Vehicle Steering Torque Correction for Slippery Road Guidance
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Solution Overview
Problem
Existing vehicle control systems face challenges in accurately guiding a vehicle in a target traveling direction on slippery roads, leading to steering torque deviations that can cause driver anxiety and delay in achieving the intended steering angle.
Innovation Solution
A vehicle control apparatus that uses a combination of braking/driving force control and steering torque correction, calculated based on vehicle behavior, to accurately guide the vehicle while minimizing driver anxiety, employing a system with a CPU, ROM, RAM, and sensors for real-time data processing and actuator control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If steering torque is increased to prevent steering error and guide vehicle in target direction, then vehicle guidance accuracy is improved, but driver anxiety increases and steering feels unnatural
Solution Approach 1:
The system dynamically changes the steering torque parameter based on vehicle behavior parameters (lateral acceleration, yaw rate). When vehicle behavior deviates from target, steering torque is adjusted to correct the deviation while maintaining natural steering feel. This resolves the contradiction by making steering torque adaptive rather than fixed, allowing accurate guidance without causing driver anxiety.
2Object-affected harmful factors
If steering torque is reduced to ease driver anxiety, then driver comfort is improved, but vehicle guidance accuracy deteriorates and steering angle conversion is delayed
Solution Approach 1:
The steering torque control system transitions from static to dynamic operation. The control unit continuously monitors vehicle behavior (lateral acceleration, yaw rate) and adjusts steering torque in real-time based on the degree of deviation from target traveling direction. This dynamic adjustment ensures accurate vehicle guidance while maintaining natural steering feel, resolving the contradiction between guidance accuracy and driver comfort.
3Object-affected harmful factors
If steer-by-wire system is implemented to guide vehicle without changing steering torque, then system complexity increases, but steering naturalness is maintained
Solution Approach 1:
The patent introduces a control unit as an intermediary between the driver's steering input and the vehicle's actual steering response. This control unit calculates appropriate steering torque based on vehicle behavior parameters and applies it through the existing steering system. This intermediary approach maintains steering naturalness without requiring a complete steer-by-wire system, thus resolving the contradiction while minimizing system complexity.
4Measurement precision
If braking/driving force control is used to guide vehicle in target direction, then vehicle guidance capability is improved, but steering torque deviation occurs causing driver discomfort
Solution Approach 1:
The system merges braking/driving force control with steering torque correction control. The control unit simultaneously manages both the braking/driving forces applied to individual wheels and the steering torque applied to the steering system. This combined control approach ensures accurate vehicle guidance while compensating for steering torque deviations, thereby eliminating driver discomfort and resolving the contradiction between guidance capability and driver comfort.
Data Source
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AI summary
A vehicle control apparatus according to the present invention outputs a signal regarding a target braking/driving force for guiding a vehicle in a target traveling direction to a braking/driving controller. The signal regarding the target braking/driving force is acquired based on information regarding a running route of the vehicle and a physical amount regarding a motion state of the vehicle. The vehicle control apparatus outputs a signal regarding a steering correction torque for correcting a steering torque according to a behavior of the vehicle to a steering force controller. The signal regarding the steering correction torque is acquired based on a vehicle-body slip angle of the vehicle and the target braking/driving force.