Method to extend testing through integration of measured responses virtual models

• US 20050120802A1
• Filed: 12/03/2004
• Published: 06/09/2005
• Est. Priority Date: 12/05/2003
• Status: Active Grant

• Current Assignee: MTS Systems Corporation (Illinois Tool Works Inc.)
• Original Assignee: MTS Systems Corporation (Illinois Tool Works Inc.)
• Inventors: Schulz, Bradley D.
• Granted Patent: US 7,383,738 B2
• Time in Patent Office: Days
• US Class Current: 73/781
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/468 Testing instruments for artificial joints for testing non-implantable prostheses A61F2/76
• CPC Class Codes: A61F 2002/4632 using computer-controlled surgery, e.g. robotic surgery
• CPC Class Codes: G01N 2203/0089 Biorheological properties
• CPC Class Codes: G01N 2203/0246 Special simulation of "in situ" conditions, scale models or dummies
• CPC Class Codes: G01N 3/02 Details
• CPC Class Codes: G01N 3/08 by applying steady tensile or compressive forces G01N3/28 takes precedence

Abstract

A system and method to expand capabilities of simulation and durability testing of a specimen under test utilizing a virtual signal that is generated by combining the actual measured signal from a transducer with a supplemental or simulated signal created by a function based on position, load or another known or measurable parameter. This virtual signal may then be inserted into a control loop to adapt the system to this new, calculated or combined signal.

Claims

1. A system for applying loads to a test specimen, the system comprising:

a controller;

at least one actuator operatively coupled to the controller to operate based on control signals therefrom and adapted to apply loads or control displacement of a test specimen;

at least one load transducer and/or displacement transducer providing signals to the controller indicative of measured loads or displacements on the test specimen; and

wherein the controller is adapted to control said at least one actuator based on signals from at least one load transducer and/or displacement transducer and a representation of additional aspects of the test specimen for generating simulated loads and/or displacements.

2. The system of claim 1 wherein the controller controls the actuator(s) based on input from the load transducer(s) within a predetermined linear operable range.

3. The system of claim 1 wherein the controller includes a representation of additional aspects of the test specimen according to historical measurement data.

4. The system of claim 1 wherein the representation of the controller further comprises multiple parameters whereby more than one actuator may be controlled by the controller based on a single representation.

5. The system of claim 1 wherein the controller comprises more than one representation.

6. The system of claim 5 wherein the stored representations further comprise logical operators in order to engage additional representations.

7. The system of claim 6 wherein the engaging of additional representations by use of logical operators allow uninterrupted test of the test specimen.

8. A method for applying loads to a test specimen, the system comprising:

measuring loads and/or displacements on a test specimen;

controlling at least one actuator coupled to the test specimen to apply selected loads and/or displacements on the test specimen by combining information indicative of the measured loads and/or displacement with corresponding simulated information to produce virtual load and/or displacements that are used to control the at least one actuator.

9. The method of claim 8 wherein controlling by combining information indicative of measured loads and/or displacement with simulated information includes parameters determined through historical data.

10. The method of claim 8 wherein the simulated information includes more than one function.

11. The method of claim 10 wherein the functions further comprise logical operators in order to engage additional functions.

12. The method of claim 11 wherein the additional functions are engaged so as to allow uninterrupted test of the specimen.

13. The method of claim 11 wherein the test specimen is an orthopedic test specimen.

14. An orthopedic test system for applying loads to a test specimen, the system comprising:

a controller;

at least one actuator operatively coupled to the controller to operate based on control signals therefrom and adapted to apply loads or control displacement of an orthopedic test specimen;

at least one load transducer and/or displacement transducer providing signals to the controller indicative of measured loads or displacements on the orthopedic test specimen; and

wherein the controller is adapted to control said at least one actuator based on signals from at least one load transducer and/or displacement transducer and a representation of additional aspects of the orthopedic test specimen for generating simulated loads and/or displacements.

15. The orthopedic test system of claim 14 wherein the controller controls the actuator(s) based on input from the load transducer(s) within a predetermined linear operable range.

16. The orthopedic test system of claim 14 wherein the controller includes a representation of additional aspects of the orthopedic test specimen according to historical measurement data.

17. The orthopedic test system of claim 14 wherein the representation of the controller further comprises multiple parameters whereby more than one actuator may be controlled by the controller based on a single representation.

18. The orthopedic test system of claim 14 wherein the controller comprises more than one representation.

19. The orthopedic test system of claim 18 wherein the representations further comprise logical operators in order to engage additional representations.

20. The orthopedic test system of claim 19 wherein the engaging of additional representations by use of logical operators allow uninterrupted test of the orthopedic test specimen.