A Closed-loop Feedback Control System of Thermostatic Hot Film Shear Stress Microsensor

Abstract

The invention discloses a constant-temperature type hot-film shear stress micro-sensor closed-loop feedback control system, and belongs to the field of sensor measuring instruments. The adopted technical scheme of the invention comprises a hardware circuit design and an algorithm design of the hot-film shear stress micro-sensor closed-loop feedback control system. The hardware circuit is formed bya fixed resistor1, a flexible hot-film shear stress micro-sensor 4, a simulation operational amplifier 6, an instrument operational amplifier 7, a simulation multiplier 8, a microcontroller 9, and alow-noise amplifier 10. The algorithm design comprises threshold setting, design of an integration link and design of a proportion link. According to the constant-temperature type hot-film shear stress micro-sensor closed-loop feedback control system, through the design form of four-wire system measurement of the sensor resistance, the measuring error caused by a lead wire resistance of the hot-film shear stress micro-sensor is greatly reduced, and the calibration difficulty of the hot-film shear stress micro-sensor in a practical application process is reduced; besides, through dynamic and real-time adjustment of the algorithm of the microcontroller 9, the problems that according to a conventional design scheme, a self-excitation state is entered due to large-range change of the flow velocity of a flow field, and normal operation is failed are avoided.

Description

[0001] 1. Technical Field [0002] The invention relates to a closed-loop feedback control system for a thermostatic hot film shear stress microsensor, belonging to the field of sensor measuring instruments. [0003] 2. Background technology [0004] During the operation of aircrafts, ships and other aircraft, the frictional resistance of the aircraft accounts for 50%-80% of the total resistance. The frictional resistance affects the speed, energy consumption, carrying capacity, and maneuverability of the aircraft. Fluid wall shear stress is an important parameter for accurately expressing frictional resistance and describing the flow state of the fluid boundary layer. Its effective test is of great significance to the improvement of aircraft / aircraft design and experimental capabilities. [0005] As one of the important sensor components of fluid flow measurement technology, the flexible thermal film shear stress microsensor has the characteristics of high time / spatial resolution, att...

AI Technical Summary

Problems solved by technology

[0009] In order to overcome the shortcomings of the traditional design scheme such as complicated debugging process and low resistance measurement accuracy, the present invention provides a design of a closed-loop feedback control system for constant temperature hot film shear stress microsensors

Images