scholarly journals Optimization of a Piezoelectric Bending Actuator for a Tactile Virtual Reality Display

2015 ◽  
Vol 2 (3-4) ◽  
pp. 177-185
Author(s):  
Viktor Hofmann ◽  
Jens Twiefel
Keyword(s):  
Beam Theory ◽  
Normal Direction ◽  
Tactile Display ◽  
Rotational Degree ◽  
Shear Forces ◽  
Display Design ◽  
Bending Actuator ◽  
High Dynamic ◽  
Actuator Design ◽  
Method Model

Abstract The excitation of mechanoreceptors in the finger with different frequencies and intensities generates a tactile impression. For the experience of a complete surface many distributed sources are needed in the tactile display. For these local stimulations of the finger several piezoelectric bending actuators will be arranged in an array perpendicular to the skin. The challenge in the system design is to transfer high dynamic shear forces to the skin at required frequencies together with a compact display design. In order to estimate the dynamic behavior of the bending actuators a transfer matrix method model based on the Timoshenko beam theory is derived. Beside the outer geometric values, the layered structure of the actuator is included in the model. In addition the influence of the load on the actuator’s tip in lateral and in normal direction as well as on the rotational degree of freedom is taken into account. Using the analytical approach, a parametric study is carried out to find an optimized actuator design for the display. For the validation, the modeled beam is compared with experimental data.

scholarly journals Non uniform warping for beams

2008 ◽  
pp. 933-944
Author(s):  
Rached El Fatmi
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Beam Theory ◽  
Elastic Behavior ◽  
Cantilever Beams ◽  
Shear Forces ◽  
One Dimensional ◽  
The One ◽  
Displacement Model ◽  
Shear Bending

A non-uniform warping beam theory including the effects of torsion and shear forces is presented. Based on a displacement model using three warping parameters associated to the three St Venant warping functions corresponding to torsion and shear forces, this theory is free from the classical assumptions on the warpings or on the shears, and valid for any kind of homogeneous elastic and isotropic cross-section. This general theory is applied to analyze, for a representative set of cross-sections, the elastic behavior of cantilever beams subjected to torsion or shear-bending. Numerical results are given for the one-dimensional structural behavior and the three-dimensional stresses distributions; for the stresses in the critical region of the built-in section, comparisons with three-dimensional finite elements computations are presented. The study clearly shows when the effect of the restrained warping is localized or not.

High-frequency robust position control of a nonlinear piezoelectric bending actuator

2020 ◽  
Vol 26 (17-18) ◽  
pp. 1560-1573 ◽  
Author(s):  
Pouyan Shahabi ◽  
Hamed Ghafarirad ◽  
Afshin Taghvaeipour
Keyword(s):  
High Frequency ◽  
Position Control ◽  
Tracking Error ◽  
Beam Theory ◽  
Cell Manipulation ◽  
Average Error ◽  
Position Tracking ◽  
Nonlinear Dynamic Model ◽  
Low Frequencies ◽  
Bending Actuator

Piezoelectric bending actuators have been widely used in a variety of micro- and nano-applications, including atomic force microscopy, micro assembly, cell manipulation, and in general, micro electromechanical systems. However, their control algorithms at low frequencies suffer from nonlinearities such as hysteresis in high voltages and creep in long-time static applications. Also, in high-frequency applications, especially near the actuator natural frequencies, the actuator dynamic is greatly affected by the material nonlinearity. Therefore, the control approaches based on the linear dynamic modeling cannot be effective at high frequencies. Thus, the position control of the foregoing actuators become challenging, and it has been of researchers’ interests in the last decade. In this article, the robust position control of a bimorph piezoelectric bending actuators is investigated. In this regard, based on the nonlinear constitutive equations and the Euler–Bernoulli beam theory, a nonlinear dynamic model is presented. Then, to track a desired motion trajectory, an observer-based robust position control algorithm is proposed. The proposed control methodology is able to accommodate parametric uncertainties and other un-modeled dynamics. Also, it ensures the elimination of the position tracking error in the presence of the estimated states. Finally, the tracking ability of the controller is demonstrated in an experimental study. The experimental results show that the identification of the system is properly conducted with the average error of 5.5%. Also, the efficiency of the robust controller is proved with the error of 3.7% and 4.9% in the position tracking of the actuator inside and outside of the identified region, respectively.

When Content Matters: The Role of Processing Code in Tactile Display Design

2010 ◽  
Vol 3 (3) ◽  
pp. 199-210 ◽  
Author(s):  
Thomas K. Ferris ◽  
Nadine Sarter
Keyword(s):  
Tactile Display ◽  
Display Design

scholarly journals Dynamic Amplification Factor of Shear Force on Bridge Columns under Impact Load

2019 ◽  
Vol 2019 ◽  
pp. 1-14 ◽  
Author(s):  
Haiying Ma ◽  
Zhen Cao ◽  
Xuefei Shi ◽  
Junyong Zhou
Keyword(s):  
Amplification Factor ◽  
Impact Load ◽  
Beam Theory ◽  
Dynamic Effect ◽  
Bridge Columns ◽  
Dynamic Amplification Factor ◽  
Shear Forces ◽  
Higher Order Modes ◽  
Bridge Column ◽  
Dynamic Amplification

Shear failure is a common mode for bridge column collapse during a vehicle-column collision. In current design codes, an equivalent static load value is usually employed to specify the shear capacity of bridge columns subject to vehicle collisions. But how to consider the dynamic effect on bridge columns induced by impact load needs further research. The dynamic amplification factor (DAF) is generally used in the analysis and design to include the dynamic effect, which is usually determined using the equivalent single degree of freedom (SDOF) method. However, SDOF method neglects the effect of the higher-order modes, leading to big difference between the calculated results and the real induced forces. Therefore, a novel method to obtain dynamic response under concentrated impact load including the effect of higher-order modes is proposed in the paper, which is based on the modified Timoshenko beam theory (MTB) and the classical Timoshenko beam theory (CTB). Finite element models are conducted to validate the proposed method. The result comparisons show that the results from the proposed method have more accuracy compared with the results from the CTB theory. Additionally, the proposed method is employed to calculate the maximum DAF of shear forces for bridge columns under impact load. Parametric studies are conducted to investigate the effect on the DAF of shear forces including slenderness ratio, boundary condition, and shape and position of impact load. Finally, a simplified formula for calculating the maximum DAF of shear force is proposed for bridge column design.

scholarly journals Revisiting the Perceived Motion Model that Predicted 360 FPS Displays by S Daly 2021

2021 ◽  
Author(s):  
scott daly
Keyword(s):  
Motion Perception ◽  
Human Performance ◽  
Dynamic Range ◽  
High Dynamic Range ◽  
Motion Model ◽  
Display Design ◽  
Free Viewing ◽  
Display Technology ◽  
High Dynamic ◽  
Perceived Motion

A previous model of motion perception used in engineering display design predicted the need for a 360 FPS (frames per second) and 1080-line display and image signal format system, in order to match the viewing of reality. Now that 360 FPS gaming monitors are on the market, the model is revisited with twenty years of new studies, display technology advancements such as HDR (high dynamic range), and inclusion of new viewing tasks such as performance gaming. This revised model is then used to make new predictions for display and signal format requirements to achieve distortion-free viewing of reality and synthetic signals that do not impose limits to human performance.

On the Stresses and Deflections of Rectangular Beams

1956 ◽  
Vol 23 (3) ◽  
pp. 339-342
Author(s):  
B. A. Boley ◽  
I. S. Tolins
Keyword(s):  
Elasticity Theory ◽  
Infinite Series ◽  
Timoshenko Beam ◽  
Iterative Procedure ◽  
Beam Theory ◽  
Timoshenko Beam Theory ◽  
Two Dimensional ◽  
Shear Forces ◽  
Strength Of Materials

Abstract The stresses and deflections in rectangular beams and bars are calculated from the two-dimensional elasticity theory by an iterative procedure previously derived. The loading consists of either normal or shear forces varying smoothly along the span. The results are obtained in the form of infinite series, whose first terms represent the elementary solutions of strength of materials; the accuracy of the Mc/I and P/A formulas can thus be estimated. A comparison with the Timoshenko beam theory is included.

Actuator Array for Display of Distributed Tactile Information: Design and Preliminary Experiments

2000 ◽  
Author(s):  
Peter Kammermeier ◽  
Martin Buss ◽  
Günther Schmidt
Keyword(s):  
Dynamic Interaction ◽  
Information Design ◽  
Tactile Feedback ◽  
Tactile Display ◽  
Parameter Estimates ◽  
Shape Information ◽  
Tactile Information ◽  
Kinesthetic Feedback ◽  
Actuator Design ◽  
Dynamic Shape

Abstract In this paper we present the design of a new tactile actuator array for the display of distributed tactile dynamic shape information in telepresence and Virtual Environment (VE) applications. In actuator design we focussed on high pin forces and a bandwidth sufficient for most one-fingered tactile shape exploration tasks performed by dynamic interaction. As a result, the overall device dimensions currently prohibit its attachment to the effector of typical kinesthetic feedback devices. Experimental results are presented using the prototype in a finger-on-conveyer-belt scenario with objects moving relative to a resting fingertip. Experiments showed that the dynamic tactile display enabled probands to give parameter estimates of displayed objects with an accuracy exceeding the pin resolution of the tactile feedback device.

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