然而，并联机器人的主要缺点之一是它们的工作空间相对较小，这进一步受到所谓的2型奇点的限制。当并联机器人接近2型奇异配置时，其末端执行器承受载荷的能力显着受损。由于这些独特性，很少有公司能够想出创新的设计，大多数公司坚持流行的六足，这往往是过度设计（例如，太大了）对于手头的应用程序。 分而同的策略是有希望实现负担得起的高精度机器人系统。代替设计单个n自由度（n-DOF）并联机器人，申请人将选择使用两个单独的机器人，一个具有i个DOF，旨在操纵工具（可能是串联机器人），另一个具有j个DOF，用于保持工件。此外，该双模块机器人系统将是运动学冗余的，这意味着i和j的和将大于n。 所提出的研究计划背后的主要思想是使用具有一个或两个运动冗余度的两个机器人（其中至少一个是平行的）的组合，即，i + j = n + 1或i + j = n + 2，以便完全消除奇异性问题。因此，所提出的方案的第一个目标是开发一个系统的方法，用于分析几何条件，导致运动冗余设计与大的工作空间和奇异流形的减少的维度。特别注意将支付给低流动性空间并联机构与混合自由度，这已被证明是一个很好的选择机床。第二个目标是为现有的串联和并联机器人设计辅助模块。最后，第三个目标将是开发新的低成本自动校准技术，这些两个模块的机器人。

When precise positioning is needed (as in a machine tool, or in an alignment table), parallel robots are a choice of predilection due to their high rigidity. However, one of the major disadvantages of parallel robots is their relatively small workspace, which is further limited by the presence of so-called Type 2 singularities. When a parallel robot is close to a Type 2 singular configuration, its ability to withstand loads with its end-effector is significantly compromised. Because of these singularities, very few companies have managed to come up with innovative designs and most stick to the popular hexapod, which is often overdesigned (e.g., too big) for the application at hand. The divide-and-concur strategy is promising for achieving affordable high-accuracy robot systems. Instead of designing a single n-degree-of-freedom (n-DOF) parallel robot, the applicant would opt for the use of two separate robots, one with i DOFs aimed at manipulating the tool (possibly being a serial robot) and another with j DOFs for holding the workpiece. Furthermore, this two-module robot system will be kinematically redundant, which means that the sum of i and j will be greater than n. The main idea behind the proposed research program is to use a combination of two robots (at least one of which is parallel) with one or two degrees of kinematic redundancy, i.e., i + j = n + 1 or i + j = n + 2, in order to completely eliminate problems with singularities. The first objective of the proposed program is therefore to develop a systematic approach for analysing the geometric conditions leading to kinematically redundant designs with large workspace and singularity manifolds of reduced dimension. Particular attention will be paid to lower-mobility spatial parallel mechanisms with mixed DOFs, which have proven to be an excellent choice for machine tools. The second objective will be designing secondary modules for existing serial and parallel robots. Finally, the third objective will be the development of novel low-cost automated calibration techniques for these two-module robots.