Conceptual design evaluation of concurrent brake actuator mechanism

The proper amount of braking force on both wheels is needed to optimize the braking performance and stability of the motorcycle. The braking effectiveness can be maximized by keeping the ideal nonlinear brake force distribution during braking. Thus the purpose of this research is to present a mechanism that can be accommodated as a Concurrent Brake Actuator (CBA) design to control the ideal nonlinear brake force distribution. In this paper, the conceptual design of the CBA mechanism is developed to be used as a based design for CBA development. Thus, two conceptual designs of the CBA mechanism have been generated. The proposed concept designs were evaluated based on Design Failure Mode and Effect Analysis (DFMEA) and SOLIDWORKS Motion Analysis. The potential failure of the CBA concept design was determined based on the risk priority number (RPN) in DFMEA. The information obtained from DFMEA was used in SOLIDWORKS Motion Analysis to identify stress performance analysis for each CBA conceptual design. Then, the best CBA concept design will be selected. The selection was made based on the highest score gained by the CBA concept design in qualitative evaluation. Based on the results, the fixed main body design with a tilted position linear slope in CBA Design I is potentially to actuate and distribute the nonlinear brake force to the front and rear brake with less potential of failure. Therefore, the proposed mechanism design will be used as a based mechanism design for CBA development.

ON THE QUESTION OF BRAKING ARTICULATED BUSES

The safe movement of a car and a road train is largely determined by its braking properties. The nature of the movement of the road train is fundamentally different from the movement of a single car. The difference can be explained by the presence of additional forces arising in the articulation of the links of the vehicle, as well as forces and moments acting on its individual links and the movement of the vehicle as a whole. Their effect is especially noticeable when braking a road train, which may be accompanied by folding links and loss of stability of the vehicle. As a result of the study, the optimal values of the brake force distribution coefficients for a fully loaded articulated bus are obtained, which provide both high braking efficiency and the stability of the articulated bus (AВ) during braking. The coefficients are determined taking into account the design features of the brake mechanisms and their geometric dimensions, providing the required braking performance. For the selected values of the braking force distribution coefficients along the axes of the AВ and the coefficients that take into account the design features of the braking mechanisms and their geometric dimensions, the braking distance during braking by the main or working braking system and the spare one satisfy the requirements of regulatory documents. With the selected asynchronous response of the brake drives of the bus and trailer, the steady deceleration of the АВ is slightly less than the standard.

Calculation of brake-force distribution on three-axle agricultural trailers using simulation methods

The paper presents a new methodology for calculating the optimal linear distribution of braking forces for a three-axle trailer with "walking beam" and "bogie" suspension of the rear axle assembly that will meet the requirements of the new European legislation, EU Directive 2015/68. On this basis, a computer program for selecting the linear distribution of braking forces between axles has been developed. The presented calculations and simulation results of the braking process can be used in the design process to select the parameters of the wheel braking mechanisms and then the characteristics of the pneumatic valves of the braking system. The adaptation of the braking system of agriculture trailers is a very important factor for improving the safety of the transportation systems.

Sliding Mode Control of Vehicle Equipped with Brake-by-Wire System considering Braking Comfort

For passengers, the most common feeling during running on the bumpy road is continuous vertical discomfort, and when the vehicle is braking, especially the emergency braking, the instantaneous inertia of the vehicle can also cause a strong discomfort of the passengers, so studying the comfort of the vehicle during the braking process is of great significance for improving the performance of the vehicle. This paper presented a complete control scheme for vehicles equipped with the brake-by-wire (BBW) system aiming at ensuring braking comfort. A novel braking intention classification method was proposed based on vehicle braking comfort, which divided braking intention into mild brake, medium comfort brake, and emergency brake. Correspondingly, in order to improve the control accuracy of the vehicle brake system and to best meet the driver’s brake needs, a braking intention recognizer relying on fuzzy logic was established, which used the road condition and the brake pedal voltage and its change rate as input, output real-time driver's braking intention, and braking intensity. An optimal brake force distribution strategy for the vehicle equipped with the BBW system based on slip rate was proposed to determine the relationship between braking intensity and target slip ratio. Combined with the vehicle dynamics model, improved sliding mode controller, and brake force observer, the joint simulation was conducted in Simulink and CarSim. The cosimulation results show that the proposed braking intention classification method, braking intention recognizer, brake force distribution strategy, and sliding mode control can well ensure the braking comfort of the vehicle equipped with the BBW system under the premise of ensuring brake safety.

Analysis of cornering response and stability of electrified heavy commercial road vehicles with regenerative braking

Additional powertrain components and regenerative braking are two important factors that may affect the performance and stability of electrified vehicle cornering. The location of additional components affects the vehicle’s center of gravity (CG) position and thereby the stability of the vehicle. As regenerative braking is possible only on driven wheels, the brake force distribution between front and rear wheels may not follow the ideal brake force distribution curve. Hence, applying maximum regenerative braking during cornering may affect vehicle stability, and this has motivated the analysis presented in this paper. The scope of this research work includes obtaining a model for the regenerative brake system, which was then used to analyze the heavy commercial road vehicle lateral dynamic response during combined cornering and regenerative braking. A sensitivity study was carried out regarding variations in center of gravity, longitudinal speed, and tire–road traction coefficient [Formula: see text]. The IPG TruckMaker® vehicle simulation software running in a hardware-in-loop experimental system was used to study the heavy road vehicle cornering performance. The results showed that applying braking on a constant radius path required correction in the steering input to follow the desired path. However, the amount of steering correction required during regenerative braking was higher than that with conventional friction braking. Moreover, applying maximum regenerative braking at higher longitudinal speeds on snowy roads and split- µ roads has a higher impact on vehicle cornering performance compared with that on dry roads. Furthermore, a co-operative braking strategy with an optimum brake force sharing between regenerative braking and friction braking was developed to improve the electrified heavy commercial road vehicle’s cornering stability and handling performance during cornering and braking.

Dynamic Brake Force Distribution for Heavy Commercial Road Vehicles Using Wheel Slip Regulation

Wheel lock is an undesired phenomenon in Heavy Commercial Road Vehicles (HCRVs) and wheel slip control within a desired range is of crucial importance for stable and effective braking. This study proposes a framework to distribute brake force dynamically between the front and rear wheels, primarily to avoid instability by preventing wheel lock. Further, it ensures the maximum utilization of the available traction force at the tire-road interface that varies during the course of braking due to factors like load transfer. Wheel slip regulation provides an approach to maximize braking performance that subsumes the effects of varying road, load and braking conditions that occur during vehicle deceleration. The methodology proposed consists of a wheel slip controller that calculates the required brake force distribution parameters, which are then provided to the brake controller for control action. Sliding mode control was used because of the nonlinear nature of the longitudinal vehicle dynamic model considered and for robustness towards different parameter variations. The algorithm was implemented on a Hardware-in-Loop test setup consisting of a pneumatic air brake system, interfaced with IPG-TruckMaker® (a vehicle dynamic simulation software), and co-simulated with MATLAB-Simulink®. It was found that this algorithm improved the braking performance of a HCRV both in terms of stopping distance and vehicle stability.

Research on Instability Principle of Virtual Tracks Train When Braking on Curve

Virtual tracks train is a new type of rail transit, which combines traditional rail vehicles and road vehicles. In order to study the effect of braking on the stability of virtual tracks train on curve, a four-axle model with train body model, steering model, braking model and tire model was built in Matlab/Simulink to research the change of yaw velocity, lateral acceleration and vehicle speed when it brakes on curve. Through step steering test of the vehicle, the model was verified to analyze the braking stability on steady steering condition. Simulation result shows that when virtual tracks train brakes after 8s of turning with an individual axle locking up, different instability phenomena such as loss of guidance capacity, folding and drifting, would occur, which leads to instability of braking on curve. Using ABS can help improve the stability of it. With the instability principle put forward through the simulation, brake system and brake force distribution law could be designed to meet the need of virtual tracks train.

Design of brake force distribution model for front-and-rear-motor-drive electric vehicle based on radial basis function

To achieve high-efficiency and stable brake of a front-and-rear-motor-drive electric vehicle (FRMDEV) with parallel cooperative braking system, a multi-objective optimal model for brake force distribution is created based on radial basis function (RBF). First of all, the key factors, which are the coefficient of brake force distribution between the front and rear shafts, the coefficient of brake force distribution at wheels, the coefficient of regenerative brake force distribution between front and rear axles, that influence the brake stability and energy recovery of the FRMDEV are analyzed, the fitness functions of brake stability and energy recovery are established. Secondly, the maximum allowed regenerative brake torque influenced by the state of charge of battery is confirmed, the correction model of the optimal distribution coefficient of regenerative brake force is created according to motor temperatures. Thirdly, based on HALTON sequence method, a two-factor database, vehicle velocity and brake strength, that characterizes vehicle operation is designed. Then an off-line response database of the optimal brake force distribution is established with the use of particle swarm optimization (PSO). Furthermore, based on hybrid RBF, the function model of the factor database and the response database is established, and the accuracy of the model is analyzed. Specially, the correlation coefficient is 0.995 and the predictive error variance is within the range between 0.000155 and 0.00018. The both indicate that the multi-objective distribution model has high accuracy. Finally, a hardware-in-loop test platform is designed to verify the multi-objective optimal brake force distribution model. Test results show that the real-time performance of the model can meet the demand of engineering application. Meanwhile, it can achieve both the brake stability and energy recovery. In comparison with the original brake force distribution model based on the rule algorithm, the optimized one proposed in this paper is able to improve the energy, recovered into battery, by 14.75%.