No abstract

A prototype active Ankle Foot Orthosis has been developed to control and assist plantar flexion and dorsiflexion using an innovative series elastic actuator integrated into a standard passive AFO. A motor controls the moment arm (Insertion Point Eccentricity Control or IPEC) of a pretensioned spring, and though the magnitude of the spring force remains relatively constant, the changing moment arm produces torque about the ankle. The IPEC AFO is able to provide 3.51 Nm about the ankle in dorsiflexion and 3.88 Nm in plantar flexion with a spring modulus of 3110 N/m and an initial tension of 77 N. The torque was sufficient to prevent toedrag during swing phase. This technology may benefit users with drop-foot or other ankle disorders, including those who have suffered stroke or spinal cord injury.

A device reminiscent of the mammalian spine has been designed and built with the ability to lock each individual joint in a string of ball joints. The assembly may be controlled in a manner similar to other hyper-redundant robots, with the added advantage of locking in a straight or axial position. Locking is achieved by orienting two mating collars in a singular configuration that forces compression against neighboring collars and prohibits bending or rotation. Locking is desirable for added strength in supporting objects, as well as for stabilization and power efficiency when bending is not necessary. The split locking mechanism represents a biologically inspired structure with added strength and stability for use in robotics.

A traditional spinal orthosis in conjunction with a hip-knee-ankle-foot orthosis (HKAFO) improves posture in persons with paraplegia during standing and walking. It also limits the wearer's range of motion when worn during other activities, such as vehicle transfer or sitting and reaching for objects. In order to regain full torso flexibility the user would need to remove the spinal orthosis which can be arduous and time consuming. A Convertible Spinal Orthosis (CSO) that allows the user to switch between Locked rigid torso support and Unlocked free motion has been designed, fabricated and tested. It shows promise for increasing functionality, wear time and subject comfort. Analysis of movement has been performed with an able-bodied and a paraplegic subject wearing a rigid spinal orthosis, the CSO in both states, and without any bracing. Configuration state had the most impact on lateral bending. Mean values for the paraplegic subject of 27 • , 38 • , 48 • , and 48 • and for the able-bodied subject of 22 • , 26 • , 48 • , and 45 • were found for lateral bending of the upper torso relative to the thighs in the Rigid, Locked, Unlocked, and No-Brace states, respectively.