The harmonic index of a graph $G$, denoted by $H(G)$, is defined asthe sum of weights $2/[d(u)+d(v)]$ over all edges $uv$ of $G$, where$d(u)$ denotes the degree of a vertex $u$. Hu and Zhou [Y. Hu and X. Zhou, WSEAS Trans. Math. {bf 12} (2013) 716--726] proved that for any bicyclic graph $G$ of order $ngeq 4$, $H(G)le frac{n}{2}-frac{1}{15}$ and characterize all extremal bicyclic graphs.In this...

Quadruped robots have unique capabilities for motion over uneven natural environments. This article presents a stable gait for a quadruped robot in such motions and discusses the inverse-dynamics control scheme to follow the planned gait. First, an explicit dynamics model will be developed using a novel constraint elimination method for an 18-DOF quadruped robot. Thereafter, an inverse-dynamics...

in this paper, a new method was proposed for the navigation of a mobile robot in an unknown dynamic environment. the robot could detect only a limited radius of its surrounding with its sensors and it went on the shortest null space (sns) toward the goal. in the case of no obstacle, sns was a direct path from the robot to goal; however, in the presence of obstacles, sns was a space around the r...

The present study deals with a robot safety system composed of standby robot units and inbuilt safety unit. When the main operative unit fails, it is replaced by the standby robot unit available in the system. The concept of reboot delay is also incorporated in this study according to which the robot unit is rebooted if it is not successfully recovered. The recovery and reboot times of failed u...

Mobile mechanical manipulators are one of the automation aspects which were revealed in last years of twentieth century. These machines assume the responsibility of human and gradually expand the domain of their activities in industry. This paper is a presentation of the Sweeper Robot designed in the Robotic Laboratory of Iran University of Science and Technology. The original design of this ro...

An analysis tool is presented to design extension mechanisms that will enhance the motion capability of delta robots by means of enabling additional, rotational degrees of freedom. For this purpose, a tool is shown that is based on a task-oriented decision analysis process for designing such extension mechanisms. This is necessary, since assembly processes have significant effects on the requir...

Delta roboti Mechanical systems that allow a rigid body (called endeffector) to move with respect to a fixed base play a very important role in numerous applications. A rigid body in space can move in various ways, in translation or rotary motion. These are called its degrees of freedom (DOF). The position and the orientation of the end-effector (called its pose) can be described by its general...

In this paper, a multi-objective integrated trajectory planning method based on an improved butterfly optimization algorithm (IBOA) is proposed, to improve the dynamic performance of Delta parallel pickup robot in high-speed pick-and-place processes. The main objective present study positioning accuracy and running stability at high speeds accelerations. On one hand, intention ensure smooth mot...