Shape Memory Wire Actuator for Long Endoscopic Probe Steering
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Solution Overview
Problem
Existing endoscopic probes with actuators using pressure fluids or shape memory alloys face limitations such as requiring additional space for fluid lines and heating devices, which complicate design and limit probe length, and are undesirable in certain applications.
Innovation Solution
An actuator using an elongate shape memory wire with electrical conductor, wire insulation, and flexible sheath that converts electrical energy into thermal energy for length change without needing pressure fluids or cooling equipment, allowing reliable shaft head adjustment and small or large diameters without limiting probe length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If actuators operated with pressure fluids are used, then shaft head adjustment is enabled, but additional space for pressure fluid lines is required and device complexity increases
Solution Approach 1:
The patent replaces the pressure fluid actuation system with a shape memory alloy wire-based actuation system. The shape memory wire directly converts electrical energy to mechanical deformation, eliminating the need for pressure fluid lines, pumps, and associated control mechanisms. This substitution reduces the volume required for actuation components while maintaining the shaft head adjustment functionality.
Solution Approach 2:
The patent utilizes the temperature-dependent shape memory effect of the alloy wire, where electrical current changes the temperature parameter of the wire, which in turn changes its length. This parameter-based actuation method eliminates the need for mechanical pressure transmission systems, reducing overall device complexity and volume.
2Ease of operation
If actuators equipped with shape memory alloys and heating devices are used, then shaft head adjustment is enabled, but probe heating above threshold temperature occurs and device complexity increases
Solution Approach 1:
The patent extracts the heating function from a separate heating device and integrates it directly into the shape memory wire itself. The wire serves dual purposes: as the actuation element and as the heating element. This eliminates the need for separate heating devices that would add complexity and potential overheating risks, while maintaining precise temperature control through electrical current regulation.
Solution Approach 2:
The shape memory wire acts as its own heating element, converting electrical energy directly into thermal energy within the wire material. This self-heating capability eliminates the need for external heating devices and associated cooling equipment, reducing device complexity while maintaining temperature control through electrical parameter management.
3Temperature
If cooling devices are added to shape memory alloy actuators, then overheating is prevented, but device complexity and probe diameter increase
Solution Approach 1:
The patent removes the cooling equipment entirely by integrating the heating function directly into the shape memory wire. Without separate heating devices generating excess heat, the need for cooling systems is eliminated. Temperature control is achieved through precise electrical current management rather than active cooling, significantly reducing device complexity.
Solution Approach 2:
The shape memory wire self-regulates its temperature through controlled electrical current input. The wire heats itself to the required temperature for actuation and can be easily cooled by simply interrupting the current flow, eliminating the need for complex active cooling systems while maintaining safe operating temperatures.
4Ease of operation
If pressure fluids and cooling equipment are used, then actuation is achieved, but probe length is limited
Solution Approach 1:
The patent replaces the bulky pressure fluid transmission system with a compact shape memory wire actuation system. The wire can be made extremely thin and flexible, allowing it to be inserted through long, narrow access paths. This substitution enables significantly longer probe lengths while maintaining actuation capability, as the wire requires minimal space compared to pressure fluid lines and associated equipment.
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 actuator provides reliable shaft head adjustment without additional space requirements, enabling small diameter and flexible operation, and avoids heating above a specified threshold temperature, simplifying design and extending probe length.
Implementation Method 1
The shape memory wire is designed such that it converts the electrical energy of the current flowing through it into thermal energy and changes the length of the shape memory wire under the influence of this heat
Implementation Method 2
A shape memory alloy is preferably chosen for this purpose with which any shape memory wire produced using this alloy exhibits the property that it contracts when a specified temperature is exceeded
Data Source
AI summary
The invention relates to an actuator for an endoscopic probe, an endoscopic probe and a method for controlling an actuator of an endoscopic probe. The actuator is provided with an elongate shape memory wire (2) consisting of a shape memory alloy, with an electrical conductor (5) which is electrically conductively connected to the shape memory wire (2) and supplies the shape memory wire (2) with current, with a wire insulation (3) which surrounds at least some sections of the shape memory wire (2) and consists of an electrically insulating material and with a flexible sheath (4) which is pressure-resistant in the longitudinal direction of the shape memory wire (2). The shape memory wire (2) converts the electrical energy of the current flowing through said shape memory wire into thermal energy. Under the influence of this heat, the shape memory wire (2) changes its length from a first length to a second length. The sheath (4) forms a guide for the shape memory wire (2) and a counterbearing for supporting the tensile forces to be transmitted which are effective as a result of the change in shape of the shape memory wire (2).