Velocity-Adaptive Trailer Brake Controller for Torque Consistency
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Solution Overview
Problem
Existing trailer brake systems experience reduced effectiveness at higher vehicle speeds and increased 'brake-grab' at low speeds due to the mechanics of electrically actuated dual-servo drum brakes, and they fail to accurately calculate vehicle speed under various conditions, leading to inconsistent braking performance.
Innovation Solution
A trailer brake controller that adjusts its output based on vehicle velocity to compensate for the loss of brake torque at higher speeds and reduce brake-grab at low speeds, using a correction factor calculated from the effective baseline output profile and vehicle speed, and improves speed estimation by considering dynamic wheel speed data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed gain brake controller output profile is used, then the system is simple to operate, but brake torque effectiveness decreases at higher vehicle speeds
Solution Approach 1:
The brake controller dynamically adjusts the brake control signal based on detected vehicle speed. The system transitions from a fixed gain approach to a dynamic control strategy where the brake control signal varies with vehicle speed, ensuring consistent brake torque effectiveness across different speed ranges while maintaining ease of operation through automatic adjustment.
Solution Approach 2:
The system changes the brake control signal parameter based on vehicle speed detection. At different speed ranges, the controller modifies the electrical output signal characteristics to compensate for the reduced effectiveness of dual-servo drum brakes at higher speeds, thereby maintaining reliable brake torque across the entire operating range.
2Device complexity
If a fixed gain brake controller output profile is used, then the device complexity is low, but braking performance consistency across speed ranges deteriorates
Solution Approach 1:
The brake controller incorporates feedback from vehicle speed detection to automatically adjust the brake control signal. The system detects current vehicle speed and uses this information to modify the electrical output signal, creating a closed-loop control system that maintains consistent braking performance across different speed ranges without requiring complex manual adjustment mechanisms.
Solution Approach 2:
The brake controller performs self-adjustment based on detected vehicle speed conditions. The system automatically modifies its own output characteristics in response to speed changes, eliminating the need for external intervention or complex mechanical adjustment mechanisms while maintaining consistent braking performance across varying operating conditions.
3Ease of operation
If wheel speed is used to calculate vehicle velocity, then the measurement is simple to obtain, but accuracy deteriorates during rapid deceleration or acceleration
Solution Approach 1:
The system applies asymmetric weighting or selection logic when multiple wheel speed sensors are available. During rapid deceleration or acceleration events, the controller selectively uses data from wheels that are not experiencing extreme slip conditions, applying different selection criteria based on the detected maneuver type to maintain velocity measurement accuracy while keeping the system simple to obtain data.
Solution Approach 2:
The system preemptively identifies conditions that would lead to inaccurate velocity measurements (such as rapid deceleration or acceleration) and adjusts its measurement strategy in advance. By detecting these conditions and switching to alternative measurement approaches before the error occurs, the system maintains accuracy without adding complex real-time correction mechanisms.
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 system maintains consistent brake torque across a range of vehicle speeds, reducing brake-grab at low speeds and enhancing overall braking performance and safety by accurately accounting for vehicle velocity and wheel dynamics.
Implementation Method 1
The trailer is commonly equipped with electrically actuated trailer brakes. The controller utilizes a brake input signal in combination with the user set gain to generate a brake control signal... This control signal is sent to the electrically actuated brakes which are thereby utilized to effectuate braking within the trailer.
Implementation Method 2
At increased velocities, it is known that the effectiveness of dual-servo brake torque is reduced... an applied brake torque may result in the brakes locking up (also known as 'grabbiness') rather than incrementally applying braking friction.
Data Source
AI summary
A method of controlling a trailer brake system using a trailer brake controller positioned within a passenger vehicle is provided. The method includes obtaining intended braking inputs and developing an effective baseline trailer brake controller output profile based thereon. The method scales the effective baseline trailer brake controller output profile in response to an adjustable gain setting set by an operator. A vehicle velocity is obtained and used to calculate a correction factor to the effective baseline trailer brake controller output profile. The effective baseline trailer brake controller output profile is then adjusted using the correction factor to generate a corrected trailer brake controller output signal.