Electric Vehicle Accelerator Pedal Control Device for Stable Behavior
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Solution Overview
Problem
The behavior of electric vehicles during the returning operation of the accelerator pedal is unstable due to varying control switching based on the depression amount, causing a sense of incongruity for the driver.
Innovation Solution
A control device that switches among types of control for the travel motor during the returning operation of the accelerator pedal by setting specific regions for coasting, regeneration, and power running based on the depression amount, stabilizing vehicle behavior regardless of the starting depression amount.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If control over the travel motor is switched based on the depression amount when the accelerator pedal is depressed to full openness, then the control can be simplified, but the behavior of the electric vehicle during the returning operation becomes unstable
Solution Approach 1:
The patent applies dynamics by making the control switching threshold adaptive rather than fixed. The coasting region threshold is dynamically adjusted based on the depression amount at the start of the returning operation, allowing the control system to adapt to different operating conditions and maintain stable vehicle behavior throughout the pedal return process.
Solution Approach 2:
The patent changes the parameter used for control switching from a fixed depression amount threshold to a dynamic threshold based on the starting depression amount. By calculating the coasting region threshold as a proportion of the actual depression amount at the start of returning operation, the system maintains appropriate control transitions regardless of the initial pedal position.
2Ease of operation
If the control switching threshold is fixed at a constant depression amount, then the control logic is simplified, but the timing of control switching varies greatly depending on the starting depression amount, causing unstable vehicle behavior
Solution Approach 1:
The patent transforms the fixed parameter approach into a proportional parameter approach. Instead of using a constant depression amount threshold, the coasting region threshold is defined as a fixed proportion (e.g., 50%) of the starting depression amount, maintaining control logic simplicity while ensuring consistent control switching timing relative to the pedal return progress.
Solution Approach 2:
The system dynamically determines the coasting region threshold based on the actual starting conditions of each pedal return operation. This dynamic adjustment ensures that the control switching occurs at the appropriate moment regardless of whether the pedal was fully depressed or only partially depressed before returning.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A control device of an electric vehicle comprises: an operating state detection unit for detecting the operating state of an accelerator pedal; a motor control unit for executing deceleration control over a travel motor, including coasting control which reduces the driving force of the travel motor to zero, when the returning operation of the accelerator pedal is detected by the operating state detection unit; and a region setting unit for setting the range of the depression amount of the accelerator pedal for executing the coasting control, based on the depression amount of the accelerator pedal at the start of the returning operation of the accelerator pedal. The control device can switch among the types of control over the travel motor during the returning operation of the accelerator pedal, while suppressing a driver's sense of incongruity.