Workspace analysis of 3SPS+1PS bionic parallel test platform for hip joint simulator

2011 ◽  
Vol 225 (9) ◽  
pp. 2216-2231 ◽  
Author(s):  
G Cheng ◽  
J-L Yu ◽  
S-R Ge ◽  
S Zhang
Keyword(s):  
Hip Joint ◽  
Parallel Manipulator ◽  
Jacobi Matrix ◽  
Parallel Test ◽  
Flexion Extension ◽  
Test Platform ◽  
Moving Platform ◽  
Joint Prostheses ◽  
Hip Joint Simulator ◽  
Orientation Workspace

In order to evaluate the movement performance of a human hip joint, a novel parallel manipulator called 3SPS+1PS bionic parallel test platform is proposed in this article. SPS denotes the spherical-prismatic-spherical leg, and PS the prismatic-spherical leg where only the prismatic joint is actuated and hence underlined. For the 3SPS+1PS bionic parallel test platform with four degrees of freedom including three rotations and one translation, the formulae for solving the inverse kinematics equations are derived based on the quaternion method. Unit quaternion is used to represent the position and orientation of a moving platform, and singularities caused by Euler angles are avoided. Combining the topological structure characteristics of the parallel manipulator, the orientation workspace of the moving platform at a given translation position is constructed. Moreover, the procedures to solve and evaluate the orientation workspace of the parallel manipulator are obtained. In order to ensure dexterity and obtain more workspace, the condition index is studied by the condition number and singular values analysis of the dimensionally homogeneous Jacobi matrix. The parallel manipulator has three rotations about the Z-axis, the Y-axis, and the X-axis applied to represent three rotation motions (flexion/extension (FE), abduction/adduction (AA), and internal/external (IE) rotation motion) of a human hip joint, respectively. The numerical results illustrate that the 3SPS + 1PS bionic parallel test platform generates ±25° to ±108° in FE, −20° to 20° in AA, and −21° to 21° in IE rotation where the maximum permissible condition numbers of Jacobi matrix are set within the range 15–20 and the parallel manipulator can provide full-scale friction motion for hip joint simulator. In the dexterous orientation workspace, the slide track on the friction counterface of hip joint prostheses can be varied consistently. By verifying the lengths of the SPS-type active legs, the parallel manipulator can provide cross-path multidirectional slide motion for hip joint prostheses. The three-dimensional model and kinematics simulation of the manipulator are established and analysed. The simulation results prove that the 3SPS + 1PS bionic parallel test platform can accurately represent human hip joint motion and provide more reliable experimental data for hip joint prostheses in clinical application. The research builds the theoretical basis for its bionic motion simulation in practical application.

Stiffness analysis of the 3SPS+1PS bionic parallel test platform for a hip joint simulator

Robotica ◽  
2013 ◽  
Vol 31 (6) ◽  
pp. 935-944 ◽  
Author(s):  
Gang Cheng ◽  
Jingli Yu ◽  
Peng Xu ◽  
Houguang Liu
Keyword(s):  
Hip Joint ◽  
Stiffness Matrix ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Virtual Work ◽  
Parallel Manipulators ◽  
Parallel Test ◽  
Test Platform ◽  
Global Stiffness Matrix ◽  
Hip Joint Simulator

SUMMARYA novel parallel hip joint simulator, called 3SPS+1PS bionic parallel test platform, with 4 degrees of freedom including three rotations and one translation is designed to represent three-dimensional motion and compound friction movement of a human hip joint and to be a better simulator for testing the tribology performance of biomaterials for hip joint prosthesis. Stiffness is one of the most important performances of parallel manipulators, as well as for the 3SPS+1PS parallel manipulator with higher speeds. First, the differential kinematic/static model was derived based on the kinematics model. The relationship between the elastic deformation of each active leg and the variation of position/orientation deformation of the moving platform was described based on the virtual work principle. Then, a 6 × 6 global stiffness matrix of the 3SPS+1PS parallel manipulator was derived. The maximum versus minimum eigenvalues of the global stiffness matrix were obtained as its two evaluation indexes. By letting the 3SPS+1PS bionic parallel test platform represent three rotation motions and the dynamic loading of the human hip joint as described by ISO 14242 Part-1, the forces acted on each active leg and their responding elastic deformations were analyzed. The distributions for maximum and minimum stiffness in different workspace were detected. Finally, the results showed that the minimum stiffness in the whole workspace should be larger than the allowable stiffness of the 3SPS+1PS parallel manipulator.

Kinematic calibration analysis of 3SPS+1PS bionic parallel test platform for hip joint simulator

Measurement ◽  
2013 ◽  
Vol 46 (10) ◽  
pp. 4152-4160 ◽  
Author(s):  
Gang Cheng ◽  
Xin Yuan ◽  
Jing-li Yu ◽  
Shi-rong Ge
Keyword(s):  
Hip Joint ◽  
Kinematic Calibration ◽  
Parallel Test ◽  
Test Platform ◽  
Hip Joint Simulator

Workspace Optimization of a Six Degrees of Freedom Parallel Manipulator for Micromachining

2010 ◽  
Author(s):  
Ahmet Agaoglu ◽  
Namik Ciblak ◽  
Koray K. Safak
Keyword(s):  
Numerical Analysis ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Base Plane ◽  
Six Degrees Of Freedom ◽  
Moving Platform ◽  
Workspace Optimization ◽  
Kinematic Diagram ◽  
Orientation Workspace

This work addresses the optimization of the workspace of a six degrees of freedom parallel manipulator. In this study, The topology of the manipulator is composed of three xy-tables, symmetrically positioned on a circle on a base plane, connected by three legs to a moving platform. Kinematic composition of the manipulator is introduced and kinematic diagram is illustrated. Orientation workspace is investigated using three different orientation representations. XYZ fixed angles representation is selected considering the benefits of its visualization are considered. By using this representation, the orientation workspace is modeled and kinematic circuits of the manipulator are explored. First, optimization is performed without slider limitations. A result table is obtained based on the user defined parameters. Secondly, optimization is performed under slider limitations. The maximal orientation capability is optimized using numerical analysis. The optimized configuration of the manipulator indicates that a 330% increase in orientation capability is achieved, compared to the old configuration.

Orientation Workspace Analysis of a Novel 3SPS+1PS Symmetrical Parallel Manipulator Based on Unit Quaternion

2011 ◽  
Vol 201-203 ◽  
pp. 1849-1853
Author(s):  
Jing Li Yu ◽  
Gang Cheng ◽  
Shuai Zhang ◽  
De Kun Zhang
Keyword(s):  
Inverse Kinematics ◽  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Unit Quaternion ◽  
Structure Characteristics ◽  
Workspace Analysis ◽  
Moving Platform ◽  
Position And Orientation ◽  
4 Degrees Of Freedom ◽  
Orientation Workspace

For a novel 3SPS+1PS parallel manipulator with 4 degrees of freedom including three rotations and one translation, the formulae for solving the inverse kinematics equations are derived based on quaternion method. Unit quaternion is used to represent the position and orientation of moving platform, and the singularities caused by Euler angles are avoided. Combining the topological structure characteristics of the parallel manipulator, it only has three rotations when its moving platform is at a given translation position. Based on the inverse position/pose equations and the all the constraints of the parallel manipulator, the discrete algorithm for the orientation workspaces of 3SPS+1PS parallel manipulator where the moving platform is at some different given translation positions are designed. The research builds the theoretical basis for optimizing the orientation workspace with given position.

scholarly journals In Vitro Analysis of Wearing of Hip Joint Prostheses Composed of Different Contact Materials

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3805
Author(s):  
Jian Su ◽  
Jian-Jun Wang ◽  
Shi-Tong Yan ◽  
Min Zhang ◽  
Hui-Zhi Wang ◽  
...  
Keyword(s):  
Cost Effectiveness ◽  
Vitamin E ◽  
Femoral Head ◽  
Wear Rate ◽  
Hip Joint ◽  
Cobalt Chromium ◽  
Significant Difference ◽  
Joint Prostheses ◽  
Hip Joint Simulator

Cobalt-chromium-molybdenum alloy (CoCrMo) and ceramic are the two most common materials for the femoral head in hip joint prostheses, and the acetabular liner is typically made from ultra-high molecular weight polyethylene (UHMWPE), highly cross-linked polyethylene (XLPE), or highly cross-linked polyethylene blended with Vitamin E (VEXLPE). The selection of suitable materials should consider both wear performance and cost-effectiveness. This study compared the wear rate between different friction pairs using a hip joint simulator and then recommended a suitable prosthesis based on the corresponding processing technology and cost. All wear simulations were performed in accordance with ISO 14242, using the same hip joint simulator and same test conditions. This study found that when using the same material for the femoral head, the XLPE and VEXLPE liners had a lower wear rate than the UHMWPE liners, and the wear rate of the XLPE liners increased after blending with Vitamin E (VEXLPE). There was no significant difference in the wear rate of XLPE when using a CoCrMo or ceramic head. Considering the wear rate and cost-effectiveness, a CoCrMo femoral head with an accompanying XLPE liner is recommended as the more suitable combination for hip prostheses.

A Three-Axis Hip Joint Simulator for Wear and Friction Studies on Total Hip Prostheses

1996 ◽  
Vol 210 (3) ◽  
pp. 175-185 ◽  
Author(s):  
Vesa O Saikko
Keyword(s):  
Hip Joint ◽  
External Rotation ◽  
Frictional Torque ◽  
Hip Prostheses ◽  
Total Hip ◽  
Flexion Extension ◽  
Single Station ◽  
Wear And Friction ◽  
Total Hip Prostheses ◽  
Hip Joint Simulator

A three-axial, single-station hip joint simulator was designed and built for wear and friction studies on total hip prostheses. The design of the apparatus is described in detail. Continuous level walking is simulated. All three motion components, flexion-extension, abduction-adduction and internal-external rotation, are included. The motions are implemented electromechanically and the uniaxial load pneumatically. The load is measured continuously. For accurate measurement of wear, the apparatus has a loaded control joint, which also renders both the test and control joints self-centring, as they are loaded in series. The frictional torque of the test joint can be measured continuously throughout the wear test, which is an exceptional feature. Four tests of five million cycles each were completed using 32 mm diameter Co-Cr-Mo femoral heads and 5.6 mm thick, metal-backed, ultra-high molecular weight polyethylene acetabular cups as test specimens. Their wear and friction behaviour is described and discussed in relation to previous simulator studies and clinical observations. The lubricant was distilled water, maintained at body temperature. The wear of the cups was measured gravimetrically at intervals. The average wear rate was 3.9 mg/one million cycles, corresponding to 0.03 mm/year, and the average coefficient of friction was 0.01.

Third-Body-Wear as a Risk Factor in Joint Endoprosthetics

2005 ◽  
Vol 284-286 ◽  
pp. 995-998 ◽  
Author(s):  
Thomas Oberbach ◽  
Wilfried Glien ◽  
Christian Kaddick
Keyword(s):  
Hip Joint ◽  
Wear Behaviour ◽  
Third Body ◽  
Ceramic Component ◽  
Joint Gap ◽  
Alumina Particles ◽  
Joint Prostheses ◽  
Hip Joint Simulator

It is well known, that wear of the articulation partners of hip joint prostheses affect the long-term durability of the implants in vivo. The wear is dramatically increased if particles in the artificial joint gap act as third body. Those particles can also occur after a fracture of a ceramic component. Until now there are some different guidelines which coupling (metal-polyethylene, ceramic-polyethylene, ceramic-ceramic) should be used for revision. We tested and compared the wear behaviour of a ceramic-PE-pairing and a ceramic-ceramic-pairing under third body wear conditions with alumina-particles in a hip joint simulator.

Simplified motion and loading compared to physiological motion and loading in a hip joint simulator

2000 ◽  
Vol 214 (3) ◽  
pp. 233-238 ◽  
Author(s):  
S L Smith ◽  
A Unsworth
Keyword(s):  
Hip Joint ◽  
Wear Test ◽  
Test Duration ◽  
Acetabular Cup ◽  
Single Plane ◽  
Wear Rates ◽  
Physiological Loading ◽  
Flexion Extension ◽  
Physiological Motion ◽  
Hip Joint Simulator

Two wear tests were conducted using the Durham Hip Joint Wear Simulator to investigate the effects of simplified motion and loading on ultra-high molecular weight polyethylene (UHMWPE) acetabular cup wear rates. Bovine serum was used as a lubricant and a gravimetric technique was used to measure wear. The first wear test duration was 7.1 × 106 cycles and investigated the effect of simplified loading. This was achieved by using full physiological motion and loading for the first 5 × 106 cycles of the test, then physiological motion with simplified loading for the final 2.1 × 106 cycles of the wear test. The UHMWPE acetabular cup wear rates using full physiological motion and loading were 32.2 and 51.7 mm3/106 cycles against zirconia and CoCrMo femoral heads respectively. Using simplified loading the cup wear rates were 30.1 and 49.2 mm3/106 cycles against zirconia and CoCrMo respectively which was not significantly different from wear rates with physiological loading. The effect of simplified motion was investigated in a second wear test of 5.0 × 106 cycles duration. Physiological loading was applied across the prosthesis with physiological motion in the flexion/extension plane only. Mean wear of the acetabular component dropped to 0.197 mm3/106 cycles. The surfaces of all the actabular cups were subject to gross examination, optical microscopy and scanning electron microscopy. No notable difference was observed between the cups subjected to physiological motion and loading and those subjected to simplified loading. The cups worn with a single plane of motion had a much smaller worn area and a notable difference in surface features to the other cups. Simplifed loading is therefore an acceptable simplification in simulator testing but simplifying motion to the flexion/extension plane axis only is unacceptable.

Sign in / Sign up

Export Citation Format

Share Document