Hip and knee actuation systems for lower limb orthotic devices

A lower limb orthotic device includes a thigh link connected to a hip link through a hip joint, a hip torque generator including a hip actuator and a first mechanical transmission mechanism interposed between the thigh link and the hip link, a shank link connected to the thigh link through a knee joint, a knee torque generator including a knee actuator and a second mechanical transmission mechanism interposed between the thigh link and the shank link, and a controller, such as for a common motor and pump connected to the hip and knee torque generators, for regulating relative positions of the various components in order to power a user through a natural walking motion, with the first and second mechanical transmission mechanisms aiding in evening out torque over the ranges of motion, while also increasing the range of motion where the torque generators can produce a non-zero torque.