Tetrahedron Space Orientating Mechanism for High-Maneuvering Motion
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Solution Overview
Problem
Current motion platforms, such as 6-axis Stewart platforms and gimbals type multi-ring mechanisms, are limited in simulating high-maneuvering motion in three-dimensional space and providing passengers with a realistic and exciting experience due to restricted rotational and translational degrees of freedom, leading to confined application scopes.
Innovation Solution
A space orientating mechanism featuring inner and outer tetrahedron frames with four arc-link assemblies, allowing for extended rotational and translational degrees of freedom, utilizing motors as torque sources to enhance controllability and maintainability, and incorporating a movable inner frame to avoid singularity and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 6-axis Stewart platform is used, then the mechanism can move in six degrees of freedom, but the moving range of the payload bay is highly confined with rotational angles limited to ±45°
Solution Approach 1:
The mechanism is divided into multiple independent rotational modules (first rotational module for pitch, second rotational module for roll, third rotational module for yaw). Each module can rotate independently within a larger angle range, allowing the payload bay to achieve extended rotational coverage beyond the ±45° limitation of traditional Stewart platforms.
Solution Approach 2:
The patent introduces multiple rotational dimensions by stacking rotational modules along different axes. The first rotational module provides pitch rotation, the second provides roll rotation, and the third provides yaw rotation, creating a multi-dimensional rotational space that significantly expands the accessible angular range compared to conventional single-platform designs.
2Adaptability or versatility
If gimbals type multi-ring mechanism is used, then the payload bay can rotate continuously in large angles, but the mechanism lacks translational degrees of freedom for up/down, left/right and forward/backward motion
Solution Approach 1:
The patent merges the advantages of both Stewart platforms and gimbals type mechanisms by integrating continuous rotational capability with translational degrees of freedom. The mechanism combines rotational modules that enable continuous large-angle rotation with linear actuators that provide translational motion in multiple directions, creating a hybrid system that achieves both rotational continuity and translational freedom.
3Adaptability or versatility
If motors with gearboxes are used to drive the payload bay, then the mechanism can provide continuous rotation, but the total inertia of the motor and gearbox must be large, requiring significantly increased diameter of rings
Solution Approach 1:
The patent replaces traditional motor-gearbox assemblies with direct-drive motors for the rotational modules. This substitution eliminates the need for gearboxes, significantly reducing the moment of inertia and allowing for more compact mechanism dimensions while maintaining continuous rotation capability. The direct-drive motors provide sufficient torque without requiring large-radius rings to accommodate gearbox assemblies.
4Adaptability or versatility
If hydraulic cylinders are used to drive the Stewart platform, then the mechanism can achieve large rotational angles, but the linear actuator extension is substantially limited to fixed length
Solution Approach 1:
The patent employs adjustable-length linear actuators instead of fixed-length hydraulic cylinders. These dynamic actuators can extend and retract to accommodate the varying geometric requirements of large rotational angles. The adjustable length allows the mechanism to maintain proper actuator orientation and force transmission throughout the extended rotational range, overcoming the geometric limitations of fixed-length actuators.
Data Source
AI summary
This new invented mechanism is geometrically defined by two concentric tetrahedrons. Four motors are mounted onto the four vertexes of an outer tetrahedron frame. Four outer arc-links which are driven by these motors are pivotally connected with another four inner arc-links which are pivoted by four vertexes of an inner tetrahedron frame. This mechanism not only extends the range in pitch, roll and yaw three rotational DoF for enlarging the limits of Stewart 6-axis motion platform but also increases two translational DoF for improving the shortage of gimbals type multi-ring mechanism. This mechanism can simulate high maneuvering motion (ex. Barrel roll or fast spin) as high-speed vehicles (ex. fighter or roller coaster) can to stimulate passengers with virtual-but-real and shocked-but-exciting sensation. This mechanism will be chosen as a motion platform or a space orientating mechanism for a theme park game machine or a military fighter trainer.