Electric Vehicle Gradient Correction for Driver Comfort
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Solution Overview
Problem
Existing vehicle acceleration/deceleration control systems cause discomfort to drivers on descending gradients due to excessive deceleration, as they correct deceleration based on road surface gradients, leading to unexpected large deceleration rates.
Innovation Solution
An electric vehicle control device that reduces the gradient correction amount on descending gradients by adjusting the gradient assist torque based on the road surface gradient, using a motor controller to calculate a disturbance torque value and adjust the target torque to minimize deceleration, thereby enhancing driver comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gradient correction is executed by correcting target acceleration/deceleration in accordance with the gradient of the road surface, then vehicle speed can be maintained constant on gradient roads, but large deceleration is generated on descending gradients causing driver discomfort
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the gradient correction amount based on the detected gradient value. When a descending gradient is detected, the correction amount is reduced compared to the standard gradient correction, thereby preventing excessive deceleration while still maintaining speed control functionality. This resolves the contradiction by adapting the correction parameter to the specific road condition.
2Measurement precision
If deceleration is corrected in accordance with the gradient of the road surface, then acceleration/deceleration can be controlled precisely, but unexpected large deceleration occurs on descending gradients
Solution Approach 1:
The patent applies local quality by implementing different correction strategies for different road gradient conditions. Specifically, when a descending gradient is detected, a reduced correction amount is applied locally to that condition, while standard correction applies to other conditions. This prevents excessive deceleration on descending gradients while maintaining precise acceleration control on flat or ascending roads.
Data Source
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AI summary
The electric vehicle control method is a control method that includes the motor that gives braking force or driving force to a vehicle in accordance with an accelerator operation, by which the braking force is controlled when an accelerator operation amount is smaller than a given value and the driving force is controlled when the accelerator operation amount is the given value or larger. The electric vehicle control device estimates disturbance torque that acts on the motor as resistance component relating to a gradient and executes correction by which the braking force or the driving force is increased or decreased so as to cancel the resistance component in accordance with a disturbance torque estimated value Td. Then, on a downhill road at a given gradient or more, a correction amount of the braking force or the driving force is reduced.