Dynamometer Load Balance Control for Transient Responsiveness
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Solution Overview
Problem
Existing control devices for dynamometer systems face challenges in maintaining responsiveness during transient conditions, such as acceleration and braking, especially when the load balance of the front-rear wheels differs.
Innovation Solution
A control device that includes a uniform-speed synchronization controller, drive force estimators, a load balance processor, and torque current command generators. The load balance processor independently varies the load balance correction inputs based on the estimated drive forces, ensuring that the speed difference between the wheels is minimized during transient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric inertia controller determines the input to the front-rear dynamometers based on the ratio of the sum of the front-wheel mechanical inertia and rear-wheel mechanical inertia relative to the vehicle inertia, then the system can maintain stable operation under normal conditions, but the responsiveness declines during transient conditions such as acceleration and braking when the load balance of front-rear wheels differs
Solution Approach 1:
The control system dynamically switches between two control modes: using the electric inertia controller output during normal conditions, and using the synchronization controller output during transient conditions when responsiveness is needed. This dynamic adaptation allows the system to maintain both reliability and responsiveness under different operating conditions.
Solution Approach 2:
The system changes the control parameter by selecting different control strategies based on the operating state. During transient conditions, it switches from the inertia-based control parameter to the synchronization-based control parameter, which prioritizes speed matching and responsiveness over inertial stability.
2Stability of the object's composition
If the synchronization controller eliminates the speed difference between front-wheel speed and rear-wheel speed, then the wheels maintain equal speeds, but the system cannot adequately respond to transient load changes during acceleration and braking
Solution Approach 1:
The system uses feedback from the drive force observer to detect transient conditions and adjusts the control strategy accordingly. When transient conditions are detected, the feedback mechanism switches the control priority from maintaining speed equality to responding to load changes, thereby improving responsiveness while preserving the ability to maintain speed equality during normal operation.
3Speed
If the load balance correction inputs are independently adjusted based on estimated drive forces, then the responsiveness during transient conditions is improved, but the control system complexity increases
Solution Approach 1:
The control system is segmented into distinct functional modules: the drive force observer that estimates drive forces, the synchronization controller that manages speed equality, and the electric inertia controller that handles normal operation. This segmentation allows independent adjustment of load balance correction inputs while keeping each module's complexity manageable.
Solution Approach 2:
The drive force observer acts as an intermediary that provides estimated drive forces to both the synchronization controller and the electric inertia controller. This intermediary component enables independent adjustment of control parameters based on real-time drive force estimation without requiring direct complex interaction between the controllers themselves.
Data Source
AI summary
This control device 6 comprises a uniform-speed synchronization control unit 63 for generating a synchronization correction input Fd for front-wheel and rear-wheel dynamometers so that a difference between front and rear speeds is eliminated, a load balance computation unit 62 for generating a front-wheel load balance correction input Ffil_f and a rear-wheel load balance correction input Ffil_r, a front-wheel torque current command generation unit 64f for generating a front-wheel torque current command on the basis of the inputs Ffil_f and Fd, and a rear-wheel torque current command generation unit 64r for generating a rear-wheel torque current command on the basis of the inputs Ffil_r and Fd. The load balance computation unit 62 causes the inputs Ffil_f and Ffil_r to change independently of one another, raises the input Ffil_f a rear-wheel drive force Fvr increases, and raises the input Ffil_r as a rear-wheel drive force Fvf increases.