Analysis of the Multiple Flying Height States in the Load/Unload HDD Systems Using the 4-DOF Suspension Model

2007 ◽  
Author(s):  
P. Khan ◽  
P. Hwang
Keyword(s):  
Suspension System ◽  
Flying Height ◽  
Air Bearing ◽  
Suspension Model

The 4-DOF suspension model is employed in order to analyze the multiple flying height states of the coupled air bearing – suspension system. The results are compared with previously presented results for the simpler suspension model.

Performance of Sliders Flying Over Discrete-Track Media

2007 ◽  
Vol 129 (4) ◽  
pp. 712-719 ◽  
Author(s):  
Jianhua Li ◽  
Junguo Xu ◽  
Yuki Shimizu
Keyword(s):  
Estimation Method ◽  
Simulation Method ◽  
Measured Data ◽  
Flying Height ◽  
Height Loss ◽  
Air Bearing ◽  
Slider Air Bearing ◽  
Discrete Track ◽  
Flying Attitude ◽  
Manufacturing Variation

A simulation method in which grooves are virtually distributed on the slider air bearing instead of on the grooved medium surface has been developed and used to investigate the performance of sliders flying over the surface of a discrete-track medium. The simulated flying height loss due to a discrete-track medium coincides well with the measured data, whereas the average-estimation method overestimates flying height loss. Among the characteristics of a slider flying over the surface of a discrete-track medium that were studied are the flying attitude, the effect of groove parameters on flying profile, and the flying height losses due to manufacturing variation and altitude. The results indicate that when a slider is flying over the surface of a discrete-track medium, it will have a higher 3σ of flying height, be more sensitive to altitude, and will have a greater flying height loss.

Effect of Intermolecular Forces on the Static and Dynamic Performance of Air Bearing Sliders: Part II—Dependence of the Stability on Hamaker Constant, Suspension Preload and Pitch Angle

2005 ◽  
Vol 128 (1) ◽  
pp. 203-208 ◽  
Author(s):  
Vineet Gupta ◽  
David B. Bogy
Keyword(s):  
Pitch Angle ◽  
Dynamic Performance ◽  
Hard Disk Drives ◽  
Intermolecular Forces ◽  
Flying Height ◽  
Total Force ◽  
Air Bearing ◽  
Force Increase ◽  
The Stability ◽  
Fly Height

Intermolecular and surface forces contribute significantly to the total forces acting on air bearing sliders for flying heights below 5 nm. Their contributions to the total force increase sharply with the reduction in flying height, and hence their existence can no longer be ignored in air bearing simulation for hard disk drives. Various experimentally observed dynamic instabilities can be explained by the inclusion of these forces in the model for low flying sliders. In this paper parametric studies are presented using a 3-DOF model to better understand the effect of the Hamaker constants, suspension pre load and pitch angle on the dynamic stability/instability of the sliders. A stiffness matrix is used to characterize the stability in the vertical, pitch, and roll directions. The fly height diagrams are used to examine the multiple equilibriums that exist for low flying heights. It has been found that the system instability increases as the magnitude of the van der Waals force increases. It has also been found that higher suspension pre load and higher pitch angles tend to stabilize the system.

SUSPENSION OPTIMIZATION USING DESIGN OF EXPERIMENT (DOE) METHOD ON MSC/ADAMS-INSIGHT

2015 ◽  
Vol 75 (8) ◽  
Author(s):  
N. Ikhsan ◽  
R. Ramli ◽  
A. Alias
Keyword(s):  
Design Of Experiment ◽  
Suspension System ◽  
Optimization Process ◽  
Data Set ◽  
Pareto Chart ◽  
Axis Direction ◽  
Parallel Movement ◽  
Suspension Model ◽  
Vehicle Suspension System ◽  
Multi Body

In this paper, the optimum setting for suspension hard points was determined from a half vehicle suspension system. These optimized values were obtained by considering the Kinematic and Compliance (K&C) effects of a verified PROTON WRM 44 P0-34 suspension model developed using MSC/ADAMS/CAR. For optimization process, multi body dynamic software, MSC/ADAMS/INSIGHT and Design of Experiment (DoE) method was employed. There were total of 60 hard points (factors) in x, y and z axis-direction for both front and rear suspension while toe, camber and caster change were selected as the objective function (responses) to be minimized. The values of 5 mm, 10 mm and 15 mm were used as relative values of factor setting to determine the factor range during optimization process. The hard point axis-direction that has the most effects on the responses was identified using the Pareto chart to optimize while the rests were eliminated. As expected result, a new set of suspension system model with a selected of Kinematic and Compliance (K&C) data set were obtained, and compared with the verified simulation data when subjected to the vertical parallel movement simulation test to determine the best setting and optimum suspension hard points configuration.  

Adaptive fault-tolerant control for active suspension systems based on the terminal sliding mode approach

2019 ◽  
Vol 234 (2) ◽  
pp. 501-511
Author(s):  
Amirhossein Kazemipour ◽  
Alireza B Novinzadeh
Keyword(s):  
Control Strategy ◽  
Control Method ◽  
Fault Tolerant ◽  
Sliding Mode ◽  
Fault Tolerant Control ◽  
Active Suspension ◽  
Suspension System ◽  
Terminal Sliding Mode ◽  
Car Suspension ◽  
Suspension Model

In this paper, a control system is designed for a vehicle active suspension system. In particular, a novel terminal sliding-mode-based fault-tolerant control strategy is presented for the control problem of a nonlinear quarter-car suspension model in the presence of model uncertainties, unknown external disturbances, and actuator failures. The adaptation algorithms are introduced to obviate the need for prior information of the bounds of faults in actuators and uncertainties in the model of the active suspension system. The finite-time convergence of the closed-loop system trajectories is proved by Lyapunov's stability theorem under the suggested control method. Finally, detailed simulations are presented to demonstrate the efficacy and implementation of the developed control strategy.

Ultra-low flying height air bearing designs

2000 ◽  
Vol 36 (5) ◽  
pp. 2733-2735 ◽  
Author(s):  
M.A. Dufresne ◽  
A.K. Menon
Keyword(s):  
Flying Height ◽  
Air Bearing

Research on the Decoupling Control Algorithm of Full Vehicle Semi-Active Suspension

2012 ◽  
Vol 479-481 ◽  
pp. 1355-1360
Author(s):  
Jian Guo Chen ◽  
Jun Sheng Cheng ◽  
Yong Hong Nie
Keyword(s):  
Differential Geometry ◽  
Control Algorithm ◽  
Active Suspension ◽  
Suspension System ◽  
Decoupling Control ◽  
Vehicle Suspension ◽  
Full Vehicle ◽  
Vibration Attenuation ◽  
Magneto Rheological ◽  
Suspension Model

Vehicle suspension is a MIMO coupling nonlinear system; its vibration couples that of the tires. When magneto-rheological dampers are adopted to attenuate vibration of the sprung mass, the damping forces of the dampers need to be distributed. For the suspension without decoupling, the vibration attenuation is difficult to be controlled precisely. In order to attenuate the vibration of the vehicle effectively, a nonlinear full vehicle semi-active suspension model is proposed. Considering the realization of the control of magneto-rheological dampers, a hysteretic polynomial damper model is adopted. A differential geometry approach is used to decouple the nonlinear suspension system, so that the wheels and sprung mass become independent linear subsystems and independent to each other. A control rule of vibration attenuation is designed, by which the control current applied to the magneto-rheological damper is calculated, and used for the decoupled suspension system. The simulations show that the acceleration of the sprung mass is attenuated greatly, which indicates that the control algorithm is effective and the hysteretic polynomial damper model is practicable.

HDD Slider Air Bearing Design Optimization Using a Surrogate Model

2005 ◽  
Author(s):  
Naozumi Tsuda ◽  
David B. Bogy
Keyword(s):  
Convergence Rate ◽  
Cost Function ◽  
Surrogate Model ◽  
Search Space ◽  
Kriging Model ◽  
Flying Height ◽  
Direct Algorithm ◽  
Air Bearing ◽  
High Convergence Rate ◽  
Sampling Points

This report addresses a new optimization method in which the DIRECT algorithm is used in conjunction with a surrogate model. The DIRECT algorithm itself can find the global optimum with a high convergence rate. However the convergence rate can be much improved by coupling DIRECT with a surrogate model. The surrogate model known as the Kriging model is used in this research. It is determined by using sampling points generated by the DIRECT algorithm. This model expresses the shape of a hyper surface approximation of the cost function over the entire search space. Finding the optimum point on this hyper surface is very fast because it is not necessary to solve the time consuming air bearing equations. By using this optimum candidate as one of the DIRECT sampling points, we can eliminate many cost function evaluations. To illustrate the power of this approach we first present some simple optimization examples using known difficult functions. Then we determine the optimum design of a slider with 5nm flying height (FH) starting with a design that has a 7nm FH.

Influence of suspension hysteresis characteristics on vehicle vibration performance

2020 ◽  
pp. 095440702097083
Author(s):  
Zhifei WU ◽  
Yuxia Xiang ◽  
Chenggui Liu
Keyword(s):  
Maxwell Model ◽  
Nonlinear Damping ◽  
Suspension System ◽  
Vehicle Body ◽  
Leaf Spring ◽  
Full Vehicle ◽  
Nonlinear Hysteresis ◽  
Suspension Model ◽  
Vibration Performance ◽  
Hysteresis Characteristics

To analyze the influence of the leaf spring hysteresis characteristics on the vehicle body vibration performance, it is necessary to take the physical nonlinear factors into account in the suspension dynamic modeling analysis. The hysteresis characteristics of the leaf spring are caused by the contact and friction between the spring pieces. Besides that, the damping elements of the suspension system are also strongly nonlinear. And hence this article presents a generalized Maxwell-slip damper (GMD) model, which can represent the general hysteresis characteristics of the suspension system. The GMD model incorporates spring stiffness and nonlinear damping in addition to spring friction using the Maxwell model. Then the effects of various parameters on the hysteresis characteristics of GMD model are analyzed and verified by simulation and bench experiments. In addition, an eight degree of freedom (8-DOF) full vehicle model capturing some frictional characteristics was established to study vehicle vibration performance under random road excitation. At the same time, the actual vehicle test is conducted under different road conditions. Ultimately, the results of the nonlinear suspension model have a reasonable agreement with the experimental results, which further demonstrates the credibility of the proposed GMD model. That is, the full vehicle dynamic model with friction force is entirely accurate and useful. The proposed nonlinear hysteresis model may be instructive for accessing the vehicle vibration response to further study the direct effects of friction on vehicle handling and driver feedback.

Semi-Active Suspension System for 2S1 Tracked Platform in Application of Improvement of the Vehicle Body Stability

2015 ◽  
Vol 759 ◽  
pp. 77-90 ◽  
Author(s):  
Tomasz Nabagło ◽  
Andrzej Jurkiewicz ◽  
Janusz Kowal
Keyword(s):  
Active Suspension ◽  
Suspension System ◽  
Comfort Level ◽  
Vehicle Body ◽  
Active Suspensions ◽  
Basic Model ◽  
Strategy Model ◽  
Ground Conditions ◽  
Suspension Model ◽  
Torsion Springs

In the article, a new solution of a semi-active suspension system is presented. It is based on a sky-hook strategy model. This solution in 2S1 tracked platform is applied to improve body vehicle stability and driving comfort. The solution is applied in two versions of the 2S1 vehicle suspension model. First one is a basic model. This suspension is based on existing construction of the 2S1 platform suspension. It is based on torsion bars. Second one is a modified model, based on spiral torsion springs. In this model a new solution of idler mechanism is applied. It provides constant tension of the tracks. Semi-active suspensions simulations results are compared with results of models with passive versions of the suspension to highlight the improvement level. Simulations are conducted in the Yuma Proving Ground conditions. Results of all models simulations are compared and analyzed to improve stability and comfort level in conditions of the modern battlefield. Stability level is analyzed for weapon aiming tasks. Comfort level is analyzed for the vehicle crew efficiency.

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