Trailer Brake Control Using Coupling Force Feedback
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Solution Overview
Problem
Agricultural vehicle-trailer combinations lack effective trailer brake control systems, particularly in situations where the coupling force exceeds safe limits, leading to potential jack-knifing or skidding issues during deceleration.
Innovation Solution
A control system that determines the coupling force between the vehicle and the trailer using parameters already available on the tractor, and generates control signals to manage the trailer brake system, employing primary and secondary control strategies based on the coupling force range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If trailer brake systems are activated to reduce coupling force during deceleration, then vehicle stability is improved and jack-knifing is prevented, but excessive braking can destabilize the vehicle combination by stretching it excessively and applying yaw moment to the towing vehicle
Solution Approach 1:
The control system continuously monitors the coupling force between the towing vehicle and trailer, and adjusts the trailer brake activation accordingly. When coupling force exceeds a threshold during deceleration, the system activates the trailer brakes to reduce the force, while preventing excessive braking that would cause instability. This closed-loop feedback control resolves the contradiction by dynamically balancing brake activation to maintain stability without over-braking.
2Measurement precision
If electronic braking systems with on-board assistant systems (ABS, ESP, ASR, electronic trailer suspension) are used to determine coupling force, then measurement precision is improved, but device complexity and cost increase significantly
Solution Approach 1:
The control system utilizes data already available from the towing vehicle's existing systems (engine control unit, transmission control unit, or hybrid control unit) to determine coupling force. Instead of requiring separate specialized sensors, the system repurposes existing vehicle data (such as engine torque, transmission ratio, vehicle acceleration) to calculate coupling force. This self-service approach resolves the contradiction by achieving adequate measurement precision using already-installed components, avoiding additional complexity and cost.
3Reliability
If trailer brakes are activated to prevent jack-knifing during deceleration, then safety is improved, but the coupling force range becomes more restricted and control becomes more difficult
Solution Approach 1:
The control system activates trailer brakes partially rather than fully, applying just enough braking force to keep the coupling force within the safe operating range. The system monitors coupling force and adjusts brake activation proportionally, using partial brake application to maintain safety while avoiding excessive braking that would complicate control. This resolves the contradiction by achieving safety through measured, proportional action rather than extreme measures.
Data Source
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AI summary
Systems and methods are provided for controlling operation of a trailer brake system associated with an agricultural vehicle-trailer combination. A coupling force between the vehicle and the trailer is determined and used to control operation of the trailer brake system in dependence thereon. A primary control strategy is used in dependence on the determined coupling force being within a coupling force range; and one or more secondary control strategies are used in dependence on the determined coupling force being outside of the coupling force range.