Vehicle Control Device Braking Force Switching
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Solution Overview
Problem
Existing vehicle control systems experience shocks during braking-force switching in cruise control mode, particularly on rough or gradient-varying road surfaces, due to changes in target braking force with vehicle speed.
Innovation Solution
A vehicle control device with a controller that manages both braking devices and driving motors, executing braking control by initially using only braking devices and then switching to regenerative braking once vehicle speed stabilizes, thereby reducing shocks by adjusting braking forces accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is used during cruise control mode, then energy recovery is improved, but vehicle speed stability deteriorates causing shocks
Solution Approach 1:
The controller determines whether vehicle speed has stabilized before initiating regenerative braking. This preliminary check ensures that regenerative braking is only activated when vehicle speed changes are within a predetermined threshold, preventing shocks caused by premature activation during unstable speed conditions.
Solution Approach 2:
The system continuously monitors vehicle speed and compares it against the predetermined threshold to determine stability. This feedback mechanism allows the controller to make informed decisions about when to activate or deactivate regenerative braking, maintaining both energy recovery efficiency and vehicle speed stability.
2Device complexity
If braking device is used exclusively, then vehicle speed control is simple, but energy recovery is reduced
Solution Approach 1:
The system dynamically switches between braking device-only mode and regenerative braking mode based on real-time vehicle speed stability. When vehicle speed is stable, regenerative braking is activated to recover energy; when unstable, the system reverts to braking device-only control. This dynamic adaptation maintains control simplicity while maximizing energy recovery opportunities.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively suppresses shocks during braking-force switching in cruise control mode by stabilizing vehicle speed before transitioning to regenerative braking, ensuring smoother vehicle operation on varying road conditions.
Implementation Method 1
The braking control includes braking by the braking device and regenerative braking by the driving motor
Data Source
AI summary
A vehicle control device includes a controller configured to control operation of a braking device and operation of a driving motor. The controller can switch between a normal mode of controlling acceleration/deceleration in accordance with a driver's acceleration/deceleration operation, and a cruise control mode of maintaining the vehicle speed at a target speed without being dependent on the acceleration/deceleration operation. The controller is configured to execute braking control, including braking by the braking device and regenerative braking by the driving motor, during the cruise control mode in accordance with a change in a vehicle traveling condition. The braking control includes causing the braking device to generate a braking force without using the regenerative braking and subsequently executing a braking-force switching process including increasing a braking force by the regenerative braking while reducing the braking force from the braking device, if a determination result indicates that the vehicle speed is stable.