In this paper, two new parallel mechanisms (PMs) with fewer active inputs than the degrees of freedom (DOFs)are proposed: (i) an nSPS (n = 7, 8, 9) six-DOF PM with n-6 active inputs and six lockable joints. and (ii) a 3RPS-SPS 3-DOF PM with one active input and three lockable joints. Compared with the traditional PMs, the difference is that the proposed PMs can achieve the same mobility by using a minimal number of active joints. Moreover, the load-carrying capacity is also improved compared with the original standard mechanisms, since the new PMs become statically redundant when all the branches are locked. For this purpose, a sequential motion control principle is introduced that requires both inverse and forward kinematics of PMs. Kinematic modeling, dimensional optimization, and structural design are carried out for the 7SPS and 3RPS-SPS mechanisms, and the two prototypes are constructed for experimental validation. Both simulation and experiment results have shown that the proposed hybrid PM can achieve the original mobility while significantly reducing the number of actuators.

中文翻译：

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主动输入少于自由度的新型并联机构的设计与运动原理分析

在本文中，提出了两种新的并联机构（PM），其主动输入少于自由度（DOF）：（i）n个SPS（n  = 7,8,9）六自由度PM，具有n -6个主动输入输入和六个可锁定接头。(ii) 具有一个主动输入和三个可锁定关节的 3RPS-SPS 3-DOF PM。与传统的永磁体相比，不同之处在于所提出的永磁体可以通过使用最少数量的活动关节来实现相同的移动性。此外，与原来的标准机制相比，承载能力也得到了提高，因为当所有分支都被锁定时，新的 PM 变得静态冗余。为此，引入了顺序运动控制原理，该原理需要永磁体的逆运动学和正运动学。对7SPS和3RPS-SPS机构进行了运动学建模、尺寸优化和结构设计，并构建了两个样机进行实验验证。仿真和实验结果都表明，所提出的混合永磁体可以实现原始的移动性，同时显着减少执行器的数量。