Vehicle Braking Force Control for Steady-State Posture Stability
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Solution Overview
Problem
Existing vehicle control systems that adjust braking force based on roll angle can inadvertently increase braking force during steady steering, leading to unintended vehicle speed reduction.
Innovation Solution
A device that includes a sensor to detect the rudder angle, a processor to calculate and correct the target braking force by reducing it with an offset amount when the steering action is in a steady state, and an actuator to apply the corrected force, ensuring stable vehicle posture and preventing unintended speed reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If braking force is controlled based on roll angle to maintain vehicle posture, then vehicle posture stability is improved, but braking force may gradually increase during steady steering causing unintended vehicle speed reduction
Solution Approach 1:
The patent applies dynamics by making the braking force control system adaptive to different steering states. The control device dynamically adjusts braking force based on whether the steering angle is changing or steady, transitioning between two control modes: pitch angle control during steering input and vehicle speed control during steady steering. This dynamic adaptation resolves the contradiction by maintaining posture stability during maneuvering while preventing unintended speed reduction during steady-state operation
Solution Approach 2:
The patent changes the control parameter from fixed pitch angle control to variable control based on steering state. When the steering angle derivative exceeds a threshold, the system controls pitch angle; when it remains below the threshold, the system controls vehicle speed. This parameter change allows the system to maintain posture stability when needed while preventing unwanted speed reduction during steady steering
2Stability of the object's composition
If pitch angle control is implemented during steering, then vehicle posture is stabilized, but braking force increases even when driver does not operate brake pedal
Solution Approach 1:
The patent implements feedback by continuously monitoring the steering angle derivative to determine the current steering state. This feedback mechanism allows the control device to distinguish between active steering input and steady-state steering, automatically switching control strategies accordingly. The feedback ensures that pitch angle control is applied only when the driver is actively steering, maintaining intuitive brake operation while still providing posture stability when needed
Solution Approach 2:
The system dynamically switches between control modes based on real-time steering state detection. When the steering angle derivative indicates active steering input, pitch angle control is activated; when the derivative shows steady-state conditions, vehicle speed control takes over. This dynamic switching resolves the contradiction by making pitch angle control context-dependent, ensuring it operates only when intuitively appropriate
Data Source
AI summary
A device 10 for controlling a vehicle 1 includes: a sensor 20 configured to detect a rudder angle; a calculation part 40a configured to calculate a target braking force for making a pitch angle equal to a target pitch angle, the target braking force increasing as the rudder angle increases; a determination part 40b configured to determine whether a steering action is in a steady state; a correction part 40c configured to correct the target braking force to be reduced by an offset amount when it is determined that the steering action is in a steady state; and an actuator 30 configured to apply the corrected target braking force to the vehicle.