EV Towing Torque Control for Longitudinal Vibration Damping
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Solution Overview
Problem
Existing control methods for electric vehicles fail to adequately reduce vibration when towing another vehicle, due to insufficient consideration of the changed torque transmission characteristic caused by the increased vehicle weight during towing.
Innovation Solution
A control method that calculates a final torque command value by performing correction processing based on the dynamic characteristic of the coupling portion to reduce the longitudinal vibration component, ensuring effective vibration damping even during towing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If vibration damping control is performed based on the torque transmission characteristic of the power transmission mechanism, then vibration caused by road surface gradient, gear backlash, and torsion of drive shaft is reduced, but vibration caused by towing another vehicle is not sufficiently reduced due to large change in vehicle weight
Solution Approach 1:
The control system dynamically switches between two different torque transmission characteristics: one for normal driving conditions and another for towing conditions. This allows the system to adapt to the large change in vehicle weight when towing another vehicle, thereby effectively reducing vibration in both normal and towing scenarios.
Solution Approach 2:
The system changes the torque transmission characteristic parameters based on the detected towing condition. By detecting the presence of another vehicle being towed and switching to an appropriate torque transmission characteristic, the system optimizes vibration damping performance for the specific operating condition.
2Reliability
If the torque transmission characteristic is modeled based on the weight of the electric vehicle, then vibration damping control can be performed for normal driving, but sufficient vibration damping effect cannot be obtained when there is large change in vehicle weight due to towing
Solution Approach 1:
The control system uses dynamic switching between pre-stored torque transmission characteristics instead of relying solely on a fixed model based on vehicle weight. This allows the system to maintain reliable vibration damping effects across a wide range of weight conditions, including towing scenarios where the vehicle weight changes significantly.
Solution Approach 2:
The system pre-stores multiple torque transmission characteristics corresponding to different operating conditions (normal driving and towing). By having these characteristics prepared in advance and switching between them based on detected conditions, the system ensures reliable vibration damping without needing to recalculate models in real-time during weight changes.
3Device complexity
If the torque transmission characteristic is determined by the structure of the power transmission mechanism, then the control system is simple, but it does not reflect the presence or absence of towing and vibration cannot be sufficiently reduced
Solution Approach 1:
The control system implements dynamic switching between different torque transmission characteristics based on detected towing conditions. This adds minimal complexity (a switching mechanism and condition detector) while significantly improving vibration reduction capability by adapting to different operating scenarios.
Solution Approach 2:
The system changes the torque transmission characteristic parameters based on the detected presence or absence of towing. This simple parameter switching approach allows the system to reflect towing conditions and effectively reduce vibration without requiring complex real-time calculations or additional mechanical components.
Data Source
AI summary
An electric vehicle includes a motor as a drive source and a coupling portion coupled to another vehicle, and travels while towing the coupled vehicle, which is the other vehicle coupled to the coupling portion. A control method for such an electric vehicle includes: calculating a basic torque target value representing a torque to be output by the motor based on a vehicle operation; calculating a final torque command value, which is a final command value for the torque, by performing correction processing for reducing a longitudinal vibration component generated in the electric vehicle due to the coupled vehicle being coupled to the coupling portion on the basic torque target value, based on a dynamic characteristic of the coupling portion to which the coupled vehicle is coupled; and controlling the motor based on the final torque command value.