Anirban Mazumdar

Massachusetts Institute of Technology, Cambridge, Massachusetts, United States

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Publications (15)5.77 Total impact

  • A. Mazumdar, H.H. Asada
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    ABSTRACT: A highly maneuverable, spheroid-shaped, underwater robot using appendage-free, multi-degree of freedom (DOF) propulsion technologies is presented. The vehicle is hydrodynamically unstable due to the Munk moment. The vehicle is stabilized by feedback control, rather than passive fins, which facilitates rapid turns and agile motions. The new design was motivated by nuclear reactor inspection and other applications where external appendages must be avoided. Two technical challenges are addressed in this paper. One is the development of a compact, multi-DOF propulsion system that generates multiaxis water jets and switches them rapidly. The other is the design of a jet configuration and control system that augments stability and achieves high maneuverability. A nonlinear hydrodynamic model is formulated, and its linearized dynamics are analyzed to attain insights into how jet direction influences controllability and stability. A prototype vehicle is built and used to verify these concepts. The integrated design method is implemented and shown to achieve stable motions, high maneuverability, and multidirectional capability.
    IEEE Transactions on Robotics 01/2014; 30(2):448-460. · 2.57 Impact Factor
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    ABSTRACT: In this paper we present a new type of spherical underwater robot that is completely smooth and uses jets to propel and maneuver. This robot is specifically designed for the direct visual inspection of water-filled infrastructure such as the inside of nuclear powerplants. The unique propulsion architecture consists of a single bidirectional centrifugal pump combined with two fluidic valves. The pump is used to produce a high velocity jet while the valves are used to quickly switch the jet between output ports. The spherical shape means that the robot is simple to model and control, maneuverable, and robust to collisions. The propulsion architecture is described in detail along with a rigid body model for maneuvering control. A novel valve PWM controller is used to achieve heading control, and the controller performance is confirmed with both simulation and experiments. Finally, experiments are used to illustrate the turning and diving performance of the robot.
    Robotics and Automation (ICRA), 2013 IEEE International Conference on; 01/2013
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    ABSTRACT: This paper describes the development of a robot that combines a powerful propeller with a pump-valve system that enables high maneuverability. In order to reduce size and improve turning performance, the design does not include external stabilizers such as fins. Therefore the robot is directionally unstable (yaw direction). In this work we outline the design of a linear stabilizing controller that does not require complicated flow sensors and instead simply uses angle and rate measurements. The linear controller was simulated and then implemented on a prototype robot. Preliminary results reveal that this stabilization method works to enable straight motions and is also able to reject substantial disturbances.
    ASME 2012 5th Annual Dynamic Systems and Control Conference joint with the JSME 2012 11th Motion and Vibration Conference; 10/2012
  • A. Mazumdar, H.H. Asada
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    ABSTRACT: Precision maneuvering is an important requirement for many underwater robotic applications such as inspecting infrastructure systems. Maneuvering, especially at low speeds, is complicated by the presence of nonlinearities such as asymmetries and dead zones. Current work at MIT's d'Arbeloff Laboratory has focused on the development of a compact maneuvering system for underwater vehicles using centrifugal pumps and high speed Coanda effect valves. This paper describes the development of a novel Valve PWM orientation control strategy designed specifically for this new maneuvering system. Simulations are used to show that simple linear control approaches are insufficient due to the presence of a dead zone. The Valve PWM system exploits the high speed nature of the valve and modulates the output force in order to produce small forces in a repeatable and predictable manner. A simple, intuition based approach for determining the PWM frequency and voltage amplitude is outlined and several optimal formulations are presented. A set of optimal parameters is selected and full nonlinear simulations are used to illustrate the effectiveness of the Valve PWM control system. Finally, preliminary experimental closed loop control data is used to emphasize that these concepts are both practical and applicable to physical robot systems.
    American Control Conference (ACC), 2012; 06/2012
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    ABSTRACT: There is an increasing need for the inspection of nuclear power plants worldwide. To access complex underwater structures and perform non-destructive evaluation, robots must be tetherless, compact, highly maneuverable, and have a smooth body shape with minimal appendages. A new water jet propulsion system using fluidic valves coupled with centrifugal pumps is developed for precision maneuvering. A hybrid control system that combines continuous pump regulation and discrete Pulse Width Modulation (PWM) of fluidic valves is proposed. This control scheme provides high accuracy, high bandwidth, and flexibility in maneuvering control. First, the functional requirements for nuclear power plant inspection are discussed, followed by the basic design concept of an inspection robot. Miniaturized Coanda-effect valves are designed and built based on CFD and mathematical analysis. The hybrid control system incorporating the pump/valve system is designed and tested. Experimental results illustrate that the hybrid control scheme holds substantial promise and is capable of very precise orientation control. Based on these, a full 4-DOF robot is designed, and its key components are described.
    Proceedings - IEEE International Conference on Robotics and Automation 01/2012;
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    ABSTRACT: This paper describes the performance of a new type of highly maneuverable underwater robot developed at MIT. The robot, titled “Omni-Egg,” is smooth, spheroidal, and completely appendage free. Propulsion is provided using a novel pump-jet system that can be completely built into the streamlined shell. No fins or stabilizers are used on the vehicle, and directional stability is instead achieved using feedback control. Experimental results show how the turning performance of this smooth design is superior to a similar one that uses fins to achieve stability. Due to this unique design the robot is capable of unique motions such as forward and reverse motions, high speed turning, and sideways translations. This type of robot is designed for tasks requiring a large degree of maneuverability within tight spaces. Some examples of such tasks include the inspection of water-filled infrastructure and the exploration of cluttered environments. Such applications have a high risk of collisions or snagging on obstacles, so a smooth outer shape is desirable. The vehicle is designed to be capable of 5 DOF, and surge, sway, heave, and yaw are all demonstrated in this paper. Pitch, the 5th DOF, remains under development.
    Oceans, 2012; 01/2012
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    ABSTRACT: System identification of limb mechanics can help diagnose ailments and can aid in the optimization of robotic limb control parameters and designs. An interesting fluid phenomenon--the Coandă effect--is utilized in a portable actuator to provide a stochastic binary force disturbance to a limb system. The design of the actuator is approached with the goal of creating a portable device which could be deployed on human or robotic limbs for in situ mechanical system identification. The viability of the device is demonstrated by identifying the parameters of an underdamped elastic beam system with fixed inertia and stiffness and variable damping. The nonparametric compliance impulse response yielded from the system identification is modeled as a second-order system and the resultant parameters are found to be in excellent agreement with those found using more traditional system identification techniques. The current design could be further miniaturized and developed as a portable, wireless, unrestrained mechanical system identification instrument for less intrusive and more widespread use.
    The Review of scientific instruments 03/2011; 82(3):035106. · 1.52 Impact Factor
  • Anirban Mazumdar, H. Harry Asada
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    ABSTRACT: A highly maneuver able, compact vehicle for underwater precision inspection of complex structures is presented. The vehicle will have no appendages such as rudders, screws, and other external thrusters, which might get tangled and interfere with the underwater structure in a cluttered environment. A multi-axis, integrated thruster mechanism using Coanda-effect high-speed valves for switching the direction of jets can be encapsulated in a compact, egg-shaped body. Compared to traditional screw thrusters, these valves have improved dynamic performance in switching the jet stream direction. Furthermore, the reaction forces and moments due to switching can be substantially reduced. First, the principle of Coanda effect water jet valves is introduced, and its governing equations are obtained. Optimal dimensions and parameters producing a maximum of thrust are obtained, and are experimentally verified. Multiple Coanda-effect valves are then integrated into a tree structure to create a multi-axis thrust mechanism. A simple planar proof of concept prototype is built and tested.
    IEEE International Conference on Robotics and Automation, ICRA 2011, Shanghai, China, 9-13 May 2011; 01/2011
  • Wayne Staats, Jesse Belden, Anirban Mazumdar, Ian Hunter
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    ABSTRACT: System identification (ID) of human and robotic limbs could help in diagnosis of ailments and aid in optimization of control parameters and future redesigns. We present a self-contained actuator, which uses the Coanda effect to rapidly switch the direction of a high speed air jet to create a binary stochastic force input to a limb for system ID. The design of the actuator is approached with the goal of creating a portable device, which could deployed on robot or human limbs for in situ identification. The viability of the device is demonstrated by performing stochastic system ID on an underdamped elastic beam system with fixed inertia and stiffness, and variable damping. The non-parametric impulse response yielded from the stochastic system ID is modeled as a second order system, and the resultant parameters are found to be in excellent agreement with those found using more traditional system ID techniques. The current design could be further miniaturized and developed as a portable, wireless, on-site multi-axis system identification system for less intrusive and more widespread use.
    11/2010;
  • Thomas W. Secord, Anirban Mazumdar, H. Harry Asada
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    ABSTRACT: Variable stiffness actuation and energy harvesting have been important yet separate challenges in robotics. Both functions are needed, however, for mobile robots on extended missions when actuators and generators must be used together. In this paper, we present a unique piezoelectric cellular system that combines motion generation and energy harvesting capabilities into a single, scalable device. Each of the discrete cellular units provides linear, contractile motion at 10% strain using the converse piezoelectric effect. These units may also be back-driven from environmental loading and thereby generate energy using the direct piezoelectric effect. Furthermore, each cell has the capability to toggle between a low stiffness ON state and a high stiffness OFF state, which allows an assembly of individual cells to tune both their static stiffness and structural resonant frequencies online. We demonstrate the effectiveness of our device for tuning both locomotion speed and the harvested power of an underwater flapping fin system.
    IEEE International Conference on Robotics and Automation, ICRA 2010, Anchorage, Alaska, USA, 3-7 May 2010; 01/2010
  • Anirban Mazumdar, H. Harry Asada
    Journal of Mechanisms and Robotics 01/2010; 2(3). · 0.97 Impact Factor
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    ABSTRACT: This paper focuses on the design and implementation of a percutaneous catheter-based device to provide physicians with an externally controlled tool capable of manipulating and cutting specific chordae tendinae within the hear to alleviate problems associated with some forms of mitral valve regurgitationt. In the United States alone, approximately 500,000 people develop ischemic or functional MR per year, and the chordae tendinae cutting procedure and device are needed because many patients do not have the required level of health necessary to survive open-heart surgery. A deterministic design process was used to generate several design concepts and then evaluate and compare each concept based on a set of functional requirements. A final concept to be alpha prototyped was then chosen, further developed, and fabricated. Experiments showed that the design was capable of locating and grabbing a chord and that ultrasound imaging is a viable method for navigating the device inside of the human body. Once contact between the chord and an RF ablator tip was confirmed, the chord was successfully ablated.
    Journal of Medical Devices 06/2009; 3(2):25001. · 0.71 Impact Factor
  • Anirban Mazumdar, H. Harry Asada
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    ABSTRACT: This paper describes the analysis, design, and implementation of an under-actuated robot control system for swing up motion. The robot, called the “Mag-Foot” robot, uses permanent magnets to adhere to steel surfaces. This robot uses a novel tilting foot design for locomotion and can swing over small obstacles using an underactuated swinging motion. Since the robot can only adhere to the surface using limited (and relatively small) magnetic forces, it may fall down due to the reaction forces caused by the swing-up motion. To prevent failure, an optimal swing up trajectory is designed so that the maximum reaction force during the trajectory is minimized. The trajectories are parameterized using sigmoids and are determined by solving the dynamic equations as a 2 point boundary value problem. Finally, experiments are performed to evaluate the validity of this approach. The results of these experiments are promising and illustrate the validity of our approach.
    ASME 2009 Dynamic Systems and Control Conference; 01/2009
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    Anirban Mazumdar, H. Harry Asada
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    ABSTRACT: A legged robot that moves across a steel structure is developed for steel bridge inspection. Powerful permanent magnets imbedded in each foot allow the robot to hang from a steel ceiling powerlessly. Although the magnets are passive, the attractive force is modulated by tilting the foot against the steel surface. This allows the robot to slide its feet along the surface using ¿Moonwalk¿ and ¿Shuffle¿ gait patterns. The robot can also detach its feet and swing them over small obstacles. These diverse walking patterns are created with a single servoed joint and 2 sets of simple locking mechanisms. Kinematic and static conditions are obtained for the under-actuated legged robot to perform each gait pattern safely and stably. A proof-of-concept prototype robot is designed, built, and tested. Experiments demonstrate the feasibility of the design concept and verify the analytical results.
    2009 IEEE/RSJ International Conference on Intelligent Robots and Systems, October 11-15, 2009, St. Louis, MO, USA; 01/2009
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    Anirban Mazumdar
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    ABSTRACT: Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2009. Includes bibliographical references (p. 83-84). The aging of America's steel bridges presents many challenges. Undetected cracks and corrosion can eventually lead to catastrophic failure. Due to the difficulties with inspecting existing bridges the use of mobile robots for steel bridge inspection has become an important area of research. This thesis describes the analysis, design, and implementation of a new approach to steel bridge inspection robots using tilting feet equipped with permanent magnets. This robot, titled "Mag-Feet", is capable of adhering to steel surfaces and can move along steel surfaces using a combination of three distinct gait modes. These three gait modes allow the robot to "Moonwalk" along horizontal surfaces, "Shuffle" up inclined surfaces, and "Swing" over small obstacles. The "Swing" motions present their own set of interesting challenges. Since the robot can only adhere to the surface using finite (and relatively small) magnetic forces, it may fall due to the reaction forces caused by the swing- up motion. To prevent failure modes, an optimal swing-up trajectory was designed so that the maximum reaction force during the trajectory was minimized. The trajectories were parameterized using sigmoids and were determined by solving the dynamic equations as a 2 point boundary value problem. Finally, a proof of concept prototype was constructed and was used to experimentally evaluate the design. These experiments illustrate the promise of the design and control approaches that were formulated. by Anirban Mazumdar. S.M.