The design and prototyping of a vestibular stimulation device

Stimulation of the vestibular system (inner-ear balance center) has been proposed as a major therapeutic tool for the treatment of children and adults with neurological disabilities. Numerous studies have attempted to establish its value and, in practice, different forms of the therapy are being used by occupational and physical therapists in the treatment of individuals with these disabilities. There have however, been only limited systematic investigations of the value of different forms of vestibular movements and their clinical results. A major drawback to such research is the lack of a well designed research tool. This thesis discusses the design, construction and testing of such a device and is presented as a masters thesis in Mechanical Engineering, Machine Design emphasis. The device may rotate the patient on three independent axes. By a rotation of one of these axes the patient may be pitched forward and back, rolled from side to side or spun about a vertical axis. The patient is rotated about the center of gravity of the patient/machine system. This situation results in very low torque requirements at each of the device joints. By simultaneous rotations of the three machine axes the patient may be rotated about any desired axis. Computer controlled stepper motors drive each of the three axes. This drive system allows for precise and programmable control of the motion. Each joint is driven by the stepper motor through a custom designed worm gear reduction. Aluminum castings were designed and fabricated to house the worm gears selected. The patient is seated in a TUMBLE FORMS brand carry seat that provides positive patient positioning and restraint. A fiberglass enclosure prevents the patient from any possible contact with the machine joints or foundation. The machine joints and foundation are fabricated from extruded aluminum tube. This thesis discusses the methodology of the design of the device. A design overview, prototype design and construction, assembly instructions, performance testing and cost analysis of the prototype, and recommendations for future models are presented.