Joystick Steering Sensitivity Control for Fine Wheel Angle Adjustment
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Solution Overview
Problem
When a joystick is used as an operating member in a steer-by-wire steering system, the large change in steered angle relative to the amount of operation makes fine adjustments difficult.
Innovation Solution
A steering control device with a target steering corresponding value computing unit that determines low sensitivity conditions and adjusts the amount of change in steered angle based on the operation of an operating lever, using low sensitivity computation processing when necessary, and normal computation processing otherwise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the driver operates the steering wheel without support, then the driver can maintain alertness through physical effort, but the driver experiences arm fatigue and discomfort over time
Solution Approach 1:
The patent introduces an intermediary device (steering wheel support mechanism) between the driver's arms and the steering wheel. This support provides physical assistance to hold the steering wheel, reducing the burden on the driver's arms while maintaining the connection needed for alertness and control.
Solution Approach 2:
The support mechanism is designed to automatically adjust and adapt to the driver's needs without requiring continuous manual intervention. The system self-regulates the support force and positioning based on detected driver state and steering wheel position, providing ongoing assistance without adding operational complexity.
2Object-affected harmful factors
If a steering wheel support device is added to assist the driver, then arm fatigue is reduced, but the device complexity increases
Solution Approach 1:
The steering wheel support device is integrated with existing steering control functions, allowing it to serve multiple purposes: providing physical support to reduce fatigue, maintaining steering wheel position, and working cooperatively with the driver's natural steering inputs. This multi-functionality reduces the need for separate dedicated components.
Solution Approach 2:
The support mechanism dynamically adjusts its operational parameters (support force magnitude, positioning, stiffness) based on real-time conditions such as driver input, vehicle state, and detected fatigue levels. This adaptability allows the system to provide optimal support with minimal fixed infrastructure.
3Ease of operation
If the support device actively assists steering operations, then driver effort is reduced, but the natural steering feel and direct control are compromised
Solution Approach 1:
The support device incorporates feedback mechanisms that continuously monitor driver steering inputs, vehicle dynamics, and road conditions. This feedback allows the support system to adjust its assistance level in real-time, providing support when needed while preserving the driver's natural steering feel and direct control authority.
Solution Approach 2:
The support mechanism transitions from a static fixed-position support to a dynamic system that can adjust its support characteristics based on operational conditions. The support force and positioning change dynamically to match the driver's steering intentions and vehicle state, maintaining natural steering feel while reducing effort.
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A steering control device (1) includes a target steering corresponding value computing unit configured to compute a target steering corresponding value that is a target value of a convertible value that can be converted into a steered angle (θi) of steered wheels (3), and a control signal generating unit configured to generate a control signal for actuation of a steering unit (5), based on the target steering corresponding value. The target steering corresponding value computing unit is configured to execute low sensitivity determination processing for determining whether or not a low sensitivity condition for reducing an amount of change in the steered angle (θi) with respect to an amount of change in an amount of operation (θl) of an operating lever (11) is satisfied, normal computation processing for computing the target steering corresponding value based on the amount of operation when the low sensitivity condition is not satisfied, and low sensitivity computation processing for computing, based on the amount of operation, the target steering corresponding value having a smaller absolute value than the target steering corresponding value computed by the normal computation processing, when the low sensitivity condition is satisfied.