| Summary: | 碩士 === 國立成功大學 === 機械工程學系碩博士班 === 94 === Stroke and spinal cord injury frequently lead to the disconnection between central nervous system and muscles. Patients lose the ability of muscle control and cannot exercise on their will. Brain-computer interface (BCI) is one of the important technologies in neural engineering to help patients recover communication between their mind and environment. In a BCI system, orthotic devices are necessary either to enhance the weak muscles or to provide biofeedback to improve performance of the man-machine system.
An active orthotic hand with two degrees of freedom was developed in this thesis. Its main body was made of polypropylene and the actuator is a light-weight RC servo motor. For better control, two types of logic controls, namely, on-off and finite state controls are implemented for users with different EEG detection rate.
Besides, a mechanical stimulator was set on the orthotic hand and it stimulates the subject’s palm to enhance the event-related desynchronization of m wave by using the principle of stochastic resonance. Finally, clinical trials on seven normal subjects were performed to investigate the factors, namely, right or left hand imaginary task and wearing of orthotic hand which affect the success rate of orthosis operation. The result analyzed by two-way ANOVA indicates that right or left imaginary may affect the EEG detection rate and the average EEG detection rate of the non-habitual-handed imagination is higher than those of habitual-handed about 11.3% under a level of 0.1. Although wearing of orthotic hand has no statistical meaning in ANOVA analysis, its average EEG detection rate is higher than those of orthotic hand free about 6.2%.
Compared with previous work, the new orthotic hand has two advantages: light weight and low disturbance to EEG acquisition although the average success rate of operation was low. Further study on combining b wave and biofeedback training might improve the success rate.
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