Design of haptic systems that guarantee stable interaction is a challenging task. Virtual environments are typically highly nonlinear—resulting in a nonpassive discrete-time model. This paper will investigate how nonlinear mass/spring/damper virtual environments can be designed to guarantee the absence of oscillations and other chaotic behavior in the signal presented to the human operator. In ...

although there are many potential benefits associated with the use of virtual product development teams, exploiting these benefits requires an appropriate management. managing virtual product development team is a critical issue as many of these teams fail to accomplish their goals. review of previous literature shows that body of knowledge in managing virtual product development teams is fragm...

To obtain new ways of detecting weak signals, we analyzed the motion of a Duffing oscillator in different input states by solving the Duffing equation and then elaborating on the basic principles of weak signal detection based on Duffing oscillator phase-change characteristics. The experiment that shows how to achieve weak signal detection with a Duffing oscillator based on virtual instrument t...

AbstmctIn this paper, a sliding mode control scheme that guarantees the smoothness of the control signal and the exponential error convergence is proposed for robot manipulators. The proposed method inserts a low pass filter (LPF) in front of the plant, and the vzrtval controller is designed for the vzrtval plant the combination of the LPF and the robot manipulator. The virtual control signal c...

We propose a signal representation for transmit-receive uniform linear arrays operating over arbitrary time-varying spatial multipath channels encountered in mobile communications. The signal representation decomposes the multipath channel into a nite number of virtual channels that correspond to certain delays, Doppler shifts, angles that are xed a priori and are independent of the physical ch...

The work presented in this paper is aimed at the implementation of a real-time multiple-input multiple-output (MIMO) imaging radar used for area surveillance. In this radar, the equivalent virtual array method and time-division technique are applied to make 16 virtual elements synthesized from the MIMO antenna array. The chirp signal generater is based on a combination of direct digital synthes...

The mouse cerebral cortex was imaged in situ by photoacoustic tomography (PAT). Instead of a flat ultrasonic transducer, a virtual point detector based on a high numerical aperture (NA), positively focused transducer was used. This virtual point detector has a wide omnidirectional acceptance angle, a high sensitivity, and a negligible aperture effect. In addition, the virtual point detector can...