Vehicle Acceleration Control During Regenerative-Brake Switching
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Solution Overview
Problem
Existing vehicle control systems experience discomfort due to fluctuations in vehicle acceleration during transitions between regenerative and friction braking modes, caused by differences in responsiveness between the driving and braking devices.
Innovation Solution
A vehicle controller and method that calculates a feedback control amount to manage the switching between driving and braking devices, allowing for a controlled transition by increasing the permitted deviation during the switch and adjusting the feedback control to accommodate the lower responsiveness of the braking device, thereby reducing acceleration fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If feedback control is executed with strict deviation limits to maintain precise acceleration control, then acceleration control precision is improved, but acceleration fluctuations occur during device switching causing occupant discomfort
Solution Approach 1:
The patent dynamically adjusts the dead band width based on the operating state of the driving and braking devices. When switching from the first device to the second device, the dead band width is increased to accommodate the transition and reduce fluctuations. This dynamic adjustment resolves the contradiction by adapting the control precision to the current operational context.
Solution Approach 2:
The patent changes the parameter of dead band width in response to device switching events. By increasing the dead band width during transitions between driving and braking devices, the system allows for greater deviation temporarily, preventing acceleration fluctuations and occupant discomfort while maintaining precision during stable operation.
2Object-affected harmful factors
If the dead band width is increased to reduce acceleration fluctuations during switching, then ride comfort is improved, but acceleration control precision deteriorates
Solution Approach 1:
The dead band width is not fixed but dynamically adjusted based on the operational state. It is widened during device transitions to reduce fluctuations and then narrowed during stable operation to maintain precision. This dynamic behavior resolves the contradiction by applying different dead band widths at different times.
Solution Approach 2:
The system periodically adjusts the dead band width in response to switching events between driving and braking devices. The dead band is temporarily increased during transitions and then returns to normal, creating a periodic pattern of adjustment that balances comfort and precision requirements.
Data Source
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AI summary
A vehicle controller includes a controlling unit. The controlling unit calculates a feedback control amount based on a deviation between a target acceleration of a vehicle and an actual acceleration of the vehicle. The controlling unit executes a feedback control of a driving device and a braking device by using the feedback control amount, such that the deviation decreases. A state in which only the driving device, of the driving device and the braking device, operates is a first state. A state in which at least the braking device, of the driving device and the braking device, operates is a second state. When switched from the first state to the second state, the controlling unit calculates the feedback control amount such that the deviation permitted in the feedback control is greater than the deviation prior to a start of switching from the first state to the second state.