A proof of safety is paramount for an autonomous robotic surgical system to ensure that it does not cause trauma to patients. However, a proof of safety is rarely constructed, as surgical systems are too complex to be...
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ISBN:
(纸本)9783319181264;9783319181257
A proof of safety is paramount for an autonomous robotic surgical system to ensure that it does not cause trauma to patients. However, a proof of safety is rarely constructed, as surgical systems are too complex to be dealt with by most formal verification methods. In this paper, we design a controller for motion compensation in beating-heart surgery, and prove that it is safe, i. e., the surgical tool is kept within an allowable distance and orientation of the heart. We solve the problem by simultaneously finding a control law and a barrier function. The motion compensation system is simulated from several initial conditions to demonstrate that the designed control system is safe for every admissible initial condition.
In situ vibration measurements are carried out on a a typical steam turbogenerator (TG) unit at the West Burton Power Plant UK during the steady state operation. A typical phenomenon of appearance of low frequencies i...
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ISBN:
(纸本)9783319099170
In situ vibration measurements are carried out on a a typical steam turbogenerator (TG) unit at the West Burton Power Plant UK during the steady state operation. A typical phenomenon of appearance of low frequencies in band of 7-12 Hz is observed mainly related to the vibration measurements on low pressure (LP) turbines bearing pedestals. This band of frequency observed to be modulating with vibration at the machine RPM (50 Hz) and its higher harmonics. The paper summaries the possible causes for such dynamic behaviour.
This paper describes the design and fabrication of a 2-DOF wrist mechanism suitable for fabrication with maximum dimension on the order of 2-4 mm. The design is based on the idea of 2 half-cylinders in contact such th...
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ISBN:
(纸本)9783319158624;9783319158617
This paper describes the design and fabrication of a 2-DOF wrist mechanism suitable for fabrication with maximum dimension on the order of 2-4 mm. The design is based on the idea of 2 half-cylinders in contact such that their axes lie orthogonal to each other. In that way, each cylinder can roll parallel to the other cylinder's axis, giving 2 rotational degrees of freedom. To constrain the cylinders' motion, unique gear teeth are designed that allow rolling motion in either orthogonal direction, but constrain all other motions. Contact can be guaranteed using a compressive force acting to push the cylinders together. We first demonstrate the design at centimeter scale using FDM 3D printing. Based on the smooth motion achieved, we fabricate a wrist with maximum dimension of 3 mm using layered sheets of carbon nanotube composite material. Each sheet is individually patterned using photolithography.
In this paper, the 3D virtual model and the prototype of an experimental bench designed and used to test endoprosthesis prototypes for elbow joint in flexion-extension and pronation-supination movements are presented....
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ISBN:
(纸本)9783319094106
In this paper, the 3D virtual model and the prototype of an experimental bench designed and used to test endoprosthesis prototypes for elbow joint in flexion-extension and pronation-supination movements are presented. The experimental tests were carried out on a group of nine healthy subjects and on the corpse prosthetic elbow. Experimental data for flexion-extension movement cycles were acquired using SimiMotion video system. The data files and the flexion-extension angle diagrams are obtained for all the subjects and for the corpse prosthetic elbow. The command programs in C++ for the performance of experimental tests on the bench are elaborated. A comparative experimental study of flexion-extension movement for healthy elbows and for the prosthetic corpse elbow joint fixed on the experimental bench is presented.
To date gearboxes remain one of the most important elements of virtually every power transmission system as far as a continuous operation of the shaft line is concerned. Any failure or breakdown may result in putting ...
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ISBN:
(纸本)9783319099170
To date gearboxes remain one of the most important elements of virtually every power transmission system as far as a continuous operation of the shaft line is concerned. Any failure or breakdown may result in putting the whole production line, supply chain or even peoples life in jeopardy. Endeavours to detect an incipient fault within the system serve multiple purposes from increasing the safety of the people responsible for operating the machines, through to decreasing running and operational costs, allowing time to plan for the inevitable repairs and making sure that the downtime of the machine is kept to an absolute minimum. This, in turn, makes this branch of condition monitoring of rotating machinery one of the most intensively studied. The Empirical Mode Decomposition (EMD) is a relatively new method of signal decomposition, which breaks the original signal up into a number of so-called Intrinsic Mode Functions (IMFs). The decomposition represents a type of adaptive filtering which outputs a number of IMFs which, acquired according to two strict criteria, contain portions of the filtered version of the original signal and so can carry different information about the content of the signal. EMD has already been used in the field of condition monitoring of rotating machinery, but the selection of the optimal IMF for the task often requires the experience of a condition monitoring specialist. This paper proposes a frequency-based tool for automatic selection of the IMF that is best suited for the detection of localized gear tooth faults.
In this paper, an accurate envelope analysis algorithm is developed for a wireless sensor node. Since envelope signals employed in condition monitoring often have narrow frequency bandwidth, the proposed algorithm dow...
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ISBN:
(纸本)9783319099170
In this paper, an accurate envelope analysis algorithm is developed for a wireless sensor node. Since envelope signals employed in condition monitoring often have narrow frequency bandwidth, the proposed algorithm down-samples and cascades the analyzed envelope signals to construct a relatively long one. Thus, a relatively higher frequency resolution can be obtained by calculating the spectrum of the cascaded signal. In addition, a 50 % overlapping scheme is applied to avoid the distortions caused by Hilbert transform based envelope calculation. The proposed method is implemented on a wireless sensor node and tested successfully for detecting an outer race fault of a rolling bearing. The results show that the frequency resolution of the envelope spectrum is improved by 8 times while the data transmission remains at a low rate.
The paper presents the results of many investigations to make clear how the different parameters of tensile load which will possibly control the use of a strain sensor made of the conductive silicone rubber affect the...
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ISBN:
(纸本)9783319158624;9783319158617
The paper presents the results of many investigations to make clear how the different parameters of tensile load which will possibly control the use of a strain sensor made of the conductive silicone rubber affect the electrical properties of this material. In order to clarify the behavior of this conductive silicone rubber during the cyclic load other tests are implemented on several specimens for each test to compare their behavior. The compliant systems with such sensors do not require mounting, and also they can be miniaturized. The target of these investigations is to use the conductive silicone rubber as a strain sensor by means of changing its electrical properties depending on the tensile load under different conditions.
The determination of whirling frequencies of high speed turbines is always challenging in rotor dynamics. The natural frequencies of a Jeffcott rotor are split in the presence of gyroscopic effect. It is quite well kn...
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ISBN:
(纸本)9783319099170
The determination of whirling frequencies of high speed turbines is always challenging in rotor dynamics. The natural frequencies of a Jeffcott rotor are split in the presence of gyroscopic effect. It is quite well known that the lower branch corresponds to the backward whirl and the upper branch corresponds to forward whirl. The forward whirl mode of the rotor has been observed experimentally, however, the backward whirl has not been observed. In this study it is shown that the backward whirl can be observed when the rotor is coasting down to rest from above the critical speed corresponding to the backward whirl. In order to illustrate the forward and the backward critical speeds of a simple Jeffcott rotor, the natural frequencies are obtained analytically for the second natural frequency of the system because of the large gyroscopic effect present in that mode. An experimental set up was used to verify the presence of backward whirl while the rotor is coasting down to rest. The rotor is also simulated using finite element method by ANSYS, and Campbell diagram is plotted. The analytical, experimental and ANSYS simulations confirm the existence of the backward whirl when the rotor is coasting down.
In the present work dynamic analysis of multilayered sandwich beam with MRE core has been carried out. Finite element model has been developed for the multilayered sandwich beam with alternate stiff metallic and soft ...
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ISBN:
(纸本)9783319099170
In the present work dynamic analysis of multilayered sandwich beam with MRE core has been carried out. Finite element model has been developed for the multilayered sandwich beam with alternate stiff metallic and soft MRE core materials. Natural frequencies have been determined for 5 and 7 layered beams at different magnetic fields considering three different boundary conditions. Also the effect of increase in number of layers on modal frequencies, time and frequency responses have been studied which show that damping of multilayer beam occurs faster than the 3 layered sandwich beams with equivalent material.
We present in this paper the process allowing to create a cable-driven parallel robot (CDPR) simulation within the XDE software environment in C++ language. The elementary classes constituting a CDPR are shown with th...
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ISBN:
(纸本)9783319094892;9783319094885
We present in this paper the process allowing to create a cable-driven parallel robot (CDPR) simulation within the XDE software environment in C++ language. The elementary classes constituting a CDPR are shown with their constructor specificities. The winches, the pulleys, the cable fastenings and the platform are presented. The parameterization of elements such as the cable material characteristics, structure and size are detailed. An interface between the XDE cable-driven parallel robot simulator and a Matlab/Simulink controller have been developed. Inputs and outputs are exchanged between the controller and the simulated cable-driven robot, exactly as it is done with a physical robot.
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