Trailer Stability Control via Lateral Velocity Rate
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Solution Overview
Problem
Existing stability control systems for semi-trailer and center axle trailers are inefficient in detecting unstable drive situations early and require complex data and sensor setups, which can lead to inadequate control and robustness.
Innovation Solution
A method that determines the lateral velocity rate of change using measured or estimated lateral acceleration, trailer velocity, and yaw rate, and initiates controlled brake actuations on specific outer wheels to counteract yaw rate, optimizing brake forces to reduce trailer swing and wear while simplifying sensor requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex data and sensor setups are used for stability control, then detection accuracy improves, but device complexity increases
Solution Approach 1:
The patent extracts and utilizes data already available in the vehicle's existing stability control system (lateral acceleration, yaw rate, longitudinal velocity from standard sensors) rather than adding complex new sensor setups. The method focuses on reprocessing and combining existing sensor data to detect unstable drive situations, thereby avoiding increased device complexity while maintaining detection accuracy.
Solution Approach 2:
The patent makes existing sensors serve multiple functions: the same sensors that provide data for basic stability control also detect unstable drive situations. By making the existing sensor system multi-functional, the patent avoids adding dedicated sensors for unstable drive detection, thus preventing device complexity from increasing while improving detection capability.
2Productivity
If automated brake action is applied to counteract unstable drive situations, then stability control efficiency improves, but brake wear increases
Solution Approach 1:
The patent applies brake force locally and selectively to specific wheels (curve outer wheels) rather than uniformly to all wheels. This localized brake application targets the specific wheels contributing to the unstable drive situation, providing effective stability control while minimizing unnecessary brake wear on other wheels that are not involved in the instability.
Solution Approach 2:
The patent applies partial brake action only to the curve outer wheels that are causing the unstable drive situation, rather than applying full brake force to all wheels. This partial action is sufficient to counteract the specific instability while reducing overall brake wear compared to full-system braking.
3Stability of the object's composition
If brake force is applied to counteract yaw rate, then trailer swing reduction improves, but brake wear increases
Solution Approach 1:
The patent applies brake force locally to specific curve outer wheels rather than uniformly to all wheels. This localized application targets the wheels that are generating the yaw rate and trailer swing, effectively reducing trailer swing while minimizing brake wear on wheels that are not contributing to the instability.
Solution Approach 2:
The patent uses the brake system as a control actuator to generate counteracting yaw moments, effectively copying the function of active yaw control systems but using the existing brake infrastructure. This approach achieves trailer swing reduction without requiring additional dedicated actuators, thereby avoiding increased brake wear from redundant systems.
Data Source
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AI summary
The present invention relates to a method for a stability control of a trailer (1), in particular a semi-trailer (2) or a center axle trailer. According to the inventive method, in a first step a vehicle lateral velocity rate of change v̇ is determined on the basis of v̇ = ay - ur with the lateral acceleration ay, the trailer velocity u and the yaw rate r. The determined vehicle lateral velocity rate of change v̇ is then compared with a threshold T. In the next step of the inventive method in case of the determined vehicle lateral velocity rate of change v̇ exceeding the threshold T a brake actuation of one curve outer wheel (3of) of the trailer (1) is automatically initiated. In particular, the curve outer wheel is activated with a brake force (11of) controlled to equal or be limited to FB,max with FB,max = FL tw / (2d) with the lateral force FL, the track width tw and the longitudinal distance of the wheel from the center of gravity d. The inventive method effectively controls a trailer for increasing the instability of the trailer (1) against trailer swing with reduced brake and tyre wear.