Project Summary

An investigation will focus on piezoelectric/hydraulic hybrid actuation systems intended for precise displacement, high output force, and rapid response.   Several objectives will be examined associated with the development and understanding of such hybrid actuation systems.  The primary research objectives are as follows.


  1. Design an actuator based on piezoelectric control of hydraulic flow paths.
  2. Develop a closed loop control system for piezoelectric piloted hydraulic actuators.
  3. Create mathematical models of fundamental components for system design and analysis.
  4. Improve mathematical modeling of hybrid actuation systems.


Research Methodology

  1. Design and prototyping will be focused on the development of an amplification module to multiply the displacement of piezoelectric actuators to a usable macro-scale displacement.
  2. Closed loop control will be completed using dSPACE control hardware and Matlab/Simulink, and the integrated “ControlDesk” software.
  3. Models of fundamental components, i.e. piezoelectric actuators, torque blocks, spool valves..., will be created using C++ and transferred to the Virtual Test Bed (VTB).  Within VTB, the model parameters will be variable and configurable to develop virtual systems.  The complete virtual systems can be tested and optimized before producing any hardware prototypes for testing.
  4. Mathematical system modeling and simulation will be completed through the use of software environments including, but not limited to C++, Matlab/Simulink, and VTB.


Shown above is John Brader adjusting the camless engine actuator.

Intellectual Merit and Broader Impact of the Project

  1. A prototype will demonstrate the rapid response, precise displacement, and output force available to such hybrid systems.  The initial target will be to develop an actuator to replace the camshaft in an internal combustion engine.  This type of “camless engine actuator” will allow for infinitely variable valve timing within engines.  This represents a great leap in automotive technology and will allow for greater control of engine power, fuel consumption and reduced emissions. 
  2. Closed loop control of piezoelectric piloted actuators is an advancement over existing systems in such that, existing systems are based primarily on binary input solenoid designs, not the infinite input position of the piezoelectric pilot.  The positioning of a piezoelectric pilot allows for alterations to hydraulic flow paths and thereby volumetric flow rate.
  3. A set of variable models for hybrid actuators will be completed so future prototypes can be tested within the same virtual environment.  This will allow for comparisons among potential hardware designs.
  4. Improvements to mathematical modeling of actuation systems will allow for greater simulation accuracy for complex dynamic system models.


The result of this investigation will be both a physical and virtual actuation system that represents an improved system, and the research will advance the accuracy of dynamic system modeling.

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