EV Motor Stop Torque Control for Gradient Vibration Damping
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Solution Overview
Problem
Existing electric vehicle control methods experience decreased control stability and continuous vibration during stopping, particularly on gentle upward gradients due to the influence of road surface conditions, which affects the convergence of torque command values and leads to instability in the vibration damping process.
Innovation Solution
An electric vehicle control method that includes a disturbance torque estimation process, speed parameter acquisition, and a vehicle state control with a stop process to converge torque command values to a disturbance torque estimation value, and a vibration damping process that filters the stopping basis torque target value to improve stability, by setting the torque command value based on different torque target values in distinct speed ranges during the stopping process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a predetermined linear filter is set to the torque target value in the vibration damping process, then vibration suppression is achieved, but control stability decreases and continuous vibration occurs on gentle upward gradients
Solution Approach 1:
The patent applies dynamics by making the filter application conditional rather than static. The control device determines whether to apply the linear filter based on vehicle speed thresholds and road gradient conditions. When the vehicle speed is below a first threshold and the road gradient is within a specific range, the filter is applied; otherwise, it is not applied. This dynamic adjustment resolves the contradiction by adapting the vibration suppression mechanism to actual operating conditions, preventing continuous vibration on gentle upward gradients while maintaining effectiveness on appropriate road surfaces.
Solution Approach 2:
The patent changes the parameter of filter application based on operating conditions. By monitoring vehicle speed and road gradient parameters, the system dynamically adjusts whether the linear filter is applied to the torque target value. This parameter-based control allows the system to switch between filtered and unfiltered torque commands, resolving the stability-vibration suppression contradiction by optimizing the filter application to specific operational contexts.
2Productivity
If the torque command value converges to the disturbance torque estimation value in accordance with speed decrease, then stopping performance is improved, but control stability deteriorates under certain road surface conditions
Solution Approach 1:
The patent implements feedback by continuously monitoring vehicle speed, road gradient, and torque command values during the stopping process. The control device uses this feedback to determine whether to apply the linear filter to the torque target value. This feedback mechanism ensures that the convergence of torque command to disturbance torque estimation is stabilized under appropriate conditions while preventing instability on gentle upward gradients, thus resolving the contradiction between stopping performance and control stability.
Data Source
AI summary
An electric vehicle control method for controlling a motor based on a torque command value in an electric vehicle includes: a disturbance torque estimation process of calculating a disturbance torque estimation value including an influence of a road surface gradient; a speed parameter acquisition process of acquiring a speed parameter relating to a vehicle speed; and a vehicle state control including a stop process of calculating a stopping basis torque target value so as to converge the torque command value to the disturbance torque estimation value in accordance with a decrease in the speed parameter, and a vibration damping process of calculating a stopping correction torque target value by performing filtering on the stopping basis torque target value.