Compliant Design Research Articles

On the Design of a Simulation-Assisted Human-Centered Quasi-Stiffness-Based Actuator for Ankle Orthosis

Most exoskeletons designed to assist users in load-bearing tasks face a mechanical dilemma in their conception. Designers may find a compromise between stiff active actuators-based architectures which are powerful but bulky and compliant actuator-based designs which are much less assistive but less constraining for users. This article presents a new open-source simulation-based design tool and a human-centered method that lets orthosis designers explore different device configurations and evaluate some performance criteria. This framework was applied in three different young-adult subjects. The effects of design personalization on user morphology and gait were studied. First, an ankle–foot orthosis designed to support a 20 kg backpack was defined according to the user’s height, weight, and walking speed. Then, a simulation of the subjects fitted with their customized design walking at a self-selected speed on flat ground carrying this additional load was performed. First, the results showed that the designed method inspired by natural joint stiffness behavior provided viable personalized mechanisms. Second, significant reductions in peak joint torque and mean joint activity were observed when comparing muscle-generated torques while the subject was wearing the 20 kg backpack with ankle–foot orthoses on both legs or without. Finally, it shows the value of an open-access tool for exploring the coupling of passive and active actuators to generate lighter and more compliant designs.

Distributed Electric Propulsion and Flight Control Concept to Meet EASA SC-VTOL-01 10‐9 Catastrophic Failure Criteria

The objective of the current work was to develop an all-electric distributed propulsion and flight control (DPFC) architecture that will have no more than 10‐9 catastrophic failures per flight hour (pfh). The DPFC architecture was broken into four system design teams: (i) electrical power and distribution system, (ii) drive and power system, (iii) thermal management system, and (iv) flight control system. System designs were updated and iterated upon, working with reliability and safety analysis teams to develop compliant designs. The firm designs were reflected in a preliminary system safety assessment (PSSA) for initial verification of compliance. Additionally, design and analysis excursions are presented in which aircraft attributes were modified to investigate sensitivities to propulsion type, number of rotors, and control schemes. Excursion results found that all aircraft evaluated likely have paths to comply with the stringent, probabilistic catastrophic failure criteria. However, stability and control models showed large power transients that must be addressed, and PSSA results show that future work is needed in single load path structures, high voltage power storage and distribution, and motor/rotor overspeed protection.

Materialising structural optimisation of reinforced concrete beams through digital fabrication

This study tackles the design, fabrication and testing of truss-like reinforced concrete beams. The paper introduces the strut optimisation method, a Eurocode 2-compliant design procedure which allows to optimise the shear strength of beams. The procedure is embedded in a numerical workflow that automates the design and fabrication of beams. Through a parametric study, potential concrete savings of 24% to 64% are estimated. A digital manufacturing workflow is presented. It is based on the 3D printing of recyclable clay moulds allowing to cast the hollowed-out parts truss-like elements. The fabrication of a 3 m-long prototype illustrates the implementation of the process. Four-point bending tests made on SOM-optimised specimens validate the compliance between the empirical behaviour and the theoretical model, paving the way for wider adoption of materially-efficient reinforced concrete beams.

Soft-stable interface in grasping multiple objects by wiring-tension

Efficiently manipulating objects in a group state poses an emerging challenge for soft robot hands. Overcoming this problem necessitates the development of hands with highly stable structures to bear heavy loads and highly compliant designs to universally adapt to various object geometries. This study introduces a novel platform for the development of robot hands aimed at manipulating multiple objects in each trial. In this setup, the objects come into soft contact with an elastic wire affixed to the finger skeletons. This combination results in a harmonious hybrid finger, inheriting both the soft, flexible properties of the wire and the robust stability provided by the finger skeleton. To facilitate this approach, a theoretical model was proposed to estimate the kinematics of manipulating multiple objects using wiring-based fingers. Based on this model, we designed a hybrid gripper comprising two wiring-based fingers for conducting experimental evaluations in manipulating four groups of samples: a pair of bevel gears, a pair of bevel gears plus a pneumatic connector, a pair of glue bottles, and a pair of silicon bottles. The experimental results demonstrated that our proposed gripper reached good performance with high success rates in durability tests conducted at various lifting velocities and high adaption with objects in soft-friendly ways. These findings hold promise for efficiently manipulating multiple complex objects in each trial without the need for complex control systems.

Development of compliant modular floating photovoltaic farm for coastal conditions

Floating photovoltaic (PV) farms can be constructed in coastal marine conditions for the abundant ocean space compared to reservoirs. New challenges may arise when extending existing designs of reservoir floating PV farms to coastal regions because of the complex environmental conditions, especially for the pontoon type floating PV systems. This study presents the methodologies for the design and verification of such floating PV farms based on the practical example of one of the world's largest nearshore floating photovoltaic farms off Woodlands in Singapore. This 5 MW pilot project aims to move floating PV farms from inland water to nearshore regions for future larger-scale deployments. The innovative floating system is adapted from the successful modular floating PV development at Tengeh Reservoir and improved to withstand harsher marine environmental conditions. This study comprehensively introduces various aspects of the development of the nearshore floating modular PV farm, including its design, verification via full-scale experimental testing and numerical studies, construction, and power generation performances. The floating PV system comprises standardized floating modules made of high-density polyethylene (HDPE) that support PV panels or operational and maintenance work. A compliant design allows the floating system to follow wave motion. A verification study was conducted through full-scale experimental tests and numerical simulations based on a representative subsystem of the floating PV farm, focusing on its hydrodynamic performance. Finally, this study presents and discuss the on-site operational energy production performance. This study may serve as a reference for developing large-scale floating PV farms in coastal marine conditions.

Go Beyond Compliance: Use Individualized Education Programs to Answer Strategic Questions and Improve Programs.

The most significant document to ensure effective and compliant design, implementation, monitoring, and enforcement of a program of special education services in the United States is the Individualized Education Program (IEP). Although IEPs have been used to document procedural compliance with the Individuals with Disabilities Education Act (IDEA) for individual students, IEPs also provide extensive data that can and should be used by a variety of stakeholders including speech-language pathologists (SLPs), school administrators, and state education agencies to design targeted professional development and collectively improve programs, processes, and outcomes in special education. We summarize existing literature on the use of IEP data and describe opportunities to use IEP data to analyze individual student service patterns and SLP practice patterns. Aggregated IEP data also provide a robust view of district-wide and state trends in eligibility rates and least restrictive environment settings. Information on current and potential IEP data uses, reflection questions for substantive compliance, and lessons learned from a large-scale analysis of IEP data are provided. These lessons include potential software adjustments to enhance usability as a data source for substantive compliance; program improvement; and monitoring individual, school-wide, and district-wide outcomes. IEP data are a rich data source of information that may be used to (a) identify trends; (b) assist schools, districts, and states with ensuring substantive compliance with IDEA; (c) examine service equity and efficacy; (d) identify professional development needs; and (e) identify promising practices and provide opportunities to use real-time data to improve models and address public policy.

A Machine Learning Based Reliability Analysis of Negative Bias Temperature Instability (NBTI) Compliant Design for Ultra Large Scale Digital Integrated Circuit

NBTI is a key reliability challenge in nanoscale digital design, and it is vital to address it throughout the exploration of design space at high levels of abstraction in order to improve reliability. A prediction model of aging that is adequate for these levels ought to be faster. In addition to this, the model should be able to forecast the recently discovered stochastic consequences of growing older. The purpose of this study is to offer a model that is based on machine learning (ML) and can predict aging effects. After obtaining a training set of sufficient size using Synopsis HSPICE (MOSFET Reliability, MOSRA) in the beginning, the machine-learning-based model is then trained and built in order to forecast the aging statistical features. Evaluation is done on a number of machine learning techniques, including Adaptive Neuro-Fuzzy Inference System (ANFIS), K-Nearest Neighbor (KNN), Support Vector Machine (SVM) and Random Forest (RF). The findings indicate that ANFIS algorithms are very effective in the process of age prediction. The proposed technique shows that the aging prediction runtime is reduced by more than 99% when compared to the MOSRA-based approach, and accurate predictions of the statistical properties of aging are obtained with an accuracy of more than 99% on complementary metal oxide semiconductor (CMOS) and metal gate/high-K (MGK) circuits at the 22nm technology node.

Iterative Learning Control for Compliant Underactuated Arms

Operations involving safe interactions in unstructured environments require robots with adapting behaviors. Compliant manipulators are a promising technology to achieve this goal. Despite that, some classical control problems such as following a trajectory are still open. A typical solution is to compensate the system dynamics with feedback loops. However, this solution increases the effective robot stiffness and jeopardizes the safety property provided by the compliant design. On the other hand, purely feedforward approaches can achieve good tracking performance while preserving the robot intrinsic compliance. However, a feedforward control framework for robots with passive elastic joints is still missing. This article presents an iterative learning control algorithm for purely feedforward trajectory tracking for compliant underactuated arms. Each arm is composed of active elastic joints and a generic number of passive ones connected through rigid links. We prove the convergence of the iterative method, also in the presence of uncertainties and bounded disturbances. Different output functions are analyzed providing conditions, based on the system inertial properties that ensure the algorithm applicability. Additionally, an automatic selection of the learning gain is proposed. Finally, we extensively validate the theoretical results with simulations and experiments.

Improving the Performance of Direct-Conversion SDRs for Radiated Precompliance Measurements

In this letter, a highly linear front end to improve the performance of software-defined radio (SDRs) for radiated precompliance measurements is presented. In CISPR band C/D, the test receiver needs to fulfill stringent requirements for using the quasi-peak detector. Usually, an expensive preselection filter bank is necessary to make fully compliant measurements of broadband transients. Direct-conversion-based SDRs show a limited out-of-the-box performance for precompliance measurements caused by, e.g., harmonic mixing and saturation effects. With the use of a triple-balanced mixer, a highly linear upconversion stage is built, eliminating the need for a filter bank. The dynamic range (DR) requirements for the SDR are strongly reduced by a narrowband intermediate frequency filter, making CISPR 16-1-1 compliant measurements possible. The sensitivity of the front end is comparable to professional receivers on the market, although no low-noise amplifier is implemented. The performance is verified by continuous wave (CW) and transient signals according to CISPR norms. The broadband measurement results are compared with traditional characterizations of the DR using the compression level and the noise figure. It shows that assumptions on the RF-link budget for a compliant design can be made with CW measurements. Based on our results, the requirements for the SDR front end are derived.

Design and seismic evaluation of MRFs in DC2 ductility class introduced in the new prEN1998 draft and comparison with TPMC

This work aims to analyse and evaluate the design rules proposed for DC2 ductility class in the new prEN1998 by means the design and assessment of MRFs with different height and length of the spans. DC2 is a medium ductility class, introduced in the new prEN1998 draft for a more economical design, so simplified design rules are proposed for avoiding only the so-called soft storey mechanism. The purpose of the work is the evaluation of the effectiveness of the proposed rules and the comparison with a more theoretically compliant design rules developed in the framework of the Theory of Plastic Mechanism Control (TPMC) adapted to be used according to the DC2 philosophy. A wide parametric analysis is developed on different structural schemes and the performance evaluation is made through pushover and IDA analyses. It can be pointed out that the soft storey mitigation criteria for the DC2 ductility class is not able to satisfy the design condition. Conversely, the approach based on the TPMC is able to assure the design goal.

A Pattern Language for Inclusive Design: A Set of Patterns for Designing Reusable Accessible Solutions.

A common cause for inconsistent accessibility in the design of ICT applications is that designers work to develop optimal and satisfactory interfaces but they do not take care to comply with all users' needs and possibilities to access. The study presented in this paper stems from a lack of published evidence able to support designs in developing accessible interfaces for websites, mobile apps or conversational Interfaces (chatbot or voicebot). This work aims at investigating accessible design patterns that can be used by designers to implement applications accessible by multiple devices. To solve this problem, we propose a design pattern language able to provide WCAG compliant design out-of-the-box solutions. The navigation through the design patterns allows designers to gather existing solutions based on solid evidence and examples to develop inclusive applications accessible by web, mobile devices or conversational agents.

A structural approach to 3D-printing arterial phantoms with physiologically comparable mechanical characteristics: Preliminary observations.

Pulse wave behavior is important in cardiovascular pathophysiology and arterial phantoms are valuable for studying arterial function. The ability of phantoms to replicate complex arterial elasticity and anatomy is limited by available materials and techniques. The feasibility of improving phantom performance using functional structure designs producible with practical 3D printing technologies was investigated. A novel corrugated wall approach to separate phantom function from material properties was investigated with a series of designs printed from polyester-polyurethane using a low-cost open-source fused filament fabrication 3D printer. Nonpulsatile pressure-diameter data was collected, and a mock circulatory system was used to observe phantom pulse wave behavior and obtain pulse wave velocities. The measured range of nonpulsatile Peterson elastic strain modulus was 5.6–19 to 12.4–33.0 kPa over pressures of 5–35 mmHg for the most to least compliant designs respectively. Pulse wave velocities of 1.5–5 m s−1 over mean pressures of 7–55 mmHg were observed, comparing favorably to reported in vivo pulmonary artery measurements of 1–4 m s−1 across mammals. Phantoms stiffened with increasing pressure in a manner consistent with arteries, and phantom wall elasticity appeared to vary between designs. Using a functional structure approach, practical low-cost 3D-printed production of simple arterial phantoms with mechanical properties that closely match the pulmonary artery is possible. Further functional structure design development to expand the pressure range and physiologic utility of dir"ectly 3D-printed phantoms appears warranted.

BIM-based design decisions documentation using design episodes, explanation tags, and constraints

The process of designing a building involves producing design concepts while fulfilling various requirements and regulations. Furthermore, during the project's life-cycle, multiple experts from multiple domains collaborate in developing the different partial models, including architectural, structural, and HVAC among others. Accordingly, clearly communicating the rationale behind design decisions is crucial for developing regulatory compliant designs that also fit the owner’s needs. The developed designs are the main deliverables exchanged and handed over. However, these deliverables do not include any explanation of design intentions or documentation of design decisions. Communication among parties and reuse of knowledge are hindered by the absent explanation of existing design. To overcome this deficiency, this paper proposes a methodology for digitally documenting design decisions, incorporating their intention and rationale. Architectural concepts and evaluation criteria are represented in the form of explanation tags as well as spatial and semantic constraints, which are assigned to the individual model elements and properties. Additionally, to document how design decisions fulfill owner requirements and regulatory documents, natural language processing (NLP) is employed to facilitate querying those documents and then the individual requirements are linked to specific elements, properties, and constraints. To evaluate the proposed methodology, a prototype was implemented as a plugin inside a BIM- Authoring tool and multiple real-world use cases are discussed.

Demands on acceleration-sensitive nonstructural components in special concentrically braced frame and special moment frame buildings

This study investigates demands on acceleration-sensitive nonstructural components (NSCs) in code-compliant Special Concentrically Braced Frame (SCBF) and Special Moment Frame (SMF) structures. Previous studies have highlighted that the assumption of ASCE 7-16 for the ratio of Peak Floor Acceleration (PFA) to Peak Ground Acceleration (PGA) is overly conservative. In most previous studies, the results were based on generic analytical models with non-deteriorating structural behavior or recorded data from instrumented buildings subjected to ground motions that were significantly weaker than the design-level earthquakes. This study evaluates the acceleration demands on NSCs in 11 archetype buildings modeled using advanced techniques. The ground motions used elicit inelastic response in the frames at the level expected by ASCE 7-16 compliant designs. The study examines the effect of the ratio of NSC period to structural period, NSC damping ratio, and NSC vertical location on these demands. Results of this investigation are compared with the provisions of ASCE 7-16 and the recommendations of the recently completed effort by the Applied Technology Council 120 project (ATC-120), which are the basis for the seismic design requirements for nonstructural components in the forthcoming ASCE 7-22 standard. Equations for the PFA/PGA ratio and NSC amplification factor, which account for the dynamic characteristics of the buildings, are developed based on regression analysis of the generated data. Results of the analyses indicate that the formula recommended by ATC-120 for estimating PFA/PGA along the height of the structure, which includes building nonlinearity effects through a constant building ductility reduction factor, overestimates floor accelerations at the top floors but underestimates them in the lower floors of the archetypes considered. At the same time, results show that the NSC seismic design force equation recommended by ATC-120 is conservative for the SCBF archetypes, while it underestimates the NSC force demands in the SMFs.

Optimal design for disc golf by computational fluid dynamics and machine learning

In this article, we introduce a computational methodology for golf disc shape optimization that employs a novel disc shape parameterization by cubic B-splines. Through application of batch Computational Fluid Dynamics simulations and Machine Learning, the disc parameterization yields functional relationships—so-called shape surrogate models—between the flying rotating disc shape and its flight characteristics. The shape surrogate models facilitate free and constrained optimization in both single- and multiobjective settings, such that both aerodynamic (drag and lift) and structural (mass and moment of inertia) features of the disc are addressed simultaneously. Further, the Professional Disc Golf Association rules for permissible golf discs can be cast as nonlinear constraints for the computational optimization problem. The proposed numerical optimization method yields disc drag coefficient values as low as 0.48 (unconstrained) and 0.52 (constrained) and lift coefficient values as high as 0.26 (unconstrained) and 0.19 (constrained). The presented numerical optimization results also describe the many design tradeoffs between the discs that target long flight range (so-called drivers) and the discs that target flight at low speeds (so-called putters). Moreover, novel optimal rule compliant designs are presented for driver-type and putter-type discs, as well as their compromise, the so-called mid-range discs.

Long-term within- and between-subject biological variation of 29 routine laboratory measurands in athletes.

Within- and between-subject biological variation (BV) estimates have many applications in laboratory medicine. However, robust high-quality BV estimates are lacking for many populations, such as athletes. This study aimed to deliver BV estimates of 29 routine laboratory measurands derived from a Biological Variation Data Critical Appraisal Checklist compliant design in a population of high-endurance athletes. Eleven samples per subject were drawn from 30 triathletes monthly, during a whole sport season. Serum samples were measured in duplicate for proteins, liver enzymes, lipids and kidney-related measurands on an Advia2400 (Siemens Healthineers). After outlier and homogeneity analysis, within-subject (CVI) and between-subject (CVG) biological variation estimates were delivered (CV-ANOVA and log-ANOVA, respectively) and a linear mixed model was applied to analyze the effect of exercise and health related variables. Most CVI estimates were similar or only slightly higher in athletes compared to those reported for the general population, whereas two- to three-fold increases were observed for amylase, ALT, AST and ALP. No effect of exercise and health related variables were observed on the CVI estimates. For seven measurands, data were not homogeneously distributed and BV estimates were therefore not reported. The observation of higher CVI estimates in athletes than what has been reported for the general population may be related to physiological stress over time caused by the continuous practice of exercise. The BV estimates derived from this study could be applied to athlete populations from disciplines in which they exercise under similar conditions of intensity and duration.

Design and evaluation of a dual-stage, compensated stick-slip actuator for long-range, precision compliant mechanisms

Nanomanufacturing and nanoassembly require positioners capable of producing nanometer order precision with millimeter order workspaces. Current nanopositioners are based on compliant mechanisms or stick-slip/inertial drives. Compliant mechanisms give ultra-high precision but small workspaces, while inertial drives are bulky, expensive, and induce large transient errors making them unsuitable for tracking motions. A compliant stick-slip nanopositioner with error compensation was investigated in this research. The compliant design has a range of approximately 960 μm, is simple to manufacture and is suited to miniaturization. A serial error compensation stage was developed using model-predictive control, which is demonstrated to compensate for stick-slip errors and enable linear motion. Compared to the uncompensated design, root mean square tracking errors were reduced by 86% using the model-predictive control strategy. Hence enabling precise, and long-range tracking.

Impact of Roadside Design Compliance and Hazard Offset on the Risk of Single-Vehicle, Run-Off-Road Crash Fatalities

Single-vehicle, run-off-road (SVROR) crashes account for a significant portion of all road-related injuries and fatalities worldwide. However, no previous study has examined to what extent roadside design guidelines have been applied, nor (and most importantly) whether having a compliant roadside design reduces the likelihood of fatal injury occurrence in SVROR crashes. Thus, the objectives of this research are i) to examine the level of roadside design compliance within the studied area based on the selected benchmark and ii) to investigate whether roadside design compliance reduces the likelihood of fatal injury occurrence in SVROR crashes. Findings from this study are based on extensive crash and field data collected from 1,070 SVROR injury collisions and locations, respectively. The study shows that i) only 32 percent of the studied locations contained compliant design, and ii) barrier and discrete-obstacle lateral offsets larger than 6 and 12 meters, respectively, tended to lower fatality risk. The 12-meter clear-zone (CZ) width is larger than that recommended by previous research, which has based CZ width recommendations also on cost-benefit procedures and not just on fatality risk reduction.

Passive shape shifting: A compliant design approach for full film bearings

In tribotronic bearing design active components are used to adapt bearing performance to operating conditions. The principle of self-adaptive bearings has also been presented in literature in which a passive modification of geometry was used for a variation in conditions. This work presents an alternative design approach for self-adaptive bearings. This approach is focused on the shift between two known bearing geometries, where each of them is the preferred solution in a part of the operating regime. Using compliant elements in the bearing design allows for passive shape shifting. Four examples are presented which present this behavior for variable velocity and load conditions. The design approach could possibly provide a cheaper alternative for simple active bearing designs, or could be combined with active components in a tribotronics design to improve existing performance.

Development of system information of building code checking in planning and permitting phase to improve building code compliance based on work breakdown structure (WBS) using building information modeling (BIM)

Purpose: Audit of the requirements for construction project regulations in DKI Jakarta is still conducted conventionally (paper and CAD based) which requires a long time, resource intensive, different interpretations of the regulations, the process of revised repetitive, the process of tracking difficult requirements, inaccurate and not transparent, and has significant time and cost implications. Examination of conventional requirements causes that there are still many buildings in DKI Jakarta that have not yet met the technical requirements requested for building completion and public dissatisfaction. Automatic requirements checking is possible when the computer representation of the product data model (Product Data Model (PDM)) is integrated with the Legal Knowledge Model (LKM) as input for data processing systems or machines with algorithmic procedures as Compliant Design Processes (CDP) to produce an accurate automatic regulatory check report. Methodology: The Building Model developed in Building Information Making (BIM) is made as a building representation. The scope of building technical requirements based on BIM is managed dynamically using Work Breakdown Structure (WBS) in one database that is validated by the Government and can be applied by planners in any planning. This research uses the BIM model and develops a WBS-based Information System with a BIM application. Results: The scope of requirements can be managed by decomposition of work known as Work Breakdown Structure to produce a BIM component that will be subject to regulatory requirements checking. The ability of the BIM can produce building models that can be subject to audit of regulatory requirements. Examination of regulatory requirements can be carried out at each stage of developing the BIM model according to the level of detail of the BIM object. Examination of regulatory requirements can be carried out independently by planners at each stage by using a Web-based Information System developed in the BIM format that has been validated by the Government. Applications/Originality/Value: By grouping requirements based on the stages of development of the BIM model, it will maximize the fulfillment of the requirements at each stage so as to reduce the risk of redesign while at the same time increasing the fulfillment of the technical requirements of the building.