Steering Control Apparatus Friction Transition-State Determination
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Solution Overview
Problem
Conventional steering control apparatuses require both steering-shaft and road-surface reaction torque detection, leading to space and man-hour challenges, as well as increased calculation loads, to accurately determine steering states and adjust hysteresis widths of steering torque.
Innovation Solution
A steering control apparatus that uses only steering-shaft reaction torque, employing a torque detection means, vehicle speed detection, and a friction transition-state determination method via integration of differential values with limiting functions to calculate assist correction values, eliminating the need for road-surface reaction torque detection and estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If road-surface reaction torque detection means is included to accurately determine steering state, then measurement precision is improved, but device complexity and mounting space increase
Solution Approach 1:
The patent extracts and eliminates the road-surface reaction torque detection means from the system, achieving accurate steering state determination using only steering-shaft reaction torque detection means. This resolves the contradiction by removing the complex detection device while maintaining measurement precision through alternative calculation methods.
Solution Approach 2:
The patent creates a virtual representation of road-surface reaction torque through calculation based on steering-shaft reaction torque data. Instead of directly measuring road-surface reaction torque, the system calculates equivalent values that replicate the information needed for steering state determination, thereby avoiding additional detection devices.
2Measurement precision
If road-surface reaction torque detection means is included to accurately determine steering state, then measurement precision is improved, but mounting time increases
Solution Approach 1:
The patent removes the road-surface reaction torque detection means from the system configuration, thereby eliminating the time-consuming mounting process while maintaining measurement precision through calculation-based approaches using only steering-shaft reaction torque data.
3Measurement precision
If road-surface reaction torque is used to determine steering state, then measurement precision is improved, but calculation load increases
Solution Approach 1:
The patent creates virtual road-surface reaction torque values through calculation based on steering-shaft reaction torque measurements. This approach replicates the necessary information for steering state determination without requiring direct road-surface reaction torque data, thereby reducing the calculation load on the estimator while maintaining measurement precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for accurate determination of friction transition-states without road-surface reaction torque, reducing installation space, man-hours, and calculation loads, while enabling stable adjustment of hysteresis widths of steering torque.
Implementation Method 1
the friction transition-state determination means determines a friction transition-state by integrating a differential value of the steering-shaft reaction torque using an integrator having a limiting function to an upper or lower limit value defined in advance
Data Source
AI summary
A steering control apparatus is obtained which includes an assist instruction-value correction device for calculating, based on a result of a friction transition-state determination device, an assist correction value in order to obtain an assist instruction-value after its correction being made by correcting a basic assist instruction-value so that a hysteresis width of steering torque increases at the time of turn-back steering, and an electric current driving device for driving a motor so that an electric current of the motor is coincident with an electric current instruction-value therefor after its correction being made on the basis of the assist instruction-value after its correction being made; and the friction transition-state determination device determines the friction transition-state by integrating a differential value of steering-shaft reaction torque using an integrator having a limiting function to an upper or lower limit value defined in advance.