Piezo-Hydraulic Lifter for Rapid Precision Positioning
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Solution Overview
Problem
Conventional spindle and piezo drives for lifting and positioning loads face challenges in precise synchronization and uniform lifting due to manufacturing tolerances, especially in parallel hydraulic systems, leading to difficulties in achieving rapid and accurate positioning.
Innovation Solution
The use of a system comprising multiple piezo actuators generating pressure forces, a hydraulic transmission device converting these forces into a vertical pressure, and a spring system to counteract the pressure force, with a centralized fluid system and symmetrical configuration to achieve precise and rapid vertical movement of objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If multiple piezo actuators are used in parallel hydraulic systems to lift objects rapidly, then lifting speed is improved, but synchronization precision and uniform lifting deteriorate due to manufacturing tolerances
Solution Approach 1:
The patent merges multiple piezo actuators into a single integrated drive unit where all actuators work together through a common hydraulic system. The piezo actuators are coupled to a shared piston or hydraulic chamber, ensuring that their combined force is transmitted uniformly through the incompressible hydraulic fluid, eliminating synchronization issues between individual actuators.
Solution Approach 2:
The patent introduces a hydraulic transmission device as an intermediary between the piezo actuators and the load. This intermediary converts the lateral expansion forces of multiple piezo actuators into unified vertical lifting force through hydraulic pressure, automatically equalizing force distribution and eliminating the need for precise mechanical synchronization.
2Measurement precision
If piezo actuators are used for precise positioning, then positioning accuracy is improved, but lifting speed deteriorates due to articulated transmission mechanisms
Solution Approach 1:
The patent replaces traditional articulated mechanical transmission mechanisms with a direct hydraulic transmission system. The piezo actuators directly generate hydraulic pressure through their expansion, which immediately translates to vertical motion without mechanical linkages, thereby maintaining both high speed and high precision positioning capabilities.
Solution Approach 2:
The patent employs hydraulic transmission to convert the rapid lateral expansion of piezo actuators into controlled vertical motion. The incompressible nature of hydraulic fluid ensures that the full expansion speed of the piezo actuators is transferred to the vertical lifting motion, eliminating the speed limitations imposed by mechanical articulated transmissions.
3Measurement precision
If spindle drives are used for lifting and positioning, then positioning capability is improved, but device complexity and maintenance requirements worsen
Solution Approach 1:
The patent replaces complex spindle drive mechanisms with a simpler piezo-hydraulic system. The piezo actuators directly generate force through their piezoelectric effect, which is transmitted through hydraulic fluid to produce vertical motion, eliminating the need for complex mechanical components such as spindles, nuts, and bearings while maintaining precise positioning capability.
Solution Approach 2:
The patent changes the fundamental operating principle from mechanical rotation (spindle drives) to direct piezoelectric expansion with hydraulic transmission. This parameter change simplifies the system by eliminating mechanical transmission components while maintaining the ability to achieve precise positioning through controlled piezo actuator expansion.
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 the rapid and precise vertical movement of objects with masses between 100 g to 1000 g, achieving a stroke of 0.5 to 5 mm within 1 to 10 ms with positioning accuracy better than 10 μm, while reducing the likelihood of object tipping.
Implementation Method 1
a plurality of piezo actuators that expand in directions upon activation and in the process generate pressure forces on an active side
Implementation Method 2
a hydraulic transmission device which converts the pressure forces of the piezo actuators into a vertical pressure force for moving the object counter to the direction of gravity and transmits said pressure forces with a transmission ratio
Implementation Method 3
a spring system acts between the object to be moved and the hydraulic transmission device with its spring force counter to the vertical pressure force of the hydraulic transmission device
Implementation Method 4
all of said piezo actuator bellows containing a common fluid which is transportable by means of a line system to and into a vertically movable central bellows
Data Source
AI summary
A device and a method for moving an object in a vertical direction are disclosed. The device includes a plurality of piezo-actuators expanding in directions upon activation and in doing so generating pressure forces on an active side, and a hydraulic transmission device that converts the pressure forces of the piezo-actuators into a vertical pressure force for moving the object opposite the direction of gravity and transmits the pressure force with a transmission ratio. The object is lifted after the vertical pressure force has exceeded an oppositely acting spring force of a spring system.