Fluid Flow Control Mechanism for Steering Wheel Torque Locking
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Solution Overview
Problem
Steer-by-wire assemblies lack effective mechanisms for providing variable mechanical end stops, locking the steering wheel, and achieving desired steering torque, especially when the steering wheel emulator fails or is not in use.
Innovation Solution
A pneumatic/hydraulic fluid-flow control mechanism with a housing, flow control valves, a shaft, piston, and springs that adjust torque on the steering column, coupled with a reduction-gear set and controlled by a controller to manage fluid flow and torsional feedback, allowing for locking and torque adjustment based on vehicle state and mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a steer-by-wire assembly uses an emulator to control the steering wheel, then steering control is achieved, but the system lacks effective mechanisms for providing variable mechanical end stops and locking the steering wheel
Solution Approach 1:
The patent applies pneumatic/hydraulic principles by using a fluid-flow control mechanism with a piston and fluid chamber to provide variable mechanical end stops and locking capability for the steering wheel. The fluid pressure creates controllable resistance and mechanical stopping force, enabling reliable steering wheel locking without complex mechanical linkages.
Solution Approach 2:
The patent replaces traditional mechanical locking mechanisms with a fluid-based control system. Instead of using complex mechanical springs, levers, and linkages for end stops and locking, the system uses fluid pressure acting on a piston to achieve the same functions with simpler mechanical components.
2Reliability
If the steering wheel emulator fails or is not in use, then steering control is lost, but the system needs to maintain desired steering torque and safety
Solution Approach 1:
The patent prepares for emulator failure by providing a passive mechanical backup system using fluid pressure and springs that automatically engage to provide variable end stops and steering torque. This beforehand cushioning ensures that even when the active emulator fails, the steering wheel remains controllable with appropriate mechanical resistance and stopping points.
Solution Approach 2:
The patent changes the operational parameters of the fluid-flow control mechanism based on system state. When the emulator is not in use or fails, the fluid pressure and spring pre-compression are adjusted to provide appropriate mechanical assistance and end stop forces, transforming the system from active electronic control to passive mechanical control.
3Measurement precision
If a fluid-flow control mechanism is used to adjust torque on the steering column, then precise torque control is achieved, but the system requires complex valve control and fluid management
Solution Approach 1:
The patent uses a flow control valve as an intermediary component that simplifies the control of fluid pressure. Instead of directly controlling complex fluid dynamics, the valve acts as a mediator between the control system and the fluid chamber, providing precise torque control through a single controllable element that regulates fluid flow into and out of the chamber.
Solution Approach 2:
The patent segments the fluid control system into distinct functional components: a fluid chamber separated into compartments by a piston, with independent flow control valves for each compartment. This segmentation allows precise control of piston position and torque by managing fluid flow in discrete sections rather than controlling a monolithic fluid system.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise control of steering wheel torque and locking, ensuring safe operation and efficient steering in various vehicle states, including autonomous and failed emulator scenarios, by dynamically adjusting fluid flow and resistance.
Implementation Method 1
The flow control valve is configured to control a flow of a fluid in the cavity of the housing to adjust the torque on the steering wheel
Implementation Method 2
The fluid-flow control mechanism includes a spring coupled to the shaft and the piston to bias the piston's position toward a center of the cavity and the Steering Wheel to the straight head position
Data Source
AI summary
A steer-by-wire assembly includes a steering wheel, a steering column coupled to the steering wheel, and a fluid-flow control mechanism coupled to the steering column, wherein the fluid-flow control mechanism is configured to adjust a torque on the steering column. The fluid-flow control mechanism includes a housing defining a cavity, and a flow control valve in fluid communication with the cavity of the housing. The flow control valve is configured to control a flow of a fluid in the cavity of the housing to adjust the torque on the steering wheel. The fluid-flow control mechanism includes a shaft and a piston coupled to the shaft such that translation of the piston causes the shaft to rotate.