Spherical Orienting Mechanism With Fixed Motors for Rapid Precision Motion
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Solution Overview
Problem
Conventional two-axis spherical orienting mechanisms face limitations in rapid movement due to increased moment of inertia caused by actuating motors that need to be displaced by the outer gimbal.
Innovation Solution
A spherical orienting mechanism with a closed frame encompassing the payload support, utilizing two drive assemblies with motors fixed to the frame, and supported by loaded duplex bearing assemblies to enhance rigidity and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If actuating motors are carried and displaced by the outer gimbal, then the mechanism can achieve two-axis spherical orientation, but the moment of inertia increases, limiting rapid movement capability
Solution Approach 1:
The actuating motors are extracted from the moving outer gimbal and repositioned to fixed positions relative to the base. This removes the source of increased moment of inertia from the moving components, enabling rapid movement while preserving the two-axis spherical orientation capability through the spherical five-bar mechanism linkage.
Solution Approach 2:
Instead of mounting motors on the moving gimbal (conventional approach), the invention inverts the arrangement by mounting motors on the fixed base and using mechanical linkages (spherical five-bar mechanism) to transmit motion to the payload. This inversion resolves the contradiction by decoupling the motor mass from the moving components.
2Speed
If motors are positioned in fixed relation to the base, then moment of inertia is reduced for rapid movement, but the mechanical linkage complexity increases
Solution Approach 1:
The spherical five-bar mechanism serves multiple functions simultaneously: it transmits rotational motion from the fixed motors to the payload, maintains spherical orientation constraints, and provides two degrees of freedom for positioning. This multi-functionality reduces the need for additional complex components while achieving rapid movement capability.
Solution Approach 2:
The invention employs a spherical five-bar mechanism where all movement occurs on the surface of a sphere centered at the payload. This spherical geometry naturally constrains the motion to maintain orientation while allowing complex positioning through coordinated rotation of the five bars, elegantly solving the complexity issue through geometric constraints.
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 mechanism achieves enhanced precision, repeatability, and resistance to external vibrations, allowing for high-precision, rapid orientation of payloads about two axes.
Implementation Method 1
the first drive arm is supported relative to the frame for rotation about the first drive axis by a first set of two bearing assemblies located on opposite sides of the center of rotation
Data Source
AI summary
A mechanism for orienting a payload support includes first and second transversely deployed drive assemblies, each having a motor that drives a drive arm. The payload support is directly pivotally mounted to a first drive arm. Connection between the second drive arm and the payload support is via a coupling linked to the second drive arm via a coupling rotary joint, and to the payload support via a support rotary joint. Both the first drive arm and the second drive arm are supported relative to the frame by sets of two bearing assemblies located on opposite sides of the center of rotation. Each of the bearing assemblies is preferably implemented as a loaded duplex bearing assembly, and most preferably with a back-to-back loaded duplex bearing assembly on each axis.