Soheil Keshmiri

A centralized framework to multi-robots formation control: theory and application

This paper presents a geometric approach to multirobots group formation with connectivity preservation (from a graph-theoretic perspective) among group members. The controller demonstrates consistency among different formations, as well as stability while performing dynamic switching between formations. Inter-robots collision avoidance is delivered through formation preservation, while permitting high degree of formation re-adjustability. It has been proven that such formation approach would result into complete, isomorphic formations (with regards to its first and second isogonic) with edge connectivity λ(G) = 1/4n(n-1), and a unique, shortest connectivity link among group members. The complete connectivity along with the isomorphic property of the formations would, in essence, not only guarantee that the communication among the robotic agents will be preserved, but also relax the topological requirements for message passing among group members that might be needed while switching between different formations. In addition, the existence of the inter-robot shortest connectivity link at the group level, would ease the message routing once the information sharing among all the members of the group is necessary.

Regression Analysis of Multi-Rendezvous Recharging Route in Multi-Robot Environment

One of the crucial issue in the field of autonomous mobile robotics is the vitality of energy efficiency of robots and the entire system they form. By efficiency here we refer to ability of robots (or the system in which they are deployed) to maintain their survival throughout the course of the operation so as to provide themselves with the opportunity of attaining energy once needed. In this paper, issue of recharging of a group of autonomous worker robots in their working environment has been addressed. To deliver the objective, a tanker robot’s planner, capable of determining an energy supply route based on regression analysis techniques, has been implemented. Specifically we have examined the practicality of ordinary and weighted least squares (OLS and WLS respectively) as well as orthogonal least absolute values (ORLAV) regressions for recharging route computation (hence the terms Least Square Recharging Route (LSRR) and Orthogonal Recharging Route (ORR)). Studies were conducted (while examining OLS and WLS techniques) to analyze the effect of various uncertainties which may exist in location information of the robots with regards to the recharging route. It has been proven that ORLAV based planner may result to a recharging route that minimizes the cumulative sum of worker robots distance traversal during the recharging process, irrespective of tanker location. Simulations in both, environment with and without obstacles, have been conducted to examine the practicality of the techniques in contrast with fixed charging station scenario. Appropriate graphs, diagrams and tables, representing the results obtained in simulations are provided for illustrative comparisons among different techniques.

Multi-robot, dynamic task allocation: a case study

This article presents a subgrouping approach to the multi-robot, dynamic multi-task allocation problem. It utilizes the percentile values of the distributional information of the tasks to reduce the task space into a number of subgroups that are equal to the number of robotic agents. The subgrouping procedure takes place at run-time and at every designated decision-cycle to update the elements of these subgroups using the relocation information of the elements of the task space. Furthermore, it reduces the complexity of the decision-making process proportional to the number of agents via introduction of the virtual representatives for these subgroups. The coordination strategy then uses the votes of the robotic agents for these virtual representatives to allocate the available subgroups. We use the elapsed time, the distance traveled, and the frequency of the decision-cycle as metrics to analyze the performance of this strategy in contrast to the prioritization, the instantaneous, and the time-extended coordination strategies.

On Confinement of the Initial Location of an Intruder in a Multi-robot Pursuit Game

Research in multi-robot pursuit-evasion demonstrates that three pursuers are sufficient to capture an intruder in a polygonal environment. However, this result requires the confined of the initial location of the intruder within the convex hull of the locations of the pursuers. In this study, we extend this result to alleviate this convexity through the application of a set of virtual goals that are independent of the locations of the pursuers. These virtual goals are solely calculated using the location information of the intruder such that whose locations confine the intruder within their convex hull at every execution cycle. We propose two strategies to coordinate the pursuers. They are the agents votes maximization and the profile matrix permutations strategies. We consider the time, the energy expended, and the distance traveled by the pursuers as metrics to analyze the performance of these strategies in contrast to three different allocation strategies. They are the probabilistic, the leader-follower, and the prioritization coordination strategies.

Isogonic Formation with Connectivity Preservation for a Team of Holonomic Robots in a Cluttered Environment

A geometric approach to multi-robots group formation with connectivity preservation(from a graph-theoretic perspective) among group members has been presented. It has been proven that such formation approach would result into a unique shortest connectivity link among group members which would not only guarantee the communication preservation among the robotic agents but also facilitate the message passing and routing among the group members once needed.

AN OPTIMAL ORTHOGONAL RECHARGING ROUTE PLANNER: A MULTI-ROBOTS, MULTI-RENDEZVOUS RECHARGING SCHEME

The issue of recharging a group of worker robots in their working environment has been tackled. For this purpose, a special purpose tanker robot has been devised with a planner, capable of generating recharging route that minimizes the cumulative sum of orthogonal distances of worker robots from their current locations to their corresponding recharging rendezvous locations along the recharging route (hence the term Orthogonal Recharging Route or ORR Planner). It has been proven that the ORR planner will result into a recharging route that minimizes the total worker robots distance traversal for recharging, irrespective of location of charging station/tanker. Experiments have been conducted to examine the practicality of the technique in contrast with scenarios of fixed charging station, as well as results of previous work based on Ordinary and Weighted Least Squares (OLS and WLS respectively) regressions. Results obtained in simulations are provided for illustrative comparison purpose among the different techniques.Copyright