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Haptic perception and display of softness are important parts of the haptic display technique, which is currently the frontier in teleoperation systems and human-computer interaction. A portable softness display device is developed for this study. The device can quickly change the displayed stiffness by controlling the deformable length of the elastic element. Ideally, when a human operator's fingertip...
This work presents a stability analysis for an architecture for teleoperating a laboratory crane using haptic devices. The teleoperation scheme chosen is the 2-channel force-force (FF) architecture. This scheme is modeled first by state-space equations testing that the system is Hurwitz stable for zero delay and verifying the Schur-Cohn stability of the matrix C, a necessary and sufficient stability...
This paper presents an LMI approach to design a robust controller for teleoperation systems with unsymmetric time-varying delays. The position error feedback control scheme is considered for the master and slave manipulators. The overall systems is modelled as differential equations with multiple time delays. By using Lyapunov functional, we give the sufficient stability condition dependent on the...
The problem of communication delay in bilateral or teleoperation systems is even more emphasized with the use of the Internet for communication, which may give rise to loss of transparency and even instability. To address the problem, numerous methods have been proposed. This study is among the few recent studies taking a disturbance observer approach to the problem of time delay, and introduces a...
Teleoperation systems have been used in various situations such as space tasks, rescue activities, military missions, undersea operations and unmanned constructions. Compared to direct operation, teleoperation performance is limited by a lack of awareness of remote location environments. In this paper, tactile feedback on construction machine teleoperation performance is discussed. We measured the...
This paper reports on studies we are conducting to evaluate 3D stereoscopic rendering systems accuracy and efficiency. These studies are part of our project dealing with tele-operation, namely the use of virtual reality technology to increase immersion feeling of teleoperators and to test specific conditions by changing the feeled physical laws. We concentrate on depth perception because it has been...
In general, the hydraulic excavator is used on many construction sites, but in many cases, these construction sites are bad environmental conditions. Therefore, the unmanned excavator system is required. In recent years, the teleoperation systems have been developed and some of them are in practical use. In these systems, the operator cannot sense condition of site directly, so the work efficiency...
Researchers have studied teleoperation systems essentially for implementation in critical tasks. Although teleoperation systems require stability apriori, time delays over the communications lines become a major source of instability. During the last two decades several researchers have focused on the time delay problem. The wave variable technique is one of the teleoperation controllers developed...
In this work we study the stability of several standard teleoperation schemes. This problem is usually addressed by frequency domain Laplace techniques or by passivity techniques. We use an LMI approach based on Lyapunov-Krasovskii functionals. Firstly, the schemes are modelled as differential-delayed equations which are of the neutral type, that is, the delay affects not only the state but also the...
ER fluids are functional fluids which have attracted attention in recent years. We have developed a new type of actuator using ER fluid. This ER actuator responds quickly, and has large torque/inertia ratio. ER actuators are thus suited to be the actuators used in force feedback systems. We have developed a force feedback system using ER actuators, and have enacted some basic experiments for force...
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