Analytical model for the approximation of hysteresis loop and its application to the scanning tunneling microscope
A new model description and type classification carried out on its base of a wide variety of practical hysteresis loops are suggested. An analysis of the loop approximating function was carried out; the parameters and characteristics of the model were defined—coersitivity, remanent polarization, value of hysteresis, spontaneous polarization, induced piezocoefficients, value of saturation, hysteresis losses of energy per cycle. It was shown that with piezomanipulators of certain hysteresis loop types, there is no difference in heat production. The harmonic linearization coefficients were calculated, and the harmonically linearized transfer function of a nonlinear hysteresis element was deduced. The hysteresis loop type was defined that possesses minimum phase shift. The average relative approximation error of the model has been evaluated as 1.5%-6% for real hysteresis loops. A procedure for definition of the model parameters by experimental data is introduced. Examples of using the results in a scan unit of a scanning tunneling microscope for compensation of raster distortion are given.