Noliac Ring Bender in a New Piezo Servovalve

A research from the University of Bath, UK, describes a new two-stage aerospace servovalve. The purpose of the research is to design a low-weight servovalve with low leakage and more accurate spool positioning. The servovalve uses a Noliac piezoelectric ring bender.

Kvistgaard, Denmark, September 08, 2016 --( Promising piezoelectric servovalve prototype

A group of researchers from the Centre for Power Transmission and Motion Control at the University of Bath, UK, has cooperated with with an aircraft control systems manufacturer to design a new piezoelectric servovalve for aerospace. Servovalves control the flow of hydraulic fluid to actuators on aeroplanes. The research describes a new two-stage servovalve with a titanium body, and a small piezoelectrically actuated spool as its first stage with electrical main stage position feedback. This piezoelectric servovalve prototype provides low weight, low leakage, and more accurate spool positioning. In addition, it enables increased manufacturing automation thereby reducing cost, increasing repeatability, and generates less waste material.

Andrew Plummer, Director of the Centre for Power Transmission and Motion Control at the University of Bath, is satisfied with the result of the prototype. He explains, "The research and prototype has been very promising. We are happy that the design of the piezoelectric servovalve has met the functional requirements. The piezoelectrically actuated first stage works very well and ensures low leakage, which improves the efficiency of the servovalve. In addition, we are pleased that the durability of the prototype has enabled a range of performance and reliability testing to be undertaken. Further development is required before commercialization is possible, however, it seems like this approach is worth pursuing," Andrew Plummer concludes.

The research paper "Lightweight, Low Leakage Piezoelectric Servovalve" was published in connection with the conference Recent Advances in Aerospace Actuation Systems and Components, March 16-17, 2016, Toulouse, France.

The research paper can be found at

Noliac piezo ring bender drives the spool

The piezoelectric two-stage servovalve is constructed with a small spool that is directly driven by a Noliac piezoelectric ring bender actuator. The ring bender CMBR07 was chosen due to the high level of displacement. A ring bender is a multilayer actuator generating a bending mode when voltage is applied. Noliac offers a range of ring benders in different sizes and performances, e.g. displacement up to +/- 185 µm. The ring bender can be customized to match specific requirements.

It is possible to learn more about the Noliac ring benders at

External research publications mentioning Noliac

Noliac has collected external research publications, where Noliac or Noliac products are mentioned. The diversity of the publications show just how widespread the use of piezo technology is. Similar research publication can be listed on Noliac's website, if they are emailed to

The list of external publications can be found at

More information?

If you want to know more about Noliac’s piezo bending actuators or any other Noliac product, please contact us using our Request for Quote or contact sales.
Noliac A/S
Lotte Beck
Hejreskovvej 18
DK-3490 Kvistgaard