Piezoelectric Drive Sections with Independent Biasing

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Solution Overview

Problem

Piezoelectric stepper drives face challenges in achieving precise control of the driven member due to inertia, leading to difficulties in accurate advancement.

Innovation Solution

The design incorporates at least two independently drivable piezoelectric drive sections acted upon by two piezoelectric actuators each, with one section biased against the driven member to block its advance in the absence of control voltages, allowing for precise control through coordinated voltage application to reduce or cancel biasing forces and transmit drive forces, enabling high motion resolution and self-locking capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If piezoelectric stepper drive uses traditional drive sections without biasing, then the driven member can move freely, but precise control becomes difficult due to inertia

Engineering Contradiction:

Improvecontrol precisionVSAvoidposition stability

Core Design Contradiction:

Measurement precisionVSStability of the object's composition

Solution Approach 1:

The drive section is pre-biased against the driven member before motion is required. This preliminary biasing force creates a self-locking effect that prevents unintended motion due to inertia, and the biasing force is temporarily reduced or cancelled only when actual drive motion is needed.

Inventive Principle:

Principle #9Preliminary anti-action

Solution Approach 2:

The biasing force applied by the drive section is made dynamically controllable. By varying the biasing force between a locked state (pre-biasing) and an active drive state (reduced or cancelled biasing), the system achieves both position stability and motion control precision.

Inventive Principle:

Principle #15Dynamics

2Stability of the object's composition

If drive sections are biased against the driven member to achieve self-locking, then position stability improves, but energy consumption increases to maintain the biasing force

Engineering Contradiction:

Improveposition stabilityVSAvoidenergy consumption

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The drive section utilizes its own piezoelectric actuator to generate the biasing force required for self-locking. This self-service approach eliminates the need for separate locking mechanisms or continuous energy input to maintain position, as the biasing force is only applied when needed for actual drive cycles.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The biasing force is applied periodically rather than continuously - it is activated during drive cycles to establish self-locking and then reduced or cancelled when the driven member needs to move. This periodic application of biasing force reduces average energy consumption while maintaining position stability during idle periods.

Inventive Principle:

Principle #19Periodic action

3Measurement precision

If multiple piezoelectric actuators are used per drive section to enable independent control, then motion resolution improves, but device complexity increases

Engineering Contradiction:

Improvemotion resolutionVSAvoidactuator configuration

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The drive system is segmented into multiple independently controllable drive sections, with each section having its own piezoelectric actuators. This segmentation allows for fine-grained control of motion resolution while distributing the complexity across modular units that can be independently managed and controlled.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Each drive section is designed as a multi-functional unit that can independently perform both biasing (self-locking) and drive (motion) functions. The piezoelectric actuators in each section serve multiple purposes: applying biasing force for self-locking, generating drive force for motion, and enabling precise position control, thereby reducing overall system complexity through functional integration.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 configuration allows for precise control of the driven member with high motion resolution, energy efficiency, and mechanical stability, reducing unintentional motion and maintaining position without energy consumption when switched off, suitable for applications requiring low power-on times and high temporal and temperature stability.

Implementation Method 1

The motion or deformation of the piezoceramic actuators is based on crystalline effects

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS11101750B2Piezoelectric drive with at least two independent drive sections

Publication Date: 2021.08.24 PHYSIK INSTRUMENTE (PI) GMBH & CO KG

AI summary

A piezoelectric stepper drive includes a piezoelectric drive apparatus with at least two drive sections, each acted upon by at least two piezoelectric actuators, and a driven member which is advanced by at least one of the drive sections when control voltages are applied to the actuators. The drive apparatus is configured approximately in the shape of a triangle, at the tip of which the drive sections are arranged. At least one of the drive sections is biased against the driven member, in the absence of control voltages applied to the actuators, such that the drive section blocks advance of the driven member, where each of the drive sections is mounted individually resilient relative to a base of the triangle.