Improved transparency in energy-based bilateral telemanipulation

In bilateral telemanipulation algorithms based on enforcing time-domain passivity, internal friction in the devices poses an additional energy drain. This can severely decrease the obtainable transparency of these algorithms when high amounts of friction are present in the slave device. Based on a model of the friction, the dissipated energy can be estimated and reclaimed inside the energy balance of the control algorithm. Extending the energy balance which is monitored, decreases the net passivity of the telemanipulation system enforced by the control algorithm, which usually enforces passivity of just the bilateral controller. Experimental results are provided that demonstrate the effectiveness of the proposed approach in increasing the obtainable transparency. As long as the physically dissipated energy is underestimated, the telemanipulation system as a whole will remain passive. Thus the guaranteed stability property of the time-domain passivity algorithm is maintained. 2011 Elsevier Ltd. All rights reserved.