Trailer Brake Controller Standstill Torque Transition
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Solution Overview
Problem
Conventional trailer brake controllers provide insufficient brake torque at standstill, leading to instability when the tow vehicle/trailer combination is stationary, especially on inclined surfaces, due to speed-dependent brake-actuating output signals.
Innovation Solution
A trailer brake controller that transitions from a speed-dependent zero-velocity output signal to a trailer hold zero-velocity output signal, increasing brake torque when the vehicle is at a standstill and the brake system is in a torque-providing state, ensuring maximum brake torque is applied to maintain the tow vehicle/trailer combination at a standstill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a speed-dependent brake-actuating output signal is used to reduce grabbiness at low speeds, then braking smoothness is improved, but brake torque at standstill is reduced
Solution Approach 1:
The brake controller dynamically adjusts the brake-actuating output signal based on vehicle speed and brake demand. At low speeds, it reduces output to prevent grabbiness, while at standstill it transitions to a different control mode that increases output to provide sufficient holding torque. This dynamic adaptation resolves the contradiction by optimizing the signal characteristics for each operating condition.
Solution Approach 2:
The system changes the parameters of the brake-actuating output signal based on operating conditions. Specifically, it transitions from a speed-dependent signal with reduced amplitude at low speeds to a standstill-specific signal with increased amplitude. This parameter change allows the system to achieve both smooth braking at low speeds and adequate holding torque at standstill.
2Ease of operation
If conventional trailer brake controllers are used with speed-dependent output signals, then braking at low speeds is smoother, but stability at standstill is reduced
Solution Approach 1:
The brake controller implements dynamic control that adapts to the vehicle's operational state. When the vehicle is moving at low speeds, it uses speed-dependent signals for smooth braking. When the vehicle reaches standstill, it dynamically transitions to a hold mode that applies increased brake torque to maintain stability, thus resolving the stability issue without compromising low-speed braking smoothness.
Solution Approach 2:
The system uses feedback from vehicle speed sensors and brake demand signals to determine the appropriate brake-actuating output. At standstill, the feedback mechanism detects the stationary condition and triggers an increased output signal to maintain stability, while during low-speed movement, it feedback-based reduction prevents grabbiness.
3Force
If maximum brake torque is applied at standstill, then holding capability is improved, but risk of brake locking increases
Solution Approach 1:
The system applies different quality characteristics to the brake control signal based on the operational phase. At standstill, it applies a localized increase in signal amplitude specifically for holding, while during movement it maintains speed-dependent modulation. This localized differentiation provides maximum holding capability without the risk of brake locking during dynamic operation.
Solution Approach 2:
The brake controller changes the parameters of the output signal based on vehicle state. During movement, it uses speed-dependent parameter modulation to prevent locking, while at standstill it transitions to a parameter set that maximizes holding torque. This parameter adaptation resolves the contradiction between holding capability and locking risk.
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
This solution enhances the ability of the trailer brake system to maintain the tow vehicle/trailer combination at a standstill by increasing brake torque, overcoming the limitations of conventional systems that result in reduced brake torque at low speeds.
Implementation Method 1
electrically actuated trailer brakes... A driver of the tow vehicle sets the gain on the trailer brake controller, where the gain dictates how much electrical output is generated by the trailer brake controller... This control signal is sent to the trailer brake system via a wiring harness and is utilized by the trailer brake system to effectuate braking by the electrically actuated trailer brakes of the trailer brake system
Implementation Method 2
an applied brake torque can result in the brakes locking up... incrementally applying braking friction... the trailer brake system to effectuate braking by the electrically actuated trailer brakes... subsequently generates a braking torque on the trailer wheels
Data Source
AI summary
A vehicle comprises a speed-sensing device outputting a signal indicating a velocity of the vehicle, a brake system outputting a signal for indicating when the brake system is being commanded to a brake torque providing state, and a trailer brake controller coupled to the speed-sensing device and the brake system. The trailer brake controller utilizes the signal of the speed-sensing device to determine when the vehicle is in a zero-velocity state and utilizes the signal of the brake system to determine when the brake system is being commanded to the brake torque providing state. The trailer brake controller transitions a brake-actuating output signal thereof from a speed-dependent zero-velocity output signal value to a trailer hold zero-velocity output signal value greater than the speed-dependent zero-velocity output signal value when it is determined that the brake system is in the brake torque providing state while the vehicle is in the zero-velocity state.