Joint Deformity Research Articles

Clinical Evaluation of the Role of Singhasyadi Kwatha in the Management of Vatarakta (Gout)

Vatarakta is a disease where both Vata and Rakta are afflicted by distinct etiological factors. Vatarakta is a Vatapradhana Tridoshaja Vyadhi in which Rakta is main Dushya. In modern science, it corresponds to gout. While synthetic drugs offer quick relief, they often cause adverse reactions. As a result, many are turning to Ayurveda, which has effective formulations for Vatarakta and a proven track record, providing hope for better relief to those suffering. Aims: Clinical evaluation of ‘Singhasyadi Kwatha’ in the management of Vatarakta (gout). Materials & Methods: In this interventional clinical trial, the purpose is to assess the treatment efficacy of Singhasyadi Kwatha for Vatarakta (gout). The study involves a randomized allocation of 30 patients into a single group with open label masking. The assignment is parallel, determined through computer-generated randomization. The study follows a prospective timeline with a total study period of 30 days for each patient. There is preparatory period of 7 days followed by 45 days treatment period. After completion of treatment, participants were monitored during a follow-up period occurring every 15 days to evaluate both efficacy and safety of the intervention. Result: Overall, the drug exhibited significant relief for several key symptoms including Sandhi Shoola (pain in joints), Sandhi Shotha (swelling of joints), Vidaha (burning sensation), Raga (redness), Toda (pricking sensation), Twakvaivarnya (discoloration of skin), Vikriti (deformity of joints). Although all the symptoms didn’t show statistically significant improvement, the findings of study collectively demonstrate the positive impact of the drug on Vatarakta symptoms highlighting its potential as a therapeutic intervention for the condition under investigation. Conclusion: this research emphasizes the importance of utilizing traditional herbal remedies in treating non communicable conditions like Vatarakta. This herbal formulation can serve as potent alternatives or complementary options alongside modern medications, showcasing their effectiveness in managing the disease.

The effect of welding deformation on the equivalent structural stress of dissimilar girth welded joint

Weld distortion refers to the phenomenon of shrinkage around the weld seam and warping of the outer weldment edges. This leads to a deviation from the original straight force transfer path in the joint, resulting in higher stress concentration. The weld root's stress concentrations can cause significant fatigue issues in dissimilar girth welded joints. However, previous evaluation methods have generally overlooked the impact of the welding process on fatigue assessment. To address this gap, this paper proposes integrating welding deformation into the fatigue life calculation process for welded joints made of G20Mn5 cast steel. In this study, a welding calculation program was developed to accurately simulate joint deformation using a two-curvature conical heat source model. Subsequently, high-frequency fatigue test data from scaled specimens of four types of joints were analyzed. The original equivalent structural stress fatigue data were corrected by taking into account the initial condition of weld deformation. This correction resulted in a reduction in the scatter of the fatigue data. Furthermore, the study also analyzed the welding deformation differences and the dispersion of stress concentration in scaled specimens caused by welding inhomogeneity.

Study of the effect of crystal orientation on the mechanical response and fatigue life of solder joints under thermal cycling by crystal plasticity

Electronic products are subjected to thermal cycling caused by power cycling in service processes. Owing to the difference in the coefficients of thermal expansion (CTEs) of solder joints and other packaging materials, solder joints suffer from thermomechanical fatigue, and cracks appear at their bonding interfaces. Solder joints are usually a single grain or three grains with Beachball morphology, and their composition is Sn-based Pb-free SAC305 (96.5Sn–3.0Ag–0.5Cu wt.%) solder, which exhibits obvious anisotropic mechanical behavior. This study investigated a thermal cycling simulation of Plastic Ball Grid Array (PBGA) packaging, in which the Anand model was used for solder joints, and the outermost solder joint was found to be a dangerous point. Sub-models were then established for this solder joint with several typical crystal orientations. The effect of crystal orientation under thermal cycling was simulated using thermomechanical crystal plasticity. When the c-axis of Sn crystal was perpendicular to the substrate, the deformation resistance was the largest, and the accumulation of equivalent plastic strain and strain energy dissipation was the slowest; hence, the fatigue life was the longest. As the angle between the c-axis and the substrate decreased, the deformation accumulated faster. When the c-axis was parallel to the substrate, the deformation of the solder joint was the fastest, and thus this joint was the first to fail and had the shortest fatigue life. In addition, the simulation of three grains indicated that orientations and their distributions had an influence on the shear strain accumulation of slip systems and fatigue life.

Primary total knee arthroplasty in hemophilic arthropathy

Advanced hemophilic knee arthropathy is a frequent and devastating manifestation of severe hemophilia with significant implications for activities of daily living. Hemophilic arthropathy is caused by repeated bleeding, resulting in joint degeneration, pain, deformity and disability. In patients with hemophilia and advanced disease, total knee arthroplasty (TKA) has proven to be the most successful intervention, improves physical function and reduces knee pain. Hemophilic patients carry additional risks for complications and required specific pre/postoperative considerations. Expert treatment center should be used to improve patient outcome. Hemophilic patients present significant surgical challenges such as joint destruction, bone loss, severe ankylosis and oligoarticular involvement. The surgeon performing the arthroplasty must be experienced to manage such problems.

Symposium 3

Systemic sclerosis (SSc) remains a refractory condition with poor functional and survival outcomes. This is attributable primarily to the extremely diverse clinical course and distribution of organ involvement. The pathogenesis of SSc includes microangiopathy and chronic inflammation, leading to accumulation of extracellular matrix and resultant irreversible fibrosis resulting in distortion of the normal tissue architecture. This pathogenic process is analogous to that observed in rheumatoid arthritis, in which persistent synovitis leads to articular cartilage and bone destruction, resulting in functional impairment due to joint deformity. Therefore, successful experiences in developing treatment strategies in patients with rheumatoid arthritis can also be applied to SSc. These include early diagnosis and intervention, treat-to-target strategy aiming at achievement of clinical remission or low-disease activity, prediction of disease progression and prognosis, and disease modification by pharmacologic treatment. Immunosuppressants targeting lymphocytes, including mycophenolate mofetil and cyclophosphamide, have been the mainstream of the treatment of SSc, based on treatment evidence showing prevention of decline in forced vital capacity, promotion of improving modified Rodnan skin thickness score, and improved patient-reported outcomes. However, survival benefit has not been shown in long-term follow-up of patients treated with non-specific immunosuppressants. Recently, drugs targeting a variety of molecules involved in the pathologic process of SSc, such as tocilizumab and nintedanib, have been shown to prevent progression of certain organ involvement in clinical trials, resulting in expanding treatment options. Implementation of those potential disease-modifying therapies in management of SSc requires adequate assessment of disease activity and treatment goal setting. In addition, clinical characteristics that predict the progression of organ manifestations, such as skin sclerosis and interstitial lung disease, need to be identified as prognosis factors. Like other rheumatic diseases, early interventions have been shown to be more effective than delayed intervention. This lecture features current standings and challenges of treat-to-target strategy in SSc patients.

Progressive Pseudo-Rheumatoid Dysplasia a Rare Genetic Musculoskeletal Condition Causing Crippling Disability in a Young Boy- a Case Report

Progressive pseudo-rheumatoid dysplasia (PPRD) is an uncommon genetic condition inherited in an autosomal recessive mode caused by a mutation in the WNT1-inducible signaling pathway protein 3 (WISP3) located on chromosome 6q21. In this condition, the articular cartilage gradually deteriorates, causing severe discomfort, stiffness, and joint deformities with a relatively high prevalence in Middle Eastern countries. Camptodactyly and platyspondyly are the standard features found in this condition. We present a very young boy diagnosed with bilateral hip dysplasia during early childhood and developing increasing pain, stiffness and deformities in the hands, elbow, hips, knee, and ankle. The diagnosis was suspected based on characteristic clinical and radiological features. The diagnosis was confirmed by genetic testing and the absence of elevated serum inflammatory markers. He was born out of a consanguineous marriage, and his parents were unaffected. They are three siblings; his elder sister has a milder condition, while his elder brother is unaffected. There were no adverse events during pregnancy. Birth weight was within normal limits, met all developmental milestones on time, and had no significant past medical history. Compounded by hip dysplasia, he developed a severe disability and had to undergo joint replacement surgery at a very young age. PPRD should be suspected in children from Middle Eastern countries of 3-8 years of age who present with multiple joint pain and stiffness and are born out of inbred family marriages. Diagnosis can be suspected by the characteristic clinical and radiological features coupled with the absence of raised serum inflammatory markers and confirmed by genetic testing. Genetic counseling and pre-marriage testing are of valuable help in prevention.

Assessing risk for complications in acute hematogenous osteomyelitis in children. Validation of two predictive scores.

Acute hematogenous osteomyelitis (AHO) can be associated with severe complications which can be difficult to predict in the clinical setting. The previously published predictive acute complication score ("A-SCORE") and chronic complication score ("C-SCORE") show promise, however, further external validation is needed. We performed a retrospective study of 418 children with AHO and analyzed the performance of A-SCORE (variables included bone abscess, fever after 48 hours of starting antibiotics, suppurative arthritis, disseminated disease and delayed source control) to predict risk for acute complicated course (treatment failure, prolonged admission, and/or need for ≥ 2 bone debridements) and C-SCORE (includes disseminated disease, bone debridement and CRP ≥10mg/dl at 2-4 days after starting antibiotics) to predict chronic complications (growth restriction, pathologic fracture, chronic osteomyelitis, avascular necrosis, joint deformity and/or frozen joint). An acute complicated course occurred in 106/418 (25.4%); 51/380 (13.5%) with complete follow-up data had a chronic complication. The A-SCORE performed with similar specificity (78%) and negative predictive value (NPV) (92%), and higher sensitivity (81%) and increased area under the receiver operating curve (AUC) (0.87) in our population. The C-SCORE performed with similar sensitivity (64%) and NPV (94%) but had lower specificity (86%) and AUC (0.71) than originally reported. Other variables associated with development of complications such as tibia involvement and bacteremia ≥ 2 days were identified but did not result in significantly improved predictive scores. Predictive A-SCORE and C-SCORE for AHO complications in children may help guide acute management and long-term follow up decisions. Prospective studies are needed to determine their applicability.

Combination of curcumin and catalase protects against chondrocyte injury and knee osteoarthritis progression by suppressing oxidative stress

Knee Osteoarthritis (KOA) is an age-related progressive degenerative joint disease, which is featured with pain, joint deformity, and disability. Accumulating evidence indicated oxidative stress plays a crucial role in the occurrence and development of KOA. Curcumin is a polyphenolic compound with significant antioxidant activity among various diseases while catalase (CAT) is an enzyme degrading hydrogen peroxide in treating oxidative diseases. We previously showed that the expression of CAT was low in cartilage. However, the combination of curcumin and CAT in KOA is still elusive. In this study, we demonstrated that the combination of curcumin and CAT has the potential to inhibit the IL1β-induced chondrocyte apoptosis without cytotoxicity in vitro. Mechanistically, we found that the synergistic application curcumin and CAT not only promotes curcumin's regulation of the NRF2/HO-1 signaling pathway to enhance antioxidant enzyme expression to remove superoxide radicals, but also CAT can further remove downstream hydrogen peroxide which enhances the ability to scavenge reactive oxygen species (ROS). In vivo, studies revealed that combination of curcumin and catalase could better inhibit oxidative stress-induced chondrocyte injury by promoting the expression of ROS scavenging enzymes. In sum, the combination of curcumin and catalase can be used to treat KOA. Thus, combination of curcumin and catalase may act as a novel therapeutic agent to manage KOA and our research gives a rationale for their combined use in the therapeutic of KOA.

How Do the Morphological Abnormalities of Femoral Head and Neck, Femoral Shaft and Femoral Condyle Affect the Occurrence and Development of Medial Knee Osteoarthritis.

At present, the main viewpoint is that tibial varus is the main reason of medial knee osteoarthritis (OA), and high tibial osteotomy (HTO) is also the main alignment correction method to correct medial knee OA. In contrast, the impact of the anatomical alignment of the femur on medial knee OA is often overlooked. We evaluated the increased risk for medial knee OA because a varus alignment could be attributed to the anatomical reasons that include hip anatomy, femoral shaft bowing (FSB) and femoral condylar dysplasia. The present research adopted a cross-sectional study method. We selected 62 patients with HTO in the Third Hospital of Hebei Medical University from June 2021 to March 2022 as the HTO group and 55 healthy volunteers as the control group. Femoral neck-shaft angle (NSA), lateral FSB, mechanical lateral distal femoral angle (mLDFA) and hip-knee-ankle (HKA) was radiographically examined within the two groups. The femoral neck length and offset were also measured, and the ratio is represented by the ratio of the femoral neck length to off-set (N/O). The 2-tailed Student t-test was used to compare the differences between groups when the data were in accordance with a normal distribution. Otherwise, the Mann-Whitney U tests was used to compare the differences between groups. Compared to the control group, the HTO group had a higher offset (p < 0.05), greater femoral neck length (p < 0.05), and decreased (more varus) NSA (p < 0.05). The HKA in the HTO group was 172.20 ° (3.50°), which was significantly lower than that of the control group 177.00° (3.05°), (p < 0.001), while the medial OA was associated with more varus HKA. The mean mLDFA was 89.10 ° (2.35°) and 87.50° (2.85°) in the HTO and control groups (p < 0.005), respectively. The mean lateral FSB values of the full-length radiographs were larger (p < 0.001) in the HTO group (4.24° ± 3.25°) than that in control group (1.16° ± 2.32°). The reduction of NSA (coxa vara) and the increase of the mLDFA can lead to medial knee OA, while the lateral FSB also affects medial OA. We believe that femoral deformity is also one of the cause of the medial knee OA. Therefore, it is necessary to evaluate the joint deformity of the femur and tibia before surgery in order to determine whether to use HTO alone to correct the lower limb alignment.

The Influence of Pipe Thickness on the Quality of Welded Joints

In this article, we aim to investigate the effect of pipe thickness on the deformation of welded joints in tubular structures. To this end, pipes with a diameter of 60 mm and a length of 215 mm will be utilized in both simulation and experimental processes. The Tungsten Inert Gas (TIG) welding method, known for its high-quality welds, will be employed to join the two steel pipes. The study will be conducted with four different pipe thicknesses: 2.5 mm, 3.2 mm, 4.0 mm, and 5.2 mm, to cover a wide range of thicknesses commonly used in industrial applications. In addition, to validate the accuracy of the simulation method, experimental tests will be carried out for selected simulated cases. The results of the study indicate that structures with thinner pipe walls exhibit higher residual temperatures and stresses, which leads to more deformation. Therefore, it is crucial to consider the pipe thickness when designing and welding tubular structures. After comparing the deformation results obtained from both simulation and experimental tests, we conclude that the simulation method is an effective tool for predicting the deformation of welded joints in tubular structures. By utilizing simulation methods, engineers can optimize the welding parameters and select the appropriate pipe thickness to minimize deformation and ensure the structural integrity of tubular structures.

Analysis of mechanical performance of modular steel-concrete composite joints considering floor slab composite effects

This study establishes and verifies the finite element models (FEM) of MSCCJs to analyze the mechanical performance of modular steel–concrete composite joints (MSCCJs) under monotonic static load without considering the floor slab composite effect (FSCE). Subsequently, 12 MSCCJ models incorporating the FSCE are constructed using ABAQUS. The study evaluates the effects of varying column axial compression ratios (n = 0.15, 0.25, 0.4, 0.6), floor width (w = 800, 1200 mm), floor thickness (t = 90, 110, 120 mm), and floor reinforcement ratio (r = 6 %, 8 %, 12 %) on the bending moment, initial stiffness (k0), ductility, and stress transfer of the joints. The results indicated that as n increases, the shear stress concentration in the joint core module (JCM) and the steel framework at the lower column end become more pronounced. Concurrently, the bearing moment and k0 of the joint also increase. However, once n surpasses 0.4, the joint's plastic properties diminish upon damage. With an increment in w, the k0 and ductility deformation of the joint remain stable and then decline. At w = 1000 mm, the joint's bearing capacity, stress distribution, and deformation performance reach their optimum. Since it significantly impacts stress distribution, its effect on the joint's mechanical performance is minimal. Lastly, the value of r enhances the ductility of MSCCJs and the stress concentration in the reinforcement. It is advisable to maintain r between 1.1 % and 1.7 %.

The Diagnostic Significance of Serum Sclerostin in Early Detection of Rheumatoid Arthritis in Syrian Patients

Background: Rheumatoid arthritis (RA) is associated with joint deformities and local bone erosions. Sclerostin is an inhibitor of the Wnt pathway and drives to reduce bone formation. Aims: Our study aimed to compare the diagnostic significance of sclerostin with anti-CCP (anti-cyclic citrullinated peptide; normal level&lt;20 IU/ml, and rheumatoid factor (RF; normal level&lt;16 IU/ml) for the early diagnosis of rheumatoid arthritis in Syrian patients. Methods: This study contained fifty-eight RA patients and thirty healthy individuals who were equally age- and sex-matched. Serum sclerostin and serum anti-CCP (IgG) levels were evaluated by using the enzyme-linked immunosorbent assay (ELISA). RA activity was assessed based on disease activity scores (DAS28). Results: Our results indicated that serum levels of sclerostin levels were higher in the RA group than in the healthy group (p&lt;0.001). There was a positive correlation between serum sclerostin and DAS28-ESR (r=0.413, p=0.001). By ROC curve, the most optimal cut-off value of sclerostin was 249.69 pg/ml (AUC was 0.910 with 95% confidence interval (CI) values (0.852-0.969), sensitivity of 87.9%, and specificity of 93.3%) [Odds Ratio (OR) and P-value: 102, P&lt; 0.0001]. In RA patients, the sensitivity and specificity of anti-CCP were 74.1% and 90%, and 70.6% and 86.6% of RF, respectively. Conclusion: Increased serum sclerostin may aid as a new prognostic biomarker for evaluating the activity of RA. Sclerostin showed higher sensitivity and specificity than anti-CCP and RF-IgM antibodies. Therefore, sclerostin is a sensitive and specific biomarker for early diagnosis of rheumatoid arthritis.

Robot-assisted knee arthroplasty: first experience (a prospective randomized study)

Introduction Primary total knee arthroplasty has long been proven effective in the treatment of stage 3–4 knee osteoarthritis. It is well known that this intervention not only improves the quality of life, but also helps to restore the function of the joint and eliminate axial deformities.Purpose To compare early results of total knee arthroplasty using robot-assisted technology with conventional manual technique.Materials and Methods 20 patients diagnosed with stage 3 osteoarthritis of the knee joint and varus deformity of the knee joint axis were included in a prospective randomized study. Patients were divided into 2 representative groups, 10 subjects underwent robot-assisted knee arthroplasty, and the conventional manual technique was used in the other 10 patients. For clinical assessment, functional scales KSS, WOMAC, Lysholm Score were used, postoperative radiographs were evaluated.Results According to clinical functional scales, 10 days after surgery, there was an improvement in performance in the patients of both groups (p &lt; 0.05); the duration of the operation in the patients of both groups did not differ in general; intra-operative blood loss in the group with robot‑assisted arthroplasty was lower; and assessment of postoperative results by radiological imaging showed a better component positioning according to preoperative planning in the robotic group.Discussion When the operation is performed by experienced surgeons, one can expect the correct position of the components and the balance of the ligamentous apparatus in standard arthroplasty. However, the use of robot-assisted technology provides a secure intervention performance even at a hospital where a small number of such operations is performed.Conclusion Despite the high cost and the need for additional consumables, robot-assisted arthroplasty has a number of advantages over classical manual techniques. These advantages include: accurate restoration of the limb axis even in extra-articular deformities, correct position of the endoprosthesis components, reduction of intraoperative blood loss due to closed medullary canals, and safety for patients. However, the role of the surgeon in such operations remains paramount, as it is the surgeon who is responsible for planning the operation, performing it, and achieving soft tissue balance.

Analysis of High-Speed Rotor Vibration Failure Due to Sudden Angular Deformation of Bolt Joints

As the efficiency of advanced aero engines improves, the operational speed of their rotors increases. This heightened operational speed makes the rotor dynamics highly sensitive to changes in the rotor’s mass asymmetry state, or unbalance state. During the use of a dual-spool turbofan engine, when its supercritical high-pressure rotor (HPR) exceeds a certain operational speed, the rotor’s vibration spikes and continues to increase with the operational speed until it drops sharply near the maximum operational speed. Analysis of the bolt joints in the faulty rotor reveals various phenomena such as joint interface damage, changes in bolt loosening torque distribution, and alterations in rotor initial unbalance. This paper proposes that at high operational speeds, the bolt joint of the HPR undergoes sudden angular deformation, resulting in the slanting of the principal axis of inertia of the turbine disk. This slant leads to changes in the unbalanced state of the HPR. The additional unbalance causes a sudden rotational inertia load excitation, triggering the rotor vibration failure. Subsequently, a rotor dynamic model that incorporates the angular deformation of the joints is established to simulate how this joint deformation influences the dynamic response of the rotor. The simulation results align well with the observed failure phenomenon and validate the proposed failure mechanism. Finally, troubleshooting measures are proposed and implemented in the faulty engine, effectively mitigating the vibration fault.

UNICONDYLAR KNEE ARTHROPLASTY — PROS AND CONS (LITERATURE REVIEW)

In the modern world, despite the increased availability of hightech orthopedic care, the number of patients with gonarthrosis does not decrease, and thanks to public awareness, more and more people turn to orthopedists for surgical help. Due to its high efficiency, the leading role in the treatment of terminal gonarthrosis has been firmly occupied by total knee arthroplasty for more than four decades. Unicondylar knee arthroplasty in patients with unilateral arthrosis allows to largely preserve physiological kinematics, to achieve minimal bone and soft tissue traumatization during surgery and, as a result, to obtain a higher functional result. The objective of the work is to analyze the data of the world literature regarding unicondylar knee arthroplasty, its advantages and disadvantages. Material and methods. The authors analyzed the publications devoted to single-condylar knee arthroplasty from the Google search engine, scientific and metric electronic databases PubMed, Medline and other relevant sources of scientific and medical information. Correct patient selection is vital to ensure a successful outcome with OEKS. The main indication for OEKS is deforming arthrosis of the II–III century. with a predominant lesion of the internal part of the knee joint and varus deformation of the lower limb or with a more pronounced pathology of the external part of the knee joint and valgus deformation of the lower limb. Results. The authors analyzed the literature sources on single-condylar endoprosthesis of the knee joint. Indications, contraindications, biomechanical features, type of endoprosthesis fixation, type of endoprosthesis platform, features of lateral gonarthrosis, and complications of single-condylar knee arthroplasty are determined. Conclusions. The analysis of selected literary sources showed that single-condylar arthroplasty of the knee joint is an effective means of preserving the bone. However, careful patient selection and precision of surgical technique remain the key to a successful outcome.

Kinesthetic treatment on stiffness, quality of life and functional independence in patients with rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disease of unknown etiology that primarily affects the joints, causing joint destruction, deformity and functional disability. Genetic, immunological, environmental, psychological and endocrine factors are believed to contribute to its development. The diagnosis of RA is based on the confrontation of clinical manifestations and laboratory tests, with classification criteria established by the American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR). Treatment has evolved significantly in recent years, focusing on obtaining and maintaining clinical remission to prevent structural and systemic complications. Rehabilitation plays a crucial role in the management of RA, relieving pain, preventing deformities and improving quality of life. Physical therapy programs include joint mobility exercises, resistance exercises, therapeutic massage, aerobic exercises and stretching, among others. RA can have different patterns of evolution, such as acute, cyclic or progressive. Physiotherapy helps to improve the physical and psychological function of patients, adapting to the stages of the disease. In addition, a multidisciplinary approach including pharmacological treatment, orthopedic surgery when necessary and personal care is recommended. Rehabilitation is essential to maintain the functional independence of RA patients and improve their quality of life. Physical therapy programs should be tailored to the individual needs of each patient and consider the stage of the disease. Physiotherapy has been shown to reduce pain, improve muscle function and strength, and contribute to the overall well-being of RA patients

An Overview of Flexible Jointed Robots

Background: Since the first industrial robots were created in the middle of the last century, robotics has shown strong growth prospects. Robotics has developed rapidly over time and is being used in more and more areas. Because of the need to minimize impact forces during robot movement, traditional rigid robots are no longer sufficient, flexible joints are more adaptable to the environment due to their adjustable stiffness and have higher application value in humancomputer interaction. Therefore, flexible jointed robots have become one of the research hotspots in recent years. Objective: Through a detailed analysis of the existing hardware and software control technologies of flexible joint robots, referring to papers and recent patents on flexible jointed robots, we aim to find ways to reduce the impact of flexible joint deformation of flexible joint robots and improve the overall force and position control accuracy of flexible joint robots. Methods: To categorize the hardware and software technologies of flexible jointed robots, to briefly explain the directions of the technologies categorized and to study them, to summarize the advantages and disadvantages of each type of technology respectively, and to outlook the future development trend. Results: Through the study and analysis of the various parts of the flexible joint robot, it can be seen that joint flexibility is mainly achieved through the drive motor and flexible components to achieve flexibility and then through the fusion control technology to control the deformation of the joint. Differences in structural materials affect the mechanical properties of robot motion. The detection and feedback accuracy of the sensor also has a significant impact on the control accuracy. Conclusion: The use of new motor technology, flexible component technology, material technology, and sensor technology, combined with improvements in software fusion control technology can reduce the impact of joint deformation, improve the control accuracy of joint flexibility, and achieve high-precision force-level control capability of flexible joint robots.

Analytical homogenization for equivalent in-plane elastic moduli of multi-material honeycombs

3D printable multi-material honeycombs have attracted increasing interest recently due to the improved elastic moduli, buckling and energy absorption properties. This paper proposes an analytical homogenization for the equivalent in-plane elastic moduli (EIEM) of multi-material honeycombs. First, the axial and bending stiffness of a cantilever beam consist of three sections made of different materials is formulated. Then based on unit cell method and cantilever beam model, the closed-form expressions of EIEM are proposed by fully considering the deformations of both joints and cell walls with arbitrary stiffness, which are sufficiently general to be applied to hexagonal, auxetic and rectangular multi-material honeycombs and validated very well by numerical simulations and experiments. Furthermore, the effects of geometric and material distribution ratios on EIEM are discussed. The results show that the geometric and material distribution ratios of inclined cell wall have a significant effect on all five EIEM while that of vertical cell wall shows a significant effect on shear modulus but only a slight effect on y- direction elastic moduli. Compared with single-material honeycombs, changing joint stiffness has a significant effect on the equivalent Young’s moduli and shear modulus but a slight effect on Poisson’s ratios.

Improving mechanical properties and durability of polyether sealant in prefabricated buildings with titanium dioxide and graphene

The silane-modified polyether sealant is widely applied to fill the gaps between external walls in prefabricated buildings and to bear the deformation of joints. However, the weak tensile strength and poor ultraviolet and moisture resistance of sealant lead to severe degradation, posing threat to the building waterproofing and safety. To address the problems, titanium dioxide and graphene were adopted to improve the mechanical properties and durability of sealant. The tack-free time, tensile properties, ultraviolet resistance, and hydrophobic performance of pristine and modified sealant were investigated and the enhancement and erosive resistance mechanisms of modified sealant were revealed by microscale characterization. Results indicated that modified sealant with low content of titanium dioxide had greater tensile strength and ultraviolet resistance. The crystalline form of titanium dioxide and produced Si-O bond enhanced the ultraviolet resistance. Moreover, the 0.8% graphene-modified sealant possessed superior moisture resistance with 23% increased contact angle. Graphene increased the surface roughness and generated π-conjugated structure, improving sealant hydrophobicity. It is revealed that the enhanced properties were ascribed to the spatial structure of fillers and chemical bond energy. This work provides a novel sealant with high ultraviolet resistance and hydrophobicity, facilitating the development of durable and low-maintenance prefabricated buildings.

Flexible, highly sensitive and reliable piezocapacitive pressure sensor with honeycomb-like microarchitecture fabricated using filament-processed mold

Highly sensitive flexible pressure sensors have been extensively studied due to their promising applications in many fields. Various sensing mechanisms have been proposed to convert pressure into a readable electrical signal, among which piezocapacitive presents advantages due to its simple structure and convenient integration. The modification of the dielectric layer composing these sensors is a common strategy to improve their sensing performance. In this paper, we propose the fabrication of a novel capacitive-based flexible pressure sensor with honeycomb-like microarchitecture by using femtosecond laser filament based far-field technique. The fabricated flexible sensing device is assembled face-to-face with two layers of micro-structured polydimethylsiloxane thin films that is duplicated from laser filament-processed silicon mold. The as-prepared flexible sensor features excellent sensing performance with high reliability, and enables detection of multi-modal signals, including pressure, proximity, and bending. Owing to the advantages mentioned above, the obtained flexible pressure sensor can be attached on non-planar human skin to monitor the physiological signals as well as joint deformation during exercise, revealing it great application potential in cutting-edge fields, such as robotic tactility.