Linear and nonlinear arx model for intelligent pneumatic actuator systems

System modeling in describing the dynamic behavior of the system is very important and can be considered as a challenging problem in control systems engineering. This article presents the linear and nonlinear approaches using AutoRegressive with Exogenous Input (ARX) model structure for the modeling of position control of an Intelligent Pneumatic Actuator (IPA) system. The input and output data of the system were obtained from real-time experiment conducted while the linear and nonlinear mathematical models of the system were obtained using system identification (SI) technique. Best fit and Akaike’s criteria were used to validate the models. The results based on simulation reveals that nonlinear ARX (NARX) had the best performance for the modeling of position control of IPA system. The results show that nonlinear modeling is an effective way of analyzing and describing the dynamic behavior and characteristics of IPA system. This approach is also expected to be able to be applied to other systems. A future study exploring the execution of other model structures in demonstrating the position control of IPA system would be exceptionally intriguing

Cognitive Factors and Gender Related to Self-reported Difficulties in Older Drivers

The purpose of this study is to determine the association between selfreported driving difficulties among older drivers and scores on specific cognitive tests. A cross-sectional study of 38 car drivers (22 men and 16 women), aged 61- 81 was carried out. The participants were volunteers recruited from two senior universities and a university health program for older drivers, in the area of Lisbon, Portugal. A battery of visual, psychomotor and cognitive measures was undertaken with a questionnaire about driving difficulties in a sample of healthy older adults. Difficulties in driving were the dependent variable in this study, defined as any reported difficulty in ≥ 4 driving situations. After a multivariate analysis, the independent factors significantly associated with driving difficulties were divided attention subtest of UFOV® (p=0.013), number of trials with success in the Tower of London (p=0.015) and gender (p=0.021). The drivers that reported difficulties in ≥ 4 driving situations made significantly less trials with success in the Tower of London test, had lower performances in divided attention between central and peripheral targets, and were more frequently females. Results suggest that planning ability, divided visual attention and gender are three important factors to be considered in the analysis of driving difficulties. However, further investigation with additional cognitive tests and driving measures (staterecorded crashes, driving simulator and on-road driving performance) could be developed in order to understand the factors related to driving difficulties in healthy older drivers

Long-Legged Hexapod Giacometti Robot Using Thin Soft McKibben Actuator

This letter introduces a lightweight hexapod robot, Giacometti robot, made with long and narrow legs following the Alberto Giacometti's sculpture conception. The goal is achieved by, first, using multiple links with thin and soft McKibben actuators, and second, choosing a leg design which is narrow in comparison to its body's length and height, unlike conventional robot design. By such design characteristic, the leg will exhibit elastic deformations due to the low stiffness property of the thin link structure. Then, we model the leg structure and conduct the deflection analysis to confirm the capability of the leg to perform walking motion. The high force to weight ratio characteristics of the actuator provided the ability to drive the system, as shown by a static model and further validated experimentally. To compensate for the high elastic structural flexibility of the legs, two walking gaits namely customized Wave gait and Giacometti gait were introduced. The robot could walk successfully with both gaits at maximum speed of 0.005 and 0.05 m/s, respectively. It is envisaged that the lightweight Giacometti robot design can be very useful in legged robotic exploration

PDMS-based dual-channel pneumatic microactuator using sacrificial molding fabrication technique

This paper presents a novel polydimethylsiloxane-based dual-channel bellows-structured pneumatic actuator, fabricated through sacrificial molding technique. A finite element analysis was performed to find the optimum structure and analyze the bending performance of the square-bellows actuator. The actuator was fabricated using acrylonitrile butadiene-styrene-based sacrificial mold to form the channel and bellow structures with an overall actuator size of 5 × 5 × 27.6 mm3. The experimental validation has revealed that the actuator attained a smooth bi-directional bending motion with maximum angles of -25° and 35° and force of -0.168 and 0.212 N under left and right channel actuation, respectively, at 100 kPa pressure. Hence, the state-of-the-art dual channels square-bellows actuator was able to achieve an optimum bi-directional bending with low input pressure, which would push the boundaries of soft robotics towards the development of more safe and flexible robotic surgical tools

Optimizing the preference of student-lecturer allocation problem using analytical hierarchy process and integer programming

This paper focuses on solving a student-lecturer allocation problem by optimizing declared preferences. Typically, many students undertake an internship program every semester and many preferences need to be taken when assigning students to lecturer for supervision. The aim is to maximize student’s total preference. Analytic Hierarchy Process (AHP) technique is used in ranking the preference criteria and alternatives to form a preference matrix. Then, an Integer Programming (IP) model is developed by considering related constraints, which involves lecturer capacity according to academic position and matching gender of student to lecturer. This study demonstrates the effectiveness of using AHP technique in prioritizing preference criteria and facilitates finding the best solutions in the context of multiple criteria by using preference matrix. The IP model shows that all constraints are satisfied, and students’ total preferences is maximized. The study demonstrates that the proposed method is efficient and avoids biased assignment. The satisfaction of the gender related constraint and preferences toward lecturers contributes significantly to satisfaction among students and staff

Sustainable electrospun materials with enhanced blood compatibility for wound healing applications—A mini review

Wound healing is a complex process that requires an appropriate environment to support healing. Wound dressings play a crucial role in wound management by protecting the wound and promoting healing. Recent advancements in wound dressing technology include the development of bio-absorbable electrospun dressings incorporating essential oils, which have shown promise in enhancing wound healing potential. However, there is still a need for sustainable wound dressing technology that is effective, safe, and environmentally friendly. This review addresses this need by emphasizing the potential of bio-absorbable electrospun wound dressings incorporating essential oils and advocating for a paradigm shift toward sustainable crop-origin materials and the elimination of toxic solvents in wound dressing fabrication

Nonparametric Online Learning Control for Soft Continuum Robot: An Enabling Technique for Effective Endoscopic Navigation.

Bioinspired robotic structures comprising soft actuation units have attracted increasing research interest. Taking advantage of its inherent compliance, soft robots can assure safe interaction with external environments, provided that precise and effective manipulation could be achieved. Endoscopy is a typical application. However, previous model-based control approaches often require simplified geometric assumptions on the soft manipulator, but which could be very inaccurate in the presence of unmodeled external interaction forces. In this study, we propose a generic control framework based on nonparametric and online, as well as local, training to learn the inverse model directly, without prior knowledge of the robot's structural parameters. Detailed experimental evaluation was conducted on a soft robot prototype with control redundancy, performing trajectory tracking in dynamically constrained environments. Advanced element formulation of finite element analysis is employed to initialize the control policy, hence eliminating the need for random exploration in the robot's workspace. The proposed control framework enabled a soft fluid-driven continuum robot to follow a 3D trajectory precisely, even under dynamic external disturbance. Such enhanced control accuracy and adaptability would facilitate effective endoscopic navigation in complex and changing environments

Electrospun porous materials laden with tea tree oil and zinc nitrate exhibiting tailored physicochemical and in vitro apatite formation

Scaffold designs must accommodate the complex regeneration processes of damaged bone tissues. We attempt to achieve this goal by developing a composite electrospun scaffold mimicking the structural and functional requirements of extra cellular matrix This study investigates the use of a novel bone tissue regeneration formulation of tea tree oil (TT) and zinc nitrate Zinc2 incorporated into a polyurethane (PU) nanofibres scaffold fabricated via the well-known electrospinning technique.The diameter of these nanocomposites fibres was smaller (PU/TT-495 ± 184 nm and PU/TT/(ZnNO3)2–409 ± 155 nm) than polyurethane (1099 ± 118 nm) on its own. Fourier transform infrared spectroscopy analysis revealed that the PU and the additives interact through hydrogen-bond formation. Measuring the wettability of the PU/TT indicated a hydrophobic nature (115 ± 2) which was reversed by the addition of (ZnNO3)2 to PU/TT (69° ± 2). TT and the addition of (ZnNO3)2 increased the tensile strength. Atomic force microscopy showed that the fibres of PU/TT (633 ± 297 nm) and PU/TT/(ZnNO3)2 (345 ± 147 nm)were smoother than the PU (854 ± 32 nm). The developed nanocomposites showed delayed blood clot activation and reduced toxicity as determined by anticoagulant studies. Further, bone-forming abilities quantified by in vitro calcium deposition studies indicated enhanced calcium deposition (PU/TT-5.6% and PU/TT/(ZnNO3)2–10.8%) in comparison to PU (2.4%). We have demonstrated that the attributes of these nanocomposites maybe successfully exploited for bone reconstruction

Synthesis, biological evaluation and QSAR studies of diarylpentanoid analogues as potential nitric oxide inhibitors

A series of forty-five 1,5-diphenylpenta-2,4-dien-1-one analogues were synthesized and evaluated for their nitric oxide (NO) inhibition activity in IFN-γ/LPS-activated RAW 264.7 cells. Compounds 3h, 7a, 7d and 7e exhibited comparable or significantly higher activity than the standard, curcumin (IC50 = 14.69 ± 0.24 μM). Compound 7d, a 5-methylthiophenyl-bearing analogue, displayed the most promising NO-inhibitory activity with an IC50 value of 10.24 ± 0.62 μM. The 2D and 3D QSAR analyses performed revealed that a para-hydroxyl group on ring B and an α,β-unsaturated ketone moiety on the linker are crucial for a remarkable anti-inflammatory activity. Based on ADMET and TOPKAT analyses, compounds 3h, 7a and 7d are predicted to be nonmutagenic and to exhibit high blood–brain barrier (BBB) penetration, which indicates that they are potentially effective drug candidates for treating central nervous system (CNS) related disorders