Method for Regulating the Strain Output of Shape Memory Alloy Actuator

The technology

This invention eliminates the need for position sensors for the fine control of Shape Memory Alloy (SMA) actuators. Nowadays, where precise strain regulation is required, the use of a position sensor is necessary, resulting in additional cost, weight and bulk. A new and highly accurate model for Martensitic Austentitic phase change in Shape Memory Alloy has been developed, and serves as the basis for a new control technique that allows for precise control over actuation. A simple and effective topology for both actuation and control of SMA actuators has been developed and prototyped, enabling low cost control of one or many actuators using a minimum of hardware.

Main advantages

• Eliminates the need for position sensors such as LVDTs
• Maximizes the application scope and potential market for SMA actuators
• Reduces the component count of both the actuator and the controller
• Minimizes cost, weight and bulk of SMA actuator systems
• Implementable within tight space constraints
• Avoids complex control algorithms, such as PI or PID or sliding model
• Easily scalable to multiple actuators with single controller

Commercial potential

This technology may be employed in a wide range of applications where SMA-based actuation is desirable, and where fine position control is a necessity. These applications include, but are not limited to, the following:

• Morphing wing and engine structures
• Helicopter rotor blade angle control
• Artificial muscle in next-generation space and robotic systems
• Actuators for various type of switches and valves
• Dynamic precision control of tension and position in mechanical systems
• Thermostatic drive for smart louvers for satellite thermal control subsystems
• Actuators for tensioning control of membrane synthetic aperture radar (SAR) antennas

The business opportunity

Elimination of bulky and costly position sensors, such as LVDTs, enables much broader application and acceptance of SMA-based actuators. This technology allows for both a cost reduction in existing systems and expansion of the potential market for SMA actuators, thus promoting the adoption of this solution for challenging new applications where this approach may become the preferred technique. A next-generation SMA actuator based on this technology will be a uniquely valuable innovation in many industry sectors.

Technology transfer details

The technology is available for licensing.

The business opportunity may be referred to by its CSA case ID: 50869

Patents

• Canada
  • Number: 2714496
  • Status: Patent Granted
  • Source: Canadian Intellectual Property Office (CIPO)
• United States
  • Number: 8,706,305
  • Status: Patent Granted
  • Source: United States Patent and Trademark Office (USPTO)

Inventors

• Xin Xiang Jiang
• Darius Nikanpour