Desired Speed Research Articles

Experimental and statistical damage analysis in milling of S2‐glass fiber/epoxy and basalt fiber/epoxy composites

AbstractS2‐glass fiber reinforced plastics (S2‐GFRP) and basalt fiber reinforced plastics (BFRP) have emerged as crucial materials due to their exceptional mechanical properties, and milling of composite materials plays an important role in achieving desired properties. However, they have proven challenges due to relative inhomogeneity compared with metals, resulting unpredictability in quality of milling operations. The objective of this work is to investigate the effect of cutting parameters, tool geometry and tool surface materials on the surface quality of composites using burrs as a metric. S2‐GFRP and BFRP composites were produced by the vacuum infusion method. Helical and straight flute end mills were manufactured from high‐speed steel (HSS) and carbide rounds, and half of them were coated with titanium nitride using reactive magnetron sputtering technique. Taguchi L18 orthogonal array is used to determine the effect of tool material, tool angle, coating, cutting direction, spindle speed, and feed rate on the machining quality of S2‐GFRPs and BFRPs with respect to burr formations. Milling experiments were conducted under dry conditions and then the burrs were imaged to calculate the total area and length. Statistical analysis was also performed to optimize the machining parameters and tool type for ensuring the structural integrity and performance of the final composite parts. The results showed that the selection of tool material has the most significant impact on the burr area and length of the machined surface. The novel image analysis allows to analyze the extent of the burr size with a desirable operation speed for industrial applications.Highlights Aerospace grade S2‐Glass (S2‐GFRP) and basalt fiber reinforced plastics (BFRP) were manufactured. Carbide and HSS end mills were fabricated and coated with titanium nitride protective layer. FRPs were machined at various process parameters designed by Taguchi method. Distinctive image processing was firstly used to compute milling induced Burr area and length. Statistical analysis was performed to quantify the contribution of parameters and optimize milling.

Attentive multi-granularity perception network for person search

Person search is an extremely challenging task that seeks to identify individuals through joint person detection and person re-identification from uncropped real scene images. Previous studies primarily focus on learning rich features to enhance identification. However, arbitrary feature enhancement strategies may introduce unwanted background noise. Moreover, different scenarios usually exhibit varying pedestrian appearances or even intricate occlusions, leading to inconsistent/incomplete pedestrian features in different images. In this paper, we introduce a novel Attentive Multi-granularity Perception (AMP) module seamlessly integrated into our AMPN network. This module specifically addresses appearance variations and occlusions within a person's Region of Interest (RoI). The AMP module harnesses discriminative relationship features from various local regions, significantly enhancing identification accuracy. It comprises two principal components: the Pedestrian Perception Enhancement (PPE) block and the Background Interference Suppressor (BIS). The PPE block introduces a Spatial-wise Feature Mixer and a Channel-wise Feature Mixer, which effectively capture and refine discriminative relation features. Simultaneously, the BIS operates in parallel with the PPE block, enriching the discriminative relation features and enhancing the distinctiveness between the foreground and background. Our AMP module is plug-and-play and can integrate with other person search models. Extensive experiments validate our model's merits, achieving state-of-the-art performance on CUHK-SYSU and a 4.8% mAP gain over SeqNet on PRW at a desirable speed. Our code is accessible at https://github.com/zqx951102/AMPN.

Optimal design of diversion dams based on Upgraded Multi-Objective Particle Swarm Optimization (UMOPSO)

In the present research, the application of the Upgraded Multi-Objective Particle Swarm Optimization (UMOPSO) algorithm is investigated with the aim of reducing concreting costs through minimizing the diversion dam weight function. At the time of using optimization algorithms, regarding the nature of such a;gorithms and the research problem, making changes in algorithm running steps is necessary. Hence, in the current study, making some changes in the UMOPSO algorithm develops it to solve multi-objective optimization problems by considering their problem restrictions. In this paper, the study diversion dam is the Nazelian dam located in Kermanshah, Province, Iran. The decision variables in the optimization problem include the height of upstream and downstream cut off walls, the length and the thickness of the upstream concrete bed and the thickness of the stilling basin. By considering the initial population (n = 15), the optimal answer is achieved in iteration 100 and after algorithm run 1500. In this study, considering that the objective function should be evaluated for five decision variables with infinite possible values on a discrete range for each variable, the general result of the present study emphasizes on the desirable efficiency and speed of the UMOPSO algorithm in finding the optimal answer of the diversion dam optimal design problem which shows the strength of this algorithm.

Barrier-Function-Based Adaptive Fast-Terminal Sliding-Mode Control for a PMSM Speed-Regulation System

Barrier-function-based adaptive fast-terminal sliding-mode control approaches have been devised to enhance the precision of speed regulation of permanent magnet synchronous motors (PMSMs). Firstly, the speed loop utilizes fast-terminal sliding-mode control, which contributes to a faster convergence rate and enhances the robustness of the system. By adopting this control technique, the system can quickly reach the desired speed setpoint and effectively handle disturbances. Secondly, an adaptive law based on the barrier function is employed to adjust the control gain adaptively. The proposed adaptive law considers the magnitude of the disturbance and effectively mitigates chattering resulting from excessive switching gain. Unlike conventional control methods, the design of the adaptive fast-terminal sliding-mode control does not require attaining the upper limit of the lumped disturbances. Experimental results are presented to validate the proposed approach. These results demonstrate that the proposed method outperforms the conventional terminal sliding mode control technique in terms of handling both external and internal disturbances.

Three-Dimensional Path Tracking of Over-Actuated AUVs Based on MPC and Variable Universe S-Plane Algorithms

Autonomous Underwater Vehicles (AUVs) are widely used for the inspection of seabed pipelines. To address the issues of low trajectory tracking accuracy in AUV inspection processes due to uncertain ocean current disturbances, this paper designs a new dual-loop controller based on Model Predictive Control (MPC) and Variable Universe S-plane algorithms (S-VUD FLC, where VUD represents Variable Universe Discourse and FLC represents Fuzzy Logic Control) to achieve three-dimensional (3-D) trajectory tracking of an over-actuated AUV under uncertain ocean current disturbances. This paper uses MPC as the outer-loop position controller and S-VUD FLC as the inner-loop speed controller. The outer-loop controller generates desired speed instructions that are passed to the inner-loop speed controller, while the inner-loop speed controller generates control input and uses a direct logic thrust distribution method that approaches optimal energy consumption to distribute the thrust generated by the propellers to the over-actuated AUV, achieving closed-loop tracking of the entire trajectory. When designing the outer-loop MPC controller, the actual control input constraints of the system are considered, and control increments are introduced to reduce control model errors and the impact of uncertain external disturbances on the actual AUV model parameters. When designing the inner-loop S-VUD FLC, the strong robustness of the variable universe fuzzy controller and the easy construction characteristics of the S-plane algorithm are combined, and integral action is introduced to improve the system’s tracking accuracy. The stability of the outer loop controller is proven by the Lyapunov method, and the stability of the inner loop controller is verified by simulation. Finally, simulations show that the over-actuated AUV has fast tracking processes and high tracking result accuracy under uncertain ocean current disturbances, demonstrating the effectiveness of the designed dual-loop controller.

DSP based space vector PWM control for solar electric vehicle

Solar Electric Vehicles (SEV) are considered the future vehicles to solve the issues of air pollution, global warming, and the rapid decreases of the petroleum resources facing the current transportation technology. However, SEV are still facing important technical obstacles to overcome. They include batteries energy storage capacity, charging times, efficiency of the solar panels and electrical propulsion systems. Solving any of those problems and electric vehicles will compete-complement the internal combustion engines vehicles. In the present work, we propose an electrical propulsion system based on three phase induction motor in order to obtain the desired speed and torque with less power loss. Because of the need to lightweight nature, small volume, low cost, less maintenance and high efficiency system, a three phase squirrel cage induction motor (IM) is selected in the electrical propulsion system. The IM is fed from three phase inverter operated by a constant V/F control method and Space Vector Pulse Width Modulation (SVPWM) algorithm. The proposed control strategy has been implemented on the texas instruments TM320F2812 Digital Signal Processor (DSP) to generate SVPWM signal needed to trigger the gates of IGBT based inverter. The inverter used in this work is a three phase inverter IRAMY20UP60B type. The experimental results show the ability of the proposed control strategy to generate a three-phase sine wave signal with desired frequency. The proposed control strategy is experimented on a locally manufactured EV prototype. The results show that the EV prototype can be propelled to speed up to 60km/h under different road conditions.

Implementation and Synthesis of Math Library Functions

Achieving speed and accuracy for math library functions like exp, sin, and log is difficult. This is because low-level implementation languages like C do not help math library developers catch mathematical errors, build implementations incrementally, or separate high-level and low-level decision making. This ultimately puts development of such functions out of reach for all but the most experienced experts. To address this, we introduce MegaLibm, a domain-specific language for implementing, testing, and tuning math library implementations. MegaLibm is safe, modular, and tunable. Implementations in MegaLibm can automatically detect mathematical mistakes like sign flips via semantic wellformedness checks, and components like range reductions can be implemented in a modular, composable way, simplifying implementations. Once the high-level algorithm is done, tuning parameters like working precisions and evaluation schemes can be adjusted through orthogonal tuning parameters to achieve the desired speed and accuracy. MegaLibm also enables math library developers to work interactively, compiling, testing, and tuning their implementations and invoking tools like Sollya and type-directed synthesis to complete components and synthesize entire implementations. MegaLibm can express 8 state-of-the-art math library implementations with comparable speed and accuracy to the original C code, and can synthesize 5 variations and 3 from-scratch implementations with minimal guidance.

Development of a microcontroller and resistive touchscreen-based speed monitoring and control system for DC motor

<span>Speed control is a key requirement in direct current (DC) motor applications where accuracy, reliability, flexibility, and safety are of high importance. In this study, a microcontroller and resistive touchscreen-based DC motor speed monitoring and control system were developed. The core components employed in the development of the system include Arduino ATMega328P microcontroller, thin film technology (TFT) resistive touch screen, L293D motor driver, and infrared (IR) sensor module. ATMega328P microcontroller is the brain of the system around which the overall circuit design was modeled. TFT resistive touch screen displays the motor speed and also, enables the users to set a desired speed. L293D motor driver regulates the voltage and current supplied to the motor, and a feedback loop comprising an IR sensor module ensures the maintenance of the motor speed at the desired level. A performance test was conducted on the developed system to ascertain its correct functionality. The developed speed monitoring and control system operated satisfactorily during testing; achieving a speed control in the range of 800 to 3000 rpm. The developed device is useful and can be scaled up for various domestic and industrial applications.</span>

Pedestrian behaviour in integrated street designs: A mesoscopic analysis

Recent trends in urban design have called for more equal treatment of all road users and have effected a shift away from the traditional concept of segregation and towards more integration. This usually translates to more pedestrian-friendly layouts with wider footways, fewer protective guardrails and lower (or even no) kerbs. Following-on from previous research on the topic, this study explores changes in pedestrian behaviour in response to integrated street design. A “mesoscopic” level of analysis is adopted, whereby the actions and revealed choices of individual pedestrians are modelled probabilistically, but without a detailed investigation into their attitudes and perceptions. Video footage from London’s Exhibition Road site during periods before and after its conversion from a conventional layout to a more integrated pedestrian-oriented design is used, and an observation scheme focusing on pedestrian actions and discernible characteristics is devised. Inferential statistics methods are used to derive models expressing two behavioural traits: walking/crossing speed, and crossing on red incidence. The results suggest that the additional space provided and the reduced crowding post-redevelopment results in pedestrians walking less hastily and close to their desired speed, while the friendlier conditions created by the street layout increase their confidence to enter the road space and cross, sometimes even on a red signal. In particular, those walking alone (rather than in a group) and walking to work (rather than leisure) appear to walk faster and are also more likely to cross on red.

Oat (Avena sativa L.) In Vitro Cultures: Prospects and Challenges for Breeding

Plant in vitro cultures have been a crucial component of efforts to enhance crops and advance plant biotechnology. Traditional plant breeding is a time-consuming process that, depending on the crop, might take up to 25 years before an improved cultivar is available to farmers. This is a problematic technique since both beneficial qualities (such as pest resistance) and negative ones (such as decreased yield) can be passed down from generation to generation. In vitro cultures provide various advantages over traditional methods, including the capacity to add desirable characteristics and speed up the development of new cultivars. When it comes to oat (Avena sativa L.), the efficient method of plant regeneration is still missing compared to the most common cereals, possibly because this cereal is known to be recalcitrant to in vitro culture. In this review, an effort has been made to provide a succinct overview of the various in vitro techniques utilized or potentially involved in the breeding of oat. The present work aims to summarize the crucial methods of A. sativa L. cultivation under tissue culture conditions with a focus on the progress that has been made in biotechnological techniques that are used in the breeding of this species.

Analisis Pengaruh Aktivitas Pasar Tradisional Marisa Terhadap Kinerja Ruas Jalan Sultan Amai Kecamatan Marisa Kabupaten Pohuwato

The aim of this research is to determine the influence of Marisa Traditional Market activities on the performance of Marisa District Roads, Pohuwato Regency. The research was carried out at the Marisa Traditional Market, Jalan Sultan Amai, Marisa District, Pohuwato Regency using data analysis, namely vehicle volume (Q), free flow speed (Fv), capacity (C), degree of saturation (DS) and service level. The research results show that the vehicle volume at the morning peak hour is 373.53 vehicles/hour. The vehicle volume during the afternoon peak is 363.27 vehicles/hour and in the afternoon it is 450.10 vehicles/hour. Traffic speed (Fv) is 37.04 km/hour. The capacity value (C) is 2,249.84 pcu/hour. The degree of saturation (DS) value was 0.16 for the first day of observation, 0.17 for the second day of observation and 0.20 for the third day of observation. From the degree of saturation value, the level of service (LoS) value is obtained, namely A. Based on the characteristics of the level of service, this means free flow, low volume and high speed. The driver can choose the desired speed.

Improved social force model considering the influence of COVID-19 pandemic: Pedestrian evacuation under regulation

Collective behavior has been frequently studied in previous works. However, during pandemics, the method in which system dynamics control the collective behavior of pedestrians has rarely been studied. To further understand this issue, an improved social force model is proposed in this paper to explore the potential constraints caused by pandemics during pedestrian evacuations. During COVID-19, Regulatory authorities usually require pedestrians to keep a certain social distance from each other to avoid virus infection. Our model can characterize the feature that pedestrians are sensitive to surrounding pedestrians within this prescriptive social distance. Based on the simulated results in an ordinary room, the effects of prescriptive social distance, behavioral response times and other potential factors on evacuation efficiency are compared to reflect the changes caused by COVID-19. The main findings are as follows. (1) Trying to maintain a social distance of 1.5 m will not delay evacuations but instead promote overall process of evacuations. Under the appropriate desired speed, a win‒win situation between epidemic safety and evacuation efficiency can be achieved. (2) The increase in prescriptive social distance under a high desired speed will slightly promote evacuations. When the desired speed is too low, however, it may substantially reduce evacuation efficiency. (3) The response time reflects the epidemic sensitivity of pedestrians. For pedestrians in congestion, a high response time value indicates a longer social distance adjustment, which will have a certain inhibitory effect on evacuation efficiency. (4) The presence of epidemic-sensitive pedestrians can effectively inhibit the “faster-is-slower effect”. This work will help managers formulate relevant evacuation plans by taking advantage of the balance between personal purpose of fast evacuation and the public regulations, thereby inhibiting the spread of COVID-19 without lowing evacuation efficiency.

Microscopic Simulation Model for Motorcycle Dominated Networks: A Case Study of a VISSIM Simulation Model for a Mixed Traffic Corridor

Microscopic traffic simulation packages, which were invented for car-based environments, have also been used for motorcycle-based environments. Because the interactions between several transport modes (e.g., buses, cars, and motorcycles) are different in these two environments, default parameters relating to these modes (e.g., acceleration, deceleration, speed) should be modified in the simulation of motorcycle-dominated networks. However, there seems to be very little evidence on the modification of these parameters in microscopic traffic simulation for these networks. To fill this gap in the literature, this research develops a VISSIM model (as one of the most appropriate microscopic simulation packages) for motorcycle-dominated mixed transport, which includes data collection, creation of a VISSIM model, and calibration and validation processes. For parameters which cannot be observed on-site, some values for each parameter are chosen based on the default values in VISSIM or local conditions. These values are then run in VISSIM models and tested in the calibration and validation processes to choose the values that best describe vehicle movements. By contrast, parameters that might be collected on-site are statistically analysed and inserted directly in to VISSIM. Acceleration and deceleration of motorcycles, the desired speed of car and bus, the desired speed of motorcycle, minimum lateral distance driving when overtaking vehicles on the same lane, and average standstill distance were applied for developing VISSIM models for a motorcycle-dominated mixed traffic corridor in Hanoi, Vietnam. Acceleration and deceleration surveys were carried out on-site by using the speed gun Stalker ATS. The results of statistical tests prove that the VISSIM models are sufficiently reliable to represent real traffic. Transport modellers can draw on the findings of this study. Desired acceleration and deceleration default values in VISSIM, which are for typical motorcycles used in Europe, should be replaced by local acceleration and deceleration rates. The methodology for developing a VISSIM model can be modified to suit other local motorcycle-dominated mixed traffic conditions.

Comparative simulation study of electric motors for high performance of 3D printers

3D printing is a process in which material is joined layer by layer under computer control to make a 3D object easy to get almost any shape. This technology finds applications in various fields and it is attracting considerable interest from industry and academia. There are many different brands and models of motors used in 3D printers, and they all vary in quality and effectiveness. In this article we present the principal of the 3D printer, types of motors used in 3D printer and mathematical modelling of this motors like brushless direct current (DC) motor, permanent magnet synchronous motor (PMSM), and stepper motor. The models of analytical equations describing the three systems of motors are evaluated and developed by Matlab/Simunlink. In this paper, we have conducted a comparison of the series of results from simulation between the performance of PMSM, brushless DC and stepper motor. Among several criteria, this simulation study allows to select the criterion of response time to reach the desired speed and the precision of the rotor position to choose the most performant motor for 3D printers.

Periodic intermittent cruise control: An innovative approach for reducing fuel consumption and exhaust emissions in road traffic systems

Motor vehicle exhaust emission has become an important source of global atmospheric emissions, and the urgency of protection and management of this issues has become increasingly prominent. The cooperative control strategy of road vehicles can comprehensively manage the individual vehicles from the whole perspective, which is a powerful means to achieve the goal of dual carbon goal. In the preliminary stage of the IoV, limited communication bandwidth increases the difficulty of designing the above cooperative cruise control scheme. To solve this problem, we designed a new novel periodic intermittent cruise controller to track and assess the real-time operating status and relevant environmental indicators of road vehicles. Compared with the previous continuous controller, the proposed controller subdivides the time domain into each sub-period, and the controller is activated merely during the working time interval of each period, which can effectively reduce the control cost. Besides, when the leading vehicle state changes, the following vehicle can quickly respond to the above adjustment and track the leading vehicles with the new desired speed and headway, thereby reduce the duration time and amplitude of road vehicle state oscillation. Based on the Lyapunov-like function method, the sufficient condition for the existence of designed periodically intermittent cruise controller is given, which guarantees that the closed-loop error dynamic system is satisfies exponential stable, and the controller gain coefficients in proposed control protocol can be obtained via solving a set of linear matrix inequalities with some commercial software built-in toolbox. At last, based on the VT-Microenvironment experiment evaluation model, we have carried out some numerical simulation experiments, and the results show that the periodic intermittent cruise control protocol is feasible in improving vehicle safety tracking performance, and remain valid in reducing energy consumption and exhaust emissions such as CO, HC, NOx, and approximately decreased by 2.52%, 6.65%, 34.75%, and 15.70% respectively from the rural value. This research result provides a technical reference to road traffic safety and environmental assessment.

Investigating the dynamic influence of passive effects on undulatory locomotion in viscous environment and unleashing the potential of hybrid friction

This study encompasses the passive interdependence of body material (internal damping, stiffness, and geometry) and environmental (frictional anisotropy and frictional coefficients) properties on the performance and adaptability of undulatory locomotion. Undulatory locomotion is modeled in viscous and hybrid environments. The body’s ability to adapt passively results in different locomotion gaits, such as swimming and crawling. Results show that, in swimming gaits, body stiffness dominates frictional forces, whereas in crawling gaits, frictional forces dominate body stiffness. Our result showed that the interdependence between endogenous and exogenous dynamics can be utilized to achieve the desired speed. The hybrid frictional environment is modeled as the combination of dry and viscous frictions and recognized as a valuable asset in the modeling of undulatory locomotion in granular media. In the hybrid environment the respective ratios of dry and viscous frictions play an essential role in the speed optimization. The optimal combination of dry and viscous frictions can be found depending on the characteristics of the body and environment. We validate the viscous based frictional model using the properties of the body of Caenorhabditis Elegans from the state of the art, in a viscous environment. The results can be employed to design robotic solutions to perform optimally in different environments and with customized body properties.

Power loss scaling laws of high-speed planetary reducers

Scaling laws are increasingly recognized as an interesting solution to accelerate the early stages of the development of drivetrains. Concerning gearboxes, prior studies focused on geometric scaling to achieve new desired torque and speed values and to predict mass, volume, and inertia. Power loss scaling laws are still lacking in literature. This paper seeks to bridge this gap by proposing scaling laws for the power loss of high-speed planetary reducers. Due to the lack of reliable information on the losses at high-speed, scaling laws are derived from an experimental campaign of 5 commercial planetary speed reducers. The proposed scaling laws are defined based on high-level specifications of the drivetrain, namely the maximal input speed, output torque, and gear ratio. The results suggest that the derived scaling laws can predict the efficiency and power losses with an average error of less than 1%, and 8% respectively relative to the measurements, considering a torque scaling factor of up to 4, speed scaling factor of up to 0.6 and gear ratio scaling factor of up to 2.

Design and simulation of a wall-climbing robot car using 3D printing technology and the vacuum method

This paper presents a novel approach to building a vertical wall-climbing robot using the vacuum method and the internal contact model. By leveraging advanced 3D printing technology, the proposed robot model addresses three key challenges encountered in previous studies: achieving high traction force for smooth and efficient movement, ensuring low roughness and fast shifting capability, and minimizing production costs for mass deployment. The vacuum suction method employs an air compressor to generate suction force, enabling the robot to ascend walls vertically. This process significantly increases airflow velocity, creating a low-pressure area that enhances adhesion to the surface. The utilization of 3D printing technology allows for the creation of the robot’s bodywork and essential components, facilitating adjustments in the mechanical system design. The developed robot is well-suited for inspecting and maintaining hazardous areas in tall buildings and conducting surveillance in factory settings. Moreover, it proves valuable for cleaning and monitoring slippery surfaces with minimal roughness. The research findings demonstrate that incorporating 3D printing technology in the design and construction of wall-climbing robots has successfully achieved the desired speed and grip capabilities.

Method for Selecting the Vehicles That Can Enter a Street Network to Maintain the Speed on Links above a Speed Threshold

The introduced method is a proposal for detecting spaces (links) and times (90 s periods) where the average speed is below the desirable, and for selecting vehicles in those spaces and times so that vehicles are systematically and gradually reduced from one simulation to another until we get a simulation presenting the desirable average speed in all space and time. With our method can be detected the specific vehicles that can enter a street network so that the average speed on the network’ links be always greater than a speed threshold. The speed on a segment is calculated from two perspectives: (1) the general speed (vg), calculated with measurements and estimates, used to estimate the links’ travel times for selecting the vehicles routes, (2) the particular speed (vp), calculated without estimates and for segments with traffic light only with measurements performed during an interval of the green time, used to identify links and periods of unacceptable (low) speed. We test our method with different origin-destination (OD) tables, for each OD table we obtain the number of vehicles that can enter the network in 1 h so all links and periods present acceptable speed. Another result was, for each link, the change of the average (and of the standard deviation) of VG (the vector containing the vg of each period) between the final (after our method) and initial (the traffic conditions without our method) simulations, therefore the percentages of the links presenting a convenient change were evidenced. We did the same with VP (the vp of each period).

An Approach for DC Motor Speed Control with Off-Policy Reinforcement Learning Method

In the literature, interest in automatic control systems that do not require human intervention and perform at the desired level increases day by day. In this study, a Twin Delay Deep Deterministic Policy Gradient (TD3), a reinforcement learning algorithm, automatically controls a DC motor system. A reinforcement learning method is an approach that learns what should be done to reach the goal and observes the results that come out with the interaction of both itself and the environment. The proposed method aims to adjust the voltage value applied to the input of the DC motor in order to reach output with single input and single output structure to the desired speed.