Haptic Display With an Interface Device Capable of Continuous-Time Impedance Display Within a Sampling Period

Kawai, Masayuki; Yoshikawa, Tsuneo

doi:10.1109/tmech.2004.823877

Cited by 26 publications

(8 citation statements)

References 10 publications

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“…Also related is the work of Kawai and Yoshikawa, in which the authors implement an analog circuit to control the stiffness and damping of each joint in a multi-degree of freedom haptic display [8], [9]. The result is similar to the effect of a virtual coupling in that the stiffness and damping values are limited to ensure that the resulting behavior of the haptic display is stable while interacting with objects both in the virtual environment and in the real world.…”

Section: Active Electrical Dampingmentioning

confidence: 99%

Measuring and Increasing Z-Width with Active Electrical Damping

Weir

Colgate

Peshkin

2008

2008 Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems

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The "Z-Width" of a haptic display is the dynamic range of impedances that can be passively rendered. Haptic displays with larger Z-width generally render more realistic feeling virtual environments.We present a new method for measuring and displaying the Zwidth of a haptic display. Instead of stiffness-damping plots, we believe a more illustrative technique for plotting the Z-width of a haptic interface is the envelope of achievable passive impedances as a function of frequency. Both hardware and analysis software for this new type of Z-width measurement are discussed.As previous research has shown, the maximum passive impedance that a device can render is directly related to the physical damping available in the mechanism. In an effort to maximize the Z-width of the haptic display, we present a new technique for adding physical damping to a haptic display through the use of analog electronics in the motor amplifier. Due to its electrical nature, active electrical damping has the benefit of dynamically variable parameters with no added mechanical complexity or mass.With the addition of active electrical damping, we show a performance improvement via a larger Z-width and larger range of passive virtual environment parameters.

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Section: Active Electrical Dampingmentioning

confidence: 99%

Measuring and Increasing Z-Width with Active Electrical Damping

Weir

Colgate

Peshkin

2008

2008 Symposium on Haptic Interfaces for Virtual Environment and Teleoperator Systems

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“…Noise limits the performance of any analog control system. It is seen that all continuous time implementation attempted so far [10] and [11] involve analog circuitry. If we can eliminate the noise problems we might be able to develop a high performance analog control loop for haptic devices.…”

Section: Bmentioning

confidence: 99%

Rendering stiffer walls: a hybrid haptic system using continuous and discrete time feedback

2007

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Instability in conventional haptic rendering destroys the perception of rigid objects in virtual environments. Inherent limitations in the conventional haptic loop restrict the maximum stiffness that can be rendered. In this paper we present a method to render virtual walls that are much stiffer than those achieved by conventional techniques. By removing the conventional digital haptic loop and replacing it with a part-continuous and part-discrete time hybrid haptic loop, we were able to render stiffer walls. The control loop is implemented as a combinational logic circuit on an FPGA. We compared the performance of the conventional haptic loop and our hybrid haptic loop on the same haptic device and present mathematical analysis to show the limit of stability of our device. Our hybrid method removes the compute intensive haptic loop from the CPU, this can free a significant amount of resources that can be used for other purposes such as graphical rendering and physics modeling. It is our hope that in the future, similar designs will leads to a haptics processing unit or HPU.

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“…Coupling impedance must be calculated in a discrete-time system along with dynamic simulation of the virtual object and virtual environment. Therefore, stability is influenced by the sampling period [13]. The dynamic (a) Typical device with direct motor driving (b) Our device with elastics beam Fig.…”

Section: Eimentioning

confidence: 99%

“…The force exerted by the device is equal to the desired force in the virtual environment, that is (13) fa fv…”

Section: Eimentioning

confidence: 99%

Feeling the Softness of Virtual Objects with a Continuous and Passive Haptic Device

Song

2006

2006 10th International Conference on Computer Supported Cooperative Work in Design

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A new softness display system has been developed which is based on the principle of deformable length of elastic element control. (DLEEC) In this system, operator can feel the softness ofthe virtual objects with the softness display device. Compared with other haptic device, the device is passive and exert the react force only when the operator "actively touch" the virtual objects. The stability of the softness display system is analyzed, and some experimental results are presented to show the validity of the proposed approach.

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Haptic Display With an Interface Device Capable of Continuous-Time Impedance Display Within a Sampling Period

Cited by 26 publications

References 10 publications

Measuring and Increasing Z-Width with Active Electrical Damping

Measuring and Increasing Z-Width with Active Electrical Damping

Rendering stiffer walls: a hybrid haptic system using continuous and discrete time feedback

Feeling the Softness of Virtual Objects with a Continuous and Passive Haptic Device

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