Vehicle Acceleration Control with Smooth Target Convergence
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Solution Overview
Problem
Conventional vehicle acceleration control systems that increase target acceleration to improve response can cause unexpected acceleration greater than expected by the driver, making driving difficult and uncomfortable.
Innovation Solution
A vehicle control system that sets a first target acceleration based on the accelerator opening degree and a second target acceleration greater than the first, with a control device adjusting the second acceleration to converge to the first when the accelerator opening degree change rate decreases, using a convergence speed determined by the accelerator opening degree and first target acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the target acceleration is increased to improve acceleration response, then the acceleration response is improved, but the acceleration becomes greater than expected by the driver, making driving operation difficult
Solution Approach 1:
The patent applies dynamics by making the target acceleration adjustable and time-varying. The control device switches between a first target acceleration (for normal operation) and a second target acceleration (for improved response). The second target acceleration is temporarily applied only during the initial phase after accelerator pedal depression, then smoothly transitioned back to the first target acceleration. This dynamic adjustment allows the system to optimize acceleration response when needed while returning to normal operation afterward, resolving the contradiction between improved response and ease of operation.
2Speed
If the second target acceleration is continuously used during acceleration, then the acceleration response is improved, but the driver feels uncomfortable due to unexpected acceleration
Solution Approach 1:
The patent applies periodic action by using the second target acceleration only for a limited time period after accelerator pedal depression, rather than continuously. The control device detects when the accelerator pedal is depressed and applies the second target acceleration during this initial period. After a predetermined time elapses or when acceleration becomes excessive, the system transitions back to the first target acceleration. This time-limited application provides improved response initially while preventing prolonged unexpected acceleration that would cause driver discomfort.
Solution Approach 2:
The patent applies feedback by continuously monitoring the accelerator pedal depression state and the current acceleration level. The control device uses this feedback information to determine when to switch between the first and second target accelerations. When the accelerator pedal is depressed and acceleration is below a threshold, the second target acceleration is applied. When the acceleration exceeds the threshold or the pedal is released, the system transitions back to the first target acceleration. This feedback mechanism ensures the improved acceleration is applied only when appropriate and prevents excessive acceleration that would discomfort the driver.
3Ease of operation
If the target acceleration is returned to the original value during acceleration, then the acceleration becomes manageable, but the transition may cause uncomfortable feeling for the driver
Solution Approach 1:
The patent applies beforehand cushioning by preparing for the transition between target accelerations in advance. Before switching from the second target acceleration back to the first target acceleration, the control device calculates a transition period and uses intermediate acceleration values to bridge the gap. This cushioning approach prevents abrupt changes in acceleration that would startle or discomfort the driver. The system anticipates the need to reduce acceleration and smoothly phases the transition, maintaining driver comfort while restoring manageable acceleration levels.
Data Source
AI summary
A vehicle control system includes a drive source, an accelerator opening degree sensor that detects an accelerator opening degree, and a control device that controls the drive source based on the accelerator opening degree. The control device obtains a first target acceleration corresponding to the accelerator opening degree and obtains a second target acceleration greater than the first target acceleration, controls the torque of the drive source based on the first or second target accelerations, adjusts the second target acceleration to gradually converge to the first target acceleration based on the first target acceleration and a rate of change of the accelerator opening degree when the rate of change has decreased by a predetermined value or more from an increasing state during control of the torque of the drive source based on the second target acceleration, and controls the torque of the drive source based on the second target acceleration.