Acousto-ultrasonic parameters (AU parameters) are applied to the inspection of laminated composite plates. In this paper, instead of wave velocity or attenuation, AU parameters which are based on the power spectrum of...
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Industrial designers and engineering designers: Can't we all just get along? Unfortunately, when push comes to shove, it's engineering that tends to win. How can schools better prepare industrial designers for...
Industrial designers and engineering designers: Can't we all just get along? Unfortunately, when push comes to shove, it's engineering that tends to win. How can schools better prepare industrial designers for the work force? engineering designers and industrial designers would get along much better if they shared common knowledge and common goals—long before they reached the workplace.
Modelling and control of rigid-flexible multibody systems is studied in this paper. As a specified application, a space robotic system with flexible appendages during a cooperative object manipulation task is consider...
Modelling and control of rigid-flexible multibody systems is studied in this paper. As a specified application, a space robotic system with flexible appendages during a cooperative object manipulation task is considered. This robotic system necessitates delicate force exertion by several end-effectors to move an object along a desired path. During such maneuvers, flexible appendages like solar panels may get stimulated and vibrate. This vibrating motion will cause some oscillatory disturbing forces on the spacecraft, which in turn produces error in the motion of the end-effectors of the cooperative manipulating arms. In addition, vibration control of these flexible members to protect them from fracture is another challenging problem in an object manipulation task for the stated systems. Therefore, the multiple impedance control algorithm is extended to perform an object manipulation task by such complicated rigid-flexible multibody systems. This extension in the control algorithm considers the modification term which compensates the disturbing forces due to vibrating motion of flexible appendages. Finally, a space free-flying robotic system which contains two 2-DOF planar cooperative manipulators, appended with two highly flexible solar panels, is simulated. Obtained results reveal the merits of the developed model-based controller which will be discussed.
There has been increased interest in use of pneumatic actuators in many fields, such as medical care and welfare. In particular, a pneumatic rubber actuator with soft material has many advantages such as low mass, fle...
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ISBN:
(纸本)9781467316439
There has been increased interest in use of pneumatic actuators in many fields, such as medical care and welfare. In particular, a pneumatic rubber actuator with soft material has many advantages such as low mass, flexibility, safety and user-friendliness. We therefore focus on pneumatic rubber actuators as a drive source of a rehabilitation device. This paper presents pneumatic rubber actuators for a rehabilitation device to prevent contractures of the finger joints. We propose two types of actuators. The fabrication of the actuators was based on molding silicon rubber. The actuators can not only operate in flexion and extension but can also twist and stretch out the finger. The actuators force and motion were characterized at different supply pressures. In addition, we investigated different possible methods of rehabilitation for fingers using the actuators. The metacarpophalangeal (MP) and the proximal interphalangeal (PIP) joint motion -were measured with the supply pressure of 150 kPa. The range of MP/PIP joint motion was from minus 3/9 degrees to 53/55 degrees. It was shown about 40 percent of its normal range. As a result, we confirmed the viability of the actuators for a finger rehabilitation device.
Simulation and analysis of the dynamic force-free control of robot arm with revolute joints are presented in this paper. Initially, modeling of dynamic force-free control method is described. Then simulation is carrie...
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ISBN:
(纸本)9781467322478
Simulation and analysis of the dynamic force-free control of robot arm with revolute joints are presented in this paper. Initially, modeling of dynamic force-free control method is described. Then simulation is carried out for single arm and two arm links robots by adopting Matlab/Simulink environment. The model characteristics of the force-free control is utilized to demonstrate the autonomous safety action being taken by the robot arm in particular instances such as;when the robot insisting on an undesirable operation or a collision with an obstacle or an unusual dragging along the working objects. Finally, simulation results are taken by adopting the force-free control on robot arms with industrial mechatronics controllers. Moreover, analysis of the force-free control is carried out by using real robot parameters throughout the simulations. Since the force-free control is about to deal with external forces given to the robot arm, it can be used to illustrate the cooperative control between a human and a robot arm by means of passive motion through external force.
For a freeway traffic system with strict repeatable pattern, iterative learning control (ILC) has been successfully applied to local ramp metering for a macroscopic freeway environment by formulating the original ramp...
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For a freeway traffic system with strict repeatable pattern, iterative learning control (ILC) has been successfully applied to local ramp metering for a macroscopic freeway environment by formulating the original ramp metering problem as an output tracking, disturbance rejection, and error compensation problem. In this paper, we address the freeway traffic ramp-metering system under a nonstrict repeatable pattern. ILC-based ramp metering and ILC add-on to ALINEA strategies are modified to deal with the presence of iteration-dependent parameters, iteration-dependent desired trajectory, and input constraints. Theoretical analysis and extensive simulations are used to verify the effectiveness of the proposed approaches.
This paper presents an efficient conflict resolution method for multiple aerial vehicles based on speed planning. The problem is assigning a speed profile to each aerial vehicle in real time such that the separation b...
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This paper presents an efficient conflict resolution method for multiple aerial vehicles based on speed planning. The problem is assigning a speed profile to each aerial vehicle in real time such that the separation between them is greater than a minimum safety value and the total deviation from the initial planned trajectories is minimized. Also, the arrival time of each aerial vehicle at the end waypoint of the trajectory is taken into account to solve the conflicts. The proposed method involves the use of appropriate airspace discretization. The method consists of two steps: a search tree step, which finds if it exists a solution; and an optimization step by solving a QP-problem, which minimizes a cost function. The paper also presents simulations for several scenarios and experiments that have been carried out in the multivehicle aerial testbed of the Center for advanced Aerospace Technologies (CATEC).
The thermal fatigue behaviour of an air plasma sprayed thermal barrier coating was investigated. And also the interfacial strengths of thermal barrier coated specimens subjected to thermal fatigue, as well as a retire...
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The thermal fatigue behaviour of an air plasma sprayed thermal barrier coating was investigated. And also the interfacial strengths of thermal barrier coated specimens subjected to thermal fatigue, as well as a retired TBC vane were also evaluated by means of an instrumented indentation machine. The results indicated that, （1） the TGO grew at the interface during thermal fatigue cycle as a function of the exposure time at elevated temperature; （2） the microcracks were initiated in the top coating and at the interface after thermal cycle tests; （3） the interfacial strength of TBC, which was evaluated by the indentation method, increased with the thermal cycles; （4） the interfacial strength of the retired TBC vane was almost equal with that of the as-sprayed TBC specimen.
A Norm-Optimal Iterative Learning control (NOILC) solution is developed for the problem when tracking is only required at a subset of isolated time points along the trial duration. Well-defined convergence properties ...
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Symbiotic computing services require big data from a huge number of sensor devices in order to detect the real-world, so a distributed database system which can handle the big data is required for symbiotic computing ...
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Symbiotic computing services require big data from a huge number of sensor devices in order to detect the real-world, so a distributed database system which can handle the big data is required for symbiotic computing system. In this paper, we propose a scalable structured p2p network which supports data aggregation. In the proposed p2p network, each node forwards partial statistical results to other nodes, and each node aggregates partial statistical results in order to calculate a complete statistical result. In the proposed p2p network, the data aggregation process does not need any specific protocols, so the communication cost of the extension mechanism is very low. We simulated the proposed p2p network by using a p2p network simulator. The simulation results indicate that the proposed data aggregation mechanism is effective enough.
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