Real felines have impressive claws that can extend with surprising speed to grip objects and attack prey. Retractable claws on a fursuit might not be very functional, but they would be an interesting technology demonstration.

Existing work

Matrices has published a tutorial for retractable claws controlled by the wearer's fingers. Our solution will extend the claws more quickly and allow the wearer to use their fingers normally.

Actuation

There are several possible ways to extend the claws:

• Standard motors or solenoids: All available parts are too big
• Muscle-like actuators: These include shape-memory alloys and super-coiled polymer actuators. These would be perfect, except that they actuate by heating and cooling. To fully actuate, they need to reach temperatures of 100 degrees Celsius or higher. This would not be very safe or comfortable in a fursuit. Also, they can only actuate quickly if they can heat up and cool down quickly. Heating up quickly would use lots of power, and there is no reasonable way to cool an actuator in a paw.
• Pneumatics: A small pneumatic actuator, based on technology from soft robotics research, could extend a claw. The actuator would be fast and relatively small. However, it would be more complex than the electromagnetic options. In addition to the challenges described in the pneumatics research area page, each paw would need a pneumatic connection to the body.
• Custom electromagnetic actuators: A very small rotary solenoid may be a feasible actuator. This currently seems like the most promising avenue.