Contractile Force and Stitch Modeling of Shape Memory Alloy Knitted Fabric Actuators

Constrained Force Control of Shape Memory Alloy Actuators

Experimental results are presented to show that SMA actuators are able to control forces both rapidly and precisely. An antagonistic pair of constrained actuators is shown to be capable of rapidly changing the setpoint throughout a 7.00 N range. Although the system entered into a limit cycle at the setpoint, the limit cycle magnitude was small. The peak to peak amplitude of the limit cycles was...

Shape memory alloy actuators and their reliability

We have developed two types of shape memory alloy (SMA) actuator and estimated the long-term reliability of SMA microcoils. A tube type tip articulator consists of 4 sets of SMA microcoil (wire diameter: 0.125 mm, coil diameter: 0.5 mm) for driving source and super elastic alloy (SEA) microcoils (wire diameter: 0.1 mm, coil diameter: 0.5 mm) for bias springs, support plates and flexible outer t...

Design and comparison of high strain shape memory alloy actuators

A simulator is developed to model and design high strain shape memory alloy (SMA) tension actuators. The simulator may be used predict characteristics of a given actuator, or to design its geometry under speci cations such as force, speed, stroke and size. The accuracy of the model is veri ed experimentally in reference to an existing NiTi shape memory alloy prototype actuator. Having developed...

Shape Memory Alloy and Elastomer Composite MEMS Actuators

A process for fabrication of shape memory alloy MEMS actuators on a elastomeric polymer substrate is described. These actuators are designed for use on innovative soft body robots. Patterned shape memory alloy (nitinol) is sputter deposited on a polyimide mesh structure. The mesh substrate acts as a bias spring to de-twin the shape memory alloy in the martensite phase. Significant portions of t...

Shape Memory Alloy actuators in robots and composites