Search

In the actual operation by crane operator, there will appear situation that operator cannot make timely judgment on distance between crane and adjacent obstacle and cause collision accident. For this problem, this paper establishes anti-collision system on distance measurement focuses on ARM 11, on the basis based on machine vision and image procession, it considers effect of corresponding point match and extraction deviation of single characteristics point on measurement result, adopts one kind of method of distance measurement by monocular vision based on single characteristic point. The test result indicates that this system can effectively measure distance with obstacle, it has accurate measurement, high reliability and it can meet real-time requirement.

In this work, we examined the non Gauss distribution characteristic and evolution law of the wavelet coefficient of a gust using wavelet transform; according to the time-frequency characteristic, the wavelet transform coefficients and the energy relations of the target velocity spectra are derived; the wavelet coefficient is generated using the cascade model reflecting the turbulent intermittent; the unsteady gust artificial generation method is established based on inverse wavelet transform; and the arbitrary unsteady fluctuation law can be generated by regulating the coefficient of low frequency. The results show that: the natural gust is in good agreement with Karman wind speed spectrum, meets the turbulence-5 / 3 law in the inertial subrange, and exhibits the nature of intermittence and local self-similarity; the artificial wind sequence based on the inverse wavelet transform method shows similar turbulence statistics with natural gust, with which, the effectiveness of the method is confirmed.

The P-sets consists of an internal P-set and an outer P-set . It has dynamic characteristics. In order to obtain a new method of generation and identification information, the paper proposes the concepts of-recursive genetic information and-recursive genetic degree by using the dynamic characteristic of the internal P-set. Also the structure and characteristics about-recursive genetic information are given, including the the identification theorems and the identification criterions for the-recursive genetic information. Finally, the application example of the-recursive genetic information is provided. The structure of the-recursive genetic information is a new mathematical tool to process informaiton that has inward contraction characteristic.

EPS can improve many aspects including chassis coordinated control. Aimed at eliminating the adverse effects deriving from the controlled and uncontrollable differential braking condition, this paper analyzed the EPS-based compensation system control strategy. Coordinated control of EPS and differential braking ensures the vehicle driving safety and driving comfort purposes. Based on the above research, this paper verified the EPS compensation control strategy in simulation environment.

In order to provide effective power for small aerocraft, this paper offers a design of an electromagnetic vibration energy harvester based on MEMS technology, which works in special launching environment. According to "mass-spring-damper" system theory, this paper firstly built a model of the pick-up system, and discussed the pick-up system's response to sinusoidal input and impact load. Then, an energy conversion system was modeled, in order to analyze the system's power output. ANSYS simulation has been done on the pick-up system of different structures & parameters, and the relationship between different structures & parameters and the energy harvester voltage output has been studied. Based on the theoretical analysis and software simulation, the designed energy harvester working high frequency vibration environment can produce voltage over 200mV, which is enough for micro-sensor, low-power circuit in aerocraft.

To solve the key technology of automotive lithium battery charging system, a new kind of smart portable on-board charger is developed. This battery charger takes single-chip machine of freescale as system control chip, realizes closed-loop control of bus voltage by the voltage pulse width modulation chip TL494, realizes charger output with constant voltage, constant current and switch without disturbances by the current pulse width modulation chip UC3846, achieves master-slave control mode for multi–parallel machines through the CAN bus technology. In addition, the microcontroller program realizes the process monitoring and fuzzy PID regulation, the charging process has multiple intelligent protection and external regulatory functions. The experimental results show that with dual regulations of the software and hardware, the charger has the advantages of stable reliability, flexible operation and precise intelligence, an effective exploration of the battery charging technology is carried out.

In practical engineering design, torque is always ignored for the design of the crossing cantilever beams with equal spans, so that its safety reliability is reduced. Based on the theory of restraint moment, this paper deduces the simplified formula on the restrain moment generated among the crossing cantilever beams. At the same time, the application conditions of calculation formulae of the crossing cantilever beams with approximate equal spans are suggestively given. By the contrast analysis, the influence factors of torque are proposed in conception design and it is proved that the formula can be used in engineering design.

Computer-aided conceptual design of mechatronic products is becoming more and more important since it offers much convenience in design scheme retrieval and enhances the utilization of existing designs. One of the key technologies for computer-aided conceptual design is an efficient search algorithm for retrieving existing designs. As such, it’s necessary to find a feasible way to select the most suitable design out of a number of candidates for further development. By applying behavioral modeling method for representation of conceptual design, this paper proposes a node matching algorithm for searching behavioral model, together with a model similarity evaluation method. Based on these methods, a framework for computer-aided conceptual design is subsequently proposed. Finally, a case study is presented to illustrate the applicability of the proposed methodologies.

Effective simulation and analysis about wind turbine foundation simplified model experiment were conducted by using general finite element analysis (FEA) program ANSYS. Nonlinear finite element model with surface-to-surface contact pair was built to study the strain distribution of the steel interface and slip between steel and concrete. Relevant strain and spreading length curves under the load of every class were obtained. The numerical simulation results were in good agreement with the experimental results. And proper parameters of bond-slip relationship for steel and concrete in wind turbine foundation were confirmed. The finite element model established and analysis results can provide a theoretical reference for later research, and have significant value for optimal design of wind turbine foundation.

It is difficult to obtain exact solutions of the nonlinear partial differential equations (PDEs) due to the complexity and nonlinearity, especially for non-integrable systems. In this case, some reasonable approximations of real physics are considered, by means of the standard truncated expansion approach to solve real nonlinear system is proposed. In this paper, a simple standard truncated expansion approach with a quite universal pseudopotential is used for generalized fifth-order Korteweg-de Vries (KdV) equation, we can get two kinds of approximate solutions of the above equation, in some special cases, the approximate solutions may become exact. The same idea can also used to find approximate solutions of other well known nonlinear equations. We find a quite universal expansion approach which is valid for various nonlinear partial differential equations (PDEs).

Proceeding from the industrial design, this paper proposed the concept of product form gene with combining the product form and product style, and researched on the extraction of product form gene based on constraint style. It explained how to express product form gene based on style constraints, and construct the description model of product style semantic. This paper using analytic hierarchy process and semantic differential method to extract product gene, and take the real example to illustrate and validate, thereby providing a certain methodology direction for extraction of product form gene.

Design evaluation is necessary and important for conceptual design because it is often a must for designers to select a design concept from a number of candidates for further development. Assembly devices are usually product specific and there need extensive efforts in developing a feasible conceptual design solution satisfying a number of design constraints. To get a suitable evaluation method for assembly devices in the conceptual design phase, it’s necessary to apply Fuzzy mathematics in the evaluation method and the corresponding algorithm. This paper proposes a fuzzy index evaluation method for the conceptual design of assembly devices, where a number of evaluation indexes specific for assembly devices are proposed and organized into various levels for the evaluation algorithm. Finally, an evaluation software platform is presented, together with a simple design case study to illustrate the application of the proposed evaluation methodology.

In the structure design, the definition of the joints had a great impact on the structure internal force distribution, thus affecting the whole structure design. In the traditional design of steel structures, the beam-column joints were always considered as completely rigid connections or ideal hinged connections, but it is usually not in accord with the practical situations. According to the existing formulas, the simplified formulas for the end moments of semi-rigid connections have been proposed, the semi-rigid connections will also be discussed. The formulas proposed in this paper are applied to the auxiliary beam-column joint design, which is part of the counterforce frame design. It is hoped that the formulas can provide a reference for the steel frame design. Keywords: semi-rigid connections, end moments, internal forces distribution, steel frame design