Vehicle Running Control Apparatus Speed Follow-Up Stability
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Solution Overview
Problem
Automatic running control systems for vehicles face challenges in maintaining target vehicle speed during interruptive control scenarios, leading to sudden changes in driving force or torque, which can disrupt vehicle behavior and delay speed recovery.
Innovation Solution
A running control apparatus that calculates the difference between target and actual vehicle speeds, decides the required driving output based on an integrated value, and imposes limits on the increase or decrease of driving force or torque to prevent sudden changes, ensuring smooth transition back to target speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the required driving force or torque is adjusted based on the integrated value of the speed difference to ensure good follow-up performance, then the vehicle speed can swiftly follow the target speed, but sudden changes in driving force or torque occur when interruptive control is active, causing vehicle behavior disruption
Solution Approach 1:
The determination unit detects before the integrated value becomes excessively large whether interruptive control is active, and if so, prevents the integration from continuing unchecked. This preliminary detection and prevention mechanism avoids the harmful effect of sudden driving force changes while maintaining the benefit of swift speed follow-up during normal operation
Solution Approach 2:
The determination unit acts as an intermediary between the integrated value calculation and the driving force adjustment. It monitors the integration process and intervenes when interruptive control is detected, preventing the harmful transmission of excessive integrated values to the driving force control while allowing normal integration to proceed during non-interruptive periods
2Speed
If the feedback gain is increased to improve responsiveness of vehicle speed to target speed, then the follow-up performance improves, but the vehicle speed tends to overshoot the target speed
Solution Approach 1:
The system dynamically adjusts the effective feedback gain by selectively enabling or disabling integration based on interruptive control detection. During interruptive control, integration is prevented (effectively reducing gain), while during normal operation, full integration is applied (maintaining high gain for responsiveness). This dynamic adjustment allows the system to achieve both responsiveness and stability under different operating conditions
Solution Approach 2:
The system changes the parameter of integration accumulation based on the detection of interruptive control. When interruptive control is active, the integration parameter is held constant rather than continuously accumulated, effectively changing the feedback characteristic from high-gain to low-gain mode to prevent overshoot while maintaining responsiveness during normal operation
Data Source
AI summary
A running control apparatus for a vehicle includes a required driving output deciding unit that decides a required driving force of a driving system of the vehicle on the basis of an integrated value of a difference between a target vehicle speed and an actual vehicle speed, a driving control unit that controls the actuation of the driving system on the basis of the required driving force, and a determination unit that determines whether or not the required driving force is unrealizable in the control of the driving system due to the intervention of additional control. The required driving output deciding unit imposes a limit on an increase or a decrease in the required driving force when the determination unit determines that the required driving force is unrealizable in the control of the driving system.