Abstract: In this paper, we investigated the forward kinematic problem of the 3-6 parallel robots (Stewart platform) via a symbolic computation tool called Dixon resultant. 3-6 parallel robot is a variation of the classic 6-6 Stewart platform. First we constructed the system equations of 3-6 parallel robots with a certain coordinate system, and then gave the necessary and sufficient condition for the existence of roots of this system by resultant. With the expression of resultant, we could find the solution of the original system and determined the position of mobile platform. We also discussed how to deal with the extraneous roots.
Abstract: In order to convenient the design of the autocollimator interface, this paper introduces the design of hardware and software of the autocollimator interface, and detailed analysis some key links. The SPI extension module (EEPROM) based on abundance on-chip resource of TMS320F2812 DSP is used to storage the equivalent of misalignment angle; The CAN extension module (CAN bus) based on CAN module is used to communicate with other computers; SCI extension module (RS232) is used which is convenient for the system debugging, and extension interfaces are left. Meanwhile, the corresponding design of software is also given in the paper. Prototype tests show that the design of the autocollimator interface can fully satisfy the requirements of the system. The design experience can be referred in similar engineering.
Abstract: Flight simulation is a simulation of flight and various aspects of the flight environment. Flight simulation is used for a variety of reasons, including aircraft development and flight training. The engineering flight simulator is used for a certain commercial transport aircraft development. The aircraft adopts fly-by-wire flight control technology. The engineering flight simulator was mainly used as a platform to test flying quality of the aircraft. The simulator has actual aircraft cockpit with wide-field visual system mounted on large six degree of freedom(DOF) motion platform that feature comprehensive flight and systems models. In order to demonstrate the flying quality of the aircraft, Flying quality verification experiments were carried out on the simulator. This test provided a means by which one may evaluate flight characteristics for fly-by-wire flight control commercial transport aircraft. Experiment results were evaluated .
Abstract: The power plant boiler automatic control system is designed on the basis of Siemens S7-200 in this paper. Based on the introduction of the Siemens S7-200 and the works of the boiler, the total power plant boiler control system is designed in details. Besides the initialized program is designed based on the input and output address of all the switches. The communication program is achieved, including the initialization of the program running parameters, the call of the system subroutine, the calculation of the checksum, the real-time data receiving process, etc. Finally, the heat energy is successfully and automaticly converted to the electricity in the boiler based on the PLC.
Abstract: Grounded on Labview platform, the grid of technology of solution pH value contributes to a new device----the auto-control technology of solution pH value. This device is easier to operate just by the parameter input in the interface. And it breaks the limit of single admeasuring apparatus, meanwhile adopts the method of picking the average value by multi-metering, which avoids the delay effect caused by solution mixing link. The Acid precipitation-Flocculation process in paper making sewage sets an example for the pH value auto-control and supports PAC control of pH value with software concept.
Abstract: The structure and its function about a dual-axis rate turntable has been elaborated, its principle block diagram of control system is given. And its electromechanical system’s transfer function of the dual-axis rate table has been calculated and simplified reasonably based on experiments and practical situation, then a double loop control system constituted with a speed loop and a stabilization loop is got. Its’ correction link of the stabilization loop is calculated, which has a 2-order open loop transfer function. In order to achieve a suitable stability margin, the corresponding digital controller is designed, and its’ pulse transfer function response and the three-step iterative simulation results to a same sinusoidal excitation are got and compared, the same results verified the correctness of the design to the correction link.
Abstract: Based on the theory of elastodynamics , the relationship between the amplitude of crack reversed echo and the size of crack which detection by the T(0,1) modal is studied by the method of simulation. Based on the simulation result, T(0,1) modal sensitive to a radial crack which length below the perimeter of pipe and the reflection ratio increase as the length of crack raised are got. The T(0,1) modal is insensitivity to a permeate axial crack which length between 20% to 45% of wavelength. The reflectance became minimum when the length arrive at 50% of wavelength, it get maximum when size reach 90% of wavelength, then it has a small decrease till 100%.
Abstract: In order to simplify the traditional methods for simulating aircraft performance in ATC, a method is proposed in this paper by the flight aerodynamics theories, normal and maximal climb rate in steady climb motion and acceleration/deceleration of Straight-and-Level Flight of performance computation. This method can be used to simulate acceleration, deceleration, and climb/descent rate of usual civil aircraft types. It is convenient and useable compared with the traditional complex methods which need input many parameters manually in air traffic control (ATC) simulation. The experimental result listed in this paper coincides with the basic flying rules of aircraft types such as 737-300, A310-300, B747F, Y-7. The application of this method in the real ATC simulator for controller training proved its function and effect.
Abstract: The principle of holes leaking create ultrasonic and the relationship between the sound pressure and the pressure or hole size was discussed in this paper. A method of leak hole estimation by the relationship and a design of gas leak ultrasonic testing system were presented. Experimental results which obtained by the gas leak ultrasonic testing system indicated the method is stable, reliable and tallying with the actual results. The method can estimate the leak hole quickly and exactly. Compared with the method of fitting the Reynolds number and amount of leakage, the accuracy has improved to some extent, and it has certain significance in the fast detection of the leak hole size. It could be popularized in the gas leak ultrasonic testing system.
Abstract: Based on finite element analysis and explicit Euler method, the present study visualized the dynamical simulation of a knotless netting in R environment. In the physical models, the linking between knot and twine were considered as a mass-spring system. Vector algebra methods were applied to analyze the hydrodynamic forces and tensile forces of the spring. To solve the equations numerically, explicit Euler method was introduced for the mechanical system to achieve the stable solutions. A package of scatterplot3d in R program was transferred to realize the visualization of the knotless netting in three-dimensional space. The results of dynamical simulation were displayed distinctly to show the sinking processes and equibibrium state of the knotless netting in the sea water.