Current Issue : July - September Volume : 2014 Issue Number : 3 Articles : 7 Articles
This paper focuses on high precision leveling control of an underwater heavy load platform, which is viewed as an underwater\nparallel robot on the basis of its work pattern.The kinematic of platform with deformation is analyzed and the dynamics model\nof joint space is established. An adaptive backstepping controller according to Lyapunovââ?¬â?¢s function is proposed for leveling control\nof platform based on joint space. Furthermore, the ââ?¬Å?lowest point fixed angle errorââ?¬Â leveling scheme called ââ?¬Å?chaseââ?¬Â is chosen for\nleveling control of platform.The digital simulation and practical experiment of single joint space actuator are carried out, and the\nresults show high precision servo control of joint space. On the basis of this, the platform leveling control simulation relies on\nthe hardware-in-loop system. The results indicate that the proposed controller can effectively restrain the influence from system\nparameter uncertainties and external disturbance to realize high precision leveling control of the underwater platform....
An adaptive robust quadratic stabilization tracking controller with hybrid scheme is proposed for robotic system with uncertainties\r\nand external disturbances. The hybrid scheme combines computed torque controller (CTC) with an adaptive robust compensator,\r\nin which variable structure control (VSC) and H8 optimal control approaches are adopted. The uncertain robot manipulator is\r\nmainly controlled by CTC, the VSC is used to eliminate the effect of the uncertainties and ensure global stability, andH8 approach\r\nis designed to achieve a certain tracking performance of closed-loop system. A quadratic stability approach, which allows separate\r\ntreatment of parametric uncertainties, is used to reduce the conservatism of the conventional robust control approach. It can be also\r\nguaranteed that all signals in closed-loop system are bounded.The validity of the proposed control scheme is shown by computer\r\nsimulation of a two-link robotic manipulator....
Reinforcement learning algorithm for multirobot will become very slow when the number of robots is increasing resulting in an\nexponential increase of state space. A sequential Q-learning based on knowledge sharing is presented.The rule repository of robots\nbehaviors is firstly initialized in the process of reinforcement learning.Mobile robots obtain present environmental state by sensors.\nThen the state will be matched to determine if the relevant behavior rule has been stored in the database. If the rule is present, an\naction will be chosen in accordance with the knowledge and the rules, and the matching weight will be refined. Otherwise the new\nrule will be appended to the database. The robots learn according to a given sequence and share the behavior database.We examine\nthe algorithm by multirobot following-surrounding behavior, and find that the improved algorithm can effectively accelerate the\nconvergence speed....
This paper is an effort to enable the delta PLC (programmable logic controller) DVP14SS to communicate with the visual Basic 6.0 using modbus DLL. The communication between DVP14SS and visual basic 6.0 is via modbus serial protocol stated by delta PLC manufactures. In automated systems there are control supervision and also health and safety monitoring via supervisory control and data acquisition (SCADA) systems. Values of important parameters such as temperatures, pressures, voltages, etc are sensed and transferred to monitoring stations in control rooms. After processing the information, decisions are made and supervisory commands are sent to change conditions such as set points or to engage emergency procedures. The data from sensors and set commands to actuators are sent via wired or wireless communication channels. So, communication mechanisms are an integral part of any complex automated system. The SCADA software’s are the software packages and are not free and the cost depends on tag count. Visual basic 6.0 platform can be used to develop the SCADA application effectively. Using VB 6.0 a platform can be developed to integrate software and hardware across spectrum of vendors. Here, a simple approach is proposed; which takes care of the communication between delta PLC and visual basic using modbus DLL (provided by delta PLC). Visual basic can serve as a cost effective solution since it is not necessary to purchase a licenses for a small scale application as well as it is cheaper than conventional SCADA packages....
Theproblem of stability analysis for a class of networked control systems (NCSs) with network-induced delay and packet dropout is\ninvestigated in this paper. Based on the workingmechanism of zero-order holder, the closed-loop NCS ismodeled as a continuoustime\nlinear system with input delay. By introducing a novel Lyapunov-Krasovskii functional which splits both the lower and upper\nbounds of the delay into two subintervals, respectively, and utilizes reciprocally convex combination technique, a new stability\ncriterion is derived in terms of linear matrix inequalities. Compared with previous results in the literature, the obtained stability\ncriterion is less conservative. Numerical examples demonstrate the validity and feasibility of the proposed method...
Polyclonal based artificial immune network (PC-AIN) is utilized formobile robot path planning. Artificial immune network (AIN)\nhas been widely used in optimizing the navigation path with the strong searching ability and learning ability. However, artificial\nimmune network exists as a problem of immature convergence which some or all individuals tend to the same extreme value in\nthe solution space. Thus, polyclonal-based artificial immune network algorithm is proposed to solve the problem of immature\nconvergence in complex unknown static environment. Immunity polyclonal algorithm (IPCA) increases the diversity of antibodies\nwhich tend to the same extreme value and finally selects the antibody with highest concentration.Meanwhile, immunity polyclonal\nalgorithm effectively solves the problem of local minima caused by artificial potential field during the structure of parameter in\nartificial immune network. Extensive experiments show that the proposed method not only solves immature convergence problem\nof artificial immune network but also overcomes local minima problem of artificial potential field. So, mobile robot can avoid\nobstacles, escape traps, and reach the goal with optimum path and faster convergence speed....
A pinning stabilization problem of complex networks with time-delay coupling is studied under stochastic noisy circumstances in\nthis paper. Only one controller is used to stabilize the network to the equilibrium point when the network is connected and the\nminimal number of controllers is used when the network is unconnected, where the structure of complex network is fully used.\nSome criteria are achieved to control the complex network under stochastic noise in the form of linear matrix inequalities. Several\nexamples are given to show the validity of the proposed control criteria....
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