scholarly journals Topology Synthesis of Compliant Systems With Embedded Actuators and Sensors

2008 ◽  
Author(s):  
Brian Trease ◽  
Sridhar Kota
Keyword(s):  
Adaptive Systems ◽  
Compliant Mechanisms ◽  
Single Point ◽  
Sensor Placement ◽  
System Response ◽  
Structural Topology ◽  
Force Transmission ◽  
Basic Premise ◽  
Starting Point ◽  
Compliant Systems

The basic premise of a compliant system is the integration of motion/force transmission via elastic deformation with embedded actuation and sensing. Current electromechanical systems are generally fashioned in the rigid-and-discrete paradigm where one first designs a rigid structure with mechanical joints and then adds actuators and sensors, with the design of controls only following as an afterthought. The objective of this research is a systems approach to synthesis of mechanism, structure, actuation, and sensing, thereby advancing from traditional mechanical design to automated compliant system design. In previous studies of compliant mechanisms and their synthesis, single-actuator mechanisms have primarily been considered, with the determination of the actuator’s type, orientation, size, and location occurring outside of the automated design synthesis, at the designer’s option. A new algorithmic framework is presented, in which structural topology and actuator/sensor placement are simultaneously synthesized for adaptive performance. Significantly, this is not a traditional ad hoc method; sensor and actuator placement affect structural topology and vice versa. This is a continuation of our previously reported actuation-placement work [1–2], updated here to include the sensor placement co-synthesis and new tasks in addition to shape change. The methods used include genetic algorithms, graph searches for connectivity, and multiple load cases implemented with linear finite element analysis. Fundamental metrics for the inclusion of embedded components in a multifunctional compliant system are developed and investigated. The essential framework for the integration of controls with compliant mechanisms is established. Specifically, the concepts of controllability and observability, as redefined for compliant systems, are proven as a successful starting point for the design of multifunctional, adaptive systems. These concepts refer to the unique system response for each component (actuator or sensor) it contains. Results are presented for several problems, focusing on the application of shape-morphing aircraft structures. Through examples and design studies, the metrics and the methodology demonstrate that multiple, optimally-placed components indeed offer performance benefits for mechanical systems, in terms of multifunctional execution. Finally, the extension of controllability to address the problem of single-point multidegree-of-freedom manipulation is performed to show the generalized use of the new methodology in benefitting the design of compliant systems.

Design of Adaptive and Controllable Compliant Systems With Embedded Actuators and Sensors

2009 ◽  
Vol 131 (11) ◽  
Author(s):  
Brian Trease ◽  
Sridhar Kota
Keyword(s):  
Compliant Mechanism ◽  
Systems Design ◽  
Maximum Energy ◽  
Topology Design ◽  
Simultaneous Optimization ◽  
System Response ◽  
Structural Topology ◽  
Element Analysis ◽  
Active Structure ◽  
Compliant Systems

We present a framework for the design of a compliant system, i.e., the concurrent design of a compliant mechanism with embedded actuators and sensors. Our methods simultaneously synthesize optimal structural topology and component placement for maximum energy efficiency and adaptive performance, while satisfying various weight and performance constraints. The goal of this research is to lay an algorithmic framework for distributed actuation and sensing within a compliant active structure. Key features of the methodology include (1) the simultaneous optimization of the location, orientation, and size of actuators (and sensors) concurrent with the compliant transmission topology, and (2) the implementation of controllability and observability concepts (both arising from consideration of control) in compliant systems design. The methods used include genetic algorithms, graph searches for connectivity, and multiple load cases implemented with linear finite element analysis. Actuators, modeled as both force generators and structural compliant elements, are included as topology variables in the optimization. The results from the controllability problem are used to motivate and describe the analogous extension to observability for sensing. Results are provided for several studies, including (1) concurrent actuator placement and topology design for a compliant amplifier, (2) a shape-morphing aircraft wing demonstration with three controlled output nodes, and (3) a load-distribution sensing wing structure with internal sensors. Central to this method is the concept of structure/component orthogonality, which refers to the unique system response for each component (actuator or sensor) it contains.

Synthesis of Adaptive and Controllable Compliant Systems With Embedded Actuators and Sensors

2006 ◽  
Author(s):  
Brian P. Trease ◽  
Sridhar Kota
Keyword(s):  
Compliant Mechanism ◽  
Systems Design ◽  
Maximum Energy ◽  
Topology Design ◽  
Simultaneous Optimization ◽  
System Response ◽  
Mathematical Framework ◽  
Structural Topology ◽  
Element Analysis ◽  
Compliant Systems

This paper presents a framework for the design of a compliant system; that is, the concurrent design of a compliant mechanism with embedded actuators and embedded sensors. We focus on methods that simultaneously synthesize optimal structural topology and placement of actuators and sensors for maximum energy efficiency and adaptive performance, while satisfying various weight and performance constraints. The goal of this research is to lay a scientific foundation and a mathematical framework for distributed actuation and sensing within a compliant active structure. Key features of the methodology include (1) the simultaneous optimization of the location, orientation, and size of actuators concurrent with the compliant transmission topology and (2) the concepts of controllability and observability that arise from the consideration of control, and their implementation in compliant systems design. The methods used include genetic algorithms, graph searches for connectivity, and multiple load cases implemented with linear finite element analysis. Actuators, modeled as both force generators and structural compliant elements, are included as topology variables in the optimization. Results are provided for several studies, including: (1) concurrent actuator placement and topology design for a compliant amplifier and (2) a shape-morphing aircraft wing demonstration with three controlled output nodes. Central to this method is the concept of structural orthogonality, which refers to the unique system response for each actuator it contains. Finally, the results from the controllability problem are used to motivate and describe the analogous extension to observability for sensing.

Design of 2-DOF Compliant Mechanisms to Form Grip-and-Move Manipulators for 2D Workspace

2010 ◽  
Vol 132 (3) ◽  
Author(s):  
N. F. Wang ◽  
K. Tai
Keyword(s):  
Degrees Of Freedom ◽  
Optimization Problem ◽  
Compliant Mechanisms ◽  
Nonlinear Finite Element ◽  
Optimal Designs ◽  
Structural Topology ◽  
Structural Geometry ◽  
Multiobjective Genetic Algorithm ◽  
Topology And Shape Optimization ◽  
Morphological Representation

This paper demonstrates the design of compliant grip-and-move manipulators by structural optimization using genetic algorithms. The manipulator is composed of two compliant mechanisms (each with two degrees of freedom) that work like two fingers so that the manipulator can grip an object and convey it from one point to another anywhere within a two-dimensional workspace. The synthesis of such compliant mechanisms is accomplished by formulating the problem as a structural topology and shape optimization problem with multiple objectives and constraints to achieve the desired behavior of the manipulator. A multiobjective genetic algorithm is then applied coupled with an enhanced morphological representation for defining and encoding the structural geometry variables. The solution framework is integrated with a nonlinear finite element code for large-displacement analyses of the compliant structures to compute the paths generated by these mechanisms, with the resulting optimal designs used to realize various manipulator configurations.

scholarly journals An Accelerating Convergence Rate Method for Moving Morphable Components

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Ruichao Lian ◽  
Shikai Jing ◽  
Zhijun He ◽  
Zefang Shi ◽  
Guohua Song
Keyword(s):  
Convergence Rate ◽  
Three Dimensional ◽  
Structural Topology ◽  
Coarse Mesh ◽  
Starting Point ◽  
Good Starting Point ◽  
Topological Configuration ◽  
Rate Method ◽  
The Stability ◽  
Moving Morphable Components

In the structural topology optimization approaches, the Moving Morphable Components (MMC) is a new method to obtain the optimized structural topologies by optimizing shapes, sizes, and locations of components. However, the size of the mesh has a strong influence on the rate of which the component builds the initial topological configuration by moving. The influence may slow down the convergence rate. In this paper, a hierarchical mesh subdivision solution method that can accelerate the convergence rate for the MMC is developed. First, the coarse mesh is used as the starting point for the optimization problem, and the construction process of the initial topology structure is increased speed by accelerating the movement of components. Second, the optimized solution obtained by the coarse mesh is equivalently mapped to the same problem with a finer mesh and used to construct a good starting point for the next optimization. Finally, two-dimensional (2D) MBB beam example and three-dimensional (3D) short cantilever beam example are provided so as to validate that with the use of the proposed approach, demonstrating that this method can improve the convergence rate and the stability of the MMC method.

Positioning Against Other Theories

2010 ◽  
pp. 135-161
Author(s):  
Lars Taxén
Keyword(s):  
Strategic Management ◽  
Complex Adaptive Systems ◽  
Adaptive Systems ◽  
Research Area ◽  
Organizational Research ◽  
Complex Systems Theory ◽  
Turbulent Environments ◽  
Starting Point ◽  
Complex Adaptive

Complex systems theory (e.g. Bar-Yam, 1997) is a rich and vital research area that has a huge potential for organizational research (Lewin, 1999). In particular, the study of complex adaptive systems (CASs) provides many insightful results concerning the adaptability and strategic management of organizations in turbulent environments (ibid). In the following, I will take this characterization of CASs as a starting point for exploring possible connections between CAS and ADT. This is done against the background of the previously reported complexity inherent in both telecom systems and projects developing these systems.

Lightweight Design of a Brake Caliper

2013 ◽  
Author(s):  
Federico Maria Ballo ◽  
Massimiliano Gobbi ◽  
Giampiero Mastinu ◽  
Amir Pishdad
Keyword(s):  
Cross Sections ◽  
Lightweight Design ◽  
Optimal Solution ◽  
Element Model ◽  
Industrial Applications ◽  
Structural Topology ◽  
Multi Objective Optimization ◽  
Multi Objective ◽  
Beam Elements ◽  
Starting Point

As lightweight design assumes greater importance in road vehicles development, the present paper is mainly devoted to the structural optimization of a brake caliper. In the first part of the study a simplified finite element model based on beam elements of a brake caliper has been developed and validated. By using the developed model, a multi-objective optimization has been completed. The total mass of the caliper and the deformations at some critical locations have been minimised. The considered design variables are related to the shape of the caliper and the cross sections of the beam elements. The obtained optimal solutions are characterized by an asymmetric shape of the caliper. Optimised symmetric shapes currently used have been compared with the asymmetric ones in terms of performance. In the second part of the study, a detailed analysis on the optimal caliper shape has been carried out by performing a structural topology optimization. The minimum compliance problem has been solved using the SIMP (solid isotropic material with penalization) approach and the optimal solution has been compared with the ones obtained by applying the multi-objective optimization on the simplified model (beam elements). The obtained design solutions represent a good starting point for future developments in actual industrial applications.

Nonlinear Aeroelastic Study of Bending Divergence

2010 ◽  
Author(s):  
Ghalib Y. Thwapiah ◽  
L. Flavio Campanile
Keyword(s):  
Large Deformations ◽  
Wind Tunnel Test ◽  
Experimental Tests ◽  
Research Trend ◽  
System Response ◽  
History Of ◽  
Compliant Systems ◽  
New Research ◽  
Wing Morphing ◽  
In The Beginning

In the beginning of the history of aviation, aeroelastic static instabilities were a problem in operating monoplane aircraft. After being discovered, they have been systematically avoided by design, since they would have led to large deformations and structural failure. A new research trend (active aeroelasticity) reverts this approach and utilizes — instead of avoiding — static instabilities to realize wing morphing. Another modern research trend are compliant systems (i.e. structures designed to achieve large deformations within its elastic range). Joining those two trends lead to a novel class of airfoil structures (compliant, active aeroelastic wings) enables operating at and beyond aeroelastic instabilities. Such structures need a new modeling approach, which includes nonlinearities of structural and aerodynamic kind. In this paper, a non linear analysis of aeroelastic bending divergence (a phenomenon which concerns forward-swept wings) is presented, initially based on so-called low-fidelity models. Such models are to some extent inaccurate, but allow a good insight into the physical behavior of the phenomenon. Experimental tests of a compliant airfoil will then be presented, performed to investigate the trans-critical and post-critical response of the airfoil model and to validate the low fidelity models. At the end, high-fidelity modeling is approached, which makes use of computational numerical simulations methods (FEM, CFD, FSI). Selected results will be presented, which allow to predict the system response more accurately and to reproduce the wind tunnel test results more closely.

Two Stage Design of Compliant Mechanisms With Superelastic Compliant Joints

2017 ◽  
Author(s):  
Jovana Jovanova ◽  
Mary Frecker
Keyword(s):  
Analytical Model ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Functionally Graded ◽  
Two Stage ◽  
Stage Design ◽  
Rigid Link ◽  
Starting Point ◽  
Single Piece ◽  
Two Stage Design

The design of compliant mechanisms made of Nickel Titanium (NiTi) Shape Memory Alloys (SMAs) is considered to exploit the superelastic behavior of the material to achieve tailored high flexibility on demand. This paper focuses on two-stage design optimization of compliant mechanisms, as a systematic method for design of the composition of the functionally graded NiTi material within the compliant mechanism devices. The location, as well as geometric and mechanical properties, of zones of high and low flexibility will be selected to maximize mechanical performance. The proposed two-stage optimization procedure combines the optimization of an analytical model of a single-piece functionally graded unit, with a detailed FEA of a continuous compliant mechanism. In the first stage, a rigid-link model is developed to initially approximate the behavior of the compliant mechanism. In the second stage the solution of the rigid-link problem serves as the starting point for a continuous analytical model where the mechanism consists of zones with different material properties and geometry, followed by a detailed FEA of a compliant mechanism with integrated zones of superelasticity. The two-stage optimization is a systematic approach for compliant mechanism design with functional grading of the material to exploit superelastic response in controlled manner. Direct energy deposition, as an additive manufacturing technology, is foreseen to fabricate assemblies with multiple single piece functional graded components. This method could be applied to bio-inspired structures, flapping wings, flexible adaptive structures and origami inspired compliant mechanisms.

scholarly journals Synthesis of Multi-Protein Complexes through Charge-Directed Sequential Activation of Tyrosine Residues

2021 ◽  
Author(s):  
Casey S. Mogilevsky ◽  
Marco Lobba ◽  
Daniel D. Brauer ◽  
Alan Marmelstein ◽  
Johnathan Maza ◽  
...  
Keyword(s):  
Protein Design ◽  
Protein Complexes ◽  
Single Point ◽  
Tyrosine Residues ◽  
Starting Point ◽  
Sequential Activation ◽  
Substrate Tolerance ◽  
A Charge ◽  
Site Selective ◽  
Biology Research

Site-selective protein-protein coupling has long been a goal of chemical biology research. In recent years, that goal has been realized to varying degrees through a number of techniques, including the use of tyrosinase-based coupling strategies. Early publications utilizing tyrosinase from <i>Agaricus bisporus</i> showed the potential to convert tyrosine residues into <i>ortho</i>-quinone functional groups, but this enzyme is challenging to produce recombinantly and suffers from some limitations in substrate scope. Initial screens of several tyrosinase candidates revealed that the tyrosinase from <i>Bacillus megaterium</i> (megaTYR) as an enzyme that possesses a broad substrate tolerance. We use the expanded substrate preference as a starting point for protein design experiments and show that single point mutants of megaTYR are capable of activating tyrosine residues in various sequence contexts. We leverage this new tool to enable the construction of protein trimers via a charge-directed sequential activation of tyrosine residues (CDSAT).

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