Article
Engineering, Chemical
Kai Wang, Gexin Chen, Tiangui Zhang
Summary: This study investigates the rolling mechanism and process procedure of electrode roll-forming based on micro-displacement position control considering friction factors. A friction compensation controller based on the LuGre model is designed, and the system's control precision is improved through combination with an adaptive robust controller.
Article
Engineering, Mechanical
Sunit K. Gupta, Ehab E. Basta, Oumar R. Barry
Summary: This study presents a comprehensive analysis of an MBMS with a nonlinear FI. The inclusion of nonlinearity in the friction isolator significantly increases the local stability of the system's fixed-points, allowing for larger differential gains in the servocontrolled motion stage. The system exhibits sub and supercritical Hopf bifurcation, and the region of bifurcation depends on the nonlinearity in the FI.
JOURNAL OF COMPUTATIONAL AND NONLINEAR DYNAMICS
(2023)
Article
Automation & Control Systems
Paria Moradi, Moharram Habibnejad Korayem, Naeim Yousefi Lademakhi
Summary: In this article, the values of torque loss due to friction in robot joints were identified, and a model for this phenomenon was presented using the lugre friction model and nonlinear least-squares error-estimation method. Three forms of the lugre friction model were used to model the system's friction, with the third model including a nonlinear viscous term. The performance of the designed algorithms was examined using a nonlinear sliding mode controller. The results showed the superiority of the identified models with time-varying parameters. The accuracy of the proposed friction models was validated through simulations on a 6R laboratory robot.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART I-JOURNAL OF SYSTEMS AND CONTROL ENGINEERING
(2023)
Article
Automation & Control Systems
Jian Li, Yong Lu, Fengshuo He, Lixian Miao
Summary: Friction force is crucial in motion control systems, especially for hydraulic actuators. The nonlinear nature of friction force greatly affects control performance. This paper developed a friction force test bench and studied the transient friction force of a hydraulic actuator with one-way seals. The results showed that the friction force was asymmetric between instroke and outstroke stages, leading to the introduction of the bristle direction hypothesis to improve the LuGre model and develop a backstepping controller for compensating the nonlinear friction force.
Article
Chemistry, Multidisciplinary
Tianyu Gao, Hao Chen, Danna Tang, Yumo Wang
Summary: Inspired by earthworms and leeches, the performance of the piston-cylinder liner friction pair was improved through biomimetic design and processing. The results showed that the pistons with cylindrical pit arrays exhibited excellent friction and wear performance, prolonging the lifespan of the piston and reducing heat generation and scratches on the cylinder liner.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Mechanical
Steven W. Shaw, Sahar Rosenberg, Oriel Shoshani
Summary: Models for nonlinear vibrations often use polynomial terms to simulate nonlinear phenomena. The analysis of symmetric systems with cubic stiffness terms is common, and the inclusion of asymmetric quadratic terms is known to modify the effect of cubic nonlinearity in weakly nonlinear systems. However, in many cases, a monotonic dependence is not observed, requiring the use of techniques for strongly nonlinear systems or higher-order terms and perturbation methods.
NONLINEAR DYNAMICS
(2023)
Article
Mechanics
G. Rill, T. Schaeffer, M. Schuderer
Summary: The LuGre model is frequently used for analyzing and controlling friction systems. However, it has drawbacks, such as low break-away forces, force rate-dependency, drift problems during sticking, and differences between the pre-defined friction law and the one produced by the LuGre model. These drawbacks are caused by a simplistic and inconsistent modeling of bristle dynamics rather than the model dynamics or its nonlinearity.
MULTIBODY SYSTEM DYNAMICS
(2023)
Article
Engineering, Mechanical
Yan-he Song, Kai-xian Ba, Yuan Wang, Jun-xiao Zhang, Bin Yu, Qi-wei Zhang, Xiang-dong Kong
Summary: This paper studies the phenomenon of self-excited oscillation caused by nonlinear factors in a large aircraft wheel brake control system. It explores the nonlinear dynamic behavior of the pressure servo valve-controlled cylinder system (PSVCS) and analyzes the influence of key parameters on the nonlinear self-excitation behavior. The stability of the PSVCS is analyzed in both time and frequency domains, and experimental verification is conducted to validate the theoretical results. The conclusions provide important references for the design of braking system control systems.
NONLINEAR DYNAMICS
(2022)
Article
Engineering, Aerospace
P. M. Patil, H. F. Shankar
Summary: This study analyzed the flow of hybrid nanofluid around yawed cylinders using viscous dissipation. The results showed that the hybrid nanofluid reduces velocity distribution and increases surface drag coefficient, while having higher fluid temperature and energy transport strength compared to base fluid and nanofluid.
PROPULSION AND POWER RESEARCH
(2022)
Article
Thermodynamics
Puneet Rana, Akash Kumar
Summary: The buoyancy driven flow on a vertical cylinder has applications in various engineering fields. In this study, the flow of water transporting hybrid nano-particles around a spinning cylinder surface subjected to quadratic radiative heat transfer is investigated. The research shows that heat transport is greater for quadratic radiation/convection compared to linear thermal radiation/convection. The governing partial differential equations are solved using a discretization method, and the maximum average heat transport is achieved through response surface methodology.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2022)
Article
Physics, Fluids & Plasmas
Cihan Ayaz, Laura Scalfi, Benjamin A. Dalton, Roland R. Netz
Summary: We present a hybrid projection scheme that combines linear Mori projection and conditional Zwanzig projection techniques to derive a generalized Langevin equation (GLE) for a general interacting many-body system. The resulting GLE includes the potential of mean force (PMF) that describes the equilibrium distribution of the system, a random force term that depends on the initial state of the system, and a memory friction contribution. Our hybrid scheme combines desirable properties of Zwanzig and Mori projection schemes. The nonlinear memory friction contribution is related to correlations between the reaction-coordinate velocity and the random force.
Article
Thermodynamics
Shouling Jiang, Hui Wang, Guochao Zhao
Summary: This paper proposes a model reference adaptive disturbance rejection control method based on neural network for digital hydraulic cylinders. By introducing dead zone model, ESO, and RBF network, the control accuracy and system robustness can be effectively improved.
ADVANCES IN MECHANICAL ENGINEERING
(2022)
Article
Physics, Multidisciplinary
Nadeem Abbas, S. Nadeem, Anber Saleem, M. Y. Malik, Alibek Issakhov, Fahd M. Alharbi
Summary: The study focuses on the stagnation point flow of hybrid nanofluid with inclined magnetic field over a moving cylinder, using mathematical models and boundary layer approximations to convert systems of partial differential equations to dimensionless systems of ordinary differential equations for numerical solutions. The effects of physical parameters variation are depicted through graphs, and skin friction coefficient and Nusselt number are highlighted through tables. The main objective is to investigate the heat transfer rate on the surface of the nonlinear stretching cylinder, comparing the results of Xue model and Yamada-Ota model for the hybrid nanofluid. In both cases, velocity and temperature profiles are best compared to the decay results.
CHINESE JOURNAL OF PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Junjie Zhou, Tianrui Li, Dongyun Wang
Summary: This paper discusses the friction issues of swash plate type axial piston pumps in hydraulic systems, focusing on the key piston-cylinder interface. It conducts a detailed study on factors such as fluid film geometry, part dimensions, and temperature, proposing a novel fluid-structure-thermal interaction model for analysis and simulation.
APPLIED SCIENCES-BASEL
(2021)
Article
Chemistry, Multidisciplinary
Donglai Yang, Xingrong Huang, Xiaodong Yang
Summary: This paper presents a hybrid control strategy by adjusting the normal force applied on the friction damper to achieve vibration reduction effect, and considering the combination of dry friction force and velocity control force in the active control law. Simulation results demonstrate that the proposed control law can reduce the amplitude of the active control force by about 5% without degrading the control efficiency.
APPLIED SCIENCES-BASEL
(2021)
