Application of a chatic stimulation to development of a chair free from backache

飞机、铁路、汽车等交通工具用于长途运输。在运输过程中，特别是在飞机上，乘客被迫具有收紧的姿势。因此，乘客将受到身体肌肉的痛苦压力。人体内的生理压力有时会对健康造成严重危害。为了释放肌肉上的压力，最近，引入了具有指压治疗设施的放松机。在治疗过程中，人体受到拳头的敲击可以获得一种放松的状态，本研究给出了人体受到周期性和混沌敲击刺激时的生物信号分析结果。测量身体皮肤上的电信号。从身体的胸部检测心电图（ECG）。肌电图（EMG）的信号从双臂的肌肉测量。计算测试信号的最大李雅普诺夫指数。利用Karhuen-Loeve变换（主成分分析），阐明了外界刺激对人体信号的贡献。当快速的周期性敲击施加到身体时，心脏的心跳增加到更高的频率。当人体受到敲击机的快速敲击时，肌电信号的最大李雅普诺夫指数比慢速敲击状态和安静状态下的肌电信号的最大李雅普诺夫指数降低。对肌电信号有贡献的物理参数的数量减少。结果表明，快速激励力作用于物体，会产生自由度较低的稳态周期响应.在安静、周期性敲击和混沌激励三种测试条件下，心电信号比肌电信号表现出更为复杂的非稳态响应.通过实验验证，发现对人体的舒适性刺激是混沌刺激。

Vehicles such as airplane, railway and automobile are used for a long distance transportation. During the transportation, passenger is enforced to have a tightened posture especially in the airplane. Therefore, passenger will be affected to a painful stress in muscles of the body. Physical stress in the human body sometimes will happen to be serious hazard to health. To release the stress on the muscle, recently, relaxation machine is introduced with facility of a finger pressure therapy. In the therapy, the body can get a relaxed condition knocked by a fist.This study presents the results of biological signal analysis in human body subjected to periodic and chaotic knocked-stimulation. Electrical signals on a skin of the body are measured. An electricalcardiogram(ECG) is detected from a chest of the body. The signal of an electromyogram (EMG) is measured from muscles of both arms. The maximum Lyapunov exponent is calculated for the signal under test. Using the Karhuen-Loeve transformation (Principal Component Analysis), contributions to the signal of the body under the external stimulation are clarified.It is found that the followings ;1. When the quick periodic knocking is applied to the body, cardiac beat of the heart increases to higher frequency.2. When the body is stricken quickly by the knocking machine, the maximum Lyapunov exponent of the EMG decreases to lower value compared to those of slow knocking condition and the quiet condition. The number of physical parameter contributed to the EMG decreases. It shows that the quick stimulated forces to the body will produce a steady-state periodic response with lower degree of freedom.3. Under three testings of quiet condition, periodic knocking and chaotic excitation, the signals of the ECG show more complex unsteady behavior than that of the responses of EMG.4. Comfortable excitation to the body is found to be the chaotic stimulation by the test in our experiment.