Compliant Elements Research Articles

Understanding the GDPR from a requirements engineering perspective—a systematic mapping study on regulatory data protection requirements

AbstractData protection compliance is critical from a requirements engineering (RE) perspective, both from a software development lifecycle (SDLC) perspective and regulatory compliance. Not including these requirements from the early phases of the SDLC can prove costly and challenging afterward. The general data protection regulation (GDPR) from the European Union (EU) sets a list of requirements that organizations working within its scope should satisfy. However, these requirements are complex to work with, as legal prose tends to be vague and imprecise, and not all requirements have received the same attention from researchers. This study aims to identify the research published in RE for helping compliance with regulatory data protection requirements. We gathered and analyzed 90 articles from 2016 to 2022 through a systematic mapping study. We analyzed key trends in the sample, such as year of publication, publication venue, type of research, interdisciplinarity in the author’s background, GDPR focus of compliance element, and type of proposal. Our main findings show ongoing interest, mostly published in conferences, in achieving overall compliance with the GDPR and consent as the most popular topics. Other topics, such as cookies or children’s data, did not receive significant attention. Research over the whole RE process has been done. 20 (22%) of the papers have authors affiliated with non-computer science; however, most research seems not interdisciplinary. We finally discuss gaps in the literature, possible future areas of research, and the importance of interdisciplinary research for regulatory data protection requirements in RE.

Modeling of compliant-based support for large aperture rotary prisms with horizontal-axis

In the Thirty-Meter-Telescope (TMT), a pair of wedge prisms with diameters of approximately 1500 mm are proposed to mitigate atmospheric dispersion across different zenith angles. This is achieved through controlled linear and rotary movements of the prisms. However, providing stable support for such large aperture prisms, with variable cross-sections and capable of rotating 360° around a horizontal optical axis, poses a significant challenge. This paper introduces a compliant-based support method tailored for TMT’s large aperture prisms. The methodology involves a mechanical analysis of the wedge prism with push-pull forces combination, followed by the development of the support principle based on degrees of freedom and constraints analysis. Subsequently, numerical modeling is conducted using compliant elements as the fundamental units. Furthermore, an integrated optomechanical analysis is performed to evaluate the performance of the support. The findings demonstrate that employing this support method results in superior optical surface accuracy under the coupled conditions of gravity and temperature, particularly for prisms with large apertures, variable cross-sections, and rotational capabilities.

Navigating compliance and regulations in marketing analytics: Upholding ethical standards and consumer trust

This paper delves into the multifaceted marketing analytics compliance and regulation landscape across diverse business sectors and legal frameworks. It discusses a spectrum of norms with respect to overseeing data collection, processing and utilisation in marketing endeavours. Stringent global laws govern the handling of personal data, necessitating strict adherence. The paper scrutinises pivotal compliance elements like consent, transparency and data security alongside pivotal legislation like the California Consumer Privacy Act and the General Data Protection Regulation. It assesses the implications for marketing analytics, emphasising rights regarding personal data access, erasure anonymisation methods and ethical data use. Non-compliance repercussions, encompassing legal and financial risks and reputational harm, are highlighted, as many industries are facing distinct regulatory challenges. The paper details the essential components of policies, training, monitoring and enforcement that are crucial to ensuring marketing compliance. It stresses the role of technology, advocating for marketing compliance software to streamline processes, monitor compliance and adapt swiftly to regulatory shifts. It elucidates the collaborative nature needed within marketing teams to achieve effective compliance management. The conclusion highlights how compliance software helps with regulatory updates, data privacy, monitoring and content assessment. This paper emphasises the dynamic nature of marketing analytics compliance, urging vigilance with regard to legislative alterations and technological advancements. The paper provides a comprehensive insight into managing compliance challenges in this evolving field while upholding ethical standards and fostering consumer trust.

Effects of Pressure Rollers with Variable Compliance in the Microfinishing Process Utilizing Abrasive Films.

This article presents a comprehensive investigation into pressure rollers utilized in the microfinishing process, covering aspects such as design, experimental properties, compliance, and finite element simulation. Prototype pressure rollers with unconventional elastomer configurations were designed and analyzed to explore their effectiveness in achieving superior surface finishes. Experimental analysis and finite element simulations were conducted to gain insights into the performance and behavior of these pressure rollers under various loading conditions. This study addresses the validation of constitutive material models used in finite element simulations to ensure accuracy and reliability. The results indicate that the applied material model, validated through experimental analysis, accurately predicts pressure roller behavior. Finite element simulations reveal distinct contact zone patterns and stress distributions across the contact surfaces, highlighting the importance of considering deflection-induced variations in contact behavior. Additionally, the investigation evaluates the effectiveness of different pressure rollers in removing surface irregularities during the microfinishing process. Roller R3 demonstrates the highest efficacy in removing surface peaks, suggesting its potential for achieving superior surface finishes. Overall, this research contributes to the advancement of microfinishing techniques by providing insights into pressure roller design, performance, and behavior, thereby optimizing microfinishing processes to produce high-quality components. The urgency of this study arises from the growing need for exceptional surface finishes in various industrial sectors. With manufacturing industries increasingly pursuing high-precision components boasting flawless surface quality, the significance of microfinishing processes is highlighted.

Enhancing and Decoding the Performance of Muscle Actuators with Flexures

Leveraging living muscle as an efficient and adaptive actuator for soft robots has been of increasing interest over the past decade, with a focus on proof‐of‐concept demonstrations of function. Reproducible design and scalable manufacturing of biohybrid machines requires methods to increase the stroke output of strain‐limited muscle actuators and enable accurate and precise quality control and performance monitoring. Compliant mechanical elements, termed flexures, are designed to enhance muscle contractile stroke to ≈5× previously reported values and decode contraction dynamics with high spatiotemporal resolution. Combining rigid and flexible elements within a linear elastic flexure enables us to outperform the sensitivity of gold standard elastomeric beam‐based measurements of muscle contraction at both low‐ and high‐frequency stimulations. Flexures are leveraged to make quantitative comparisons of force, work, and power outputs in muscle actuators, driving us to discover a new observation of frequency‐dependent fatigue in muscle, and also develop a novel method for tuning muscle contractile dynamics in a frequency‐independent manner. By enhancing the contractile stroke of muscle actuators and precisely tuning contractile dynamics and endurance with unprecedented precision, this study sets the stage for leveraging flexures to improve robust, reproducible, and predictive design and manufacturing of next‐generation biohybrid robots.

Data-driven control of a five-bar parallel robot with compliant joints

This paper presents a data-driven control approach for a five-bar robot with compliant joints. The robot consists of a parallel mechanism with compliant elements that introduce uncertainties in modeling and control. To address this fact, it is implemented a model-less data-driven controller based on a Feedforward Neural Network Module (FNNM) that identifies the inverse dynamics of the robot. The FNNM is incorporated into a coordination of Feedforward Control Method (CFCM) to achieve precise trajectory tracking. Experiments compare the compliant joints robot to a bearing-joint robot performing pick-and-place tasks from 0.15 to 3.15 Hz. Results show the compliant robot maintaining trajectory tracking up to 1.25 Hz with a Root Mean Square Error (RMSE) of 9.02 mm.

Role of compliant mechanics and motor control in hopping - from human to robot

Compliant leg function found during bouncy gaits in humans and animals can be considered a role model for designing and controlling bioinspired robots and assistive devices. The human musculoskeletal design and control differ from distal to proximal joints in the leg. The specific mechanical properties of different leg parts could simplify motor control, e.g., by taking advantage of passive body dynamics. This control embodiment is complemented by neural reflex circuitries shaping human motor control. This study investigates the contribution of specific passive and active properties at different leg joint levels in human hopping at different hopping frequencies. We analyze the kinematics and kinetics of human leg joints to design and control a bioinspired hopping robot. In addition, this robot is used as a test rig to validate the identified concepts from human hopping. We found that the more distal the joint, the higher the possibility of benefit from passive compliant leg structures. A passive elastic element nicely describes the ankle joint function. In contrast, a more significant contribution to energy management using an active element (e.g., by feedback control) is predicted for the knee and hip joints. The ankle and knee joints are the key contributors to adjusting hopping frequency. Humans can speed up hopping by increasing ankle stiffness and tuning corresponding knee control parameters. We found that the force-modulated compliance (FMC) as an abstract reflex-based control beside a fixed spring can predict human knee torque-angle patterns at different frequencies. These developed bioinspired models for ankle and knee joints were applied to design and control the EPA-hopper-II robot. The experimental results support our biomechanical findings while indicating potential robot improvements. Based on the proposed model and the robot’s experimental results, passive compliant elements (e.g. tendons) have a larger capacity to contribute to the distal joint function compared to proximal joints. With the use of more compliant elements in the distal joint, a larger contribution to managing energy changes is observed in the upper joints.

The Claw: An Avian-Inspired, Large Scale, Hybrid Rigid-Continuum Gripper

Most robotic hands have been created at roughly the scale of the human hand, with rigid components forming the core structural elements of the fingers. This focus on the human hand has concentrated attention on operations within the human hand scale, and on the handling of objects suitable for grasping with current robot hands. In this paper, we describe the design, development, and testing of a four-fingered gripper which features a novel combination of actively actuated rigid and compliant elements. The scale of the gripper is unusually large compared to most existing robot hands. The overall goal for the hand is to explore compliant grasping of potentially fragile objects of a size not typically considered. The arrangement of the digits is inspired by the feet of birds, specifically raptors. We detail the motivation for this physical hand structure, its design and operation, and describe testing conducted to assess its capabilities. The results demonstrate the effectiveness of the hand in grasping delicate objects of relatively large size and highlight some limitations of the underlying rigid/compliant hybrid design.

Leveraging pleat folds and soft compliant elements in inflatable fabric beams.

Inflatable fabric beams (IFBs) integrating pleat folds can generate complex motion by modifying the pleat characteristics (e.g., dimensions, orientations). However, the capability of the IFB to return to the folded configuration relies upon the elasticity of the fabrics, requiring additional pressure inputs or complementary mechanisms. Using soft compliant elements (SCEs) assembled onto pleat folds is an appealing approach to improving the IFB elasticity and providing a range of spatial configurations when pressurized. This study introduces an actuator comprising an IFB with pleat folds and SCEs. By methodologically assembling the SCEs onto the pleat folds, we constrain the IFB unfolding to achieve out-of-plane motion at 5 kPa. Besides, the proposed actuator can generate angular displacement by regulating the input pressure ( 5 kPa). A matrix-based representation and model are proposed to analyze the actuator motion. We experimentally study the actuator's angular displacement by modifying SCE shapes, fold dimensions, and assembly distances of SCEs. Moreover, we analyze the effects of incorporating two SCEs onto a pleat fold. Our results show that the actuator motion can be tuned by integrating SCEs with different stiffness and varying the pleat fold dimensions. In addition, we demonstrate that the integration of two SCEs onto the pleat fold permits the actuator to return to its folded configuration when depressurized. In order to demonstrate the versatility of the proposed actuator, we devise and conduct experiments showcasing the implementation of a planar serial manipulator and a soft gripper with two grasping modalities.

Minimizing torque requirements in robotic manipulation through elastic elements optimization in a physics engine

The increasing number of robots and the rising cost of electricity have spurred research into energy-reducing concepts in robotics. One such concept, elastic actuation, introduces compliant elements such as springs into the robot structure. This article presents a comparative analysis between two types of elastic actuation, namely, monoarticular parallel elastic actuation and biarticular parallel elastic actuation, and demonstrates an end-to-end pipeline for their optimization. Starting from the real-world system identification of an RRR robotic arm, we calibrate a simulation model in a general-purpose physics engine and employ in silico evolutionary optimization to co-optimize spring configurations and trajectories for a pick-and-place task. Finally, we successfully transfer the in silico optimized elastic elements and trajectory to the real-world prototype. Our results substantiate the ability of elastic actuation to reduce the actuators’ torque requirements heavily. In contrast to previous work, we highlight the superior performance of the biarticular variant over the monoarticular configuration. Furthermore, we show that a combination of both proves most effective. This work provides valuable insights into the torque-reducing use of elastic actuation and demonstrates an actuator-invariant in silico optimization methodology capable of bridging the sim2real gap.

Impact of Added Passive Compliance On the Performance of Tip-Actuated Flexible Manipulators

Abstract With their inherent compliance, flexible manipulator systems (FMSs) are increasingly finding new applications, such as robotic surgeries requiring safe interaction with the environment. While force-controlled FMSs are desirable, an added passive, compliant element can enhance safety while preserving performance. This paper explores the effects of added compliance on tip-actuated FMSs. A detailed analysis compares the impacts of additional compliance, and comparisons are made with a baseline no-compliance case. It is observed that the series compliance provides added safety but with some compromise on performance and stability. In contrast, parallel compliance improves stability and performance without compromising safety in interaction. While similar insights have been well-understood in the context of rigid-link robots, it is interesting to observe that additional series compliance in tip-actuated flexible manipulators is undesirable, unlike for rigid-link robots.

Hybrid gray and black-box nonlinear system identification of an elastomer joint flexible robotic manipulator

Series elastic actuators possess several properties that make them widely used in collaborative robots, which play a major role in the current paradigm of industry 4.0. However, the compliant element responsible for those desired properties can also be responsible for the addition of unmodeled nonlinearities in the system. Therefore, the aim of this paper is to propose a novel hybrid model approach and apply it in the modeling of an elastomer-based series elastic joint. The proposed hybrid model combines a phenomenological gray-box model with a black-box Nonlinear Auto-regressive model with Exogenous inputs, which is able to provide the desired physical insight while enhancing accuracy by addressing the unknown nonlinearities. The results showed that the proposed hybrid model is more than 60% more accurate than the phenomenological model, considering the mean square error, and obtained a multiple correlation coefficient up to 0.97, indicating its capacity to be used in the construction of a digital twin of the system.

Compliant Joints Utilizing the Principle of Closed Form Pressure Balancing

Abstract Compliant joints have significant advantages compared to rigid-body hinges due to a monolithic design and the absence of friction, which prevents effects like wear, backlash, and stick-slip behavior. However, the loading capability is often limited and the support stiffness generally decreases during rotation. A new design principle called closed form pressure balancing has been proposed as a solution to improve these limitations. By using an incompressible fluid as the main compliant element, the support stiffness becomes independent of rotation and buckling no longer limits the loading capability. This work analyzes the fundamental working principle behind closed form pressure balancing and introduces a 2D design model to determine stiffness properties. The design model is validated with a finite element model and used to construct an optimization strategy for optimum joint performance. Additionally, a conversion model and some practical considerations are presented for the transition to a 3D design model.

An online learning algorithm for adapting leg stiffness and stride angle for efficient quadruped robot trotting.

Animals adjust their leg stiffness and stride angle in response to changing ground conditions and gait parameters, resulting in improved stability and reduced energy consumption. This paper presents an online learning algorithm that attempts to mimic such animal behavior by maximizing energy efficiency on the fly or equivalently, minimizing the cost of transport of legged robots by adaptively changing the leg stiffness and stride angle while the robot is traversing on grounds with unknown characteristics. The algorithm employs an approximate stochastic gradient method to change the parameters in real-time, and has the following advantages: (1) the algorithm is computationally efficient and suitable for real-time operation; (2) it does not require training; (3) it is model-free, implying that precise modeling of the robot is not required for good performance; and (4) the algorithm is generally applicable and can be easily incorporated into a variety of legged robots with adaptable parameters and gaits beyond those implemented in this paper. Results of exhaustive performance assessment through numerical simulations and experiments on an under-actuated quadruped robot with compliant legs are included in the paper. The robot platform used a pneumatic piston in each leg as a variable, passive compliant element. Performance evaluation using simulations and experiments indicated that the algorithm was capable of converging to near-optimal values of the cost of transport for given operating conditions, terrain properties, and gait characteristics with no prior knowledge of the terrain and gait conditions. The simplicity of the algorithm and its demonstrably improved performance make the approach of this paper an excellent candidate for adaptively controlling tunable parameters of compliant, legged robots.

Design and analysis of a piezo-actuated 2-DOF high-precision parallel pointing mechanism capable of carrying a heavy load

This paper presents the design, modeling, analysis, and test of a 2-degree-of-freedom (2-DOF) high-precision parallel pointing mechanism capable of carrying a heavy load up to 30 N⋅m driven by high voltage piezo-stack actuators (HVPSAs). The proposed pointing mechanism, which employs flexure hinges as joints, provides two tilting degrees of freedom and can be utilized for intersatellite optical communication, remote sensing satellite lens pointing, and other engineering fields requiring large load capability. In this paper different kinds of flexure hinges are utilized to achieve the desired motion and working performance. With consideration of most compliant elements, Castigliano’s second theorem was adopted to establish the analytical static model of the mechanism, which was then validated by FEA simulation and experimental testing. Finally, a high-precision pointing prototype is fabricated and a series of motion performance tests have been implemented, which validated the feasibility of the proposed system. The superiority of the proposed design is that it possesses large load capacity as well as excellent pointing performance simultaneously, while the former characteristic was infrequently reported in previous works.

Directionally Compliant Legs Enabling Crevasse Traversal in Small Ground‐Based Robots

Small ground‐based robots show promise for locomotion on complex surfaces. A critical application area for such robots is movement over complex terrain and within constricted space such as narrow gaps in rubble. To contend with this terrain complexity, robots typically require high degree‐of‐freedom (DOF) limbs. However, for small robot platforms, this approach of high DOF legs is impractical due to actuator limitations. This presents an opportunity to design robots whose morphology enables the outsourcing of computational tasks to the robot body through the use of compliant elements (morphological computation). Herein, a novel robot appendage is developed that can passively compress in a programmed direction in response to environmental constrictions. A robot equipped with these appendages can enter narrow spaces down to 72% of the robot's sprawled body width as well as low ceilings down to 68% its freestanding height. The robot is able to step onto and over small terrain features ( hip height) and navigate various natural terrain types with ease. The results show that these compressible appendages enable versatile robot locomotion for robot exploration in previously unmapped environments.

Design of compliant mechanisms based on compliant building elements. Part I: Principles

In this paper, we present a new design method and principle, i.e., Compliant Building Elements (CBE), for compliant mechanisms that adopts a systematic and synthetic approach to generate practicable flexure designs. The CBE is unique in that it encodes a compliant system's quantitative information, including elasticity, geometry, location, and orientation, in a parametric matrix. Based on the matrix, a degree-of-freedom (DOF) concept is defined to describe permitted motions of a flexure; next, the screw theory is used to guide the design and synthesis of compliant mechanisms from DOF decomposition to actuator layout selection. In CBE, a compliant system consists of three types of compliant elements, i.e., compliant elements formed by serial or parallel connections and basic compliant elements. The synthesis procedure is a top-down and iterative process, starting from laying out the stage topology to finally optimizing the compliant connection elements and types (i.e., serial or parallel), where the iteration stops when the stage characteristics meet the design requirements. A library of various compliant elements is provided to help the designers quickly generate the initial stage topological designs and optimize the performance with reduced design iterations. The matrix-based design method for compliant mechanisms, i.e., CBE, which is analogous to the screw-based type synthesis for rigid parallel mechanisms, enables early-stage flexure system design via building compliant blocks just like building LEGO® bricks.

Design of compliant mechanisms based on compliant building elements. Part II: Practice

In Part II, we present the use and application of the Compliant Building Elements (CBE) method to generate practical designs for different multiple degree-of-freedom (DOF) compliant mechanisms. We first create a compliant mechanism library based on the combination of prismatic beams, which includes commonly used basic elements (BEs), serial elements (SEs), and parallel elements (PEs). Examples are given during the construction of the library. Based on the library and CBE method, we demonstrate the design of a six-axis nanopositioner, a compliant steering mechanism, and a one-dimensional mechanical metamaterial structure. The outcome of each design process yields a flexure topology that meets the design requirements as well as the corresponding parametric stiffness and compliance matrices, from which we can efficiently obtain the kinematic characteristics of the flexure system and optimize the stiffnesses in selected axes.

Dynamic photoelastic study of flexure hinges produced by additive manufacturing technology

There are many challenges in compliant mechanism redesign for additive manufacturing (AM) technologies, and in order to assess their applicability and propose adequate recommendations, the behavior of compliant elements has to be examined. Plastic materials are often used in AM technologies and are well suited for large volume compliant mechanisms due to their flexibility to strength ratio. However, they also have many disadvantages, notably a low fatigue strength and complex material behavior. Therefore, in this paper a photoelastic observations of corner-filleted flexure hinges manufactured from the transparent acrylic based photopolymer using the Digital Light Processing (DLP) AM technology subjected to the dynamic loading have been conducted in order to assess the fatigue strength and potentials of the photoelastic methods for the material behavior modeling. Three-point flexural tests on rectangular beam samples with the standardized dimensions printed in vertical and in horizontal orientation have been performed and the obtained data has been used for numerical simulations of corner-filleted flexure hinges. The specimens printed in different orientations exhibit significantly different anisotropic properties; the horizontally printed samples exhibit brittle behavior, while the samples printed vertically yields and consequently have much higher deformations, the calculated flexural moduli are also very different. Corner-filleted flexure hinges printed in vertical orientation and subjected to dynamic cantilever beam bending tests at relatively high stress amplitudes proved sufficient for the low dynamic compliant mechanisms applications. The qualitative photoelastic observations have shown that the photoelasticity is applicable in dynamic tests and useful in residual stress determination and stress concentration investigations.

The impact of corruption on the performance of Islamic banking in the United Arab Emirates: empirical evidence by using static panel analysis

Purpose- The major objective of this paper was to scrutinize the impact of corruption control on Islamic banking performance in the United Arab Emirates. So the performance of Islamic banks was determined by the profitability as a specific objective of this study. Methodology- Panel data was grounded on quantitative analysis applied. Also, the study collects data from secondary sources from 2000 up to 2019. The sample of this paper comprised a total of 18 banks that were selected in the UAE. Data were collected from the World Bank data set and annual financial reports for each selected bank. The study analyzed the data based on descriptive statistic, correlation matrix, and static models which includes pooled OLS model, random effect, and fixed effect to achieve the study objective. So, results were presented in the form of tables for descriptive analyses of the key variables applied, correlation as well as static models. The static model that was applied for this study provides the uniqueness of this paper because most of the previous corresponding studies did not employ a static model but used a dynamic model especially the Generalized Method of moment (GMM). So, the originality of this study firstly, it is the earliest study that used a static model, and secondly, this study may be the first to look at the impact of corruption control on Islamic bank's profitability. This is because most of the study is based on the impact of corruption and not corruption control like this study. Findings – The findings have shown that corruption control and bank profitability have a statistical correlation relationship and its coefficient revealed a positive association which indicates that in the UAE control of corruption would increase the profitability of Islamic banks. The discussions of the findings show that some previous studies are consistence with the study while others are inconsistent. The results of this implied that the Islamic bank flourish and benefit from the corruption-controlling strategies that existed in UAE. Conclusion – The study recommends that in UAE and other countries the zero-tolerance policy for corruption mitigation and eradication is a perfect way, efforts should take and should be achievable right now. So alternative way to expression at this is in terms of Islamic finance should not tolerate non-Shariah compliant elements and any element of the practice of corruption. So, the strong practice of corruption in the Muslim states and non-Muslim states hinders the progress of Islamic financial institutions (IFIs). From these results, Islamic finance should insist on the application of its principles for every Industry that offers Islamic finance products and services.