Engine Power Measuring System Based On Laser Speckle

In traditional measuring systems, some sensors fixed on the rotative part of the engine are needed when measuring the power or rotative speed of the engine. Using these sensors, the preparation work takes much time before measuring and the cost of them are much high. Meanwhile, the system measuring accuracy will be affected. This new type of power measuring system is based on the laser speckle phenomenon, and it doesn' t need any touch to the shaft driven by the engine. It has the priority of high accuracy, high efficiency, low cost, easy operation, and so on. This kind of measuring system will open up vast market vistas with great theory meaning and value of application.Laser speckle phenomenon happens when a laser beam reflected by a reflection surface interferes with itself. The speckle image created by a special reflection surface is fixed and it will change with the changing of the surface. Especially when the target to be measured is rotating the speckle image will change with periodicity. With the rapid development of some related subjects, now we can develop a new type of instrument based on the character of laser speckle phenomenon to measure the torque of an engine. It depends on the signals of two independent laser beams that created by two laser creators. The signals come from the rotative surface of the sharft when the laser beams are projected on it. They will be used to measuring the torsion deformation of the shaft caused by the torque, therefore the torque is got.The author of this paper discusses the measuring theory with specification by using some formulas and graphs, and analyzes the reason caused the devation and its affection to the measure result in theory. The configurations of the hardware, their connection methods, and the wholestructure of the system are introduced. The development software platform and application programs are also described here to some extend.To meet the demand for dynamic measuring and remote controlling, the author considers the internet function for this system sufficiently. It has realizing the function of publishing data and image on internet and remote control included. The structure of the system for the net module is also shown in this paper.