Flexiforce Pressure Sensor
http://www.sparkfun.com/commerce/product_info.php?products_id=8712

This product’s resistance can varies with the amount of pressure applied to it, and it is flexible. We will use several sensors of this type to feed into a control network to regulate the arms.

Arm Design
Asimo from Honda
http://world.honda.com/ASIMO

Asimo is a robot designed by Honda, and its main concept is to operate freely in human living space and to be people-friendly. The introduction of intelligent, real-time, flexible-walking technology allows ASIMO to walk fluidly. Its arms are also capable of human-like fluid movement, which is the hugger needs.