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Query: UMLS:C0700208 (scoliosis)
 8,574 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In 322 cases of lumbar PID proved by myelography the radiologically recognizeable malalignment of the lumbar spine was related to site and direction of the prolaps. Scoliosis towards the side of the prolapse was seen in about 70 per cent. Scoliosis convex towards the normal side was significantly more common with right-sided than with left-sided prolapses. Scoliosis was the more pronounced the higher the site of prolapse. The degree of lumbar lordosis, too, appeared to depend on the level of prolapse. The lower the prolapse the less the lordosis. In the individual case one cannot draw any conclusions as to site or direction of a prolapse from radiologically detectable malalignment.
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PMID:[Malalignment of lumbar spine with lumbar PID (author's transl)]. 12 47

Robotic spine brace based on parallel-actuated robotic system is a new device for treatment and sensing of scoliosis, however, the strong dynamic coupling and anisotropy problem of parallel manipulators result in accuracy loss of rehabilitation force control, including big error in direction and value of force. A novel active force control strategy named modal space force control is proposed to solve these problems. Considering the electrical driven system and contact environment, the mathematical model of spatial parallel manipulator is built. The strong dynamic coupling problem in force field is described via experiments as well as the anisotropy problem of work space of parallel manipulators. The effects of dynamic coupling on control design and performances are discussed, and the influences of anisotropy on accuracy are also addressed. With mass/inertia matrix and stiffness matrix of parallel manipulators, a modal matrix can be calculated by using eigenvalue decomposition. Making use of the orthogonality of modal matrix with mass matrix of parallel manipulators, the strong coupled dynamic equations expressed in work space or joint space of parallel manipulator may be transformed into decoupled equations formulated in modal space. According to this property, each force control channel is independent of others in the modal space, thus we proposed modal space force control concept which means the force controller is designed in modal space. A modal space active force control is designed and implemented with only a simple PID controller employed as exampled control method to show the differences, uniqueness, and benefits of modal space force control. Simulation and experimental results show that the proposed modal space force control concept can effectively overcome the effects of the strong dynamic coupling and anisotropy problem in the physical space, and modal space force control is thus a very useful control framework, which is better than the current joint space control and work space control.
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PMID:Design and implementation of a novel modal space active force control concept for spatial multi-DOF parallel robotic manipulators actuated by electrical actuators. 2906 87