F. Infed, S. Brown, C. Lee, D. Lawrence, A. Dougherty, and L. Pao, "Combined Visual/Haptic Rendering Modes for Scientific Visualization", Proc. 1999 ASME International Congress and Exposition, Symposium on Haptic Interfaces for Teleoperation and Virtual Reality, DSC-Vol. 67, Nashville, TN, November 1999, pp. 93--99.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....much less certain of the force rates required in vector or flow field visualization. Flow fields typically change gradually, but they may change suddenly in turbulent regions. We may also wish to restrict haptic interfaces to an isosurface, which then acts like a hard wall as above. Infed et al. [12] constrain a stylus to lie along streamlines. Therefore it is likely that high computational rates are required for scientific visualization also. 5 Locomotion Interfaces Locomotion interfaces are energy extractive devices that, in a confined space, simulate unrestrained human mobility such as ....

Infed, F., Brown, S.W., Lee, C.D., Lawrence, L.A., Dougherty, A.M., and Pao. L.Y., "Combined Visual /Haptic Rendering Modes for Scientific Visualization, " Proc. ASME Dynamics Systems and Control Division, Nashville, 1999, in press.

....sets on the order of 1 million elements by real time haptic rendering can be accomplished. INTRODUCTION In scientific visualization applications of haptic interfaces, forces are applied to the user s hand which depend on values of data associated with physical locations in a data field. See e.g. [1]. As the user moves their hand, a corresponding virtual position in the data field changes. Data at that new position is then converted into (possibly different) forces to help the user understand the meaning of the data via changes in the feel generated by applied forces. For example, a vector ....

.... r) 8 N 3 = 1 p) 1 q) 1 r) 8 (1) N 4 = 1 Gamma p) 1 Gamma q) 1 r) 8 N 5 = 1 Gamma p) 1 Gamma q) 1 Gamma r) 8 N 6 = 1 p) 1 Gamma q) 1 Gamma r) 8 N 7 = 1 p) 1 Gamma q) 1 r) 8 Note that these functions are a partition of unity for any val p q r 1 0 3 7 5 6 2 4 p [ 1,1] r [ 1,1] q [ 1,1] x z y 0 3 1 2 4 7 5 6 P(p,q,r) Figure 1. Cube shaped element in Cartesian and parametric (nondimensional) coordinate spaces. ues of (p;q;r) since they sum to 1. Each shape function N i , provides a measure of the proximity of the point P to its ....

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F. Infed, S. Brown, C. Lee, D. Lawrence, A. Dougherty, and L. Pao, "Combined Visual/Haptic Rendering Modes for Scientific Visualization", Proc. 1999 ASME International Congress and Exposition, Symposium on Haptic Interfaces for Teleoperation and Virtual Reality, DSC-Vol. 67, Nashville, TN, November 1999, pp. 93--99.

....orientation, and mechanical properties such as viscosity and stiffness. We have previously developed visual haptic modes for scientific visualization to show that the use of haptics can help the user to more easily understand cluttered graphical displays of streamlines in an electromagnetic field [5]. In this, the appropriate combination of haptic and visual rendering can help the user to simultaneously focus on local behavior (e.g. a single streamline) while retaining a global orientation from a field of many other streamlines. However, care must be taken in designing combined haptic visual ....

....behavior (e.g. a single streamline) while retaining a global orientation from a field of many other streamlines. However, care must be taken in designing combined haptic visual modes; if done inappropriately, the resulting combined display can be more confusing than the graphics display alone [5]. Augmenting graphical visualization with a multiple DOF haptic interface also extends data display to allow direct manipulation of the data. A 5 DOF haptic interface, such as that shown in Figure 1, replaces the 2 DOF mouse and enables the user to grab onto the data set and manipulate it for ....

F. Infed, S. W. Brown, C. D. Lee, D. A. Lawrence, A. M. Dougherty, and L. Y. Pao. "Combined Visual/Haptic Rendering Modes for Scientific Visualization", Proc. ASME Int. Mech. Eng. Congress, Dynamic Systems and Control Div., DSC-Vol. 67, Nashville, TN, pp. 93--99, Nov. 1999.

....is limited by a variety of factors. Closed loop bandwidth is limited by the complexity of calculations within the control loop. We designed the controller for use with one of our 5 rod data visualization applications, which we call the orientation constraint (OC) haptic rendering mode (see [19]. Table 1 lists the calculation times for the various tasks this mode entails. For this application, the control loop rate is 2207 Hz. Based on the common 1 10 rule of thumb, we hope for a closed loop bandwidth of 220 Hz, which is unfortunately lower than the 300 Hz bandwidth indicated in Section ....

....the controller block to cancel out these coupling effects. Thus far, the performance for the multivariable setup is not as good as that detailed here for a single rod. Initial use of this overall control system for the interface has shown good performance in scientific visualization applications [19]. On going and future work includes (1) more carefully assessing the coupling between the rods and designing a controller for the interface from a direct multivariable control framework and (2) developing models of the nonlinearities (such as friction) for use in the controller design. ....

F. Infed, S. W. Brown, C. D. Lee, D. A. Lawrence, A. M. Dougherty, and L. Y. Pao. "Combined Visual /Haptic Rendering Modes for Scientific Visualization ", Proc. ASME Int. Mech. Eng. Congress and Exposition, Dynamic Systems and Control Div., DSC-Vol. 67, Nashville, TN, pp. 93--99, Nov. 1999.

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