Steerable Mirror Positioning Control with Dynamic Loop Gain
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Solution Overview
Problem
Conventional steerable mirror control systems for laser drilling machines experience increased overshoot and prolonged positioning times due to temperature variations, which are not effectively addressed by existing methods.
Innovation Solution
A positioning control system with a loop gain modifier that adjusts the loop gain based on the difference between measured overshoot and undershoot during positioning operations, allowing for real-time compensation to maintain accurate and efficient tracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional feedback control is used with fixed loop gain, then system stability is maintained, but positioning time increases and accuracy deteriorates under temperature variations
Solution Approach 1:
The loop gain is changed from a fixed value to a dynamically adjustable parameter that varies with operating conditions. The loop gain modifier continuously adjusts the loop gain based on the difference between actual and target positioning times, enabling the system to adapt to temperature variations and other environmental changes while maintaining optimal positioning performance.
Solution Approach 2:
A feedback mechanism is introduced where the actual positioning time is measured and compared with the target positioning time. The loop gain modifier uses this time difference feedback to automatically adjust the loop gain, creating a closed-loop control system that optimizes positioning speed while maintaining stability under varying conditions.
2Reliability
If conventional feedback control with fixed loop gain is used, then system stability is maintained, but positioning accuracy deteriorates due to temperature variations
Solution Approach 1:
The loop gain is transformed from a static parameter to a dynamic one that adapts to temperature variations. By continuously adjusting the loop gain based on actual positioning performance, the system maintains high positioning accuracy across different temperature conditions while preserving system stability.
Solution Approach 2:
The loop gain parameter is modified in response to temperature variations and positioning performance. The loop gain modifier changes the loop gain value to optimize the feedback control characteristics, enabling the system to maintain manufacturing precision despite environmental changes that would otherwise degrade accuracy.
3Loss of time
If loop gain is increased to reduce positioning time, then positioning speed improves, but system stability deteriorates
Solution Approach 1:
Instead of using a fixed high loop gain that compromises stability, the system dynamically adjusts the loop gain to the optimal value for current operating conditions. The loop gain modifier ensures the loop gain is high enough to achieve fast positioning when conditions permit, but reduces it when stability becomes compromised, thereby resolving the trade-off between speed and stability.
4Device complexity
If conventional control without loop gain modification is used, then system simplicity is maintained, but positioning performance deteriorates under temperature variations
Solution Approach 1:
A feedback loop is added where the actual positioning time is measured and used to adjust the loop gain. This relatively simple feedback mechanism enables the system to automatically compensate for temperature variations and maintain high positioning accuracy without requiring complex prediction models or external temperature sensors.
Solution Approach 2:
The control system performs self-adjustment by using its own positioning performance data to modify the loop gain. The loop gain modifier enables the system to self-correct for temperature variations and other environmental effects without external intervention, maintaining accuracy while adding minimal complexity.
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 effectively suppresses overshoot and reduces positioning time, enabling high-speed and high-accuracy positioning of the steerable mirror, even under temperature fluctuations.
Implementation Method 1
an electromagnetic rotary actuator that generates drive torque electromagnetically
Implementation Method 2
an electromagnetic rotary actuator that generates drive torque electromagnetically is often employed. This rotary actuator also includes a built-in sensor for detecting the angle of the steerable mirror
Implementation Method 3
a value obtained by subtracting the detected angle data from the angle command data, in other words, a tracking error signal is integrated with respect to time
Implementation Method 4
a laser drilling machine for performing drilling in a fabrication process of a printed circuit board
Data Source
AI summary
A positioning control system for positioning a moving element on a basis of position command data is provided with a feedback loop. The system is also provided with a loop gain modifier for determining a loop gain, which is to be used in a following positioning operation, on a basis of a difference between an amount of overshoot measured in a current positioning operation and a predetermined tolerance or on a basis of a difference between an amount of overshoot measured in a current positioning operation and a first predetermined tolerance and a difference between an amount of undershoot measured in the current positioning operation and a second predetermined tolerance. The first and second tolerances may preferably be the same in absolute value. The moving element may specifically be a steerable mirror for drilling holes in a work by reflecting a laser beam. Also disclosed is a laser drilling machine including the system.