ESC System Using Map Data for Vehicle Stability
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Solution Overview
Problem
Conventional Electronic Stability Control (ESC) systems lack awareness of road conditions and driver intentions, leading to suboptimal interventions in maintaining vehicle stability, especially on varying road geometries and surfaces.
Innovation Solution
The ESC system integrates a digital map database to gather road property information, such as geometry, friction, and slope, which it uses to adjust brake and throttle operations to enhance vehicle stability and reduce yaw rate errors, thereby improving handling and preventing skidding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ESC systems operate without road condition awareness, then the system complexity remains low, but the vehicle stability control performance deteriorates on varying road geometries and surfaces
Solution Approach 1:
The system pre-acquires road geometry and surface property data from digital map databases before the vehicle encounters specific road conditions. This preliminary information is stored and ready for immediate use when the vehicle reaches relevant locations, enabling proactive adjustment of ESC parameters rather than reactive response to detected skidding
Solution Approach 2:
A digital map database serves as an intermediary between the vehicle's ESC system and the actual road conditions. The map database provides indirect information about road geometry, friction, and slope that the vehicle cannot directly sense, allowing the ESC system to anticipate and adapt to upcoming road conditions without direct measurement
2Measurement precision
If the ESC system uses basic sensor inputs only, then the device complexity remains low, but the intervention accuracy deteriorates due to lack of road condition context
Solution Approach 1:
The system continuously compares actual vehicle yaw rate and lateral acceleration with expected values derived from map data and driver input. This feedback loop allows the system to detect deviations caused by road conditions and adjust brake/throttle commands accordingly, improving measurement precision without adding complex sensors
Solution Approach 2:
The patent replaces direct mechanical sensing of road conditions with an information-based approach using digital maps and vehicle dynamics modeling. Instead of adding complex mechanical sensors to directly measure road friction or geometry, the system uses computational models that substitute physical measurement with information processing
3Ease of operation
If the ESC system intervenes conservatively to maintain driver control, then driver feel is preserved, but the effectiveness of skid reduction deteriorates on challenging road conditions
Solution Approach 1:
The ESC system dynamically adjusts its intervention strategy based on real-time conditions and map data. The control parameters such as brake force magnitude and application timing are not fixed but adapt according to road geometry, surface friction, and vehicle state, allowing the system to be more aggressive when needed while preserving driver control during normal operation
Data Source
AI summary
An Electronic Stability Control (ESC) system for a vehicle is disclosed. An electronic control unit (ECU) is programmed to reduce vehicle lateral skidding by reducing differences between an intended vehicle yaw rate and an actual vehicle yaw rate by applying modifications to operation of the vehicle brakes and/or throttle. The ESC system receives inputs from wheel speed sensors, a steering wheel position sensor, a yaw rate sensor and a lateral acceleration sensor. The ECS system also receives input that indicates at least a property of the road upon which the vehicle is located, wherein the road upon which the vehicle is located is determined from a positioning system that uses a map database and the property is determined from the map database. The ESC system incorporates the road property information in determining when and/or how to modify operation of the vehicle to reduce vehicle skidding.