Motor Vehicle Traction Control Using Slip-Acceleration PID Tuning
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Solution Overview
Problem
Existing traction control systems for single-track motor vehicles, particularly those using PID controllers, face impaired control behavior due to the need for complex adaptation of the D-factor at varying vehicle speeds, which affects the control deviation and drive torque optimization.
Innovation Solution
The method incorporates a PID traction controller that uses a control deviation calculated from setpoint and actual wheel slip, with the D-component determined by slip acceleration derived from wheel and vehicle acceleration differences, allowing for optimized D-factor parameterization independent of vehicle speed through multiplication by the mass moment of inertia, and integrates P, I, and D components with adjustable factors for enhanced control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the D-factor is adapted using a characteristic curve plotted against speed to set the optimum factor for each speed, then the control behavior is optimized across varying speeds, but the device complexity and parameterization effort increase significantly
Solution Approach 1:
The patent changes the parameter basis from vehicle speed to slip acceleration. By defining the D-factor as a function of slip acceleration (dK/dt) rather than vehicle speed, the system achieves speed-independent optimization. The control deviation derivative is calculated as dKerr/dt = dKist/dt - dKsoll/dt, and the D-component becomes MAR,D = kD * dKerr/dt, where kD is a constant determined once based on the mass moment of inertia, eliminating the need for speed-dependent characteristic curves.
2Ease of manufacture
If the D-factor is set to one speed for the PID controller, then the parameterization is simplified, but the control behavior is impaired at other speeds
Solution Approach 1:
The patent transforms the D-factor from a speed-dependent parameter to a slip-acceleration-dependent parameter. The key insight is that slip acceleration (αK = dVAR/dt - dVFZG/dt) directly reflects the dynamic state of wheel slip regardless of vehicle speed. By setting MAR,D = kD * αK where kD = (JAR+Antrieb)/mFZG, the system achieves universal applicability across all speeds while requiring only a single parameter determination based on the mass moment of inertia.
3Productivity
If the D-component is calculated from the gradient of control deviation dependent on vehicle acceleration and wheel acceleration, then the control response is improved, but the determination of excess acceleration becomes complex at varying speeds
Solution Approach 1:
The patent extracts the essential dynamic information from the complex acceleration relationships by focusing solely on slip acceleration. Instead of processing the full vehicle acceleration and wheel acceleration separately and combining them with speed-dependent factors, the system directly calculates αK = dVAR/dt - dVFZG/dt and uses this single parameter to determine the D-component. This extraction simplifies the determination process while maintaining the ability to respond to dynamic changes in wheel slip.
Data Source
AI summary
The present subject matter relates to monitoring traction for a motor vehicle. A vehicle speed and a circumferential speed of the at least one driven wheel are sensed using sensors of the motor vehicle. A control deviation is determined based on a difference of a setpoint wheel slip and an actual wheel slip. The control deviation is input to the PID traction controller. A slip acceleration is determined based on a difference of a wheel acceleration of the at least one driven wheel and a vehicle acceleration determined from the sensed vehicle speed and a circumferential speed of the at least one driven wheel. Using the PID traction controller, a drive torque of the at least one driven wheel is determined from a sum of a P-component, an I-component, and a D-component of the PID traction controller. The drive torque back to the at least one driven wheel.