Parameter identification for viscoplastic models based on analytical derivatives of a least-squares functional and stability investigations

1996 ◽  
Vol 12 (4) ◽  
pp. 451-479 ◽  
Author(s):  
Rolf Mahnken ◽  
Erwin Stein
Keyword(s):  
Parameter Identification ◽  
Least Squares ◽  
Viscoplastic Models ◽  
Analytical Derivatives ◽  
Derivatives Of

scholarly journals Parameter Estimation of a Countershaft Brake for Heavy-Duty Vehicles with Automated Mechanical Transmission

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1036
Author(s):  
Yunxia Li ◽  
Lei Li
Keyword(s):  
Parameter Identification ◽  
Least Squares ◽  
Dynamic Model ◽  
Control Flow ◽  
Mechanical Transmission ◽  
Equivalent Resistance ◽  
Heavy Duty ◽  
Characteristic Parameters ◽  
Resistance Torque ◽  
Heavy Duty Vehicles

A countershaft brake is used as a transmission brake (TB) to realize synchronous shifting by reducing the automated mechanical transmission (AMT) input shaft’s speed rapidly. This process is performed to reduce shifting time and improve shifting quality for heavy-duty vehicles equipped with AMT without synchronizer. To improve controlled synchronous shifting, the AMT input shaft’s equivalent resistance torque and the TB’s characteristic parameters are studied. An AMT dynamic model under neutral gear position is analyzed during the synchronous control interval. A dynamic model of the countershaft brake is discussed, and its control flow is given. The parameter identification method of the AMT input shaft’s equivalent resistance torque is given on the basis of the least squares algorithm. The parameter identification of the TB’s characteristic parameters is proposed on the basis of the recursive least squares method (RLSM). Experimental results show that the recursive estimations of the TB’s characteristic parameters under different duty cycles of the TB solenoid valve, including brake torque estimation, estimation accuracy, and braking intensity estimation, can be effectively estimated. The research provides some reliable evidence to further study the synchronous shifting control schedule for heavy-duty vehicles with AMT.

scholarly journals Speeding-up the Fitting of the Model Defining the Ribs-bounded Contour

2017 ◽  
Vol 21 (1) ◽  
pp. 66-70
Author(s):  
Mykolas J. Bilinskas ◽  
Gintautas Dzemyda ◽  
Martynas Sabaliauskas
Keyword(s):  
Mathematical Model ◽  
Local Search ◽  
Computer Tomography ◽  
Vertical Axis ◽  
Newton Methods ◽  
Optimal Parameters ◽  
Analytical Derivatives ◽  
The Mathematical Model ◽  
Quasi Newton ◽  
Derivatives Of

Abstract The method for analysing transversal plane images from computer tomography scans is considered in the paper. This method allows not only approximating ribs-bounded contour but also evaluating patient rotation around the vertical axis during a scan. In this method, a mathematical model describing the ribs-bounded contour was created and the problem of approximation has been solved by finding the optimal parameters of the mathematical model using least-squares-type objective function. The local search has been per-formed using local descent by quasi-Newton methods. The benefits of analytical derivatives of the function are disclosed in the paper.

scholarly journals Least-squares Based Parameter Identification for a Function-related Surface Optimisation in Micro Ball-end Milling

Procedia CIRP ◽  
2015 ◽  
Vol 31 ◽  
pp. 276-281 ◽  
Author(s):  
J. Vehmeyer ◽  
I. Piotrowska-Kurczewski ◽  
F. Böhmermann ◽  
O. Riemer ◽  
P. Maaß
Keyword(s):  
Parameter Identification ◽  
Least Squares ◽  
End Milling ◽  
Ball End Milling

scholarly journals Payload Parameter Identification of a Flexible Space Manipulator System via Complex Eigenvalue Estimation

2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Zhiyu Ni ◽  
Shunan Wu ◽  
Yewei Zhang ◽  
Zhigang Wu
Keyword(s):  
Parameter Identification ◽  
Least Squares ◽  
State Space Model ◽  
Recursive Least Squares ◽  
Mode Shapes ◽  
Identification Algorithm ◽  
Complex Eigenvalue ◽  
Nonlinear Dynamic Model ◽  
Space Manipulator ◽  
Affine Projection

Manipulator systems are widely used in payload capture and movement in the ground/space operation due to their dexterous manipulation capability. In this study, a method for identifying the payload parameters of a flexible space manipulator using the estimated system of complex eigenvalue matrix is proposed. The original nonlinear dynamic model of the manipulator is linearized at a selected working point. Subsequently, the system state-space model and corresponding complex eigenvalue parameters are determined by the observer/Kalman filter identification algorithm using the torque input signal of the motor and the vibration output signals of the link. Therefore, the inertia parameters of the payload, that is, the mass and the moment of inertia, can be derived from the identified complex eigenvalue system and mode shapes by solving a least-squares problem. In numerical simulations, the proposed parameter identification method is implemented and compared with the classical recursive least-squares and affine projection sign algorithms. Numerical results demonstrate that the proposed method can effectively estimate the payload parameters with satisfactory accuracy.

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