Heuristic based Task Allocation Algorithm for Multiple Robots Using Agents

AbstractTask allocation plays an important role in achieving high utilization of robots in multiple robots system. Existing task allocation schemes do not consider the dynamic and unpredictable nature of the environment and try to maximize the robot synergism in order to achieve various objectives such as minimization of turnaround time, make span, and cost. Here the methodology for task allocation using a set of static and mobile agents controlling a pool of multiple robots is presented and the objective is to minimize the turnaround time. The agents are capable of autonomous decision making and thus make autonomous task allocation decisions based on the changing status of the robot system. Also, the agents are used for delivering the task and collecting the results in two separate trips thus avoiding the waiting time, which in turn helps to minimize the turnaround time. The performance of the algorithm is assessed by comparing with other existing task allocation method. The numerical simulation results manifest that the proposed algorithm performs the best under different problem scales and connectivity

Autonomy for Robots: Design and Developmental Challenges (Keynote Address)

AbstractAutonomy for robots is one of the key requirement in any field robotic applications. Design and development of autonomous robots raises many challenges to the engineers and full autonomy for robots is still an unfinished job. In this key note address, some of the design challenges and implementation issues will be presented. Along with this, the design of an autonomous underwater robot for surveillance application will be presented as a case study

Robotic vehicle with side scanning sonar for underwater surveillance of shallow water reservoirs

Design and experimental investigations of a side scanning sonar system developed for scanning the underwater environments for shallow water applications is described in this paper. A self-propelled floating vehicle with two arrays of side looking sonar sensors and a data controller is designed as the scanning platform. Data from the sonar are sent through wireless mode to a computer and analyzed using special purpose software. Objects floating below the water level or lying on the bottom surface of still water reservoirs can be easily identified using this system. The water condition or other environmental factors have little effect on the quality of the scanned images. Design details of the vehicle and experimental results are presented

Empirical Mode Analysis for Characterization of Hand Tremor in the Design of Laparoscopic Tools1

International audienc

Empirical Mode Analysis for Characterization of Hand Tremor in the Design of Laparoscopic Tools

International audienc

A Novel Goal oriented Sampling Method for Improving the Convergence Rate of Sampling based Path Planning for Autonomous Mobile Robot Navigation

Autonomous Mobile Robots' performance relies on intelligent motion planning algorithms. In autonomous mobile robots, sampling-based path-planning algorithms are widely used. One of the efficient sampling-based path planning algorithms is the Rapidly Exploring Random Tree (RRT). However, the solution provided by RRT is suboptimal. An RRT extension known as RRT* is optimal, but it takes time to converge. To improve the RRT* slow convergence problem, a goal-oriented sampling-based RRT* algorithm known as GS-RRT* is proposed in this paper. The focus of the proposed research work is to reduce unwanted sample exploration and solve the slow convergence problem of RRT* by taking more samples in the vicinity of the goal region. The proposed research work is validated in three different environments with a map size of 384*384 and compared to the existing algorithms: RRT, Goal-directed RRT(G-RRT), RRT*, and Informed-RRT*. The proposed research work is compared with existing algorithms using four metrics: path length, time to find the solution, the number of nodes visited, and the convergence rate. The validation is done in the Gazebo Simulation and on a TurtleBot3 mobile robot using the Robotics Operating System (ROS). The numerical findings show that the proposed research work improves the convergence rate by an average of 33% over RRT* and 27% over Informed RRT*, and the node exploration is 26% better than RRT* and 20% better than Informed RRT*

Stereoscopic telepresence viewing system for remotely operated underwater robotic vehicle

This paper describes the design, structure, and preliminary evaluation of an experimental Telepresence Viewing System (TVS) for Underwater Robotic Vehicle (URV) application. The Telepresence Viewing System enables an automatic projection of properly prepared and adapted underwater stereoscopic video images from the video cameras of the URV, into the operator’s visual field. This helps the operator’s vestibular and kinesthetic sensations to be coupled to the visual information from the URV. The developed TVS is an active camera system, consisting of two video cameras, a video synchronizer and a multiplexer. These are applied to produce analog stereoscopic video images, which are further converted to VGA format and processed to derive flicker free stereo images. An adaptive camera convergence/divergence control system is incorporated in the system to reduce geometric distortions of the image. A zooming control feature also has been added to improve the eye comfort. These features have been tested and verified in limited human assessment, showing lower levels of eyestrain and operator discomfort. The system has also been demonstrated to overcome constraints imposed by URV design requirements

Empirical Mode Decomposition-based filtering for fatigue induced hand tremor in laparoscopic manipulation

International audienceFatigue induced hand tremor (FIT) is an unavoidable phenomenon, which substantially limits the accuracy of the surgical manipulation for long duration laparoscopic surgeries. Filtering intended motion from tremor is a challenging task as the properties of tremor change with increasing muscle fatigue levels. Muscle fatigue induced hand tremor has highly nonlinear and nonstationary characteristics that need a filtering strategy different from the conventional filters. Empirical Mode Decomposition (EMD) based filters have become popular in the recent past for its enhanced nonlinear signal handling capability. EMD based filtering strategy is case specific in nature as the EMD does not have any general analytical formulation unlike other (Kernel based) popular filtering techniques. In this work, we have addressed the tremor filtering issue with the help of EMD and the probability distribution characteristics analysis of Intrinsic Mode Functions (IMF) of the tremulous laparoscopic tool trajectory. A modified distribution asymmetry measure was employed to find out the threshold IMF for reconstruction of tremor free motion at different fatigue levels. In order to find the robustness of the proposed technique, the compensation strategy has been tested extensively on synthetic signal and experimentally acquired signals. Filtering threshold at different fatigue levels was also demonstrated for various subjects. Despite the time-varying properties of tremor, the proposed filtering strategy substantiates its efficacy to diminish the effect of tremor which was not possible by the conventional fixed cut-off filtering techniques

Dominant Component in Muscle Fatigue Induced Hand Tremor during Laparoscopic Surgical Manipulation

International audienceAccuracy of laparoscopic surgery gets affected by the hand tremor of the surgeons. Though cognitive load is inevitable in such activity which promotes tremor, muscle fatigue induced tremor is significant among the most important sources of tremor. Characteristic of fatigue induced hand tremor and its dominant directional properties are reported in this work. For a fixed laparoscopic tool grip with temporally synchronized predefined task protocols, characteristics of fatigue induced tremors have been studied. Dominant component of tremor was found to be in the sagittal plane in case of both static and dynamic tasks. In order to relate it with the muscle fatigue level, spectral properties of surface electromyography (SEMG) were also investigated simultaneously. A study of transient effect on tool positioning was also included, which conjointly advocates the other experimental results on fatigue induced hand tremor as well