Antilock Braking System Using Dynamic Speed Estimation

2015 ◽  
Vol 72 (2) ◽  
Author(s):  
Fargham Sandhu ◽  
Hazlina Selamat ◽  
Yahaya Md Sam
Keyword(s):  
Characteristic Function ◽  
Wheel Speed ◽  
Dominant Factor ◽  
The Road ◽  
Antilock Braking System ◽  
Switching Functions ◽  
Road Friction ◽  
Braking Distance ◽  
Antilock Braking ◽  
Proper Estimation

Antilock braking systems use slip to control braking, for which the velocity of the car and wheel speeds of the wheels are required. The wheel speeds can be measured directly but the velocity of the vehicle is difficult to measure. Although the wheel speed can be used to calculate the linear velocity of the vehicle using the tire characteristic function, it depends upon various environmental and time varying parameters. The dominant factor in the characteristic function is the road friction coefficient. Due to the difficulties in proper estimation of the road friction, most systems calculate the optimal values offline and apply them at different speeds using switching functions. By using the tire model and the optimal friction coefficients, the velocity of the vehicle is estimated and used for calculating the optimal braking force, resulting in inappropriate control of braking creating longer braking distances. In the method proposed in this paper, an estimator will be used to estimate the velocity, which is proved to be more accurate than calculated from the wheel speeds. The estimated velocity and the pitch angle will be used to schedule the braking forces in order to reduce the braking time. The braking time of the proposed system lies between the ideal braking time and the conventional reference wheel speed related braking time, indicating an improvement in reducing the braking distance.   

An Adaptive and Fast Control Strategy for Antilock Braking System

2015 ◽  
Author(s):  
S. Tajeddin ◽  
M. Batra ◽  
N. L. Azad ◽  
J. McPhee ◽  
R. A. Fraser
Keyword(s):  
Passenger Cars ◽  
The Road ◽  
Braking System ◽  
Antilock Braking System ◽  
New Strategy ◽  
Road Friction ◽  
Antilock Braking ◽  
And Performance ◽  
Road Characteristics ◽  
Abs Algorithm

After more than 30 years since the Antilock Braking System (ABS) was first introduced, it has become the most important active safety system used on passenger cars. However, it is hard to find a precise description of ABS, its stability and performance in the literature. Most of ABS algorithms currently used are not adaptive to changes of road friction conditions. The aim of our work is to provide a new ABS algorithm that is adaptive to changes of road conditions. To this end, an online parameter estimator is designed to estimate the road characteristics and maximum possible deceleration. Then, a driver demand regulator is proposed to limit the demanded deceleration to the maximum values. In this new strategy, road characteristics are estimated prior to the braking, not during the braking which makes it fast and adaptive. The proposed ABS algorithm is simulated on an artificial driving track and simulation results have been compared to a simple non-adaptive 6-phase Bosch ABS algorithm as our benchmark that is based on deceleration thresholds. Results show a better braking performance and more than 30% of reduction in braking distance.

Application of microwave Doppler displacement sensors in anti-lock braking system

2021 ◽  
pp. 43-48
Author(s):  
Dmitry V. Khablov
Keyword(s):  
Distribution System ◽  
Wheel Speed ◽  
Road Surface ◽  
The Road ◽  
Braking System ◽  
Speed Sensor ◽  
Displacement Sensors ◽  
Braking Distance ◽  
Braking Force

The issues of optimization of the vehicle anti-lock braking system are considered. To increase the reliability of the system, it is proposed to use a brake distribution system adaptive to the quality of the road surface for a quick stop of the vehicle while maintaining controllability. The system together with sensors angular wheel speed included a microwave Doppler displacement and speed sensor. The use of the specified Doppler sensor made it possible to achieve a more accurate coincidence of the dependence of the braking force on the degree of adhesion of the wheels to the road surface by monitoring the ratio between the angular and linear speeds of movement. In this way, it was possible to minimize the braking distance of the vehicle while maintaining controllability under various driving conditions.

scholarly journals Estimation of the Tire Contact Patch Length and Normal Load Using Intelligent Tires and Its Application in Small Ground Robot to Estimate the Tire-Road Friction

2016 ◽  
Vol 44 (4) ◽  
pp. 248-261 ◽  
Author(s):  
Seyedmeysam Khaleghian ◽  
Omid Ghasemalizadeh ◽  
Saied Taheri
Keyword(s):  
Normal Load ◽  
Accurate Estimation ◽  
Contact Patch ◽  
The Road ◽  
Antilock Braking System ◽  
Road Friction ◽  
Friction Estimation ◽  
Flexible Strain Sensor ◽  
Tire Forces ◽  
Patch Length

ABSTRACT Tire-road friction estimation is one of the most popular problems for the tire and vehicle industry. Accurate estimation of the tire-road friction leads to better performance of the traction and antilock braking system controllers, which reduces the number of accidents. Several researchers have worked in the field of friction estimation, and many tire models have been developed to predict the tire-road friction. In this article, an intelligent tire, which has an embedded accelerometer placed on the inner liner of the tire, is used to estimate the tire contact patch length parameter and normal load. To accomplish this, first, an existing tire testing trailer equipped with a force hub to measure tire forces and moments, a high-accuracy encoder to measure the angular velocity of the wheel, and VBOX, which is a global positioning system–based device, to estimate the longitudinal speed of the trailer was used. As a practical application for the normal load algorithm, a wheeled ground robot, which is equipped with several sensors, including an accelerometer and a flexible strain sensor inside the tire (used for terrain identification purposes), was designed and built. A set of algorithms was developed and used with the test data that were collected with both the trailer and the robot, and the contact patch length and the normal load were estimated. Also, the friction potential between the tire and the road was evaluated using a small ground robot.

Slip-Based Tire-Road Friction Estimation During Braking

2001 ◽  
Author(s):  
Steffen Müller ◽  
Michael Uchanski ◽  
Karl Hedrick
Keyword(s):  
Pressure Sensor ◽  
Slip Line ◽  
Traction Force ◽  
Field Tests ◽  
Wheel Speed ◽  
The Road ◽  
Brake Pressure ◽  
Road Friction ◽  
Friction Estimation ◽  
Using Data

Abstract We develop a slip-based method that estimates tire-road friction during braking using data from standard ABS wheel speed sensors and a brake pressure sensor. During a braking maneuver, normalized traction force, μ, vs. slip data is collected and the slope of this μ vs. slip line is used to estimate the road friction. Results from field tests of the algorithm are presented.

scholarly journals Design, Analysis and Application of Single-Wheel Test Bench for All-Electric Antilock Braking System in Electric Vehicles

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1294
Author(s):  
Xiangdang XUE ◽  
Ka Wai Eric CHENG ◽  
Wing Wa CHAN ◽  
Yat Chi FONG ◽  
Kin Lung Jerry KAN ◽  
...  
Keyword(s):  
Electric Vehicles ◽  
Test Bench ◽  
Potential Candidate ◽  
Vertical Force ◽  
Abs Algorithms ◽  
Braking System ◽  
Vehicle Velocity ◽  
Antilock Braking System ◽  
Antilock Braking ◽  
Electromechanical Brake

An antilock braking system (ABS) is one of the most important components in a road vehicle, which provides active protection during braking, to prevent the wheels from locking-up and achieve handling stability and steerability. The all-electric ABS without any hydraulic components is a potential candidate for electric vehicles. To demonstrate and examine the all-electric ABS algorithms, this article proposes a single-wheel all-electric ABS test bench, which mainly includes the vehicle wheel, the roller, the flywheels, and the electromechanical brake. To simulate dynamic operation of a real vehicle’s wheel, the kinetic energy of the total rotary components in the bench is designed to match the quarter of the one of a commercial car. The vertical force to the wheel is adjustable. The tire-roller contact simulates the real tire-road contact. The roller’s circumferential velocity represents the longitudinal vehicle velocity. The design and analysis of the proposed bench are described in detail. For the developed prototype, the rated clamping force of the electromechanical brake is 11 kN, the maximum vertical force to the wheel reaches 300 kg, and the maximum roller (vehicle) velocity reaches 100 km/h. The measurable bandwidth of the wheel speed is 4 Hz–2 kHz and the motor speed is 2.5 Hz–50 kHz. The measured results including the roller (vehicle) velocity, the wheel velocity, and the wheel slip are satisfactory. This article offers the effective tools to verify all-electric ABS algorithms in a laboratory, hence saving time and cost for the subsequent test on a real road.

Anti-Lock Wheel Slip Control With an Adaptive Searching Algorithm for the Optimal Slip

2015 ◽  
Author(s):  
Ning Pan ◽  
Liangyao Yu ◽  
Lei Zhang ◽  
Zhizhong Wang ◽  
Jian Song
Keyword(s):  
Lyapunov Theory ◽  
Modulation Amplitude ◽  
Wheel Slip ◽  
Slip Control ◽  
The Road ◽  
Road Friction ◽  
Speed Fluctuation ◽  
On The Road ◽  
Pressure Modulation ◽  
Abs Algorithm

An adaptive searching algorithm for the optimal slip during ABS wheel slip control is proposed. By taking advantage of the fluctuation of wheel slip control, the direction towards the optimal slip can be found, and the target slip calculated by the algorithm asymptotically converged to the optimal slip, which is proved using the Lyapunov theory. A gain-scheduling wheel slip controller is developed to control the wheel slip to the target slip. Simulations on the uniform road and on the road with changed friction are carried out to verify the effectiveness of the proposed algorithm. Simulation results show that the ABS algorithm using the proposed searching algorithm can make full use of the road friction and adapts to road friction changes. Comparing with the conventional rule-based ABS, the pressure modulation amplitude and wheel speed fluctuation is significantly reduced, improving control performance of ABS.

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