Braking Torque Research Articles

CONTROL SYSTEM OF THE ELECTRIC DRIVE OF THE LOOP HOLDER OF THE FINISHING GROUP OF THE HOT ROLLING MILL, WHICH IMPLEMENTS CONTROL AND FORCING OF THE ELECTRIC DRIVE MOMENT

The operation of the DC electric drive of the loop holder installed on the hot rolling mill between the stands of the finishing group, which is part of the SARN with the indirect principle of metal tension control, which generates control signals based on the control of the specific tension of the strip passing between two stands, is considered. It is shown that the SARN action algorithm is based on taking into account the impact on the strip of the auxiliary mechanism – the loop holder, the frame of which must be rotated to the optimal angle. The conditions are described under which the looper is in an equilibrium state, when the moment of the electric motor balances the moment of resistance on its shaft, determined by the force arising due to the tension of the strip. It is shown that the high-speed electric drive of the looper, which is in the steady braking mode for most of the cycle time and creates a braking torque, at the moment the strip enters the interstand gap, should provide a short-term forcing of the moment for the movement of the frame, followed by a stop in the allowable zone of the angle of rotation.

Modelling and simulation of automatic brake system of vehicle

The increasing rate of road accidents is alarming and any vehicle that does not have an effective braking system is vulnerable to an accident with human and property consequences. This is due to human error when driving, involving reaction time delays and loss of concentration. An automatic braking system is an active safety system equipped on modern cars to minimize the possibility of a collision while participating in traffic. The automatic braking system helps warn the driver of an impending collision and helps the driver brake with maximum force or automatically brake the car in an emergency situation. This study analyzes the working principle of the automatic braking system, designs an obstacle detection model using ultrasonic sensors, and models an automatic braking system using the rules in the controller. Fuzzy logic for the system for anti-lock braking detection and model simulation has been developed using Matlab - Simulink software to achieve high braking torque, optimum slip ratio, distance, and stopping time in shorter car. The results show that the distance and stopping time are improved compared to when the controller is not used.

Instantaneous optimum wheel slip estimation of anti-lock braking system based on extremum seeking algorithm and fuzzy method

The anti-lock braking system (ABS) adjusts the longitudinal wheel slip at its optimum value to achieve the maximum braking forces. The highest braking force capacity happens at a specific slip value and depends on the friction coefficient between the tire and the road, vertical tire force, and vehicle speed. Hence, using a fixed value for the desired longitudinal slip is not appropriate. To solve this problem, the instantaneous optimum wheel slip is determined via the sliding mode-based extremum seeking algorithm in combination with the fuzzy method to achieve the maximum possible brake deceleration. Then the nonlinear prediction-based controller is designed to find the braking torque by adjusting the longitudinal slip in the calculated desired value. In addition, a nonlinear half-vehicle model considering pitch dynamics is developed and validated with the Carsim software. The main contribution of the present work involves the combination of the optimal nonlinear predictive control method with the fuzzy extremum seeking algorithm to design a wheel slip controller. Additionally, the pitch dynamics has been taken into account in the design of the control system. The performance of the designed control system is investigated through conducted simulations in Matlab/Simulink software environment. The obtained results show an enhancement in the braking performance along with a considerable reduction in the stopping distance.

Biodiesel with Fuel Additive: An Analysis of Engine Performance, Combustion and Emission Characteristics

Threats to the environment from exhaust emissions and global warming continue to generate more calls by most governments to end the use of fossil fuels and switch to green fuels. This study aims to examine one of the green fuels that is seeing rapid expansion, namely the biofuel known as biodiesel. Biodiesel is non-toxic, biodegradable, made from renewable sources and can reduce diesel engine exhaust emissions. Even though one of the technical benefits of biodiesel is its ability to be oxygenated in diesel engines without much hardware modifications; however, it has been unable to reduce exhaust tail emissions from diesel engines on its own. In this research, the impact of biodiesel mixed with oxygenated additive, diethyl ether, when subjected to performance, combustion, and emission tests in unmodified diesel engine at different speeds has been studied. Waste cooking oil was transesterified using methanol as a reagent and NaOH as catalyst. The biodiesel was blended manually at room temperature with diesel fuel and diethyl ether in different proportions while keeping the volume of diethyl ether constant at 10 %. The fuel blends (B10D90, B20D80, B30D70, B10A10D80, B20A10D70, and B30A10D60) were subjected to performance, combustion, and emission tests in a single-cylinder, four-stroke diesel engine coupled to a water-cooled Eddy current dynamometer and results obtained compared with diesel fuel. The results showed that all performance characteristics (brake power (BP), brake torque (BT), brake thermal efficiency (BTE) and brake specific fuel consumption (BSFC)) improved with B10A10, which was found to closely resemble diesel. The peak cylinder pressures were higher for the blends, while the cylinder temperatures were comparable to those of diesel. The carbon monoxide (CO), carbon dioxide (CO2), hydrocarbon (HC) and oxides of nitrogen (NOx) emissions decreased more for all tested blends than for those of diesel at all engine speeds. Adding diethyl ether additives improved the physicochemical properties of biodiesel, making it a viable method for using biodiesel efficiently in diesel engines without modifying the engine. The study found that using green diesel fuel with a diethyl ether additive is a potential step toward improving air quality by lowering emissions from stationary, and transportation engines while maintaining optimal engine performance. As a result, using biodiesel-diesel fuels with the appropriate proportions of diethyl either additive has the potential to reduce greenhouse gas (GHG) emissions and ensure benign environment.

The Recovering Stability of a Towing Taxi-Out System from a Lateral Instability with Differential Braking Perspective: Modeling and Simulation

The traditional method of taxiing for civil aircraft, which relies on their engines, may be surpassed by the new method of towing taxi-out due to its superior advantages such as reduced energy consumption, lower emissions, and higher efficiency. However, the towing taxi-out system poses a challenge to lateral stability due to the concentration of mass at the rear, leading to severe instability when turning at high speeds. To address this issue, a nonlinear civil aircraft towing and taxiing system model and a linear four-degree-of-freedom civil aircraft towing and taxiing system reference model were established using TruckSim and Matlab/Simulink software. The fuzzy proportional–integral–derivative controller was utilized, with the braking torque of each wheel serving as the control variable and the real-time yaw rate difference and its rate of change as the fuzzy control input. The controller was compared and validated with a traditional PID controller. The results of the simulation showed that the fuzzy PID control has better nonlinear characteristics and stronger adaptability to operating conditions compared to traditional PID control, providing timely, effective, adaptive, and robust control effects for the vehicle dynamics model. Under the fuzzy PID control, the peak yaw speed of the civil aircraft decreased to 10 degrees per second under double-shift conditions, representing an increase of 23.1%. Furthermore, the lateral stability and safety of the towing taxi-out system were improved, as evidenced by the reduction in the yaw rate of the tractor and civil aircraft under the hook condition. The use of this controller provides valuable technical guidance and support for the practical development and safe application of the towed glide mode.

Hopf-curve-based torque distribution strategy for avoiding limit cycle vibration in hybrid braking system model

Limit cycle vibration affects ride comfort and safety of electric vehicle. In the present study, a Hopf curve was proposed for development of brake torque distribution strategy to circumvent limit cycle vibration. The stability and bifurcation conditions were evaluated based on brake-driveline coupling model of the hybrid braking system. The limit cycle vibration was predicted through the boundary between stable and unstable equilibrium regions. The findings showed that the limit cycle vibration was circumvented by tuning the hydraulic braking force based on the Hopf curve. The insufficient braking torque caused by the decrease in hydraulic braking force was compensated by the driven motor. The findings of the present study provide information on the passive suppression of limit cycle vibration in hybrid braking system to improve the comfort of electric vehicles.

Study on the characteristics of an electromagnetic damping generator

This paper proposes an electromagnetic damping generator (EDG), which is a novel downhole generator for the rotary steerable system (RSS). The EDG is designed to solve the problem of unstable voltage output by the RSS generator. The generator is designed by integrating a traditional generator and an eddy current retarder (ECR). The system converts the excess kinetic energy of the EDG rotor into heating energy by the principle of eddy-current braking and resistance heating. The electromagnetic finite element models of the generator part and ECR part are established and solved by computer. The voltage and torque generated by the generator part and the braking torque of the ECR part are predicted. In the bench test, When the input power is 2537 W < Pinput < 3304 W, the EDG is able to output 300.8 V. When the input power is 3304 W, the output voltage of the ordinary generator is 346 V. The EDG can be adjusted by a decrement of up to 45.2 V to output the rated voltage. The problem of generator output voltage instability in the RSS is solved when mud flow is unstable.

A μ‐H∞ control strategy for decreasing torque fluctuation of electro‐hydraulic integrated braking system in mode switching

AbstractDue to the difference of time‐domain response between hydraulic braking and regenerative braking, as well as changes of equivalent parameters and operating parameters during braking mode switching, it is liable to cause torque fluctuation, which affects braking safety and vehicle ride comfort. First, the uncertainties of vehicle load and frictional coefficient model are investigated. Second, the hybrid system theory is applied to provide state transfer condition for mode switching strategy. Finally, the control strategy that utilizes regenerative braking torque to compensate for difference of the required braking torque is designed, and a new μ‐H∞ control algorithm through D‐K iteration is presented to improve the robust performance. The proposed μ‐H∞ control strategy is examined under various braking situations, and the results indicate that (1) the μ‐H∞ controller have the advantage of robustness performance, the amplitude of regenerative braking is decreased by 6.14%, and the steady‐state error of hydraulic braking is decreased by 5.26% over the H∞, and (2) under the braking mode switching, the designed compensation control strategy has the performance of fast and accurate tracking of the desired torque, and the steady‐state error does not exceed 3.5%.

Apparent dispersion in pulsar braking index measurements caused by timing noise

ABSTRACT Stochastic temporal wandering of the spin frequency ν of a rotation-powered pulsar (i.e. the achromatic component of timing noise unrelated to interstellar propagation) affects the accuracy with which the secular braking torque can be measured. Observational studies confirm that pulsars with anomalous braking indices $\vert n \vert = \vert \nu \ddot{\nu } / \dot{\nu }^2 \vert \gg 1$ exhibit elevated levels of timing noise, where an overdot symbolizes a derivative with respect to time. Here it is shown, through analytic calculations and Monte Carlo simulations involving synthetic data and modern Bayesian timing techniques, that the variance 〈n2〉 of the measured n scales with the square of the timing noise amplitude $\sigma _{\ddot{\nu }}$ . The anomalous regime 〈n2〉 ≫ 1 corresponds to $\sigma _{\ddot{\nu }}^2 \gg 10^{-60} (\gamma _{\ddot{\nu }}/10^{-6} \, {\rm s^{-1}})^2 (\dot{\nu } / 10^{-14} \, {\rm Hz \, s^{-1}})^4 (\nu / 1 \, {\rm Hz})^{-2} (T_{\rm obs} / 10^8 \, {\rm s}) \, {\rm Hz}^2{\rm s}^{-5 }$ , where $\gamma _{\ddot{\nu }}$ is a stellar damping time-scale, and Tobs is the total observing time. When the inequality in the earlier condition is reversed, n is dominated by the secular braking torque, and timing measurements return n ∼ 3, if the secular braking torque is electromagnetic. The variance 〈n2〉 is greater, when the stochastic process driving spin fluctuations differs from the red noise model (e.g. power-law spectral density) assumed in the timing solution.

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.

Constraints on Magnetic Braking from the G8 Dwarf Stars 61 UMa and τ Cet

During the first half of their main-sequence lifetimes, stars rapidly lose angular momentum to their magnetized winds, a process known as magnetic braking. Recent observations suggest a substantial decrease in the magnetic braking efficiency when stars reach a critical value of the Rossby number, the stellar rotation period normalized by the convective overturn timescale. Cooler stars have deeper convection zones with longer overturn times, reaching this critical Rossby number at slower rotation rates. The nature and timing of the transition to weakened magnetic braking have previously been constrained by several solar analogs and two slightly hotter stars. In this Letter, we derive the first direct constraints from stars cooler than the Sun. We present new spectropolarimetry of the old G8 dwarf τ Cet from the Large Binocular Telescope, and we reanalyze a published Zeeman Doppler image of the younger G8 star 61 UMa, yielding the large-scale magnetic field strengths and morphologies. We estimate mass-loss rates using archival X-ray observations and inferences from Lyα measurements, and we adopt other stellar properties from asteroseismology and spectral energy distribution fitting. The resulting calculations of the wind braking torque demonstrate that the rate of angular momentum loss drops by a factor of 300 between the ages of these two stars (1.4–9 Gyr), well above theoretical expectations. We summarize the available data to help constrain the value of the critical Rossby number, and we identify a new signature of the long-period detection edge in recent measurements from the Kepler mission.

“Evaluation of an electromagnetically actuated drum brake concept”

In publications and conferences on the subject of wheel brakes, different concepts of electromechanically actuated wheel brakes can be found, as well as investigations into their suitability for the use in passenger cars. The vast majority of these brakes are disc or drum brakes, which are actuated by an electric motor. In the present publication, a brake concept is considered, that combines an electromagnetically actuated full-pad disc brake with a 10″ duo-duplex drum brake. The brake concept is researched in a project regarding brakes for autonomous shuttles and thus dimensioned using vehicle data of an example shuttle. The electromagnet was designed using finite element methods and the overall brake prototypically realized. The validation of the system design is carried out in component and system tests. The results show the suitability of the concept for the selected vehicle in terms of dynamics, installation space and energy requirements. However, there is a strong dependence of the braking torque output on the frictional sliding speed. Using hypothesis-based testing, electromagnetic effects like eddy currents are ruled out as a possible cause and the friction coefficient within the full-pad disc brake is identified as the main cause for the loss in torque. Consequently, the associated development conflict is identified and lies in the double function of the flux-carrying material in the electromagnet, which also acts as a friction partner for the braking disc.

Calculation of no‐load induced electromotive force of pole changing line‐start permanent magnet synchronous motor

AbstractPole changing line‐start permanent magnet synchronous motor (LSPMSM) can significantly improve the starting capability of LSPMSM by decreasing the braking torque and pulsating torque during starting process. The fundamental reason for the elimination of braking torque is that there is no generating effect during minor‐pole starting process. That is to say, induced electromotive force (EMF) does not exist when the magnetic field generated by multi‐pole rotor PMs cut the minor‐pole stator winding. Therefore, the induced EMF of pole changing LSPMSM is analysed theoretically and calculated analytically. Considering that the magnetic flux per pole of the coils under the adjacent pole are different, the induced EMFs of a conductor, a full‐pitch coil, a coil group in minor‐pole stator winding are, respectively, calculated, and then the general analytical expression of the induced EMF of a phase winding with different rotor/stator pole ratio is derived. Then, the motors with different rotor/stator pole ratios are simulated based on finite element method to obtain the corresponding EMFs. Meanwhile, a 6/8 pole changing LSPMSM is taken as prototype. The consistency of the simulation, experiment, and the analytical calculation results effectively verify the validity of the derived general analytical expression and theoretical analysis.

A basic study on braking and regenerative braking torques for an axial gap type eddy current brake

Because of growing demand in the aircraft industry, research is being conducted around the world to reduce CO2 emissions by electrifying aircraft. The authors are studying a non-contact hybrid aircraft brake that combines an eddy current brake and a magnetorheological fluid brake. This paper presents a basic study of braking and regenerative torque using an axial gap type eddy current brake. The result as that a maximum braking torque of 51.3 mNm was obtained with a three-phase AC power supply when the speed of the conductor disc was 2,000 rpm, the current was 3 A, and the frequency was 10 Hz in the CW direction. The maximum regenerative torque was 48 mNm when the speed of the conductor disc was 2,000 rpm, the current was 3 A, and the frequency was 10 Hz in the CCW direction.

Regenerative braking torque compensation control based on improved ADRC

Electro-hydraulic braking (EHB) compensation is an effective method to solve the insufficient regenerative braking of electric vehicles, but the accuracy and speed of executive pressure response are still insufficient. In order to solve this problem, a brake pressure compensation control method based on EHB system is proposed and verified. Firstly, adaptive LuGre friction model and braking dead time compensation are introduced to obtain a more accurate friction model. Then, an electro-hydraulic braking control strategy based on Improved Active Disturbance Rejection Control (IADRC) is proposed. Finally, the effectiveness of the proposed method is verified by simulation experiments and hardware-in-the-loop (HIL) simulation experiments. The test results show that the proposed control method can achieve accurate control of brake pressure compensation in time. The research results promote the research and application of EHB system to a certain extent.

ПОВЫШЕНИЕ БЕЗОПАСНОСТИ АВТОТРАНСПОРТНЫХ СРЕДСТВ И РЕСУРСОСБЕРЕЖЕНИЕ ПРИ ИСПОЛЬЗОВАНИИ ДВИГАТЕЛЯ ВНУТРЕННЕГО СГОРАНИЯ В КАЧЕСТВЕ ТОРМОЗА-ЗАМЕДЛИТЕЛЯ

The article analyzes the mechanical losses in the internal combustion engine that create the braking torque of the engine, examines the parameters that affect its value. It is shown that during planned braking, the use of an internal combustion engine as a retarder brake does not lead to negative consequences, both for the engine itself and for all transmission elements, and timely switching of the gearbox to a reduced gear keeps the deceleration of the car at the highest possible level, as a result, the service life of the brake pads increases and fuel consumption decreases.

Research on Adaptive Distribution Control Strategy of Braking Force for Pure Electric Vehicles

The actual driving conditions of electric vehicles (EVs) are complex and changeable. Limited by road adhesion conditions, it is necessary to give priority to ensuring safety, taking into account the energy recovery ratio of the vehicle during braking to obtain better braking quality. In this work, an electric vehicle with an EHB (electro-hydraulic braking) system whose braking force adaptive distribution control strategy is studied. Firstly, the vehicle dynamics model, including seven degrees of freedom, tire, drive motor, main reducer, battery pack, and braking system, was constructed, which is attributed to the vehicle configuration and braking system scheme. Second, based on curve I and ECE regulations, the adaptive braking force distribution control strategy was formulated by taking the maximum regenerative braking torque as the inflection point, the synchronous adhesion coefficient as the desired point, and the battery SOC, road adhesion coefficient, and braking strength as the threshold. Finally, the vehicle dynamics simulation model was built on the Matlab/Simulink platform, and the simulation results verified the feasibility of the proposed braking force adaptive allocation control strategy. The research shows that the adaptive distribution control strategy can better adapt to the complex and variable driving conditions of the vehicle by combining the inflection point and the desired point. The braking energy recovery ratios of the vehicle under the NEDC and NYCC cycle conditions on a high adhesion road are 52.62% and 47.45%. The braking force distribution curve is close to curve I under the low adhesion extreme road.

Accurate and Simple Modeling of Eddy Current Braking Torque: Analysis and Experimental Validation

A compact, reliable and straightforward mathematical modeling of the eddy current braking torque is proposed in this paper. First, the braking magnetic force, which curbs the movement of a rotating disk (RD) is evaluated using the basic laws of electromagnetism. Second, the braking torque is related to the braking force through a polynomial function model. The model parameters are evaluated by plugging in measurement samples in the equation of motion taking into account the nonlinear behaviour of the aerodynamic drag forces. The proposed model neither has limitations on the braking system geometry nor the disk rotational speed as long as measurement samples cover whole speed range. Moreover, it is validated experimentally for constant and alternating magnetic flux profiles with best fit rates (BFRs) more than 85% and 93% for both rotational velocity and braking torque, respectively. Furthermore, programmable braking application is demonstrated using the proposed approach and its applicability is verified experimentally.

Calculation of the output parameters of a drum brake mechanism with floating blocks

A technique is developed for calculating the output indicators of a drum brake mechanism (BM) with floating blocks based on the BM scheme, dimensional parameters of the components, friction coefficient in the contact areas of the linings and drive forces of the blocks. The technique allows at the design stage to determine the design parameters of the BM, their effect on the braking torque, the effectiveness of the blocks, the support reactions of the blocks and the maximum pressure on the friction linings. Examples of calculations of BM with one leading block and with servo amplification are given. Keywords: brake system, drum brake mechanism, floating block, braking effectiveness. harbatsenka.m@yandex.ru

Theoretical investigation of braking of tearing mode rotation by resistive walls in ITER

The locking of the 2/1 tearing mode to the resistive wall in the ITER tokamak (15 MA inductive scenario 2) is investigated theoretically using a cylindrical asymptotic matching model. The model takes into account the fact that ITER plasmas will effectively be surrounded by two walls; the inner blanket module layer with a time constant of about 23 ms, and the outer vacuum vessel with a time constant of about 380 ms. The model also takes cognizance of the fact that neither the blanket module layer nor the vacuum vessel can be accurately described as “thin” walls (in the ordinarily accepted sense). The model incorporates changes in both the plasma poloidal and the toroidal angular velocity profiles, in response to the electromagnetic braking torque that develops at the rational surface, because it turns out that neoclassical poloidal flow-damping is not strong enough to completely suppress changes in the poloidal velocity. Finally, the model accurately calculates changes in the poloidal and toroidal plasma angular velocity profiles by evolving the full angular equations of motion, taking the electromagnetic braking torque, plasma inertia, plasma viscosity, and poloidal flow-damping into account. The time required for the 2/1 tearing mode to grow from a small amplitude to a sufficient one to lock to the walls is found to be about 3.5 s. The critical full radial island width at which wall locking is triggered is found to be about 9% of the plasma minor radius.