Vehicle Power Steering Control Without Ground Speed Data
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Solution Overview
Problem
Recreational vehicles lack an active stability control system, and electronic power steering systems fail to function properly when ground speed data is faulty or unavailable, leading to steering offset biases due to calibration drift over time.
Innovation Solution
An electronic power steering system with a controller that detects engine speed, throttle valve opening, and gear selection to determine power steering assist levels, and includes a stability control system that adjusts vehicle systems based on terrain and sensor feedback to maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electronic power steering systems use ground speed data to determine steering torque assist, then steering assistance can be provided, but the system fails when ground speed data is faulty or unavailable
Solution Approach 1:
The patent introduces an intermediary variable (throttle valve opening) to replace the direct use of ground speed data. When ground speed data is unavailable or faulty, the controller uses throttle valve opening position as a substitute parameter to determine power steering assist level, thereby maintaining system functionality without direct dependence on ground speed sensors
Solution Approach 2:
The system dynamically changes the parameter used for control based on data availability. The controller switches between using ground speed data and throttle valve opening data depending on which is available and valid, allowing the power steering system to adapt to different operating conditions and sensor states
2Measurement precision
If power steering calibration is performed, then steering accuracy is improved, but calibration drift occurs over time causing steering offset bias
Solution Approach 1:
The system implements continuous feedback monitoring of steering sensor signals and compares them against expected ranges. When deviations indicating calibration drift are detected, the controller automatically compensates by adjusting the power steering assist calculation, thereby maintaining steering accuracy without requiring periodic manual recalibration
Solution Approach 2:
The power steering system performs self-correction of calibration drift through automatic detection and compensation mechanisms. The controller monitors steering sensor signals and autonomously adjusts assist levels to compensate for drift, eliminating the need for external intervention or manual recalibration procedures
3Device complexity
If recreational vehicles lack active stability control systems, then vehicle simplicity is maintained, but vehicle stability cannot be actively controlled
Solution Approach 1:
The controller integrates multiple functions into a single system, using the existing power steering controller to also perform stability control functions. By utilizing the throttle valve opening data and steering sensor signals already available for power steering operations, the system achieves both steering assistance and stability control without adding separate dedicated hardware systems
Solution Approach 2:
The patent merges power steering control and stability control into a unified system. The controller simultaneously processes steering requests and stability requirements, combining these functions into a single control algorithm that coordinates power delivery, steering assist, and stability management through integrated processing
Data Source
AI summary
A vehicle is provided including an electronic power steering system, an electronic throttle control system, and a stability control system.