Predicting the motions of rigid objects under contacts is a necessary precursor to planning of robot manipulation of objects. On the one hand physics based rigid body simulations are used, and on the other learning ap...
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ISBN:
(纸本)9781479969357
Predicting the motions of rigid objects under contacts is a necessary precursor to planning of robot manipulation of objects. On the one hand physics based rigid body simulations are used, and on the other learning approaches are being developed. The advantage of physics simulations is that because they explicitly perform collision checking they respect kinematic constraints, producing physically plausible predictions. The advantage of learning approaches is that they can capture the effects on motion of unobservable parameters such as mass distribution, and frictional coefficients, thus producing more accurate predicted trajectories. This paper shows how to bring together the advantages of both approaches to achieve learned simulators of specific objects that outperform previous learning approaches. Our approach employs a fast simplified collision checker and a learning method. The learner predicts trajectories for the object. These are optimised post prediction to minimise interpenetrations according to the collision checker. In addition we show that cleaning the training data prior to learning can also improve performance. Combining both approaches results in consistently strong prediction performance. The new simulator outperforms previous learning based approaches on a single contact push manipulation prediction task. We also present results showing that the method works for multi-contact manipulation, for which rigid body simulators are notoriously unstable.
The paper presents a driver model identification method based on simulator experiments. The visual and vestibular perception of the driver can be modeled by measuring proper signals of the vehicle motion and the envir...
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The paper presents a driver model identification method based on simulator experiments. The visual and vestibular perception of the driver can be modeled by measuring proper signals of the vehicle motion and the environment during the real-time driving of the simulator. The parameters of different drivers are then estimated using a linear difference autoregressive model structure and least-squares estimation techniques. The aim of the identification is to describe the different driver behaviors with the parameters of a driver model with similar structure. The identified driver models are validated by simulation using the same excitation signals as in the simulator experiment and comparing the measured and simulated output of the driver. The main novelty of the paper is the identification method in which a real-time simulator is used.
In this paper, we consider the signal-anticipating behavior in local volt/var control in distribution systems. We define a voltage control game, and show that the signal-anticipating voltage control is the best respon...
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In this paper, we consider the signal-anticipating behavior in local volt/var control in distribution systems. We define a voltage control game, and show that the signal-anticipating voltage control is the best response algorithm of the voltage control game. We further show that the voltage control game has a unique Nash equilibrium, characterize it as the optimum of a global optimization problem, and establish its asymptotic global stability. We then introduce the notion of the price of signal-anticipating (PoSA) to characterize the impact of the signal-anticipating in local voltage control, and use the gap in cost between the network equilibrium in the signal-taking voltage control and the Nash equilibrium in the signal-anticipating voltage control as the metric for PoSA. We characterize how the PoSA scales with the size, topology, and heterogeneity of the power network for a few special cases. We find that the stronger the coupling between different buses is, the larger the PoSA is; the linear network gives the largest PoSA among all possible topologies, but as the size of the network increases, the PoSA will saturate.
Modern aircraft increasingly rely on electric power, resulting in high safety criticality and complexity in their electric power generation and distribution systems. Motivated by the resulting rapid increase in the co...
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This paper deals with the problem of designing an iterative learning control algorithm for discrete linear systems using repetitive process stability theory. The resulting design produces a stabilizing output feedback...
This paper deals with the problem of designing an iterative learning control algorithm for discrete linear systems using repetitive process stability theory. The resulting design produces a stabilizing output feedback controller in the time domain and a feedforward controller that guarantees monotonic convergence in the trial-to-trial domain. The results are also extended to limited frequency range design specification. New design procedure is introduced in terms of linear matrix inequality (LMI) representations, which guarantee the prescribed performances of ILC scheme. A simulation example is given to illustrate the theoretical developments.
Recently, researchers have discovered unexpected bumps in the detection rate curve of yet another steganographic scheme (YASS). We refer to this abnormal phenomenon as non-monotonic security performance. This paper fi...
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As a kind of flexible aircraft, the aerodynamic configuration of airship is maintained by superpressure of internal gas completely. And the pressure difference must be controlled in a safe range. Aiming at these issue...
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As a kind of flexible aircraft, the aerodynamic configuration of airship is maintained by superpressure of internal gas completely. And the pressure difference must be controlled in a safe range. Aiming at these issues, the models of pressure difference and solar radiation are built. Combining with the airship thermodynamic model, pressure control is achieved. A method of direct control is presented. According to the pressure value of atmosphere and the desired pressure difference, the internal pressure of airship that needs to be maintained can be figured out. And the change of internal gas can be obtained accordingly. Aiming at the hovering phase, the models and the control method are simulated. The control results of pressure difference and the thermodynamic properties are obtained, which illustrate the effectiveness of control method.
Industry regulations and standards are placing ever increasing limitations on the individual and total harmonic distortion levels that can be injected into the grid and hence an LCL circuit becomes an attractive optio...
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Industry regulations and standards are placing ever increasing limitations on the individual and total harmonic distortion levels that can be injected into the grid and hence an LCL circuit becomes an attractive option to interconnect an inverter to the utility grid. However, despite the benefits of LCL filter in reducing the switching harmonics, the inherent resonance present in this filter can cause a closed-loop stability problem due to increased grid current distortion. This paper develops a model predictive based current control for a three-phase grid connected converter with an LCL filter. The objective is to provide fast tracking response of the desired system reference coupled with suppression of the resonance disturbance caused by the LCL filter.
This work describes methodology for implementation of high-performance synthetic heat generators within the FPGA fabric. The proposed design flow is compatible with vendor tools and the generated synthetic heat genera...
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This work describes methodology for implementation of high-performance synthetic heat generators within the FPGA fabric. The proposed design flow is compatible with vendor tools and the generated synthetic heat generators can be seamlessly integrated with existing designs. Various architectures of synchronous and asynchronous heaters are evaluated in terms of their efficacy and dynamic range. We provide temperature and power measurements of the heaters implemented in Virtex5 FPGA. Measuring power consumption allows to validate heater performance and the extent to which its power dissipation can be controlled.
Augmented finite transition systems generalize nondeterministic transition systems with additional liveness conditions. We propose efficient algorithms for synthesizing control protocols for augmented finite transitio...
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