Papers by Keyword: Parameter Identification

Abstract: In this paper, the mathematical model of unmanned gliding-hydrofoil craft’s maneuverability is established by parameter identification theory. The objective function is established based on the data obtained in the experiment in towing tank. Two kinds of identification programs that genetic algorithm(GA) and particle swarm optimization(PSO) are written based on MATLAB. Each parameter of the objective function is identified based on the two programs respectively. The feasibility of the mathematical model is manifested by comparing the results of identification with experimental data. A full analysis and comparison is performed at the optimize efficiencies of the two programs.

Abstract: . For effectively using flight test data to extract drag coefficient, an optimal observer based on parameter estimation technique is proposed. The point mass dynamic equation is used to form the Unscented Kalman Filter (UKF) and the smoother (URTSS) for the estimation of a projectile’s flight states. The projectile flight states are then solved and utilized to extract the drag coefficient information using the observer techniques. The simulation verifies the feasibility of the method: with measurement noise, the accurate drag coefficient is obtained by using the smoother.

Abstract: High precision calibration of Micro inertial measurement unit (MIMU) for large installation misalignment can improve the instrument and the practical use of the system precision. It can use high precision turntable to get the coarse value of installation misalignment angle as the optimization initial value, and take the standard deviation of turntable angular rate and the acceleration of gravity as the optimum index to find MIMU misalignment parameters using artificial fish swarm algorithm. Simulation and analysis are carried out based on the position and rate experiment. In addition, static navigation test is taken by using self-developed MEMS heading and attitude measurement system. Both the simulation and experimental results show that this method can improve the calibration accuracy of MIMU effectively with reduced of heading and attitude error.

Abstract: This paper proposed a separated-frequency identification method of Li-ion battery model for Electric Vehicles (EVs). The main idea is to decompose the measured terminal voltage and current data in wavelet domain, and then the weighting least squares (LS) algorithm is used to extract the model parameters. Since the signal energy of open circuit voltage (OCV) mainly distributes in the low frequency band, the identifiable wavelet-domain battery model can be approximately obtained by neglecting the high frequency wavelet decomposition coefficients. Furthermore, based on the Akaike’s information criterion, we study the optimum decomposition order of the wavelet-domain battery model.

Abstract: The nonlinear model of hydro turbine considering the elastic water column was proposed, and the improved biogeography-based optimization (IBBO) algorithm was applied to identify parameters of this model. The cosine species migration model and the elitist reservation strategy were introduced into the algorithm to improve operating efficiency. Based on measured data, comparison of the effects of different identification methods was presented, including the IBBO algorithm, genetic algorithm (GA) and particle swarm optimization (PSO). The results demonstrated that the IBBO algorithm can be applied in parameters identification of hydro turbine nonlinear model, and it has the advantages of faster convergence and higher precision.

Abstract: Hydraulic resistance coefficient (HRC) is a fundamental parameter that characterizes the hydraulic state of a water pipeline and significantly determines the efficiency of the water-transport process. To estimate HRC and diagnose hydraulic process fault in building air conditioning system, a novel method called multi-objective optimization (MBO) strategy was developed in the research effort. MBO is concerned with mathematical optimization problems involving more than one objective function to be optimized simultaneously. In this paper, first, the basic principle of the approach is presented. Then several experiments are conducted to identify the HRC in a real air conditioning system. And the water flow rate of each air handling terminal unit is estimated by the flow rate of primary pipe and identified HRC. The experiment results show that the model can accurately estimate HRCs. The HRCs of each pipe and terminal unit were obtained by the flow rate and the pressure difference of primary pipe without requiring geometric specifications, which is very convenient in real engineering application.

Abstract: Real-time accuracy of the permanent magnet synchronous motor (PMSM) parameter directly affects the performance of the servo system. In this paper, the model reference adaptive parameter identification method, the parameters of permanent magnet synchronous motor running as the actual model , the mathematical model derived from the equation of state in the d, q coordinate system as the theoretical model , in order to calculate the real-time stator resistance , inductance and rotor flux value . Thereby increasing the accuracy of the vector control .Using simulink simulation results show that, The system can quickly and accurately calculate the real-time parameters and the applied control.

Abstract: It is inevitable that the mechanical part has error when machining. To increasing the machining precision and decreasing the shape and position error, error compensation is one way. The geometry error parameter is necessary when the error compensation model is founded and the compensation data is calculated. The common measuring and identifying methods are introduced in this article. Their mathematic models and solutions are listed and their merits and drawbacks are compared. This method has been applied in CNC error compensation and the effect is advisable.

Abstract: With elastic modulus perturbation parameter of blade as mistuned parameter, a parameter identification method of mistuned blades is presented based on static frequency test , bisection method and finite element method. Take mistuned blades of the compressor as an example,the mistuned parameter of blades are identified. The identification results show that this method is high precision and fast speed.

Abstract: In this paper, the nonlinear dynamic system of microbe continuous fermentation products 1,3-propanediol (1,3-PD) is rewritten by improving the specific cellular growth rate, specific substrate consumption rate and specific product formation rate. Firstly, under the condition of substrate glycol excess and active trans-membrane transport, according to the dynamic behavior the fermentation process, we consider the glycerol and 1,3–PD concentration within the cell, and improve the specific cellular growth rate, specific substrate consumption rate and specific product formation rate, then rewrite the dynamic system of microbial continuous fermentation process. Secondly, taking the dynamic system as main constraint condition, we establish the parameter identification model and prove the existence of the optimal solution. Lastly, the numerical results calculated by particle swarm algorithm show that the improved model is suitable for describe the dynamic behavior of 1,3-PD, but is not accurate enough for by-products.