Flexible Joint Research Articles

Study on Anti-Dislocation Performance of a Novel Composite Anti-Dislocation Tunnel Structure Crossing Strike-Slip Faults

ABSTRACT A novel composite anti-dislocation tunnel structure (CATS) is proposed as an anti-dislocation measure for tunnels crossing strike-slip faults. The anti-dislocation performance of CATS is verified through numerical simulation. Parameter analysis is presented for CATS, including the circumferential length of the buffer layer, the buffer layer thickness, segment length, fault dip angle, and fault displacement. The results highlight that CATS can effectively reduce both the peak value and the longitudinal damage distribution range of compressive and tensile damage to the secondary lining. The buffer layer in CATS helps reduce compressive damage to the secondary lining, while the flexible joint in CATS aids in reducing tensile damage to the secondary lining. CATS demonstrates good anti-dislocation performance compared to tunnels without anti-dislocation measures or those with only flexible joints. The buffer layer thickness has little effect on the anti-dislocation performance, while a smaller segment length is more conducive to enhancing the anti-dislocation performance of CATS. The anti-dislocation performance of CATS increases with an increasing fault dip angle; conversely, it decreases as the fault displacement increases. These results can provide valuable references for tunnel anti-dislocation design.

Environmental Economic Scheduling of Microgrid Considering Flexible Loads and Energy Storage Joint Regulation Under Carbon Trading Mechanism

Environmental Economic Scheduling of Microgrid Considering Flexible Loads and Energy Storage Joint Regulation Under Carbon Trading Mechanism

Innovations in Glycosaminoglycan Delivery: Transforming Joint Health Therapies.

This thorough analysis looks critically at how glycosaminoglycan (GAG) supports joint health. It emphasizes the importance of GAG in particular, clarifies the underlying processes linked to joint pain, and assesses the shortcomings of traditional therapy modalities. Additionally, the research delves into several traditional approaches, such as injectable GAG therapy and oral supplements, carefully evaluating the benefits and drawbacks of each. The study then explores novel GAG drug delivery technologies, acknowledging the urgent need for better treatment approaches. The article highlights the potential of hydrogel-based systems, liposomal/micellar carriers, and nanoparticles in addressing current challenges in GAG delivery. These challenges include achieving sustained release, improving bioavailability, facilitating targeted delivery, and reducing safety concerns related to biocompatibility. Examining these elements closely and critically, the review seeks to provide a thorough grasp of the developments, difficulties, and possible breakthroughs in GAG delivery systems. In the end, this thorough investigation will greatly aid in the improvement of joint pain therapies. The results imply that by shielding articular joints from erosive effects, early use of GAG therapy-particularly hyaluronic acid-can reduce joint deterioration associated with arthritis. Even though GAG-based therapies have shown promise in lowering inflammation and increasing joint flexibility, further study is required to improve their effectiveness in treating joint pain, particularly in diseases like osteoarthritis.

Assessment of Joint Behaviour of Immersed Tunnel with Prefabricated Push-Out Closure Joint under Differential Settlement

The deformation behaviour of immersed tunnels with prefabricated push-out closure joint remains unclear. In this study, four model tests were conducted to simulate immersed tunnels subjected to differential settlements. The impact of different settlement crossings on joint behaviours was analyzed. Results indicate that differential settlement directly at the joint position causes significant shear displacement, with decreased perpendicular axial movement. The closure joint shows bidirectional axial movement, while the flexible joint primarily undergoes unidirectional compression. The direction and magnitude of joint rotation depend on the settlement location. Differential settlement at a flexible joint significantly influences the rotation of other joints simultaneously. Premature leakage could occur in adjacent flexible joints when differential settlement occurs at the closure joint. Controlling the axial movement of flexible joint is the most effective approach to manage joint opening and prevent leakage under small differential settlements. A closed-form solution was proposed for estimating the axial movement between closure joint and lining structure. It suggests that the interface shear strength should be greater than 0.25 MPa to limit the maximum axial movement of closure joint within the tolerance. Compared to frictional resistance, more attention should be given to the bonding strength provided by post-construction grouting.

Microwave welding with SiCNW/PMMA nanocomposite thin films: enhanced joint strength and performance

Most previously reported susceptors for microwave welding are in powder form. In this study, a thin-film susceptor was employed due to its uniform heating rate and ease of handling. Silicon carbide nanowhisker (SiCNW) were incorporated into a poly(methyl methacrylate) (PMMA) matrix to create a nanocomposite thin film, which served as the susceptor. The microwave welding process involved three straightforward steps: fabrication of the PMMA/SiCNW nanocomposite thin film, application of the nanocomposite film to the target area, and subsequent microwave heating. Upon cooling, a robust microwave-welded joint was formed. The mechanical properties and microstructure of the welded joints were characterized using single-lap shear tests, three-point bending tests, and scanning electron microscopy. Results demonstrated that the shear strength and elastic modulus of the welded joints were optimized with increased heating time and SiCNW filler loading. This optimization is attributed to the formation of a SiCNW-filled polypropylene (PP) nanocomposite layer of increasing thickness at the welded joint interface. However, the incorporation of SiCNW also constrained the mobility of the PP chains, reducing the joint's flexibility. Furthermore, the welded joint formed with the PMMA/SiCNW nanocomposite thin-film susceptor exhibited an 18.82% improvement in shear strength compared to joints formed with a powdered SiCNW susceptor. This study not only demonstrates the potential of PMMA/SiCNW nanocomposite thin films as efficient susceptors for microwave welding but also paves the way for developing high-performance polymer-based composite joints with improved mechanical properties for applications in the automotive, aerospace, and construction industries.

Research on Composite Strain and Stress Sensors Based on Piezoresistive and Triboelectric Effects

Abstract In view of the problems that robotic arms find it difficult to effectively identify and grasp workpieces with different textures and hardness in complex industrial environments, and the low path planning accuracy of robotic arms in practical application scenarios, this paper proposes a composite sensor based on piezoresistive effect and triboelectric effect. The piezoresistive sensor and the triboelectric sensor simultaneously generate output signals, and the identification of different achieves high-precision dynamic monitoring of the robotic arm's gripping objects and joint movements. The base material of the piezoresistive sensor and the negative electrode material of the triboelectric sensor are both porous MXene/PDMS structures. The piezoresistive sensor enhances its conductivity by spin-coating CNT slurry on the surface of the base material and uses PVA hydrogel as the electrode. The triboelectric sensor uses copper as the positive electrode material. Experiments show that the developed sensor has a measurement range (0.015 kPa-70 kPa) and good repeatability. The experiment verifies that the composite sensor can be applied to the high-precision detection of robotic arm's flexible gripping and joint movements.

Stability and nonlinear dynamics of fluid-conveying pipes connected with flexible joints

Stability and nonlinear dynamics of fluid-conveying pipes connected with flexible joints

Flexible Model Predictive Control for Bounded Gait Generation in Humanoid Robots.

With advancements in bipedal locomotion for humanoid robots, a critical challenge lies in generating gaits that are bounded to ensure stable operation in complex environments. Traditional Model Predictive Control (MPC) methods based on Linear Inverted Pendulum (LIP) or Cart-Table (C-T) methods are straightforward and linear but inadequate for robots with flexible joints and linkages. To overcome this limitation, we propose a Flexible MPC (FMPC) framework that incorporates joint dynamics modeling and emphasizes bounded gait control to enable humanoid robots to achieve stable motion in various conditions. The FMPC is based on an enhanced flexible C-T model as the motion model, featuring an elastic layer and an auxiliary second center of mass (CoM) to simulate joint systems. The flexible C-T model's inversion derivation allows it to be effectively transformed into the predictive equation for the FMPC, therefore enriching its flexible dynamic behavior representation. We further use the Zero Moment Point (ZMP) velocity as a control variable and integrate multiple constraints that emphasize CoM constraint, embed explicit bounded constraint, and integrate ZMP constraint, therefore enabling the control of model flexibility and enhancement of stability. Since all the above constraints are shown to be linear in the control variables, a quadratic programming (QP) problem is established that guarantees that the CoM trajectory is bounded. Lastly, simulations validate the effectiveness of the proposed method, emphasizing its capacity to generate bounded CoM/ZMP trajectories across diverse conditions, underscoring its potential to enhance gait control. In addition, the validation of the simulation of real robot motion on the robots CASBOT and Openloong, in turn, demonstrates the effectiveness and robustness of our approach.

Combining MFAC with an improved cuckoo algorithm for flexible robotic rotary arm joint control

Combining MFAC with an improved cuckoo algorithm for flexible robotic rotary arm joint control

Desain Perancangan Alat Holder Nozzle Pemadam Kebakaran dengan Metode QFD untuk Menurunkan Resiko Kerja

PT ABC is a fuel distribution company operating 24 hours a day, including product receiving and storage activities in tanks across three shifts. A past fire incident at the company highlighted the importance of reliable firefighting equipment. As a solution, a holder nozzle was developed, designed to maintain the nozzle's balance within the firefighting system. This research aims to reduce the ergonomic risks for firefighters and evaluate the effectiveness of the holder nozzle design. The method used involves ergonomic analysis of the nozzle's use during firefighting operations with the cooling technique. The holder nozzle is made of mild steel (Mild Steel/MS), consisting of three main components: a stand hydrant, a pipe stand, and a shaft. Additionally, a flexible joint was added to the discharge pipe to reduce vibration transmission. The results show that the holder nozzle successfully improved firefighting performance by reducing response time, expanding coverage area, and decreasing firefighters' physical fatigue. The implementation of the flexible joint also proved effective in reducing equipment damage risks caused by vibration.

Unified force and motion adaptive-integral control of flexible robot manipulators.

In this paper, we propose an adaptive nonlinear strategy for the motion and force control of manipulators with flexible joints. Our approach provides force control when in contact and robust motion control in its absence, all without the need for a control switch. This self-tuning behaviour for mixed contact/non-contact scenarios results from a unified formulation of force and motion control, with an integral transpose-based inverse kinematics core and adaptive update laws to cope with the manipulator flexibility and the contact stiffnesses. The global boundedness of all signals and the asymptotic stability of this controller are guaranteed via Lyapunov analysis. Finally, we validate its applicability experimentally by using low-cost hardware in a realistic mixed-contact scenario, demonstrating low computational demand.

Enhancing gait mechanics: The effectiveness of a novel walking aid.

A walking support orthosis known as the e-foot®, a rubber orthotic worn from the hip to the forefoot to enhance joint flexibility and movement, has been developed to assist elderly people and individuals with walking impairments. Despite its widespread acceptance and positive reception in some care settings, the precise impact of this device on gait dynamics remains unexplored. This study aims to bridge this gap by comparing the walking speeds of healthy volunteers using the e-foot® against their normal walking speeds. Furthermore, it seeks to elucidate the biomechanical alterations induced by the e-foot® on their gait patterns. In this intervention study, 51 healthy volunteers underwent a 10-m walk test, both with and without the e-foot®, to measure its effect on walking speed. Gait changes were biomechanically compared by analyzing marker positions and accelerations of the lower extremities during the walk tests. The e-foot® orthotic device significantly improved walking times for both men and women in the 10-m walk test. Biomechanical testing showed a consistent trend of higher marker positions of the knees, heels, and toes when participants were using the e-foot®. Additionally, marker acceleration during the first half of the swing phase was greater with the e-foot®, indicating a faster gait initiation. The e-foot® increased the walking speed of healthy volunteers. Also, there were changes to knee, heel and toe positions during gait, and comparative increase in acceleration was recorded in these three parts during swinging gait.

The Influence of Resistance Training on Joint Flexibility in Healthy Adults: A Systematic Review, Meta-analysis, and Meta-regression.

Favro, F, Roma, E, Gobbo, S, Bullo, V, Di Blasio, A, Cugusi, L, and Bergamin, M. The influence of resistance training on joint flexibility in healthy adults: A systematic review, meta-analysis, and meta-regression. J Strength Cond Res XX(X): 000-000, 2024-Joint flexibility is a key component of physical fitness. Despite the large body of evidence regarding the effectiveness of muscle stretching exercises, little is known about the effect of resistance training on flexibility. A systematic search was conducted on 9 academic search instruments; inclusion criteria were as follows: healthy adult participants (age ≥18 years); resistance training intervention (duration ≥4 weeks); at least one flexibility outcome. Risk of bias was assessed using the RoB-2 and ROBINS-I tools. A 3-level meta-analysis was conducted, with multiple outcomes nested within each study. A moderator analysis was conducted by fitting a meta-regression model. Significance level was set at p < 0.05. We included 36 studies (1,469 participants). None of the included papers resulted at a low risk of bias. The pooled effect size for resistance training on flexibility was g = 0.6325, with 95% CI: 0.4762 to 0.7888 (p < 0.0001). There was a substantial amount of heterogeneity between studies. Exercise intensity was a significant moderator (p < 0.0225, high vs low), based on 129 and unique effect sizes, and sex (p = 0.0429). Activity level and age were nonsignificant moderators. Resistance training could be implemented as a strategy to improve joint flexibility, with high-intensity protocols resulting in a magnified effect. However, the high overall risk of bias and substantial heterogeneity limit our ability to draw definitive conclusions.

Prehabilitation: A Smoother Pathway to Surgery

Prehabilitation, a proactive approach involving physical, psychological, and nutritional preparation, has gained recognition as a critical component of orthopedic surgery care. This structured intervention aims to optimize a patient’s functional capacity prior to surgery, facilitating faster recovery and improved outcomes. Research demonstrates that prehabilitation enhances muscle strength, joint flexibility, and cardiovascular endurance, mitigating the loss of physical function during the postoperative phase. It also reduces the risk of complications, shortens hospital stays, and improves overall patient satisfaction. By addressing psychological factors such as anxiety and fear, prehabilitation contributes to mental readiness, which can influence recovery trajectories. This review explores the evidence supporting prehabilitation, outlines effective strategies tailored to orthopedic patients, and highlights its role in reducing healthcare costs. Integrating prehabilitation into standard preoperative protocols presents a promising opportunity to transform orthopedic care and improve patient outcomes.

NOVEL METHODS, MODELS, AND METRICS FOR MEDICARE DATA TO UNDERSTAND RECOVERY AFTER HOSPITALIZATION FOR INJURY

Abstract Medicare is the U.S. federal health insurance program for adults aged ≥65 years and some younger persons with specific conditions. The Medicare Minimum Data Set (MDS) is a standardized clinical assessment tool administered by the Centers for Medicare and Medicaid Services to facilitate care management for residents in Medicare and Medicaid certified nursing homes. Medicare administrative claims and MDS databases provide opportunity to generate novel and impactful real-world evidence, but deriving accurate conclusions can be difficult due to measurement and research design challenges. In this symposium, we illustrate four methods to overcome these challenges in the context of understanding mechanisms of post-hospitalization recovery among older adults, consistent with meeting theme “The Fortitude Factor”. First, we describe a new data science method to overcome unmeasured confounding when identifying factors associated with post-hospitalization monthly days at home (DAH), a person-centered metric that reflects aging in place, among older adults with Alzheimer’s Disease and Related Dementia (ADRD) who experience a hip fracture. We next examine the role of contextual socioeconomic disadvantage in recovery from hip fracture using weighting estimation to mitigate survival bias. To overcome bias from informative observation times in the MDS, we apply a flexible joint model to examine time-varying factors associated with post-fracture physical function among older adults with ADRD. Lastly, we innovatively apply latent variable analysis to identify post-hospitalization DAH trajectories among older adults with traumatic brain injury. We discuss how the gerontology community can use these bias-reducing approaches for policy-relevant health research with Medicare data.

Physical fitness at work and its relationship with cardiovascular, respiratory and metabolic health. A systematic review

The relationship between physical fitness and work capacity is an important determinant of workers' health, influencing productivity and well-being. Objective: To assess the existing knowledge on the relationship between cardiovascular, respiratory and metabolic health with the components of physical fitness (including aerobic and muscular fitness, joint flexibility and balance) and physical activity. Methods: Through a systematic review carried out between August and October 2023, using academic databases to identify relevant articles that analyzed the interrelationship between physical fitness, cardiovascular disease risk factors and work performance. Results: Five articles were retrieved suggesting that promoting physical fitness and managing cardiovascular disease risk factors are essential to improving workers' work performance, productivity and longevity. Conclusion: The importance of physical fitness and management of cardiovascular disease risk factors in workers' work performance is shown. Greater cardiorespiratory fitness and flexibility were shown to be associated with a lower incidence of musculoskeletal injuries, suggesting that regular physical activity, both aerobic and anaerobic, has a protective effect on musculoskeletal and cardiovascular health.

Bayesian semiparametric inference in longitudinal metabolomics data

The article is motivated by an application to the EarlyBird cohort study aiming to explore how anthropometrics and clinical and metabolic processes are associated with obesity and glucose control during childhood. There is interest in inferring the relationship between dynamically changing and high-dimensional metabolites and a longitudinal response. Important aspects of the analysis include the selection of the important set of metabolites and the accommodation of missing data in both response and covariate values. With this motivation, we propose a flexible but parsimonious Bayesian semiparametric joint model for the outcome and the covariate generating processes, making novel use of nonparametric mean processes, latent factor models, and different classes of continuous shrinkage priors. The proposed approach efficiently addresses daunting dimensionality challenges, simplifies imputation tasks, and automates the selection of important predictors. Implementation via an efficient Markov chain Monte Carlo algorithm appropriately accounts for uncertainty in various aspects of the analysis. Simulation experiments illustrate the efficacy of the proposed methodology. The application to the EarlyBird cohort study illustrates its practical utility in enabling statistical integration of different molecular processes involved in glucose production and metabolism. From this study, we were able to show that glucose levels from 5 to 16 years of age are associated with different circulating levels of metabolites in the blood serum and can be fitted over time for a wide range of shapes of trajectories. The metabolites contributing the most to explaining glucose trajectories tend to be involved in different central energy metabolomic pathways. The methodology provides a tool to generate new hypotheses related to obesity and glucose control during childhood and adolescence.

The Effect of Clinical Exercise Training on Plantar Pressure, the Subtalar Joint, and the Gait Cycle in Pregnant Women: Randomized Clinical Trial.

Background/Objectives: This study aims to examine the effects of clinical exercise training on foot plantar pressure, the subtalar joint, and the gait cycle during pregnancy. Methods: The study was planned as a randomized, controlled, and single-blind study. Participants' demographic information, obstetric evaluation, physical activity level, fall history, and pain evaluation were recorded. Foot plantar pressure, the subtalar joint, and the gait cycle were measured through pedobarography at Gait Laboratory. The control group was recommended walking. Clinical exercise training was given to the study group 2 days a week for eight weeks. Evaluations were made on day 0 and the day corresponding to the end of week 8. Results: The study was completed with 50 people in the study group (age: 29.7 ± 3.8 years) and 51 in the control group (age: 29.1 ± 6.1 years). As a result of the parametric and non-parametric tests performed before and after the exercise, it was observed that there was a statistically significant difference between the two groups in weight, BMI, pain score, static plantar pressure, dynamic plantar pressure, subtalar joint flexibility, duration of the walking period, and multistep walking speed (p < 0.01). The two groups had a significant difference only in the dominant midfoot plantar pressure (p > 0.05). Conclusions: According to our research, weight control and pain relief are observed in women who engage in clinical exercise in the second trimester of pregnancy; plantar pressure and subtalar joint flexibility are preserved, the walking period does not increase, and the multistep walking speed can be maintained after eight weeks.

Trajectory Tracking of a 2-Degrees-of-Freedom Serial Flexible Joint Robot Using an Active Disturbance Rejection Controller Approach

Trajectory Tracking of a 2-Degrees-of-Freedom Serial Flexible Joint Robot Using an Active Disturbance Rejection Controller Approach

Design of an Underactuated, Flexure-Based Gripper, Actuated Through a Push–Pull Flexure

Abstract The design of grippers for the agro-industry is challenging. To be cost-effective, the picked object should be moved around fast requiring a firm grip on the fruit of different hardnesses, shapes, and sizes without causing damage. This article presents a self-adaptive flexure-based gripper design optimized for high acceleration loads. A main novelty is that it is actuated through a push–pull flexure that is loaded in tension when the gripper closes, allowing it to handle high actuation forces without the risk of buckling. To create a robust gripper that can handle relatively high loads, flexures are used that are reinforced and have a thickness variation over the length. The optimal thickness distribution of these flexures is derived analytically to facilitate the design process. The derived principles are generally applicable to flexure hinges. The resulting advanced cartwheel flexure joint, as used in this gripper, has a 2.5 times higher support stiffness and a 1.5 times higher buckling load when compared to a conventional cartwheel joint of the same size and actuation stiffness. The PP-gripper is numerically optimized for a high pull-out force, using analytical design insights as a starting point. The gripper can grip circular objects with radii between 30 and 40 mm. The pull-out force is 21.4 N, with a maximum actuation force of 100 N. Good correspondence is found between the geometric design approach, the numerically optimized design, and the results of the experimental validation.