Patient-Driven Command Control Strategy for the Hemiplegia to Restore Hand Function Using Electrical Stimulation
| Autor: | Ying-Han Chiou, 邱盈翰 |
|---|---|
| Rok vydání: | 2005 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 93 Functional electrical stimulation (FES) is one of a number of methods utilized in developed assistive devices to restore patients’ lost hand functions. Some important issues about a FES system to restore hand functions have been addressed and investigated in this dissertation, including the control strategies of the system, standard procedures of finding the stimulation sites, the input sources for a FES system, and the man-machine interface designed for the clinical users. For quadriplegics, the input sources or the command controller of assistive devices are inconvenient or complicated to use. With the control strategy of patient-driven loop, they can use their residual capabilities to control these devices, such as the myoelectric signals generated from the muscles. In addition, if there is an optimal control strategy built in the controller of FES system, patients will benefit much from it. Due to the problem that quadriplegics are encumbered with the complicacy or inconvenience of the input sources and the controller commands, we have proposed the optimal strategy for FES system, including the standard procedures for finding the stimulation sites, patients’ selection, and residual capabilities for patient-driven control. This proposed concept and strategy would be useful for patients utilizing a FES system and, in addition, can be modified or applied to different rehabilitation applications. Electromyographic (EMG) signals have been chosen as in put sources to control the system since they are highly common and acceptable signals. However, there is a need to determine the differences of recognition rates and EMG recordings between using active and passive electrodes. Experimental results show that the estimated recognition rates in the passive electrodes are comparable to those in the active ones (averaged recognition rate, 88.5% vs. 85.84% in the autoregressive coefficients, and 84.84% vs. 83.5%, in the cepstral coefficients, respectively). From these findings, a four-channel recording system with the active electrode was designed for detecting EMG signals. Connecting this device with a FES system, the myoelectric signal will be able to serve both as the trigger for the system and as the adjustment of the electrical stimulation parameters to improve system performance. In addition to the recording system, a versatile LabVIEW-based toolbox was also designed for the proposed system. This toolbox can assist clinical researchers (such as the physicians or physical therapists) tune parameters such as waveform types, current intensity, stimulation time, etc, in the proposed system to provide suitable electrical stimulation. The described man-machine interface can also be implemented in other applications. From the results of the control strategy in FES system to restore hand functions, the subjects can use generate suitable control signals for the system so that the muscles will be properly excited by electrical stimulation. Moreover, in the viewpoints of rehabilitation and psychology, there is noticeable benefit from using their residual capabilities to control FES systems. It is believed that patient-driven loop as well as the discussions of optimal control strategy in this dissertation can provide suitable control to FES systems. This is very useful not only for the hand function restoration by electrical stimulation, but also for the control of other assistive devices. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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