Artificial Knee Joints Actuators with Energy Recovery Capabilities: A Comparison of Performance

Table 1

Model parameters of the actuators F-IVT, SEA, and C-SEA. The motor damping parameters and the Coulomb friction torque are not provided by data sheet, but they were estimated following the guidelines given by Maxon.

		F-IVT	SEA	C-SEA
Brushless motor	Model	EC-max 40; 283871	EC 60; 167131	EC 45; 136209
	[mNm]	5.2	0.8	0.77
	[g cm^2]	101	831	209
	[V/rad/s]	0.0628	0.147	0.0739
	[mNm/A]	62.8	147	73.9
	[Ω]	2.02	1.03	1.01
	[Nm/rad/s]
	[A]	—		0.25
	[V]	—		24
Flywheel	[g cm^2]		—	—
IVT		[−1.35, 1.21]	—	—
Gear train		1/50	1/80	1/143
		By model	By model	0.9
Spring	[Nm/rad]	—	375.14	250