Handheld haptic devices are often limited in rendering capability, as compared to traditional grounded devices. Strenuous design criteria on weight, size, power consumption, and the ungrounded nature of handheld devices, can drive designers to prioritize actuator force or torque production over other components of dynamic range like bandwidth, transparency, and the range of stable impedances. Hybrid actuation, the use of passive and active actuators together, has the potential to increase the dynamic range of handheld haptic devices due to the large passive torque capability, the stabilizing effects of passive actuators, the high bandwidth of conventional DC servomotors, and the synergy between actuators. However, to date the use of hybrid actuation has been limited due to the highly nonlinear torque characteristics of available passive actuators that result in poor rendering accuracy. This paper describes a hybrid actuation approach and novel control topology which aims to solve actuation challenges associated with nonlinear passive actuators in hybrid and handheld haptic devices. The performance of the device is assessed experimentally, and the approach is compared to existing handheld devices.
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Stability and Rendering Limitations of a Parallel Hybrid Active-Passive Haptic Interface
Impedance based kinesthetic haptic devices have been a focus of study for many years. Factors such as delay and the dynamics of the device itself affect the stable rendering range of traditional active kinesthetic devices. A parallel hybrid actuation approach, which combines active energy supplying actuators and passive energy absorbing actuators into a single actuator, has recently been experimentally shown to increase the range of stable virtual stiffness a haptic device can achieve when compared to the active component of the actuator alone. This work presents both a stability and rendering range analysis that aims to identify the mechanisms and limitations by which parallel hybrid actuation increases the stable rendering range of virtual stiffness. Increases in actuator stability are analytically and experimentally shown to be linked to the stiffness of the passive actuator.
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- Award ID(s):
- 1830516
- NSF-PAR ID:
- 10353040
- Date Published:
- Journal Name:
- IEEE Haptics Symposium 2022 (HAPTICS)
- Page Range / eLocation ID:
- 1 to 8
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/HAPTICS52432.2022.9765621
