Control of Position and Grasping Force With Cooperating Arms: A Feedback Linearization Approach

ABSTRACT Robotic applications require coordination of multiple manipulators. This paper discusses an approach for control of manipulators with given end-effector stiffness properties. The approach is designed for concurrent regulation of position of a work piece and grasping force applied by the manipulators on the work piece. The approach is based on input-output feedback linearization. Simulations demonstrate feasibility of the proposed control scheme

An Efficient Wireless Extension Point Placement Algorithm in Urban Rectilineal WLANs

Abstract — With a small amount of software modification, wireless Extension Points (EPs), which are now commercially available, can be used to improve the throughput capacity of a Wireless Local Area Network (WLAN). An EP is an immobile device that has access to the power supply or is equipped with a high capacity battery but does not have direct access to the Internet. They relay data wirelessly between the Access Point (AP) and the mobile hosts. In this paper, we investigate the optimal placement of EPs such that the throughput capacity of an urban rectilineal WLAN can be maximized. Two channel models are studied, based on the Shannon capacity bound and IEEE 802.11 specifications. We first formulate a solution for the optimal EP placement problem in a general network scenario as a non-linear programming problem, then we propose an efficient algorithm that determines the optimal locations of a fixed number of EPs in a rectilineal network. Our results show that, for a wide range of system parameters, the optimally placed EPs can significantly increase the network throughput capacity. Moreover, we study how the number of EPs, transmission power, path loss exponent, channel models and traffic characteristics affect the optimal EP placement and expected throughput capacity of the network. Index Terms — wireless local area networks, access point, extension point, optimal placement, capacity improvement, mathematical programming/optimization. I