A Sensing Insole for Measuring Plantar Pressure Distribution
|Keywords||PVDF sensor sensor chip structure biomechanics of human foot plantar pressure distribution|
The characteristic of plantar pressure distribution is one of the important parts to reveal the regularity of gait. Testing and analysis of human gait provided important theoretical basis for the biomechanics, rehabilitation medicine, orthopedic surgery, sports training and the footwear industry. Since the 20th century, a variety of methods for measuring plantar pressure continue to emerge, measuring and testing technique continue to improve, and gradually developed into the wearable physiological detecting system. In this paper development of a smart insole for plantar pressure distribution measurement using PVDF sensors and the basic amplifier circuit.Motion measurement is an important part of physiological monitoring. It is the supporting technology of diagnosis of foot and gait analysis. At present, there are great space limitations to force sensing mat in clinical, then wearable sensing shoes or sensing insoles are more convenience and advanced, but still in the laboratory. The flexible, easy-to deformation sensing material was choose as the sensor to be placed in the insole and the insoles are soft and good elasticity. PVDF film piezoelectric material can be made as needed in textiles with sensors embedded in the performance of functional insole because its texture is soft and easy-to-cut. At the same time, some problems with the sensor design affected by the environment and material properties, such as elastic hysteresis, weak response, and distortion at high-speed exercise, the circuit is difficult to match, and so on.In the thesis, it will report the process of making sensing insole is reported, analyze and discuss test performance of the sensors, and give measurements of human cases.(1) Using PVDF piezoelectric film, with reference to mechanical features of foot motion to determine the shape, size, and wiring, making sensor chip and circuitry.(2) With the experiment, analysis of the impact of sensors of different sensor chip structure and circuit. Improve the signal response of PVDF and decrease elastic hysteresis of flexible sensor by adjusting the sensor chip structure; The value of the integral capacitor C and the feedback resistor R in the charge amplifier circuit will be determined through the experiment, so the circuitry will match the sensors, and will achieve the best testing results. Comparing the signals, select the best design to ensure that sensors are designed with the feasibility in practical applications.(3) Reference to the human foot structure and biomechanics of human foot, design sensing insole for plantar pressure distribution measurement. Build the distribution of plantar pressure measurement - acquisition systems to achieve real-time display the signal.(4) Applications designed to test the distribution of plantar pressure of human body. Through the actual test waveforms revealed the state of human motion and different pairs of shoes used to influence the distribution of plantar pressure. Analysis of the physiological significance of plantar pressure distribution, and give some advices of foot health. On the basis of human foot structure and biomechanics of foot, this paper developed a smart insole for plantar pressure distribution measurement using PVDF sensors. Improve the signal response of PVDF and decrease elastic hysteresis of flexible sensor by adjusting the sensor chip structure. Adjustment of circuit elements to make sure the circuitry will match the sensors. The development of the final application of human intelligence insole dynamic test well. The wearable sensor-based insole has good test performance in the conditions of high-speed movement of human body. Smart insoles can be used in their daily to help users to understand their own foot health, maintain a good athletic stance, which also helps to provide a basis for human gait analysis.