Utilization of motor current based torque feedback to improve the transparency of haptic interfaces

In this paper motor current based torque feedback compensator is utilized in actuator space together with a closed loop impedance control algorithm instead of model based compensator to improve the transparency performance of haptic interfaces; moreover, a novel transparency evaluation metric is developed to evaluate the transparency performance of these devices. The proposed control algorithm is experimentally tested on a 1 DOF haptic device by employing a low-cost current sensor. It is also tested on a MATLAB/Simmechanics (R) model of a 2 DOF serial planar elbow type haptic manipulator to show that it is applicable to multi-DOF haptic systems. Free-motion, virtual-load and virtual-wall performance tests are conducted to compare the performance of the proposed control algorithm with the alternative algorithms by means of apparent inertial effects. The results show that the proposed algorithm significantly improves the transparency of the haptic devices.


Transparency improvement in haptic devices with a torque compensator using motor current
Baser, Ozgur; Konukseven, Erhan İlhan; Gurocak, Hakan (2012-12-01)
Transparency of a haptic interface can be improved by minimizing the effects of inertia and friction through the use of model based compensators. However, the performance with these algorithms is limited due to the estimation errors in the system model and in the velocity and acceleration from quantized encoder data. This paper contributes a new torque compensator based on motor current to improve transparency. The proposed method was tested experimentally in time and frequency domains by means of an excita...
Optimization of Power Conversion Efficiency in Threshold Self-Compensated UHF Rectifiers With Charge Conservation Principle
Gharehbaghi, Kaveh; KOÇER, FATİH; Külah, Haluk (2017-09-01)
This paper presents a compact model for threshold self-compensated rectifiers that can be used to optimize circuit parameters early in the design phase instead of time-consuming transient simulations. A design procedure is presented for finding the optimum aspect ratio of transistors used in the converter and number of rectifying stages to achieve the maximum power conversion efficiency. In the presented analysis, the relation between the power conversion efficiency and the load current over the variation o...
Stability and transparency improvement in haptic device employing both MR-brake and active actuator
Baser, Ozgur; Konukseven, Erhan İlhan; Gurocak, Hakan (2012-12-14)
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 ...
Hybrid control algorithm to improve both stable impedance range and transparency in haptic devices
Baser, Ozgur; Gurocak, Hakan; Konukseven, Erhan İlhan (2013-02-01)
An ideal haptic device should transmit a wide range of stable impedances with maximum transparency. When using active actuators, transparency improvement algorithms tend to decrease the range of attainable impedances. Passive actuators can transmit high impedances stably, but are not sufficient alone for transparency. In this study, a hybrid force control algorithm employing active and passive actuators was developed to improve the stable impedance range and transparency in haptic devices. A new transparenc...
A High Performance PWM Algorithm for Common Mode Voltage Reduction in Three-phase Voltage Source Inverters
Uen, Emre; Hava, Ahmet Masum (2008-06-19)
A high performance PWM algorithm with reduced common mode voltage (CMV) and satisfactory overall performance is proposed for three-phase PWM inverter drives. The algorithm combines the near state PWM (NSPWM) method which has superior overall performance characteristics at high modulation index and MAZSPWM, a modified form of the active zero state PWM method (AZSPWM1), which is suitable for low modulation index range of operation. Since AZSPWM1 has line-to-line voltage pulse reversals with small zero-voltage...
Citation Formats
O. Baser and E. İ. Konukseven, “Utilization of motor current based torque feedback to improve the transparency of haptic interfaces,” MECHANISM AND MACHINE THEORY, pp. 78–93, 2012, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/49039.