Vehicle Control Device Dead Zone Compensation
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Solution Overview
Problem
Existing vehicle control systems face challenges in maintaining linearity and robustness against disturbance factors, such as variations in road friction and tire characteristics, leading to unsuitable actuator control and potential overheating of braking systems due to frequent braking, resulting in nonlinear control characteristics and reduced robustness.
Innovation Solution
A vehicle control device that includes a drive manipulated variable detector, an actuator device controller, an actual state amount grasper, a model state amount determiner, a state amount error calculator, and error response controllers to approximate state amount errors to zero, using feedback and feedforward controls and dead zone management to stabilize vehicle motion and prevent actuator overactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If frequent braking is used for automatic vehicle control, then vehicle motion can be stabilized, but the braking system becomes hot and exhibits nonlinear characteristics reducing robustness
Solution Approach 1:
The patent applies preliminary anti-action by introducing a dead zone compensation mechanism that anticipates and counteracts the nonlinear effects of frequent braking. The compensation value is calculated in advance based on the cumulative braking amount, and this compensation is applied to the braking control input before execution, thereby pre-counteracting the thermal nonlinearities that would otherwise degrade control robustness.
Solution Approach 2:
The patent implements feedback by continuously monitoring the cumulative braking amount and using this information to dynamically adjust the dead zone compensation value. The feedback loop compares the actual braking behavior with the expected linear response, and the compensation mechanism adjusts the control input to maintain robustness against the nonlinear thermal effects accumulated over time.
2Extent of automation
If reference state amounts are generated using a vehicle model, then control can be automated, but disturbance factors cause the reference state to be remote from actual vehicle behavior
Solution Approach 1:
The patent applies feedback by continuously comparing the actual vehicle state with the model-based reference state and using the cumulative deviation information to adjust future control commands. The feedback mechanism incorporates the cumulative braking amount and other disturbance indicators to dynamically correct the reference trajectory, ensuring it remains aligned with actual vehicle behavior despite modeling inaccuracies.
Solution Approach 2:
The patent implements parameter changes by dynamically adjusting the dead zone compensation parameter based on the cumulative braking amount and detected disturbance factors. This allows the control system to adapt its characteristics in real-time, changing the effective dead zone size to compensate for thermal nonlinearities and maintain control accuracy under varying operating conditions.
3Temperature
If a dead zone is provided in braking control, then actuator overheating is prevented, but control system linearity is reduced
Solution Approach 1:
The patent introduces a dead zone compensation value as an intermediary element that mediates between the braking control input and the actual braking application. This compensation value acts as a buffer that accounts for the nonlinear dead zone effects, allowing the control system to maintain linearity in the overall control loop while still providing the necessary dead zone protection against actuator overheating.
Solution Approach 2:
The patent dynamically changes the dead zone compensation parameter based on the cumulative braking amount and thermal state of the braking system. By adjusting this parameter in real-time, the system can maintain optimal linearity compensation while adapting to changing thermal conditions, ensuring both protection against overheating and preservation of control linearity.
Data Source
AI summary
An FB distribution rule 20 determines an actual vehicle actuator operation control input and a vehicle model operation control input such that a difference between a reference state amount determined by a vehicle model 16 and an actual state amount of an actual vehicle 1 (a state amount error) approximates to zero, and the control inputs are used to operate an actuator device 3 of the actual vehicle 1 and the vehicle model 16. In the FB distribution law 20, when an actual vehicle feedback required amount based on the state amount error exists in a dead zone, then an actual vehicle actuator operation control input is determined by using the required amount as a predetermined value. A vehicle model manipulated variable control input is determined such that a state amount error is brought close to zero, independently of whether an actual vehicle feedback required amount exists in a dead zone. This enhances linearity of a control system and also enhances the robustness against disturbance factors or changes therein while carrying out operation control of an actuator that suits a behavior of an actual vehicle as much as possible.