Figure 3. Reflex modules of the spinal control layer.

A, 10 reflex modules realize with decentralized feedback key functions of legged systems including compliant behaviour and trunk balance in stance (M₁ to M₅) and ground clearance and leg placement in swing (M₅ to M₁₀). B, schematic contribution of the modules to each muscle's stimulation throughout the gait cycle. The dotted portions indicate modules that are inhibited or excited during double support in proportion to the load F_c on the contralateral leg when transitioning from stance control to swing control. Sw₁ to Sw₄ trigger events within swing control (see text for details).