Sliding-Joint Rotation Mechanism That Avoids Gimbal Axis Coupling
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Solution Overview
Problem
Existing rotation mechanisms for optical elements in cameras face challenges with the Gimbal problem, requiring multiple bearings or motors to achieve two degrees of freedom, leading to complex designs.
Innovation Solution
A rotation mechanism with two rotation axes around two points, utilizing a static base, a first and second rotation arm, and a magnetic follower to enable independent rotation in two degrees of freedom with only three mechanical connections, using stationary motors and a magnetic follower to maintain a constant distance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a Gimbal design with internally rotating DOF is used, then two degrees of freedom rotation is achieved, but the rotation axis of the internally rotating DOF is rotated by the external DOF
Solution Approach 1:
Instead of having one arm rotate internally while the other rotates externally (Gimbal design), the patent inverts the approach by having both arms rotate externally around fixed axes. The first rotation arm rotates around a first rotation axis, and the second rotation arm rotates around a second rotation axis, with both axes remaining fixed in space. This inversion eliminates the Gimbal problem where the internally rotating axis would be rotated by the external DOF.
2Reliability
If two fixed motors with more than three bearings are used, then the Gimbal problem is solved, but the device complexity increases
Solution Approach 1:
The patent extracts the unnecessary complexity from traditional solutions by using only two fixed motors with exactly three bearings. The first motor rotates the first rotation arm around the first rotation axis, and the second motor rotates the second rotation arm around the second rotation axis. This minimal configuration eliminates the Gimbal problem without requiring more than three bearings, thereby reducing device complexity while maintaining reliability.
3Reliability
If two rotating motors with two bearings are used, then the Gimbal problem is solved, but the device complexity increases
Solution Approach 1:
The patent extracts the unnecessary complexity by using only two rotating motors with two bearings. The first motor is coupled to the first rotation arm to rotate it around the first rotation axis, and the second motor is coupled to the second rotation arm to rotate it around the second rotation axis. This configuration solves the Gimbal problem while minimizing the number of motors and bearings to exactly two of each.
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 allows for efficient two-degree-of-freedom rotation with reduced mechanical complexity, using fewer bearings and motors, while maintaining precise positional control through decoupled sensing mechanisms.
Implementation Method 1
the follower member is a magnetic member separated from the second rotation arm by a constant air-gap
Data Source
AI summary
Rotation mechanisms for rotating a payload in two, first and second degrees of freedom (DOF), comprising a static base, a first rotation arm coupled mechanically to the static base through a first rotation joint and used for rotating the payload relative to the static base around a first rotation axis that passes through the first rotation joint, a second rotation arm coupled mechanically to the static base through a second rotation joint and used for rotating the payload relative to the static base around a second rotation axis that passes through the second rotation joint, and a follower member rigidly coupled to the payload and arranged to keep a constant distance from the second rotation arm, wherein the rotation of the first arm rotates the payload around the first DOF and the rotation of the second arm rotate the payload around the second DOF.