A modified AHP algorithm for network selection

This paper addresses the concept of ranking networks to the multiple criteria of customers to find the best and alternative networks. The use of modified AHP algorithm has been shown to provide better network ranking for reasonable customer objectives than the traditional AHP method. Both the traditional method and the proposed method produced results subjective to the customer requirements. However, the proposed method is more intuitive to the customers through direct capture of their exact requirements rather than an interpretation of their requirements through pair-wise comparison alone. Also, the proposed method is less time-consuming and results are of higher quality

Free singularity path planning of hybrid parallel robot

This paper presents a singularity-free path planning approach for a hybrid parallel robot. The hybrid robot is composed of two well-known parallel robots, a hexapod and a tripod, that are serially connected. In this paper a methodology is developed to avoid singularity configurations of the hybrid parallel robot. Nominal polynomial paths are used for motion of end effector, and the strokes of each actuator is calculated by using the developed inverse kinematic. A MATLAB program has been developed to generate the designed paths, and several poses have been tested in a CAD model of the hybrid parallel robot to validate the feasibility of the path planning approach

Design and analysis of a 9 DOF : hybrid parallel robot

The research presented in this thesis discusses the design of a new configuration of a hybrid parallel robot with nine degrees of freedom. Parallel robots have been studied due to their high stiffness and accuracy rather than serial robots. However, parallel mechanisms have not been widely used in industry due to the lack of workspace. A major advantage of the proposed hybrid parallel robot is to increase the work volume while the stiffness of the system remains suitable for a range of industrial applications. Novel dynamic formulations have been developed by using Newton Euler and inverse kinematics in order to identify the best configurations based on stiffness and velocity of system in any particular position. The developed program determines the velocity and stiffness of the system for each configuration. A physical robot prototype built to test the developed theoretical model. The control strategies of the robot were developed and tested based on both point to point control and continuous path applications. The path between two points was selected based on the stiffness of the system in a particular position and orientation. A robotic ankle rehabilitation application was successfully used to verify the design of the proposed hybrid parallel robot

Path-planning of a hybrid parallel robot using stiffness and workspace for foot rehabilitation

Stiffness is one of the important parameters for estimating the performance of hybrid parallel robots as it is not constant throughout its workspace. The aim of this study is to provide an optimum path based on maximum stiffness within the workspace of a 9-degree-of-freedom hybrid parallel mechanism configuration, which includes nine linear actuators connecting one stationary and two moving platforms in series. The proposed robot is designed for ankle rehabilitation, where accurate and precise movement of lower extremities is required. The design takes advantage of two important characteristics of parallel robots: stiffness and workspace. The proposed methodology to determine the stiffness of hybrid robot in three single axes is based on calculation of position vector of each actuator in any particular pose, by considering the inverse kinematics of the system, in order to obtain the magnitude and direction of the applied forces. The results obtained from the workspace calculations have been compared with those of two standard parallel mechanisms including a 6-degree-of-freedom hexapod and a tripod with 3 degrees of freedom. The stiffness of the robot has been calculated in simulation and then compared with those of a developed prototype hybrid model in two different case studies