Steering Control Apparatus Road Surface Allocation
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Solution Overview
Problem
Existing steering control systems, such as steer-by-wire and electric power steering systems, face challenges in fine-tuning steering feel due to the lack of controlled steering angle and incorporation of road surface information, making it difficult to adjust the reaction force applied to the steering wheel effectively.
Innovation Solution
A steering control apparatus that includes a reaction force processing unit with a steering angle control processing unit, ideal-component calculation unit, road surface component calculation unit, and allocated component calculation unit, which allocates road surface information to adjust the target steering angle, allowing for precise control and fine-tuning of steering feel by incorporating road surface information into the reaction force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control is used to adjust reaction force current to target value, then reaction force control is achieved, but steering angle remains uncontrolled making fine-tuning of steering feel difficult
Solution Approach 1:
The reaction force is segmented into two distinct components: an ideal component (not incorporating road surface information) and a road surface component (incorporating road surface information). These components are calculated separately and then allocated in a predetermined ratio to form the target reaction force. This segmentation allows independent control of each component, enabling precise steering angle control while maintaining system manageability.
Solution Approach 2:
The system dynamically changes the allocation ratio parameter between the ideal component and road surface component based on driving conditions. By adjusting this ratio parameter, the control system can fine-tune the steering feel to match different road surfaces and driving scenarios without requiring complete redesign of the control architecture.
2Loss of information
If road surface information is incorporated in reaction force, then steering feel information is improved, but steering angle control and fine-tuning capability are lost
Solution Approach 1:
The reaction force is divided into an ideal component that provides baseline steering characteristics and a road surface component that incorporates road surface information. By segmenting the reaction force this way, the system preserves steering angle controllability through the ideal component while simultaneously transmitting road surface information through the road surface component.
Solution Approach 2:
The allocation ratio between the ideal component and road surface component is made dynamic rather than fixed. The control system can adjust this ratio in real-time based on driving conditions, road surface types, and driver preferences, enabling easy fine-tuning of steering feel while maintaining continuous road surface information transmission.
3Reliability
If mechanical connection between steering wheel and steered wheels is maintained, then natural reaction force is provided, but responsiveness and control precision are reduced
Solution Approach 1:
The patent replaces the traditional mechanical connection between steering wheel and steered wheels with a reaction force actuator that applies electromagnetic force. This substitution eliminates mechanical friction and inertia delays, significantly improving steering response speed and control precision while maintaining system reliability through electronic control and feedback mechanisms.
Solution Approach 2:
The system implements feedback control by continuously monitoring the actual reaction force and steering angle, comparing them with target values, and adjusting the actuator output accordingly. This feedback mechanism ensures reliable and accurate steering control despite the removal of direct mechanical connection, maintaining system reliability through active electronic control.
Data Source
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AI summary
A steering control apparatus includes a steering angle feedback processing unit M22 and an operation signal generation processing unit M24 that operate a reaction force actuator to adjust a steering angle θh to a target steering angle θh* that is a target value for the steering angle θh based on feedback control, an ideal-axial-force calculation unit M10ab that calculates an ideal axial force Fib, a road-surface-axial-force calculation unit M10ac that calculates a road surface axial force Fer, an axial-force allocation calculation unit M10aa that calculates a base reaction force Fd in which the ideal axial force Fib and the road surface axial force Fer are allocated in a predetermined ratio, and a target steering angle calculation processing unit M20 that sets a target steering angle θh* based on the base reaction force Fd. The steering angle feedback processing unit M22 feeds back the target steering angle θh* in which road surface information is incorporated through the road surface axial force Fer, so that the steering angle θh is controlled.