Adaptive PID Control Gain for Vehicle Driving Force Stability
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Solution Overview
Problem
Conventional driving force control systems struggle to maintain stable control on both flat and inclined roads, leading to vehicle speed fluctuations due to inappropriate control gains when transitioning from flat to inclined surfaces.
Innovation Solution
A driving force control apparatus that adjusts control gains based on road inclination, using a PID control formula with varying proportional gains to ensure stable driving force restricting control, and detects specific driver operations to limit driving force generation, preventing sudden vehicle acceleration or movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed control gain is used in feedback control for driving force restricting, then the control is simple to implement, but the vehicle speed fluctuates greatly on inclined roads
Solution Approach 1:
The control gain is made dynamic by adjusting it according to the detected road gradient. The control unit changes the control gain value based on the gradient magnitude, transitioning from a fixed gain system to an adaptive dynamic gain system that responds to road conditions, thereby stabilizing vehicle speed on inclined roads.
Solution Approach 2:
The control parameter (control gain) is changed based on the road gradient parameter. When the gradient exceeds a threshold, the control unit selects a different control gain value, effectively adapting the control system to the current road condition and preventing excessive vehicle speed fluctuations.
2Speed
If the control gain is increased to improve response on flat roads, then the driving force restriction is more effective, but the vehicle speed fluctuates excessively on inclined roads
Solution Approach 1:
Different control gain values are applied for different road conditions (flat vs. inclined). The control unit selects appropriate control gain values based on the detected gradient, applying locally optimized control parameters for each situation rather than a single global parameter.
Solution Approach 2:
The control gain parameter is varied according to the road gradient condition. The control unit changes the control gain value when transitioning from flat to inclined roads, optimizing the control effectiveness for each specific condition and preventing speed fluctuations.
3Stability of the object's composition
If the control gain is decreased to stabilize vehicle speed on inclined roads, then the speed fluctuation is reduced, but the driving force restriction effectiveness is diminished
Solution Approach 1:
The control system dynamically adjusts the control gain based on real-time road gradient detection. This dynamic adaptation allows the system to maintain high effectiveness on flat roads while ensuring stability on inclined roads, resolving the trade-off between the two requirements.
Solution Approach 2:
The control gain parameter is changed conditionally based on the road gradient. The control unit selects different parameter values for different operating conditions, ensuring both effectiveness and stability are optimized for the current road situation.
Data Source
AI summary
The driving force ECU calculates a restricted driving force for a driving force restricting control, by using a Proportional-Integral-Differential control formula which utilizes a difference between a target acceleration varied depending on a vehicle speed and an actual acceleration of the vehicle. The driving force ECU adjusts (changes) a proportion gain K1 of the Proportional-Integral-Differential control formula based on an inclination angle θ of a road in such a manner that a value of the proportion gain K1 used when the inclination inclination angle θ is relatively large is smaller than a value of the proportion gain K1 used when the inclination inclination angle θ is relatively small. The driving force ECU performs a driving force restricting control by selecting, as a target driving force used for the driving force restricting control, a pedal required driving force or the restricted driving force, whichever is smaller.