Vehicle Braking Device Dead Zone Control Strategy
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Solution Overview
Problem
The vehicle braking device frequently enters a dead zone due to its control mechanism, leading to repetitive stepwise changes in hydraulic pressure, which affects the control performance.
Innovation Solution
The device implements a control strategy where the actual hydraulic pressure follows a first target value when outside the dead zone and suppresses changes when within the dead zone, using a second target value set below the first target value to prevent entering the dead zone, thereby improving pressure adjustment control performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the control hydraulic pressure is continuously adjusted based on pressure deviation between target and actual values, then the pressure control responsiveness is improved, but the control system frequently enters the dead zone causing stepwise pressure changes
Solution Approach 1:
The control system performs preliminary action by predicting future pressure trends and adjusting the target hydraulic pressure in advance before the actual pressure enters the dead zone. This predictive approach prevents the oscillation problem while maintaining responsive control, as the system proactively adjusts parameters to avoid the problematic dead zone region rather than reactively responding after entry.
2Stability of the object's composition
If a dead zone is defined for pressure control, then the control system stability is improved, but the actual pressure value frequently enters and exits the dead zone causing repetitive operations
Solution Approach 1:
The system dynamically changes control parameters by adjusting the target hydraulic pressure based on the rate of change and magnitude of actual pressure deviation. When the actual pressure approaches the dead zone, the target pressure is modified to create a buffer, effectively changing the control parameter to prevent dead zone entry while maintaining overall control stability and improving adjustment efficiency.
3Measurement precision
If the target hydraulic pressure is set to precisely match the desired braking force, then the braking control precision is improved, but the actual pressure enters the dead zone more frequently
Solution Approach 1:
The control system applies preliminary anti-action by anticipating dead zone entry and counteracting it through target pressure adjustment before the actual pressure reaches the problematic region. When the actual pressure is approaching the dead zone boundaries, the target pressure is shifted to create a preventive buffer, thereby eliminating the harmful effect of frequent dead zone entry while preserving braking force control precision.
Data Source
AI summary
A vehicle braking device performs a following control which makes an actual value of a physical quantity follow a first target value when the actual value of the physical quantity is a value outside a dead zone and a suppression control which suppresses a change of the actual value when the actual value is a value within the dead zone in order to control the physical quantity associated with the braking force to be the first target value. The vehicle braking device comprises a setting portion which sets a second target value which follows the first target value and which is smaller than the first target value, when the first target value is increasing and a control portion which performs a control to make the actual value approximate the second target value.