Inverse Tyre Model for Low-Latency Wheel Slip Control
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Solution Overview
Problem
Existing vehicle motion management systems in heavy-duty vehicles face performance limitations due to latency and inconsistent actuator and slip control assumptions, leading to sub-optimal wheel slip control and stability issues, particularly in varying operating conditions.
Innovation Solution
Implementing a control unit that utilizes an inverse tyre model to translate wheel force requests into equivalent wheel speed or slip, allowing for closer-to-wheel end control with reduced latency and faster processing, thereby improving stability and maneuverability by adjusting the model based on current operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If torque control is used at the actuator level without consideration towards wheel slip, then the control system is simple to implement, but wheel slip control performance deteriorates and safety functions must intervene
Solution Approach 1:
The system pre-calculates equivalent wheel speed or slip values based on desired wheel forces using an inverse tyre model before actuation occurs. This preliminary transformation of control parameters enables the actuator to directly maintain target wheel slip without requiring complex real-time slip detection and correction, thus improving wheel slip control performance while keeping the control implementation relatively simple.
2Adaptability or versatility
If primary control of the actuator and slip control functions are allocated to different control units, then functional separation is achieved, but communication latencies limit slip control performance
Solution Approach 1:
The patent combines the slip control function with the primary actuator control unit by integrating the inverse tyre model and equivalent wheel speed/slip calculation directly into the actuator control. This merging eliminates the need for communication between separate control units, removing communication latencies and enabling faster, more responsive wheel slip control while maintaining functional separation at the system architecture level.
3Adaptability or versatility
If inconsistent actuator and slip assumptions are made in multiple control units, then distributed control is achieved, but control performance becomes sub-optimal
Solution Approach 1:
The inverse tyre model serves as a universal calculation mechanism that provides consistent equivalent wheel speed or slip values across all control scenarios and operating conditions. By using this single universal approach in the actuator control unit, the system maintains distributed control capability while ensuring consistent and accurate wheel slip control performance across all wheels and situations.
4Ease of operation
If torque requests are sent to wheel torque actuators, then actuator control is straightforward, but response speed to road friction changes is insufficient
Solution Approach 1:
The system changes the control parameter from torque requests to equivalent wheel speed or slip requests. This parameter transformation enables the actuator to directly control wheel slip to match target values, providing much faster response to changes in road friction conditions. The inverse tyre model continuously provides updated equivalent wheel speed/slip values based on desired forces and current conditions, maintaining simple actuator control while dramatically improving response speed.
Data Source
AI summary
A control unit (130, 140) for controlling a heavy duty vehicle (100),wherein the control unit is arranged to obtain input data indicative of a desired wheel force (Fx, Fy) to be generated by at least one wheel (210) of the vehicle (100), andto translate the input data into a respective equivalent wheel speed or wheel slip to be maintained by the wheel (210) to generate the desired wheel force (Fx, Fy) based on an inverse tyre model (f−1) for the wheel (210),wherein the control unit (130, 140) is arranged to obtain the inverse tyre model in dependence of a current operating condition of the wheel (210), andwherein the control unit (130, 140) is arranged to control the heavy duty vehicle (100) based on the equivalent wheel speed or wheel slip.