2020 ◽  
pp. 67-73
Author(s):  
N.D. YUsubov ◽  
G.M. Abbasova

The accuracy of two-tool machining on automatic lathes is analyzed. Full-factor models of distortions and scattering fields of the performed dimensions, taking into account the flexibility of the technological system on six degrees of freedom, i. e. angular displacements in the technological system, were used in the research. Possibilities of design and control of two-tool adjustment are considered. Keywords turning processing, cutting mode, two-tool setup, full-factor model, accuracy, angular displacement, control, calculation [email protected]


2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Jianyong Yao ◽  
Guichao Yang ◽  
Dawei Ma

The integration of internal leakage fault detection and tolerant control for single-rod hydraulic actuators is present in this paper. Fault detection is a potential technique to provide efficient condition monitoring and/or preventive maintenance, and fault tolerant control is a critical method to improve the safety and reliability of hydraulic servo systems. Based on quadratic Lyapunov functions, a performance-oriented fault detection method is proposed, which has a simple structure and is prone to implement in practice. The main feature is that, when a prescribed performance index is satisfied (even a slight fault has occurred), there is no fault alarmed; otherwise (i.e., a severe fault has occurred), the fault is detected and then a fault tolerant controller is activated. The proposed tolerant controller, which is based on the parameter adaptive methodology, is also prone to realize, and the learning mechanism is simple since only the internal leakage is considered in parameter adaptation and thus the persistent exciting (PE) condition is easily satisfied. After the activation of the fault tolerant controller, the control performance is gradually recovered. Simulation results on a hydraulic servo system with both abrupt and incipient internal leakage fault demonstrate the effectiveness of the proposed fault detection and tolerant control method.


2021 ◽  
Vol 13 (13) ◽  
pp. 7174
Author(s):  
Massimo Rundo ◽  
Paolo Casoli ◽  
Antonio Lettini

In hydraulic components, nonlinearities are responsible for critical behaviors that make it difficult to realize a reliable mathematical model for numerical simulation. With particular reference to hydraulic spool valves, the viscous friction coefficient between the sliding and the fixed body is an unknown parameter that is normally set a posteriori in order to obtain a good agreement with the experimental data. In this paper, two different methodologies to characterize experimentally the viscous friction coefficient in a hydraulic component with spool are presented. The two approaches are significantly different and are both based on experimental tests; they were developed in two distinct laboratories in different periods of time and applied to the same flow compensator of a pump displacement control. One of the procedures was carried out at the Fluid Power Research Laboratory of the Politecnico di Torino, while the other approach was developed at the University of Parma. Both the proposed methods reached similar outcomes; moreover, neither method requires the installation of a spool displacement transducer that can significantly affect the results.


Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 55
Author(s):  
Nicholas Hawkins ◽  
Bhagyashri Bhagwat ◽  
Michael L. McIntyre

In this paper, a nonlinear controller is proposed to manage the rotational speed of a full-variable Squirrel Cage Induction Generator wind turbine. This control scheme improves upon tractional vector controllers by removing the need for a rotor flux observer. Additionally, the proposed controller manages the performance through turbulent wind conditions by accounting for unmeasurable wind torque dynamics. This model-based approach utilizes a current-based control in place of traditional voltage-mode control and is validated using a Lyapunov-based stability analysis. The proposed scheme is compared to a linear vector controller through simulation results. These results demonstrate that the proposed controller is far more robust to wind turbulence than traditional control schemes.


2021 ◽  
Vol 158 ◽  
pp. 107769
Author(s):  
Wenxiang Deng ◽  
Jianyong Yao ◽  
Yaoyao Wang ◽  
Xiaowei Yang ◽  
Jiuhui Chen

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Mehran Pirooz ◽  
Seyed Hossein Mirmahdi ◽  
Ahmad Reza Khoogar

AbstractIn this paper, a new approach is proposed to control the dynamic response of a landing gear system subjected to runway force, both on heavy landing conditions and at the taxiing process. The mathematical model of the system is used in a way that covers nonlinear dynamics characteristics of landing gear and nonlinear/nonaffine property of the external actuator. The operation of the landing gear system and its components are described briefly. The desired control system includes two different interior loops for displacement and force control. The inner loop determines the actuator force and the outer loop performs the displacement control. A lumped uncertainty is considered in both displacement and force control loops that represent uncertainties including parametric errors, measurement noises, unmodeled dynamics, disturbance due to runway excitation, and other disturbances. The direct method of Lyapunov is utilized for asymptotic stability analysis of the robust nonlinear control system (RNCS). This system is simulated in MATLAB software and the performance of the proposed controller is analyzed exactly. Besides, the results are compared with a passive system and conventional PID control. The comparison indicates that RNCS works better and more precisely. This method can reduce vibrations at touchdown and taxiing and effectively overcome uncertainty and provide well aircraft handling by decreasing the changes in tire force.


Author(s):  
Byron Hernandez ◽  
Michael Felipe Cifuentes Molano ◽  
Eduardo Giraldo
Keyword(s):  

2008 ◽  
Author(s):  
A. TalebiTaher ◽  
M. Ghoranneviss ◽  
R. Tarkeshian ◽  
P. Khorshid ◽  
M. K. Salem ◽  
...  

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