The minimum level of series compliance that adequately protects the transmission from damage during foot collision fails to satisfy bandwidth requirements. As a resolution to this difficulty, parallel motor elasticity is used to lower the forces borne by the SEA, enhancing system force bandwidth. To minimize prosthesis cost of transport (COT) and motor or transmission size, we select a parallel stiffness that supplies the necessary ankle stiffness during early stance period dorsiflexion, eliminating the need for SEA during that gait phase. In future investigations, we hope to apply the ankle-foot design to robotic, orthotic, and exoskeletal applications. In the design of biomimetic ankle-foot systems, we feel both series and parallel motor elasticity are of paramount importance.

Powered ankle-foot prosthesis

Hybrid terrain-adaptive lower-extremity apparatus and methods that perform in a variety of different situations by detecting the terrain that is being traversed, and adapting to the detected terrain. In some embodiments, the ability to control the apparatus for each of these situations builds upon five basic capabilities: (1) determining the activity being performed; (2) dynamically controlling the characteristics of the apparatus based on the activity that is being performed; (3) dynamically driving the apparatus based on the activity that is being performed; (4) determining terrain texture irregularities (e.g., how sticky is the terrain, how slippery is the terrain, is the terrain coarse or smooth, does the terrain have any obstructions, such as rocks) and (5) a mechanical design of the apparatus that can respond to the dynamic control and dynamic drive.

Hybrid terrain-adaptive lower-extremity systems

An exoskeleton worn by a human user consists of a rigid pelvic harness, worn about the waist of the user, and exoskeleton leg structures, each of which extends downwardly alongside one of the human user's legs. The leg structures include hip, knee, and ankle joints connected by adjustable length thigh and shin members. The hip joint that attaches the thigh structure to the pelvic harness includes a passive spring or an active actuator to assist in lifting the exoskeleton and the human user with respect to the ground surface upon which the user is walking and to propel the exoskeleton and human user forward. A controllable damper operatively arrests the movement of the knee joint at controllable times during the walking cycle and a spring located at the ankle and foot member stores and releases energy during walking.

Exoskeletons for running and walking

Biomimetic Hybrid Actuators employed in biologically-inspired musculoskeletal architectures employ an electric motor for supplying positive energy to and storing negative energy from an artificial joint or limb, as well as elastic elements such as springs, and controllable variable damper components, for passively storing and releasing energy and providing adaptive stiffness to accommodate level ground walking as well as movement on stairs and surfaces having different slopes.

Artificial human limbs and joints employing actuators, springs and variable-damper elements

Control systems and methods are disclosed for processing a time series of signals associated with the movement of a device associated with a limb. The time series of motion signals is filtered, such as thorough an autoregressive filter, and compared to stored data sets representing a limb-motion event and/or phase. In certain examples, a plurality of accelerometers generate the time series of motion signals based at least on acceleration measurements in three orthogonal directions and/or planes. The acceleration measurements may relate to the movement of an artificial limb, such as a prosthetic or orthotic device. Upon determining an event and/or phase of limb motion, the control system may trigger an actuator to appropriately adjust one or more prosthetic or orthotic joints.

Systems and methods for processing limb motion

The present invention relates in one embodiment to magnetorheological fluids utilized in prosthetic joints in general and, in particular, to magnetorheological fluids utilized in controllable braking systems for prosthetic knee joints. Preferred magnetorheological fluids of the present invention comprises polarizable iron particles, a carrier fluid, and optionally an additive. Preferred additives include, but are not limited to functionalized carrier fluids as well as derivatized fluoropolymers. Preferred carrier fluids include, but are not limited, to perfluorinated polyethers.

Michael W. Lindsay

Papers

Magnetorheological fluid compositions and prosthetic knees utilizing same