Three-Axis Platform Tracking Control Using Kalman Filter Vibration Damping
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Solution Overview
Problem
Platforms with target tracking devices that can pivot about three spatial axes face instability due to vibrations, making target tracking difficult when only position interfaces are available, as conventional methods for damping vibrations require torque interfaces.
Innovation Solution
A method using a Kalman filter to estimate target movement, adjust filter parameters, and generate positioning commands to dampen vibrations, even with only a position interface, by determining actual and target positions, reconstructing target position, and adjusting filter parameters based on detected oscillations in the innovation sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the platform operates with high system dynamics to track moving targets, then tracking performance is improved, but vibrations occur that cause instability in the tracking circuit
Solution Approach 1:
The invention dynamically adjusts the filter parameters (cut-off frequency) based on the detected vibration conditions. When vibrations are detected through the innovation sequence analysis, the filter adapts its characteristics to suppress the vibrations while maintaining tracking performance. This dynamic adaptation allows the system to operate effectively across varying conditions without compromising stability.
Solution Approach 2:
The system implements a feedback mechanism where the innovation sequence from the Kalman filter is continuously monitored to detect vibrations. Based on this feedback, the filter parameters are adjusted in real-time to dampen vibrations. This closed-loop control ensures that the system maintains stability while tracking moving targets, resolving the contradiction between tracking performance and circuit stability.
2Object-affected harmful factors
If vibration damping is implemented using conventional methods (differential speed feedback or state control), then vibrations are reduced, but these methods require torque interfaces which are not available on platforms with only position interfaces
Solution Approach 1:
The invention replaces the need for torque interfaces (mechanical control) with a signal processing approach using Kalman filtering and innovation sequence analysis. By substituting the mechanical vibration damping method with a computational method that operates on position data alone, the system achieves vibration damping without requiring additional torque interfaces, thus reducing device complexity while maintaining effectiveness.
Solution Approach 2:
The system uses its existing position interface and Kalman filter to self-diagnose vibrations through the innovation sequence and self-correct by adjusting filter parameters. This self-service capability allows the platform to dampen vibrations using only the position interface it already possesses, eliminating the need for additional torque interfaces or external vibration sensing equipment.
3Measurement precision
If sensors are used to detect platform position and orientation, then tracking accuracy is improved, but the sensors also detect vibrations which hinder or prevent target tracking
Solution Approach 1:
The invention extracts the vibration component from the sensor signals by analyzing the innovation sequence of the Kalman filter. The innovation sequence represents the difference between actual measurements and predicted values, effectively isolating the vibration component from the useful tracking signals. This extracted vibration information is then used to adjust filter parameters, removing the harmful vibration effects while preserving the accurate tracking data.
Solution Approach 2:
The Kalman filter acts as an intermediary between the sensors and the tracking control system. It processes the raw sensor data, separating useful position and orientation information from vibration noise. The filter's innovation sequence serves as an intermediate indicator that reveals vibration conditions without directly using the vibration-contaminated sensor signals, enabling accurate tracking despite sensor-detected vibrations.
Data Source
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AI summary
A method for controlling the position of a target tracking device with a platform (1) pivotable about three spatial axes comprises the steps: a) determining the actual position of the platform (1); b) determining a deviation of the actual position from a target position for the platform (1) in which a target acquisition device (2) provided on the platform (1) is aimed at a target (T) located at a target position (PT); c) reconstructing an absolute target position from the actual position of the platform (1) determined in step a) and the deviation determined in step b); d) estimating a motion trajectory of the target (T) using a filter (42), preferably a Kalman filter; e) generating a positioning command for the platform (4) by means of a control device (4) having a tracking controller (40) to move to the target position based on the deviation determined in step b) and the motion trajectory estimated in step d);f) Applying the control command generated in step e) to a motion device (3) for the platform (1); g) wherein vibrations of the deviation determined in step b) are detected by means of the filter (42) and, in the event of deviations occurring, filter parameters and/or gain factors in the tracking controller (40) are adjusted.;