Vehicle Braking Device Dynamic Dead Zone Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The vehicle braking device often enters a dead zone, leading to frequent stepwise changes in control hydraulic pressure, causing uncomfortable deceleration sensations for drivers, especially when the target hydraulic pressure changes gradually.
Innovation Solution
The vehicle braking device employs a control mechanism that adjusts the dead zone thresholds to suppress changes in the actual hydraulic pressure when it is within the dead zone and follows the target value when outside the dead zone, using a judging portion to determine when to set a second upper limit threshold closer to the target value to prevent stepwise changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the control hydraulic pressure is always controlled based on the deviation in pressure between the target hydraulic pressure and the control hydraulic pressure, then the control hydraulic pressure easily enters the dead zone, but frequent repetition between holding operation and pressure increasing/decreasing operation occurs, leading to stepwise change in control hydraulic pressure
Solution Approach 1:
The patent dynamically adjusts the dead zone width based on the rate of change of target hydraulic pressure. When the target pressure changes gradually, a narrower dead zone is used to prevent stepwise changes. When the target pressure changes rapidly, a wider dead zone is applied to ensure stable control. This dynamic adjustment resolves the contradiction by adapting the control parameters to the current operating conditions.
Solution Approach 2:
The patent changes the parameter of dead zone width (threshold values) based on the rate of change of target hydraulic pressure. By modifying this control parameter dynamically, the system achieves both precise pressure control and smooth braking operation, eliminating the stepwise changes that occur with fixed threshold values.
2Device complexity
If a fixed dead zone is used for pressure control, then the control structure is simple, but stepwise changes in hydraulic pressure occur when target pressure changes gradually, causing uncomfortable deceleration sensation
Solution Approach 1:
The patent transforms the fixed dead zone into a dynamic parameter that adjusts based on the rate of change of target hydraulic pressure. This dynamic approach maintains relatively simple control structure while significantly improving braking comfort by preventing stepwise pressure changes during gradual target pressure transitions.
3Ease of operation
If the dead zone width is increased to suppress stepwise changes, then braking smoothness improves, but the response speed of pressure control decreases
Solution Approach 1:
The patent changes the dead zone width parameter dynamically based on the rate of change of target hydraulic pressure. When rapid response is needed, a narrower dead zone is used. When smoothness is prioritized during gradual changes, a wider dead zone is applied. This parameter adaptation resolves the contradiction between response speed and braking smoothness.
Data Source
AI summary
The vehicle braking device performs a control which makes an actual value of physical quantity associated with a braking force follow a target value thereof when the actual value is outside a dead zone and a control which suppresses a change of the actual value when the actual value is within the dead zone and includes a judging portion which judges whether or not the actual value passes through the dead zone with a value beyond the upper limit threshold value and a setting portion which sets a second upper limit threshold value more closely approximated than a first upper limit threshold value when the actual value is judged not to pass through the dead zone, as the upper limit threshold value, when the actual value is judged to pass through the dead zone by the judging portion.