EV Gradient Torque Control for Consistent Pedal Response
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vehicle acceleration/deceleration control systems cause driver discomfort by adjusting acceleration/deceleration based on road gradients, leading to inconsistent driver input and vehicle response.
Innovation Solution
An electric vehicle control method that estimates disturbance torque related to road gradients and adjusts braking or driving force to minimize gradient correction, reducing the sense of discomfort by determining if the accelerator operation is equivalent to a partial-state and adjusting the correction amount accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If gradient correction is executed to maintain constant vehicle speed on gradient roads, then vehicle speed stability is improved, but driver comfort deteriorates due to unexpected acceleration/deceleration when accelerator operation changes
Solution Approach 1:
The system dynamically adjusts the gradient correction amount based on the accelerator operation amount. When the accelerator operation amount changes (indicating driver intent to accelerate or decelerate), the gradient correction is reduced or canceled, allowing the vehicle acceleration/deceleration to reflect the driver's input rather than being overridden by gradient compensation.
Solution Approach 2:
The control system changes the parameter of gradient correction amount based on the accelerator operation amount. By monitoring the accelerator operation amount and adjusting the correction level accordingly, the system transitions between full gradient compensation (for speed maintenance) and reduced compensation (for driver-responsive acceleration/deceleration).
2Stability of the object's composition
If gradient correction increases target acceleration on ascending gradients, then vehicle speed maintenance is improved, but driver intent recognition deteriorates when driver reduces accelerator operation to decelerate
Solution Approach 1:
The system uses feedback from the accelerator operation amount to determine whether to apply full gradient correction. When the driver reduces accelerator operation (indicating deceleration intent), the system detects this change and reduces the gradient correction amount, preventing the correction from overriding the driver's deceleration command.
3Stability of the object's composition
If gradient correction reduces target acceleration on descending gradients, then vehicle speed control is improved, but driver input consistency deteriorates when driver increases accelerator to accelerate
Solution Approach 1:
The gradient correction amount is dynamically reduced when the accelerator operation amount increases on descending gradients. This allows the vehicle to respond to the driver's acceleration intent rather than having the acceleration suppressed by gradient compensation, maintaining consistency between driver input and vehicle response.
Data Source
AI summary
A control method for an electric vehicle controls braking force when the accelerator operation amount is less than a prescribed value and controls drive force when the accelerator operation amount is at least a prescribed value. The electric vehicle control method estimates disturbance torque that acts on the motor as a resistance component relating to gradient; and executes correction whereby the braking force or the drive force is increased/decreased on the basis of the disturbance torque estimated value, such that the resistance component is negated. A determination is made regarding whether or not the accelerator operation amount is a partial equivalent amount and, if at least either the accelerator operation amount on a downhill road is greater than the partial equivalent amount or the accelerator operation amount on an uphill road is less than the partial equivalent amount, the correction amount is reduced.