Trailer Stabilization via Steering and Braking Thresholds
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Solution Overview
Problem
Existing trailer stabilization systems fail to effectively address slow-amplitude yaw rate oscillations in vehicle combinations, leading to uncomfortable and potentially unsafe driving conditions, as they often require braking interventions that can be harsh on the driver and vehicle.
Innovation Solution
A method that detects snaking movements in vehicle combinations and implements driver-independent steering interventions by hardening the steering in the direction opposite to yaw rate oscillations, with a control unit managing the steering actuator system to dampen oscillations before resorting to braking, ensuring stabilization without sudden speed reductions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If braking interventions are used to stabilize trailer oscillations, then vehicle stability is improved, but driver comfort deteriorates due to harsh braking
Solution Approach 1:
The stabilization system segments the intervention into two distinct stages based on oscillation amplitude thresholds. The first stage uses steering interventions for low-amplitude oscillations, while the second stage uses braking interventions only for high-amplitude oscillations that exceed the first threshold. This segmentation allows the system to apply the gentler steering correction first, preserving driver comfort while maintaining stability, and only resorts to harsh braking when absolutely necessary.
Solution Approach 2:
The system performs preliminary steering interventions before resorting to braking interventions. When oscillations are detected, the system first attempts to dampen them through steering adjustments alone. Only if the oscillation amplitude grows beyond the first threshold value does the system activate the braking intervention. This preliminary action approach allows stabilization to occur through comfortable steering adjustments in most cases, avoiding harsh braking.
2Ease of operation
If steering interventions are used to dampen oscillations, then driver comfort is improved, but stabilization effectiveness deteriorates for large amplitude oscillations
Solution Approach 1:
The system dynamically adjusts the stabilization strategy based on the real-time amplitude of oscillations. It monitors the oscillation magnitude continuously and transitions from a soft steering-only approach to a more forceful braking intervention when the amplitude exceeds the first threshold. This dynamic adaptation ensures that the system remains comfortable for small oscillations while becoming sufficiently effective for large, dangerous oscillations.
Solution Approach 2:
The system changes the intervention parameter (from steering force to braking force) based on the oscillation amplitude parameter. When the amplitude remains below the first threshold, only steering parameters are adjusted. When the amplitude exceeds the threshold, the system activates braking parameters in addition to steering adjustments. This parameter change allows the system to maintain comfort for minor oscillations while ensuring reliability for severe oscillation events.
3Reliability
If braking interventions are applied early to prevent oscillation growth, then stabilization reliability is improved, but energy consumption increases due to unnecessary speed reduction
Solution Approach 1:
The system uses inexpensive, temporary steering interventions as the first line of defense against oscillations. These steering corrections are applied briefly and locally to dampen small oscillations without causing significant energy loss or speed reduction. Only when these inexpensive steering interventions prove insufficient (amplitude exceeds first threshold) does the system activate the more energy-intensive braking intervention. This approach minimizes energy consumption by using the lighter steering correction for the majority of stabilization events.
Solution Approach 2:
The system applies partial braking intervention only when absolutely necessary, rather than continuously applying full braking to prevent all oscillations. By setting the first threshold relatively high, the system allows small oscillations to occur and be handled by steering alone, applying braking only for the excessive cases that truly threaten stability. This partial action approach avoids the energy waste of continuous or premature braking while maintaining adequate stabilization reliability.
Data Source
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Figure 3
AI summary
A method and a device are provided for stabilizing a vehicle combination made up of a tractor vehicle and a trailer in case of fishtailing motions, in which—the presence of a fishtailing motion of the tractor vehicle is detected,—after the exceeding of a first threshold value by the amplitude of an oscillating fishtailing variable characterizing the fishtailing motion, a driver-independent steering intervention in the steering actuator system of the tractor vehicle takes place and—after the exceeding of a second threshold value by the amplitude of the fishtailing variable, a driver-independent braking intervention in the brake actuator system of the tractor vehicle takes place,—the second threshold value being selected to be greater than the first threshold value.