Acceleration Braking Research Articles

Research on Flexible Braking Control of a Crawler Crane during the Free-Fall Hook Process

Due to the large inertia and strong impact accompanying the free-falling hook process of crawler cranes, it is difficult to meet the demand for flexible and smooth braking control under different weight load conditions. Therefore, this paper takes the free-fall hook system as the research object and combines system operation characteristics and control theory to carry out research on flexible braking control of the free-fall hook system. Firstly, a joint simulation platform of MATLAB (version 2018b) and AMESim (version 2019.1) software is built to theoretically analyze the key components of the free-fall hook system (proportional pressure-reducing valve, winch reducer, and wet clutch). Secondly, a mathematical model of the braking process is established, and the pressure control demand is clarified to analyze the reasons for the existence of dead zones and hysteresis loops in the system. Meanwhile, it is found that the dead zones and hysteresis loops existing in the pressure output of the pressure-reducing valve are the main factors of flexibility with load braking. Then, in this paper, a closed-loop control strategy is formulated based on the automatic adaptation of the braking gear in combination with the fuzzy PID pressure. Finally, the effectiveness of the control strategy proposed in this paper is verified with simulation and experimental testing using the pressure hysteresis loop of the free-fall hook process and the load-braking acceleration as the judging criteria. The results show that the system pressure hysteresis loop is reduced by 50%–60% and the maximum braking acceleration is reduced by 24%–30% under the conditions of 6.44 tonnes and 10.44 tonnes, which improves the accuracy of pressure control and achieves flexible and smooth braking with loads for different tonnages of free-fall hooks.

FINDING THE RELATIVE TRAJECTORY OF THE CARGO IN THE BODY OF A VEHICLE WHICH IS GOING DOWN OR UP ON A CURVED SECTION OF THE ROAD

With a certain assumption, the load, which during relative movement along the bottom of the body makes translational movement, can be taken as a material point. In this case, finding the relative movement of the load in the body when the car moves along the road with a spatial axis is reduced to finding the relative trajectory of the material point. In known works, it is proposed to use the accompanying trihedron of the trajectory of the transfer motion and Frenet's formula to find the absolute acceleration vector of a point. The independent variable is not time, as in traditional problems, but the arc coordinate of the transfer trajectory, since only under this condition can Frenet's formulas be applied. The vector of absolute acceleration is obtained in projections onto the vertices of the moving accompanying trihedron, without looking for individual components (transfer, relative, and Coriolis acceleration), as is done in traditional approaches. The purpose of the study is to investigate the relative movement of the load, taken as a material point, along the bottom of the body of a truck moving along a curvilinear section of the road with a spatial axis during its ascent or descent. The spatial curve is characterized by two parameters that depend on the kinematics of the accompanying Frenet trihedron. These parameters are the curvature k and the twist σ of the curve. Their values at any point of the curve will be determined if the dependencies k=k(s) and σ=σ(s) are known, where s is the arc coordinate (the arc length of the curve). It is assumed that such a spatial curve is the axis of a curved section of the road that goes uphill or downhill. The application of the accompanying trihedron of the curve and Frenet's formulas made it possible to describe the relative motion of the cargo in the body of a car moving along a road having a spatial axis with constant and variable speeds. The regularities of the relative movement of the cargo when the car is moving on the road, the axis of which is a helical line with constant curvature and twist, have been found. It was found that there is no significant difference between the value of the relative speed of the cargo when the car moves at a constant speed down or uphill at the initial stage. When braking on a descent, a significant relative movement of the cargo is observed, which increases with an increase in the braking acceleration, and when climbing, on the contrary, the relative movement decreases with an increase in the braking acceleration. The regularity of the relative movement of the cargo when the car moves along the road with variable curvature and torsion of the axis line depends on the type of these dependencies as a function of the length of the arc of the axis line.

Strolling in Room-Scale VR: Hex-Core-MK1 Omnidirectional Treadmill.

The natural locomotion interface is critical to the development of many VR applications. For household VR applications, there are two basic requirements: natural immersive experience and minimized space occupation. The existing locomotion strategies generally do not simultaneously satisfy these two requirements well. This article presents a novel omnidirectional treadmill (ODT) system named Hex-Core-MK1 (HCMK1). By implementing two kinds of mirror-symmetrical spiral rollers to generate the omnidirectional velocity field, this proposed system is capable of providing real walking experiences with a full-degree of freedom in an area as small as 1.76 m 2, while delivering great advantages over several existing ODT systems in terms of weight, volume, latency and dynamic performance. Compared with the sizes of Infinadeck and HCP, the two best motor-driven ODTs so far, the 8 cm height of HCMK1 is only 20% of Infinadeck and 50% of HCP. In addition, HCMK1 is a lightweight device weighing only 110 kg, which provides possibilities for further expanding VR scenarios, such as terrain simulation. The system latency of HCMK1 is only 9ms. The experiments show that HCMK1 can deliver a starting acceleration of 16.00 m/s 2 and a braking acceleration of 30.00 m/s 2.

Research on anti-swing control of tower crane with lifting weight swing function

In order to ensure the accurate positioning of the assembly building, a swing trolley with swing function is designed. In order to solve the swing angle difference generated in the process of adjusting and positioning of the swing trolley, a simplified model is established to analyze the force and establish the relationship between the angular acceleration of the lower lifting beam and the angle of the swing. Secondly, the kinematic analysis is carried out for the rotating pendulum trolley, and its motion model is analyzed under uniform acceleration braking, uniform speed running and uniform deceleration braking. Finally, the angle difference of the rotating pendulum is gradually increasing in the case of different angular acceleration by example. And the variation of the rotating pendulum angle difference in different processes, laying the foundation for subsequent control studies.

Evaluation of Tractor-Trailer Combination Braking Performance in Different Operating Conditions

In the trials of the present work, a double-axle trailer with a carrying capacity of 6 tons and a hydraulically effective mechanical brake were used as a tractor towed car. There is a hydraulic brake system on each axle of the agricultural trailer. In order to separate the brake system on the axles from each other, a hydraulic mechanically controlled 2/2 directional control valve was mounted on both hydraulic brake system inlets. The study was carried out at constant speed (25 km h-1), on stabilized road conditions, with 4 different braking modes and 4 different trailer loads. On stabilized ground, the braking acceleration (deceleration) of the tractor (without trailer) is 5.51 m s-2. The braking acceleration of the combination is 2.15 m s-2 under the condition that the trailer's carrying capacity was 30% more loaded and without brakes, and the braking acceleration of the combination was 3.26 m s-2 when braking on both axles (4 wheels). The deceleration of the combination was above 3.5 m s-2 under the condition of braking on both axles at the rated load of the agricultural trailer, while it was below the standard value in other braking approaches.

Modeling to study the braking efficiency of the electric vehicle

Today, electric vehicles are produced and used a lot for the purpose of reducing environmental pollution. This paper presents the results of research on the braking efficiency of the electric vehicle MG ZS EV. The method of structural separation of the multi-body system is used to establish the braking dynamics model of the electric vehicle. The Newton-Euler equation is used to build the system of dynamics equations of the electric vehicle. Matlab-Simulink software is used to investigate the braking efficiency of the electric vehicle when running at different speeds. If a fully loaded electric vehicle MG ZS EV is running on type B road surface profile according to ISO 8608:2016 at V = [60,80,100]km/h and then braked with maximum braking torque, the braking acceleration of the electric vehicle is a = [6, 6.5, 7.5]m/s2, the yaw angle about the z-axis is ψ = [0.4, 0.7, 0.9]o, the electric vehicle is moving very stably and the braking efficiency of the electric vehicle meets the requirements of ECE-R13 standard.

From uncertainty to further improving the accuracy and authenticity of test results

The article presents new test technologies for assessing the dependability (reliability) of motor vehicles, providing an increase in the accuracy and authenticity of test results through their integrated use with an accentuated allocation of different forms of loading of motor vehicles units and aggregates, in the form of: cyclic regular loading in different frequency ranges, forced loading of the engine and transmission units in the "acceleration—braking" mode and the normalized impact of broken and sodden dirt roads. Keywords: tests, types of tests, new testing technologies, categories of test roads, authenticity, dependability, reliability, accentuated types of loading, acceleration-braking mode, normalized impact of dirt roads

Calculation of Driving Parameters for GOA4 Signaling System using Machine Learning Methods

Among the electromechanical components of the rail system, the rail system vehicle is one of the most important units that carrying the passenger load. In terms of the efficiency of the signalization system, it is very critical to create the optimum vehicle driving profile. While many parameters of the vehicle come into play while designing the driving profile, determining the acceleration and braking accelerations directly affects this characteristic. With the developing technology in rail transportation systems, the use of programmable devices and software instead of human factors is becoming more widespread day by day. Among the software used, artificial intelligence and machine learning applications constitute a large share in the general distribution. Especially if driverless (GOA4) signaling systems are preferred, these software become more important. In this study, the estimation of Vehicle Acceleration and Braking Acceleration with travel time has been carried out by using Machine Learning Methods. The ideal results obtained were given comparatively and interpreted on the graphics.

Improved AEB algorithm combined with estimating the adhesion coefficient of road ahead and considering the performance of EHB

This paper proposes an improved autonomous emergency braking (AEB) algorithm intended for intelligent vehicle. Featuring a combination with the estimation of road adhesion coefficient, the proposed approach takes into account the performance of electronic hydraulic brake. In order for the accurate yet fast estimate of road ahead adhesion coefficient, the expectation maximization framework is applied depending on the reflectivity of ground extracted by multiple beams lidar in four major steps, which are the rough extraction of ground points based on 3 σ criterion, the accurate extraction of ground points through principal component analysis (PCA), the main distribution characteristics of ground as extracted using the expectation maximum method (EM) and the estimation of road adhesion coefficient via joint probability. In order to describe the performance of EHB, the response characteristics, as well as the forward and adverse models of both braking pressure and acceleration are obtained. Then, with two typical roads including single homogeneous road and fragment pavement, the safe distance of improved AEB is modeled. To validate the algorithm developed in this paper, various tests have been conducted. According to the test results, the reflectivity of laser point cloud is effective in estimating the road adhesion coefficient. Moreover, considering the performance of EHB system, the improved AEB algorithm is deemed more consistent with the practicalities.

Повышение эффективности эксплуатации зимних шипованных шин

The aim of the study is to increase the efficiency of vehicle operation by establishing patterns of change in the performance properties of winter tires and improving, on this basis, methods for adjusting the frequency of their replacement. The research methodology is based on the application of a systematic approach, a number of private methods of the experimental-theoretical level and proven methods of processing experimental data. As a result of the analysis of key factors, the relevance of the application of repair technology for studding car tires has been substantiated. Experimental studies on measuring the braking distance and acceleration time have confirmed the need for prompt diagnostics of the residual number of studs on car tires. It was found that the efficiency of the tire as the actual number of studs decreases non-linearly and depends largely on the type of road surface used. The scientific novelty of the performed research is the regularities of braking and acceleration properties of cars operated on various road surfaces in winter conditions, taking into account the technical condition of studded tires. The practical significance of such stands is to increase the demand for this service by reducing costs and significantly reducing labor costs associated with assessing the performance of winter tires. Technological operations using portable stands can be combined with periodic maintenance or carried out with a seasonal tire change both at service stations and in motor transport companies. Further research is aimed at collecting, analyzing and systematizing data to establish the parameters of mathematical models of the most popular standard sizes of automobile winter tires, which will allow scaling the technology and reducing its cost due to mass use. Thus, the results of the on-line diagnostics of tires can be used by car owners when making timely decisions about replacement or repair, which significantly increases traffic safety and reduces the cost of operation, since if the integrity of the tread is preserved, the restoration of winter tires with repair studs almost completely restores the original properties that determine numerical values of efficiency indicators at significantly lower costs in comparison with buying a set of new tires.

Оцінка впливу режимів різання на вібрацію розточувального різця і точність оброблюваних отворів на верстатах з ЧПК

The accuracy of hole machining is significantly affected by factors such as vibrations that inevitably occur during the manufacturing of parts in the technological processing system (TPS). Among them, the vibration of the cutting tool is the most negative phenomenon, since it affects the accuracy and roughness of the treated surfaces, the performance of the machine and the service life of the cutting tool. Cantilever fixing of the cutting tool when boring holes reduces the rigidity of the TPS, which leads to a decrease in their accuracy. Currently, there are no systematic studies of the effect of the vibration stiffness of cantilever fixing tools on the accuracy of the resulting holes. Therefore, the study of the influence of vibrations of the boring cutter on the accuracy of hole processing on numerically controlled machines (CNC) is of great practical importance. When processing parts on modern CNC metal-cutting machines, their performance can be determined by the potentiometer indicators, which allows you to analyze the efficiency of the cutting process, its stability, the amplitude and magnitude of tool vibrations. The article analyzes the influence of vibrations of cutting tools that occur in the TPS during processing on the accuracy of boring holes, using the example of developing a technological route for mechanical processing of a part ‒ a floating pin designed to ensure the alignment of guides in the mold body, using the inventor 3D CAD-CAM system and the «Siemens NX» program. The problem was solved by boring precise holes with a diameter of 30H7 in 40X hardened steel workpieces using a «Sandvik-A20s-STFCR 11-RB1 CoroTurn 107» anti-vibration boring cutter equipped with a replaceable TCMT090204-UM carbide plate. The study was conducted at a modern CNC turning and milling center of the HAAS DS-30y model. Theoretically, it is shown that reducing the vibration of the boring cutter when boring a precise hole is achieved in the following cutting modes: depth t = 0,4 mm, feed s =0,1 mm/rpm and spindle speed n, which changes in the «acceleration‒braking» time interval of 2 seconds, that is, increases from n =1800 rpm to n =2000 rpm and, conversely, allows you to get a Æ30H7 hole with a cylindrical tolerance of up to 0,02 mm at a length of 100 mm.

Investigation of the dynamics of the manipulator drive with a stepper motor

A mathematical model of the manipulator drive with a stepper motor is developed in the form of inductance equations, which is a source of reactive moment, inertial moment equation and angular velocity. Stepper motors work in the drives of manipulators with continuous movement, when the control action is given by a sequence of electrical pulses. The block diagram of the speed and current control loop of the stepper motor, given by the operator, is calculated in the computer (full step, direction, correction value for reverse speed, acceleration braking), the data is sent to the controller, in the controller the signals pass through the hard logic circuits and are sent to the driver. The stepper motor driver board generates a signal that is fed to the stator windings of the stepper motor. The results of mathematical modeling in MATLAB & Simulink are presented. The dependences of the oscillatory process of the system in the transients of the stepper motor, which are oscillatory in nature, are obtained. A comparison of the results of theoretical modeling of the operation of a step drive with experimental studies is given. As a result of the simulation, additional dynamics arise in the armature current circuit, however, at the point of the nominal mode, it does not significantly affect the angular velocity regulation processes, that is, the speed regulator provides its astatic regulation under the action of a constant load moment.

Study on Theoretical Model and Test Method of Vertical Vibration of Elevator Traction System

In order to study the dynamic characteristics of the elevator, the response characteristics of the elevator under normal operation and emergency braking conditions are analyzed. In this paper, the centralized mass discretization model is used to study the vibration characteristics of the elevator traction system under the external excitation. Firstly, the vibration equation of the elevator multi-degrees-of-freedom (abbreviated as DOF) system is established. Then, the vibration characteristics of the three DOF system are analyzed, and the natural frequencies and modes are obtained. The free vibration equation and forced vibration equation are obtained, and the theoretical solutions are obtained. Finally, the test method proposed in this paper is used to test the normal operation and emergency braking of the elevator. The test results show that, under normal operation conditions, the measured speed and distance errors are not more than 4.2%, the up running distance measured by the elevator is larger than the actual value, while the down running distance is smaller than the actual value; under emergency braking condition, because the steel wire rope can only bear the pulling force, the peak acceleration fluctuation in the up emergency braking process is large, while the down emergency braking acceleration fluctuation is small. Therefore, the elevator vibration analysis model and the vibration test method proposed in this paper can be used for the analysis of elevator dynamic performance, which has great reference value for the safety performance research of the elevator traction system.

Displacement and acceleration feedback controller design for automated driving tram

Automated driving in train is discussing about partially implementation. Those implementations in limited area and situation marked well progress such as general railway lines and AGT. Tram vehicle on mixture traffic seems to be next target of them. Usual automated driving train is controlled considering with velocity and displacement as a position. However, tram vehicle run in the more complex situation than usual automated driving trains. Thus, there are much possibility braking to avoid collision with other traffic participants. In this time, the comfortability of passengers is decreasing if the huge braking acceleration occurring since acceleration is strongly relationship with it. Thus, Automated driving tram should be considered to control with acceleration to let acceleration smaller to improve passenger comfort. So, both displacement and acceleration feedback control are required. However, direct acceleration feedback should consider drift or noise on sensing results. This paper introduces direct acceleration feedback control with direct displacement control for positioning. These controllers are designed by Unified approach and Composite Filter. These controllers are considering with noise reduction for accelerometer. The example controller designed for small experimental rig on the rail are introduced with numerical simulation results. These results show the controllers can set desired poles related with settling time without considering of noise reduction frequency.

Simulation analysis of liquid sloshing under different working conditions of hazardous materials rescue truck

The geometric model is built with SOLIDWORKS, and the VOF(Volume Of Fluid) method in the CFD(Computational Fluid Dynamics) software fluent is used to simulate the sloshing characteristics during the brake and steering of the Hazardous Materials Rescue Truck. The braking acceleration, the liquid filling ratio of the vehicle, lateral acceleration, the effect of the baffle during braking and steering are respectively studied. The results show that the steering and braking of Hazardous Materials Rescue Trucks will cause the liquid in the tank to slosh, and the liquid sloshing will cause the wall slosh force of the tank to change. The driving stability of Hazardous Materials Rescue Trucks can be effectively improved by the reduction of braking force, proper liquid-filling ratio, reduction of lateral acceleration, and increase of baffles.

Numerical simulation of the influence of baffles on the impact force of heavy-duty tanker

The impact force of heavy-duty tanker is simulated and analyzed under liquid sloshing. Based on the finite volume method, the free liquid level capture technology (VOF) is used to establish a numerical calculation model for the sloshing analysis of heavy liquid tank trucks. FLUENT, a fluid simulation software, is used to simulate the impact of liquid on the front head of liquid tanker when the braking acceleration is 0.981m/s2, and the filling ratio is 0.5. The influence was studied that the number of rectangular baffles brings the changes of the impact force of the front head of the liquid tanker. The research provides a reference for the optimization design of baffles in heavy oil tanker manufacturers in the future and also validates the rationality of baffle set in the latest national standards.

Improvement on design and manufacture of bus based on traffic accident prevention

In some typical bus accidents, the causes of passenger injury have presented some common characteristics, which makes it necessary to improve the design of bus. In general, bus traffic accidents can be divided into two typical forms: emergency braking and rollover, both of which could seriously threaten the life security of passengers. In this article, these two kinds of bus accident are studied through numerical simulation and some improving suggestions on bus design and manufacture are given. According to simulation results, passengers may suffer from serious hurt due to emergency braking acceleration and deformation of bus body caused by the impact with highway guardrail. Improving measures include equipping seats with three-point belts, adding board on the handrail and enhancing the material and structure of side uprights of the bus. Simulation results show that these improving measures can provide better protection for the passengers involving bus traffic accidents, which has verified the rationality of these measures.

Cooperative collision avoidance algorithm for multi-vehicle based on vehicle networking technology

This paper addresses the problem of low success rate of traditional algorithm collision avoidance and poor control of parking distance. The vehicle network system and the vehicle kinematics model are established. The paper describes accurate estimation of the vehicle driving state in tunnel intranet based on vehicle sensor and vehicle GPS data. Constraints are established for fast response disturbances, rapid stabilisation, reduced braking acceleration and deceleration, and safe distances. From the energy point of view, we consider the relative kinetic energy of any two vehicles under the vehicle network, measure the collision risk, establish the objective function, and analyse the relative kinetic energy of all vehicles approaching the preceding vehicle. In this way, a multi-vehicle cooperative collision avoidance method based on vehicle network technology is realised. The experimental results show that the algorithm has strong collision avoidance performance, and the parking distance control is better, which can ensure safety.

Does Real-Time Feedback Make You Try Less Hard?: A Study of Automotive Telematics

Problem definition: Mobile and Internet-of-things (IoT) devices increasingly enable tracking of user behavior, and they often provide real-time or immediate feedback to consumers in an effort to improve their conduct. Growing adoption of such technologies leads to an important question: “Does immediate feedback provided to users improve their behavior?” We study immediate (close to real-time) feedback in the context of automotive telematics, which has been recognized as the most disruptive technology in the automotive insurance industry. Academic/Practical relevance: Numerous automotive telematics providers claim unsubstantiated benefits from immediate feedback, while we still barely understand the implications of such feedback on user behavior. Given that feedback’s effect sometimes is ambiguous, at the same time such feedback-providing devices’ usage is increasing, it is important to study immediate feedback and identify the effect it has on human behavior, especially in important applications, such as automotive. This understanding is important given that other attempts to make driving safer have led to unintended consequences in the past. Methodology: Using proprietary data on driving behavior, as measured by several parameters such as harsh braking, speeding, and steep acceleration, we investigate the impact of the driver’s decision to review immediate feedback on driving behavior. We use instrumental variable regression to estimate the effect. Results: Contrary to the claims from multiple telematics providers, we find that on average, users’ driving performance after they review detailed feedback is nearly 14.9% worse than that of users who do not review their detailed feedback. This impairment in performance translates to 6.9%, or a one-year reduction in inter-accident time. Our results suggest that this deterioration is associated with increased speeding. Strong negative feedback (e.g., a sharp deterioration in performance) exerts a positive effect on short-term performance but this only happens for very large drops in performance (3% of cases). Furthermore, we demonstrate that drivers just below the insurance incentive thresholds exert greater effort following immediate feedback. Managerial implications: Our results provide a key message to firms employing immediate feedback – specifically that such technology can yield unintended consequences. Furthermore, we show that drivers should receive only strong negative (but not positive) feedback to improve their performance. Finally, our results suggest that insurance incentives should be continuous, rather than a step function.

Studies on the dynamics of impact interaction of the mechanoreological model under elastic plastic transformation of its mechanical system

Dynamic interaction of machine and equipment parts and elements is a widespread process. Therefore, simulation and analysis of these processes are relevant tasks. To study impact interaction, a mechanorheological viscoelastic plastic model was developed. The force in the beginning of plastic deformations is an important model parameter. However, previous researches were carried out under impact loading of the model. They assumed that the plastic deformation occurs along with the elastic one. However, impact processes are more sophisticated. At first, only elastic deformations occur. When stresses achieve a yield point, plastic deformations occur. Therefore, the influence of the force on the model impact interaction dynamics is of great interest. The results let us draw the following conclusions. At the loading stage, when a viscoelastic model transforms into a viscoelastic plastic model, plastic deformations decrease the impact force and rebound height. Due to plastic deformations, the surface becomes more flexible, the impact duration increases body braking acceleration and inertia decrease. It leads to the decrease in the dynamic load and rebound height.The research results can be used for further development of methods for calculating model parameters, enhancing impact process simulation accuracy and reliability.