Mechatronics Laboratory


Vibration measurement and control

Vibration isolator with nanomter resolution
[Ito et al., Ultramicroscopy, 186]

Vibrations are one of the main factors that limit performances of high-quality mechatronic systems, such as manufacturing systems, data storage devices, and imaging systems. While vibrations can be transmitted through the floor as an external disturbance to a system, they can be internally induced, for example by actuation forces in the case of motion control systems.

To measure problematic vibrations for compensation, especially at low frequencies, vibration sensors are under development to broaden their measurement bandwidth and minimize the size by utilizing the interaction between the mechanical and electrical design. Such a sensor and a displacement sensor are utilized for vibration control, for example in the form of a vibration isolator.

Atomic force microscopy

Large-range AFM
[Ito et al., IEEE TIE, 68(1)]

Atomic force microscopes (AFMs) use a probe with a sharp tip for both imaging and manipulation of samples and objects with nanometer resolution. AFMs are typically designed with a tradeoff between the workspace and the throughput.

To overcome the current tradeoff for a workspace of more than 100 micrometers with a high control bandwidth, we develop AFMs with electromagnetic actuators. This research has a potential for real-time nanoscale imaging of a sample in an environment that significantly changes the sample volume, such as ones under thermal testing and stress testing.

Next-generation actuators and their advanced control

High-precision reluctance actuator
(cf. [Ito et al., IEEE TIE, 66(4)])

For a relatively large range of more than a hundred micrometers, voice coil actuators are mostly used for motion control with nanometer resolution. To achieve a higher actuation force for high-speed motions in an energy efficient way, the reluctance force is utilized to develop high-precision actuators such as reluctance actuators and hybrid reluctance actuators. They can achieve a motor constant that is four times larger than comparable voice coil actuators. Such actuators can be combined with linear motors as a dual stage actuator for long-stroke motions with nanometer resolution.

Control of the next-generation actuators is another crucial research topic to fully utilize their potentials for industrial application. Particularly, research on learning control is ongoing to realize high-speed and high-precision motions, for example for AFM and laser processing. The aim of the learning control is to be operated onsite, such that the highest motion performance is always acquired, despite model uncertainties due to environments.