Tractor Brake Control Unit for Vehicle Combination Stability
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Solution Overview
Problem
Existing brake control systems for vehicle combinations struggle to achieve precise braking and stability, especially when the trailer vehicle lacks a separate automatic load-dependent brake force control, leading to inconsistent loading state determination and vehicle dynamics control.
Innovation Solution
The method involves determining the loading states of individual axles and vehicles using available variables, such as axle load distribution and brake-application energy levels, to estimate the weight of tractor and trailer vehicles, allowing for precise control of brake pressures and improved vehicle stability through vehicle dynamics control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If brake pressure levels are determined separately for tractor and trailer vehicles using stored characteristic maps, then braking precision is improved, but device complexity increases due to additional control systems required for the trailer
Solution Approach 1:
The control unit in the tractor vehicle performs multiple functions: it determines the deceleration setpoint value, ascertains the brake-application energy reference value, determines brake pressure setpoint values for both tractor and trailer, and calculates loading states. This multi-functionality eliminates the need for a separate control system in the trailer while maintaining precise braking control for both vehicles.
Solution Approach 2:
The patent combines the brake control functions for both the tractor vehicle and the trailer vehicle into a single control unit located in the tractor. This merging of functions allows the tractor's control unit to manage braking for the entire vehicle combination, reducing overall system complexity while maintaining precise braking control through separate brake pressure determination for each vehicle.
2Stability of the object's composition
If separate automatic load-dependent brake force control is installed on the trailer vehicle, then vehicle stability is improved, but device complexity and cost increase
Solution Approach 1:
The control unit determines the loading state of the trailer vehicle by evaluating the brake-application energy reference value and comparing it with stored characteristic maps. This feedback mechanism provides real-time information about the trailer's loading state, enabling the control unit to adjust brake pressure setpoint values accordingly, thereby maintaining vehicle stability without requiring additional control hardware on the trailer.
Solution Approach 2:
The control unit in the tractor vehicle acts as an intermediary that receives information about the trailer's loading state (through brake-application energy measurements) and translates this into appropriate brake pressure commands for both the tractor and trailer. This intermediary function enables coordinated braking control and maintains vehicle stability without requiring direct control electronics in the trailer.
3Measurement precision
If loading states are determined using additional sensors and measurement devices, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The system uses existing brake control variables (brake-application energy reference value, deceleration setpoint value) that are already available during normal brake operation to determine the loading state. No additional sensors or measurement devices are required - the system repurposes data from the existing brake control system to infer loading conditions, thereby avoiding increased device complexity while maintaining measurement precision.
Solution Approach 2:
The existing brake control system serves dual purposes: it controls braking operations and simultaneously determines the loading state of the trailer vehicle. The brake-application energy reference value, originally used solely for brake pressure control, is also utilized as an indicator of loading state, enabling the system to perform multiple functions without adding dedicated measurement equipment.
Data Source
AI summary
In a method for controlling the brakes of a vehicle combination having a tractor equipped with an electronically controlled brake system, at least one front axle and one rear axle, and a trailer having at least one trailer axle, in the event of a brake actuation, a deceleration setpoint value is ascertained and compared to a deceleration actual value, and a current brake-application energy reference value is ascertained therefrom. Brake-application energy setpoint values for the tractor and trailer are ascertained from the current brake-application energy reference value and brake-application energy levels for the tractor and trailer while using stored characteristic maps, which illustrate the dependencies of the brake-application energy levels on the brake-application energy reference value or on the axle load distribution of the tractor. The characteristic maps are obtained as a function of at least one pre-definable influencing factor. For this, a loading state of the tractor and/or of the trailer and/or the vehicle combination is ascertained.