Tractor Braking Force Threshold for Jack-Knife Prevention
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Solution Overview
Problem
Braking a vehicle combination by operating only the tractor brake assembly increases the risk of jack-knifing or swinging out of the trailer, as existing methods lack accurate determination of the tractor longitudinal force threshold for safe braking.
Innovation Solution
A method to determine a tractor longitudinal force threshold value by calculating trailer lateral forces, considering trailer mass, inclination angles, articulation angles, and horizontal friction forces, enhancing accuracy and safety in braking the vehicle combination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If only the tractor brake assembly is operated for braking the vehicle combination, then regenerative braking energy can be maximized and the trailer brake assembly can be kept inactive for cooling, but the risk of jack-knifing or swinging out of the trailer increases
Solution Approach 1:
The system dynamically adjusts the braking force parameter by determining a threshold value based on multiple variables including trailer lateral force, articulation angle, longitudinal gravity force, and horizontal friction force. When the calculated tractor longitudinal force remains below the threshold, regenerative braking is permitted; otherwise, service braking is activated to prevent jack-knifing
Solution Approach 2:
The system continuously monitors critical parameters such as articulation angle, trailer lateral force, and longitudinal gravity force, and uses this feedback to dynamically adjust the braking strategy. The feedback loop ensures that if conditions approach unsafe thresholds, the control system transitions from regenerative to service braking to maintain stability
2Device complexity
If the tractor longitudinal force threshold is determined without considering longitudinal gravity force, then the determination procedure is simpler, but the accuracy of the threshold determination is reduced
Solution Approach 1:
The determination procedure is segmented into distinct computational steps: obtaining trailer mass, calculating longitudinal gravity force from mass and inclination angle, determining trailer lateral force from gravity force and articulation angle, calculating horizontal friction force, and finally synthesizing these into the threshold value. This segmentation makes the complex procedure systematic and manageable
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method provides accurate determination of the tractor longitudinal force threshold, enabling safe braking of the vehicle combination with reduced risk of undesired conditions like jack-knifing.
Implementation Method 1
determining a longitudinal gravity force value indicative of a longitudinal gravity force, in the trailer longitudinal direction, imparted on the trailer on the basis of at least the trailer mass value and the longitudinal trailer inclination angle value
Implementation Method 2
determining a horizontal friction force value indicative of a possible total horizontal frictional force obtainable between the ground supporting the tractor and ground engaging members of the tractor
Data Source
AI summary
The present disclosure relates to a method for determining a tractor longitudinal force threshold(FLTRret,threshold)for a tractor longitudinal retardation force(FLTRret)that can be imparted on a tractor of a vehicle combination including the tractor and a trailer for retarding the vehicle combination. The trailer has a trailer longitudinal extension in a trailer longitudinal direction (LTL), a trailer lateral extension in a trailer lateral direction (TTL) and a trailer vertical extension in a trailer vertical direction (VTL), and the tractor has a tractor longitudinal extension in a tractor longitudinal direction (LTR), a tractor lateral extension in a tractor lateral direction (TTR) and a tractor vertical extension in a tractor vertical direction (VTR ), wherein the tractor longitudinal retardation force(FLTRret)extends in a direction parallel to a tractor longitudinal direction (TTR).