3-DOF Motion Generator with Rotary Yaw Platform
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Solution Overview
Problem
Current motion simulation systems, particularly hexapod-based systems, have limitations in bandwidth, complexity, cost, and restricted yaw rotation, which affect the naturalness and responsiveness of simulated vehicle movements, especially in high-end applications like military and commercial flight training.
Innovation Solution
A motion generator with a rotatable platform on a circular guide, featuring multiple linear guides and actuators, allowing for 360° rotation and high excursion in three degrees of freedom, enabling precise control and compact design, suitable for vehicle driving and flying simulations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hexapod-based motion generators are used, then six degrees of freedom movement is achieved, but bandwidth is limited to about 20 Hz
Solution Approach 1:
The motion generator is divided into two independent parts: a Stewart platform for six degrees of freedom movement and a separate rotary mechanism for yaw rotation. This segmentation allows each subsystem to operate independently, enabling the rotary mechanism to achieve high bandwidth yaw rotation (beyond 20 Hz) while the Stewart platform handles the positional movements, thus resolving the bandwidth limitation of conventional integrated hexapod systems.
Solution Approach 2:
The rotary mechanism is integrated with the Stewart platform to provide both yaw rotation and six degrees of freedom movement through a unified control system. This multi-functionality allows the system to achieve high bandwidth performance in yaw rotation while maintaining the six degrees of freedom capability, effectively resolving the contradiction between bandwidth and frequency content transmission.
2Speed
If dedicated vehicle driving simulator motion systems are used, then responsiveness in some directions is improved, but mechanical complexity and cost increase
Solution Approach 1:
The system segments the motion generation into a Stewart platform for positional movements and a separate rotary mechanism for yaw rotation. This segmentation reduces mechanical complexity compared to dedicated systems with precision machined custom components, while maintaining responsiveness through the independent control of each subsystem. The modular design simplifies the overall mechanical structure while preserving performance.
Solution Approach 2:
The patent replaces complex mechanical linkages with a more straightforward rotary mechanism that uses a motor directly driving the yaw rotation. This substitution reduces mechanical complexity and cost while maintaining or improving responsiveness, as the direct drive mechanism eliminates the need for complex gear trains and precision machining found in traditional dedicated systems.
3Measurement precision
If ball screws are used in motion systems, then position establishment is improved, but force transfer is inhibited and bandwidth is reduced
Solution Approach 1:
The patent replaces ball screws with direct linear motor drives for the Stewart platform actuators. This substitution eliminates the mechanical coupling and friction inherent in ball screw mechanisms, allowing for improved force transfer and higher bandwidth operation. The direct drive system maintains position precision through electronic control while achieving better dynamic performance and force transmission.
4Adaptability or versatility
If hexapod-based systems are used, then six degrees of freedom movement is achieved, but yaw rotation is restricted to about 25°
Solution Approach 1:
The system segments the yaw rotation function into a separate rotary mechanism that is independent of the Stewart platform. This segmentation allows the yaw mechanism to rotate freely through 360° or more without being constrained by the hexapod geometry, while the Stewart platform maintains its six degrees of freedom capability. The independent rotary mechanism provides unrestricted yaw rotation while the platform handles positional movements.
Solution Approach 2:
The rotary mechanism is integrated with the Stewart platform to provide both yaw rotation and six degrees of freedom movement through a unified control system. This multi-functionality enables the system to achieve 360° or greater yaw rotation while maintaining full six degrees of freedom capability, effectively resolving the contradiction between yaw rotation range and operational freedom.
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
The solution provides enhanced yaw characteristics, improved naturalness, and responsiveness in vehicle simulations by allowing 360° rotation and high excursion movements, making it suitable for high-end applications while being compact and cost-effective.
Implementation Method 1
Each of the linear motors (101, 201, 301) generates a corresponding electromagnetic force in interaction with the magnet way (615) to move the linear guide carriage (102, 202, 302) along the linear guide (103, 203, 203) respectively
Implementation Method 2
The peripheral guide carriage (104, 204, 304) and the rotatable platform (12) include a linear motor coil (24) and a corresponding linear motor magnet way (26) which generate a corresponding electromagnetic force to rotate the rotatable platform (12)
Data Source
AI summary
This invention relates to a three degree of freedom motion generator for moving a payload above the surface, the motion generator comprising a rotatable platform arranged for rotation on a circular guide above the surface, at least three linear guides extending ray-wise above the surface from a centre, each linear guide having a linear guide carriage moveable thereon, a peripheral guide carriage pivotally mounted on each linear guide carriage about the periphery of the rotatable platform, and a plurality of actuators, whereby at least one actuator may be operated to exert a force between a peripheral guide carriage on the circular guide and the rotatable platform. Other aspects include a motion system, and vehicle driving simulators including such a motion generator.