Vehicle Acceleration Control with Limited Integral Action
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Solution Overview
Problem
The issue of large fluctuations in drive torque due to increased time integrated deviation between target and actual acceleration, leading to deterioration of emission performance, is addressed by suppressing overshoot of actual acceleration relative to target acceleration.
Innovation Solution
A vehicle control device with an integration processing limiting unit that stops the calculation of a time integrated value when certain limiting conditions are met, thereby controlling the torque instruction value to prevent excessive acceleration changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If integral control is performed using time integrated value of acceleration deviation, then steady deviation between target acceleration and actual acceleration is eliminated, but overshoot of actual acceleration occurs and drive torque fluctuates
Solution Approach 1:
The patent dynamically adjusts the integral gain based on the vehicle's current operating state (acceleration state, engine load, etc.). When the vehicle is in a state prone to overshoot, the integral gain is reduced or integral control is suspended, preventing torque fluctuations. When the vehicle is in a stable state, normal integral control is applied to eliminate steady deviation, thus resolving the contradiction between control precision and stability.
Solution Approach 2:
The patent changes the integral gain parameter according to different operating conditions. By monitoring parameters such as acceleration state and engine load, the system adjusts the integral gain to appropriate values, preventing overshoot while maintaining effective elimination of steady deviation, thereby balancing control precision and torque stability.
2Measurement precision
If time integrated value calculation is continuously performed, then control accuracy is improved, but calculation complexity and processing load increase
Solution Approach 1:
Instead of continuously performing integral control calculations, the patent implements periodic suspension of integral control based on detected operating conditions. When overshoot risk is detected, integral control is temporarily suspended, reducing calculation load while maintaining control accuracy during normal operation, thus resolving the contradiction between precision and complexity.
3Speed
If integral gain is increased to eliminate steady deviation faster, then response speed improves, but overshoot and drive torque fluctuation worsen
Solution Approach 1:
The patent dynamically adjusts the integral gain based on real-time detection of vehicle operating state. When the vehicle is in a state that can tolerate faster response, higher integral gain is applied to eliminate deviation quickly. When the vehicle is in a state prone to overshoot, the integral gain is reduced, preventing torque fluctuations. This dynamic adjustment resolves the contradiction between response speed and stability.
Data Source
AI summary
An overshoot of actual acceleration relative to target acceleration is suppressed in controlling acceleration of a vehicle by performing integral control. A vehicle control device includes: an actual acceleration recognition unit that recognizes actual acceleration of a vehicle; an integrated value calculation unit that calculates a time integrated value of a difference between predetermined target acceleration and the actual acceleration; a control instruction value setting unit that sets a control instruction value for a drive apparatus of the vehicle based on the time integrated value; and an integration processing limiting unit that limits calculation of the time integrated value performed by the integrated value calculation unit so that the time integrated value when a predetermined limiting condition is satisfied is smaller than that when the limiting condition is not satisfied.