“…Creative invention in upper limb prosthetics has not been lacking over the past decade with designs based on a large variety of actuator technologies from conventional dc motors and micromotors [11,12] to more exotic shape memory alloys [11,[13][14][15][16], ultrasonic motors [17], and pneumatic artificial muscles [18][19][20]. Del Cura et al provide an excellent review of these technologies for prosthetic applications, concluding that micro-, ultrasonic, or piezoelectric motors are most promising when compared with hydraulic actuators, shape memory alloys, and contractile polymer gels with regards to size, weight, applicability, precision, hysteresis and non-repeatability, energy consumption, operating frequency, efficiency, power density, anthropomorphism, and cost [9].…”