Multilayer Electrostatic Actuator With Nonlinear Spring Hardening
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Solution Overview
Problem
Conventional multilayer electrostatic actuators with polymer material sheets or tubes as dielectrics face manufacturing challenges due to the difficulty in placing dogleg or cylindrical structures between electrodes, and they lack nonlinear spring characteristics for efficient stroke and force generation.
Innovation Solution
A multilayer electrostatic actuator design featuring actuator parts with first and second films having patterned connection regions, where the connection regions are arranged to avoid overlap and intersect at a predetermined angle, allowing for soft deformation in a specific drive range and rapid hardening beyond that range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If dogleg or cylindrical structures are used as dielectrics, then large deformation is achieved, but manufacturing difficulty increases
Solution Approach 1:
The dielectric is segmented into multiple thin planar layers instead of using a single dogleg or cylindrical structure. Each layer can be independently manufactured and assembled, simplifying the manufacturing process while collectively achieving the desired large deformation through layered stacking
Solution Approach 2:
The invention transitions from three-dimensional dogleg or cylindrical dielectric structures to two-dimensional planar layered structures. This dimensional reduction simplifies manufacturing while the stacked arrangement of multiple layers compensates for individual layer deformation limits, achieving cumulative large deformation
2Length of moving object
If dogleg or cylindrical structures are used, then large deformation is achieved, but nonlinear spring characteristics are lost
Solution Approach 1:
Different regions of the planar dielectric layers are assigned different functional qualities: connection regions provide structural stability and electrical connectivity, while non-connection regions provide elastic deformation capability. This local differentiation enables the system to exhibit nonlinear spring characteristics with soft deformation in the drive range and rapid hardening beyond that range
Solution Approach 2:
The patent introduces dynamic nonlinear spring characteristics through the interaction between connected and non-connected regions. The connection regions remain relatively rigid while non-connection regions deform elastically, creating a system that transitions from soft to hard behavior as deformation increases, optimizing both stroke and force generation
3Length of moving object
If conventional structures are used, then stroke is extended, but connection portion damage occurs due to stress concentration
Solution Approach 1:
The dielectric is divided into multiple thin planar layers with discrete connection regions, distributing mechanical stress across multiple separation points rather than concentrating it in a single connection portion. This segmentation prevents stress concentration and associated damage while maintaining extended stroke capability
Solution Approach 2:
The use of thin planar dielectric films with patterned connection regions creates a flexible structure that can deform extensively without concentrating stress at connection points. The thin film structure naturally distributes mechanical loads, preventing connection portion damage even during large stroke movements
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
The design achieves suitable nonlinear spring characteristics, providing a sufficient stroke and contraction force within a specific drive range while preventing excessive extension, thus enhancing the actuator's performance and reliability.
Implementation Method 1
when a voltage is applied between first films to generate an electrostatic attractive force, a sufficient contraction force can be secured
Implementation Method 2
the non-connection region (15) is formed having a substantially fixed width between connection regions adjacent to each other as viewed in a layering direction (Z)
Data Source
AI summary
To provide a simply-structured multilayer electrostatic actuator that exhibits a sufficient stroke and a sufficient contraction force in a specific drive range, and rapidly hardens upon an attempt to widen the interval between electrodes beyond the drive range. A multilayer electrostatic actuator (1) is configured by a plurality of actuator parts (2a, 2b, 2c) each including: a first film (3a1, 3b1, 3c1) having a plurality of first connection regions (7a1, 7b1, 7c1) formed on one surface in a predetermined pattern; and a second film (3a2, 3b2, 3c2) connected to the first film via the first connection regions, and having a plurality of second connection regions (7a2, 7b2, 7c2) formed on a surface opposite to the first film in the identical pattern. The actuator parts are connected and layered via the second connection regions. On both the first film and the second film of one actuator part (2a, 2b, 2c), a non-connection region (15) is formed having a substantially fixed width between connection regions adjacent to each other as viewed in a layering direction (Z). The first connection regions and the second connection regions are arranged so as not to overlap each other as viewed in the layering direction. Axes of the patterns between two actuator parts (2a, 2b; 2b, 2c) connected intersect each other at a predetermined angle (θ, except θ=0°) as viewed in the layering direction. When the multilayer electrostatic actuator is pulled in the layering direction due to an external force, the non-connection region, in particular mainly the non-connection region of the second film, is bending-deformed to separate the first film and the second film, resulting in the multilayer electrostatic actuator extending in the layering direction. Further pulling makes the non-connection region tensile-deformed and hardened. When a voltage is applied, the multilayer electrostatic actuator contracts in the layering direction due to the electrostatic attractive force.