School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China.
Huashan Hospital, Fudan University, Shanghai, China.
Proc Inst Mech Eng H. 2020 Oct;234(10):1070-1082. doi: 10.1177/0954411920938902. Epub 2020 Jul 10.
An in vitro simulation test using a designed well-targeted test rig has been regarded as an effective way to understand the kinematics and dynamics of the foot and ankle complex in the dynamic stance phase, and it also allows alterations in both internal and external control compared to in vivo tests. However, current simulators are limited by some assumptions. In this study, a novel foot and ankle bionic dynamic simulator was developed and validated. A movable 6-degree-of-freedom parallel mechanism, known as Steward platform, was used as the core structure to drive the tibia, with a tibial force actuator applied with different loads. Four major muscle groups were actuated by four sensored pulling cables connected to muscle tendons. Simulation processes were controlled using a software developed based on a proportional-integral-derivative control loop, with tension-compression sensors mounted on tendon pulling cables and used as real-time monitor signals. An iterative learning module for tibial force control was integrated into the control software. Six specimens of the cadaveric foot-ankle were used to validate the simulator. The stance phase was successfully simulated within 5 s, and the tibia loads were applied based on the body weight of the cadaveric specimen donors. Typical three-dimensional ground reaction forces were successfully reproduced. The coefficient of multiple correlation analysis demonstrated good repeatability of the dynamic simulator for the ground reaction force (coefficient of multiple correlation > 0.89) and the range of ankle motion (coefficient of multiple correlation > 0.87 with only one exception). The simulated ranges of the foot-ankle joint rotation in stance were consistent with in vivo measurements, indicating the success of the dynamic simulation process. The proposed dynamic simulator can enhance the understanding of the mechanism of the foot-ankle movement, related injury prevention, and surgical intervention.
一种使用设计好的针对性测试装置的体外模拟测试被认为是理解动态站立阶段足踝复合体运动学和动力学的有效方法，与体内测试相比，它还可以改变内部和外部控制。然而，目前的模拟器受到一些假设的限制。本研究开发并验证了一种新型的足踝仿生动态模拟器。一个可移动的 6 自由度并联机构，称为 Stewart 平台，作为核心结构来驱动胫骨，胫骨力致动器施加不同的负载。四个带有传感器的牵拉电缆连接到肌腱上，以驱动四个主要的肌肉群。模拟过程由基于比例积分微分控制环的软件控制，张力-压缩传感器安装在牵拉电缆上，作为实时监测信号。胫骨力控制的迭代学习模块被集成到控制软件中。六个尸体足踝标本用于验证模拟器。在 5s 内成功模拟了站立阶段，并且根据尸体标本供体的体重施加了胫骨载荷。成功再现了典型的三维地面反力。多相关系数分析表明，动态模拟器对地面反力（多相关系数>0.89）和踝关节运动范围（多相关系数>0.87，只有一个例外）具有良好的重复性。站立时足踝关节旋转的模拟范围与体内测量一致，表明动态模拟过程的成功。所提出的动态模拟器可以增强对足踝运动机制、相关损伤预防和手术干预的理解。
