Mechanical stability of the in vivo lumbar spine: implications for injury and chronic low back pain

1. Introduction and Historical Background 1.1 Why make human figure models? 1.2 Historical roots 1.3 What is currently possible? 1.4 Manipulation, animation, and simulation 1.5 What did we leave out? 2. Mody Modeling 2.1 Geometric body modeling 2.2 Representing articulated figures 2.3 A flexible torso model 2.4 Shoulder complex 2.5 Clothing models 2.6 The anthropometry database 2.7 The anthropometry spreadsheet 2.8 Strength and torque display 3. Spatial Interaction 3.1 Direct manipulation 3.2 Manipulation with constraints 3.3 Inverse kinematic positioning 4. Behavioral Control of Articulated Figures 4.1 An interactive system for postural control 4.2 Interactive manipulation with behaviors 4.3 The animation interface 4.4 Human figure motions 4.5 Virtual human control 5. Simulation with Societies of Behaviors 5.1 Forward simulation with behaviors 5.2 Locomotion 5.3 Strength guided motion 5.4 Collision-free path and motion planning 5.5 Posture planning 6. Task-level Specifications 6.1 Performance simulation with simple commands 6.2 Natural language expressions of kinematics and space 6.3 Task-level simulation 6.4 A framework for instruction understanding 7. Epilogue 7.1 A road map toward the future 7.2 Conclusion

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Simulating humans: computer graphics animation and control

The lumbar region is a frequent site of spinal disorders, including low-back pain, and of spinal trauma. Clinical studies have established that abnormal intervertebral motions occur in some patients who have low-back pain. A knowledge of normal spinal movements, with all of the inherent complexities, is needed as a baseline. The present study documents the complete three-dimensional elastic physical properties of each lumbar intervertebral level from the level between the first and second lumbar vertebrae through the level between the fifth lumbar and first sacral vertebrae. Nine whole fresh-frozen human cadaveric lumbar-spine specimens were used. Pure moments of flexion-extension, bilateral axial torque, and bilateral lateral bending were applied, and three-dimensional intervertebral motions were determined with use of stereophotogrammetry. The motions were presented in the form of a set of six load-displacement curves, quantitating intervertebral rotations and translations. The curves were found to be non-linear, and the motions were coupled. The ranges of motion were found to compare favorably with reported values from in vivo studies.

Mechanical behavior of the human lumbar and lumbosacral spine as shown by three-dimensional load-displacement curves

Robotic systems employed in the laboratory, in rehabilitation, and in surgery are reviewed. The advantages of using a robot system over manual procedures in the laboratory to prepare samples is discussed, and some of the obstacles are noted. A typical laboratory robot is described. Rehabilitative applications in the major research areas of tactile sensors, assistive devices for the blind, prosthetics, and orthotics are examined. Manipulators that can help a disabled individual with important everyday tasks and other assistive robotic systems in rehabilitation are described. A variety of robots that assist or perform surgery is surveyed. These applications include positioning in stereotactic neurosurgery, patient manipulation, an in vivo spinal kinematic instrument, and robotic radial keratotomy, among others. >

A literature review: robots in medicine

The Reconfigurable Modular Manipulator System (RMMS) consists of modular links and joints that can be assembled into many manipulator configurations. This capability allows the RMMS to be rapidly reconfigured to custom tailor it to specific tasks. An important issue related to the RMMS is the determination of the optimal manipulator configuration for a specific task. This article addresses the problem of mapping kinematic task specifications into a kinematic manipulator configuration. For the design of two-degrees-of-freedom (2- DOF) planar manipulators, an analytical solution is derived. Because analytical solutions become impractical for problems with more than two design parameters, we have also developed a numerical approach for the design of 6-DOF manipulators. The numerical procedure determines the Denavit-Hartenberg (D-H) parameters of a nonredundant manipulator with joint limits that can reach a set of specified positions/orientations in an environment that may include parallelepiped-shaped obstac...

Kinematic design of serial link manipulators from task specifications

Accessible Region and Synthesis of Robot Arms

The effect of link parameter on the working space of general 3R robot arms

Workspace synthesis of 3R, 4R, 5R and 6R robots

The paper presents the kinematic analysis of motion segments of ten, humanlumbar spines. In order to achieve this objective, a spine fixture and a linkage transducer were designed. The spine fixture is capable of holding the motion segment in a prescribed plane of loading. With the designed fixture it becomes possible to apply three types of shear loads, and three types of bending loads. In addition, if desired, a compressive preload may be applied to a motion segment. The linkage transducer consists of six rotary potentiometers connected by seven rigid links. The transducer is capable of measuring all possible components of vertebral motion. The motion data in the motion segments of ten lumbar spine were collected under the influence of combined shear and bending loads applied in an incremental manner. Maximum shear load was 35.6 N and maximum bending load was 6780 N. mm. The motion segments did not show any appreciable difference in their motion beyond these loads. The motion segments were not subjected to any compressive preload. The range of motion data were collected in twelve loading planes 15 deg. apart. The characteristic vertebral motion may be described in terms of range of motion, its components, and the parameters associated with the screw motion. The paper presents data in the chart form to describe the kinematic characteristics of the lumbar motion segment.

A. H. Soni

Papers

Accessible Region and Synthesis of Robot Arms

The effect of link parameter on the working space of general 3R robot arms

Workspace synthesis of 3R, 4R, 5R and 6R robots

Kinematic Analysis and Simulation of Vertebral Motion Under Static Load—Part I: Kinematic Analysis

A Survey of Cam Manufacture Methods