Table 1.

An overview of the protocol for each human-in-the-loop optimization case study that attempted to minimize metabolic rate, including the control architecture and device used, the number of parameters (params) in the control architecture, the time spent walking in each control law with a specific parameter set, and the number of control laws per generation (gen). The participants in each case study are also listed, along with their self-selected walking speed and the number of different control laws that were tested during each bout of continuous walking.

control architecture	device	params (#)	time/control law (mins)	control laws/gen (#)	gens (#)	N =	participant	speed (m s−1)	control laws/bout (#)
heel stiffness	3 d.f.	2	2	6	4	1	Sub 1	1.25	2
neuromuscular	1 d.f.	3	2	7	4	1	Sub 2	1.0	7
balance	3 d.f.	2	2	6	4	2	Sub 3	0.89	2
							Sub 4	0.67	3
time-based torque	1 d.f.	5	2	8	6	1	Sub 1	1.25	3
		4	2	8	4	2	Sub 1	1.25	3
							Sub 5	1.25	3
		4	10	8	4	1	Sub 2	1.0	2