Control of FES and an Electric Motor Drive for a hybrid gait neuroprosthesis

 描述(申请人提供)：功能性电刺激(FES)和动力外骨骼是一些旨在恢复截瘫患者行走的技术之一。FES可以通过外部施加低水平的重复电流来获得所需的腿部肌肉收缩。动力外骨骼使用电动马达驱动来移动腿部关节。单独而言，每一种都有局限性。我们的目标是将这两种技术结合起来，创造出一种混合型神经假体，它比基于FES的步行系统或仅有动力外骨骼更具优势。由于提高了扭矩可靠性，混合式步行矫形器可以使用更长的时间或更长的距离。此外，在混合型神经假体中使用FES可能会提供与其使用相关的治疗益处。具体地说，我们建议设计和评估一种用于混合式步行神经假体的新型自动控制器，该控制器由FES系统和半动力外骨骼组成。对于混合式步行神经假体的控制方法的设计和评估的研究很少。然而，对其控制方法的研究对于保证其运行效率、步态稳定性和扭矩可靠性具有重要意义。在我们的初步结果中，我们表明，尽管存在上述挑战，基于模型预测控制的动态控制分配可以同时控制FES和电机产生伸膝任务。我们还表明，新的控制器能够适应股四头肌的肌肉疲劳，并能够维持更长时间的膝关节伸展运动。该提案的假设是，与单一的FES系统相比，新控制器可以在更长的时间内维持肢体运动，并且总体功率要求将低于电动马达系统。该提案的具体目标是：(1)物理验证模型预测控制(MPC)方法，该方法优化改进型混合腿部伸展机器中FES和电机的扭矩贡献；以及(2)在混合行走设备上物理验证MPC方法，以诱导脊髓损伤患者行走。拟议中的项目如果成功，将带来一种混合行走矫形器，它将更轻，可以使用更长的时间或更长的距离。此外，在混合型神经假体中使用FES将提供治疗益处；例如，应用电刺激可以改善心血管健康，增加肌肉质量和抗疲劳能力。

 DESCRIPTION (provided by applicant): Functional electrical stimulation (FES) and a powered exoskeleton are among some of the technologies that aim to restore walking in individuals with paraplegia. FES can be used to obtain desired muscle contractions in the lower limbs through external application of low-level repetitive electrical currents. A powered exoskeleton uses electric motor drives to move the lower-limb joints. Alone, each has limitations. We aim to combine these two technologies to create a hybrid neuroprosthesis that is more advantageous than an FES-based walking system or a powered exoskeleton alone. Because of improved torque reliability, the hybrid walking orthosis can be used for a longer time or over longer distances. Moreover, the use of FES in the hybrid neuroprosthesis may provide therapeutic benefits associated with its use. Specifically, we propose to design and evaluate a new automatic controller for a hybrid walking neuroprosthesis that is composed of an FES system and a semi- powered exoskeleton. Little research has gone into the design and evaluation of control methods for a hybrid walking neuroprosthesis. However, research on its control methods is important for ensuring operational efficiency, gait stability, and torque reliability. In our preliminary results, we show that a model predictive control-based dynamic control allocation can simultaneously control FES and an electric motor to produce a knee extension task, despite the aforementioned challenges. We also show that the new controller can adapt to muscle fatigue in the quadriceps muscle and can sustain knee extension movements for a longer period of time. The proposal's hypothesis is that the new controller can sustain limb movements for a longer period of time compared to a sole FES system and the overall power requirement will be lower than an electric motor system. The specific aims of the proposal are: (1) To physically validate the model predictive control (MPC) method that optimizes the torque contribution from FES and an electric motor in a modified hybrid leg extension machine; and (2) To physically validate the MPC method on a hybrid walking device to elicit walking in persons with spinal cord injury. The proposed project, if successful, will lead to a hybrid walking orthosis that will be lighter and can be used for a longer time or over longer distances. Moreover, the use of FES in the hybrid neuroprosthesis will provide therapeutic benefits; e.g., application of electrical stimulation improved cardiovascular fitness and increased muscle mass and fatigue resistance.