Abstract: An enhanced mobility wheelchair with semi-autonomous control logic includes criteria for selecting level, stair, and slope modes. Each mode progresses through criteria-invoked phases as the wheelchair travels. Each axis performs an assigned duty for each mode and phase combination to seek a defined target. Control logic invokes stair mode from the level mode when steps are sensed. Criteria restricts negotiating obstacle angles and heights encountered beyond capability and permits reversed travel to exit obstacle. Front and rear support systems include the ability to sense both forward and backward facing steps by adding distance sensors, sensing linkage and rotary sensors. Legrest adjustment raises the feet for forward step climbing and shortens the wheelchair length for tight turns. Steep down slope and steep up slope modes are invoked from a small angle slope mode. Absolute measurement of spider rotation and spider cam engagement does not require adjustment.

Abstract: A self-propelled battery-powered wheelchair replaces an ordinary wheelchair and provides improved access to homes. The wheelchair includes stair climbing, slope climbing, and reclining while requiring only minimal driver skill and strength. Operation on level ground is similar to the operation of a conventional wheelchair. Support for normal operation is provided by a rear caster and wheels on the front corners. Its compact width and length enable negotiating narrow doorways and turning in small spaces. To ensure stability on stairs, moveable skids are mounted to the four corners of the wheelchair. Parallelogram linkages move the front skids down and forward during climbing. Another parallelogram linkage moves the caster and rear skids up and at an angle during climbing. The wheelchair is steerable on stairs as needed to align with the stair path and accommodate slightly spiraling stairs. The wheelchair accommodates stair steps of different riser heights and tread lengths.

Abstract: A wing flap structure includes a wing, a flap, and a hinge mechanism connecting the wing and the flap. The hinge mechanism includes first and second hinge links connected between the wing and the flap. The pivot points for the hinge links are oriented so that as the flap moves away from the wing, the flap moves in a circular arc path relative to the wing. The first hinge link includes a first elongate link having a first end rotatably connected to the wing. The second hinge link includes a second elongate link having a first end rotatably connected to the second end of the first link, and having a second end rotatably connected to the flap. The rotatable connections have axes of rotation that meet at a point below the wing to define an axis of rotation for the circular arc of the flap. The hinge mechanism is contained substantially along the circular arc of the flap as the flap is extended and retracted. A drive mechanism is connected to the wing and to the flap for moving the flap through a circular arc.