Adaptive Filter Traction Control Phase Offset
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Solution Overview
Problem
Traction control systems experience performance losses on level asphalt due to phase offset in the regulating circuit caused by slip filtering, especially during wheel load fluctuations.
Innovation Solution
An adaptive filter determines a filtered actual slip by incorporating additional variables such as wheel load fluctuations and vertical acceleration, which is then used by a PID controller to set engine torque, thereby avoiding performance losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a filter is used to determine filtered actual slip from actual slip, then strong oscillations in engine torque are prevented during wheel load fluctuations, but phase offset occurs in the regulating circuit on level asphalt causing performance losses
Solution Approach 1:
The patent applies a dynamic filter whose cutoff frequency is adaptively adjusted based on detected wheel load fluctuations. When wheel load fluctuations are detected, the cutoff frequency is reduced to strengthen filtering and prevent torque oscillations. When no fluctuations are detected, the cutoff frequency is increased to minimize phase offset and performance losses on level asphalt.
Solution Approach 2:
The invention changes the parameter of the filter's cutoff frequency based on operating conditions. By detecting wheel load fluctuations and adjusting the cutoff frequency accordingly, the system optimizes the balance between preventing torque oscillations during load changes and minimizing phase offset during steady-state operation on level surfaces.
2Stability of the object's composition
If the cutoff frequency of the filter is reduced to prevent oscillations during wheel load fluctuations, then engine torque stability is improved, but performance losses occur on level asphalt due to increased phase offset
Solution Approach 1:
The system dynamically adjusts the filter's cutoff frequency based on real-time detection of wheel load fluctuations. During wheel load fluctuations, the cutoff frequency is reduced to maintain torque stability. During normal operation on level asphalt, the cutoff frequency is increased to minimize phase offset and maintain optimal traction control performance.
Solution Approach 2:
The invention implements parameter changes by adjusting the cutoff frequency of the filter according to operating conditions. This adaptive parameter adjustment allows the system to optimize both torque stability during load fluctuations and performance on level surfaces, avoiding the need to permanently compromise either aspect.
Data Source
AI summary
A traction control method and device for a vehicle is disclosed. In the method, an actual slip of a wheel of the vehicle is made available, a filtered actual slip is determined adaptively from the actual slip by an adaptive filter, the filtered actual slip is passed on to a controller, and the engine torque is set by the controller as a function of the filtered actual slip and of a target slip.