并联机构外文资料，parallel mechanisms (PMs) have attracted a lot of attention from the academic and industrial communities. Compared with the more commonly used serial robots, the parallel one has attractive advantages in accuracy, rigidity, capacity, and load-to-weight ratio. The PMs have been and are being used in a wide variety of applications such as motion simulators, parallel manipulators, nanomanipulators, and micro-manipulators. In recent years, the research and application have evolved from general six-DOF PMs to lower-mobility PMs. The essential reason is that lower-mobility PMs have similar applications to general six-DOF PMs, while they are much simpler in structure and cheaper in cost. The research of lower-mobility PMs has become new hot point. A great deal of research on lowermobility PM has been carried out all over the world, and a large number of new mechanisms, such as Delta, Tricept, and medical robots, have been built for various applications.