Piezoelectric Inertia Actuator With Decoupled Preload Zones
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Solution Overview
Problem
Precise control of preload in piezoelectric inertia actuators is difficult, and unwanted changes in preload between engaging bodies and carriages occur, affecting the reliability and precision of motion control.
Innovation Solution
The design incorporates a first preload zone with a tension member and piezo preload body to maintain compressive stress in the piezo body, and a second preload zone with a spring blade and decoupling preload body to adjustably apply preload to the engaging body, ensuring minimal interference between the two zones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a biasing force or preload is applied between the engaging body and the carriage to control friction, then precise control of carriage position is improved, but unwanted changes to the preload between the engaging body and the carriage occur
Solution Approach 1:
The actuator is divided into two separate preload zones: a first preload zone that applies preload to the piezoelectric body, and a second preload zone that applies preload to the engaging body. This segmentation allows independent control of each preload without interference between them, resolving the contradiction by enabling precise carriage position control while maintaining stable preload at the friction interface.
Solution Approach 2:
A decoupling preload body is introduced as an intermediary element between the spring blade and the engaging body. This decoupling preload body acts as a mediator that isolates the preload application to the engaging body from the piezoelectric body preload, preventing unwanted changes in the friction interface preload while maintaining precise position control.
2Reliability
If preload is applied to the piezoelectric device to ensure safe operation, then reliability is improved, but precise control of the frictional interface becomes difficult
Solution Approach 1:
The actuator is divided into two separate preload zones: a first preload zone that applies preload to the piezoelectric body, and a second preload zone that applies preload to the engaging body. This segmentation allows independent control of each preload without interference between them, resolving the contradiction by enabling precise carriage position control while maintaining stable preload at the friction interface.
Solution Approach 2:
A decoupling preload body is introduced as an intermediary element between the spring blade and the engaging body. This decoupling preload body acts as a mediator that isolates the preload application to the engaging body from the piezoelectric body preload, preventing unwanted changes in the friction interface preload while maintaining precise position control.
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 design allows for precise control of preload, maintaining consistent friction at the contact point while minimizing changes in preload on the piezo body, enhancing the reliability and precision of the actuator's operation.
Implementation Method 1
They operate on the principle of stick-slip friction wherein a piezoelectric device expands or contracts based on an alternating electrical signal
Implementation Method 2
At least one spring blade may extend from the coupling body, the spring blade configured to apply a preload biasing force to the flexible frame and the engaging body
Implementation Method 3
The piezoelectric inertia actuator further includes at least one tension member positioned within a tension member receiver and configured to selectively apply a preload force to the piezo body, thereby creating a net compressive stress within the piezo body
Implementation Method 4
this alternating change in size is transferred to a carriage or moving stage via a frictional contact with an engaging body
Data Source
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AI summary
A piezoelectric inertia actuator is disclosed herein, which includes an actuator body, a coupling body defining a receiver, a lock body positioned within the receiver, and a piezo body attached to the coupling body. At least one flexible frame configured to support an engaging body may extend from the piezo body. A spring blade configured to apply a preload force to the engaging body via a decoupling preload body may extend from the coupling body. A tension member may be positioned within the lock body and apply a preload force to the piezo body, thereby creating a net compressive stress therein. The piezoelectric inertia actuator may further include a piezo preload body configured to apply a reaction force to the piezo body in order to maintain the compressive stress therein. The preload applied to the piezo body may be substantially decoupled from the preload applied to the engaging body.