High-precision Actuators Research Articles

Three-axis lever actuator with flexure hinges for an optical disk system

A three-axis lever actuator with a flexure hinge has been designed and fabricated. This actuator is driven by electromagnetic force based on a coil-magnet system and can be used as a high precision actuator and, especially as a pickup head actuator in optical disks. High precision and low sensitivity to external vibration are the major advantages of this lever actuator. An analysis model was found and compared to the finite element method. Dynamic characteristics of the three-axis lever actuator were measured. The results are in very close agreement to those predicted by the model and finite element analysis.

Test Bed Development for Research on Performance of High Speed Vessels

Self-propelled ship models are presented. The first model can run autonomously using an embedded controller (based on a 16-bit microcontroller). Typical manoeuvres as the turning test and the “zigzag” were carried out. Navigation is based on an electronic compass. Propulsion and steering are performed through high precision actuators. Simultaneously, a more sophisticated system is being assembled and tested at the laboratory. It uses a PC/104 based control and data acquisition system, Inertial and Satellite based Navigation Systems, and a Wireless Local Area Network. For this system, an example of control architecture based on the object-oriented paradigm is presented.

Advances in micromilling techniques: a new apparatus for acquiring high-resolution oxygen and carbon stable isotope values and major/minor elemental ratios from accretionary carbonate

A computer-controlled micromilling apparatus that permits discrete sampling of accretionary biogenic carbonate specimens with micron-scale resolution has been developed for the purpose of acquiring high-resolution δ 13C and δ 18O values, and major/minor elemental chemistry. Secular variation in stable isotope ratios and major/minor elemental composition records inter-annual and intra-annual changes in the environmental parameters or animal behavior for extant and extinct species. A polished specimen is attached to a stage beneath a fixed micro-milling head, and viewed on a large-screen monitor via a color digital camera. Growth bands (analogous to tree rings) are generally a result of variable accretion rates in biogenic carbonates. These growth features are first digitized in real-time as a series of three-dimensional coordinates. To better characterize complex growth features, intermediate coordinates are interpolated using a cubic spline fit through the digital points. Intermediate sampling paths, which mimic less visible daily growth banding, are in turn calculated between digitized curves. Sampling path arrays serve to guide three high precision actuators, which position the sample stage relative to the fixed micromilling head. A fourth actuator provides vertical control of the digital color camera (compensating for vertical movement of the z-axis stage actuator) keeping the specimen image focused. This new micromilling device permits high-resolution sampling of complex internal structures via a user-friendly program interface.

Design and control of a mobile micromanipulator driven by ultrasonic motors with multidegrees of freedom

A miniature mobile micromanipulator system for performing submillimeter grasping and manipulation tasks has been designed and tested. The system consists of a two-fingered gripper attached to a 5 d.o.f. robot micromanipulator. Features of the system include: (i) the structure of the mobile micromanipulator is composed of high-precision ultrasonic actuators with several degrees of freedom (d.o.f.) (this makes the robot system easy to integrate and allows it to perform directed and precise translation motion or rotation in a plane or in space); (ii) the electronic drivers, based on a bidimensional PWM control architecture, allows us to command the multidirectional manipulator movement accurately, and, through them, to control the position and orientation of the gripper; and (iii) the gripper is actuated by a shape memory alloy actuator and employs strain gage sensors to perform the gripping force control. The prototype version of this mobile micromanipulator can perform micrometer movements with speeds in the range of few mm/s to several 10-1 m/s and manipulates objects in the size range of 2-0.5 mm. The design of the micromanipulator affords plenty of scope for further miniaturization. With the recent increased interest that has been shown in micro-robotics, the prototype robot system described in this paper could, with further development and miniaturization, form part of a micro-robot assembly system.

LINEAR GUIDE UNIT DRIVEN BY RODLESS CYLINDERER

This report describes the main features of a high precision actuator that is now required for assembling or testinghigh-tech products. The production equipments are highly sophisticated and there are more demands for accurate andcompact actuating units. Along with the demands, linear ball bearing guides are widely used in coupling with air cylindertype actuators. We introduce here the new concept linear guide unit driven by compact magnetically coupled aircylinder, which offers full specifications of the guide in the utmost compactness.

Silicon-micromachined micromirrors with integrated high-precision actuators for external-cavity semiconductor lasers

We present an actuated silicon-micromachined micromirror with continuous and highly accurate position adjustment designed to be used in the construction of external-cavity semiconductor-laser modules. In our initial design, a positioning accuracy better than /spl plusmn/0.2 μm for the actuated micromirrors is obtained. The mechanical robustness, small size, and fine-positional precision of the actuated micromirrors are sufficient for external-cavity-laser applications. In production, the cost of these miniature external-cavity-laser systems should be low because they are batch-processed.