In many robotic applications, high torque density and highly efficient actuators are required to handle the high torque motion without hampering mobility through excessive weight and footprint. Traditionally, engineers designing actuators for these types of applications use high-speed electrical motors in combination with high-ratio speed reducers such as harmonic and cycloid drives or lever arms in order to achieve the required torques. However, these systems are not ideal since they suffer from one or more of the following limitations: high cost, load hysteresis, nonlinear behavior, and torque ripple. An alternative to achieving the required torque increase is using an interesting type of compound planetary gear trains (C-PGTs). In this article, a novel type of such a C-PGT, based on the Wolfrom topology, is presented. An extra degree of freedom is created, which can be used to increase the performance of the overall gearbox, i.e., increase its efficiency, reduce its inertia, increase its torque capability, etc. This modified Wolfrom is discussed in detail by deriving a general framework for the design of such a transmission system. This framework consists of listing the specific fitting conditions for such a Wolfrom planetary gear train, the derivation of an efficiency model based on the Rolling Power concept, and a load analysis to determine the weakest gearing element. Finally, a prototype is built to demonstrate the design framework and the feasibility of the Wolfrom variant. Additionally, the trend of the efficiency model is confirmed.

中文翻译：

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一种用于机器人执行器的新型基于 Wolfrom 的齿轮箱

在许多机器人应用中，需要高扭矩密度和高效的执行器来处理高扭矩运动，而不会因过大的重量和占地面积而妨碍移动性。传统上，为这些类型的应用设计执行器的工程师将高速电动机与高比率减速器（例如谐波和摆线驱动器或杠杆臂）结合使用，以实现所需的扭矩。然而，这些系统并不理想，因为它们受到以下一个或多个限制：高成本、负载滞后、非线性行为和转矩脉动。实现所需扭矩增加的另一种方法是使用一种有趣的复合行星齿轮系 (C-PGT)。在本文中，介绍了一种基于 Wolfrom 拓扑的新型 C-PGT。创造了额外的自由度，可用于提高整个变速箱的性能，即提高其效率、降低其惯性、提高其扭矩能力等。通过推导通用框架来详细讨论此修改后的 Wolfrom用于设计这样的传输系统。该框架包括列出此类 Wolfrom 行星齿轮系的特定拟合条件，基于效率模型的推导滚动功率概念和负载分析，以确定最弱的齿轮元件。最后，构建了一个原型来演示 Wolfrom 变体的设计框架和可行性。此外，确认了效率模型的趋势。