Servo Control System for Steerable Mirror with Digital Filter Compensation
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Solution Overview
Problem
Conventional techniques for laser drilling machines fail to achieve high-speed and high-accuracy positioning without extending positioning time, leading to potential deterioration in positioning accuracy due to residual vibrations and varying initial state values during rapid angle command sequences.
Innovation Solution
A servo control system with an additional input mechanism for the feedback loop, utilizing digital filters to compensate for initial state values and stabilize torsional vibrations, allowing for precise control of the steerable mirror's angle and improving settling responses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the positioning time is shortened to increase productivity, then the drilling throughput is improved, but the positioning accuracy deteriorates due to residual vibrations and varying initial state values
Solution Approach 1:
The system performs preliminary compensation by detecting initial state values (position and velocity) before positioning operations begin, and pre-calculates compensation amounts to be applied during the positioning process. This preliminary preparation enables accurate positioning even when positioning time is shortened, as the compensation is already prepared in advance.
Solution Approach 2:
The system dynamically changes control parameters by adjusting compensation amounts based on detected initial state values. The compensation amount is calculated as a function of the initial state, allowing the control system to adapt to varying conditions and maintain positioning accuracy across different operating speeds and initial states.
2Speed
If the feedback loop bandwidth is increased to improve response speed, then the positioning speed is improved, but torsional vibrations are amplified
Solution Approach 1:
The system uses feedback by detecting the initial state values (position and velocity) of the steerable mirror and using this information to calculate appropriate compensation amounts. This feedback mechanism allows the system to adjust control actions based on actual system state, enabling high-speed positioning while compensating for vibrations that would otherwise be amplified by the wide-band feedback loop.
Solution Approach 2:
The compensation amount acts as an intermediary that mediates between the high-bandwidth feedback control and the torsional vibrations. By introducing this intermediate compensation signal based on initial state detection, the system can maintain the benefits of wide-band control while suppressing the harmful vibration effects.
3Productivity
If the command interval is shortened to increase productivity, then the drilling throughput is improved, but the settling response becomes unstable due to varying initial state values
Solution Approach 1:
The system performs preliminary detection of initial state values and pre-calculates compensation amounts before each positioning operation, even when command intervals are short. This preliminary action ensures that stability compensation is ready in advance, making the settling response stable regardless of how frequently commands are issued.
Solution Approach 2:
The system dynamically changes compensation parameters based on detected initial state values for each command. By adjusting the compensation amount according to the specific initial state of each positioning operation, the system maintains stable settling responses even when command intervals are shortened and operating conditions vary.
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
Enables high-speed and high-accuracy positioning of the steerable mirror, reducing residual vibrations and maintaining accurate control within narrower settling response tolerances, thereby enhancing machining throughput and precision.
Implementation Method 1
As the rotary actuator, an electromagnetic actuator is used in common. This electromagnetic actuator generates a drive torque according to an electromagnetic principle.
Implementation Method 2
The angle of a rotation of the steerable mirror is detected by the sensor, and the detected angle data is fed to a feedback control circuit.
Data Source
AI summary
A difference between each position command data outputted in a form of a step signal from a high-level controller and its corresponding detected position data of a movable body is integrated by an integral compensator to position the movable body. Assuming, for example, that the movable body is a steerable mirror, digital filters are arranged to compensate the value of an initial state of an angular displacement and the value of an initial state of an angular velocity, respectively, and respective impulse responses of the digital filters as additional input elements are added to an output terminal of the integral compensator. For higher effectiveness, internal state variables of the digital filters can desirably be cleared to zero whenever an angle (position) command data is received.