A six degrees-of-freedom parallel platform in a 6-RR-RP-RR configuration with high accuracy, high stiffness and a large working stroke is studied for application to the sub-mirror adjustment system of a large-aperture telescope. To meet the performance requirements, the parallel platform adopts a self-centering and well-designed offset universal hinge. The two hinge axes of the offset hinge do not intersect but have a specific offset in space, which makes the kinematics more complex than that with a common universal hinge. Therefore, to solve this complex kinematics problem, this paper innovatively introduces the Denavit–Hartenberg (D-H) parameter method that is used for series mechanisms. The method has a simple modeling process, strong applicability and continuity, providing a new tool for the analysis and application of the parallel mechanisms. A kinematics model of the parallel platform can be constructed and solved using a numerical iteration method. The accuracy of the numerical kinematics solution is verified using a co-simulation method. This paper analyses the passive derivative motion and the leg length error is compensated. Finally, test studies of the motion resolution, the repetitive positioning accuracy, the motion stroke, the static stiffness of the legs, and the static stiffness and dynamic stiffness of the entire machine were also carried out to verify the platform’s performance.

6-RR- RP中的六自由度并行平台研究了具有高精确度，高刚度和大工作行程的-RR配置，以将其应用于大口径望远镜的副镜调节系统。为了满足性能要求，平行平台采用了自动定心和精心设计的偏置式通用铰链。偏置铰链的两个铰链轴不相交，但在空间上具有特定的偏置，这使得运动学比普通通用铰链更复杂。因此，为解决这一复杂的运动学问题，本文创新地介绍了用于串联机构的Denavit-Hartenberg（DH）参数方法。该方法建模过程简单，适用性和连续性强，为并行机制的分析和应用提供了新的工具。可以使用数值迭代方法构建和求解并行平台的运动学模型。使用协同仿真方法验证了数值运动学解决方案的准确性。本文分析了被动微分运动并补偿了腿长误差。最后，还对运动分辨率，重复定位精度，运动行程，腿部的静态刚度以及整个机器的静态刚度和动态刚度进行了测试研究，以验证平台的性能。