Parametric Studies of Photo Deformation and Optical Actuation

1995 ◽  
Author(s):  
H. S. Tzou ◽  
C.-S. Chou
Keyword(s):  
Piezoelectric Effect ◽  
Photovoltaic Effect ◽  
Constitutive Relations ◽  
Design Parameters ◽  
Equivalent Control ◽  
Parametric Studies ◽  
Control Forces ◽  
And Control ◽  
Converse Piezoelectric Effect ◽  
Piezoelectric Characteristics

Abstract Optically driven actuators can introduce remote actuation and control effects without any hard-wire connections. In this study, photostrictive {opto-piezoelectric) characteristics and photodeformation of distributed photostrictive optical actuators are investigated and a parametric study of design parameters is conducted. Photodeformation induced by the photostrictive (opto-piezoelectric) effect (a combination of the photovoltaic effect and the converse piezoelectric effect) is discussed and its two-dimensional (2-D) constitutive relations are presented. 2-D equivalent control forces and moments induced by the photodeformation effect of distributed actuators are formulated, and system governing equations derived. Static and dynamic applications are discussed, and simulation studies of design parameters are conducted and evaluated.

Non Contact Precision Actuation and Optimal Actuator Placement of Hybrid Photostrictive Beam Structronic Systems

2007 ◽  
Author(s):  
Hong-Hao Yue ◽  
Zong-Quan Deng ◽  
Horn-Sen Tzou
Keyword(s):  
Photovoltaic Effect ◽  
Mechanical Strain ◽  
Elastic Beam ◽  
High Energy ◽  
Design Parameters ◽  
Control Electronics ◽  
Control Forces ◽  
And Control ◽  
Converse Piezoelectric Effect ◽  
Photostrictive Actuators

Non-contact wireless actuation offers many advantages to precision control, as compared with conventional hard-wired actuation mechanisms. High-energy laser or ultraviolet lights irradiating on photostrictive materials can induce a photodeformation process involving two fundamental effects: 1) the photovoltaic effect and 2) the converse piezoelectric effect. This photodeformation process transforms photonic energy to mechanical strain/stress that can be directly used for actuation and control applications. With specific design configurations, the photodeformation process of photostrictive actuators can induce various control forces and moments applied to precision manipulation and control of mechatronic and structronic systems. In this study, fundamental photodeformation coupling mechanisms among photo-thermo-electromechanical/control fields are investigated and parametric evaluation of various design parameters of a hybrid photostrictive/elastic beam is conducted. A mathematical model for a laminated beam with segmented photostrictive actuators is defined, followed by photodeformation induced modal control forces and moments of segmented actuators. Characteristics of actuation and control effectiveness of distributed photostrictive actuators at various locations, natural modes and illumination intensities are analyzed in case studies. The most effective actuator location(s) for controlling the first four beam modes are illustrated. Finally, with scheduling light irradiations on various photostrictive actuators, one can control multiple beam modes, allowed by control electronics and material response.

Micro-Structronics and Control of Hybrid Electrostrictive/Piezoelectric Thin Shells

Aerospace ◽  
2003 ◽  
Author(s):  
W. K. Chai ◽  
H. S. Tzou ◽  
S. M. Arnold
Keyword(s):  
Curie Point ◽  
Piezoelectric Materials ◽  
Constitutive Relations ◽  
Ferroelectric Materials ◽  
Polar Phase ◽  
Free Energy Function ◽  
Generic Theory ◽  
And Control ◽  
Electrostrictive Effect ◽  
Piezoelectric Characteristics

Certain ferroelectric materials possess dual electrostrictive and piezoelectric characteristics, depending on their specific Curie temperatures. These materials exhibit piezoelectric characteristics in the ferroelectric phase when the temperature is below the Curie point. However, they become electrostrictive in the paraelectric phase (non-polar phase) as the temperature exceeds the Curie point. The (direct) electrostrictive effect is a quadratic dependence of stress or strain on applied electric field. The nonlinear electromechanical effect of electrostrictive materials provides stronger actuation performance as compared with that of piezoelectric materials. Due to the complexity of the generic ferroelectric actuators, micro-electromechanics and control characteristics of generic electrostrictive/piezoelectric dynamics system deserve an in-depth investigation. In this study, electro-mechanical dynamic system equations and generic boundary conditions of hybrid electrostrictive/piezoelectric double-curvature shell continua are derived using the energy-based Hamilton’s principle, elasticity theory, electrostrictive/piezoelectric constitutive relations, and Gibb’s free energy function. Moreover, the second converse electrostrictive effect and the direct piezoelectric effect are all considered in the generic governing equations. Simplifications of the generic theory to other common geometries or specific materials are demonstrated and their electromechanical characteristics are also evaluated.

Actuator Placement and Micro-Actuation Efficiency of Adaptive Paraboloidal Shells

2003 ◽  
Vol 125 (4) ◽  
pp. 577-584 ◽  
Author(s):  
H. S. Tzou ◽  
J. H. Ding
Keyword(s):  
Communication Systems ◽  
Design Parameters ◽  
Shells Of Revolution ◽  
Control Effect ◽  
Control Effectiveness ◽  
Membrane Bending ◽  
High Control ◽  
Control Forces ◽  
And Control ◽  
Actuator Placement

Paraboloidal shells of revolution are commonly used in communication systems, precision opto-mechanical systems and aerospace structures. This study is to investigate the precision distributed control effectiveness of adaptive paraboloidal shells laminated with segmented actuator patches. Mathematical models of the paraboloidal shells laminated with distributed actuator layers subjected to mechanical, temperature, and control forces are presented first. Then, formulations of distributed actuating forces with their contributing micro-meridional/circumferential membrane and bending components are derived using an assumed mode shape function. Studies of actuator placements, actuator induced control forces, micro-contributing components, and normalized actuation authorities of paraboloidal shells are carried out. These forces and membrane/bending components basically exhibit distinct modal characteristics influenced by shell geometries and other design parameters. Analyses suggest that the membrane-contributed components dominate the overall control effect. Locations with larger normalized forces indicate the areas with high control efficiencies, i.e., larger induced actuation force per unit actuator area. With limited actuators, placing actuators at those locations would lead to the maximal control effects of paraboloidal shells.

Experimental Investigation on the Use of Photostrictive Optical Actuator for MEMS Devices and Verification With the FEA Modeling Results

2011 ◽  
Author(s):  
Mosfequr Rahman ◽  
Masud Nawaz ◽  
John E. Jackson
Keyword(s):  
Thin Film ◽  
Lead Zirconate Titanate ◽  
Piezoelectric Effect ◽  
Photovoltaic Effect ◽  
Research Work ◽  
High Energy ◽  
Ferroelectric Ceramics ◽  
Control Signals ◽  
Fea Modeling ◽  
Converse Piezoelectric Effect

Photostrictive materials are lanthanum-modified lead zirconate titanate (Pb, La)(Zr, Ti) O3 ceramics doped with WO3, called PLZT, exhibit large photostriction under uniform illumination of high-energy light. Photostrictive materials are ferrodielectric ceramics that have a photostrictive effect. Photostriction arises from a superposition of the photovoltaic effect, i.e. the generation of large voltage from the irradiation of light, and the converse-piezoelectric effect, i.e. expansion or contraction under the voltage applied. When non-centrosymmetric materials, such as ferroelectric single crystals or polarized ferroelectric ceramics, are uniformly illuminated, a high voltage, considerably exceeding the band gap energy, is generated. Along with this photovoltage, mechanical strain is also induced due to the converse piezoelectric effect. Photostrictive materials offer the potential for actuators with many advantages over traditional transducing electromechanical actuators made of shape memory alloys and electroceramics (piezoelectric and electrostrictive). Drawback of traditional actuators is that they require hard-wired connections to transmit the control signals which introduce electrical noise into the control signals; on the other hand PLZT actuators offer non-contact actuation, remote control, and immune from electric/magnetic disturbances. Some experimental research has been conducted on the use of PLZT materials, such as optical motor as an electromechanical device suitable for miniaturization, micro-waking machine, photo driven relay device using PLZT bimorphs and high speed (less than 10 ns), low-voltage, low power consumption optical switch. Authors have developed a computational method and implemented in an in-house finite element code which will be useful for designing systems incorporating thin film photostrictive actuators. The purpose of this current research work is to design and develop an experimental test set-up for photostriction effect measurement of PLZT thin film of different thickness, size and location on silicon wafer as smart beams, which may be useful for various MEMS device as optical actuator. The experimental results will be verified by comparing with the FEA modeling results.

A New Multi-DOF Photostrictive Actuator for Dynamic Control of Shells: Modeling and Analysis

2008 ◽  
Author(s):  
Hong-Hao Yue ◽  
Gui-Lan Sun ◽  
Zong-Quan Deng ◽  
Horn-Sen Tzou
Keyword(s):  
Lead Zirconate Titanate ◽  
Photovoltaic Effect ◽  
Mechanical Strain ◽  
Dynamic Control ◽  
Lead Zirconate ◽  
Shell Structures ◽  
Control Effect ◽  
And Control ◽  
Converse Piezoelectric Effect ◽  
Distributed Actuator

Based on the photovoltaic effect and the converse piezoelectric effect, the lanthanum-modified lead zirconate titanate (PLZT) actuator can transform the photonic energy to mechanical strain/stress — the photodeformation effect. This photodeformation process can be further used for non-contact precision actuation and control in various structural, biomedical and electromechanical systems. Although there are a number of design configurations of distributed actuators, e.g., segmentation and shaping, been investigated over the years, this study is to explore a new actuator configuration spatially bonded on the surface of shell structures to broaden the spatial modal controllability. A mathematical model of a new multi-degree-of-freedom (DOF) photostrictive actuator configuration is presented first, followed by the photostrictive/shell coupling equations of a cylindrical shell structure laminated with the newly proposed multi-DOF distributed actuator. Distributed microscopic photostrictive actuation and its contributing components are analyzed in the modal domain. Effects of shell’s curvature and actuator’s size are evaluated. Parametric analyses suggest that the new multi-DOF distributed actuator, indeed, provides better performance and control effect to shell actuation and control. This multi-DOF configuration can be further applied to actuation and control of various shell and non-shell structures.

Light-Induced Non-Contact Actuation and Control With Photostrictive Actuators

1997 ◽  
Author(s):  
H. S. Tzou ◽  
B. J. Liu
Keyword(s):  
Constitutive Relations ◽  
Cylindrical Shells ◽  
Time History ◽  
Ultra Violet ◽  
High Energy ◽  
Electromechanical Actuators ◽  
Modeling And Analysis ◽  
Control Effectiveness ◽  
Control Forces ◽  
And Control

Abstract Non-contact light activated distributed opto-electromechanical actuators represent a new class of precision distributed actuator which are based on the photodeformation process and controlled by high energy lights, e.g., lasers and ultra-violet lights. Fundamental opto-thermo-electromechancial constitutive relations are discussed and formulations of optically induced control forces and moments introduced. Mathematical modeling and analysis of distributed opto-electromechanical shell actuators are presented. A generic distributed photo-actuation theory is proposed and the closed-loop opto-thermo-electromechancial equations of circular cylindrical shells are derived. The systems equations reveal the couplings among elasticity, photodeformation, pyroelectricity, and thermoelasticity. Active distributed control of flexible cylindrical shells using segmented distributed opto-electromechanical shell actuators are investigated and the control effectiveness is evaluated. Membrane and bending control effects are evaluated. Time history analyses of independent modal control reveal that the Lyapunov control is more effective than the proportional feedback control.

Actuator Placement and Control Efficiency of Paraboloidal Shell Structures

2001 ◽  
Author(s):  
H. S. Tzou ◽  
J. H. Ding
Keyword(s):  
Distributed Control ◽  
Communication Systems ◽  
Design Parameters ◽  
Control Force ◽  
Shells Of Revolution ◽  
Control Effect ◽  
Membrane Bending ◽  
High Control ◽  
Control Forces ◽  
And Control

Abstract Paraboloidal shells of revolution are commonly used in communication systems, precision opto-mechanical systems and aerospace structures. This study is to investigate the precision distributed control effectiveness of paraboloidal shells laminated with segmented actuator patches. Mathematical models of the paraboloidal shells laminated with distributed actuator layers subjected to mechanical, temperature, and control forces are presented first, followed by formulations of distributed control forces with their contributing meridional/circumferential membrane and bending control components using an assumed mode shape function. Studies of actuator placements, control forces, contributing components, and normalized control authorities of paraboloidal shells are carried out. These forces and membrane/bending components basically exhibit distinct modal characteristics influenced by shell geometries and other design parameters. Analyses suggest that the membrane contributed components dominate the overall control effect. Locations with larger normalized forces indicate the areas with high control efficiencies, i.e., larger induced control force per unit actuator area. With limited actuators, placing actuators at those locations would lead to the maximal control effects.

The Implementation of Learning Materials Based on Local Wisdom of Agricultural in Binjai to Improve the Students Problem Solving Abilities

2019 ◽  
Author(s):  
Nur Tsalits Fahman Mughni
Keyword(s):  
Problem Solving ◽  
Control Group ◽  
School Grade ◽  
Teaching Materials ◽  
Quasi Experimental ◽  
Equivalent Control ◽  
The Subject ◽  
And Control ◽  
Experimental Group

Teaching materials by integrating local culture makes easier for students to understand the subject matter in the learning process. The aims of the study is to measure the effectiveness of teaching materials based on local wisdom of agriculture in Binjai in improving the students problem solving abilities. The research method was a quasi experimental which use non equivalent control group in the pretest posttest design. The sample of study were students of Senior High School grade X in Binjai that consisted of experiment group which used teaching materials based on local wisdom of agriculture in Binjai and control group that used student handbooks. Teaching materials are tested by material experts and technology experts to ensure the quality of teaching materials. Data collection was conducted through test. The results showed that the teaching materials based on local wisdom of agriculture in Binjai effective in improving students problem solving abilities in the experimental group students based on the results of N gain value was 0.67 which has medium criteria. It means teaching materials based on agricultural local wisdom of agriculture in Binjai can be used as one of the teaching materials in learning activities.

scholarly journals Closed-form time derivatives of the equations of motion of rigid body systems

2021 ◽  
Author(s):  
Andreas Müller ◽  
Shivesh Kumar
Keyword(s):  
Rigid Body ◽  
Closed Form ◽  
Multibody Systems ◽  
Equations Of Motion ◽  
Alternative Formulation ◽  
Dynamics Of Rigid Body ◽  
Control Forces ◽  
And Control ◽  
Derivatives Of ◽  
Insight Into

AbstractDerivatives of equations of motion (EOM) describing the dynamics of rigid body systems are becoming increasingly relevant for the robotics community and find many applications in design and control of robotic systems. Controlling robots, and multibody systems comprising elastic components in particular, not only requires smooth trajectories but also the time derivatives of the control forces/torques, hence of the EOM. This paper presents the time derivatives of the EOM in closed form up to second-order as an alternative formulation to the existing recursive algorithms for this purpose, which provides a direct insight into the structure of the derivatives. The Lie group formulation for rigid body systems is used giving rise to very compact and easily parameterized equations.

Parameter Normalization in Multibody Dynamics

2008 ◽  
Author(s):  
Saeed Ebrahimi ◽  
Jo´zsef Ko¨vecses
Keyword(s):  
Parameter Estimation ◽  
Multibody Dynamics ◽  
Eigenvalue Problems ◽  
Physical Structure ◽  
Control Problems ◽  
Inertial Parameters ◽  
Parametric Studies ◽  
Novel Concept ◽  
And Control

In this paper, we introduce a novel concept for parametric studies in multibody dynamics. This is based on a technique that makes it possible to perform a natural normalization of the dynamics in terms of inertial parameters. This normalization technique rises out from the underlying physical structure of the system, which is mathematically expressed in the form of eigenvalue problems. It leads to the introduction of the concept of dimensionless inertial parameters. This, in turn, makes the decomposition of the array of parameters possible for studying design and control problems where parameter estimation and sensitivity is of importance.

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