Multi-Link Vehicle Steering Apparatus with Adjustable Kingpin Axis
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Solution Overview
Problem
Conventional vehicle steering apparatuses fail to achieve a large turning angle and provide stable steering feeling due to insufficient arm length and unclear correlation between steering operation amount and turning angle, as well as arbitrary positioning of the imaginary kingpin axis.
Innovation Solution
A vehicle steering apparatus with left and right arm mechanisms connected via front and rear arms with plural links, an arm driving device to adjust link angles, an imaginary kingpin axis setting device, and a turning angle control device to maintain a stable correlation between steering operation amount and turning angle, allowing for adjustable imaginary kingpin axis positioning and geometry changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the arm length is increased to achieve a larger turning angle, then the turning angle is improved, but the device complexity and structural space requirements increase
Solution Approach 1:
The front and rear arms are divided into multiple links (front arm includes front upper link and front lower link; rear arm includes rear upper link and rear lower link) that can rotate relative to each other. This segmentation allows the arm mechanism to achieve extended effective length and larger turning angles while maintaining a compact folded structure when not in use, thus resolving the contradiction between arm length and device complexity
Solution Approach 2:
The arm mechanism transitions from a fixed single-link structure to a dynamic multi-link structure with variable configuration. The links can rotate and extend dynamically during steering operations to achieve larger turning angles, then fold back to a compact position when steering is complete, effectively managing both arm length requirements and structural space constraints
2Reliability
If the correlation between steering operation amount and turning angle is made adjustable for different imaginary kingpin axis positions, then the steering feeling stability is improved, but the control system complexity increases
Solution Approach 1:
The control device adjusts the correlation parameters between steering operation amount and turning angle based on the selected imaginary kingpin axis position. Different correlation characteristics (including linear and non-linear relationships) are applied depending on whether the imaginary kingpin axis is positioned at the front end, rear end, or center of the vehicle wheel, ensuring stable steering feeling while managing control complexity through parameter-based adaptation
3Adaptability or versatility
If the imaginary kingpin axis position is set arbitrarily to optimize steering performance, then the steering adaptability is improved, but the manufacturing and setup precision requirements increase
Solution Approach 1:
The imaginary kingpin axis position is made dynamically adjustable through the link angle control mechanism. The system can switch between different imaginary kingpin axis positions (front end, rear end, center) based on driving conditions, providing steering adaptability without requiring precise physical manufacturing of different axis positions. The virtual axis position is determined by control parameters rather than physical hardware precision
Data Source
AI summary
There are provided left and right arm mechanisms that connect an arm attachment portion as a part of a vehicle body to vehicle wheel attachment portions attached with front wheels via a front arm and a rear arm disposed in a front-rear direction of a vehicle and having plural links; and servo motors that independently drive the left and right arm mechanisms so that each link angle corresponding to a turning angle is determined. The setting position of the imaginary kingpin axis may be changed. Each link angle changes within a range of maintaining a correlation in which the turning angle increases in accordance with an increase in the steering operation amount when controlling the servo motors so as to obtain the turning angle corresponding to the steering operation amount of a steering wheel.