Prototype Design and Efficiency Analysis of a Novel Robot Drive Based on 3K-H-V Topology

Robot actuators directly affect the performance of robots, and robot drives directly affect the performance of robot actuators. With the development of robotics, robots have put higher requirements on robot drives, such as high stiffness, high accuracy, high loading, high efficiency, low backlash, compact size, and hollow structure. In order to meet the demand development of robot actuators, this research base proposes a new robot drive based on 3K-H-V topology using involute and cycloidal gear shapes, planetary cycloidal drive, from the perspective of drive topology and through the design idea of decoupling. In this study, the reduction ratio and the efficiency model of the 3K-H-V topology were analyzed, and a prototype planetary cycloidal actuator was designed. The feasibility of the drive is initially verified by experimentally concluding that the PCA has a hollow structure, compact size, and high torque density (69 kg/Nm)

Bibliometric and visualization analysis of matrix metalloproteinases in ischemic stroke from 1992 to 2022

BackgroundMatrix metalloproteinases (MMPs) are important players in the complex pathophysiology of ischemic stroke (IS). Recent studies have shown that tremendous progress has been made in the research of MMPs in IS. However, a comprehensive bibliometric analysis is lacking in this research field. This study aimed to introduce the research status as well as hotspots and explore the field of MMPs in IS from a bibliometric perspective.MethodsThis study collected 1,441 records related to MMPs in IS from 1979 to 2022 in the web of science core collection (WoSCC) database, among them the first paper was published in 1992. CiteSpace, VOSviewer, and R package “bibliometrix” software were used to analyze the publication type, author, institution, country, keywords, and other relevant data in detail, and made descriptive statistics to provide new ideas for future clinical and scientific research.ResultsThe change in the number of publications related to MMPs in IS can be divided into three stages: the first stage was from 1992 to 2012, when the number of publications increased steadily; the second stage was from 2013 to 2017, when the number of publications was relatively stable; the third stage was from 2018 to 2022, when the number of publications began to decline. The United States and China, contributing more than 64% of publications, were the main drivers for research in this field. Universities in the United States were the most active institutions and contributed the most publications. STROKE is the most popular journal in this field with the largest publications as well as the most co-cited journal. Rosenberg GA was the most prolific writer and has the most citations. “Clinical,” “Medical,” “Neurology,” “Immunology” and “Biochemistry molecular biology” were the main research areas of MMPs in IS. “Molecular regulation,” “Metalloproteinase-9 concentration,” “Clinical translation” and “Cerebral ischemia–reperfusion” are the primary keywords clusters in this field.ConclusionThis is the first bibliometric study that comprehensively mapped out the knowledge structure and development trends in the research field of MMPs in IS in recent 30 years, which will provide a reference for scholars studying this field

Clinical Features in Juvenile-Onset Ankylosing Spondylitis Patients Carrying Different B27 Subtypes

Background. Ankylosing spondylitis (AS) is a common rheumatic disease and is characterized by inflammation of the axial skeleton. HLA-B27 is strongly associated with AS. Juvenile-onset AS (JAS) with disease onset before 16 years of age differs from adult-onset AS (AAS) in many respects. Objective. To compare the clinical features in JAS with different B27 subtypes and analyze the differences between JAS and AAS. Methods. 145 JAS and 360 AAS patients were included. The demographic data, clinical manifestations, laboratory markers, Bath AS indices, and B27 subtypes were recorded. Results. Peripheral arthritis, enthesitis, BASDAI, ESR, and CRP were significantly higher in JAS patients with HLA-B*2704 than those with B27-negative. Enthesitis and ESR were significantly higher in patients with HLA-B*2705 than those with B27-negative. The onset age of HLA-B*2715 group was much earlier than the other groups. The peripheral arthritis, enthesitis, and hip joint involvement in JAS with HLA-B*2704 were significantly higher than those in AAS with HLA-B*2704. Conclusion. JAS with different B27 subtypes had similar features in most of manifestations; JAS and AAS patients with the same subtype could have distinctive courses. Early diagnosis, hip detection, and control of systemic active inflammation in JAS patients will be helpful for improving the prognosis

Multi-parameter control-based operation strategy for mainstream deammonification in an integrated anaerobic biofilm reactor-step feed MBR

The mainstream deammonification of municipal wastewater has been recognized as one of the greatest challenges in wastewater engineering. The conventional activated sludge process has disadvantages of high energy input and sludge production. To tackle this situation, an innovative A-B process, where an anaerobic biofilm reactor (AnBR) functioned as the A stage for energy recovery, and a step-feed membrane bioreactor (MBR) functioned as the B stage for mainstream deammonification, was constructed for carbon-neutral wastewater treatment. For addressing the challenge associated with selective retention of ammonia-oxidizing bacteria (AOB) over nitrite oxidizing bacteria (NOB), a multi-parameter control-based operation strategy was developed with synergistic control of influent COD redistribution, dissolved oxygen (DO) concentration and sludge retention time (SRT) in the innovative AnBR - step-feed MBR system. Results showed that more than 85% of wastewater COD could be removed with the direct production of methane gas in the AnBR. A relatively stable partial nitritation, which is a prerequisite of anammox, was achieved with the successful suppression of NOB, leading to 98% of ammonium-N and 73% of total nitrogen removed. Anammox bacteria could well survive and enrich in the integrated system, and the contribution of anammox to the total nitrogen removal was more than 70% at optimal conditions. Reactions network involved in the nitrogen transformation in the integrated system was further constructed through the mass balance and microbial community structure analyses. Consequently, this study demonstrated a practically feasible process configuration with high operation and control flexibility towards stable mainstream deammonification of municipal wastewater.National Research Foundation (NRF)This work is supported by a grant from the Singapore's National Research Foundation under Urban Solutions & Sustainability, which is administered by PUB, Singapore's national water agency

Robust adaptive multi-task tracking control of redundant manipulators with dynamic and kinematic uncertainties and unknown disturbances

<p>In this paper, a novel adaptive multi-priority controller for redundant manipulators is proposed to accomplish the multi-task tracking when kinematic/dynamic uncertainties and unknown disturbances exist. Prioritized redundancy resolution in kinematic level is incorporated into this passivity-based control framework. The kinematic and dynamic parameter adaptations are driven by both tracking error and prediction error. Moreover, the tracking information from both primary and subtasks are all utilized to accelerate the parameter estimation when the tasks are independent, whereas the inevitable tracking error of the subtasks due to algorithmic singularities is properly eliminated in the adaptation laws when the tasks are dependent. Potential ill-conditioned solution of the pseudoinverse is avoided using an improved singularity-robust inverse of the projected Jacobian. Along with the improvement of the multi-task tracking performance, smoothness of the commanded torques is still guaranteed for easy application. Measurements of the noisy joint acceleration and task velocity are avoided. The controller is mathematically derived based on Lyapunov stability analysis. Simulation results of the two cases are presented to verify the effectiveness and superiority of the proposed controller.</p