Steering Control Apparatus Dynamic Gain Arbitration
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Solution Overview
Problem
Conventional vehicular steering control systems experience time delays when switching control modes, leading to improper timing of force application for the steering wheel, which can result in unnatural sensations for the driver and compromised vehicle control.
Innovation Solution
A steering control apparatus with operation control means that includes first and second controlled variable inputs, gain calculation, and arbitration mechanisms to quickly adjust and prioritize forces applied to the steering wheel, ensuring timely and smooth mode switching without interfering with each other.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If gradual reduction of yaw-rate-reaction-force target current and gradual increase of lane-keeping-assist target current are implemented during mode switching, then unnatural steering sensation is prevented, but control response timing is delayed
Solution Approach 1:
The patent applies dynamics by making the gain variable rather than fixed. The gain changes based on the magnitude of the first controlled variable, allowing the system to adapt its switching behavior dynamically. When the first controlled variable is small, the gain is large enabling quick switching; when the first controlled variable is large, the gain is small preventing unnatural sensations.
Solution Approach 2:
The patent changes the parameter of gain magnitude based on the controlled variable magnitude. By adjusting the gain parameter dynamically according to the first controlled variable's magnitude, the system achieves both quick response when needed and smooth transitions when the controlled variable is small, resolving the time delay issue.
2Stability of the object's composition
If maximum value of change in controlled variable is restricted during control switching, then shock is mitigated, but control switching speed is reduced
Solution Approach 1:
The patent makes the gain dynamic rather than fixed, allowing it to adjust based on the first controlled variable's magnitude. This dynamic adjustment enables the system to switch control modes quickly when the controlled variable is large while maintaining stability when it is small, resolving the contradiction between switching speed and stability.
Solution Approach 2:
The patent changes the gain parameter based on the magnitude of the first controlled variable. This parameter change strategy allows the system to achieve both fast switching and stable control by adapting the gain to the current operating conditions, specifically allowing larger changes when the controlled variable is large and smaller changes when it is small.
Data Source
AI summary
A coordinate-control-gain calculation section 61 calculates a coordinate-control final control torque T_C required to properly control the traveling behavior of a vehicle, and determines a coordinate control gain Kg on the basis of the magnitude of this torque T_C. An arbitration-request determination section 62 determines the value of an arbitration request flag FRG_A on the basis of the magnitude of the torque T_C and the value of a flag FRG_L output so as to properly control the traveling behavior of a vehicle. On the basis of the value of the flag FRG_A and the magnitude of the coordinate-control arbitration torque Tr determined by use of the gain Kg, an arbitration section 63 selects the torque T_C or the torque Tr to be output as a post-arbitration control torque T_F. A post-arbitration drive control section 64 supplies to an electric motor a drive current corresponding to the determined torque T_F.