In the paper an application of fuzzy neural networks (FNN) for sensor fault diagnosis in condensation turbine control unit was given. The FNN are applied for fault detection and isolation processes. This approach give...
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The paper discusses new developments of the data fusion paradigm due to Cortesao and Koeppe (1999, 2000). A bank of Kalman filters is analyzed in the fusion process. Experiments for a robotic compliant motion task (pe...
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The paper discusses new developments of the data fusion paradigm due to Cortesao and Koeppe (1999, 2000). A bank of Kalman filters is analyzed in the fusion process. Experiments for a robotic compliant motion task (peg-in-hole) emerged from human skills are reported. Stereo vision and pose sense are fused to execute the task. Feedforward artificial neural networks (ANNs) are trained to transfer human skills to robotic manipulators.
This paper proposes an improved differential inverse kinematics algorithm which works good for high speed motion control. The dynamic constraint as well as the kinematic constraint is utilized for the inverse kinemati...
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This paper proposes an improved differential inverse kinematics algorithm which works good for high speed motion control. The dynamic constraint as well as the kinematic constraint is utilized for the inverse kinematics. The singular perturbation method helps to reduce inverse kinematics to be solvable. The numerical and experimental results show the performance of the proposed method clearly.
This paper addresses one of standard problems in enveloping grasp analysis, the so-called contact force distribution. First, a subspace structure is analyzed using projection matrices into four subspaces of contact fo...
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This paper addresses one of standard problems in enveloping grasp analysis, the so-called contact force distribution. First, a subspace structure is analyzed using projection matrices into four subspaces of contact force space. Motivated by an example demonstrating that a careless definition of contact force subspaces leads to completely invalid result, we propose a proper set of projection matrices using a special weighted pseudo-inverse. Next, an example of statical ambiguity is provided in obtaining contact force distribution, which implies that contact forces can not be determined in light of statical viewpoint. To resolve such ambiguity, we propose the notion of dynamical balance. By presenting a tool for identification of dynamically balanced motions and forces, we can have a complete characterization of the force distribution for a general enveloping grasp system.
In redundant manipulator research community, the phenomenon called torque instability has not yet been completely characterized using unanimous agreement on its mechanism. This article shows that the behavior is indee...
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In redundant manipulator research community, the phenomenon called torque instability has not yet been completely characterized using unanimous agreement on its mechanism. This article shows that the behavior is indeed caused by incomplete compensation of null dynamics related with self-motion. This instability can be avoided by proper control with compensation of nonlinear null dynamics, and we propose a method to stabilize conventional redundancy resolution schemes extended to dynamic controls.
There have been many bilateral micro-teleoperation systems handling a small object. Historically, Lawrence (1991) proposed the transparency-optimized architecture and passivity theorem for stability analysis of bilate...
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There have been many bilateral micro-teleoperation systems handling a small object. Historically, Lawrence (1991) proposed the transparency-optimized architecture and passivity theorem for stability analysis of bilateral teleoperation. He claimed that unless the task(or environment) impedance contains a significant inertial behavior, passivity condition for transparency-optimized architecture can not be satisfied. To overcome this problem, we analyze and propose a method which can satisfy passivity condition for the micro-teleoperation system handling a small inertial object based on the structures originated by Lawrence and Hashtrudi-Zaad et al. (1999) and velocity-force scaling property of micro-teleoperation.
In this paper the workspace optimization of translational 3-UPU parallel platforms with prismatic and universal joint constraints is performed. The workspace is parameterized using two design parameters, which are the...
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In this paper the workspace optimization of translational 3-UPU parallel platforms with prismatic and universal joint constraints is performed. The workspace is parameterized using two design parameters, which are the prismatic joint stroke and the difference between the distances of the center to one of the corners of the triangular plate of the base and of the moving platform. For a large range of values for these design parameters the workspace of the corresponding 3-UPU platforms is calculated. This workspace is called the constrained workspace. For each design of the constrained workspace, three performance indices are calculated: 1) the workspace volume; 2) the average of the inverse of the condition number; and 3) a global condition index which is a combination of the other two performance indices. Plots of each performance index as a function of the two design parameters are generated and optimal values for these design parameters are determined. Finally, for the optimal design, it is shown that by introducing limits to the angles of the universal joints axis, the isotropy of the parallel platform is improved.
This paper proposes a PID-type composite controller for controlling flexible arms modeled by the singular perturbation approach, and investigates a tuning method based on the proposed controller structure. For the slo...
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This paper proposes a PID-type composite controller for controlling flexible arms modeled by the singular perturbation approach, and investigates a tuning method based on the proposed controller structure. For the slow sub-controller, a PD plus disturbance observer is used, which eventually takes on PID form, and for the fast sub-controller, modal feedback PID control is utilized. The effects of design parameters of the controller on the closed loop response are investigated. Through simulation and experiments, the adequacy and performance of the proposed method are verified.
An adaptive, nonmodel-based controller is proposed for the tracking control of a flexible cantilever beam with a translational base support. A piezoelectric (PZT) patch actuator is bonded on the top surface of the bea...
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An adaptive, nonmodel-based controller is proposed for the tracking control of a flexible cantilever beam with a translational base support. A piezoelectric (PZT) patch actuator is bonded on the top surface of the beam to apply a controlled moment for vibration suppression requirement. By selecting a Lyapunov function candidate based on a very simple energy relationship, an adaptive nonlinear feedback gain for the PZT input voltage and a simple PD controller for the moving base input force are designed to make the closed-loop system energy dissipative and hence stable. Due to the non model-based nature of the controller, some favorable features appear such as elimination of control spillovers, suppression of residual oscillations of the beam and simplicity of the control implementation. The feasibility of the controller is demonstrated using numerical simulations. Although the controller derivation is based on the original distributed partial differential model, a two-node finite element model is used for the numerical solution of the coupled PDE of the system.
The dynamic stability of a mobile manipulator using ZMP compensation is considered. A unified approach for the two subsystems is formulated using a redundant scheme. First, to conserve the dynamic stability of the sys...
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The dynamic stability of a mobile manipulator using ZMP compensation is considered. A unified approach for the two subsystems is formulated using a redundant scheme. First, to conserve the dynamic stability of the system, we define the performance index for the redundant system using the ZMP (zero moment point). This performance index represents the stability of the whole mobile manipulator system. Then, the redundancy resolution problem for optimizing the given performance index is solved using the null motion. Finally, the performance of this method is demonstrated by simulation study.
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