The Dynamics of a Ball-Type Balancer System Equipped with a Pair of Free-Moving Balancing Masses

2001 ◽  
Vol 123 (4) ◽  
pp. 456-465 ◽  
Author(s):  
Jaan-Rong Kang ◽  
Chang-Po Chao ◽  
Chun-Lung Huang ◽  
Cheng-Kuo Sung
Keyword(s):  
High Speed ◽  
Multiple Scales ◽  
Design Guidelines ◽  
Disk Drives ◽  
Rotating System ◽  
Radial Vibrations ◽  
First Order ◽  
System A ◽  
Autonomous Differential Equations ◽  
Steady State Solutions

This study is devoted to evaluate the performance of a ball-type balancer system that is installed in high-speed optical disk drives. The ball-type balancer system, composed of a circular runway and free-moving balls inside, is designed for reducing radial vibrations induced by the inherent unbalance of the rotating system. A balancer system equipped with a pair of balls is considered in this study for its capability to reach possible near-elimination of radial vibrations as opposed to the serious sizing problem of a single balancing-ball system. A mathematical model is first established to describe the dynamics of the balls and rotor system. Utilizing the method of multiple scales and assuming the smallness of radial vibrations, the system dynamics on the slow time scale is represented by eight first-order autonomous differential equations, which accommodate the radial vibratory motions and ball behaviors. The steady-state solutions of these slow equations are then solved and their stability analyzed to predict settling ball positions. The residual vibrations are computed to evaluate the performance of the balancer system and then the design guidelines are distilled for engineers to design the balancer system.

Dynamic Analysis of the Optical Disk Drives Equipped with an Automatic Ball Balancer with Consideration of Torsional Motions

2005 ◽  
Vol 72 (6) ◽  
pp. 826-842 ◽  
Author(s):  
Paul C. P. Chao ◽  
Cheng-Kuo Sung ◽  
Chun-Chieh Wang
Keyword(s):  
Multiple Scales ◽  
Spindle Motor ◽  
Optical Disk ◽  
Torsional Stiffness ◽  
Torsional Motion ◽  
Disk Drives ◽  
Scaled Model ◽  
Supporting Plate ◽  
Steady State Solutions ◽  
Balanced Solution

This study is dedicated to evaluate the performance of an automatic ball-type balancer system (ABS) installed in optical disk drives (ODDs) with consideration of the relative torsional motion between the ODD case and the spindle-disk-ABS-turntable system, noting that the turntable is the supporting plate structure for disk, pickup, and spindle motor inside the ODD. To this end, a complete dynamic model of the ABS considering the torsional motion is established with assuming finite torsional stiffness of the damping washers, which provides suspension of the spindle-disk-ABS-turntable system to the ODD case. Considering the benchmark case of a pair of balancing balls in an ABS, the method of multiple scales is then applied to formulate a scaled model for finding all possible steady-state solutions of ball positions and analyzing corresponding stabilities. The results are used to predict the levels of residual vibration, with which the performance of the ABS can then be reevaluated. Numerical simulations are conducted to verify theoretical results. It is deduced from both analytical and numerical results that the spindle speed of an ODD could be operated above both primary translational and secondary torsional resonances in order to guarantee stabilization of the desired balanced solution for a substantial vibration reduction.

Frequency Response of Parametric Resonance of Double Wall Carbon Nanotube Under Electrostatic Actuation for Noncoaxial Vibration

2017 ◽  
Author(s):  
Dumitru I. Caruntu ◽  
Ezequiel Juarez
Keyword(s):  
Carbon Nanotube ◽  
Frequency Response ◽  
Multiple Scales ◽  
Van Der Waals ◽  
First Order ◽  
Electrostatically Actuated ◽  
The Stability ◽  
Euler Bernoulli Beam ◽  
Steady State Solutions ◽  
High Length

In this paper, the Method of Multiple Scales is used to investigate the influences of dimensionless damping and voltage parameters on the amplitude-frequency response of an electrostatically actuated double-walled carbon nanotube. The forces responsible for the nonlinearities in the vibrational behavior are intertube van der Waals and electrostatic forces. Soft AC excitation and small viscous damping forces are assumed. Herein, the noncoaxial case is investigated at near-zero amplitude conditions in the free vibration, which eliminates the influence of the cubic van der Waals in the first-order solution. The DWCNT structure is modelled as a cantilever beam with Euler-Bernoulli beam assumptions since the DWCNT is characterized with high length-diameter ratio. The results shown assume steady-state solutions in the first-order MMS solution. The importance of the results in this paper are the effect of damping and detuning frequency on the stability of the DWCNT vibration.

scholarly journals Parametrically excited nonlinear systems: a comparison of two methods

2002 ◽  
Vol 32 (12) ◽  
pp. 739-761 ◽  
Author(s):  
A. F. El-Bassiouny
Keyword(s):  
Internal Resonance ◽  
Numerical Solutions ◽  
Multiple Scales ◽  
Nonlinear Ordinary Differential Equations ◽  
Generalized Synchronization ◽  
Approximate Methods ◽  
System Parameters ◽  
First Order ◽  
Two Degree Of Freedom ◽  
Steady State Solutions

Subharmonic resonance of two-degree-of-freedom systems with cubic nonlinearities to multifrequency parametric excitations in the presence of three-to-one internal resonance is investigated. Two approximate methods (the multiple scales and the generalized synchronization) are used to construct a first-order nonlinear ordinary differential equations governing the modulation of the amplitudes and phases. Steady state solutions and their stability are computed for selected values of the system parameters. The results obtained by the two methods are in excellent agreement. Numerical solutions are carried out and graphical representations of the results are presented and discussed.

scholarly journals Research on predictive sliding mode control strategy for horizontal vibration of ultra-high-speed elevator car system based on adaptive fuzzy

2021 ◽  
Vol 54 (3-4) ◽  
pp. 360-373
Author(s):  
Hong Wang ◽  
Mingqin Zhang ◽  
Ruijun Zhang ◽  
Lixin Liu
Keyword(s):  
Sliding Mode Control ◽  
High Speed ◽  
Sliding Mode ◽  
Mode Switching ◽  
Parameter Uncertainties ◽  
Horizontal Vibration ◽  
Adaptive Fuzzy ◽  
Mode Control ◽  
System A ◽  
Ultra High Speed

In order to effectively suppress horizontal vibration of the ultra-high-speed elevator car system. Firstly, considering the nonlinearity of guide shoe, parameter uncertainties, and uncertain external disturbances of the elevator car system, a more practical active control model for horizontal vibration of the 4-DOF ultra-high-speed elevator car system is constructed and the rationality of the established model is verified by real elevator experiment. Secondly, a predictive sliding mode controller based on adaptive fuzzy (PSMC-AF) is proposed to reduce the horizontal vibration of the car system, the predictive sliding mode control law is achieved by optimizing the predictive sliding mode performance index. Simultaneously, in order to decrease the influence of uncertainty of the car system, a fuzzy logic system (FLS) is designed to approximate the compound uncertain disturbance term (CUDT) on-line. Furthermore, the continuous smooth hyperbolic tangent function (HTF) is introduced into the sliding mode switching term to compensate the fuzzy approximation error. The adaptive laws are designed to estimate the error gain and slope parameter, so as to increase the robustness of the system. Finally, numerical simulations are conducted on some representative guide rail excitations and the results are compared to the existing solution and passive system. The analysis has confirmed the effectiveness and robustness of the proposed control method.

Design of New Dual-Motor Independent Drive System for Electric Vehicle

2012 ◽  
Vol 591-593 ◽  
pp. 251-258
Author(s):  
Wen Wei Wang ◽  
Cheng Lin ◽  
Wan Ke Cao ◽  
Jiao Yang Chen
Keyword(s):  
Electric Vehicle ◽  
Network Architecture ◽  
High Speed ◽  
Simulation Analysis ◽  
Stability Control ◽  
Driving System ◽  
System A ◽  
Important Direction ◽  
Time Predictability ◽  
Information Scheduling

Multi-motor wheel independent driving technology is an important direction of electric vehicle(EV). Based on the analysis of the features of existing independent driving system of electric vehicle, a new dual-motor independent driving system configuration was designed. Complete parameters matching and simulation analysis of the system include motor, reducer, and battery. Distributed control network architecture based on high-speed CAN bus was developed, and information scheduling was optimized and real-time predictability was analyzed based on the rate monotonic (RM) algorithm and jitter margin index. The vehicle lateral stability control was achieved based on coordinated electro-hydraulic active braking. Based on the new dual-motor independent driving system, a new battery electric car was designed and tested. The results show that the vehicle has excellent dynamic and economic performance.

Nonlinear Vibrations of Viscoelastic Plane Truss Under Harmonic Excitation

2014 ◽  
Vol 14 (04) ◽  
pp. 1450009 ◽  
Author(s):  
Andrew Yee Tak Leung ◽  
Hong Xiang Yang ◽  
Ping Zhu
Keyword(s):  
Steady State ◽  
Fractional Derivatives ◽  
Harmonic Excitation ◽  
Homotopy Continuation ◽  
Response Curves ◽  
System A ◽  
Structural Responses ◽  
Voigt Model ◽  
Two Degree Of Freedom ◽  
Steady State Solutions

This paper is concerned with the steady state bifurcations of a harmonically excited two-member plane truss system. A two-degree-of-freedom Duffing system having nonlinear fractional derivatives is derived to govern the dynamic behaviors of the truss system. Viscoelastic properties are described by the fractional Kelvin–Voigt model based on the Caputo definition. The combined method of harmonic balance and polynomial homotopy continuation is adopted to obtain steady state solutions analytically. A parametric study is conducted with the help of amplitude-response curves. Despite its seeming simplicity, the mechanical system exhibits a wide variety of structural responses. The primary and sub-harmonic resonances and chaos are found in specific regions of system parameters. The dynamic snap-through phenomena are observed when the forcing amplitude exceeds some critical values. Moreover, it has been shown that, suppression of undesirable responses can be achieved via changing of viscosity of the system.

Research on Reconfigurable High-Speed Serial Bus Used in High-Reliability Embedded Computer

2010 ◽  
Vol 20-23 ◽  
pp. 774-778
Author(s):  
Rui Ding ◽  
Yong Qin Hu ◽  
Wei Gong Zhang ◽  
Bo Yang
Keyword(s):  
Computer System ◽  
High Speed ◽  
Communication Protocol ◽  
High Reliability ◽  
Dynamic Reconfiguration ◽  
System A ◽  
Embedded Computer ◽  
Key Points ◽  
Application Scope

The characteristics and limitations of the buses, which are widely used nowadays, are analyzed in this paper. Because these buses don’t adapt to the high-reliability embedded computer system, a novel bus is proposed which is characterized by its high-reliability. And its capacity is reached through its unique datum’s dynamic reconfiguration mechanism. The basic architecture and communication protocol are presented in this paper. And then the key points during realization of this bus are discussed. Finally, the probably application scope and prospects are indicated.

Magnetic Erasures Due to Impact Induced Interfacial Heating and Magnetostriction

1999 ◽  
Vol 122 (1) ◽  
pp. 264-268 ◽  
Author(s):  
M. Suk ◽  
P. Dennig ◽  
D. Gillis
Keyword(s):  
Thermal Conductivity ◽  
High Speed ◽  
Magnetic Layer ◽  
Substrate Material ◽  
Contact Stresses ◽  
Dominant Factor ◽  
Disk Drives ◽  
Mechanical Contact ◽  
Low Thermal Conductivity ◽  
Interfacial Temperature

High-velocity intermittent contacts between a slider and a disk may lead to data erasure due to interfacial heating and high-speed mechanical contact stresses. These potential modes of erasure are investigated by artificially introducing high contact stresses that are not likely to be observed in disk drives. Nevertheless, the mechanisms of erasure are delineated in this study with little ambiguity by comparing the results from three different substrate materials, namely Al-Mg, glass, and Si. We show that written flux patterns can be erased if either the substrate material has low thermal conductivity or if the magnetic layer is damaged. We conclude that if the disk is not plastically damaged by high-speed contacts, then the magnetostriction effect or stress-induced erasure is insignificant. In this case, the dominant factor in erasure is a rise in the interfacial temperature, which is exacerbated by low thermal conductivity of the substrate. [S0742-4787(00)03401-9]

scholarly journals Sampling-Based Motion Planning for Free-Floating Space Robot without Inverse Kinematics

2020 ◽  
Vol 10 (24) ◽  
pp. 9137
Author(s):  
Hongwen Zhang ◽  
Zhanxia Zhu
Keyword(s):  
Motion Planning ◽  
Inverse Kinematics ◽  
Random Trees ◽  
Space Robot ◽  
Initial Configuration ◽  
First Order ◽  
System A ◽  
Planning Framework ◽  
Planning Algorithm ◽  
Differential Relationship

Motion planning is one of the most important technologies for free-floating space robots (FFSRs) to increase operation safety and autonomy in orbit. As a nonholonomic system, a first-order differential relationship exists between the joint angle and the base attitude of the space robot, which makes it pretty challenging to implement the relevant motion planning. Meanwhile, the existing planning framework must solve inverse kinematics for goal configuration and has the limitation that the goal configuration and the initial configuration may not be in the same connected domain. Thus, faced with these questions, this paper investigates a novel motion planning algorithm based on rapidly-exploring random trees (RRTs) for an FFSR from an initial configuration to a goal end-effector (EE) pose. In a motion planning algorithm designed to deal with differential constraints and restrict base attitude disturbance, two control-based local planners are proposed, respectively, for random configuration guiding growth and goal EE pose-guiding growth of the tree. The former can ensure the effective exploration of the configuration space, and the latter can reduce the possibility of occurrence of singularity while ensuring the fast convergence of the algorithm and no violation of the attitude constraints. Compared with the existing works, it does not require the inverse kinematics to be solved while the planning task is completed and the attitude constraint is preserved. The simulation results verify the effectiveness of the algorithm.

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