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Open accessJournal ArticleDOI: 10.1088/1757-899X/263/6/062034

Braking distance algorithm for autonomous cars using road surface recognition

01 Nov 2017-Vol. 263, Iss: 6, pp 062034
Abstract: India is yet to accept semi/fully – autonomous cars and one of the reasons, was loss of control on bad roads. For a better handling on these roads we require advanced braking and that can be done by adapting electronics into the conventional type of braking. In Recent years, the automation in braking system led us to various benefits like traction control system, anti-lock braking system etc. This research work describes and experiments the method for recognizing road surface profile and calculating braking distance. An ultra-sonic surface recognition sensor, mounted underneath the car will send a high frequency wave on to the road surface, which is received by a receiver with in the sensor, it calculates the time taken for the wave to rebound and thus calculates the distance from the point where sensor is mounted. A displacement graph will be plotted based on the output of the sensor. A relationship can be derived between the displacement plot and roughness index through which the friction coefficient can be derived in Matlab for continuous calculation throughout the distance travelled. Since it is a non-contact type of profiling, it is non-destructive. The friction coefficient values received in real-time is used to calculate optimum braking distance. This system, when installed on normal cars can also be used to create a database of road surfaces, especially in cities, which can be shared with other cars. This will help in navigation as well as making the cars more efficient. more

Topics: Braking distance (64%), Traction control system (52%), Road surface (50%)

Open accessJournal ArticleDOI: 10.14498/TECH.2021.1.4
23 Apr 2021-
Abstract: The creation of robotic vehicles for agricultural purposes is a promising direction in the automotive industry. The complexity of the self-driving truck's design, work in difficult operating conditions, and a large number of measuring devices and processing subsystems determine the relevance of creating a virtual test system. These tests are part of the overall virtual commissioning process for a robotic vehicle. The article discusses a set of basic subsystems that provide virtual tests based on a model-based approach: mathematical modeling, measurement modeling, information subsystem with databases, visualization and documentation subsystem. Metrological models of measuring channels for virtual tests have been developed, allowing simulating random vehicle parameter changes. The testing process covers all the most essential components of a robotic vehicle. For example, the article presents a dynamic model of the braking system of a robotic chassis and shows the results of braking modes' virtual tests. The developed virtual test system is used to create a KAMAZ truck as part of a robotic system for agricultural vehicles. more

Topics: Chassis (53%)

Journal ArticleDOI: 10.1076/VESD.
Abstract: Summary A control scheme for emergency braking of vehicles is designed. The tire/road friction is described by a LuGre dynamic friction model. The control system output is the pressure in the master cylinder of the brake system. The controller utilizes estimated states for a feedback control law that achieves a near maximum deceleration. The state observer is designed using linear matrix inequality (LMI) techniques. The analysis shows that using the wheel angular speed information exclusively is not sufficient to rapidly estimate the velocity and relative velocity, due to the fact that the dynamical system is almost unobservable with this measurement as output. Findings are confirmed by simulation results that show that the estimated vehicle velocity and relative velocity converge slowly to their true values, even though the internal friction state and friction parameters converge quickly. The proposed control system has two main advantages when compared with an antilock braking system (ABS): (1) it produ... more

Topics: Anti-lock braking system (61%), State observer (56%), Control theory (54%) more

99 Citations

Journal ArticleDOI: 10.1109/19.310171
David Webster1Institutions (1)
Abstract: A pulsed ultrasonic distance measurement system (UDMS) for use in air is described. A new method of timing is presented that is based upon the transmission of a binary-frequency shift-keyed (BFSK) signal followed by data acquisition and signal processing of phase-digitized information from the received signal. The method reduces many of the problems that arise when dealing with the nonideal behavior of ultrasonic transducers. One of the major advantages is the ease with which the method may be implemented while maintaining high accuracy, since amplitude sampling is not required. Comparison with common ranging techniques is presented, which shows the inherent noise immunity of the new method. A test setup is described, and results given, demonstrating the underlying principle and accuracy. The system measures distances of up to 5000 mm with an accuracy of /spl plusmn/1 mm. > more

Topics: Ultrasonic sensor (57%), Signal (55%), Sampling (signal processing) (54%) more

68 Citations

Journal ArticleDOI: 10.1016/J.ARCONTROL.2016.04.005
B. Ashok1, S. Denis Ashok1, C. Ramesh Kumar1Institutions (1)
Abstract: Engine management systems (EMS) has become an essential component of a spark ignition (SI) engine in order to achieve high performance; low fuel consumption and low exhaust emissions An engine management system (EMS) is a mixed-signal embedded system interacting with the engine through number of sensors and actuators In addition, it includes an engine control algorithm in the control unit The control strategies in EMS are intended for air-to-fuel ratio control, ignition control, electronic throttle control, idle speed control, etc Hence, the control system architecture of an EMS consists of many sub-control modules in its structural design to provide an effective output from the engine Superior output from the engine is attained by the effective design and implementation of the control system in EMS The design of an engine control system is a very challenging task because of the complexity of the functions involved This paper consolidates an overview of the vital developments within the SI engine control system strategies and reviews about some of the basic control modules in the engine management system more

Topics: Engine control unit (70%), Electronic throttle control (61%), Control system (54%) more

50 Citations

Open accessJournal Article
Abstract: Stopping sight distance is an important design parameter in that it defines the minimum sight distance that must be provided at all points along the highway. Thus, it influences geometric design values, construction costs, and highway safety. Stopping sight distance is defined as the sum of two components - brake reaction distance and the braking distance. The basic model for calculating stopping sight distances was formalized in 1940, and the model's parameters have been altered to compensate for changes in eye height, object height, and driver behavior over the past 50 years. Recent studies, however, question whether the model's parameters and assumptions represent real-world conditions. This paper presents a new model for determining stopping sight distance requirements for geometric design of highways. The new model is based on parameters describing driver and vehicle capabilities that can be validated with field data and defended as safe driving behavior. More than 50 drivers, 3,000 braking maneuvers, 1,000 driver eye heights, and 1,000 accident narratives were used in developing the recommended parameter values for the new model. The recommended values are attainable by most drivers, vehicles, and roadways. The new model results in stopping sight distances, sag vertical curve lengths, and lateral clearances that are between the current minimum and desirable requirements, and crest vertical curve lengths that are shorter than current minimum requirements. more

Topics: Stopping sight distance (77%), Braking distance (59%), Geometric design (51%) more

33 Citations

Journal ArticleDOI: 10.1076/VESD.
Abstract: In this paper, we propose a new control strategy for an antilock braking system (ABS) to maintain the braking force at maximum. The popularization of the ABS that prevents the wheels from locking has resulted in an improvement of the vehicle stability and shortening of the braking distance. Further improvement is anticipated if the maximization of the braking force is realized. We found an interesting phenomenon in which the characteristics of the resonance system composed of the vehicle body and the wheel and road surface reflects the slip condition of the road surface. Using this phenomenon, we realized a control method for maintaining the maximum value of the braking force. more

30 Citations

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