Advanced Materials Research Vols. 542-543

Abstract: The two-stage camera calibration is introduced firstly, and then the improvement on it is given. Through the nonlinear optimization of the results obtained by two-stage camera calibration, the pre-calibration of the image plane center of the CCD camera can be omitted, so the process of calibration is simplified, and the precision of calibration is improved at the same time.

Abstract: Gough-Stewart platform (GSP) has been extensively used as motion simulators. In order to get good performance of the motion simulators, the dynamic characteristics are needed to be considered in the design process. This paper established a dynamic dexterity index based on the generalized mass matrix in the joint space, which is invariant under the change of units and has a physical meaning. The dynamic dexterity indexes can also be established in the similar way as other parallel robots with the only pure active joints. In the last, a motion simulator is optimized based on the dynamic dexterity index to satisfy the customer’s requirements by using real-coded genetic algorithms.

Abstract: This work uses a Wireless Sensor Networks(WSN) module to design the device of driving cars astern. The WSN node integrates MCU CC2430 and MCU C8051F120. CC2430 has 2.4 GHz IEEE 802.15.4 compliant RF transceiver. The device of driving cars astern can play a more important role when CC2430 communicates with C8051F120. This paper shows how to design an device of driving car astern. It should be applied widely.

Abstract: The fluidic gyroscope sensitive principle with nozzle array structure was researched. Using the finite element method, according to the actual size, building an entity model, the finite element simulation was conducted by a series of procedures, such as meshing, loads applying and solving. Then the cavity flow field distribution was calculated in the different input angular rate. The results are as follows: In static status, airflow velocity shows a symmetry distribution through central axis of enclosure, the two hotwires endure the same current rate and current, then the bridge outputs zero. In the angular rate inputs, airflow velocity shows an asymmetry distribution through central axis of cavity. The two hotwires endure the different current rate, both of the hotwires current are changed with angular rate, then the bridge outputs a voltage with corresponding with the angular rate. The fluidic gyroscope sensitive principle with nozzle array structure is revealed by finite element method, which provides the foundation for the fluidic gyroscope structural and performance improvement.

Abstract: A steady output single-ended flyback switching power supply using L6561 current mode PWM controller designed in this paper. The designed circuit consists of single-ended flyback topology and based on the peak current PWM technology. The circuit has input voltage range from 85V AC to 265V AC and about output drive capability of 12V/2A. Based on the specific chip L6561, the novel single-ended flyback AC/DC converting circuit is adapted for mobile or office equipment, off-line battery chargers. The low-power Switched-Mode Power Supply (SMPS) are the most noticeable examples of application that this configuration can fit. The testing results show that the design of this method can reduce the switching power supply ripple, and ensure stable voltage output.

Abstract: This paper describes a circuit which can enhance the robustness of the subthreshold 6T SRAM bitcell. The proposed circuit can dynamically adjust the body voltages of the PMOS transistors in order to enhance the robustness of the subthreshold 6T SRAM bitcell by detecting the variation of the threshold voltage. The simulation results under 300mV in 65nm technology demonstrate that the mean values of the read and hold static noise margin (SNM) of the subthreshold 6T SRAM bitcell have been improved by 18% and 0.7%, respectively, meanwhile the standard values of the read and hold SNM have improved by 82% and 29.4%, respectively, by adopting the proposed circuit. Moreover, the proposed circuit functions well in a wide range of supply voltage from 0.2V to 0.5V.

Abstract: Based on PID controller, the closed-loop model of instantaneous torque for automotive brake test-bench was established, and then the instantaneous torque and the deviation function were calculated, furthermore, the genetic algorithm was adopted in order to get a global optimal solution and to optimize the parameters of the PID control system. So that the deviation function can be reduced or improved. By comparing the effect of control function, the causes for error volatility of the PID control system were derived, and the fitness function of genetic algorithm was determined reasonably. This algorithm can improve the reliability and accuracy of the control model effectively, and provide an effective method for testing the merits and integrated performance of automotive brake design.

Abstract: This paper proposes a multi-focus image fusion algorithm based on contrast ratio and discrete wavelet frame transform. Firstly, this algorithm uses wavelet transform to perform the wavelet decomposition of the source image, and then obtains the high-frequency sub-band coefficients after the discrete wavelet frame transform to reflect the details of the image, finally, gets the fusion image obtained by wavelet reconstruction. Using evaluation indicators of information entropy, standard deviation, average gradient and spatial frequency, it objectively evaluates the fusion quality of this algorithm. The experimental results show that the quality and effect of the fusion image derived from the algorithm are significantly improved.

Abstract: In this paper, we present and analyze a new iterative method for solving nonlinear equations. It is proved that the method is six-order convergent. The algorithm is free from second derivatives, and it requires three evaluations of the functions and two evaluations of derivatives in each iteration. The efficiency index of the presented method is 1.431 which is better than that of classical Newton’s method 1.414. Some numerical experiments illustrate that the proposed method is more efficient and performs better than classical Newton's method and some other methods.

Abstract: As one of Linux development directions, embedded Linux has many achievements and mature products. Its stability, reliability and the high efficiency is being proved by the facts. Linux has a great potential in the embedded area, which is loved by many businesses, scientific research units. The embedded Linux opens the source code, provides technical support widely and has good extendibility, supports a lot of hardware. All these are the advantages of embedded Linux. Touch screen has been an important human-computer interaction device, for they are light, flexible and take up less space. Most mobile devices offer a touch screen which is used together with a pen in order to take the role of the mouse for application control. A kind of touch screen control system based on ARM and Linux is introduced in detail. Circuit diagram and touch screen working principle is given. In this paper, touch screen driver based on embedded Linux is designed, analyzed and transplanted. Finally, touch screen can be used normally after calibrating.