Development of a General 6-DOF Parallel Robotic System: Load-Control Methodology for Spine Biomechanics Testing

Parallel robots have gained popularity for applications requiring large payloads and accurate multi-degree-of-freedom (DOF) motion. This project focused on the development of a parallel robotic system to examine the injury mechanics of the structures of the lumbar intervertebral joint. Six-DOF position- and load-control algorithms were programmed for machine operation. The positional accuracy of the machine was considered substandard. The kinematic errors were attributed to problems in machine deformation, manufacturing, and assembly. These errors led to poor loadcontrol in porcine lumbar spine tests. A 3-DOF approach improved load-control tests since the other 3-DOF loads were not explicitly controlled. Forces and the principal bending moment were satisfied within ±25N and 1Nm in 6-DOF, and ± 10N and 0.25Nm in 3-DOF. The developed methods are specific to 6-DOF joint testing with parallel robots. The incorporation of these methods into a 6-DOF parallel robot with submillimetre accuracy is warranted for improved multidimensional joint testing

Year	Entry
1980	Adams MA, Stott JRR. The resistance to flexion of the lumbar intervertebral joint. Spine. May–June 1980;5(3):245-253.
1996	Rudy TW, Livesay GA, Woo SL-Y, Fu FH. A combined robotic/universal force sensor approach to determine in situ forces of knee ligaments. J Biomech. October 1996;29(10):1357-1360.
2000	Cripton PA, Bruehlmann SB, Orr TE, Oxland TR, Nolte L-P. In vitro axial preload application during spine flexibility testing: towards reduced apparatus-related artefacts. J Biomech. December 2000;33(12):1559-1568.
2002	Gillespie KA. Biomechanical Role of Lumbar Spine Ligaments in Flexion and Extension Using a Parallel Linkage Robot: A Porcine Model [Master's thesis]. University of Guelph; April 2002.
1984	Yang KH, King AI. Mechanism of facet load transmission as a hypothesis for low-back pain. Spine. September 1984;9(6):557-565.
1982	Schultz A, Andersson G, Örtengren R, Haderspeck K, Nachemson A. Loads on the lumbar spine: validation of a biomechanical analysis by measurements of intradiscal pressures and myoelectric signals. J Bone Joint Surg. June 1982;64A(5):713-720.
1985	Panjabi MM, Krag M, Summers D, Videman T. Biomechanical time-tolerance of fresh cadaveric human spine specimens. J Orthop Res. 1985;3(3):292-300.
1980	Panjabi MM, White AA III. Basic biomechanics of the spine. Neurosurgery. July 1980;7(1):76-93.
1986	Woo SL-Y, Orlando CA, Camp JF, Akeson WH. Effects of postmortem storage by freezing on ligament tensile behavior. J Biomech. 1986;19(5):399-404.
2001	Callaghan JP, McGill SM. Intervertebral disc herniation: studies on a porcine model exposed to highly repetitive flexion/extension motion with compressive force. Clin Biomech (Bristol, Avon). January 2001;16(1):28-37.
1991	Shea M, Edwards WT, White AA, Hayes WC. Variations of stiffness and strength along the human cervical-spine. J Biomech. 1991;24(2):95-107.
1998	Dickey JP. Anatomy and Mechanics of the Human and Porcine Lumbar Interspinous Ligament [PhD thesis]. Queen's University; August 1998.
1970	Farfan HF, Cossette JW, Robertson GH, Wells RV, Kraus H. The effects of torsion on the lumbar intervertebral joints: the role of torsion in the production of disc degeneration. J Bone Joint Surg. April 1970;52A(3):468-497.
1990	Winter DA. Biomechanics and Motor Control of Human Movement. 2nd ed. New York, NY: Inc., John Wiley & Sons; 1990.
1995	Callaghan JP, McGill SM. Frozen storage increases the ultimate compressive load of porcine vertebrae. J Orthop Res. September 1995;13(5):809-812.
1982	Hutton WC, Adams MA. Can the lumbar spine be crushed in heavy lifting? Spine. November 1982;7(6):586-590.
2002	Smit TH. The use of a quadruped as an in vivo model for the study of the spine: biomechanical considerations. Eur Spine J. April 2002;11(2):137-144.
1978	Lin HS, Liu YK, Adams KH. Mechanical response of the lumbar intervertebral joint under physiological (complex) loading. J Bone Joint Surg. January 1978;60A(1):41-55.
1986	McGill SM, Norman RW. Partitioning of the L4-L5 dynamic moment into disc, ligamentous, and muscular components during lifting. Spine. September 1986;11(7):666-678.
1991	Janevic J, Ashton-Miller JA, Schultz AB. Large compressive preloads decrease lumbar motion segment flexibility. J Orthop Res. March 1991;9(2):228-236.
1994	Panjabi MM, Oxland TR, Yamamoto I, Crisco JJ. Mechanical behavior of the human lumbar and lumbosacral spine as shown by three-dimensional load-displacement curves. J Bone Joint Surg. March 1994;76A(3):413-424.
1989	El-Bohy AA, Yang K-H, King AI. Experimental verification of facet load transmission by direct measurement of facet lamina contact pressure. J Biomech. 1989;22(8-9):931-941.
1980	Adams MA, Hutton WC. The effect of posture on the role of the apophysial joints in resisting intervertebral compressive forces. J Bone Joint Surg. August 1980;62B(3):358-362.
1976	Panjabi MM, Brand RA Jr, White AA III. Three-dimensional flexibility and stiffness properties of the human thoracic spine. J Biomech. 1976;9(4):185-192.

Year

Entry

1980

Adams MA, Stott JRR. The resistance to flexion of the lumbar intervertebral joint. Spine. May–June 1980;5(3):245-253.

1996

Rudy TW, Livesay GA, Woo SL-Y, Fu FH. A combined robotic/universal force sensor approach to determine in situ forces of knee ligaments. J Biomech. October 1996;29(10):1357-1360.

2000

Cripton PA, Bruehlmann SB, Orr TE, Oxland TR, Nolte L-P. In vitro axial preload application during spine flexibility testing: towards reduced apparatus-related artefacts. J Biomech. December 2000;33(12):1559-1568.

2002

Gillespie KA. Biomechanical Role of Lumbar Spine Ligaments in Flexion and Extension Using a Parallel Linkage Robot: A Porcine Model [Master's thesis]. University of Guelph; April 2002.

1984

Yang KH, King AI. Mechanism of facet load transmission as a hypothesis for low-back pain. Spine. September 1984;9(6):557-565.