7/30/2019 Transduction Matrix of Electromechanical Driven Work Applying Systems

1/2

Transduction Matrix of Electromechanical Driven Work ApplyingSystems Theory and Applications

The concept of Transduction Matrix of an electro-mechanical actuator was first proposed in 1999 when

trying to develop a method of indirectly measuring actuating force and velocity at the work applying pointin a MEMS (Micro Eletro-Mechanical System). Through 13 years of reserach, the matrix model has beengeneralized into a unique, general and wide-applicable theory for system modeling of a general

mechanical work applying system driven by an electro-mechanical driver.

Basically, Transduction Matrix models the transduction behavior in frequency domain of an actuator

system between the potential and flow variables of its mechanical and electrical terminals. The assumedlinear transformation between F-v (force-speed) coordinates and E-i (voltagecurrent) coordinatesaccurately describes the transduction functions of linear actuators such as piezoceramic drivers. For morenon-linear drivers like AC motors, the accuracy remains engineeringly valid in normal operating ranges.Other than close-form derivation of very simple cases, several numerical and experimental methods arealso available to identify the four transduction functions for a given actuator. Interestingly, thedeterminant of the matrix is confirmed reflecting the efficiency of the energy transformation in the driver,

1 representing energy conservative and the value over 1 signifying energy consumed by heat dissipationin the driver.

Based on the simple model, many creative applications have been developed. These applications include:

1.As the base theory of a new class of sensors. This class of sensors exerts force to the measured objectand senses both of the mechanical excitation and response simultaneously at the force exerting point.

Among more than 10 developments, the moment cum rotary speed sensor and whisker sensor arebreakthrough technologies uniquely addressing historical difficulties in vibration testing and tactilesensing respectively.

2.As a methodology for indrect measurement of the force, speed and impedance at the work exertingpoint of a manufacturing process driven by an electro-mechanical driver. The measurement is doneby only remotely detecting and processing the input voltage and current of the manufacturingsystem. Ultrasonic welding processes like wire bonding, polymer welding are the most studied duringthe past decade.

3. As an enabling technology to make available input impedance of an electromechanically drivenmechanical system the signature for health monitoring and fault diagnosis. Technologies on real-time

in-process quality monitoring of spot welding, arc welding, electric discharging machining, micro-drilling, etc. have been developed.

4.As a simple modeling method quanifying impedance propagation and power transmission in an motordriven electromechanical system in performing mechanical work or carrying load. The model providesa simple and accurate tool to mechanical designers in deciding the driver specs for work performing.

Prepared by: Daniel Digber and Isaac Yeboah Page 1

7/30/2019 Transduction Matrix of Electromechanical Driven Work Applying Systems

2/2

Many other innovative applications are possible. Examples under research include robot-free measurmentof mechanical impedance of human limbs for rehabilitation engineering and sports engineering, friction

measurement of tribological behavior in precision engineering, tools and devices for tactile sensing.Recently, using the model to describe energy harvesting behavior of newly developed micor devices wassuggested by overseas colleagues.

Collaboration and Funding:

In the past 13 years, more than 25 MEng and PhD students and post doctoral fellows in School of

Mechanical and Aerospace Engineering contribute to the development of the theory and specificapplications.

These research projects lead by Professor Ling Shih-fu were financially supported by research grants

from Academic Research Fund (AcRF), A*Star (and NSTB before), Data Storage Institue (DSI),Maritime and Port Authority (MPA), Intelligent System Center (IntelliSys), ST Kinetics, ST Dynamics,PTRC (Protective Technology Research Center) of NTU, DSTA of Misinstry of Defence, JurongShipyard, , etc. Their assistance is much appreciated.

Those interested in commercialing the technologies or further developing in new or more specific

application areas are welcome to contact Prof Ling Shih-fu at msfling@ntu.edu.sg.

Prepared by: Daniel Digber and Isaac Yeboah Page 2

mailto:msfling@ntu.edu.sgmailto:msfling@ntu.edu.sg