Active Suspension Control for Trailer Hitch Angle Stability

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Solution Overview

Problem

Existing vehicle control systems fail to effectively stabilize the cornering of vehicles towing trailers, as they do not adequately address trailer sway and hitch angle dynamics, leading to instability during turns and maneuvers.

Innovation Solution

A trailer sway control system that includes active suspension actuators and electric motors, controlled by a module that adjusts vertical forces and torque outputs based on the hitch angle, yaw rate, and steering angle to minimize differences between actual and reference angles and rates, thereby enhancing stability and reducing trailer sway.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If existing vehicle control systems are used, then the system complexity remains low, but the trailer sway and cornering stability deteriorate

Engineering Contradiction:
Improvetrailer sway stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The control system continuously monitors the hitch angle between the trailer and vehicle, compares it to a desired reference angle, and adjusts suspension actuator forces based on the error signal. This closed-loop feedback mechanism dynamically stabilizes the trailer sway while maintaining manageable system complexity through proportional control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system uses the vehicle's existing suspension actuators to perform dual functions: maintaining ride comfort and stabilizing trailer sway. By leveraging already-present active suspension components, the system achieves enhanced stability without adding separate dedicated sway control hardware.

Inventive Principle:
Principle #25Self-service

2Stability of the object's composition

If active suspension actuators are used to control hitch angle, then the cornering stability improves, but the use of energy increases

Engineering Contradiction:
Improvecornering stabilityVSAvoidenergy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The control system operates in discrete control cycles, adjusting suspension actuator forces periodically based on current hitch angle measurements. This periodic control approach maintains cornering stability while allowing energy-saving modes between adjustment cycles when the system is already in a stable state.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system dynamically adjusts the reference hitch angle parameter based on vehicle operating conditions such as steering angle and speed. By adapting control parameters to current conditions rather than maintaining fixed setpoints, the system achieves consistent cornering stability across varying scenarios while minimizing unnecessary energy consumption from constant adjustments.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If the control system adjusts vertical forces based on hitch angle, then the trailer sway reduces, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvetrailer swayVSAvoidactuator force precision
Core Design Contradiction:
Object-affected harmful factorsVSManufacturing precision

Solution Approach 1:

The control system introduces an intermediary reference hitch angle parameter that translates driver intent and vehicle state into desired trailer positioning. This intermediate variable serves as a buffer, allowing the system to achieve smooth trailer sway reduction through progressive adjustments rather than requiring precise direct control of actuator forces.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system applies suspension actuator forces that may exceed the minimum required for sway reduction, using available actuator capacity to provide robust stabilization. This approach compensates for uncertainties in the mechanical system and achieves reliable trailer sway reduction without requiring extremely precise force control, as long as the actuator can provide sufficient corrective force when needed.

Inventive Principle:
Principle #16Partial or excessive action

Data Source

PatentEP4306342A1Vehicle control systems and methods based on trailer hitch angle
Publication Date: 2024.01.17 ADVANCED SUSPENSION TECHNOLOGY LLC
  • EP4306342A1 patent drawingFigure 1
  • EP4306342A1 patent drawingFigure 2
  • EP4306342A1 patent drawingFigure 3

AI summary

A trailer sway control system for a vehicle includes: a front left active suspension actuator; a front right active suspension actuator; a rear left active suspension actuator; a rear right active suspension actuator; an actuator control module configured to: based on a hitch angle between (a) a first longitudinal axis of a trailer hitched to the vehicle and (b) a second longitudinal axis of the vehicle, determine target vertical forces for the front left active suspension actuator, the front right active suspension actuator, the rear left active suspension actuator, and the rear right active suspension actuator, respectively; and selectively adjust the front left active suspension actuator, the front right active suspension actuator, the rear left active suspension actuator, and the rear right active suspension actuator based on the target vertical forces, respectively.