A novel manipulator trajectory planning approach using geodesic is proposed in this paper. Geodesic is the necessary condition of the shortest length between two points on the Riemannian surface in which the covariant...
ISBN:
(纸本)9783540733737
A novel manipulator trajectory planning approach using geodesic is proposed in this paper. Geodesic is the necessary condition of the shortest length between two points on the Riemannian surface in which the covariant derivative of the geodesic's tangent vector is zero. The geometric characteristic of geodesic is discussed and used to implement trajectory planning of the manipulator. First, the Riemannian metric is constructed according to the planning task, e.g. to establish a distance metric by arc length of the trajectory to achieve shortest path. Once the Riemannian metric is obtained, the corresponding Riemannian surface is solely determined. Then the geodesic equations on this surface can be attained. For the given initial conditions of the trajectory, the geodesic equations can be solved and the results are the optimal trajectory of the manipulator in the joint space for the given metric. The planned trajectories in the joint space can also be mapped into the workspace. To demonstrate the effectiveness of the proposed approach, simulation experiments are conducted using some typical manipulators, e.g. spatial 3R, 3-PSS parallel and planar 3R manipulators.
Total Energy Shaping is a controller design methodology that achieves (asymptotic) stabilization of mechanical systems endowing the closed-loop system with a Lagrangian or Hamiltonian structure with a desired energy f...
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ISBN:
(纸本)9783540738893
Total Energy Shaping is a controller design methodology that achieves (asymptotic) stabilization of mechanical systems endowing the closed-loop system with a Lagrangian or Hamiltonian structure with a desired energy function-that qualifies as Lyapunov function for the desired equilibrium. The success of the method relies on the possibility of solving two PDEs which identify the kinetic and potential energy functions that can be assigned to the closed-loop. Particularly troublesome is the PDE associated to the kinetic energy which is nonlinear and non-hornogeneous and the solution, that A defines the desired inertia matrix, must be positive definite. In this paper we prove that we can eliminate or simplify the forcing term in this PDE modifying the target dynamics and introducing a change of coordinates in the original system. Furthermore, it is shown that, in the particular case of transformation to the Lagrangian coordinates, the possibility of simplifying the PDEs is determined by the interaction between the Coriolis and centrifugal forces and the actuation structure. The example of a pendulum on a cart is used to illustrate the results. Copyright (C) 2006 IFAC.
In this chapter we look at a geometric target assignment problem consisting of an equal number of mobile robotic agents and distinct target locations. Each agent has a fixed communication range, a maximum speed, and k...
ISBN:
(纸本)9783540735694
In this chapter we look at a geometric target assignment problem consisting of an equal number of mobile robotic agents and distinct target locations. Each agent has a fixed communication range, a maximum speed, and knowledge of every target's position. The problem is to devise a distributed algorithm that allows the agents to divide the target locations among themselves and, simultaneously, leads each agent to its unique target. We summarize two algorithms for this problem;one designed for "sparse" environments, in which communication between robots is sparse, and one for "dense" environments, where communication is more prevalent. We characterize the asymptotic performance of these algorithms as the number of agents increases and the environment grows to accommodate them.
Resistance spot welding quality is always one of key subject matters for study to which many welding scholars at home and abroad in the world devote *** has not been solved satisfactorily at present. The complexity of...
ISBN:
(纸本)9783540733737
Resistance spot welding quality is always one of key subject matters for study to which many welding scholars at home and abroad in the world devote *** has not been solved satisfactorily at present. The complexity of spot welding process, invisibleness of nugget formation and singleness of control method decide that stabilizing quality is a rather difficult task. The limitations of describing how the nugget grows up based on single-sensor information source is analyzed. A control method of multi-parameter comprehensive decision making for spot welding is put forward. The multi-sensor information fusion is adopted for real time monitoring four parameters which are closely concerned with the weld nugget size(welding current, electrode displacement, dynamic resistance, welding time). information fusion algorithm includes sensor-based weighted average fusion algorithm and knowledge-based production rule fusion algorithm. The spot welding experiments indicate that nugget size fluctuations are within 8%similar to 22% under constant current control, and are within 6%similar to 12.5% under information fusion control. It conforms that the new quality control method can compensate for various factors of influence in the welding process such as shunt, loop inductive reactance variation and electrode wear, etc, and assure the spot welding quality to be stable.
When applying autonomous industrial robotic systems in an unknown/partially known or cluttered environment, mapping and representation of the environment as well as collision detection becomes crucial. Existing techni...
ISBN:
(纸本)9783540733737
When applying autonomous industrial robotic systems in an unknown/partially known or cluttered environment, mapping and representation of the environment as well as collision detection becomes crucial. Existing techniques in these areas are generally complex and computationally expensive to implement. In this paper an efficient sphere representation method is introduced for environment representation, collision detection and distance queries. In particular, this method is designed for the application in an autonomous bridge maintenance system. Simulation results show that this method is effective in environment representation and collision detection. Furthermore, the proposed method is also computationally efficient for real-time implementation.
A novel control scheme is proposed for passive compass-like biped based on the concept of anti-phase synchronization. Under this framework, various interesting properties of the stable biped gait are studied. The dyna...
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ISBN:
(纸本)9783540733737
A novel control scheme is proposed for passive compass-like biped based on the concept of anti-phase synchronization. Under this framework, various interesting properties of the stable biped gait are studied. The dynamics of the biped is decoupled by inverse dynamic control and two legs of the biped are converted to be independent parallel subsystems. The coupled synchronization controller is designed which can effectively solve the anti-phase synchronization control problem. The proposed anti-phase synchronization control scheme can also make the mechanical energy of the robot reach a desired level while the average velocity tracking a target value. By designing a Lyapunov function, the stability and convergence of the anti-phase synchronization controller are proved. Simulation is conducted to show the effectiveness of the proposed control scheme. It is demonstrated that the proposed method is useful for analysis and design of the biped gait.
This paper explains the principle and method to calibrate the image plane center of the camera by use of laser in the pre-calibrate process of the intrinsic parameters of the visual sensor. The laser facula image has ...
ISBN:
(纸本)9783540733737
This paper explains the principle and method to calibrate the image plane center of the camera by use of laser in the pre-calibrate process of the intrinsic parameters of the visual sensor. The laser facula image has been disposed properly, so the accurate position has been located by calculating the center of mass. Consequently, the image plane center can be calibrated accurately. After the calibration, the guiding experiments show that the precision of the system is quite good which proves that camera calibrated by the method presented by this paper can satisfy the requirement of the whole system.
Arc welding is a complex phenomenon involving intensive interactions among heat, arc and arc force. To minimize the undesirable interference in weld pool imaging, a pulsed laser beam projects a strong illumination ont...
ISBN:
(纸本)9783540733737
Arc welding is a complex phenomenon involving intensive interactions among heat, arc and arc force. To minimize the undesirable interference in weld pool imaging, a pulsed laser beam projects a strong illumination onto the weld pool area. The ultra-high shutter speed vision system is synchronized to capture the weld pool image in the given short period. Through image processing, the geometrical information of the weld pool is obtained. It is input to a neurofuzzy logic controller so that the welding parameters like welding current and welding speed can be changed in real time to achieve desired weld dimension in response to the changes in welding conditions.
We consider hidden Markov processes in discrete time with a finite state space X and a general observation or read-out space gamma. The identification of the unknown dynamics is carried out by the conditional maximum-...
ISBN:
(纸本)9783540735694
We consider hidden Markov processes in discrete time with a finite state space X and a general observation or read-out space gamma. The identification of the unknown dynamics is carried out by the conditional maximum-likelihood method. The normalized log-likelihood function is shown to satisfy a uniform law of large numbers over certain compact subsets of the parameter space. Two cases are covered: first, when the running value of the transition probability matrix, denoted by Q is positive, second, when Q is primitive, but the read-out densities are strictly positive.
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