Hybrid Actuator for Spacecraft Vibration Isolation and Agile Pointing
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Solution Overview
Problem
Traditional spacecraft control architectures face instability and reduced agility due to the use of passive isolators, which violate co-location protocols and limit the transmission of high-frequency control torques, necessitating active 'feedforwards' and increased displacement requirements between the payload and bus.
Innovation Solution
A hybrid actuator system comprising a non-contacting actuator and a passive mechanical system coupled in parallel, along with an inertial actuator, is used to independently control the payload and bus, allowing for relative positioning and attitude control, enabling agile and stable pointing without passive connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If passive isolators are used to attenuate bus vibrations to the payload, then vibration isolation is improved, but spacecraft agility deteriorates because high frequency control torques are not passed to the payload
Solution Approach 1:
The patent divides the actuation system into two independent segments: a first actuator coupled to the bus for providing inertial torque, and a second actuator coupled to the payload for providing agile control torque. This segmentation allows each actuator to be optimized for its specific function without interference from the other, resolving the contradiction between vibration isolation and agility.
Solution Approach 2:
The patent introduces a hybrid interface as an intermediary mechanism between the bus and payload. This interface includes both passive isolators for vibration attenuation and active actuators for torque transmission, allowing high-frequency control torques to be passed to the payload while still providing vibration isolation.
2Object-affected harmful factors
If passive isolators are used between the inertial actuator and sensor, then vibration isolation is improved, but co-location protocol is violated resulting in an unstable mode
Solution Approach 1:
The patent segments the control system into independent bus and payload control loops, with the hybrid interface providing controlled coupling. This segmentation allows the inertial actuator to be decoupled from the payload sensor, eliminating the co-location conflict while maintaining vibration isolation through the passive isolators in the hybrid interface.
3Speed
If the payload is controlled to move relative to the bus to meet pointing agility requirements, then pointing agility is improved, but stroke requirements increase
Solution Approach 1:
The patent segments the motion control into two independent actuators: the first actuator handles the bulk inertial motion with larger stroke, while the second actuator handles fine agile adjustments with smaller stroke. This segmentation allows the payload to achieve high pointing agility without requiring excessive stroke from a single actuator.
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
This solution enhances spacecraft agility and stability by allowing independent control of the payload and bus, maintaining relative positions and attitudes, and decoupling isolation and pointing functions, while providing fault tolerance and efficient motion control across nine degrees of freedom.
Implementation Method 1
A hybrid actuator system comprising a non-contacting actuator... configured to maneuver a position and/or an attitude of the payload
Implementation Method 2
passive 'isolators,' which provide tuned stiffness and damping to create a mechanical 'break'
Implementation Method 3
passive mechanical system coupled in parallel... providing vibration isolation
Implementation Method 4
inertial actuator on the bus for applying torques to the spacecraft to control the sensed orientation of the payload
Implementation Method 5
inertial actuator... the only source of 'inertial torque' available
Data Source
AI summary
Apparatus, Systems, and Methods are provided for controlling motion of a spacecraft. One apparatus includes a non-contacting actuator and a passive mechanical system coupled in parallel with one another. A system includes a payload, a bus, and a hybrid actuator including a non-contacting actuator and a passive mechanical system coupled in parallel, and coupled between the bus and the payload. The system also includes an inertial actuator configured to maneuver the bus to maintain a relative position and/or attitude of the bus with respect to the payload. One method includes receiving a signal instructing a first controller to change the position and/or attitude of a payload and utilizing a hybrid system to change the position and/or attitude of the payload. The method also includes receiving the signal at a second controller and utilizing a system to change a position and/or attitude of the bus independent of the payload.