In the present work we are interested on the derivation of power-based passivity properties for a certain class of non-linear mechanical systems. While for general mechanical systems, it is of common use to adopt a st...
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ISBN:
(纸本)9783540738893
In the present work we are interested on the derivation of power-based passivity properties for a certain class of non-linear mechanical systems. While for general mechanical systems, it is of common use to adopt a storage function related to the system's energy in order to show passivity and stabilize the system on a desired equilibrium point(e.g., IDA-PBC [1]), we want here to obtain similar properties related to the system's power. The motivation arises from the idea that in some engineering applications (satellite orbit motion, aircraft dynamic,etc...)seems more sensible to copewith the power flowing into the system instead of the energy that, for stabilization purposes, means to consider the systems's equilibrium the state for which the energy flow-rate (i.e.,system's power)achieve its minimum. In this respect, we recall first the power-based description for a certain class of (non)-linear mechanical systems given in [2] and then we give sufficient conditions to obtain power-based passivity properties, provided a suitable choice of port-variables. We conclude with the example of the inverted pendulum on the cart.
This paper presents a method for recognizing the initial position of the weld in the global environment based on corner detection technology. Through the image preprocess that include the smoothing process, the sharpe...
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ISBN:
(纸本)9783540733737
This paper presents a method for recognizing the initial position of the weld in the global environment based on corner detection technology. Through the image preprocess that include the smoothing process, the sharpening process, the region segmentation and so on, the work pieces can be segmented from the background. Based on the preprocess image, the initial position of the weld seam can be detected by the Harris operator in global environment. The Harris operator is a kind of stable algorithm of corner detection. The operator is logical and symmetrical. The result shows that this method has the characters of anti-jamming, accuracy and fast computing.
Interconnection and damping assignment passivity-based control (IDAPBC) is a recently developed method for nonlinear controller design. A majority of the examples of IDA-PBC found in literature are from the electro-me...
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ISBN:
(纸本)9783540738893
Interconnection and damping assignment passivity-based control (IDAPBC) is a recently developed method for nonlinear controller design. A majority of the examples of IDA-PBC found in literature are from the electro-mechanical domain. To show its applicability in other domains, in this work IDA-PBC is used to design a stabilizing controller for a process control example, the four-tank system. Both simulations and real experiments are provided for this example system.
The torch orientation plays an important role in welding a lap joint. This paper proposes a torch orientation planning method for planar lap joint. In this method, the seam coordinates are firstly generated based on t...
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ISBN:
(纸本)9783540733737
The torch orientation plays an important role in welding a lap joint. This paper proposes a torch orientation planning method for planar lap joint. In this method, the seam coordinates are firstly generated based on the visual servoing approach. The rotation matrix describing the torch orientation is calculated at each seam point according to the geometrical contains of the torch, which is set according to welding conditions and the arrangement of the workpiece. The rotation angle increments used to adjust the torch orientation is then calculated. A curve seam was used to validate this method. The robot movement experiments prove the torch can be automatically adjusted to the desired orientation when the robot moves the torch along the seam using the generated seam coordinates.
This paper presents a general modeling method to construct a virtual Lagrangian for infinite-dimensional systems. If the system is self-adjoint in the sense of the Fretchet derivative, there exists some Lagrangian for...
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ISBN:
(纸本)9783540738893
This paper presents a general modeling method to construct a virtual Lagrangian for infinite-dimensional systems. If the system is self-adjoint in the sense of the Fretchet derivative, there exists some Lagrangian for a stationary condition of variational problems. A system having such a Lagrangian can be formulated as a field port-Lagrangian system by using a Stokes-Dirac structure on a variational complex. However, it is unknown whether any infinite-dimensional system can be expressed as an Euler-Lagrange equation. Then, we introduce a virtual Lagrangian with a homotopy operator. The virtual Lagrangian defines a self-adjoint subsystem, which is realized by a cancellation of non-self-adjoint error subsystems.
With the ongoing miniaturization in products, there is a growing demand for the development of accurate forming process for mechanical micro-parts. However, in microforming process, the size effects come up and make t...
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ISBN:
(纸本)9783540733737
With the ongoing miniaturization in products, there is a growing demand for the development of accurate forming process for mechanical micro-parts. However, in microforming process, the size effects come up and make the knowledge of the usual forming process can not be used directly. This paper investigates the size effect of H62 with the uniaxial tension experiments, and the results show both the grain size effect and the feature size effect. On the basis of the tension data, the LS-DYNA is used to analysis the micro-extrusion process. The simulation results show that the friction condition affect the microforming process seriously. When the friction condition changes, the stress state of the deformed material also changes. With the increasing of the friction coefficient, the extrusion force increases rapidly.
The stabilization problem of nonholonomic mobile robots that move on uneven surface is investigated. Smooth control laws ensuring practical stabilization are proposed based on the transverse function approach and the ...
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ISBN:
(纸本)9783540733737
The stabilization problem of nonholonomic mobile robots that move on uneven surface is investigated. Smooth control laws ensuring practical stabilization are proposed based on the transverse function approach and the integrator backstepping technique. Firstly, a transverse function which defines a smooth embedded submanifold is constructed, and an augmentation procedure is applied to the kinematic model of the robots. Then, the left-invariance property of the kinematic model is explored, and after the defining of the error variables via group operation, smooth exponential stabilizing control laws are derived for the error dynamic system, thus the kinematic model is rendered practically stable. Finally, the obtained control laws are utilized in the integrator backstepping process to stabilize the dynamic model. Simulations are provided to demonstrate the effectiveness of the algorithm.
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