Stability and transparency improvement in haptic device employing both MR-brake and active actuator

Date

2012-12-14

Author

Baser, Ozgur
Konukseven, Erhan İlhan
Gurocak, Hakan

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This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

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An ideal haptic device should transmit a wide range of stable virtual model impedances (Z-width) with high transparency. Magneto-rheological fluid (MR) brakes are advantageous in haptic devices since they are passive actuators. However, they cannot provide high transparency and smooth interaction due to high viscous friction, residual torque, slow response, sticking and hysteresis effects. On the other hand, active actuators cannot simulate high virtual impedances stably, but provide high transparency with a closed loop control algorithm. In the proposed hybrid actuation a task divider control (TDC) algorithm was developed for torque sharing between two actuators to provide a large Z-width and improve both transparency and smoothness. The algorithm employs two parameters which were estimated experimentally and extended to entire achievable impedance range by artificial neural network (ANN) and curve fitting techniques. A 1-DOF device having an excitation motor at the user side and brushless DC motor and MR-brake in the haptic side was used in the experiments. The excitation motor is used to generate a white noise torque input to simulate a user for frequency domain transparency tests. Results of the proposed and conventional closed loop impedance control (CLIC) algorithms were compared. The proposed algorithm improves the transparency of MR-brake by eliminating its drawbacks and presents a larger Z-width than the active actuator alone.

Subject Keywords

Actuators, Torque, Haptic interfaces, Impedance, Stability analysis, Artificial neural networks, Friction

URI

https://hdl.handle.net/11511/38491

DOI

https://doi.org/10.1109/roman.2012.6343724

Collections

Department of Mechanical Engineering, Conference / Seminar

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Citation Formats

O. Baser, E. İ. Konukseven, and H. Gurocak, “Stability and transparency improvement in haptic device employing both MR-brake and active actuator,” 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/38491.