The problem of controllability and control strategy for a class of networkedcontrolsystems (NCSs) with packets loss are studied in this paper. A probabilistic controllability conception is proposed for these systems...
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The problem of controllability and control strategy for a class of networkedcontrolsystems (NCSs) with packets loss are studied in this paper. A probabilistic controllability conception is proposed for these systems. In order to analyze the probabilistic controllability and relevant properties, a representation of the initial state by a group of constructive base of linear space is introduced. Based on this representation the affects to control system caused by packets loss can be expressed by system substates. A control strategy is developed to guarantee, the controllability of NCSs, and the minimum control steps property of this control strategy is discussed as well. Finally, a necessary and sufficient condition of probabilistic controllability for NCSs with packets loss is represented.
This paper investigates the optimal feet forces distribution and control of quadruped robots under external disturbance forces. First, we formulate a constrained dynamic model of quadruped robots and derive a reduced ...
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This paper investigates the optimal feet forces distribution and control of quadruped robots under external disturbance forces. First, we formulate a constrained dynamic model of quadruped robots and derive a reduced order dynamical model of motion/force. Consider an external wrench on quadruped robots, the distribution of required forces and moments on the supporting legs of a quadruped robot is handled as a tip-point force distribution and used to equilibrate the external wrench. Then, a gradient neural network is adopted to minimize the optimized objective function with linear equality and inequality constraints, and hybrid motion/force control based on adaptive neural network is used to compensate for the external perturbation in the environment and approximate feedforward force and impedance of the leg joints on line. The verification of the proposed control is conducted using the extensive simulations.
The most challenging difficulties for teleoperation systems are well recognized as the Internet uncertain time delays, which might degrade system performance or even lead to system instability. This paper proposes a n...
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The most challenging difficulties for teleoperation systems are well recognized as the Internet uncertain time delays, which might degrade system performance or even lead to system instability. This paper proposes a novel control framework for Internet-based teleoperation systems which is based on the prediction of jitter of Internet one-way time-delay. Internet jitter is predicated based on the sparse multivariate linear regression method. The slave system can be controlled using a virtual system provided at the master site, which is updated according to historical commands transmitted to the slave site and Internet jitter prediction results. The presented control framework is deployed in a virtual inverted pendulum teleoperation system developed. In the experiments, users successfully stabilize the remote virtual pendulum through the Internet, which demonstrate the effectiveness and prospect of the proposed Internet control framework.
This paper presents a collision-free path planning approach based on Bezier curve for a mobile manipulator with the endpoints restricted by the manipulator. Based on these candidate endpoints and the initial posture o...
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ISBN:
(纸本)9781479927456
This paper presents a collision-free path planning approach based on Bezier curve for a mobile manipulator with the endpoints restricted by the manipulator. Based on these candidate endpoints and the initial posture of mobile manipulator, a series of feasible Bezier paths are obtained with the constraints from velocity, acceleration and environment. And then the optimal collision-free path is determined according to the related information of the path as well as obstacles. The mobile manipulator has the ability to adapt to the environment and the optimal path will be updated once the new detected obstacles block this path. The path planning approach is verified by simulations.
A bi-branchiate robot is presented for the inspection of the high-voltage power transmission lines. With a symmetrical mechanical structure, the robot can roll along the power lines and negotiating all the obstacles i...
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A bi-branchiate robot is presented for the inspection of the high-voltage power transmission lines. With a symmetrical mechanical structure, the robot can roll along the power lines and negotiating all the obstacles in the lines to complete the inspection work. A hierarchical structure based on modular approach are used to design the control system of the robot. A combination mode composed of teleoperation via RF module and local intelligence based on visual servoing is developed to control the inspection robot. Using an image feature acquisition method based on Otsu adaptive threshold, the position and width of the power line in image plane are extracted as the basis of controller design. Experiments of obstacle negotiation and automatic line grasping in laboratory prove the effectiveness of the proposed robot prototype and the relative control method.
Generally, surgeons of minimally invasive surgery should possess good ability to coordinate their both hands. The manipulation of guide wire is considered a core skill. Obtaining that core skill to perform minimally i...
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ISBN:
(纸本)9781479927456
Generally, surgeons of minimally invasive surgery should possess good ability to coordinate their both hands. The manipulation of guide wire is considered a core skill. Obtaining that core skill to perform minimally invasive surgery requires training. In minimally invasive surgery, a surgical robot can assist doctors to position precisely and provide stable operation platform. Therefore, to develop a virtual reality simulators for training purpose based on a robotic guide wire operating system is an important and challenging subject. In this paper, a multi-body mass-spring model for simulating guide wire is presented and evaluated. In order to overcome the disadvantage of using mass-spring approach to model the guide wire, we propose a new collision detection algorithm and a new collision response algorithm. Finally, we test our guide wire with a complex and realistic 3D vascular model, which is selected from computer tomography database of real patients. The result shows that the virtual reality training simulators is effective and promising.
A general vision approach for environment understanding of mobile robot is proposed, which is inspired by biological visual cortex. Gray level image from robot camera is firstly processed in the selective attention la...
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ISBN:
(纸本)9781479927456
A general vision approach for environment understanding of mobile robot is proposed, which is inspired by biological visual cortex. Gray level image from robot camera is firstly processed in the selective attention layer, and then in S and C layers for meaningful structure elements. With the help of the Sc layer designed for endpoints detection, the line segments map is generated to serve as the form of environment understanding results. Experiments on mobile robot are implemented by the task of avoiding obstacles with different sizes and shapes, pits, sharp cliffs, et al. The experimental results demonstrate the adaptability and versatility of the proposed approach.
The large-scale assembly and fabrication method for single-walled carbon nanotube(SWCNT) nano devices was *** of SWCNT field effect transistor(FET) was realized by floating potential dielectrophoresis *** simulation o...
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The large-scale assembly and fabrication method for single-walled carbon nanotube(SWCNT) nano devices was *** of SWCNT field effect transistor(FET) was realized by floating potential dielectrophoresis *** simulation of floating potential distribution of the chip was performed by comsol multiphysics coupling *** hundred devices were assembled on the area of less than one square *** fabricated devices were characterized by atomic force microscopy and scanning electron *** experimental results showed that large-scale assembly had been realized,and the success rate of ideal assembly for SWCNT FET had been assessed.
Visual servo stabilization of nonholonomic mobile robots has gained extensive attention. However, currently, the solution of the problem does not consider both the visibility constraints and the actuator limitations, ...
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Visual servo stabilization of nonholonomic mobile robots has gained extensive attention. However, currently, the solution of the problem does not consider both the visibility constraints and the actuator limitations, so the designed controller is difficult to realize satisfactory performance in practical application. In this paper, a predictive controller for the visual servo stabilization of a mobile robot is presented. Firstly, a kinematic predictive stabilization controller utilized to generate the command of velocity is introduced. Then, in order to make the actual velocity of the mobile robot asymptotically approach to the desired one, a dynamic predictive controller is designed. The proposed predictive controller can deal with the constraints easily. Finally, several simulations are performed, and the results illustrate that the proposed control scheme is effective to solve the visual servo stabilization problem.
This article describes the control algorithm and software implementation of astronomical tracking based on the mechanical analysis for Five-hundred-meter Aperture Spherical Telescope(FAST) that is being built in Guizh...
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This article describes the control algorithm and software implementation of astronomical tracking based on the mechanical analysis for Five-hundred-meter Aperture Spherical Telescope(FAST) that is being built in Guizhou province of China, which aims to help astronomers resolve questions in cosmology. On the basis of position and attitude feedback algorithm of cable driven parallel robot, the control of X-Y positioner with feed-forward was introduced and the astronomical tracking experiments were conducted on scale model to verify the validity of control strategy. The future works for focus cabin suspension of FAST are also pointed out.
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