Research on Excitation Signal and Frequency Domain Identification of the Servo Control System
|School||Harbin Institute of Technology|
|Course||Control Science and Engineering|
|Keywords||Servo System Frequency domain identification Incentive Design Chaotic signals Bandwidth-constrained|
Motion control system is widely used in all areas of industry , such as semiconductor packaging , CNC machine tools , industrial robots . System identification is the basis for the design of the controller , especially in the high speed and high precision motion control system design process , the identification of appropriate systems to improve the performance of the control system to provide the most basic knowledge . In this thesis , the research work include the following aspects : (1) servo control object mechanism modeling based on the gray box identification . Simplify the design of the controller control system operates below the cutoff frequency for the convenience of papers departure from the design point of view of the excitation signal , by ignoring the high frequency band model to approximate the system model , the analysis of the system cutoff frequency 3dB down at a frequency point a lot of work such as frequency domain characteristics . (2) select the excitation signal for the identification of theoretical analysis, a wide band of pseudo-random binary signal , it will stimulate the high-frequency modes of the system , and on simulation analysis pseudo-random binary signal is not suitable to be chosen as the need to ignore the high the conclusions of the excitation signal band model identification . ( 3 ) analysis of the spectral bandwidth of the input signal , the amplitude of the differential signal amplitude , designed for mechanical and electrical system identification sweep signal , the instantaneous frequency sweep signal changes linearly with time , while the least-squares iterative algorithm for identification time-dependent , so the identification result with the sweep cycle change periodically , and the identification result does not converge . (4 ) The paper presents a chaotic signal as excitation signal electromechanical system identification , because the signal has spectral characteristics of continuous, smooth , and its bandwidth can be set limits . Frequency response experimental design suitable for mechanical and electrical system identification chaotic signal for identification , recognition results convergence frequency domain characteristics of the system are obtained . Verification experiment proved chaotic signal is a good electrical and mechanical system identification excitation signal , can be safely applied to electrical and mechanical systems , can be a good approximation in the low - frequency model .