Steering Controller Torque Adjustment for External Angle Commands

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Solution Overview

Problem

Existing steering controllers that incorporate electric motors for steering steerable wheels face difficulties in adjusting torque based on external angle command values, limiting their ability to assist driving assistance systems effectively.

Innovation Solution

The steering controller executes a series of operation processes, including angle-side operation amount calculation and drive circuit operation, to adjust the electric motor torque according to both steering-side and angle-side operation amounts, allowing for seamless integration of external angle command values and improved controllability of the steering torque.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If feedback control adjusts steering torque to target torque based on steering-side operation amount, then steering feel and controllability are improved, but the ability to respond to external angle command values for driving assistance is limited

Engineering Contradiction:
Improvesteering feelVSAvoidresponse to external angle command values
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent segments the control into two independent paths: steering-side operation amount for feedback control (maintaining steering feel) and angle-side operation amount for external command response (enabling driving assistance). This segmentation allows both functions to operate simultaneously without interference, resolving the contradiction between reliable steering feel and adaptability to external commands.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The control system is designed to handle multiple types of input commands universally. The same actuator and control structure process both driver steering inputs and external angle command values from driving assistance systems, enabling the system to perform multiple functions (steering assistance and automated positioning) without requiring separate dedicated systems.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of operation

If the electric motor operates based on steering-side operation amount for feedback control, then steering controllability is maintained, but integration of driving assistance commands becomes difficult

Engineering Contradiction:
Improvesteering controllabilityVSAvoidintegration of driving assistance
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent merges the steering-side operation amount calculation process and angle-side operation amount calculation process into a unified control architecture. Both operation amounts are calculated and applied to the same actuator through the same feedback control mechanism, simplifying the integration of driving assistance while maintaining steering controllability.

Inventive Principle:
Principle #5Merging (Combining)

3Speed

If angle-side operation amount calculation is added to adjust convertible angle to angle command value, then responsiveness to external commands is improved, but control system complexity increases

Engineering Contradiction:
Improveresponsiveness to external commandsVSAvoidcontrol system structure
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The angle-side operation amount is calculated in advance based on the angle command value from external systems. This preliminary calculation allows the system to be ready to respond immediately when external commands are received, improving responsiveness without adding complex real-time computation during actuation.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3680148B1Steering controller and steering control method
Publication Date: 2023.02.15 JTEKT CORP
  • EP3680148B1 patent drawingFigure 1
  • EP3680148B1 patent drawingFigure 2
  • EP3680148B1 patent drawingFigure 3

AI summary

A steering controller (40) is configured to execute a first operation process for, when an angle command value is not input from outside of the steering controller, calculating a first torque command value corresponding to a steering-side operation amount and operating a drive circuit of an electric motor (32) to adjust torque of the electric motor to the first torque command value. The steering controller (40) is further configured to execute a second operation process for, when the angle command value is input from the outside of the steering controller, calculating a second torque command value corresponding to at least an angle-side operation amount of the steering-side operation amount and the angle-side operation amount and operating the drive circuit of the electric motor (32) to adjust the torque of the electric motor to the second torque command value.