IEEE/ASME Transactions on Mechatronics

This note clarifies the design of proportional derivative (PD) controllers for the magnetic levitation systems of micro permanent magnet (PM) motors proposed in the original paper of Komori and Yamane (ibid., vol.6, p.43-9, 2001). It is shown that the PD controllers cannot stabilize the described levitated micro motors because it is necessary to use other values of parameters for these controllers... View full abstract»

A general framework for ultra precision motion control of magnetic suspension actuation systems with large travel ranges in multiple degrees of freedom (DOF) is presented. It encompasses the development of nonlinear electromagnetic force model for 6-DOF actuation, and the design of the necessary control architecture for ultra precision motion control of magnetic suspension actuation systems. A 6-D... View full abstract»

To cope with the severe specification such as a concurrent realization of high accuracy and wide operating range demanded in many fields, we suggest a contact-free planar system that realizes the spatial motion of a plate by generating a levitation force and a thrust force at the same plane concurrently. The system utilizes an interaction between the direct drive DC coils of a common shape and the... View full abstract»

Piezoelectric transducer (PZT) patches can be attached to a structure in order to reduce vibration. The PZT patches essentially convert vibrational mechanical energy into electrical energy. The electrical energy can be dissipated via an electrical impedance. Currently, impedance designs require experimental tuning of resistive circuit elements to provide optimal performance. A systematic method is... View full abstract»

Theoretical predictions were made for the dynamic performance of a tangential flux magnetic thrust bearing. A prototype bearing was built with the stators and rotors made from tape wound strip. The performance of this bearing was measured and compared to the theoretical predictions and also to the performance of a radial flux thrust bearing. Tangential flux bearings are intrinsically amenable to c... View full abstract»

This paper describes an approach to nonmodel-based decentralized controls of multirobot systems utilizing structural flexibility in gripper design to avoid large unwanted internal forces acting on multirobot systems. It is proven in theory that a simple proportional and derivative (PD) position feedback plus gravity compensation controller can regulate the desired position/orientation of a payload... View full abstract»

Swing up and balance control are two interesting control problems for the Pendubot. Many studies have been conducted for swing up control of the Pendubot. A few results have been reported for feedback stabilization of the Pendubot. In this paper, we apply a new hybrid controller for feedback stabilization of the Pendubot. It is well-known that it is impossible to use smooth feedback to stabilize a... View full abstract»

In biaxial motion systems, applying the cross-coupled control (CCC) significantly improves contouring accuracy for linear and circular contours. As geometrical and parametric curves become more popular in modern manufacturing, machining processes with multiaxis motion systems are required, however, the available biaxial CCC cannot be directly applied to arbitrary contours with multiaxis machining ... View full abstract»

Presents a prototype microrobot based on magnetic principles. Miniature items are to be transported and assembled in hazardous environments. A microrobot can be remotely operated with 3 DOF in an enclosed environment by transferring magnetic energy and optical signals from outside. The magnetic drive unit consists of 8 electromagnets (4 pairs), 2 permanent magnets, a return yoke and a pole piece. ... View full abstract»

A number of researchers have been investigating the use of Stewart platforms (or hexapods) for precision applications including machining, vibration isolation and precise pointing. To avoid friction and backlash, these hexapods often employ flexure joints. This does eliminate nonlinear friction and backlash, but adds linear spring/damper dynamics. In addition, since the motion is so accurate, base... View full abstract»

The use of embedded personal computing (PC) technology allows desktop computer applications to evolve into the real-time control world. Such systems will be compact, reliable and low in cost. However, the mainstream PC platforms such as Windows NT have shortcomings concerning their real-time capabilities. The integration of embedded PC and Internet technologies make distributed real-time control a... View full abstract»

A disk-type integrated motor-bearing system having axial magnetic flux is newly invented and its design, analysis, and control methods are presented. Sinusoidal motoring currents to four symmetrically placed winding groups produce a torque, whereas control currents of the same magnitude but opposite signs added to the opposite winding groups create radial forces. The control currents are intended ... View full abstract»