Series and parallel elastic actuators offer complementary but mutually exclusive advantages, yet no existing actuator enables real-time transition between these topologies during operation. This paper presents a novel actuator design called the Dual-Topology Elastic Actuator (DTEA), which enables dynamic switching between SEA and PEA topologies during operation. A proof-of-concept prototype of the DTEA is developed to demonstrate the feasibility of the topology-switching mechanism. Experiments are conducted to evaluate the robustness and timing of the switching mechanism under operational conditions. The actuator successfully performed 324 topology-switching cycles under load without damage, demonstrating the robustness of the mechanism. The measured switching time between SEA and PEA modes is under 33.33 ms. Additional experiments are conducted to characterize the static stiffness and disturbance rejection performance in both SEA and PEA modes. Static stiffness tests show that the PEA mode is 1.53x stiffer than the SEA mode, with KSEA = 5.57 +/- 0.02 Nm/rad and KPEA = 8.54 +/- 0.02 Nm/rad. Disturbance rejection experiments show that the mean peak deflection in SEA mode is 2.26x larger than in PEA mode (5.2 deg vs. 2.3 deg), while the mean settling time is 3.45x longer (1380 ms vs. 400 ms). The observed behaviors are consistent with the known characteristics of conventional SEA and PEA actuators, validating the functionality of both modes in the DTEA actuator.

翻译：串联与并联弹性致动器具有互补但互斥的优势，然而现有致动器均无法在运行过程中实时切换这两种拓扑结构。本文提出一种名为双拓扑弹性致动器（DTEA）的新型致动器设计，可在运行过程中实现SEA与PEA拓扑的动态切换。通过开发DTEA的概念验证原型，证明了拓扑切换机制的可行性。实验评估了该机制在运行条件下的鲁棒性与切换时序。该致动器在负载下成功完成324次拓扑切换循环且无损伤，验证了机制的鲁棒性。SEA与PEA模式间的实测切换时间低于33.33毫秒。进一步实验表征了SEA与PEA模式下的静态刚度与抗扰动性能。静态刚度测试表明，PEA模式的刚度是SEA模式的1.53倍（KSEA = 5.57 ± 0.02 Nm/rad，KPEA = 8.54 ± 0.02 Nm/rad）。抗扰动实验显示，SEA模式下的平均峰值偏转是PEA模式的2.26倍（5.2° vs. 2.3°），平均稳定时间则长为3.45倍（1380 ms vs. 400 ms）。观测到的行为与传统SEA及PEA致动器的已知特性一致，验证了DTEA致动器两种模式的功能有效性。