Slave Operation Research Articles

Design of imbalance compensator to mitigate circulating currents under master–slave operation of inverters

Design of imbalance compensator to mitigate circulating currents under master–slave operation of inverters

Accurate Parameter Estimation for Master–Slave Operation of a Surgical Robot

In this paper, a parameter estimation method is proposed to predict the simultaneous joint dynamics of a surgical robotic arm that is tracking trajectories. It mainly deals with the design, modeling, prototyping and control of a serial robotic arm for robot-assisted urological surgery. This robot is composed of many joints mounted in series with the surgical tool end performing both a translational workspace and a cone-shaped orientation workspace. The joints dynamics is obtained by trajectory planning of the tool end in the virtual prototype modeling environment. The motor drive system is parameterized for design, and its comprehensive performance in motion is predicted accurately. The heterogeneous master–slave control system was built, and the performances of the master–slave prototype were experimentally evaluated by measuring the positioning error of the virtual fixed point and the surgical tool end along the planned trajectory.

Development of a Portable Input Device for Master Slave Operation used for Disaster Response Robots based on Systems Engineering

Development of a Portable Input Device for Master Slave Operation used for Disaster Response Robots based on Systems Engineering

Task analysis of human-in-the-loop tele-operated maintenance: What can be learned from JET?

Remote maintenance will determine the available uptime of future fusion plants such as ITER. Experience at predecessor JET showed that a human-in-the-loop tele-operated approach is crucial, although this approach entails drawbacks such as the unavoidable extensive operator training and relatively long execution times. These drawbacks are common knowledge, but little quantitative research is available to guide improvements (such as improved training methods, or active operator support systems). The aim of this paper is to identify the key areas for further improvement of tele-operated maintenance. This is achieved by a detailed task analysis based on recent maintenance at JET, using task logbooks and video data as well as interviews with experienced master–slave operators. The resulting task analysis shows the (sub)tasks that were most time-consuming and shows a large variance in time performance within operators, but also substantial differences between qualified operators with different levels of experience. The operator interviews indicate that intuitive (virtual) visual feedback and artificial (guiding) forces are promising directions for improvement. The results found in this study will be used for future research and development activities focusing on haptic guiding strategies, with the aim to further design and optimize RH maintenance systems for ITER and beyond.

Direct manipulation of tool-like masters for controlling a master-slave surgical robotic system

Robotic-assisted minimally invasive surgery (MIS) can benefit both patients and surgeons. However, the learning curve for robotically assisted procedures can be long and the total system costs are high. Therefore, there is considerable interest in new methods and lower cost controllers for a surgical robotic system. In this study, a knife-master and a forceps-master, shaped similarly to a surgical knife and forceps, were developed as input devices for control of a master-slave surgical robotic system. In addition, a safety strategy was developed to eliminate the master-slave orientation difference and stabilize the surgical system. Master-slave tracking experiments and a ring-and-bar experiment showed that the safety tracking strategy could ensure that the robot system moved stably without any tremor in the tracking motion. Subjects could manipulate the surgical tool to achieve the master-slave operation with less training compared to a mechanical master. Direct manipulation of the small, light and low-cost surgical tools to control a robotic system is a possible operating mode. Surgeons can operate the robotic system in their own familiar way, without long training. The main potential safety issues can be solved by the proposed safety control strategy.

An asynchronous high-speed synchrotron shutter

A high-repetition-rate mechanical shutter with asynchronous control and sub-millisecond operation has been developed and tested for specialist X-ray systems in the field of medical diagnostics and radiation therapy. Capacitor-coupled linear voice coil actuators are utilized to achieve opening and closing speeds as fast as 700 micros for an aperture height of 4 mm. The design allows for asynchronous control, permitting slave operation of the shutter, a feature that is distinctly suitable for a number of applications including particle image velocimetry, where high-frame-rate operation must be accurately synchronized and triggered by the image acquisition sequence of the detector or timing device. The design and construction of the shutter also makes it ideal, with simple and limited modifications, for applications requiring larger apertures, in particular wide beams as found in many synchrotron beamlines.

Image Information Based Configuration Control of Redundant Manipulator in Bilateral System

The paper proposes a construction method of bilateral system using redundant manipulator. In bilateral system, it is important that operation can be realized in narrow space and at remote plate. Then the master-slave robots with redundancy are convenient and needed to achieve the bilateral motion effectively. However, human operation will become difficult because of the multifunctional mechanism. Especially, operating the posture of redundant manipulator by human hand is so difficult because the manipulator redundancy enables to achieve infinite number of the manipulator posture. This paper focuses on a construction of bilateral system so that it assists the human operation by adjusting a configuration control of redundant manipulator. In particular, bilateral system utilizes visual information by cameras to recognize the target object of remote environment in slave. By using this camera information, the assist for the slave operation of redundant manipulator is realized without deteriorating the bilateral motion.

Sliding Mode Control

Sliding Mode Control

Particle-flux separation of electrons in the half-filled Landau level: Chargeon-fluxon approach

We have previously studied the phase structure at finite temperatures of the Chern-Simons (CS) gauge theory coupled with fermions by using lattice gauge theory. In this paper, we formulate the “chargeon-fluxon” representation of electrons and use it to reinvestigate the phenomenon of particle-flux separation (PFS) of electrons in the half-filled Landau level. We start with a lattice system of fermions interacting with a CS gauge field, and introduce two slave operators named chargeon and fluxon that carry the CS charge and flux, respectively. The original fermion, the composite fermion of Jain, is a composite of a chargeon and a fluxon. We further rewrite the model by introducing an auxiliary link field, the phase of which behaves as a gauge field gluing chargeons and fluxons. Then we study a confinement-deconfinement transition of that gauge field by using the theory of separation phenomena as in the previous paper. The residual four-Fermi interactions play an important role to determine the critical temperature T PFS, below which the PFS takes place. The new representation has some advantages; (1) It allows a field-theoretical description also for the flux degrees of freedom. (2) It has a close resemblance to the slave-boson or slave-fermion representations of the t- J model of high- T c superconductors in which an electron is a composite of a holon and a spinon. This point opens a way to understand the two typical separation phenomena in strongly correlated electron systems in a general and common setting.

An intermittent frequency offset lock of a transverse Zeeman laser to an iodine stabilized He-Ne laser

A single-mode frequency stabilized laser with modulation-free and moderate power is desired as a light source for an ultra-high resolution interferometer system and/or a rapid laser calibration system. For this purpose, we developed a new stabilized laser system that utilizes intermittent control of a 2 mW transverse Zeeman stabilized He-Ne laser (Zeeman laser) with an iodine stabilized He-Ne laser (I2 stabilized laser). Because of the intermittent control, working time of the I2 stabilized laser is reduced. The Zeeman laser has two operational modes: independent and slave mode. In the independent mode, the Zeeman laser is stabilized through control of Zeeman beat frequency. Temperature dependent drift of the oscillation frequency during the independent mode is periodically corrected by the slave operation utilizing frequency offset locking to the I2 stabilized laser. Frequency instability of the Zeeman laser in independent and slave modes is 7.7X10-11 and 2.0X10-11, respectively, at the sampling time of 100 s.

A field-theory approach to the t- j model and the spin-charge separation

We analyze the t- J model using the C P 1 representation for the slave operators (holons and sp spinons) which is particularly suited to study the phenomenon of the spin-charge separation in strongly correlated electron systems. In particular, we show that for the one-dimensional t- J model below half-filling the low-energy effective dynamics of the spin and charge degrees of freedom is represented in the continuum limit by a C P 1 model with a topological term, minimally coupled to a massless Dirac field with a four-fermion interaction. The bosonic term of this action describes the spin waves produced by the spinons, while the fermionic term represents the low-energy charge excitations. This theory exhibits explicitly a local abelian gauge invariance.

Slave anyons in the t- J model at the supersymmetric point

We discuss the properties of the supersymmetric t- J model in the formalism of the slave operators. In particular we introduce a generalized abelian bosonization for the model in two dimensions, and show that holons and spinons can be anyons of arbitrary complementary statistics (slave-anyon representation). The braiding properties of these anyonic operators are thoroughly analyzed, and are used to provide an explicit linear realization of the superalgebra SU(1|2). Finally, we prove that the hamiltonian of the t- J model in the slave-anyon representation is invariant under SU(1|2) for J = 2 t.

Design of a FASTBUS Programmable Sequencer Module and Memory Module

A programmable sequencer and a memory module have been designed and built to demonstrate high speed operation of the FASTBUS, and to study design implications of the FASTBUS specification. Both are implemented in ECL, and illustrate master and slave operation, arbitration circuit design, and logical and geographical addressing considerations.

Global Navigation Display

this paper deals with the development of a display technique utilizing a point source lamp for projection through an optical quality globe to create a continuous cartographical display. The globe contains cartographic information on a one to two million scale. The display is capable of scale factor changes without loss of detail or the use of optical systems to retain the focus. The globe is gimballed on four axes to provide the capability of either command or slave operation of the display when it is used in conjunction with an automatic navigational computer. Servo accuracies which are capable of maintaining positional display within one tenth of a minute of latitude and longitude are used for the various drive loops. Slave operation is also maintained for either heading or track reference and thereby permits the orientation of the display to be maintained under all operating conditions.