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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A Large Force Haptic Interface with Modular Linear Actuators
This paper presents a haptic interface with modular linear actuators that addresses the limitations of conventional devices based on rotary joints. The proposed haptic interface is composed of parallel linear actuators that provide high backdrivability and small inertia. The performance of the haptic interface is compared to those of conventional mechanisms in terms of force capability, reflected inertia, and structural stiffness. High stiffness, large range of motion, and high force capability, which are in trade-off relationships in traditional haptic interfaces, are achieved. The device can apply up to 83 N continuously, i.e., three-fold more than most haptic devices. The theoretical minimum haptic force density and stiffness of the proposed mechanism are 1.3 to 1.9 and 37 times those of the conventional mechanisms under similar conditions, respectively. The system is scalable because the structural stiffness depends on only the timing belt stiffness, whereas that of conventional haptic interfaces is inversely proportional to the cube of the structural length. The modular actuator enables changes in the degrees of freedom (DOFs) for different applications. The proposed haptic interface was tested through an interaction experiment in a virtual environment with virtual walls.
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- Award ID(s):
- 2024775
- PAR ID:
- 10563168
- Publisher / Repository:
- MDPI
- Date Published:
- Journal Name:
- Actuators
- Volume:
- 12
- Issue:
- 7
- ISSN:
- 2076-0825
- Page Range / eLocation ID:
- 293
- 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
- Journal Article:
- https://doi.org/10.3390/act12070293
