Three-Axis Joystick for Electric Vehicle Steering Precision
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Solution Overview
Problem
Conventional joysticks, such as the 2 DoF tilt joystick, are not fast enough and lack precision to fully exploit the responsiveness of electric vehicle (EV) systems, as they require significant arm movement and have a limited tilt range, making them unsuitable for precise steering adjustments over the entire range of steering.
Innovation Solution
A hand-held controller with a joystick that allows three-dimensional movement, utilizing a Y link (yaw) connected to a P link (pitch), which is in turn connected to an R link (roll), enabling rotation around three axes, with sensors to measure these movements and provide counteractive force as needed, allowing for fine-tuned steering and acceleration control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a 2 DoF tilt joystick is used, then the controller is more compact and easier to manufacture, but the operating speed is still too slow and precision is insufficient for EV systems
Solution Approach 1:
The patent transitions from a 2-degree-of-freedom tilt joystick to a 3-degree-of-freedom joystick by adding rotational movement around the joystick's longitudinal axis (yaw axis). This dimensional addition allows the joystick to provide both rapid response for acceleration/braking (pitch) and precise steering control (roll and yaw), simultaneously meeting the speed and precision requirements of EV systems while maintaining a compact form factor.
2Device complexity
If a 2 DoF tilt joystick with pivot point below wrist is used, then the design is simplified and construction is easier, but the required arm movement reduces operating speed
Solution Approach 1:
By adding the third rotational degree of freedom (yaw rotation around the joystick's longitudinal axis), the system enables precise steering control without requiring large arm movements. The yaw rotation allows fine steering adjustments through wrist rotation alone, while the pitch axis handles acceleration and braking, thus maintaining both simplicity and high operating speed.
3Volume of moving object
If a 2 DoF tilt joystick with maximum tilt range of about 90 degrees is used, then the controller is compact, but precise steering adjustments over the entire steering range are very difficult to achieve
Solution Approach 1:
The patent adds two rotational degrees of freedom (roll and yaw) that operate independently of the pitch axis. The roll axis provides coarse steering control with a wide range of motion, while the yaw axis provides fine steering adjustments with high precision. This dimensional decomposition allows the joystick to maintain a compact size while achieving precise steering control across the entire steering range.
4Measurement precision
If a conventional steering wheel is used, then the steering precision is good, but the operating speed is too slow to exploit the responsiveness of EV electric machinery
Solution Approach 1:
The 3 DoF joystick concentrates steering control into two rotational axes (roll and yaw) that can be operated with minimal arm and wrist movements. The roll axis handles primary steering with a wide angular range, while the yaw axis provides fine-tuned steering adjustments. This allows the driver to achieve precise steering control comparable to a steering wheel but with much faster response times suitable for EV electric machinery.
Data Source
AI summary
A controller having a joystick which can be moved in three dimensions is disclosed. The joystick is connected by a Y (yaw) link which is, in turn, connected to a P (pitch) link, which is, in turn connected to an R (roll) link. The R link is rotatable about a fixed-position mounting base. In this manner, one can rotate a joystick around any of three axes. When used to control a vehicle, rotation around the yaw and roll axes can steer (with yaw being more fine-tuned steering), and rotation around the pitch axis can control acceleration and deceleration. A starting or center position for each link can be defined, and the further a link is rotated and/or force increases on tires being steered from this central position, the more resistance is applied, in embodiments of the disclosed technology.