Momentum Wheel Control Using Simulated Angle Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Momentum wheel devices for satellites face challenges in maintaining precise speed control and alignment due to friction, delays, and measurement inaccuracies, leading to deviations in the desired rotational position.
Innovation Solution
A control system that combines a real momentum wheel device with a simulated momentum wheel device based on an ideal physical model, allowing for precise comparison and correction of rotation angles through error signals, ensuring accurate synchronization of speed and position.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a momentum wheel device is used to stabilize a spacecraft, then the gyroscopic effect provides stabilization, but friction in the bearings and control delays cause deviations in the desired rotational position
Solution Approach 1:
The patent creates a simulated momentum wheel device that copies the physical characteristics and behavior of the real momentum wheel device. This simulated model allows for prediction of ideal rotation angles without friction and control delays, enabling comparison with actual performance to generate correction signals.
Solution Approach 2:
The patent implements a feedback mechanism where the deviation between the simulated rotation angle (ideal) and the actual rotation angle (measured) is calculated. This deviation signal is fed back to the control system to generate correction commands, continuously adjusting the momentum wheel to minimize positioning errors caused by friction and delays.
2Speed
If friction peaks occur in the bearings, then statistical changes in friction cause disturbances in speed control, but maintaining precise speed control requires complex compensation mechanisms
Solution Approach 1:
The simulated momentum wheel device replicates the dynamic behavior of the real system, including the effects of friction. By comparing the simulated speed (which accounts for ideal conditions) with the actual speed, the system can detect friction-induced disturbances and compensate for them through the feedback mechanism without requiring complex direct friction measurement and compensation hardware.
Solution Approach 2:
The patent replaces direct mechanical friction compensation mechanisms with a computational approach. Instead of using complex mechanical devices to measure and compensate for bearing friction, the system uses a simulated model and computational algorithms to predict and correct for friction effects, simplifying the physical hardware while maintaining control precision.
3Measurement precision
If control delays and dead times are present, then the desired rotational position is not achieved precisely, but reducing control loop time requires faster processing hardware
Solution Approach 1:
The simulated momentum wheel device performs preliminary calculations of the expected rotation angle based on the torque command and system dynamics model. This allows the control system to predict where the momentum wheel should be at future time points, compensating for known control delays and dead times before they actually affect the positioning accuracy.
Solution Approach 2:
The continuous feedback loop compares the predicted rotation angle from the simulated model with the actual measured rotation angle. This deviation information is used to generate real-time correction commands that compensate for delays in the control system, allowing the momentum wheel to reach the desired position more accurately despite processing time 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
This approach enables precise control of the momentum wheel, minimizing deviations and achieving high accuracy in satellite alignment by compensating for friction and measurement errors, thereby stabilizing the satellite's position effectively.
Implementation Method 1
The momentum wheel is set rotating by a drive, so that a stabilizing effect can be achieved by the gyroscopic effect
Data Source
AI summary
A control method for controlling a momentum wheel device for stabilizing a spacecraft includes: providing the momentum wheel device as a real momentum wheel device having a momentum wheel driven by a motor; providing a simulated momentum wheel device based on an ideal physical model; concurrent feeding of a torque command to both momentum wheel devices, to change a rotational speed of both momentum wheel devices; controlling the motor to change the rotational speed dependent on the fed torque command; detecting a real rotation angle of the real momentum wheel device; calculating a simulated rotation angle of the simulated momentum wheel device by two-fold integration of the fed torque command; comparing the real rotation angle and the simulated rotation angle and generating an error signal corresponding to a deviation between the real and simulated rotation angles; and controlling the motor due to the error signal to reduce the deviation.