Articulated Vehicle Virtual Steering Angle Control

Solution Overview

Problem

Existing control devices for articulated vehicles rely on the yaw rate of the tractor, which may be inappropriate when the tractor is stopped, leading to inaccuracies in calculating variables for trailer control, especially when the trailer is displaced.

Innovation Solution

A computation device for articulated vehicles that performs curvature variable acquisition, trailer length variable acquisition, and virtual steering angle calculation using the trailer's yaw rate and length to determine the displacement direction between the trailer and tractor, independent of the tractor's yaw rate.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If the yaw rate of the tractor is used to calculate variables for trailer control, then the control system is simple to implement, but the calculation accuracy deteriorates when the tractor is stopped

Engineering Contradiction:

Improvecontrol system complexityVSAvoidcalculation accuracy of trailer control variables

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent segments the control system into two independent parts: using the trailer's yaw rate specifically for calculating the virtual steering angle, while the tractor's yaw rate is used for other control variables. This segmentation allows the virtual steering angle calculation to maintain high accuracy even when the tractor is stopped, as it no longer depends on the tractor's motion state.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces the virtual steering angle as an intermediary parameter that is calculated using the trailer's yaw rate. This intermediary then serves as the basis for controlling the trailer's movement, eliminating the need to directly use the tractor's yaw rate for this specific calculation and thus resolving the accuracy issue when the tractor is stationary.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the tractor is stopped to avoid obstacles, then the tractor can navigate difficult terrain, but the trailer control accuracy deteriorates due to inappropriate use of tractor yaw rate

Engineering Contradiction:

Improveterrain adaptabilityVSAvoidtrailer control variable accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent segments the control system into two independent parts: using the trailer's yaw rate specifically for calculating the virtual steering angle, while the tractor's yaw rate is used for other control variables. This segmentation allows the virtual steering angle calculation to maintain high accuracy even when the tractor is stopped, as it no longer depends on the tractor's motion state.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic adaptability by switching the data source for virtual steering angle calculation based on the operational context. When the tractor is stopped, the system dynamically uses the trailer's yaw rate instead of the tractor's yaw rate, allowing the system to adapt to different terrain conditions while maintaining control accuracy.

Inventive Principle:

Principle #15Dynamics

3Measurement precision

If the trailer's yaw rate is used to calculate the virtual steering angle, then the calculation accuracy is improved when the tractor is stopped, but the system complexity increases

Engineering Contradiction:

Improvevirtual steering angle accuracyVSAvoidcontrol system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces the virtual steering angle as an intermediary parameter that is calculated using the trailer's yaw rate. This intermediary then serves as the basis for controlling the trailer's movement, eliminating the need to directly use the tractor's yaw rate for this specific calculation and thus resolving the accuracy issue when the tractor is stationary.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent makes the control system multi-functional by enabling it to use different data sources (tractor yaw rate or trailer yaw rate) depending on the operational context. The virtual steering angle calculation module can universally accept input from either source, making the system adaptable to both moving and stopped tractor conditions without requiring completely separate control paths.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentEP4640524A1Computation device for articulated vehicle, control device for articulated vehicle, computation method for articulated vehicle, and computation program for articulated vehicle

Publication Date: 2025.10.29 JTEKT CORP

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AI summary

An articulated vehicle includes a tractor and a trailer that is towed by the tractor. A computation device (50) of the articulated vehicle is configured to execute curvature variable acquisition processing, trailer length variable acquisition processing, and virtual steering angle calculation processing. The curvature variable acquisition processing is processing of acquiring a value of a curvature variable. The curvature variable is a variable indicating a curvature of a path of travel of the trailer. The trailer length variable acquisition processing is processing of acquiring a value of a trailer length variable. The trailer length variable is a variable indicating a length of the trailer. The virtual steering angle calculation processing is processing of calculating a virtual steering angle using the value of the curvature variable and the value of the trailer length variable as inputs. The virtual steering angle is an angle indicating a displacement direction of a linking point between the trailer and the tractor.