Control design for distributed parameter systems usually makes use of either finite volume or finite element approximations of the governing partial differential equations (PDEs). the aim of using both finite volume a...
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Control design for distributed parameter systems usually makes use of either finite volume or finite element approximations of the governing partial differential equations (PDEs). the aim of using both finite volume and finite element models is to obtain a finite-dimensional state-space representation of the dynamics which can be used directly for the design of feedback or feedforward controllers as well as state observers. However, finite volume models only provide a coarse description of flow and storage variables since these are assumed to be piecewise homogeneous in the corresponding volume elements. In contrast, finite element models exploit parameterizable ansatz functions such as polynomials for each element so that smooth representations of the before-mentioned quantities become possible. However, classical finite element techniques do not provide reliable measures for the quantification of the achievable approximation quality. this drawback is removed by the method of integrodifferential relations (MIDR). Simulations and experiments for the observer-based control of a spatially two-dimensional heat transfer process with distributed control inputs are presented in this paper to visualize differences between finite element models relying on the MIDR and finite volume representations.
the steady-state response of a nonlinear object, stimulated by sinusoidal signal, contains boththe sinusoidal components of the same pulsation and higher harmonics. In the case of a linear plant with complex poles, w...
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the steady-state response of a nonlinear object, stimulated by sinusoidal signal, contains boththe sinusoidal components of the same pulsation and higher harmonics. In the case of a linear plant with complex poles, working on the border of stability, a steady-state response of a sinusoidal input also contains the components with different pulsations. their amplitude and phase shifts are dependent both on the system parameters, the excitation signal and the initial conditions. Can be expect that this property allows to approximate the steady-state behavior of nonlinear object by steady-state response of linear model. Probably, the parameters of this model depend strongly on the amplitude and phase of the sinusoidal excitation. the paper attempts to approximation of the steady-state behavior of the nonlinear object by the steady state response of the linear model. the specified sinusoidal excitation with typical zero initial conditions were used. A similar mechanism is used in the describing function methods, and the proposed method can be treated as a part of a class of harmonic linearization methods. the methodology of the method is illustrated in three examples. In two cases the behavior of linear models quite accurately resembles the actual waveforms of the plant. these results seem of interest, although usefulness of such models is difficult to predict.
As the educational system is growing there is a lot of paperwork to do like completing different types of certificates, or traditional gradebook. the paper presents a different approach to facilitate and secure the wr...
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As the educational system is growing there is a lot of paperwork to do like completing different types of certificates, or traditional gradebook. the paper presents a different approach to facilitate and secure the writing of certificates or traditional gradebooks. this system uses a robot arm, RV-2AJ, which has a pen attached. the setups are easy to be made because they involve the reading of only three points for calibration which forms a right-angled triangle. After the calibration the robotic arm can write even if the writing surface is on an inclined plane, or the paper is rotated. this system is more secure than the one that uses the ink printer, because the movement of the robot arm to reproduce the font on the paper is unique. Another secure element is the embossing stamp. the embossing stamp is created by changing the pen with a needle. the needle creates small closed holes using a pattern in which the information used for writing is encrypted.
the paper describes a method of sensor condition testing based on processing of data measured by the sensor using a Gaussian mixture model with dynamic weights. the procedure is composed of two steps, off-line and on-...
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the paper describes a method of sensor condition testing based on processing of data measured by the sensor using a Gaussian mixture model with dynamic weights. the procedure is composed of two steps, off-line and on-line. In off-line stage, fault-free learning data are processed and described by a probabilistic mixture of regressive models (mixture components) including a transition table between active components. It is assumed that each component characterises one property of data dynamics and just one component is active in each time instant. In on-line stage, tested data are used for transition table estimation compared withthe fault-free transition table. the crossing of given level of difference announces a possible fault.
this paper presents the experimental implementation of a teleoperated endoscopic surgical manipulator system that uses PHANTOM Omni haptic device as the master. the 4-DOF, 2-PUU 2-PUS, endoscopic surgical parallel man...
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this paper presents the experimental implementation of a teleoperated endoscopic surgical manipulator system that uses PHANTOM Omni haptic device as the master. the 4-DOF, 2-PUU 2-PUS, endoscopic surgical parallel manipulator design is carried out using screw theory and Parallel virtual chain methodology to have larger bending angles and workspace volume. the master and slave devices of the teleoperation system are dissimilar in their kinematics and workspace volumes. A workspace mapping technique is implemented based on Position with Modied Rate Control to navigate through the slave workspace without annoying the user. To control the motion of the slave robot, a PID controller is used. the experimental results show the feasibility of the teleoperation surgical system using the 4-DOF parallel manipulator. Also, they indicate the efficiency of the implemented mapping technique and the designed controller to span the slave workspace with high dexterity and good tracking which allows the surgeon to perform the operation with high accuracy.
Reduced state-space models obtained by model order reduction methods must be accurate over the whole frequency range of interest and must also preserve passivity. In this paper, we propose multipoint reduction techniq...
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Reduced state-space models obtained by model order reduction methods must be accurate over the whole frequency range of interest and must also preserve passivity. In this paper, we propose multipoint reduction technique using reflective exploration for adaptively choosing the expansion points. the projection matrices obtained from the expansion points are merged to form the overall projection matrix. In order to obtain a more compact model the projection matrix is truncated based on its singular values. Finally, the reduced order model is obtained, while ensuring that the passivity of the reduced system is preserved during the reduction process.
Nowadays, in Human-Machine Interaction systems, the communication between user and the machine (robot, computer, etc.) may be performed using a graphical representation of human often called avatar. Such graphical for...
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Nowadays, in Human-Machine Interaction systems, the communication between user and the machine (robot, computer, etc.) may be performed using a graphical representation of human often called avatar. Such graphical form needs a realistic human motion synthesis mechanisms which are becoming more and more popular in the virtual environments. therefore the paper is focussed on the problem of facial motion modeling for interactive virtual humans using events-based interaction rules. First, the most frequent emotional states and two types of personalities have been selected. For both personalities the transitions of the emotional states have been performed based on the motion probabilities. then, for animation process a set of the facial expression subtypes has been introduced. In such case it is possible to get a quite natural reactions of the avatar for various emotional states. Also, the transition probabilities have been defined for sub-states. Having obtained transition probabilities, a temporal duration of emotional state have been calculated. Finally, the architecture of the system for interaction between user and avatar based on facial animation modeling has been proposed.
Control design of spatially distributed thermal systems is a task that is necessary for a large variety of engineering applications. Early lumping techniques, that are applicable in this case, follow the methodology o...
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Control design of spatially distributed thermal systems is a task that is necessary for a large variety of engineering applications. Early lumping techniques, that are applicable in this case, follow the methodology of first discretizing the infinite-dimensional system model and subsequently using the discretized model for a finite-dimensional control design. For that purpose, the governing partial differential equations are commonly reduced to a finite-dimensional set of ordinary differential equations. In this paper, the corresponding task is solved by an optimization-based version of the Method of Integro-Differential Relations (MIDR). On the one hand, the MIDR allows one to quantify and systematically influence the approximation quality and, on the other hand, to use the resulting models directly for control and state observer design. In the following, the MIDR is applied to a fundamental problem of linear heat transfer in tube-like structures for which cylindrical coordinates are a suitable choice for modeling the dynamic behavior in all three space directions. Illustrative simulation results of fundamental control and state estimation approaches conclude this paper. these simulation results serve as the basis for a future experimental validation of the presented modeling techniques on a laboratory test rig that is currently being built up at the Chair of Mechatronics at the University of Rostock.
A dynamic control policy with optimized dynamics is explored for its use in a model predictive control (MPC) algorithm for a nonlinear system modeled with a feedforward neural network. the nonlinear system is expresse...
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ISBN:
(纸本)9781479952007
A dynamic control policy with optimized dynamics is explored for its use in a model predictive control (MPC) algorithm for a nonlinear system modeled with a feedforward neural network. the nonlinear system is expressed as a polytopic quasi-linear-parameter-varying (quasi-LPV) system over a region of the state-input space and the dynamics of the policy are allowed to depend on the time-varying parameter of the quasi-LPV model. the policy dynamics are optimized off-line to obtain an enlarged domain of attraction which matches withthe state-input region over which the polytopic approximation of the system holds good. A complete MPC algorithm using the dynamic policy as the terminal policy ensures stabilization and improved performance over a larger domain without a larger horizon length.
In this paper comparison of the two innovative signal processing methods for analysis of both EEG and EMG biomedical signals is in short presented. the reason for that is caused by the fact, that nowadays the broad an...
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In this paper comparison of the two innovative signal processing methods for analysis of both EEG and EMG biomedical signals is in short presented. the reason for that is caused by the fact, that nowadays the broad analysis of various biomedical signals is extremely popular. the first method presented in this paper relies on kernel density estimators application. Implementation of such method enables construction of densitograms for the examined bio-signals. One of the biggest advantages of this method is that it allows to obtain statistically filtered signals, which results in making the whole signal processing task significantly quicker. the second method described in this paper is based on basic mathematical operations only. Despite its simplicity the whole process can be implemented on almost any hardware platform, including those with very limited computational capabilities. Also it makes the task quick. In accordance withthe conducted experiments - the method is also efficient and as it can also be implemented on embedded platform and the algorithm can be rewritten in any programming language, the potential application of this method is wide.
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