Friction Drive Satellite Attitude Control System
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Solution Overview
Problem
Existing satellite attitude control systems using electromagnetic or piezoelectric actuators are bulky, interfere with sensitive electronics, and suffer from vibrational cross-talk and installation complexities, particularly in compact satellite designs.
Innovation Solution
A friction drive-based satellite positioning system utilizing a spherical inertial body with passive or semi-active supports and actuators that create rotational momentum through friction, allowing 3D rotation and controlled by feedback sensors, which can be passive, semi-active, or actively vibrated to reduce friction and enhance rotational precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If electromagnetic actuators are used to rotate the spherical inertial body, then rotational control is achieved, but the system becomes bulky and interferes with sensitive electronics
Solution Approach 1:
The patent replaces electromagnetic actuators with a friction-based mechanical actuation system. A motor-driven roller presses against the spherical inertial body to create frictional force that rotates the sphere, eliminating bulky electromagnetic components and their associated interference with sensitive satellite electronics.
Solution Approach 2:
The actuation system is segmented into separate functional components: a motor-driven roller that applies frictional force to the sphere, and a separate magnetic bearing system that provides contactless support. This segmentation allows each component to be optimized independently and reduces overall system complexity.
2Measurement precision
If piezoelectric actuators are used to create rotational movement, then precise orientation is achieved, but vibrational cross-talk and installation complexities occur
Solution Approach 1:
The patent replaces piezoelectric actuators with a friction-based mechanical actuation system using a roller pressing against the sphere. This eliminates the complex segmented electrode structure of piezoelectric actuators and their associated vibrational cross-talk issues, while maintaining rotational control capability.
Solution Approach 2:
The patent uses controlled mechanical vibration through the friction contact between the roller and sphere to reduce static friction and enable smoother rotation, replacing the vibrational mechanism of piezoelectric actuators with a less intrusive friction-based approach that avoids cross-talk.
3Weight of stationary object
If contactless magnetic bearing support is used for the spherical rotor, then size and weight are reduced, but friction-based actuation requires contact
Solution Approach 1:
The system is divided into two independent subsystems: a contactless magnetic bearing system for support and positioning, and a separate friction-based roller actuation system for rotation. This segmentation allows the magnetic bearing to minimize weight without compromising actuation capability, as the roller provides the necessary contact force.
Solution Approach 2:
The friction roller acts as an intermediary between the motor and the spherical inertial body, transferring rotational motion through frictional contact. This intermediary enables mechanical actuation while the magnetic bearing maintains contactless support, resolving the contradiction between contactless support and contact-based actuation.
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 system achieves precise and efficient satellite orientation with reduced size, weight, and interference, enabling effective attitude control in space while minimizing the complexity and cost of the control system.
Implementation Method 1
A friction drive-based satellite positioning system utilizing a spherical inertial body with passive or semi-active supports and actuators that create rotational momentum through friction
Implementation Method 2
supports, which can be passive, semi-active, or actively vibrated to reduce friction and enhance rotational precision
Data Source
AI summary
This disclosure relates to a satellite attitude control apparatus, comprising a spherical inertial body (1), which is arranged to be rotated in space in a desired rotational mode, one or more rotational feedback sensors. The apparatus further comprises a set of supports (3) and/or actuators (2), whereas one or more actuator is used to create rotational momentum to the spherical inertial body through friction. A set of three or more actuators and supports is used in order to keep the inertial body in place. Three or more supporting elements (supports and actuators) are used in combination with magnetic attraction or four or more supporting elements are used in case magnetic attraction is not in use. Supports can be passive or semi-active in order to reduce friction.