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Mechatronics, IEEE/ASME Transactions on

Issue 2 • Date April 2014

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Displaying Results 1 - 25 of 44
  • Table of Contents

    Publication Year: 2014 , Page(s): C1 - C4
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  • IEEE/ASME Transactions on Mechatronics publication information

    Publication Year: 2014 , Page(s): C2
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  • Minimizing Energy Consumption of Wheeled Mobile Robots via Optimal Motion Planning

    Publication Year: 2014 , Page(s): 401 - 411
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (780 KB) |  | HTML iconHTML  

    This paper presents a new optimal motion planning aiming to minimize the energy consumption of a wheeled mobile robot in robot applications. A model that can be used to formulate the energy consumption for kinetic energy transformation and for overcoming traction resistance is developed first. This model will provide a base for minimizing the robot energy consumption through a proper motion planning. To design the robot path, the A* algorithm is employed to generate an energy-efficient path where a new energy-related criterion is utilized in the cost function. To achieve a smooth trajectory along the generated path, the appropriate arrival time and velocity at the defined waypoints are selected for minimum energy consumption. Simulations and experiments are performed to demonstrate the energy-saving efficiency of the proposed motion planning approach. View full abstract»

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  • Modeling and Sensorless Direct Torque and Flux Control of a Dual-Airgap Axial Flux Permanent-Magnet Machine With Field-Weakening Operation

    Publication Year: 2014 , Page(s): 412 - 422
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1196 KB) |  | HTML iconHTML  

    This paper presents the modeling and motion-sensorless direct torque and flux control of a novel dual-airgap axial-flux permanent-magnet machine optimized for use in flywheel energy storage system (FESS) applications. Independent closed-loop torque and stator flux regulation are performed in the stator flux ( x-y) reference frame via two PI controllers. This facilitates fast torque dynamics, which is critical as far as energy charging/discharging in the FESS is concerned. As FESS applications demand high-speed operation, a new field-weakening algorithm is proposed in this paper. Flux weakening is achieved autonomously once the y-axis voltage exceeds the available inverter voltage. An inherently speed sensorless stator flux observer immune to stator resistance variations and dc-offset effects is also proposed for accurate flux and speed estimation. The proposed observer eliminates the rotary encoder, which in turn reduces the overall weight and cost of the system while improving its reliability. The effectiveness of the proposed control scheme has been verified by simulations and experiments on a machine prototype. View full abstract»

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  • Dynamic Visual Servoing With Chaos Control for Redundant Robots

    Publication Year: 2014 , Page(s): 423 - 431
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (796 KB) |  | HTML iconHTML  

    This paper presents a new dynamic visual control system for redundant robots with chaos compensation. In order to implement the visual servoing system, a new architecture is proposed that improves the system maintainability and traceability. Furthermore, high performance is obtained as a result of parallel execution of the different tasks that compose the architecture. The control component of the architecture implements a new visual servoing technique for resolving the redundancy at the acceleration level in order to guarantee the correct motion of both end-effector and joints. The controller generates the required torques for the tracking of image trajectories. However, in order to guarantee the applicability of this technique, a repetitive path tracked by the robot-end must produce a periodic joint motion. A chaos controller is integrated in the visual servoing system and the correct performance is observed in low and high velocities. Furthermore, a method to adjust the chaos controller is proposed and validated using a real three-link robot. View full abstract»

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  • Damping and Tracking Control Schemes for Nanopositioning

    Publication Year: 2014 , Page(s): 432 - 444
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (887 KB) |  | HTML iconHTML  

    Fast and accurate tracking of reference trajectories is highly desirable in many nanopositioning applications, including scanning probe microscopy. Performance in common positioning stage designs is limited by the presence of lightly damped resonances and actuator nonlinearities such as hysteresis and creep. To improve the tracking performance in such systems, several damping and tracking control schemes have been presented in the literature. In this paper, six different control schemes are presented and applied to a nanopositioning system for experimental comparison. They include schemes applying damping control in the form of positive position feedback, integral resonant control, integral force feedback, and passive shunt-damping. Also, general pole placement in the form of model reference control, as well as a control scheme requiring only a combination of a low-pass filter and an integrator, is presented. The control schemes are fixed-structure, low-order control laws, for which few results exist in the literature with regard to optimal tuning. A practical tuning procedure for obtaining good tracking performance for five of the control schemes is, therefore, presented. Experimental results show that the schemes provide similar performance, and the main differences are due to the specific implementation of each scheme. View full abstract»

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  • New Geometric Approaches to the Analysis and Design of Stewart–Gough Platforms

    Publication Year: 2014 , Page(s): 445 - 455
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1699 KB) |  | HTML iconHTML  

    In general, rearranging the legs of a Stewart-Gough platform, i.e., changing the locations of its leg attachments, modifies the platform singularity locus in a rather unexpected way. Nevertheless, some leg rearrangements have been recently found to leave singularities invariant. Identification of such rearrangements is useful not only for the kinematic analysis of the platforms, but also as a tool to redesign manipulators avoiding the implementation of multiple spherical joints, which are difficult to construct and have a small motion range. In this study, a summary of these singularity-invariant leg rearrangements is presented, and their practical implications are illustrated with several examples including well-known architectures. View full abstract»

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  • Human Hand Motion Analysis With Multisensory Information

    Publication Year: 2014 , Page(s): 456 - 466
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1595 KB) |  | HTML iconHTML  

    In order to study and analyze human hand motions that contain multimodal information, a generalized framework integrating multiple sensors is proposed and consists of modules of sensor integration, signal preprocessing, correlation study of sensory information, and motion identification. Three types of sensors are integrated to simultaneously capture the finger angle trajectories, the hand contact forces, and the forearm electromyography (EMG) signals. To facilitate the rapid acquisition of human hand tasks, methods to automatically synchronize and segment manipulation primitives are developed in the signal preprocessing module. Correlations of the sensory information are studied by using Empirical Copula and demonstrate that there exist significant relationships between muscle signals and finger trajectories and between muscle signals and contact forces. In addition, recognizing different hand grasps and manipulations based on the EMG signals is investigated by using Fuzzy Gaussian Mixture Models (FGMMs) and results of comparative experiments show FGMMs outperform Gaussian Mixture Models and support vector machine with a higher recognition rate. The proposed framework integrating the state-of-the-art sensor technology with the developed algorithms provides researchers a versatile and adaptable platform for human hand motion analysis and has potential applications especially in robotic hand or prosthetic hand control and human-computer interaction. View full abstract»

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  • Design and Implementation of Model-Predictive Control With Friction Compensation on an Omnidirectional Mobile Robot

    Publication Year: 2014 , Page(s): 467 - 476
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (875 KB) |  | HTML iconHTML  

    This paper presents and discusses the implementation results of a model-predictive control (MPC) scheme with friction compensation applied to trajectory following of an omnidirectional three-wheeled robot. A cascade structure is used with an inverse kinematics block to generate the velocity references given to the predictive controller. Part of the control effort is used to compensate for the effects of static friction, allowing the use of efficient algorithms for linear MPC with constraints. Experimental results show that the proposed strategy is efficient in compensating for frictional effects as well as for tracking predefined trajectories. View full abstract»

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  • Bounded Assignment Formation Control of Second-Order Dynamic Agents

    Publication Year: 2014 , Page(s): 477 - 489
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (792 KB) |  | HTML iconHTML  

    A constructive design of bounded formation controllers is proposed to force N mobile agents with second-order dynamics to track N reference trajectories and to avoid collision between them. Instead of a prior assignation of the reference trajectories to the agents, optimal assignment algorithms are used to assign desired reference trajectories to the agents to obtain optimal criteria such as linear summation and bottleneck functions of the initial traveling distances of the agents. After the reference trajectories are optimally assigned, the bounded formation control design is based on a new bounded control design technique for second-order systems and new pairwise collision avoidance functions. The pairwise collision functions are functions of both relative positions and relative velocities of the agents instead of only relative positions as in the literature. The proposed results are illustrated on a group of underactuated omnidirectional intelligent navigators in a vertical plane. View full abstract»

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  • Robotic Gait Rehabilitation Trainer

    Publication Year: 2014 , Page(s): 490 - 499
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (900 KB) |  | HTML iconHTML  

    This paper presents the basic principle of operation, the mechanical design, and the control system of the Robotic Gait Rehabilitation (RGR) Trainer. This novel single-actuator mechatronic system targets secondary gait deviations affecting patterns of movement of the pelvis in stroke survivors. These deviations arise as compensatory movements associated with primary gait deviations, such as the lack of sufficient knee flexion during the swing phase of the gait cycle. Using an expanded impedance control strategy, the device generates a force field that affects the obliquity of the pelvis (rotation of the pelvis around the anteroposterior axis) via a lower body exoskeleton while the patient ambulates on a treadmill. Preliminary healthy human subject testing demonstrated that the RGR Trainer can effectively guide the pelvis in the frontal plane via force fields to alter pelvic obliquity. View full abstract»

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  • Design of a Novel 4-DOF Wrist-Type Surgical Instrument With Enhanced Rigidity and Dexterity

    Publication Year: 2014 , Page(s): 500 - 511
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1346 KB) |  | HTML iconHTML  

    This paper presents a new type of 4-degree-of-freedom (DOF) robotic surgical instrument for a minimally invasive surgical robot system. The forceps wrist mechanism was designed here on the basis of the 3-DOF parallel structure with three prismatic-spherical-revolute kinematic chains. The pitch and yaw motions of the moving platform generated the wrist rotational motions of the forceps. The axial translation of the parallel mechanism was converted into the forceps grasp motion by an inversion of the slider-crank mechanism. Furthermore, for a more dexterous movement of the forceps, a full revolution of the forceps for the axial rotation is also possible with the instrument. While the proposed instrument realized all the required DOFs of a forceps, the parallel structure of the wrist and the driving mechanism that was designed using only rod elements made the proposed instrument more reliable and rigid than other wire-driven instruments. The kinematic constraints and inverse kinematics of the proposed instrument were derived. Furthermore, the screw-based Jacobian was formulated geometrically, and the static force relation and the linear constraints on a twist were derived. Finally, a prototype of the proposed instrument with a diameter of 8 mm was introduced, and the performance of the prototype was verified through several experiments. View full abstract»

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  • Image-Based Visual Servoing of a 7-DOF Robot Manipulator Using an Adaptive Distributed Fuzzy PD Controller

    Publication Year: 2014 , Page(s): 512 - 523
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1122 KB) |  | HTML iconHTML  

    This paper is concerned with the design and implementation of a distributed proportional-derivative (PD) controller of a 7-degrees of freedom (DOF) robot manipulator using the Takagi-Sugeno (T-S) fuzzy framework. Existing machine learning approaches to visual servoing involve system identification of image and kinematic Jacobians. In contrast, the proposed approach actuates a control signal primarily as a function of the error and derivative of the error in the desired visual feature space. This approach leads to a significant reduction in the computational burden as compared to model-based approaches, as well as existing learning approaches to model inverse kinematics. The simplicity of the controller structure will make it attractive in industrial implementations where PD/PID type schemes are in common use. While the initial values of PD gain are learned with the help of model-based controller, an online adaptation scheme has been proposed that is capable of compensating for local uncertainties associated with the system and its environment. Rigorous experiments have been performed to show that visual servoing tasks such as reaching a static target and tracking of a moving target can be achieved using the proposed distributed PD controller. It is shown that the proposed adaptive scheme can dynamically tune the controller parameters during visual servoing, so as to improve its initial performance based on parameters obtained while mimicking the model-based controller. The proposed control scheme is applied and assessed in real-time experiments using an uncalibrated eye-in-hand robotic system with a 7-DOF PowerCube robot manipulator. View full abstract»

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  • Robust Discrete-Time MRAC With Minimal Controller Synthesis of an Electronic Throttle Body

    Publication Year: 2014 , Page(s): 524 - 537
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1848 KB) |  | HTML iconHTML  

    The electronic throttle body (ETB) is a fundamental actuator for regulating the air mass coming into an internal combustion engine; hence, it is used to control the engine torque in any modern drive-by-wire configuration. To cope with the nonlinear and discontinuous dynamics of this automotive device, in this paper a novel discrete-time model reference adaptive control (MRAC) method is designed and experimentally tested on an ETB installed on a 2-L engine. The control strategy extends the class of the minimal control synthesis (MCS) algorithms for discrete-time systems by adding an explicit discrete-time adaptive integral action and an adaptive robust term. An in-depth experimental investigation shows that the proposed control method is a viable solution as it is robust with respect to nonlinear torques acting on the plant, and it guarantees better performance than those provided by other MRAC strategies especially for small reference signals around the limp-home position where plant nonlinearities strongly affect the ETB dynamics. View full abstract»

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  • Design and Experimental Evaluations on Energy Efficient Control Allocation Methods for Overactuated Electric Vehicles: Longitudinal Motion Case

    Publication Year: 2014 , Page(s): 538 - 548
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (932 KB) |  | HTML iconHTML  

    The energy-efficient control allocation (EECA) scheme was previously proposed to distribute control efforts for overactuated systems by explicitly incorporating efficiency functions and working modes of redundant actuators. In this paper, three different real-time EECA schemes, namely adaptive EECA (A-EECA), KKT-based, and rule-based EECA, are proposed and compared for longitudinal speed tracking control of an electric ground vehicle (EGV) with two pairs of in-wheel motors. Two additional power resistor packs inserted in the dc circuits are applied to modify the operating efficiencies of two rear in-wheel motors, which are calibrated for experimental validations of the three EECA designs on a prototype EGV. In terms of the vehicle speed tracking performances, actuator dynamic responses, and total energy consumptions, both simulation and experimental results are evaluated and compared for the three distinct EECA methods. For the same EGV speed tracking effects, both simulation and experimental results indicate different power consumption savings are achieved by three EECA designs with different dynamic responses. View full abstract»

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  • Dynamic Path Planning for Inserting a Steerable Needle Into a Soft Tissue

    Publication Year: 2014 , Page(s): 549 - 558
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1003 KB) |  | HTML iconHTML  

    Steerable bevel-tip needles are widely used in modern, minimally invasive percutaneous procedures to reach specific areas inside the body. In this paper, we propose an optimized path planner for manipulating such steerable needles, which can generate the shortest path from the starting position to the target position with the least number of rotation times. The shortest traveling path produces less damage to the body, thus shortening the recovery period. We first investigate the insertion problem in a nondeformable environment, which is termed as the static environment in this paper. As the needle is flexible, the moving path is a curve. We propose to regulate the curved path within two parallel lines and then determine the optimal distance between the two parallel lines such that the generated moving path of the needle has the shortest length with the least number of needle rotations. We then investigate the insertion problem in a deformable environment, which is termed as the dynamic environment. Taking deformation and nonhomogenous properties of soft tissue into account, the target position and the radius of the curve path vary as the needle is inserted. By using a mass-spring model to formulate the deformable environment and a vision system to measure the time-varying radius of the curve, we propose a dynamic path planner that replans the path to adapt to the change of the target position and the curve radius. Simulations and experiments are performed to demonstrate the effectiveness of the proposed approach. View full abstract»

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  • A Nonlinear Current Control Method for Resistance Spot Welding

    Publication Year: 2014 , Page(s): 559 - 569
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1331 KB) |  | HTML iconHTML  

    Resistance spot welding (RSW) is one of the most commonly used methods in the manufacturing process for joining sheet metal together. This paper deals with the constant current control for RSW, which is the most common control strategy in actual applications. Since the process of RSW is nonlinear and time-varying, conventional control schemes do not yield satisfactory performance. To cope with this problem, a new control method is proposed in this paper. By solving the governing equation of the equivalent circuit of the RSW electrical system at each control cycle at its local coordinate frame, a nonlinear relationship between input and output variables is obtained. The relationship can be used to estimate an approximate value of the trigger time of the silicon-controlled rectifier for the next control cycle based on the information of the previous control cycle. In order to compensate the estimation error and improve the performance of the closed-loop system, a proportional-derivative (PD) controller is employed. Because the proposed controller regulates trigger time error instead of output current error, the parameters of the PD controller are easy to determine. The effectiveness of the proposed controller was verified through experiments under different conditions. Experimental results showed that the performance of the proposed controller was much better than that of a well-tuned proportional-integral-derivative controller. View full abstract»

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  • An Energy-Saving Pressure-Compensated Hydraulic System With Electrical Approach

    Publication Year: 2014 , Page(s): 570 - 578
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (960 KB) |  | HTML iconHTML  

    Mobile hydraulic systems are developed toward better control performance and higher energy efficiency. Pressure compensators, which govern the pressure drops over the control orifices, are widely used in multiactuator systems to improve their operability. However, additional energy is also dissipated in the compensators especially under the overrunning load conditions. This paper presents a novel energy-saving system, where the compensator is designed as a regeneration device consisting of a hydraulic motor and an electric generator. Then, hydraulic energy can be regenerated and pressure compensation function is realized by adapting the electromagnetic torque of the generator to the load as well. The close-loop control of the generator is designed by effective pressure drop estimation. The proposed energy-saving system and controller are implemented on an experimental platform of hybrid excavators which is equipped with an electric energy storage device. The experimental results show both good control performance and significant energy-saving effect. View full abstract»

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  • Modeling and Inverse Compensation of Nonmonotonic Hysteresis in VO _2 -Coated Microactuators

    Publication Year: 2014 , Page(s): 579 - 588
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1085 KB) |  | HTML iconHTML  

    Vanadium dioxide ( VO2) undergoes a thermally induced solid-to-solid phase transition, which can be exploited for actuation purposes. VO2-coated silicon cantilevers demonstrate abrupt curvature changes when their temperature is varied across the phase transition. Unlike the monotonic hysteresis phenomena observed in many other smart materials, the curvature-temperature hysteresis of VO2 actuators is nonmonotonic due to competing mechanisms associated with the material's phase transition and the different thermal expansion coefficients of the materials that form the bilayered cantilever. Motivated by the underlying physics, a novel model for the nonmonotonic hysteresis that combines a monotonic Preisach hysteresis operator and a quadratic operator is presented. A constrained least-squares scheme is proposed for model identification, and an effective inverse control scheme is presented for hysteresis compensation. For comparison purposes, a Preisach operator with a signed density function and a single-valued polynomial model are considered. Experimental results show that, for a 300- μm -long actuator, the largest modeling errors with the proposed model, the signed Preisach operator, and the polynomial approximation are 46.8, 80.3, and 483 m-1, respectively, over the actuated curvature range of [ -104, 1846] m-1. In addition, both the largest tracking error and root-mean-square error under the proposed inversion scheme are only around 10% of those under the polynomial-based inversion scheme. View full abstract»

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  • The Variable Stiffness Actuator vsaUT-II: Mechanical Design, Modeling, and Identification

    Publication Year: 2014 , Page(s): 589 - 597
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1474 KB) |  | HTML iconHTML  

    In this paper, the rotational variable stiffness actuator vsaUT-II is presented. This actuation system is characterized by the property that the apparent stiffness at the actuator output can be varied independently from its position. This behavior is realized by implementing a variable transmission ratio between the internal elastic elements and the actuator output, i.e., a lever arm with variable pivot point position. The pivot point is moved by a planetary gears mechanism, which acquires a straight motion from only rotations, thereby providing a low-friction transmission. The working principle details of the vsaUT-II are elaborated and the design is presented. The actuator dynamics are described by means of a lumped parameter model. The relevant parameters of the actuator are estimated and identified in the physical setup and measurements are used to validate both the design and the derived model. View full abstract»

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  • Superconducting Noncontact Device for Precision Positioning in Cryogenic Environments

    Publication Year: 2014 , Page(s): 598 - 605
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1270 KB) |  | HTML iconHTML  

    In this paper, a noncontact linear positioner based on superconducting magnetic levitation for high-precision positioning has been tested under cryogenic conditions (~20 K and ~10 -6Pa). The prototype is able to achieve submicrometric positioning resolution of 230 ± 30 nm RMS along a stroke of ±9 mm length with a current resolution of 15 μA, and a peak current requirement lower than ±500 mA. In addition, it was demonstrated that an open-loop control strategy could be used for positioning the moving part with the accuracy of the order of 1 μm. On the other hand, deviations of the slider position were found to be ±650 μrad for the pitch, lower than 100 μrad for the yaw, ±2000 μrad for the roll, and ±4 μm for the lateral run, all of them related to a full stroke motion. These results reveal a good performance of the device and demonstrate the potential of a new tool for applications, where high-precision positioning is required within a long range in cryogenic environments like far-infrared interferometry. View full abstract»

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  • Hybrid Power Plant Design for a Long-Range Dirigible UAV

    Publication Year: 2014 , Page(s): 606 - 614
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2253 KB) |  | HTML iconHTML  

    Unmanned aerial vehicle (UAV) dirigibles are well suited for surveillance and surveyance missions since they can hover and maintain lift without consuming energy and can be easily deflated for packaging and transportation. The challenge is developing a long endurance system while maintaining a low unit cost. This paper presents a novel hybrid power plant design that addresses both of these requirements. The lightweight design consists of a 4-stroke 14cc gasoline engine in-line with a brushless dc motor/generator and variable pitch propeller capable of producing a maximum power output of 250 W. A method was also developed to compare its performance and endurance to other power plant configurations that could be used in dirigible UAVs. Overall, the proposed hybrid power plant has 674% increase in energy density over that of a purely electric system, thereby proportionally increasing UAV flight time for the same power and weight. View full abstract»

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  • Design and Optimization of a Tubular Linear Electromagnetic Vibration Energy Harvester

    Publication Year: 2014 , Page(s): 615 - 622
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1042 KB)  

    This paper presents the design and optimization of tubular linear electromagnetic transducers (LETs) for the applications of large-scale vibration energy harvesting from vehicle suspensions, tall buildings, or long-span bridges. The LETs are composed of magnet and coil assemblies, which convert the vibration energy into electricity when moving relatively with each other. The parameters of the LETs, such as the thickness of the magnets in the axial direction and the thickness of the coils in the radial direction, are optimized using finite-element method to achieve high power density and damping density. Four LETs with different configurations namely, single-layer axial magnets and steel spacers, double-layer axial magnets and steel spacers, single-layer axial and radial magnets, double-layer axial and radial magnets are investigated for further improvement. It is found that the parameter optimization can increase the power density [W/m 3] of LETs to 3.8 times compared with the initial design by Zuo and coworkers, and the double-layer configuration with both radial and axial magnets can improve the power density up to 5.6 times, approaching to the energy dissipation rate of traditional oil dampers. A prototype using off-shelf axial NdFeB magnet is built and tested on a vibration shaker. The experiment results show that the prototype of 63.5 mm ( 2.5'') outer diameter and 305 mm (12 in) compressed length can harvest 2.8 W power at 0.11 m/s relative velocity and provide a damping coefficient of 940 N·s/m. It is estimated that average 26-33 W electrical power and 1680-2142 N·s/m damping coefficient can be achieved at 0.25 m/s root-mean-square velocity for different LETs of 3'' outer diameter and 12'' compressed length. View full abstract»

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  • Design and Actuator Selection of a Lower Extremity Exoskeleton

    Publication Year: 2014 , Page(s): 623 - 632
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1535 KB) |  | HTML iconHTML  

    Lower extremity exoskeletons are wearable robots that integrate human intelligence with the strength of legged robots. Recently, lower extremity exoskeletons have been specifically developed for transportation of disabled individuals. This paper summarizes the anthropomorphic design of a lower extremity exoskeleton named “walking supporting exoskeleton (WSE).” WSE has been developed to support some fundamental motions (walking, sitting, standing, etc.) of disabled individuals who lost leg muscular activities completely or partially. WSE has two degrees of freedom per leg which are powered by electrical actuators. This paper discusses critical design criteria considered in mechanical design and actuator selection of WSE. View full abstract»

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  • High-Accuracy Tracking Control of Hydraulic Rotary Actuators With Modeling Uncertainties

    Publication Year: 2014 , Page(s): 633 - 641
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (942 KB) |  | HTML iconHTML  

    Structured and unstructured uncertainties are the main obstacles in the development of advanced controllers for high-accuracy tracking control of hydraulic servo systems. For the structured uncertainties, nonlinear adaptive control can be employed to achieve asymptotic tracking performance. But modeling errors, such as nonlinear frictions, always exist in physical hydraulic systems and degrade the tracking accuracy. In this paper, a robust integral of the sign of the error controller and an adaptive controller are synthesized via backstepping method for motion control of a hydraulic rotary actuator. In addition, an experimental internal leakage model of the actuator is built for precise model compensation. The proposed controller accounts for not only the structured uncertainties (i.e., parametric uncertainties), but also the unstructured uncertainties (i.e., nonlinear frictions). Furthermore, the controller theoretically guarantees asymptotic tracking performance in the presence of various uncertainties, which is very important for high-accuracy tracking control of hydraulic servo systems. Extensive comparative experimental results are obtained to verify the high-accuracy tracking performance of the proposed control strategy. View full abstract»

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Aims & Scope

IEEE/ASME Transactions on Mechatronics encompasses all practical aspects of the theory and methods of mechatronics, the synergetic integration of mechanical engineering with electronic and intelligent computer control in the design and manufacture of industrial products and processes.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Okyay Kaynak
Department of Electrical and Electronic Engineering
Bogazici University
34342 Istanbul, Turkey
okyay.kaynak@boun.edu.tr