Multiple Input - Multiple Output
JAGUAR recreates multiple degree of freedom environments in the laboratory. Applications as diverse as shaking a portable computer in 3 axes simultaneously, driving a very heavy structure in one axis while sharing the load over many shakers, or even recreating 6 DOF movement at each of the four wheels of an automobile may now be accomplished with JAGUAR MIMO applications.
Many control systems purporting to be multi-shaker controllers simulate Random and Swept Sine excitation from time data replication. This approach is statistically inaccurate. JAGUAR MIMO produces true Random with one control per actuator or averaged control points per actuator. The same quality of control offered by MISO Random is inherent to MIMO Random control. Adaptive control guarantees rapid equalization and accurate control in the face of non-linear response. It also reduces the time required to achieve full level testing, which reduces the exposure to low level energy for the test article. MIMO Random assures accurate tests while uncoupling the shaker responses from each other and the governing phase.
MIMO Sine, like MIMO Random, controls phase between actuators and between axes.
By maintaining a three dimensional impedance matrix, JAGUAR is always capable of determining the contribution from each shaker to the overall response and properly differentiating for each actuator so that proper, accurate, safe control is assured. The complex issue of singularities is addressed with an elegant solution that permits intricate tests to be performed without having to resort to test segmentation in an attempt to avoid the singularity.
JAGUAR ’s MIMO suite of capabilities includes both short duration Transient Waveform Control (TWC)appropriate for replicating many transient and seismic events and indeterminate duration waveforms (Waveform Replication)typically used to replicate automotive style durability tests. Older style solutions do not update the system H(f)during the output phase of the loop. JAGUAR uses a real-time compensation technique that permits automatic adjustments to the system ID as the measured response changes. This feature ensures optimum safety and accuracy for your test. It also reduces equalization time, speeding the actual test process and minimizing low level exposure for the test article.
MIMO Technical Specifications - click to expand
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Published MIMO Reference Documents Written by Spectral Dynamics Engineers
1. Keller, Tony and Underwood, Marcos A.; “An Application of MIMO Techniques to Satellite Testing”; Presented at ESTECH 2000, May 3, 2000 in Newport, Rhode Island.
2. Underwood, Marcos A. and Keller, Tony; “Rectangular Control of Multi-Shaker Systems; Theory and Some Practical Results”. Proceedings of the Institute of Environmental Sciences and Technology, ESTECH2003, May 19, 2003, Phoenix, Arizona, USA.
3. Underwood, Marcos A. and Keller, Tony; “Applying Coordinate Transformations to Multi Degree of Freedom Shaker Control”; Proceedings of the 74th Shock & Vibration Symposium; October, 2003; San Diego, CA, USA.
4. Keller, Tony; “Some Aspects of Multi-Shaker/Multi-Axis MIMO,” Proceedings – 13th Japan Group Meeting on Human Response to Vibration, Osaka, Japan, August, 2005.
5. Maeda, Setsuo and Keller, Tony; “Multi-Axis Hand/Arm Vibration Testing and Simulation at the Japan National Institute of Occupational Safety and Health;” First American Conference on Human Vibration, June 5-7, 2006, Morgantown, West Virginia, USA.
6. Keller Tony; Maeda, Setsuo and Shibata, Nobuyuki; “A Rationale’ for 3-Axis Hand/Arm and Whole Body Vibration Simulation”, 14th Japan Conference on Human Response to Vibration, Kawasaki, Japan, August 2-4, 2006.
7. Underwood, Marcos A. and Keller, Tony., “Understanding and using the Spectral Density Matrix,” Proceedings of the 76th Shock & Vibration Symposium, October, 2005, Destin, Florida, USA.
8. Underwood, Marcos A. and Keller, Tony., ”Using the Spectral Density Matrix to Determine Ordinary, Partial and Multiple Coherence”, Proceedings of the 77th Shock & Vibration Symposium, October, 2006; Monterey, California, USA.
9. Ayres, Russell, “Motion Control in Multiple Dimensions”; A Tutorial presented at the 77th Shock & Vibration Symposium, October, 2006, Monterey, CA.
10. Keller, Tony; Maeda, Setsuo and Shibata, Nobuyuki; “Hand-Arm Vibration Test Bench”; Proceedings of the 11th International Conference on Hand Arm Vibration, Bologna, Italy; June 3-7, 2007.
11. Underwood, Marcos and Keller, Tony; “On Using Response Limiting Control During Multi-Shaker Testing”; Proceedings of the 78th Shock & Vibration Symposium, November 4th – 8th, 2007; Philadelphia, Pennsylvania, USA.
12. Underwood, Marcos A.; Ayres, Russell and Keller, Tony; “Creating and Controlling Unusual Waveforms for Multi-Shaker Testing”; Proceedings of the 79th Shock & Vibration Symposium, October 26th – 30th, 2008; Orlando, Florida, USA.
13. Hale, Michael and Underwood, Marcos A.; “MIMO Testing Methodologies”; Proceedings of the 79th Shock & Vibration Symposium, October 26th – 30th, 2008; Orlando, Florida, USA.
14. Lamparelli, Marc; Underwood, Marcos; Ayres, Russell and Keller, Tony; “An Application of ED Shakers to High Kurtosis Replication”; ESTECH2009, The 55th Annual meeting of the IEST, May 4-7, 2009; Schaumburg, Illinois, USA.
15. Underwood, Marcos A.; Ayres, Russell and Keller, Tony; “Filling in the MIMO Matrix; Using Measured Data to run a Multi-Actuator/Multi-Axis Vibration Test”. Presented at the 80th Shock & Vibration Symposium, October 26th – 29th , 2009 San Diego, California, USA.
16. Underwood, Marcos A.; Ayres, Russell and Keller, Tony; “Considerations in Using Field Data for Multi-Shaker Time Waveform Replication Testing”; Presented at the 81st Shock & Vibration Symposium, October 24th – 28th , 2010 Orlando, Florida, USA.
17. Underwood, Marcos A., Ayres, Russell and Keller, Tony; “Creating MDOF Test Formulations While Maintaining Positive Definite Characteristics”. Presented at the 82nd Shock & Vibration Symposium, October 30 – November 3, 2011, Baltimore, MD.
18. Underwood, Marcos and Keller, Tony; “8 Actuator System provides 1 DOF to 6 DOF Controlled Satellite Qualification Testing to 100Hz”; Presented at the Aerospace Testing Symposium, March 25 – 27, 2014 at the Renaissance LAX Hotel, Los Angeles, CA.
19. Underwood, Marcos and Keller, Tony; “Applications of MIMO Coherent Output Power Analysis to Multi-Shaker Testing”; Presented at the 85th Shock & Vibration Symposium, October 26 – 29, 2014, Reston, VA.
20. Underwood, Marcos and Keller, Tony; “Applications of Digital Control Techniques to High Level Acoustic Testing”; Presented at ESTECH2015, April 27 – 30, 2015, Danvers, MA, USA
21. Underwood, Marcos; “The Use of Quaternions to Compensate for Geometric Distortion in Dynamic Seismic and Satellite Testing”; Presented at the 29th Aerospace Testing Seminar, October 28, 2015, Los Angeles, CA
22. Underwood, Marcos A., Ayres, Russell and Keller, Tony; “Multi-Shaker Control: A review of the Evolving State-of-the-Art”. Presented at ESTECH2016, May 2 - 5, 2016, Glendale AZ.
23. Underwood, Marcos A., Ayres, Russell and Keller, Tony; “Advances in MIMO Testing over the past 2 Decades; From MIL-STD-810G to a Recommended Practice, RP, DTE-022. Presented at the 87th Shock & Vibration Symposium, October 17 – 20, 2016, New Orleans, LA.
24. U S Patent No. 5,299,459 (Apr 1994) “Adaptive Control Method and System for Multi Exciter Swept-Sine Testing” – E U Patent # 0521853
25. U.S. Patent No. 5,517,426, Adaptive Control Method and System for Transient Waveform Testing, May 14, 1996.
26. U.S. Patent No. 4,937,535, Calibration Method and Programmable Phase-Gain Amplifier Circuit, June 26, 1990.
27. U.S. Patent No. 4,782,324, Digital Signal Synthesizer Method and System, November 1, 1988. 28. Underwood, Marcos A.; “Application of Digital Computers”, Chapter 27 of Shock and Vibration Handbook, 5th ed., Edited by Harris, C. M., and Piersol, A. G., New York, McGraw Hill, 2001;
29. Underwood, Marcos A.; “Digital Control Systems for Vibration Testing Machines,” Chapter 26 of Shock and Vibration Handbook. 6th ed., Edited by Piersol, A.G., and Paez, T.L., 2009, New York, McGraw-Hill.
30. Underwood, Marcos A. “Applications of Digital Control Techniques to High Level Acoustic Testing”. Presented at the 31st Aerospace Testing Seminar, October 23 – 25, 2018, Renaissance Los Angeles Airport Hotel, Los Angeles, CA.
31. Underwood, Marcos A.; “Applications of MIMO Digital Adaptive Control to High Level Acoustic Testing”. Presented at the 26th International Congress on Sound and Vibration, 7 – 11 July, 2019, Montreal, Canada
