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Author

Asokan Thondiyath

Other affiliations: Intuitive Surgical
Bio: Asokan Thondiyath is an academic researcher from Indian Institute of Technology Madras. The author has contributed to research in topics: Robot & Control theory. The author has an hindex of 9, co-authored 70 publications receiving 226 citations. Previous affiliations of Asokan Thondiyath include Intuitive Surgical.


Papers
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Proceedings ArticleDOI
21 Feb 2018
TL;DR: This controller is implemented for the depth control of an AUV with a 'Variable Buoyancy Engine (VBE)' and is found to have better performance as compared to the LQR and CDM.
Abstract: Although the 'Coefficient Diagram Method (CDM)' can generate a stable controller which is robust and give the desired performance, the optimality and cost function are not yet under consideration. Herein, we design and develop an optimal controller for the depth control of an 'Autonomous Underwater Vehicle (AUV)' by analyzing a 'Linear Quadratic Regulator (LQR)' based controller using the CDM. The coefficient diagrams of conventional LQR controller and CDM controller are analyzed and the parameters to design an optimal LQR controller are identified. This controller is implemented for the depth control of an AUV with a 'Variable Buoyancy Engine (VBE)' and is found to have better performance as compared to the LQR and CDM. The objective here is to reduce the control efforts needed for depth control. Finally, we report the detailed theoretical analysis and simulation results.

2 citations

Journal ArticleDOI
31 Aug 2012
TL;DR: An improved guidance algorithm for autonomous underwater vehicles (AUV) in 3D space for generating smoother vehicle turn during the course change at the way-points by modified way-point guidance by the line-of-sight method.
Abstract: This paper presents an improved guidance algorithm for autonomous underwater vehicles (AUV) in 3D space for generating smoother vehicle turn during the course change at the way-points. The way-point guidance by the line-of-sight (LOS) method has been modified for correcting the reference angles to achieve minimal calculation and smoother transition at the way-points. The algorithm has two phases in which the first phase brings the vehicle to converge to a distance threshold point on the line segment connecting the first two way-points and the next phase generates an angular path with smoother transition at the way-points. Then the desired angles are calculated from the reference and correction angles. The path points are regularly parameterized in the spherical coordinates and mapped to the Cartesian coordinates. The proposed algorithm is found to be simple and can be used for real time implementation. The details of the algorithm and simulation results are presented.

2 citations

01 Jan 2012
TL;DR: In this article, a real-time HIL setup for collision avoidance of an underactuated flat-fish type AUV using dSPACE DS1104 R&D controller and ControlDesk experiment software is presented.
Abstract: Hardware-in–the-Loop (HIL) simulations play a major role in the testing and verification of underwater robots and control strategies. Not many literatures are found for the real-time HIL verification of the control algorithms for Autonomous Underwater Vehicles (AUV) in 3D space. Most of the reported real-time simulators are virtual simulators and are mainly used for visualizing the AUV motion only. Hence a HIL test set up is required well before the actual vehicle is developed and deployed in the water. This paper discusses the development of HIL setup for collision avoidance of an underactuated flat-fish type AUV using dSPACE DS1104 R&D controller and ControlDesk experiment software. The results show that the dSPACE HIL setup is an effective tool for the verification of control algorithms and the developed collision avoidance algorithm can be used in real-time for the flat-fish type AUV. By using this developed dSPACE environment, the necessary improvements and modifications can be done before actually testing the vehicle and probability of test-bed vehicle collisions with obstacles can be greatly reduced. In this way, dSPACE products and solutions provide safe and reliable evaluation.

2 citations

Book ChapterDOI
01 Jan 2011
TL;DR: The meta-heuristic algorithm proposed here solves the task allocation problems with the characteristics like each task requires a certain amount of resources and each robot has a finite capacity of resource to be shared between the tasks it is assigned.
Abstract: This paper presents an improved algorithm for solving the complex task allocation problem in constrained multiple robot cooperative tasks. The existing multiple robot task allocation mechanisms do not discuss much about complex tasks, instead they treat tasks as simple, indivisible entities. Complex tasks are tasks that can be decomposed into a set of subtasks and so can be executed by several possible ways. The goal of cooperative task allocation algorithm for multiple mobile robots is to find which robot should execute which task in order to maximize the global efficiency and minimize the cost. Some factors such as benefit, cost, resources, and time should be considered during the course of task allocation. The meta-heuristic algorithm proposed here solves the task allocation problems with the characteristics like each task requires a certain amount of resources and each robot has a finite capacity of resource to be shared between the tasks it is assigned. The cost of solution which includes static costs when using robots, assignment cost, and communication cost between the tasks if they are assigned to different robots are also taken into account in developing the solution. A peer search scheme algorithm for solving the constrained task allocation problem is presented. Computational experiments using this algorithm have shown that the proposed method is superior in terms of computation time and solution quality.

2 citations


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Posted Content
TL;DR: Deming's theory of management based on the 14 Points for Management is described in Out of the Crisis, originally published in 1982 as mentioned in this paper, where he explains the principles of management transformation and how to apply them.
Abstract: According to W. Edwards Deming, American companies require nothing less than a transformation of management style and of governmental relations with industry. In Out of the Crisis, originally published in 1982, Deming offers a theory of management based on his famous 14 Points for Management. Management's failure to plan for the future, he claims, brings about loss of market, which brings about loss of jobs. Management must be judged not only by the quarterly dividend, but by innovative plans to stay in business, protect investment, ensure future dividends, and provide more jobs through improved product and service. In simple, direct language, he explains the principles of management transformation and how to apply them.

9,241 citations

01 Jan 2016
TL;DR: In this paper, the authors describe how to download and install guidance and control of ocean vehicles in the house, workplace, or perhaps in your method can be all best place within net connections.
Abstract: By searching the title, publisher, or authors of guide you in reality want, you can discover them rapidly. In the house, workplace, or perhaps in your method can be all best place within net connections. If you objective to download and install the guidance and control of ocean vehicles, it is utterly easy then, past currently we extend the colleague to buy and make bargains to download and install guidance and control of ocean vehicles therefore simple!

611 citations

Patent
31 Mar 2015
TL;DR: In this paper, a surgical tool with an elongated shaft having a proximal end and distal end is described, where an effector body includes a plurality of motor interfaces for driving the plurality of effector mechanisms.
Abstract: A surgical tool having an elongated shaft having a proximal end and distal end. A surgical end effector is located about the distal end. The surgical end effector has a plurality of effector mechanisms comprising a plurality of degree of freedoms. An effector body is located at the proximal end. The effector body includes a plurality of motor interfaces for driving the plurality of effector mechanisms. A transmission is coupled to the effector body

446 citations

Journal ArticleDOI
01 Apr 2019
TL;DR: This work proposes a novel, simpler, yet effective morphing design for quadrotors consisting of a frame with four independently rotating arms that fold around the main frame and demonstrates the first work showing stable flight without requiring any symmetry of the morphology.
Abstract: The recent advances in state estimation, perception, and navigation algorithms have significantly contributed to the ubiquitous use of quadrotors for inspection, mapping, and aerial imaging. To further increase the versatility of quadrotors, recent works investigated the use of an adaptive morphology, which consists of modifying the shape of the vehicle during flight to suit a specific task or environment. However, these works either increase the complexity of the platform or decrease its controllability. In this letter, we propose a novel, simpler, yet effective morphing design for quadrotors consisting of a frame with four independently rotating arms that fold around the main frame. To guarantee stable flight at all times, we exploit an optimal control strategy that adapts on the fly to the drone morphology. We demonstrate the versatility of the proposed adaptive morphology in different tasks, such as negotiation of narrow gaps, close inspection of vertical surfaces, and object grasping and transportation. The experiments are performed on an actual, fully autonomous quadrotor relying solely on onboard visual-inertial sensors and compute. No external motion tracking systems and computers are used. This is the first work showing stable flight without requiring any symmetry of the morphology.

205 citations

Journal ArticleDOI
TL;DR: A detailed comparison of various design features of fish-inspired robots reported in the past decade is presented, believing that by studying the existing robots, future designers will be able to create new designs by adopting features from the successful robots.
Abstract: Underwater robot designs inspired by the behavior, physiology, and anatomy of fishes can provide enhanced maneuverability, stealth, and energy efficiency. Over the last two decades, robotics researchers have developed and reported a large variety of fish-inspired robot designs. The purpose of this review is to report different types of fish-inspired robot designs based upon their intended locomotion patterns. We present a detailed comparison of various design features like sensing, actuation, autonomy, waterproofing, and morphological structure of fish-inspired robots reported in the past decade. We believe that by studying the existing robots, future designers will be able to create new designs by adopting features from the successful robots. The review also summarizes the open research issues that need to be taken up for the further advancement of the field and also for the deployment of fish-inspired robots in practice.

183 citations