Abstract: A passive prosthetic foot enables a below-knee amputee to walk with near able-body walking motions. The prosthetic foot includes a resilient heel that enables the heel to strike a walking surface more softly than in the prior art and more accurately transition the leg from swing phase to stance phase. The prosthetic foot is modeled generally as a wide Bézier curve, and the foot is characterized according to a set of at least 12 variables, including h, C1d, C2x, C2y, C2d, C3x, C3y, C3d, C4x, C4d, C5d and C6d, where C3y is heel size, C4x is heel geometry and C6d is curve intersection location. The variables are optimized to minimize a difference between a normal lower leg trajectory during gait and a modeled trajectory that includes the prosthetic foot.

Abstract: A prosthesis, including a prosthetic foot, a prosthetic talocrural joint, a prosthetic ankle pivotally coupled to the prosthetic foot and a four-area bending beam. The four-area bending beam includes a U-shaped or other spring. One end of the spring is mechanically coupled via two of the four areas to the prosthetic foot. The other end of the spring is mechanically coupled via the other two areas to the prosthetic ankle. The spring resiliently resists pivoting of the prosthetic ankle about the prosthetic talocrural joint. The four-area bending beam exhibits an at least approximately constant moment along its length to maximize strain energy density, storing about four times as much elastic energy as a comparable cantilevered beam, thereby providing high stiffness and high range of motion to the ankle. The spring is modular, being easily replaced with another spring exhibiting a different stiffness, ex., to tailor the prosthesis to a user.

Abstract: A passive prosthetic foot enables a below-knee amputee to walk with near able-body walking motions. The prosthetic foot includes a resilient heel that enables the heel to strike a walking surface more softly than in the prior art and more accurately transition the leg from swing phase to stance phase. The prosthetic foot is modeled generally as a wide Bézier curve, and the foot is characterized according to a set of at least 12 variables, including h, C1d, C2x, C2y, C2d, C3x, C3y, C3d, C4x, C4d, C5d and C6d, where C3y is heel size, C4x is heel geometry and C6d is curve intersection location. The variables are optimized to minimize a difference between a normal lower leg trajectory during gait and a modeled trajectory that includes the prosthetic foot.

Abstract: A prosthesis, including a prosthetic foot, a prosthetic talocrural joint, a prosthetic ankle pivotally coupled to the prosthetic foot and a four-area bending beam. The four-area bending beam includes a U-shaped or other spring. One end of the spring is mechanically coupled via two of the four areas to the prosthetic foot. The other end of the spring is mechanically coupled via the other two areas to the prosthetic ankle. The spring resiliently resists pivoting of the prosthetic ankle about the prosthetic talocrural joint. The four-area bending beam exhibits an at least approximately constant moment along its length to maximize strain energy density, storing about four times as much elastic energy as a comparable cantilevered beam, thereby providing high stiffness and high range of motion to the ankle. The spring is modular, being easily replaced with another spring exhibiting a different stiffness, ex., to tailor the prosthesis to a user.

Abstract: An apparatus includes a drive shaft, a transmission, a motor shaft, and an engine shaft. The drive shaft includes several drive gears and is used to transmit power to a wheel of a vehicle. The transmission includes a first transmission subassembly and a second transmission subassembly, each subassembly having a transmission shaft, an input gear, and several output gears. Each transmission shaft includes a shifting element to select an output gear. Each transmission subassembly transmits power to the drive shaft when the shifting element of each respective subassembly is engaged. The motor shaft is coupled to a motor and is also directly coupled to the first transmission subassembly via a first motor gear. The motor shaft is also coupled to the engine shaft via a second motor gear. The engine shaft includes several engine gears to couple the engine shaft to the first and second transmission subassemblies.

Abstract: An apparatus includes a drive shaft, a transmission, a motor shaft, and an engine shaft. The drive shaft includes a plurality of drive gears and is configured to transmit power to a wheel of a vehicle. The transmission includes a first transmission shaft including a first transmission input gear and a first plurality of output gears and a second transmission shaft including a second transmission input gear and a second plurality of output gears. The first transmission shaft includes a first shifting element configured to selectively engage an output gear from the first plurality of output gears to adjust a ratio between a shaft rotation speed of the first transmission shaft and a shaft rotation speed of the drive shaft. The second transmission shaft includes a second shifting element configured to selectively engage an output gear from the second plurality of output gears to adjust a ratio between a shaft rotation speed of the second transmission shaft and a shaft rotation speed of the drive shaft.