Vehicle Accelerator Control Hysteresis Management
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Solution Overview
Problem
Conventional vehicle control systems experience discomfort and reduced responsiveness when employing hysteresis control, particularly when the accelerator pedal is deeply depressed and then returned, due to a decrease in operation gain at wider accelerator openings, leading to uneven acceleration changes that are not effectively communicated to the driver.
Innovation Solution
A vehicle control system that sets different target accelerations for accelerator pedal depression and return under the same accelerator opening conditions, with upper and lower limit accelerations to restrict the difference and ensure adequate responsiveness, incorporating a processor to manage these settings based on detected accelerator openings, vehicle speed, and road surface gradient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If hysteresis control is employed to provide adequate responsiveness when the accelerator pedal is deeply depressed and returned, then the operation gain increases and acceleration changes become more noticeable, but the difference in acceleration characteristics between depression and return becomes enlarged causing driver discomfort
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the target acceleration based on the accelerator opening change rate. When the accelerator opening changes rapidly (deep depression or quick return), the system increases the target acceleration to enhance responsiveness. When the change rate is moderate, it limits the target acceleration to prevent excessive difference between depression and return characteristics, thereby reducing driver discomfort.
Solution Approach 2:
The patent implements dynamics by making the target acceleration setting adaptive rather than fixed. The control system continuously monitors the accelerator opening change rate and adjusts the target acceleration accordingly. This dynamic adjustment allows the system to provide high responsiveness when needed (rapid pedal movements) while maintaining comfort during normal operations, effectively resolving the contradiction between responsiveness and comfort.
2Power
If the target acceleration is set to increase as the accelerator opening becomes wider, then the power output increases, but the operation gain decreases at wider openings making acceleration changes difficult to perceive
Solution Approach 1:
The patent changes the parameter of target acceleration based on the accelerator opening change rate. When the accelerator opening changes rapidly, the system sets a higher target acceleration to maintain noticeable acceleration changes even at wide openings where operation gain would naturally decrease. This compensates for the reduced operation gain while preserving the increased power output.
Solution Approach 2:
The system uses feedback from the accelerator opening change rate to adjust the target acceleration. By monitoring how quickly the accelerator opening changes, the system can compensate for decreasing operation gain at wide openings, ensuring that acceleration changes remain perceptible to the driver while maintaining high power output when needed.
Data Source
AI summary
A vehicle control system includes an accelerator sensor which detects an accelerator opening, and a processor which sets a target acceleration of a vehicle based on the detected accelerator opening, sets a target torque of a drive source based on the set target acceleration, and controls the drive source to generate the set target torque. In a case where the target acceleration at a time when the accelerator opening is increased is set as a depression-increasing target acceleration and the target acceleration at a time when the accelerator opening is decreased is set as a pedal-returning target acceleration, under the same condition of the accelerator opening, the processor sets the target acceleration such that the depression-increasing target acceleration and the pedal-returning target acceleration are different from each other in a predetermined range of an upper limit acceleration or less and a lower limit acceleration or greater.