EPS Steering Torque Adjustment for Understeering Detection
Solution Overview
Problem
Existing vehicles equipped with electric power steering (EPS) and anti-lock braking system (ABS) lack an effective method to detect understeering without additional sensors or actuators, making it difficult to provide timely assistance to drivers in emergency situations, especially since systems like ESP are costly and complex to install.
Innovation Solution
A method that uses the onboard computer of the EPS to estimate the theoretical angular position of the steering wheel based on wheel speed information from the ABS, comparing it to the real angular position to calculate the understeering ratio, allowing for modification of the steering torque to assist the driver without additional sensors or actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ESP system is installed to detect and counter understeering, then vehicle stability is improved, but device complexity and cost increase significantly
Solution Approach 1:
The patent makes the EPS system multi-functional by enabling it to perform both its original steering assistance function and the additional function of detecting understeering conditions. The EPS computer analyzes wheel speed data from ABS and steering wheel position data to calculate understeering ratio, allowing one system to serve multiple purposes without adding dedicated ESP hardware.
Solution Approach 2:
The patent combines the understeering detection functionality with the existing EPS system. Instead of implementing a separate ESP system with dedicated sensors and actuators, the invention merges the detection and control functions into the EPS computer, which already processes steering-related data and controls the electric motor.
2Measurement precision
If additional sensors and actuators are added for understeering detection, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent applies self-service by having the EPS system use data already being collected by existing vehicle systems. The EPS computer utilizes wheel speed information from the ABS system and steering wheel position information from its own sensors to calculate understeering ratio, eliminating the need for additional dedicated sensors while maintaining detection capability.
Solution Approach 2:
The invention makes existing sensors multi-functional. The wheel speed sensors originally designed for ABS functionality are also used for understeering detection, and the steering wheel position sensor serves both steering control and stability analysis purposes, maximizing the utility of existing hardware.
Data Source
AI summary
The invention relates to a method for calculating the understeering ratio of automobiles provided with electric power steering (EPS) including an electric assistance motor (9) driven by an onboard electronic computer (11), a sensor (12, 14) providing a first piece of information on a real angular position of the steering wheel (3), a wheel anti-lock braking system (ABS) providing a second piece of information on the speed of the wheels (15) of the vehicle, characterised in that the onboard computer (11) of the EPS processes the second piece of information for estimating a theoretical angular position of the steering wheel (3), which is further compared to the real angular position of the steering wheel (3) in order to derive the understeering ratio (τ) of the vehicle.