Multi-Spring Actuator Layout for Force-Stroke Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing actuators, such as DE and SMA actuators, either generate large strokes with moderate force or small strokes with large force, but not both effectively, and often require a fixed abutment which leads to bearing forces and limited energy utilization.
Innovation Solution
The actuator employs at least two restoring means, such as snap springs and helical springs, to create a tailored total restoring means characteristic curve, allowing for energy storage and efficient movement from an initial to a working position without a fixed abutment, enabling both large strokes and forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single restoring means is used in DE or SMA actuators, then the structure is simple, but the force-stroke characteristics cannot be optimized for both large stroke and large force simultaneously
Solution Approach 1:
The restoring means is divided into multiple independent spring elements (first and second spring elements) with different characteristics. Each spring element contributes a portion to the total restoring force, allowing the system to achieve both large stroke and large force by combining their individual force-displacement characteristics.
Solution Approach 2:
Multiple spring elements are combined in parallel to create a composite restoring means system. The combined system merges the advantages of individual springs with different characteristics, producing a total restoring force that maintains high magnitude across the entire stroke range, thereby achieving both large displacement and large force simultaneously.
2Stability of the object's composition
If a fixed abutment is used in actuators, then the structure is stable, but bearing forces occur and energy utilization is limited
Solution Approach 1:
The fixed abutment is removed from the actuator system. Instead of relying on a stationary reference point, the actuator uses floating support elements that move with the actuator element, eliminating the generation of bearing forces and improving energy utilization by allowing the entire system to move freely.
Solution Approach 2:
The support structure transitions from a static fixed abutment to dynamic floating support elements that move together with the actuator element. This dynamic configuration eliminates rigid constraints, prevents bearing forces, and maximizes energy efficiency by allowing the system to move without energy loss to friction and bearing resistance.
3Length of moving object
If DE actuator design is used, then large stroke is achieved, but force generation is moderate
Solution Approach 1:
Multiple spring elements with different force-displacement characteristics are combined to create a composite restoring force that maintains high magnitude across the entire stroke range. This merging of spring characteristics allows the actuator to achieve both the large stroke capability of DE actuators and enhanced force generation throughout the motion.
4Force
If SMA actuator design is used, then large force is achieved, but stroke is small
Solution Approach 1:
The restoring means is segmented into multiple spring elements that provide restoring force at different stages of the stroke. This segmentation allows the system to extend the effective stroke while maintaining high force levels, as each spring element contributes to the total force at different displacement ranges, thereby achieving both large stroke and large force.
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 ensures uniform force or stroke generation over the entire movement, maximizing energy use and preventing transverse forces, making it suitable for applications like robotics.
Implementation Method 1
energy can be stored by the restoring means, which is available for movement out of the basic position into the working position or an end position and which can be used to generate a large stroke and/or a large force
Implementation Method 2
an actuator element formed as a foil-shaped dielectric elastomer (DE actuator) which is connected in series with a single restoring means
Implementation Method 3
Shape memory alloys are mechanically deformable and can return to an undeformed initial state by heating, for example by application of an electric current
Data Source
AI summary
The invention relates to an actuator (1; 1a; 1b) which can be moved from an initial position into a working position having at least one actuator element (2; 2a; 2b) whose dimensions can changed by an electrical signal, Appropriately, at least two restoring means (20, 30; 20a, 30a; 20b, 30b) acting on the actuator element (2; 2a; 2b) are provided for movement into the working position. With the at least two restoring means, a total restoring means characteristic curve, which is composed of portions of the individual, preferably preloaded restoring means as well as a portion of a variable stiffness of the actuator element, can be advantageously tailored.