This paper analyses ESP/ESC in vehicles.
Electronic stability control (=ESC) as active safety system is getting more and more common in todays vehicles. First established in 1995 by Bosch and Daimler under the well known brand ESP it has obviously prevented many accidents all around the world. Many studies show that the main target of ESC which is preventing fatal side crashes into the less resistant side components of vehicles was reached. It shows that average skilled drivers are just not able to perform the necessary measures to escape riskful lateral driving conditions on their own.
This evidence and the fact that ESC is rather cheap to implement into an existing vehicle structure due to the usage of Antilock-System (=ABS) and Anti Slip Control (=ASC) hardware components led to the fact that many states passed laws which makes an ESC system mandatory in every vehicle sold in their territory. ESC is based on fundamental control engineering, vehicle dynamics, fluidmechanics as well as the combination of different energy domains (electric, mechanic, hydraulic) and is using the vehicle brakes as well as reducing engine power to stabilize vehicle behaviour in critical driving situations like over- and understeering. These circumstances can be measured, predicted and processed by several sensors and the control unit itself in order to initiate the appropriate actor reactions. Parameters that are necessary for the control algorithm but are hardly measurable with sensors like the effective friction coeffient between road and tire need to be calculated via other auxiliary variables e.g. rotational speeds.
Since ESC is always in it’s overall component structure the same but in its specific reaction (=control) and modeling differing due to the desired driving behaviour of a particular manufacturer, tests need to be performed to prove the stabilizing effectiveness of its output signals which are represented as brake torques and reduction of engine power. In order to perform these tests engineers need to understand the systems general behaviour (=transfer function) which makes it then possible to design different test scenarios stimulating the system, determining crucial measurement variables and analyzing their results. There are many tests concerning vehicle stability established in the industry already. These verifications can be virtually and/or physically conducted.
Table of Contents
- 1. ESP® - A spreading brand
- 2. ESC System operation
- 2.1 Mechanical Background
- 2.2 Operation conditions
- 2.3 Control loop
- 3. ESC system testing
- 3.1 Challenges and chances on vehicle dynamics testing
- 3.2 ECE Reg. 140 ESC test standardization
Objectives and Key Themes
This paper aims to explain the functionality of Electronic Stability Control (ESC) systems and the challenges involved in testing their effectiveness. The paper explores the system's operation, focusing on its mechanical background, operating conditions, and control loop. It also discusses the complexities of testing ESC systems, both virtually and physically, including the standardized ECE Reg. 140 test procedure.
- The functionality and importance of Electronic Stability Control (ESC) systems in enhancing vehicle safety.
- The mechanical principles and vehicle dynamics underlying ESC system operation.
- The various operating conditions and driving maneuvers that necessitate ESC intervention.
- The challenges and opportunities presented by both physical and virtual testing methods for ESC systems.
- The standardized ECE Reg. 140 test procedure for ESC system verification.
Chapter Summaries
1. ESP® - A spreading brand: This chapter introduces Electronic Stability Control (ESC), clarifying its relationship to the trademarked name ESP®. It highlights the widespread adoption of ESC as a mandatory safety feature in many regions, driven by studies demonstrating its significant effectiveness in reducing accidents. The chapter emphasizes the variability in ESC system implementation across different vehicle manufacturers, leading to the necessity for rigorous testing to ensure effectiveness.
2. ESC System operation: This chapter delves into the operational mechanics of ESC systems. It begins by explaining the crucial role of vehicle dynamics, particularly lateral dynamics and tire forces, in understanding ESC's functionality. The concept of the Kamm's circle is introduced to illustrate tire force limitations and the conditions leading to under- and oversteering. The chapter then describes the operating conditions that trigger ESC activation, differentiating between under- and oversteering scenarios and explaining how the system intervenes using individual wheel braking and engine power reduction to maintain vehicle stability. Finally, the chapter details the control loop of the ESC system, outlining its sensors, actuators, and control algorithms employed to achieve the desired vehicle behavior.
3. ESC system testing: This chapter explores the challenges and opportunities in testing ESC systems. It emphasizes the influence of environmental factors and driver behavior on vehicle dynamics, highlighting the limitations of purely physical testing. The chapter then introduces virtual testing methods, particularly the Hardware-in-the-Loop (HIL) simulation approach, as a cost-effective and efficient way to overcome these limitations and optimize ESC system performance. Finally, the chapter details the standardized ECE Reg. 140 test procedure, outlining its requirements and the parameters used to ensure consistent and comparable results across different vehicle models.
Keywords
Electronic Stability Control (ESC), Active Safety Systems, Vehicle Safety, Vehicle Dynamics, System Testing, Under-steering, Over-steering, Kamm's Circle, ECE Reg. 140, Hardware-in-the-Loop (HIL) Simulation, Anti-lock Braking System (ABS), Anti-Slip Control (ASC).
Electronic Stability Control (ESC) System: A Comprehensive Overview - FAQ
What is the main topic of this document?
This document provides a comprehensive overview of Electronic Stability Control (ESC) systems, covering their functionality, operation, testing methodologies, and key components. It also explores the standardized testing procedures used to verify their effectiveness.
What are the key objectives of this paper?
The paper aims to explain the functionality of Electronic Stability Control (ESC) systems and the challenges involved in testing their effectiveness. It explores the system's operation, focusing on its mechanical background, operating conditions, and control loop. It also discusses the complexities of testing ESC systems, including the standardized ECE Reg. 140 test procedure.
What are the main themes discussed in the document?
The key themes include the functionality and importance of ESC systems, the mechanical principles and vehicle dynamics underlying their operation, the operating conditions triggering ESC intervention, the challenges and opportunities of physical and virtual testing methods, and the standardized ECE Reg. 140 test procedure.
What is Electronic Stability Control (ESC)?
Electronic Stability Control (ESC), also known by the trademark name ESP®, is an active safety system designed to enhance vehicle stability and prevent loss of control. It works by detecting and correcting skids or spins through selective braking of individual wheels and/or engine power reduction.
How does an ESC system operate?
An ESC system operates by monitoring various vehicle parameters (e.g., steering angle, wheel speed, yaw rate). When it detects a deviation from the intended path, it intervenes by selectively braking individual wheels and/or reducing engine power to restore stability. The system's operation is heavily reliant on an understanding of vehicle dynamics, specifically lateral dynamics and tire forces.
What are the key components and processes within the ESC control loop?
The ESC control loop comprises sensors (measuring vehicle parameters), a control unit (processing data and calculating corrective actions), and actuators (applying braking forces and controlling engine power). The control algorithms within the unit determine the appropriate intervention strategy based on the detected vehicle state.
What are the challenges in testing ESC systems?
Testing ESC systems presents significant challenges. Environmental factors and driver behavior greatly influence vehicle dynamics, making purely physical testing limited. Virtual testing methods like Hardware-in-the-Loop (HIL) simulation are employed to overcome these limitations, allowing for controlled testing and optimization.
What is ECE Reg. 140?
ECE Reg. 140 is a standardized test procedure for ESC systems that ensures consistent and comparable results across different vehicle models. It outlines specific requirements and parameters for testing, enabling independent verification of ESC system effectiveness.
What are the different operating conditions that might necessitate ESC intervention?
ESC intervention is triggered by various conditions, primarily those involving a loss of vehicle stability. These include understeer (the vehicle fails to turn as sharply as the driver intends) and oversteer (the rear of the vehicle slides out). Different operating conditions and driving maneuvers can lead to these situations.
What are the key terms and concepts related to ESC systems?
Key terms include Electronic Stability Control (ESC), Active Safety Systems, Vehicle Dynamics, System Testing, Understeer, Oversteer, Kamm's Circle (illustrating tire force limits), ECE Reg. 140, Hardware-in-the-Loop (HIL) Simulation, Anti-lock Braking System (ABS), and Anti-Slip Control (ASC).
- Quote paper
- Carlo Baunach (Author), 2018, Testing of ESP/ESC in vehicles. A wholistic approach to the complex, Munich, GRIN Verlag, https://www.hausarbeiten.de/document/461412
