Advanced Materials Research Vols. 655-657

Abstract: A double-chamber PZT micropump with two PZT actuators and three cantilever valves is introduced. When the PZT actuators work in anti-phase, the output performance of the pump is equal to that of two one-chamber pump running in series. Besides, the pump performance depends on the characteristic and geometrical parameters of the PZT actuators. A prototype double-chamber serial micropump is fabricated with the PZT membrane of 0.2mm in thick and 15mm in diameter. The pump was tested with water as the working medium. The testing results show that both the flowrate and backpressure of the micropump with two chambers running are about 1.54 and 1.8 times those with one chamber running, respectively. With two chamber running, the achieved maximum flowrate is up to 3.85ml/min at 50V and 150Hz, and the maximum backpressure is about 34.2kPa at 50V and 180Hz.

Abstract: For the traditional sensorless vector control systems of permanent magnet synchronous motor, a new sensorless vector control method is proposed based on the power factor control. On the basis of analysis of the mathematical models for the permanent magnet synchronous motor, established a power factor voltage reference frame system. The rotor position and speed is estimated by the control of power factor angle, and then from the point of view of efficiency drive to configure the stator current. This stator current is arranged in the vicinity of the current minimum trajectory. This method not only can control the speed, but also ensure high power factor and high drive efficiency of the permanent magnet synchronous motor. The simulation results proved the effectiveness and feasibility of this control method.

Abstract: This paper introduces a new type of shock absorber: hydraulic electromagnetic energy-regenerative shock absorber (HESA), which can simultaneously implement the function of damping vibration and regenerating a portion of dissipated energies generated from passing through the damping hole. A test bench was trial-produced and used to prove the feasibility of the energy-regenerative scheme. The situation that hydraulic motor rotational speed has a sudden change in the energy regenerating process is theoretically analyzed.

Abstract: Electro-hydraulic proportional variable displacement piston pump is widely used in various fields because of energy-saving, low noise and advanced control technology. In this study, a fuzzy logic controller was used in a flow and pressure integrated controlled electro-hydraulic proportional variable displacement piston pump’s control system. The simulation model of variable displacement pump was built based on AMESim, and the model of control system with fuzzy logic controlled was built in Simulink. This study research the characteristics of electro-hydraulic proportional variable displacement piston pump’s control system through co-simulation.

Abstract: Although the chord height error might be ensured, the adaptive algorithm of the NURBS curve circular interpolation feed rate is still likely to result in the speed fluctuation which is not in accordance with given acceleration or deceleration rules. On the foundation of the analytic principle of the NURBS curve circular interpolation, a kind of interpolating algorithm based on the NURBS curve continuous small segments of S-shaped acceleration and deceleration is presented. And considering the chord height error, the variable step and feed rate can be effectively combined to make a better estimation. The simulation results on real examples show that the method not only simplifies the complicated calculation of curve interpolation process, simultaneously improves the speed of Motion Smoothing Implementation for NURBS curve interpolation, but also ensures the interpolation precision. The algorithm can be commonly applied in real manufacturing for high-speed and high-precision curve process.

Abstract: A/C axes bi-rotary milling head is an important functional component in gantry type five-axis CNC machine tool. The static characteristics affect directly the machining accuracy of machine tool. The paper investigates the static stiffness of A/C axes bi-rotary milling head in gantry type five-axis CNC machine tool XK2320-5X developed by a domestic company. Because this product developed depend on the experience of designers, the machining accuracy of A/C axes bi-rotary milling head of primitive XK2320-5X type cannot meet the accuracy requirement under actual working conditions. On the basis of structure design, the static stiffness analysis of the milling head under two working conditions is carried out using finite element method. The deformations of the main mechanical parts in the milling head are obtained. The analysis results indicate that the static stiffness in direction X is the weakest of the milling head and the milling head shell is the most important factor of deformation. The work done provides foundation for further structure design and machining accuracy improvement of A/C axes bi-rotary milling head.

Abstract: In high speed machining, excessive vibration and shock growing out of acceleration and jerk should be suppressed. Therefore, based on before acceleration/deceleration with linear jerk, a new NURBS curve interpolation was proposed. Interpolation feed and acceleration were planned employing before acceleration/deceleration with linear jerk evolution. During real-time interpolation, the interpolation feed and acceleration were calculated with polynomial fitting method, and with the second-order Taylor expansion, the interpolation parameter was computed. A NURBS curve was interpolated with the proposed method and the one with S curve acceleration/deceleration as comparison. The results indicated the proposed method not only maintain high feed but also reduce the interpolation output acceleration and jerk significantly, and its output jerk evolves along with time linearly. The proposed method can be used to reduce the vibration and shock from the high speed moving parts and improve their smoothness.

Abstract: According to the requirements of optimization for honing efficiency ,Through Matlab simulation and finite element analysis, this paper studied the influence factors of reticulate pattern quality and honing efficiency. These factors contain honing speed, reversing acceleration, oil-stone. This paper provides certain theoretical basis for reasonable selection of key technological parameters in high efficiency honing process .

Abstract: A general universal vertical lathe was studied in this paper which comprises two columns. The lathe can be used for roughing the cylindrical workpiece, end surface of inner hole and the inner and outer cone etc. The lathe structure and hydraulic system were improved on the basis of keeping the basic operating functions. After improvement of the lathe structure, it is more convenient for finding the exact position of the workpiece and the loading capability was improved. Meanwhile, the spindle can work smoothly and precisely. According to the improvement of the hydraulic system of the machine, the level of automation was enhanced and the working ability of the lathe was improved.

Abstract: Three solutions to network CNC machines are introduced. Advantages and disadvantages are compared. Wireless network solution supports a wider range of CNC communications but easy be disturbed. Single port server solution ensure stable signal but hardware cost is high. TCP/IP solution is stable and reliability while most low-end CNCs do not have Ethernet ports. CNC quantity, port type, distance between CNCs and computers, required speed and cost should be considered to choose right solutions.