Hybrid Vehicle Deceleration Control via Dynamic Torque Ratio
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Solution Overview
Problem
Hybrid vehicles face challenges in precisely controlling deceleration, especially during deceleration events, as existing methods struggle to balance open-loop and closed-loop control, affecting drivability and regenerative energy recovery.
Innovation Solution
A method using a control unit to output feed forward torque based on a map table and adjust the application ratio of feedback torque, combining feed forward and feedback control to calculate final control torque for precise deceleration, incorporating deceleration event information from navigation systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If only feedback control is used for deceleration, then the control system is simple, but the deceleration precision and drivability are insufficient
Solution Approach 1:
The patent combines feedforward control and feedback control into a hybrid control system. The feedforward control uses pre-stored torque values from a map table based on current velocity and target velocity, while feedback control adjusts based on the actual velocity difference. This merging of open-loop and closed-loop control achieves precise deceleration without requiring overly complex control logic.
Solution Approach 2:
The patent implements preliminary action by pre-calculating and storing feedforward torque values in a map table before actual deceleration events occur. The map table contains torque values corresponding to various velocity and target velocity combinations, allowing the system to quickly retrieve appropriate torque values during deceleration without real-time calculation delays.
2Speed
If feed forward torque is applied with high application ratio, then the initial deceleration response is improved, but the precision near target velocity deteriorates
Solution Approach 1:
The patent makes the feedforward torque application ratio dynamic rather than fixed. The adjustment factor output unit dynamically adjusts the application ratio based on the velocity difference between current and target velocity. When velocity difference is large, the application ratio is high for fast response; when velocity difference is small, the application ratio is reduced to allow feedback control to dominate for precise control near the target velocity.
Solution Approach 2:
The patent changes the parameter of feedforward torque application ratio based on operating conditions. By adjusting this parameter dynamically according to velocity difference and residual distance, the system optimizes the balance between rapid deceleration response and precise velocity control at different stages of the deceleration process.
3Measurement precision
If feedback torque is output early, then the velocity control is precise, but the drivability and energy recovery are reduced
Solution Approach 1:
The patent applies feedforward control as a preliminary action before feedback control takes over. The feedforward torque is output first based on pre-stored map table values, providing immediate deceleration response that maintains drivability. As the velocity difference decreases, the system transitions to feedback-dominated control for precise velocity regulation, optimizing both drivability and control precision at different phases.
4Productivity
If the adjustment factor increases with residual distance and velocity difference, then the feed forward torque application is optimized, but the control complexity increases
Solution Approach 1:
The patent changes the adjustment factor parameter based on two key variables: residual distance to the deceleration event and velocity difference. This parameter adaptation optimizes control efficiency by applying appropriate feedforward torque ratios for different driving scenarios without requiring complex control algorithms, as the adjustment factor is determined by straightforward comparisons of these two parameters.
Data Source
AI summary
A method for controlling deceleration of a vehicle includes: controlling a feed forward torque output unit to output feed forward torque stored in a map table, which corresponds to a current velocity of the vehicle and a deceleration target velocity of the vehicle when a deceleration event for the vehicle occurs; outputting feedback torque corresponding to the deceleration target velocity based on a vehicle velocity difference; controlling an adjustment factor output unit to adjust an application ratio of the feed forward torque stored in the map table, which corresponds to the vehicle velocity difference and a residual distance up to the deceleration event; and controlling a final control torque output unit to calculate final control torque for decelerating the vehicle based on the output feed forward torque and feedback torque and the adjusted application ratio and output the calculated final control torque to a powertrain of the vehicle.