Ren Jun, Shu Yikang, Lin Youwei
Hubei Key Laboratory of Modern Manufacturing Quantity Engineering, School of Mechanical Engineering, Hubei University of Technology, Wuhan 430068, China.
Micromachines (Basel). 2025 Apr 18;16(4):478. doi: 10.3390/mi16040478.
The workspace of the compliant parallel mechanism (CPM) is generally limited due to the small deformation range of flexible hinges, which are usually at the micro/nano scale. This paper takes the 2-DOFs -4R compliant parallel pointing mechanism (-4R CPPM) as the object and optimizes the workspace performance of the mechanism through redundant actuation, aiming to maximize the workspace. First, the kinetostatic model and the flexible hinge displacement model of the redundant actuated -4R CPPM are established, successively. The former model reveals the relationships between the output displacements and the input forces/displacements, while the latter relates the flexible hinge deformation and the input forces/displacements. Second, a space pointing trajectory is chosen to validate the accuracy of the kinetostatic model of the redundant actuated 3-4R CPPM through finite element (FE) simulation. The results show that the relative error between the analytical and the FE results does not exceed 2.1%, and the high consistency indicates the accuracy of the kinetostatic model. Finally, the workspace performance of the 3-4R and 4-4R CPPMs is successively optimized through redundant actuation. The results indicate that, compared with the non-redundant actuation case, the workspace can be effectively enlarged and become more symmetric by means of the redundant actuation. The maximum achievable pitch angle and the -direction motion range of the mobile platform both increase by 100%. Moreover, it is shown that the workspace in the non-redundant actuated case is a subset of the workspace in the redundant actuated case, and the position-workspace shape changes from planar to 3-D.
由于柔性铰链的变形范围通常处于微纳尺度，较小的变形范围使得柔顺并联机构（CPM）的工作空间一般受到限制。本文以二自由度-4R柔顺并联指向机构（-4R CPPM）为研究对象，通过冗余驱动优化该机构的工作空间性能，旨在使工作空间最大化。首先，依次建立了冗余驱动-4R CPPM的运动静力模型和柔性铰链位移模型。前者揭示了输出位移与输入力/位移之间的关系，而后者则建立了柔性铰链变形与输入力/位移之间的联系。其次，选择一条空间指向轨迹，通过有限元（FE）模拟来验证冗余驱动3-4R CPPM运动静力模型的准确性。结果表明，解析结果与有限元结果之间的相对误差不超过2.1%，高度一致性表明了运动静力模型的准确性。最后，通过冗余驱动依次优化了3-4R和4-4R CPPM的工作空间性能。结果表明，与非冗余驱动情况相比，通过冗余驱动可以有效地扩大工作空间并使其更加对称。移动平台的最大可达俯仰角和y方向运动范围均增加了100%。此外，结果表明非冗余驱动情况下的工作空间是冗余驱动情况下工作空间的一个子集，并且位置-工作空间形状从平面变为三维。
