Momentum Wheel Control Using Ideal Model Feedback Synchronization
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Solution Overview
Problem
Swirl wheel devices for satellite stabilization face challenges in maintaining precise rotational control due to deviations caused by finite control speeds, delays, and varying bearing friction, leading to inaccuracies in rotational position and orientation.
Innovation Solution
A control system that incorporates a simulated swirl wheel device based on an ideal physical model, allowing for precise comparison with the real swirl wheel device to generate error signals for motor control adjustments, thereby reducing deviations and achieving synchronization between the real and ideal rotational speeds and angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional speed control with torque commands is used, then motor power level is controlled, but delays and deviations occur leading to satellite orientation errors
Solution Approach 1:
The control algorithm calculates the desired wheel angle in advance based on the torque command and system dynamics model, before the actual wheel response occurs. This predictive approach compensates for control delays by preparing the correction signal ahead of time, reducing the phase lag between command and actual wheel position.
Solution Approach 2:
The system continuously measures the actual wheel angle and rotational speed, then feeds this information back to the control algorithm. The feedback loop compares the measured values with the desired values and generates correction signals to minimize deviations, ensuring accurate satellite orientation despite delays in the control system.
2Reliability
If bearing friction is present in the swirl wheel device, then rolling movement occurs, but friction varies statistically and systematically causing speed control disruptions
Solution Approach 1:
The control algorithm continuously monitors the actual rotational speed and uses this feedback to detect friction-induced deviations. By comparing the measured speed with the commanded speed, the system identifies friction effects and generates compensating torque signals to maintain stable speed control despite varying bearing friction.
Solution Approach 2:
The control algorithm dynamically adjusts the torque command parameter to compensate for friction variations. When friction increases (detected through speed deviations), the algorithm increases the torque command to counteract the frictional losses, maintaining the desired rotational speed despite changing friction conditions.
3Measurement precision
If the swirl wheel speed is controlled accurately, then rotational position is maintained, but finite control speeds cause deviations from desired rotational behavior
Solution Approach 1:
The control algorithm predicts the desired wheel angle in advance based on the torque command and system dynamics, before the finite control speed can cause significant deviations. This preliminary calculation of the target position allows the system to proactively adjust for control delays and maintain accurate rotational positioning.
Solution Approach 2:
The control algorithm incorporates the dynamic characteristics of the swirl wheel device, including its moment of inertia and response time constants. By modeling the dynamic behavior, the algorithm optimizes the control signals to achieve accurate positioning while accounting for the finite speed at which the system can respond to commands.
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 swirl wheel device, minimizing rotational deviations and ensuring accurate satellite orientation by compensating for friction and measurement errors, thereby enhancing the control accuracy to better than 1 μs precision.
Implementation Method 1
The swirl wheel is set in rotation by a drive so that a stabilizing effect can be achieved through the gyroscopic effect
Data Source
AI summary
A control system for a momentum wheel device is specified, wherein the momentum wheel device is a real momentum wheel device (1) and has a momentum wheel which is driven by a motor, and wherein a simulated momentum wheel device (2) is provided which simulates the behaviour of an ideal momentum wheel on the basis of an ideal physical model (12). The rotational speed of both the real momentum wheel device (1) and of the simulated momentum wheel device (2) can be changed by a torque command (6). A comparator device (11) is provided for comparing the real rotational angle (9) of the real momentum wheel device (1) and the simulated rotational angle (14) of the simulated momentum wheel device (2) and for generating a fault signal (15) corresponding to a deviation between the real rotational angle (9) and the simulated rotational angle (14). The fault signal (15) can be conducted to a control device (3), in order to actuate the motor on the basis of the fault signal (15), for the purpose of reducing the deviation.