Dynamic friction modelling without drift and its application in the simulation of a valve controlled hydraulic cylinder system

Yang, Jian; Plummer, Andrew

doi:10.1299/jamdsm.2014jamdsm0075

Cited by 3 publications

(2 citation statements)

References 28 publications

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“…The nonlinear behavior caused by friction has an adverse influence on the ultra-low velocity and high precision position control of servo mechanisms [24], which could lead to stick-slip and limit cycles during movement of inner and outer gimbals [25]. For direct-driven gimbals, the friction mainly comes from bearings.…”

Section: Analysis Of Nonlinear Ftmentioning

confidence: 99%

A Uniform Method of Mechanical Disturbance Torque Measurement and Reduction for the Seeker Gimbal in the Assembly Process

Shang

2017

Mathematical Problems in Engineering

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In the manufacturing process of seekers, the reduction of disturbance torques (DTs) is a critical but time-consuming work. The innovation of the paper is to present a uniform method to measure and reduce mechanical DTs during gimbal's assembly process. Firstly, the relationships between assembly parameters and DTs are established and analyzed by theoretical model. And then, a measuring system is established to measure the driven torque of the gimbal's torque motor. With the goal of stabilizing and minimizing the driven torque, all assembly parameters relating to DTs could be adjusted. Through the proof of a lot of experiments, this proposed method could reduce the bias and fluctuation of these mechanical DTs. This method could also be used for the mechanical DTs reduction of most similar productions and improve the quality and efficiency during their system assembly process.

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Section: Analysis Of Nonlinear Ftmentioning

confidence: 99%

A Uniform Method of Mechanical Disturbance Torque Measurement and Reduction for the Seeker Gimbal in the Assembly Process

Shang

2017

Mathematical Problems in Engineering

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“…Amongst these factors, nonlinear frictional moment, which mainly comes from bearings for directly driven gimbal, is normally the major stabilization error source (Stockum, et al, 1988). The nonlinear behavior caused by friction has an adverse influence on the ultra-low velocity and high precision position control of servo mechanisms (Yang, et al, 2014), which could lead to stick-slip and limit cycles during movement of inner and outer gimbals (Olsson and Astrom, 2001, Cheock, et al, 1988). Moreover, friction degrades stabilization by acting as the transference mechanism for base motion disturbance (Lagunowich, et al, 2007).…”

Section: Introductionmentioning

confidence: 99%

Frictional torque analyzing and testing of Gimbaled-mirror seeker under changing environment temperature

Shang

2017

JAMDSM

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IntroductionThe seeker is one of the most important parts of a missile. It's used to track the target and to provide the inertial stabilization to the detector's pointing vector (Yu and Zhao, 2008). A seeker is generally composed of a detector, a controller for acquisition and tracking and a two-axis orthogonal gimbal system. In the task of long-range precision strike or target positioning, the stability of seeker's line-of-sight (LOS) is crucial to hit accuracy and target location accuracy of a missile. As a highly integrated and high-precision optical-mechatronic system, there might be many factors in a seeker which might degrade the stabilization precision of LOS, such as disturbance torques, gyro noise and drift, structural resonance frequency, control bandwidth, etc (Hilkert, 2008). Amongst these factors, nonlinear frictional moment, which mainly comes from bearings for directly driven gimbal, is normally the major stabilization error source (Stockum, et al., 1988). The nonlinear behavior caused by friction has an adverse influence on the ultra-low velocity and high precision position control of servo mechanisms (Yang, et al., 2014), which could lead to stick-slip and limit cycles during movement of inner and outer gimbals (Olsson and Astrom, 2001, Cheock, et al., 1988). Moreover, friction degrades stabilization by acting as the transference mechanism for base motion disturbance (Lagunowich, et al., 2007). With the development of lightweight, miniaturized seekers, the effect of nonlinear friction is becoming more and more pronounced.Temperature is a critical factor that could change the value of friction torque and its fluctuation property. Ambient temperature of a missile would be very different because of the broad geographical deployment and different seasons, and the environment temperature might change in a wide range of -40℃~+60℃ or much more severe. Especially, in the course of high-speed flight and high-g maneuver, a missile would go through airspace with different temperature and generate immense heat because of friction with atmospheric air, so the temperature of gimbal fluctuates sharply during missile flight. As a consequence, friction torque of gimbal would rise or fall along with the change of ambient temperature. AbstractNonlinear friction is the main stabilization error source of missile's seeker. In this paper, the frictional torque of a gimbaled-mirror seeker under changing environment temperature is analyzed. The torque is consisted of rolling friction due to elastic hysteresis, sliding friction due to pivoting and friction torque due to lubricant viscosity. Based on the theory of thermo-elasticity, axial and radial coupling thermal deformation between precision bearing and its installation structure are both included in the analysis model. Coupling deformation dramatically changes the actual contact angle and axial force of bearing, which consequently change the value of frictional torque. Temperature effect on viscosity of lubricant is also studied and improved Walther Equation is used...

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On the design of unconventional testing machines for engineering testing – the case study of advanced joining processes unit

Tenreiro,

Carbas,

Marques

et al. 2024

Journal of Machine Design and Automation Intelligence

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Structural adhesive joining has become a widely used joining method for various types of structures, thus avoiding more conventional joining methods. In this manner, adhesive materials may be present in structures which suffer loading conditions that may not be normally considered in the design phase, such as high-strain rate conditions or creep and torsional loading. In these situations, adhesive properties and mechanical behaviour are sometimes not well understood, thus requiring special machine testing setups that can only be built for the specific application. Therefore, this paper provides a brief overview of proposed machine architectures for a torsion testing apparatus, a tensile & compressive Split Hopkinson Pressure Bar (SHPB), a drop-weight apparatus and a three station creep testing machine with a climactic chamber. Each testing apparatus has been designed by graduate students during their master thesis projects, and facilitated in the production of interesting and relevant scientific output in the field of structural adhesive behaviour.

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Dynamic friction modelling without drift and its application in the simulation of a valve controlled hydraulic cylinder system

Cited by 3 publications

References 28 publications

A Uniform Method of Mechanical Disturbance Torque Measurement and Reduction for the Seeker Gimbal in the Assembly Process

A Uniform Method of Mechanical Disturbance Torque Measurement and Reduction for the Seeker Gimbal in the Assembly Process

Frictional torque analyzing and testing of Gimbaled-mirror seeker under changing environment temperature

On the design of unconventional testing machines for engineering testing – the case study of advanced joining processes unit

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