Applied Mechanics and Materials Vols. 80-81

Abstract: Friction property plays an important role in the operating process of engine, the analysis and discuss about friction property can help to improve the operating performance of engine. Based on the basic structure of swash-plate engine, the sphere rolling friction model and the roller rolling friction model were established, and corresponding formulae of the rolling friction force and the rolling friction coefficient were deduced. Then as an application, we employed the exact parameters of a swash-plate engine to calculate the sphere rolling friction force, the sphere rolling friction coefficient, the roller rolling friction force and the roller rolling friction coefficient. According to comparison, we concluded that roller rolling friction force was far less than sphere rolling friction force, and roller rolling friction coefficient was far less than sphere rolling friction coefficient. Furthermore, we proposed two topics which would be our next study concerning engine friction property: friction-induced heat, and high temperature influence on friction property.

Abstract: Based on the analysis of two kinds of torsion absorber of automobile power train, a power train idling vibration model with nine degrees of freedom is established, the generalized Jacobin algorithms and the compiled Matlab procedures are used to calculate the idling natural frequency and idling natural vibration model. The results show that the dual mass flywheel torsion absorber can keep the power train from idling resonance compared with the clutch torsion absorber and play a good role in attenuating the low frequency torsion vibration of power train.

Abstract: High output power can be obtained by optimizing the piezoelectric battery structure parameters. Several piezoelectric battery prototypes with dimensions around 30mm×8mm×1mm have been set up to test the power from ambient vibration harvesting. Output power generation of 130 µW at 93.2 Hz is obtained for a typical device with cantilever beam width 8mm. The test results are consistent with the theory analysis and indicate that a piezoelectric battery for ambient vibration energy harvesting is a promising electric power source for wireless sensors nodes with micro-power consumption.

Abstract: Based on the description of 20MN fast forging press hydraulic system, the paper analyzed the possibility of energy conservation which the accumulator made in the fast forging machine system. When accumulator was used in fast forging machine, then analyzed the calculation results, and the energy conservation program of fast forging machine energy accumulator was evaluated briefly. The test system was set up on 20MN fast forging machine, and the paper researched the application of accumulator in fast forging press hydraulic system on absorbing hydraulic shock and eliminating pressure pulsation.

Abstract: The detection and diagnosis of equipment failures are of great practical significance and paramount importance in the sense that an early detection of these faults may help to avoid performance degradation and major damage. In this work, a novel methodology based on improved Hilbert-Huang transform (HHT) and support vector machine (SVM) was proposed for incipient bearing fault diagnosis with insufficient training data. Singular value decomposition (SVD) was employed to detect periodic features, and then extending of the original signal was carried out based on support vector regression (SVR). A screening process was conducted to select the vital intrinsic mode functions (IMFs). Finally, features extracted from the obtained IMFs were applied to identify different bearing faults based on SVM. To investigate the property of proposed method, an experimental test rig was designed such that varying sizes defects of a test bearing could be seeded, and it’s concluded that the effectiveness of the proposed algorithm in early bearing fault diagnosis even with insufficient training data.

Abstract: Considering high sensitivity of the walking gait of the biped passive dynamic robot to its own parameters, the paper obtains a more simple and efficient restraint strategy by analyzing the restraint of the ankle-angle to the period doubling bifurcation and chaos, based on the model of humanoid forward-offset round feet. The forward offset round feet model is used to construct the dynamic equation of the passive walking and the numerical solution is for the final state of the model; while the robot’s own parameters are fixed and the slope is increased step by step, the gait features in terms of different phases of the angle are simulated and analyzed; then the self-adjustment of the gait shows that the restraint to the period doubling bifurcation or the chaos gait can be performed only by the adjustment of the ankle-angle. The result shows the superiority of our research on some aspects: the restraint to the period doubling bifurcation or the chaos gait, the reveal of the passive dynamic walking mechanism that parameters restrict each other, and the design of the control strategies in more complicated environment.

Abstract: The possibility of oxyhydrogen energy, which use real-time generated Hydrogen and Oxygen as its source, was analyzed. A special torpedo thermal power system, which uses oxyhydrogen energy, was put forward. The key technology to realize the system was discussed. The problems which the Open-cycle torpedo thermal power system encounters was solved by the closed-cycle technology, such as exhaust noise, flight path, the working efficiency of engine was influenced by the intensity of pressure of seawater.

Abstract: A mobile grinding robot is present here for the wind turbine blade grinding work. The robot is a mobile manipulator equipped with a grinding wheel. A mobile manipulator robot is built up with a mobile platform and a robotic arm mounted on it. The dynamic model of the robot is built, and the dynamic model of the two subsystems is derived from it, so the dynamic coupling items can be deduced. In order to discover how the coupling force influence the robotic manipulator, the SimMechanics model of the robot is built up and the simulation research is carried out by the built model. The results show the influence of coupling force on the manipulator.

Abstract: The paper introduces an electro-controlled steering damper’s working principle, which uses the magnetorheological fluid as the working medium, and derives the damper’s controlling and calculating method. The steering wheel’s return control strategies of it are investigated. In order to compare the control effect of the PD controller with the fuzzy controller, a simulation model of the vehicle’s steering system is established on MATLAB/SIMULINK. Then simulate the returning process of the front wheels at medium and high vehicle speed. The results show that the vehicle’s steering system equipped with the electro-controlled damper can restrain effectively the returning overshoot of front wheels when the steering wheel is returning automatically, and the effect of the fuzzy controller is excelled the PD controller, but it demands much more to the hardware for its larger calculation amount.

Abstract: This paper is based on using fuzzy control method and according to the size of bearing residual magnetic detective distance and the diameter of bearing ring; it accurately controls the size of demagnetization machine alternating current. The result shows that the fuzzy control method on bearing residual magnetic quality control by simulation can get a rational control effect of the size of demagnetization machine current. It provides a new theoretical method for precisely controlling the residual magnetic bearings quality.