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Showing papers by "Asokan Thondiyath published in 2014"


Proceedings ArticleDOI
01 Jan 2014
TL;DR: 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.
Abstract: Accuracy 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.

14 citations


Journal ArticleDOI
TL;DR: A heuristic search-based task allocation algorithm for the task processing in heterogeneous multiple robot system, by maximizing the efficiency in terms of both communication and processing cost.
Abstract: The current trends in the robotics field have led to the development of large-scale multiple robot systems, and they are deployed for complex missions. The robots in the system can communicate and interact with each other for resource sharing and task processing. Many of such systems fail despite the availability of necessary resources. The major reason for this is their poor coordination mechanism. Task planning, which involves task decomposition and task allocation, is paramount in the design of coordination and cooperation strategies of multiple robot systems. Task allocation mechanism allocates the task in a mission to the robots by maximizing the overall expected performance, and thereby reducing the total allocation cost for the team. In this paper, we formulate a heuristic search-based task allocation algorithm for the task processing in heterogeneous multiple robot system, by maximizing the efficiency in terms of both communication and processing cost. We assume a set of decomposed tasks of a mission, which needs to be allocated to the robots. The near-optimal allocation schemes are found using the proposed peer structure algorithm for the given problem, where the number of the tasks is more than the robots present in the system. The cost function is the summation of static overhead cost of robots, assignment cost, and the communication cost between the dependent tasks, if they are assigned to different robots. Experiments are performed to verify the effectiveness of the algorithm by comparing it with the existing methods in terms of computational time and quality of solution. The experimental results show that the proposed algorithm performs the best under different problem scales. This proves that the algorithm can be scaled for larger system and it can work for dynamic multiple robot system.

8 citations


Journal ArticleDOI
01 Jan 2014
TL;DR: The results show that the proposed MPPF method is very effective for obstacle avoidance in 3D space and can be used in the real-time control of the AUV.
Abstract: This paper discusses a real-time obstacle avoidance algorithm and its implementation for an underactuated flat-fish type autonomous underwater vehicle (AUV) in 3D space. The algorithm has been developed using multi-point potential field (MPPF) method and its real-time testing is carried out using hardware-in-loop (HIL) simulations. In MPPF method, a region of predefined radius on a hemisphere in the positive x-axis around the bow of an AUV is discretized into equiangular points with centre as the current position. By determining the point at which the minimum total potential exists, the vehicle can be moved towards that point. Here the analytical gradient of the total potential function is not calculated as it is not essentially required for moving the vehicle to the next position. The MPPF method is interfaced with dynamic model of an underactuated flat-fish type AUV and it is tested and verified using HIL simulation tool. The details of the dynamics of AUV, MPPF method and its implementation, development of HIL test bench and the simulation results are presented in this paper. The results show that the proposed MPPF method is very effective for obstacle avoidance in 3D space and can be used in the real-time control of the AUV.

8 citations