Mechanical End Stop Detection via Oscillatory Base Motion
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Solution Overview
Problem
Precision motion systems face challenges in accurately determining the position of mechanical end stops, which can lead to damage during transportation and maintenance, due to imprecise methods for ensuring horizontal alignment and potential changes over time.
Innovation Solution
A method involving a six degree-of-freedom active isolation system with actuators and inertial sensors, where a process sensitivity matrix is used to apply a controlled oscillatory motion to detect mechanical contacts with end stops, allowing for precise location and adjustment of the base relative to end stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If shipping brackets are released to allow base movement on dampers, then the system can operate with vibration isolation, but the base may tilt or settle at incorrect height due to damper stiffness and equipment weight
Solution Approach 1:
The patent applies mechanical vibration by inducing controlled oscillatory motion in the selected translational DOF to detect mechanical end stops. The actuators generate oscillations that allow the system to probe the mechanical limits of base movement, enabling precise detection of end stop positions without requiring manual adjustment or shimming operations.
Solution Approach 2:
The patent implements feedback through inertial sensors that continuously monitor the base position and oscillatory motion. The sensor data is processed to detect when the base contacts mechanical end stops, providing real-time feedback on the base position relative to its mechanical limits. This feedback mechanism enables automatic detection and correction of base positioning issues.
2Measurement precision
If shims are used to check and adjust base position, then mechanical end stop location can be verified, but the operation is imprecise and cumbersome
Solution Approach 1:
The patent replaces the mechanical shim-based measurement system with an automated sensor-based detection system. Inertial sensors and actuators substitute for manual shim insertion and measurement operations, providing precise, automated detection of end stop positions. This substitution eliminates the imprecision and labor-intensive nature of shim-based methods.
Solution Approach 2:
The system performs self-diagnosis and self-measurement by using its own actuators and sensors to detect end stop positions. The motion system autonomously generates oscillatory motion and monitors its own response to determine mechanical limits, eliminating the need for external measurement tools and manual operations.
3Manufacturing precision
If the base is adjusted to be horizontal, then proper alignment is achieved, but there is no guarantee that the height corresponds to the middle of vertical end stops
Solution Approach 1:
The patent uses mechanical vibration in the vertical translational DOF to detect the positions of upper and lower mechanical end stops. By inducing oscillatory motion and monitoring the base response, the system can precisely determine the vertical limits of travel, thereby accurately locating the end stops relative to the base height without requiring manual measurement.
Solution Approach 2:
The inertial sensors provide continuous feedback on the base vertical position during oscillatory motion. This feedback enables the system to precisely determine when the base contacts the upper or lower mechanical end stops, providing accurate information about the relationship between base height and end stop positions.
4Reliability
If periodic maintenance is performed to check base position, then changes due to damper creep can be detected, but manual measurement methods are insufficient
Solution Approach 1:
The system performs periodic self-diagnosis by autonomously executing the oscillatory motion detection routine to check base position relative to mechanical end stops. This self-service capability allows the system to automatically detect changes in base positioning caused by damper creep or other degradation, eliminating the need for external measurement tools and manual procedures.
Solution Approach 2:
The inertial sensors provide continuous feedback on base position that can be monitored during periodic maintenance operations. This feedback mechanism enables precise detection of position drift caused by damper creep, allowing for timely corrective action to maintain system reliability.
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 method prevents damage by accurately detecting and locating mechanical end stops, enabling precise alignment and periodic maintenance, thus ensuring the stability and accuracy of precision motion systems.
Implementation Method 1
determining, using a process sensitivity matrix of a mechanical system comprising the base and the active isolation system, a force to be applied to the base by the actuators to cause an oscillatory motion of the base in the selected translational DOF
Implementation Method 2
providing a six DOF measurement of motion of the base
Data Source
AI summary
A method is provided for detecting a mechanical end stop of a motion system comprising a base designed to receive a motion stage, a machine frame and an active isolation system comprising actuators arranged to impart a six degree-of-freedom (DOF) motion to the base, inertial sensors arranged to provide a six DOF measurement, the mechanical end stop being arranged to limit the base's motion relative to the machine frame. The method includes selecting a translational DOF, and determining, using a process sensitivity matrix of a mechanical system comprising the base and the active isolation system, a force to be applied to the base by the actuators to cause an oscillatory motion of the base in the translational DOF. The method further includes applying the force to obtain the oscillatory motion, and detecting a mechanical contact between the base and the mechanical end stop using the inertial sensors.