ESC System Map Data Integration for Yaw Rate Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Electronic Stability Control (ESC) systems lack awareness of road conditions and driver intentions, leading to suboptimal interventions during vehicle maneuvers, particularly on varying road geometries and surfaces.
Innovation Solution
The ESC system incorporates a digital map database to gather road property information, such as geometry, friction, and slope, which is used to adjust brake and throttle operations to enhance vehicle stability and reduce skidding, by comparing actual and intended yaw rates and modifying vehicle dynamics accordingly.
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 performs preliminary actions by obtaining road geometry information (curvature, slope, banking angle) from map data before the vehicle actually encounters those road conditions. This allows the ESC system to pre-calculate intended yaw rates and compare them with actual vehicle behavior, enabling proactive stability control rather than reactive correction after skidding begins.
Solution Approach 2:
Map data serves as an intermediary that bridges the gap between the ESC system and actual road conditions. Instead of directly sensing road geometry (which would require complex additional sensors), the system uses pre-stored map information about curvature, slope, and banking angle as a mediator to understand upcoming road conditions and adjust control parameters accordingly.
2Measurement precision
If ESC system applies aggressive brake intervention to correct yaw rate errors, then vehicle directional control improves, but driver feel and control authority deteriorate
Solution Approach 1:
The system applies partial action by using map data to determine the expected intended yaw rate, which represents only the portion of yaw rate correction that is actually necessary for maintaining stability on the given road geometry. This prevents excessive brake intervention that would occur with conventional systems trying to achieve zero yaw rate error, thereby maintaining driver control authority while still providing sufficient correction for safety.
Solution Approach 2:
The system changes the control parameter from raw yaw rate error to normalized yaw rate error by dividing by the map-based intended yaw rate. This parameter transformation allows the ESC system to distinguish between yaw rate deviations that are normal for the current road conditions (and should not be corrected) and those that indicate actual instability (requiring intervention).
3Speed
If ESC system uses only sensor-based feedback for stability control, then the response time is fast, but the anticipation of road conditions and driver intentions is lost
Solution Approach 1:
The system performs preliminary action by obtaining road geometry information from map data before the vehicle actually encounters those conditions. This allows the ESC to anticipate upcoming curves, slopes, and banking angles, and prepare appropriate control parameters in advance, rather than waiting for sensor feedback after instability begins.
Solution Approach 2:
The system implements feedback by continuously comparing the actual vehicle yaw rate with the map-based intended yaw rate. This closed-loop feedback mechanism uses the difference (normalized yaw rate error) to determine when and how much brake intervention is needed, combining the predictive power of map data with real-time vehicle state monitoring.
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 direction and/or yaw rate and an actual vehicle direction and/or 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 ESC 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.