Evaluation and Design of Displacement-Amplifying Compliant Mechanisms for Sensor Applications

2008 ◽  
Vol 130 (10) ◽  
Author(s):  
Girish Krishnan ◽  
G. K. Ananthasuresh
Keyword(s):  
Elastic Body ◽  
Compliant Mechanisms ◽  
Force Sensor ◽  
Optimization Methods ◽  
Size Optimization ◽  
Mass Model ◽  
Sensor Applications ◽  
Capacitive Accelerometer ◽  
Points Of Interest ◽  
Primary Problem

Displacement-amplifying compliant mechanisms (DaCMs) reported in literature are widely used for actuator applications. This paper considers them for sensor applications that rely on displacement measurement, and proposes methods to evaluate and design such mechanisms. The motivation of this work is to increase the sensitivity of a micromachined capacitive accelerometer and a minute mechanical force sensor using DaCMs. A lumped spring-mass-lever (SML) model, which effectively captures the effects of appending a DaCM to a sensor, is introduced. This model is a generalization of the ubiquitously used spring-mass model for the case of an elastic body that has two points of interest—an input and an output. The SML model is shown to be useful in not only evaluating the suitability of an existing DaCM for a new application but also for designing a new DaCM. With the help of this model, we compare a number of DaCMs from literature and identify those that nearly meet the primary problem specifications. To obtain improved designs that also meet the secondary specifications, topology and size-optimization methods are used. For the two applications considered in this paper, we obtain a few new DaCM topologies, which are added to the catalog of DaCMs for future use. The spring-mass-lever model, the evaluation and design methods, and the catalog of DaCMs presented here are useful in other sensor and actuator applications.

An Objective Evaluation of Displacement-Amplifying Compliant Mechanisms for Sensor Applications

2006 ◽  
Author(s):  
Girish Krishnan ◽  
G. K. Ananthasuresh
Keyword(s):  
Natural Frequency ◽  
Compliant Mechanisms ◽  
Selection Procedure ◽  
Force Sensor ◽  
Objective Evaluation ◽  
Performance Criteria ◽  
Sensor Applications ◽  
Capacitive Accelerometer ◽  
General Evaluation

Displacement-amplifying compliant mechanisms (DaCMs) reported in literature are mostly used for actuator applications. This paper considers them for sensor applications that rely on displacement measurement, and evaluates them objectively. The main goal is to increase the sensitivity under constraints imposed by several secondary requirements and practical constraints. A spring-mass-lever model that effectively captures the addition of a DaCM to a sensor is used in comparing eight DaCMs. We observe that they significantly differ in performance criteria such as geometric advantage, stiffness, natural frequency, mode amplification, factor of safety against failure, cross-axis stiffness, etc., but none excel in all. Thus, a combined figure of merit is proposed using which the most suitable DaCM could be selected for a sensor application. A case-study of a micro machined capacitive accelerometer and another case-study of a vision-based force sensor are included to illustrate the general evaluation and selection procedure of DaCMs with specific applications. Some other insights gained with the analysis presented here were the optimum size-scale for a DaCM, the effect on its natural frequency, limits on its stiffness, and working range of the sensor.

scholarly journals Evidence-Theory-Based Robust Optimization and Its Application in Micro-Electromechanical Systems

2019 ◽  
Vol 9 (7) ◽  
pp. 1457 ◽  
Author(s):  
Zhiliang Huang ◽  
Jiaqi Xu ◽  
Tongguang Yang ◽  
Fangyi Li ◽  
Shuguang Deng
Keyword(s):  
Probabilistic Model ◽  
Epistemic Uncertainty ◽  
Evidence Theory ◽  
Robustness Analysis ◽  
Force Sensor ◽  
Image Sensor ◽  
Optimization Approach ◽  
Electromechanical Systems ◽  
Capacitive Accelerometer ◽  
Robustness Optimization

The conventional engineering robustness optimization approach considering uncertainties is generally based on a probabilistic model. However, a probabilistic model faces obstacles when handling problems with epistemic uncertainty. This paper presents an evidence-theory-based robustness optimization (EBRO) model and a corresponding algorithm, which provide a potential computational tool for engineering problems with multi-source uncertainty. An EBRO model with the twin objectives of performance and robustness is formulated by introducing the performance threshold. After providing multiple target belief measures (Bel), the original model is transformed into a series of sub-problems, which are solved by the proposed iterative strategy driving the robustness analysis and the deterministic optimization alternately. The proposed method is applied to three problems of micro-electromechanical systems (MEMS), including a micro-force sensor, an image sensor, and a capacitive accelerometer. In the applications, finite element simulation models and surrogate models are both given. Numerical results show that the proposed method has good engineering practicality due to comprehensive performance in terms of efficiency, accuracy, and convergence.

Research for Rectangular Beam of Dual-E Elastic Body of Six-Axis Force Sensor Based on Limit Memory Extended Kalman Filter

2013 ◽  
Vol 385-386 ◽  
pp. 382-387
Author(s):  
Wen Chao Zhu ◽  
De Zhang Xu
Keyword(s):  
Kalman Filter ◽  
Elastic Body ◽  
Extended Kalman Filter ◽  
Optimal Estimation ◽  
Force Sensor ◽  
Noise Signal ◽  
Current Time ◽  
Rectangular Beam ◽  
State Measurement ◽  
Filtering Effect

The series approximation in the EKF algorithm can lead to low estimated accuracy and poor robustness. To this end, the paper proposes Limit Memory Extended Kalman Filter (LEKF) algorithm which is based on the nonlinear Limited Memory Filter (LMF).Next the paper develops the model of nonlinear state-measurement for rectangular beam of dual-E elastic body of six-axis force sensor by the relationship between strain and deflection. Moreover, The EKF algorithm which is combined with the LMF algorithm can only use the first N-1 measurements that are nearest the current time to compute the optimal estimation. Finally, the effect of old measurements can be reduced substantially. Comparing with the LMF and the EKF in terms of filtering effect by simulation experiments, it is shown that the LEKF algorithm provides higher estimated accuracy and better rubustness to eliminate the noise signal.

The Fair Evaluation of Wave Energy Converters

2020 ◽  
Author(s):  
Jian Tan ◽  
Henk Polinder ◽  
Peter Wellens ◽  
Sape Miedema
Keyword(s):  
Wave Energy ◽  
Evaluation Method ◽  
Control Strategies ◽  
Optimization Methods ◽  
Size Optimization ◽  
Point Absorber ◽  
Wave Energy Converters ◽  
Cost Of Energy ◽  
The Cost ◽  
Energy Converters

Abstract In this paper, a fair evaluation method of WECs (Wave Energy Converters) is established based on frequency domain simulation. In this fair evaluation, size optimization and downsizing of PTO (Power Take-Off) capacity are included to minimize the Cost of Energy for the concerned wave location. Based on this fair evaluation, a techno-economic evaluation of a generic point absorber is conducted for a specific wave location, and two different control strategies of PTO are considered. The results show that this fair evaluation method can contribute to the improvement of techno-economic performance of WECs. Furthermore, a comparison among three different size optimization methods of WECs is performed.

On Optimal Design of Compliant Mechanisms for Specified Nonlinear Path Using Curved Frame Elements and Genetic Algorithm

2006 ◽  
Author(s):  
Ashok Rai ◽  
Anupam Saxena ◽  
Nilesh D. Mankame ◽  
Chandra Shekhar Upadhyay
Keyword(s):  
Genetic Algorithm ◽  
Compliant Mechanisms ◽  
Beam Theory ◽  
Topology Design ◽  
Size Optimization ◽  
Discrete Topology ◽  
Topology Optimization Problem ◽  
Young’S Moduli ◽  
Design Variables ◽  
Out Of Plane

This paper discusses topology, shape and size optimization of fully compliant mechanisms for path generation applications using curved frame elements and genetic algorithm. The topology optimization problem is treated as a discrete ‘0-1’ problem wherein the elastic modulus is chosen as 0 or some pre-specified value, and no intermediate value in between. As the Young’s moduli are discrete topology design variables, function based genetic algorithm is employed for optimization. The size optimization variables are the lengths, in-plane widths and out-of-plane thicknesses of frame elements. Shape optimization is performed using the end slopes. Kirchhoff’s shallow arch beam theory is employed along with co-rotational geometrically nonlinear formulation. Synthesis examples are presented to demonstrate the applicability of min-max criterion proposed to achieve a curved path specified using precision points.

scholarly journals Displacement mechanical amplifiers designed on poly-silicon

2019 ◽  
Vol 9 (2) ◽  
pp. 894
Author(s):  
Ramon Cabello-Ruiz ◽  
Margarita Tecpoyotl-Torres ◽  
Alfonso Torres-Jacome ◽  
Gerardo Vera-Dimas ◽  
Svetlana Koshevaya ◽  
...  
Keyword(s):  
Compliant Mechanisms ◽  
Capacitive Accelerometer ◽  
Poly Silicon ◽  
Displacement Sensitivity ◽  
Plane Mode ◽  
Operation Frequency ◽  
Ansys Workbench

Using Poly-Silicon, the implementation of novel Displacement-amplifying Compliant Mechanisms (DaCM), in two geometries of accelerometers, allows for remarkable improvements in their operation frequency and displacement sensitivity, with different proportions. Similar DaCM´s geometries were previously implemented by us with Silicon. In all mentioned cases, the geometries of DaCM´s are adjusted in order to use them with Conventional Capacitive Accelerometer (CCA) and Capacitive Accelerometer with Extended Beams (CAEB), which operate in-plane mode, (y-axis). It should be noted that CAEB shows improvements (95.33%) in displacement sensitivity compared to ACC. Simulations results, carried out using Ansys Workbench software, validate the system’s performance designed with Poly-Silicon. Finally, a comparison with the similar systems, previously designed with Silicon, is also carried out.

Design and Development of Flexible Systems Load Deflection Tester

2019 ◽  
Author(s):  
Ayse Tekes ◽  
Mohammed Mayeed ◽  
Kevin McFall
Keyword(s):  
Compliant Mechanisms ◽  
Low Cost ◽  
Force Sensor ◽  
Flexible Systems ◽  
Deflection Curve ◽  
Design And Development ◽  
Vision Measurement ◽  
Stepper Motors ◽  
3D Printed ◽  
Deflection Test

Abstract This study presents the design and development of a novel, low-cost load-deflection test setup providing the testing of flexible links and compliant mechanisms. Test bench consists of two stepper motors, lead screw, rail system, two carts, two clamps, bearings and a force sensor. Clamps are designed in a way to attach various types of compliant members such as pinned-pinned buckling beam, fixed-fixed beam and 3D printed links. Mechanism enables to calculate the stiffness of compliant and 3D printed flexible systems. Sliders are displaced quasi-statically to slowly stretch or compress the flexible members attached in between two clamps. Displacement of the carts and deflection of the midpoint of the buckling beams are captured using machine vision measurement. Force applied from one of the carts to the end of the attached link is recorded using the force sensor. Stiffness of 3D printed flexible translational vibratory mechanisms is obtained using the displacement of the carts and load deflection curve of buckling beams are obtained using deflection curve and load data. Experimental results are compared with the same simulations performed by FEA analysis.

scholarly journals Structural Optimization Using the Simultaneous Perturbation Stochastic Approximation Algorithm

2009 ◽  
Vol 3 (3) ◽  
pp. 407-424
Author(s):  
D. Hamidian ◽  
S.M. Seyedpoor
Keyword(s):  
Structural Optimization ◽  
Stochastic Approximation ◽  
Optimization Problem ◽  
Computational Cost ◽  
Optimization Methods ◽  
Global Optimum ◽  
Size Optimization ◽  
Simultaneous Perturbation Stochastic Approximation ◽  
Stochastic Nature ◽  
Problem Dimension

This paper presents an application of the simultaneous perturbation stochastic approximation (SPSA) method to size optimization of structures. This method can predict a gradient approximation that needs only two measurements of the objective function regardless of optimization problem dimension. This characteristic is very promising in reducing the computational cost of optimization process, especially in problems with a large number of variables to be optimized. Furthermore, the stochastic nature of SPSA can enhance the convergence of the method to achieve the global optimum. Some test examples are considered to demonstrate the effectiveness of the method when compared with the other optimization methods found in the literature. Numerical results reveal the computational merits of the SPSA-based method for structural optimization.

Freeform Skeletal Shape Optimization of Compliant Mechanisms

2003 ◽  
Vol 125 (2) ◽  
pp. 253-261 ◽  
Author(s):  
Dong Xu ◽  
G. K. Ananthasuresh
Keyword(s):  
Shape Optimization ◽  
Compliant Mechanisms ◽  
Optimization Methods ◽  
Optimization Method ◽  
Analytical Sensitivity ◽  
Adaptive Finite Element ◽  
Bezier Curves ◽  
Bézier Curves ◽  
Element Discretization ◽  
Analytical Sensitivity Analysis

Compliant mechanisms are elastic continua used to transmit or transform force and motion mechanically. The topology optimization methods developed for compliant mechanisms also give the shape for a chosen parameterization of the design domain with a fixed mesh. However, in these methods, the shapes of the flexible segments in the resulting optimal solutions are restricted either by the type or the resolution of the design parameterization. This limitation is overcome in this paper by focusing on optimizing the skeletal shape of the compliant segments in a given topology. It is accomplished by identifying such segments in the topology and representing them using Bezier curves. The vertices of the Bezier control polygon are used to parameterize the shape-design space. Uniform parameter steps of the Bezier curves naturally enable adaptive finite element discretization of the segments as their shapes change. Practical constraints such as avoiding intersections with other segments, self-intersections, and restrictions on the available space and material, are incorporated into the formulation. A multi-criteria function from our prior work is used as the objective. Analytical sensitivity analysis for the objective and constraints is presented and is used in the numerical optimization. Examples are included to illustrate the shape optimization method.

Topology and Size–Shape Optimization of an Adaptive Compliant Gripper with High Mechanical Advantage for Grasping Irregular Objects

Robotica ◽  
2019 ◽  
Vol 37 (08) ◽  
pp. 1383-1400 ◽  
Author(s):  
Chih-Hsing Liu ◽  
Chen-Hua Chiu ◽  
Mao-Cheng Hsu ◽  
Yang Chen ◽  
Yen-Pin Chiang
Keyword(s):  
Topology Optimization ◽  
Optimal Design ◽  
Shape Optimization ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Experimental Studies ◽  
Design Procedure ◽  
Optimization Methods ◽  
Optimization Method ◽  
Mechanical Advantage

SummaryThis study presents an optimal design procedure including topology optimization and size–shape optimization methods to maximize mechanical advantage (which is defined as the ratio of output force to input force) of the synthesized compliant mechanism. The formulation of the topology optimization method to design compliant mechanisms with multiple output ports is presented. The topology-optimized result is used as the initial design domain for subsequent size–shape optimization process. The proposed optimal design procedure is used to synthesize an adaptive compliant gripper with high mechanical advantage. The proposed gripper is a monolithic two-finger design and is prototyped using silicon rubber. Experimental studies including mechanical advantage test, object grasping test, and payload test are carried out to evaluate the design. The results show that the proposed adaptive complaint gripper assembly can effectively grasp irregular objects up to 2.7 kg.

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