Browse Topic: Brake pedals
The increasing pressure to decarbonize manufacturing systems is pushing industry beyond conventional lightweighting strategies toward material and process paradigms, capable of delivering functional performance with radically lower environmental impact. In this context, polymer-based composite Additive Manufacturing (AM) offers an underexplored yet highly promising pathway for sustainable production of load-bearing components. This study presents a preliminary comparative cradle-to-gate Life Cycle Assessment (LCA) of a Formula SAE brake pedal, assessing the environmental transition from conventional sheet metal fabrication and finishing operations of Aluminum 7075-T6 to additive manufacturing solutions, with specific focus on Carbon-Fiber-Reinforced Polymer (CFRP) composites. Two topology-optimized designs, respectively for Powder Bed Fusion (PBF) in AlSi10Mg and Material Extrusion (MEX) in Polyethylene Terephthalate Glycol with Carbon Fiber (PETG-CF) are compared to conventional fabrication aluminum benchmark. The analysis is integrated in the product and process design following ISO 14040/14044 standards and is implemented using the Environmental Footprint 3.0 methodology within the 3DEXPERIENCE platform. Results outline that Material Extrusion (MEX) composite manufacturing achieves the lowest environmental impact across all evaluated categories. Compared to conventional manufacturing, the PETG-CF solution enables an approximate 50% reduction in Global Warming Potential and an almost complete elimination of mineral depletion. Unlike metal additive manufacturing, which remains constrained by high process energy demand, MEX benefits from low processing temperatures, minimal auxiliary systems, and highly efficient material deposition. Crucially, these sustainability gains are achieved while maintaining functional performance through design-driven topology optimization. AM composite solutions, by merging advanced material science with additive flexibility, may lead to design approaches which cease to be ‘potential’ enablers of sustainable manufacturing for the Industry 5.0 transition.
As the adoption of electric vehicles continues to accelerate, the demand for their development and testing using chassis dynamometers has also increased significantly. Compared with internal combustion engine vehicles, chassis dynamometer testing for electric vehicles typically requires test durations several to several dozen times longer, resulting in substantially increased labor requirements. In addition, low-temperature testing is often required, further intensifying the workload associated with vehicle testing. To address these challenges, this study developed and evaluated a pedal robot designed to enable unmanned and automated testing. The pedal robot developed in this study weighs only 12 kg and can be installed within a few minutes. It is, to the authors’ knowledge, the world’s first pedal robot that mimics human driving behavior by using a single foot to operate both the accelerator and brake pedals. Unlike conventional driving robots, the actuators of the proposed system do not require direct mechanical attachment to the vehicle pedals, allowing for rapid installation. Furthermore, the robot is mounted on the driver-side floor, eliminating the need for attachment to the seat structure. The pedal robot features three degrees of freedom driven by three motors and employs artificial intelligence to recognize the shape and position of pedals across different vehicle models, thereby enabling automated test initiation without manual adjustment. The performance of the pedal robot was evaluated under UDDS, HWFET, and WLTC driving modes, and the results were analyzed in accordance with the SAE J2951 standard. Comparative evaluations demonstrated that the pedal robot achieved superior speed-tracking performance relative to that of an experienced human test driver. The developed pedal robot is currently being utilized for vehicle certification testing of electric and other vehicles at the Mobile Environment Research Center of the National Institute of Environmental Research in Korea. This paper presents a detailed analysis of the corresponding experimental results.
Indian passenger car accident data indicates that approximately 44% of crashes are frontal impacts (Refer fig 1). Among the injuries sustained in these crashes, lower leg injuries are notably critical, contributing to nearly 25% of driver occupant injuries (Refer fig 2). To evaluate such injuries, the Bharat New Car Assessment Program (BNCAP) includes lower leg injury metrics as part of the Frontal Offset Deformable Barrier (ODB64) test. While the overall injury performance is assessed at the vehicle level, BNCAP also monitors vehicle interior intrusions—particularly pedal intrusions—as key contributors to lower limb injury severity. A major challenge in frontal crashes is the intrusion of the vehicle's front-end structure into the occupant compartment. Rigid components, particularly the brake pedal assembly, can be displaced rearward during a crash, significantly increasing the risk of lower leg injuries. Therefore, minimizing pedal intrusions into the driver foot-well is critical for enhancing lower leg protection. As part of an innovative safety initiative, Tata Motors has developed a collapsible brake pedal mechanism designed to mitigate lower leg injuries during frontal crashes. This patented system incorporates a series of levers and linkages that disengage upon impact, allowing the brake pedal to collapse and thereby reducing the risk of intrusion-related injuries to the driver lower legs. The mechanism is engineered to be robust, ensuring that normal braking performance and pedal operation remain unaffected during everyday vehicle use, while providing effective injury mitigation in crash scenarios.
For mature virtual development, enlarging coverage of performances and driving conditions comparable with physical prototype is important. The subjective evaluation on various driving conditions to find abnormal or nonlinear phenomena as well as objective evaluation becomes indispensable even in virtual development stage. From the previous research, the road noise had been successfully predicted and replayed from the synthesis of system models. In this study, model based NVH simulator dedicated to virtual development have been implemented. At first, in addition to road noise, motor noise was predicted from experimental models such as blocked force and transfer function of motor, mount and body according to various vehicle conditions such as speed and torque. Next, to convert driver’s inputs such as acceleration and brake pedal, mode selection button and steering wheel to vehicle’s driving conditions, 1-D performance model was generated and calibrated. Finally, the audio and visual feedback correspondent with driver’s input was represented in the simulator with real-time data network between various hardware and software. To validate the simulator, subjective evaluation was performed with so-called virtual vehicles by changing tires, rubber mounts, suspension and body on various roads, speed and torque, which showed contextual results with physical prototypes. In conclusion, the NVH simulator equipped with consistent experimental and simulation models could be utilized to find and improve abnormal or nonlinear phenomena in virtual vehicle development stage, which can help to frontload vehicle development.
This SAE Recommend Practice specifies a method for measuring the deflection of friction materials and disc brake pad assemblies in a manner more consistent with classical material compressive strain testing. This SAE test method differs from SAE J2468 in the preload and maximum load applied to the test sample when deflection is measured. It adopts the material applied stress levels found in ISO 6310 (0.5 to 8.0 MPa) using a 25 mm diameter flat plunger.
This paper introduces a new systematic workflow for the rapid evaluation of energy-efficient automated driving controls in real vehicles in controlled laboratory conditions. This vehicle-in-the-loop (VIL) workflow, largely standardized and automated, is reusable and customizable, saves time and minimizes costly dynamometer time. In the first case study run with the VIL workflow, an automated car driven by an energy-efficient driving control previously developed at Argonne used up to 22 % less energy than a conventional control. In a VIL experiment, the real vehicle, positioned on a chassis dynamometer, has a digital twin that drives in a virtual world that replicates real-life situations, such as approaching a traffic signal or following other vehicles. The real and virtual systems interact in a close-loop fashion: the automated driving control directs accelerator and brake pedals based on measurements from the real vehicle and from the perception of the digital twin’s surrounding virtual environment; the resulting speed of the vehicle is fed back to the virtual world to compute the position of the digital twin. The VIL workflow provides a systematic linkage between the virtual environment, the hardware and software that interact with the vehicle and the dynamometer, as well as processes that facilitate scenario setup, code generation, experimentation, and data collection. Argonne’s RoadRunner, a simulation tool dedicated to the energy-focused study of connected and automated vehicles, serves as the virtual environment and is the backbone of the workflow. The real vehicle is tied to the chassis dynamometer, and a robotic driver actuates the accelerator and brake pedals based on the demands from the automated driving controls. During experimentation, the virtual environment, the data acquisition, the automated driving controls, as well as the low-level controls are run on a real-time system (dSPACE’s MicroAutoBox).
The braking capacity of reducing the speed or even keeping the vehicle stoped is extremely important in the design of any brake system, as more than meeting legislation requirements; it directly affects the safe operation of the vehicle and its users. A fundamental component, which requires notable attention, is the friction material, which is designed to establish a compromise between mechanical properties, friction coefficient, noise propensity, deformation, wear, among others. However, braking capacity is a combined response for several of these friction material properties, along with the performance of other brake system components, such as the brake chamber, disc and caliper. This work aims to analyze firstly the influence of the friction material deformation and secondly the brake system deformation on the total stroke of the brake chamber. To the first one, three different formulations of friction material, applied to commercial vehicles, were selected. For these materials, compressibility measurements were performed, according to ISO 6310, and also subjected to static test for measuring the total stroke of the brake chamber, in an inertial dynamometer. The static test performed consists of a pressure ramp application on the brake pad with the measurement of the total chamber stroke for each of the pressures. To the second one, static test was performed using steel pads (copying the brake pad shape), with thickness simulating new and end-of-life pads. The friction material and the brake system showed a significant pressure sensitivity, with a small contribution at low pressures, increasing its contribution with pressure increase. More than it, this work allowed to understand that the formulation, pad compressibility, material thickness, brake system stiffness, temperature and chamfered pads show a significant influence on the performance, fuel consumption and reduction of pollutants), there are also improvements to be made on braking performance and reduction of early wear. These improvements must also be applied to commercial vehicles such as trucks and buses, where the brake system is subjected to heavy loads and long routes. For this type of vehicle is very important to obtain maximum brake pad durability, in order to reach customer satisfaction. For commercial vehicles, the use of disc brakes has been increasing gradually, once it is already widely applied in Europe and there is a gradual growth in North American and Asian markets. Brazil tends to follow the same path as Europe, only slower, due to drum brakes costs, which are much lower than disc brake costs. Disc brake system has greater advantages compared to the drum brake system, such as: higher braking efficiency, even on higher application temperatures; greater dissipative energy capacity during braking and, finally, greater comfort during brake pedal actuation [2]. Pedal force and displacement are important factors for the driver to modulate, regarding safety and braking efficiency. It shows that soft pedal feeling is not only unsafe due to lack of vehicle control and accidental brake lock, but can also generate longer stopping distances [3]. Technically, the term known as Pedal Sensitivity means the relationship between the force applied to the pedal, the pedal travel and the deceleration achieved by the vehicle. Normally, the vehicle's brake capacity is evaluated on a field test, considering different conditions of deceleration, force and chamber stroke.
With the increasingly serious global environmental and energy problems, as well as the increasing number of vehicles, pure electric vehicles with its advantages of environmental protection, low noise and renewable energy, become an effective way to alleviate environmental pollution and energy crisis. Due to the current pure electric vehicle power battery technology is not perfect, the range of pure electric vehicle has a great limit. Through the braking energy recovery, the energy can be reused, the energy utilization rate can be improved, and the battery life of pure electric vehicles can be improved. In this paper, a pure electric vehicle is taken as the analysis object, and the whole vehicle analysis model is built. Through the comparative analysis, based on the driver's braking intention and vehicle running state, the braking energy recovery control strategy of double fuzzy control is proposed. The fuzzy controller of braking intention based on the brake pedal opening and the change rate of brake pedal opening and the fuzzy controller based on vehicle speed and battery SOC value are designed respectively, The braking energy recovery control strategy of pure electric vehicle is formulated. Using a variety of different conditions for simulation analysis, make it closer to the real driving conditions of pure electric vehicles1. The simulation results show that the braking energy recovery control strategy developed in this paper not only ensures the braking stability, but also performs better in terms of braking energy recovery efficiency. The braking energy recovery rate reaches 51%, and the effective energy recovery rate reaches 13%, which has a certain practical significance for improving the driving range of pure electric vehicles.
Being a safety critical aggregate, every aspect of brake system is considered significant in vehicles operations. Along with optimum performance of brake system in terms of deceleration generation, brake pedal feel or brake feel is considered as one of the key elements while evaluating brake system of vehicles. There are many factors such as liner and drum condition, road surface, friction between linkages which impress the pedal feel. Out of these, in this paper we will be discussing the factors which influence the brake pedal feel in relation to the driver comfort and confidence building. Under optimum braking condition, brake operation must be completed with pedal effort not very less or not very high, brake pedal feel must be firm throughout the operation, in such a way that it will not create fatigue and at the same time it will give enough confidence to the driver while operating with acceptable travel. These aspects are considered while evaluating the brake system performance in comparison with other competition vehicles. As results of these evaluations, mathematical model is built by considering brake pedal feel as dependent variable and factor influencing brake pedal feel as independent variables. Effects of most influencing variables on pedal feel are derived and compared with practical testing results to get optimum brake pedal feel.
SAE J1698-1A creates an appendix to SAE J1698-1. The appendix contains EDR Record parameters and definitions related to light duty passenger vehicle pedestrian protection systems.
The development of intelligent transportation improves road efficiency, reduces automobile energy consumption, and improves driving safety. The core of intelligent transportation is the two-way information interaction between vehicles and the road environment. At present, road environmental information can flow to the vehicle, while the vehicle’s information rarely flows to the outside world. The electronic throttle and electronic braking systems of some vehicles use sensors to get the state of the accelerator and brake pedal, which can be transmitted to the outside environment through technologies such as the Internet of Vehicles. But the Internet of Vehicles technology has not been widely used, and it relies on signal sources, which is a passive way of information acquisition. In this paper, an active identification method is proposed to get the vehicle pedal on-off state as well as the driver’s operation behavior through existing traffic facilities. The research object is the commercial vehicles driving on expressways. Vehicle speed is acquired by the camera, and specific vehicle models are identified by the camera to get the relevant vehicle parameters from the vehicle model database. Combined with road environment data, the pedal on-off state will be calculated by the vehicle dynamics model. The research results show that the judgment accuracy of the pedal opening and closing state is high, and the errors are generated at the time of the pedal opening and closing state transition, and the maximum error is 0.4 s. This study provides a new method for the outside access to vehicle longitudinal operation information in the intelligent transportation system and provides a backup scheme for the information interaction of the Internet of Vehicles, which can provide a reference for the determination of traffic accident liability.
In order to improve the driving experience of drivers and the efficiency of vehicle development, a method of objective drivability for passenger car powertrain is proposed, which is based on prior knowledge, principal component analysis (PCA) and SMART principle. First, drivability parameters of powertrain for passenger cars are determined according to working principle of powertrain, including engine torque, engine speed, gearbox position, accelerate pedal, brake pedal, steering wheel angle, longitudinal acceleration and lateral acceleration, etc. The drivability quantitative index system is designed based on field test data, prior knowledge and SMART principles. Then, D-S evidence theory and sliding window method are applied to identify objective drivability evaluation conditions of powertrain for passenger cars, including static gearshift conditions, starting conditions, creep conditions, tip-in, tip out, upshift conditions, acceleration, downshift conditions and de-acceleration. In addition, a quantitative index coupling analysis model is constructed by PCA, Kaiser-Meyer-Olkin (KMO) and correlation analysis are used to streamline the evaluation indicators by combining expert knowledge. Finally, fuzzy analytic hierarchy process (FAHP) is applied to build an objective index and subjective score mapping analysis model, and the tip-in condition is used as a case study to verify the reliability and accuracy of the objective evaluation model for the powertrain drivability proposed in this paper. This research can be used as a key reference for achieving the objective evaluation of passenger cars, including drivability, vehicle comfort and handling stability, and also provides a theoretical basis for the evaluation of drivability for new energy vehicles and autonomous vehicles.
Road traffic accidents resulting from alcohol-impaired driving are increasing globally despite several measures, currently in place, to curb the trend. For this reason, recent research aims at integrating alcohol early-detection systems and driving simulator experiments to identify intoxicated drivers. However, driving simulator experiments on drunk driving have focused mostly on male participants than female drivers whose characteristics have scarcely been explored. Hence in this paper, vehicle dynamic control inputs on steering, braking, and acceleration performance of 75 licensed female drivers with an upshot of alcohol at four different blood alcohol concentration (BAC) levels (0%, 0.03%, 0.05%, and 0.08%) were investigated. The participants completed simulated driving in a fixed-based simulator experiment coupled with real-time ecological scenarios to extract discrete responses. Vehicle dynamic characteristics data were obtained as signatures to alcohol detection based on the heterogeneous environmental settings, drivers’ state, and driver-vehicle control input variables. The results of the vehicle dynamics models showed that alcohol significantly impairs the driver steering control. For the 0.03, 0.05, and 0.08% BAC levels, mean acceleration values increased by 0.035, 0.045 and 0.053 m/s2, mean steered wheel angle of participants increased by 0.048, 0.082, and 0.160 degrees, and the increments according to the case of mean brake pedal force, were from 0.169N, 0.372N and 1.131N compared to baseline (0% BAC) state, respectively. Overall, the results revealed that drivers exerted excessive force on all control variables (steering, braking, and acceleration) which deteriorated their driving performance. The research outcome has the potential to deliver a benchmark countermeasure study and enhance stakeholders’ decisions against alcohol-impaired driving among female drivers.
A new type of electric brake booster, which can control brake pedal feeling completely with software, has been developed to explore how a brake system can be used to differentiate and personalize vehicles. In the future, vehicles may share an increasing amount of hardware and rely more heavily on software to differentiate between models. Car sharing, vehicle subscriptions, and other new business models may create a new emphasis on the personalization of vehicles that may be achieved most cost effectively by using software. This new brake booster controls the brake pedal force and brake pressure independently based on the brake pedal stroke so that the pedal feeling is completely defined by software. The booster uses two electric motors and one master cylinder. One electric motor controls the pedal force and provides an assist force that amplifies the force that the driver applies to the brake pedal. The second electric motor moves the master cylinder piston independently of the brake pedal stroke and is used to control the brake pressure. To confirm the real-world feasibility of this concept, the booster was installed in an actual vehicle. The evaluation of this vehicle confirmed that software-defined pedal feeling is feasible to implement in a real vehicle. Pedal feeling as good as that of a mass produced vehicle could be achieved, and the pedal feeling could be quickly and easily changed without the time and expense required to change brake hardware. Additionally, using this new booster, new types of pedal feeling that are not possible to achieve on a conventional vacuum booster vehicle could be easily implemented with software.
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