Table 1 Selected prosthesis characteristics used during CYBATHLON 2016

System voltage

24

VDC

Ankle motor

Maxon EC-4Pole 30

200W

Ankle actuator

130

N/mm

Spring constant (k)

Ankle parallel spring constant

94.20

N/mm

Ankle max torque

130 (@15A)

Nm

Ankle continuous torque

30.6

Nm

(no parallel spring)

Ankle total gear ratio

330:1

Knee motor

Maxon EC-i 40

50W

Knee max torque

∼ 70

Nm

Knee continuous torque

∼ 55

Nm

Knee gear (Planetary) ratio

5.8:1

Knee ball screw lead

2

mm/turn

Knee range of motion

0 to 95

deg

Baseline spring constant (K _BL )

10.7

N/mm (each spring)

Baseline spring mass

19.7

g

Extension spring constant (K _EX )

89.1

N/mm (each spring)

Extension spring mass

15.6

g

Weight acceptance

300

N/mm

Spring constant

Weight acceptance

90

g

Spring weight

Prosthesis overall mass

∼ 5

kg