Shape Memory Alloy Actuator with Active Cooling Module

Shape Memory Alloy Actuator with Enhanced Response Speed via Water-Cooling and Pneumatic Circulation Module

This technology is a shape memory alloy actuator for surgical robots. It features a coil-type shape memory element that contracts when heated by electrical power, enclosed in a flexible tube to create a flow path. It actively controls heating and cooling by selectively connecting to a coolant circulation system and a high-pressure gas circulation system.

While shape memory alloys have gained attention as drive sources for minimally invasive surgical robots, relying on natural cooling results in slow extension, making precise and rapid repetitive operation difficult. High-efficiency water-cooling methods require large equipment, making them difficult to integrate into small surgical instruments, and residual coolant can delay response times during reheating.

This technology enables rapid heating and cooling by using high-pressure gas from a compressor to push coolant into a reservoir during contraction, and circulating coolant via a pump while cutting power during extension. It maintains a compact module form using an aluminum-deposited bellows heat-dissipation foil tube and temperature sensor-based control. Applicable to neurosurgical and laparoscopic surgical robots and small multi-degree-of-freedom manipulators, it provides high power-to-weight ratios at low noise and cost.

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Key Features:

• A shape memory element with a coil section that contracts when resistance-heated by control power and deforms freely when cooled by power cutoff
• A flexible tube surrounding the coil section to form a flow path, and a pair of connection brackets with inlet/outlet pipes and sealing members
• A first circulation system that circulates coolant using a reservoir and pump, and a second circulation system that discharges coolant from the flow path using high-pressure gas from a compressor
• A control unit that operates the second circulation system and supplies power during contraction commands, and operates the first circulation system and cuts power during extension commands

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This invention was developed with support from the Ministry of Education for the development of soft robot deformation and stiffness control technology for avatar-type disaster rescue robots.

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