Three-Point Kinematic Mount for Low-Stress Payload Alignment
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Solution Overview
Problem
Existing kinematic mounts for satellites with large payloads, such as electro-optical satellites, face challenges in addressing displacements due to production inaccuracies and environmental changes like temperature and pressure variations, which can lead to stress and instability in the structure.
Innovation Solution
A kinematic mount design utilizing three pairs of pins and spherical bearings, each pair restricting two degrees of freedom, allowing for six degrees of freedom while minimizing stress and instability. This design includes at least one spherical bearing in contact with an enclosure to manage displacements effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If six single flexures or three pairs of flexures are used to harness the payload in six degrees of freedom, then the payload can be restrained in all desired directions, but the rigid nature of the flexures causes unnecessary stresses to be added to the structure
Solution Approach 1:
The patent changes the stiffness parameter of the mounting elements by transitioning from rigid flexures to compliant mechanisms with adjustable compliance. The compliant mechanisms can be tuned to provide appropriate flexibility in specific directions while maintaining stability, thereby reducing unnecessary stresses on the payload structure.
Solution Approach 2:
The patent introduces dynamic adaptability through compliant mechanisms that can adjust their mechanical properties in response to environmental changes. This allows the mount to maintain optimal performance across varying temperature and pressure conditions without transmitting excessive stresses to the payload.
2Ease of manufacture
If production inaccuracies or assembly force variations occur, then the screw-hole connection applies force onto the screws and harness, but this leads to displacement and stress in the material
Solution Approach 1:
The patent incorporates compliant mechanisms that act as pre-designed cushions to absorb and compensate for assembly inaccuracies and force variations. These mechanisms are built into the structure to tolerate manufacturing tolerances and prevent the transmission of disruptive forces to the payload, thereby maintaining mount stability despite variations in assembly precision.
3Adaptability or versatility
If environmental conditions such as temperature and pressure change over time, then deformation of the rigid body or frame occurs, but this leads to displacement affecting the contact points
Solution Approach 1:
The patent employs compliant mechanisms with adjustable compliance that can dynamically adapt to environmental changes. These mechanisms allow controlled deformation in non-critical directions while maintaining precise positioning in critical contact points, enabling the mount to withstand temperature and pressure variations without compromising contact point precision.
Solution Approach 2:
The patent applies different compliance characteristics to different parts of the mounting structure. Critical contact points maintain high precision and rigidity, while non-critical areas incorporate compliance to absorb environmental deformations. This localized differentiation allows the structure to adapt to environmental changes while preserving manufacturing precision where needed.
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 proposed mount effectively restricts undesirable displacements, maintaining structural integrity and stability under varying environmental conditions, thus ensuring precise and reliable operation of satellite payloads.
Implementation Method 1
a first pin movable within a first spherical bearing while being in contact with the rigid body such that two degrees of freedom restriction are provided to the displacement of the rigid body
Data Source
AI summary
A mount surrounding a rigid body within an enclosure, is provided herein. The mount includes: a first pair of a first pin and first spherical bearing, wherein the first pin is movable within the first spherical bearing while being in contact with the rigid body such that two degrees of freedom (DOF) restriction enable a displacement of the rigid body; a second pair of a second pin and second spherical bearing, wherein the second pin is movable within the second spherical bearing while being in contact with the rigid body such that two DOF restriction enable a displacement of the rigid body; and a third pair of a third pin and third spherical bearing, wherein the third pin is movable within the third spherical bearing while being in contact with the rigid body such that two DOF restriction enable a displacement of the rigid body.