Ultra-Precision Machine Systems Laboratory

Y. Nakao

Yohichi Nakao

Office: 12-39 Ext.: 3489


01/1997, Ph.D., Tokyo Institute of Technology

03/1988, M.S., Kanagawa University

A. Hayashi

Akio Hayashi
(Assistant Professor)

Laboratory: 12-26 Ext.: 3475


03/2014, Ph.D., Graduate School of Engineering, Kobe University

03/2007, M.S., Kobe University

Research Field

Machine Tools, Precision Engineering, Control Engineering, Water Hydraulics.

Research Overview

Development of ultra-precision machine tools and reducing the energy consumption of machine tools.

Research Subjects

  • 1. Development of water driven spindle and stage.
  • 2. Development of feedback control system for water-driven systems.
  • 3. Development of simulation model for energy consumption of numerical control (NC) machine tools.


The Ultra-Precision Machine Systems Laboratory (UMSL) focuses on the development of state-of-the-art technology for ultra-precision machine systems, including ultra-precision machine tools, their components and control systems. UMSL develops machine tools, manufacturing, and water hydraulics. We focus on high-performance, precise spindle systems and linear/rotary tables. We are also investigating energy reduction strategies for machine tool.

High-performance and precision spindle systems for ultra-precision machine tools

Ultra-precision machining using a single-crystal diamond-cutting tool can create precise parts for advanced technology in areas such as medicine, opto-electronics, and aeronautical engineering. The machining accuracies required are several tens of nanometers or less. Spindles with aerostatic bearings are widely used; however, spindle performance is limited by air compression. UMSL has developed several spindle systems that use water hydrostatic bearings, water-driven mechanisms, and water-cooling. The spindle system shown in Fig. 1 has high-stiffness bearings and a small runout.

Reduction of machine tool energy consumption

Reducing the energy consumption of various facilities is a global concern. In manufacturing, many products are designed by computer-aided design systems and machined by computer-aided manufacturing (CAM) systems and NC machine tools. However, even for products with the same shape, the energy consumption of the machine tool motion is different depending on the tool path generated by the CAM system. UMSL is seeking an effective design strategy for generating optimum tool paths that minimize the energy consumption during machining.

  • 1) “Energy consumption of drive system in NC machine tools during peripheral milling operation,” J. of JSPE, vol. 81(5), pp. 429–434 (2015).
  • 2) “Tool path evaluation based on electric power consumption of feed drive systems in NC machine tool,” J. of JSPE, vol. 80(7), pp. 699–704 (2014).
  • 3) “Feasibility study on design of spindle supported by high-stiffness water hydrostatic thrust bearing,” Intl. J. of Automation Technology, vol. 8(4), pp. 530–538 (2014).
  • 4) “Rotary-type flow control valve for control of fluid-driven spindle,” Trans of JSME, C, vol. 77(774), pp. 514–526 (2011).
  • 5) “Angular position-control of fluid-driven bi-directional motor,” IMechE, Pt. C: J. Mech. Eng. Sci., vol. 224(C11), pp. 2350–2362 (2010).
Affiliated Academic Organizations

Y. Nakao:
The Japan Society of Mechanical Engineers, The Japan Society for Precision Engineering, The American Society of Mechanical Engineers, The Japan Fluid Power System Society, Japanese Society for Artificial Organs.

A. Hayashi:
The Japan Society of Mechanical Engineers, The Japan Society for Precision Engineering.

Current members
◯ Professors: 1 ◯ Assistant Professors: 1 ◯ Postgraduates: 6
◯ Undergraduates: 14