Department of Mechanical and Industrial Engineering, University of Massachusetts, Amherst, Massachusetts, USA.
FTL Labs Corp., Amherst, Massachusetts, USA.
Int J Numer Method Biomed Eng. 2020 May;36(5):e3334. doi: 10.1002/cnm.3334. Epub 2020 Mar 23.
Simulation of musculoskeletal systems using dynamic optimization is a powerful approach for studying the biomechanics of human movements and can be applied to human-robot interactions. The simulation results of human movements augmented by robotic devices may be used to evaluate and optimize the device design and controller. However, simulations are limited by the accuracy of the models which are usually simplified for computation efficiency. Typically, the powered robotic devices are often modeled as massless, ideal torque actuators that is without mass and internal dynamics, which may have significant impacts on the simulation results. This article investigates the effects of including the mass and internal dynamics of the device in simulations of assisted human movement. The device actuator was modeled in various ways with different detail levels. Dynamic optimization was used to find the muscle activations and actuator commands in motion tracking and predictive simulations. The results showed that while the effects of device mass and inertia can be small, the electrical dynamics of the motor can significantly impact the results. This outcome suggests the importance of using an accurate actuator model in simulations of human movement augmented by assistive devices. NOVELTY: Demonstrating the effects of including mass and internal dynamics of the actuator in simulations of assisted human movement A new OpenSim electric motor actuator class to capture the electromechanical dynamics for use in simulation of human movement assisted by powered robotic devices.
使用动态优化模拟肌肉骨骼系统是研究人体运动生物力学的一种强大方法，并且可以应用于人机交互。通过机器人设备增强的人体运动的模拟结果可用于评估和优化设备设计和控制器。然而，模拟受到模型准确性的限制，这些模型通常为了提高计算效率而被简化。通常，动力机器人设备通常被建模为无质量、理想扭矩执行器，即没有质量和内部动态，这可能对模拟结果产生重大影响。本文研究了在辅助人体运动的模拟中包括设备质量和内部动态的效果。设备执行器以不同的详细程度以各种方式建模。在运动跟踪和预测模拟中，使用动态优化来找到肌肉激活和执行器命令。结果表明，尽管设备质量和惯性的影响可能很小，但电机的电气动态会显著影响结果。这一结果表明，在使用辅助设备增强的人体运动模拟中使用准确的执行器模型的重要性。新颖性：演示在辅助人体运动的模拟中包括执行器的质量和内部动态的效果。一种新的 OpenSim 电动马达执行器类，用于捕获机电动力学，用于模拟由动力机器人设备辅助的人体运动。
