Earticle

To improve the traditional welding methods that cannot meet the high-quality and efficient welding requirements of the corrugated sheets and other large work pieces, a visible and intelligent method to monitor the fillet welding of corrugated sheets and the equipment were researched. A system based on single laser line to track the assembly gap to be welded was developed and built. First, a system consisting of work-piece, torch, laser, and camera was assembled to monitor the fillet welding, and the coordinates for the motion platform, camera, and image were established. Then, according to the image of projection lines, a model was developed to analyze and calculate the change in width and position of the assembly gap caused by the undulating edge and deformation of the corrugated sheet and base plate. Finally, the work-piece was measured by contacting method and the result was compared with that obtained by automatic monitoring based on the visual sensors. The results indicated that the monitoring of width and trajectory of the assembly gap can reach an accuracy of ±0.5mm. This level of precision is sufficient for the requirements of controlling the torch and adjusting welding parameters in automatic welding of container corrugated sheet.

In this paper, the chaotic behaviors in the fractional order Chen system with time delays are numerically investigated. By use of the fractional calculus techniques, we find that chaos exists in the fractional order Chen system with time delays when the order is less than 3. Chaos synchronization of the fractional order Chen system is theoretically and numerically studied using active control. Through the analysis of the error dynamical systems by using the Laplace transform theory, the time-delay correlative synchronization controller is designed to achieve chaos synchronization. At last, numerical simulations are provided to verify the effectiveness and feasibility of the developed method.

In the process of high speed milling of titanium alloy, the milling temperature change had an adverse effect on machining accuracy, machining surface integrity and machining efficiency. To deal with this problem, heat conduction mode, the heat convection between cutting tools and air medium, and heat flux intensity boundary conditions in actual milling process are fully considered. And according to general heat equation, the heat conduction model of transient temperature field is built. The differential form of temperature field model are converted into corresponding form of the integral functional equation by the weighted residual method. A certain accuracy method for calculating the approximate solution is presented. And the transient temperature response of space element in milling system is obtained under equal time intervals. Finally it is proved that the model is correct by experiment result, which laid a solid foundation for accurately analyzing milling temperature.

After introducing digital HDTVs, smart consumers now require new DTV services. ATSC has adapted 3DTV standard which is ATSC SC-MMH (Service Compatible 3DTV using Main and Mobile Hybrid delivery), and the 3DTV standard uses the ATSC M/H transmission system. Even though an 8-VSB frame has only 0.8% training sequence, an ATSC M/H frame has about 3.9% training sequence when the number of group is 8. So the longer training sequence of ATSC M/H can be used to improve the performance of channel equalization technique. This paper uses LMS-based channel equalization techniques, and compares the equalization performance of ATSC M/H transmission system with ATSC 8-VSB system. By the benefit of longer training sequence of ATSC M/H, the equalizer works well in Ricean channel of K = 0 dB.

For the influence of time varying model parameters on servo accuracy of hydraulic quadruped robot joint torque, the equivalent model of electro-hydraulic force servo system was derived, the compound control strategy including flow compensator and velocity feed forward was proposed, the principle of compound control strategy was given. The flow of electro-hydraulic servo valve is linear with the input signal which realized by the flow compensator, the time varying parameters of inertia and elastic load were inhibited by velocity feed forward, and then the high accuracy joint torque control was realized. The composite strategy was verified on Co-simulation of MATLAB & AMESim platform, the simulation results show that the compound control strategy can effectively inhibit the parameter perturbation and the Amplitude attenuation of the tracking signal is less than 10% , and verify efficiency of the proposed control strategy.

Considering the fluctuating energy transfer between the SGS (Sub-Grid Scale, SGS) turbulent kinetic energy of gas and the second-order moment of particles, the gas-solid interaction model is present. The second-order term is studied, and the simulation results of second-order interaction are analyzed and compared with the simulation results by Koch. The effects of second-order interaction on concentration, velocity and second-order moment of particles and the SGS turbulent kinetic energy of gas are all researched.

The paper presents an intelligent remote control for heating system, which is capable of maintaining room temperature on a set value, using PID and optimizing algorithm. Heater node receives the set temperature by remote control and maintains a constant temperature by generating error signal from difference between set value and sensor value. Optimized values of KP, KI, KD are calculated by PID controller with optimizing algorithm and has been implemented on real time heater system which comprises dimmer, processing unit, RF modem and remote control consists of switch array, RF modem, LCD display and processing unit. To select optimizing algorithm comparative analysis has been done for GA and PSO. It is observed through experimental set, that as compared to conventional heater the energy saving with PSO-PID is more than PID and GA-PID to maintain a constant room temperature. It is concluded that PSO-PID shows better energy saving, when implemented on heating system.

The exact closed-form outage probability (OP) expressions of the multiple-mobile-relay-based mobile-to-mobile (M2M) cooperative networks over N-Nakagami fading channels are derived for selection incremental relaying (SIR). Then the OP performance under different conditions is evaluated through numerical simulations. The numerical simulation results coincide with the theoretical results well, and the accuracy of the analytical results is verified. The simulation results showed that: the fading coefficient, the number of cascaded components, the relative geometrical gain, and the power-allocation parameter have an important influence on the OP performance.

Sensor nodes in a WSN are deployed with the intention of collecting information such that the activities and environment in the target area can be faithfully reconstructed at a remote location using the raw data collected and action then may be taken based on same. Reliability of the deployed WSN becomes critical in this context as decision making could be adversely affected in case the reconstruction is incorrect. This becomes a major issue for Wireless Sensor & Actuator Networks where actuation is automated and solely dependent upon the reliability of information collected. The authors present a critical analysis of the various protocols and techniques proposed for ensuring reliability in Wireless Sensor Networks. A categorization of the techniques has been presented with emphasis on identifying the desirable features in a protocol which enables achieving higher degree of reliability. The challenges and critical requirements of reliable data acquisition as applicable to WSNs is also identified. The paper links the concept of reliability in WSNs to the traditional concept of reliability as applicable to devices.