MIMO Shaker Systems
Multiple-Input Multiple-Output Shaker Systems
There are many different types of multiple shaker table arrangements based on MIMO vibration testing applications. Multi-Exciter Single-Axis (MESA), is an application in which multiple exciters provide dynamic input to a test item along a single axis. For cases in which the two exciters are driven to a common specification with respect to both phase and amplitude, the output may be described basically in one axis of excitation. For cases in which the two exciters are driven to independent magnitude and/or phase specifications, the output may need to be described in terms of a forward axis and aft axis, and perhaps, a rotational axis about the test item’s center-of-gravity (CG).
Note that the system would require appropriate bearing assemblies to allow a pure rotational MESA or combined linear and rotational motion. The following photo illustrates a dual shaker vertical push-push arrangement.
Three axis shaker tables are available for Multiple-Exciter Multiple-Axis (MEMA) vibration test arrangements. Many vibration testing applications require testing the DUT in simultaneously all three directions. With a three-axis shaker table system, the overall testing time is reduced by two-thirds over single-axis vibration testing along each axis. More importantly, it identifies failures otherwise undetected with single-axis vibration testing.
The automotive industry has been running tests on their vehicles for decades using four poster testing systems. Nowadays, with the availability of sophisticated MIMO control, vibration testing with four posters is raised to another new level. The time waveform recorded from the testing tracks or real road conditions can be accurately reproduced inside the lab.
The vibration environment is incomplete without rotation. The MEMA Type 6 DOF Shaker Tables are available for these types of testing. The arrangement of shakers among all three axes allows the row, pitch, and yaw to be achieved along with the three-dimensional translation motions from the table.
The following six-DOF testing table consists of eight electro-dynamic shakers arranged along all three directions. Four shakers under the table will provide the excitation along the vertical axis translational motion together with the roll and pitch rotational motion. The four shakers, with two along each horizontal direction, will excite the table to generate transverse and longitudinal translational motion, as well as yaw rotational motion.
Continuous Data Recording
During vibration testing, all measurement input and drive signals can continuously record to a Spider-NAS or the internal storage residing in each front-end. Users can view and analyze data files with Crystal Instruments Post Analyzer. The variable sampling rate can be enabled to simultaneously record slow-change signals together with high speed vibration data.
Monitoring Through EDM Cloud
All vibration tests in EDM-VCS support status checks through EDM Cloud. With EDM Cloud support, users can set up any VCS test to upload live data or run logs for completed tests to a cloud storage space provided by Crystal Instruments, where data is securely stored in the user’s account.
The EDM Cloud website is located at https://cloud.go-ci.com. Users can access EDM Cloud from anywhere in the world to check the status of past and current tests. A secure login flow ensures the status can only be checked by authorized personnel with proper credentials. Multiple logins for accessing the same Cloud account is available.
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Vibration Utilities App
Crystal Instruments in partnership with our sister shaker company Sentek Dynamics provides users with the Vibration Utilities mobile app on iOS and Android. This app provides calculation features for sizing your vibration profile (Random, Sine or Shock) and searches through our catalogue of shakers and controllers for the best fit.
