The rate-monotonic scheduling algorithm is a static scheduling algorithm for periodic tasks, but the classic rate-monotonic scheduling algorithm only determines the task's priority by its period, the deadline of long period and important tasks can not be guaranteed. Here, a new static scheduling algorithm called DPSS. The integrated priority tasks obtained by calculating the two parameters-running time and importance, and at last the integrated priority will be classified by grouping. Through theoretical analysis and experimental results analysis, the method reduces the task deadline missing ratio, and could be more effective in real-time task scheduling.
An algorithm for movement images is introduced in this paper. The algorithm is based on lifting wavelet transform and fit to detect low contrast objects and movement object track. In the foundation, the new wavelet filters are constructed by using the training target images. At the present time, it has been widely used as a powerful tool, such as image compression, noise reduction and feature extraction etc. Contrasting to detection algorithm, there are some advantages, such as simple computing, higher probability and fast speed. The results illustrate the reference image of movement targets in machining is precisely tracked and detected by the algorithm. It shows that the proposed algorithm is precise and effective. Through applying the method in machining, the problems can be discovered and corrected timely. It can insure manufacturability and assembly. In mechanical manufacturing, the waste can be reduced and cost can be depressed, productivity can be improved.
This paper proposes a new distance function - power spectral density divergence to monitor machine condition .The distance function carries full information of time series model ARMA (m, n). The calculating example shows that it is more sensitive than I-divergence, J-divergence, and Bhattcharyya information distance to the changes of machine conditions.
Wireless sensor networks are appealing to researchers due to their wide range of application. This paper proposes Variable Grid-quorum Pattern MAC protocol (VGP-MAC), an adaptive, asynchronous and low-latency MAC protocol designed for wireless sensor networks. VGP-MAC improves the pattern and timeslot schedule, which make nodes save energy by the proper sleep mechanism according to the nodes' own traffic. And the grid quorum-based mechanism solves the asynchrony in the multi-hop wireless sensor network. This paper develops a better pattern and schedule generation schemes with less state transformation frequency. The analytical and experimental results show that VGP-MAC obtains more energy savings and reduces the latency.
Dynamic testing is actually testing during the course of vehicle emissions, reflecting the real situation. Through the integration of detection equipment and analysis software, it realized real-time detection, data analysis and troubleshooting. Using single-chip microcomputer control technology development, it designed microcontrollers and gas sensors as the core of the hardware system. Using embedded C language, it designed software system of according with national emission standards, realized the PC and the realization of hardware interconnection, completed dynamic testing, calibration and communications functions, etc. It used wireless communication technology for data transmission, thus saving space and line interference. Promoting the process of automobile exhaust emission control in China, the study provides new ideas of management of vehicle emissions.
Resource management and scheduling using economic-based principles and market-oriented models have been proven to be useful for scheduling tasks in Computing Grid. However, most studies only focus on the single objective of either cost or makespan. In this paper, we consider both cost and makespan, and focus on scheduling parallel tasks from Grid users considering a commodity market. A cost and time balancing algorithm, called MMCTB, which is based on Min-Min scheduling algorithm is proposed. The MMCTB minimizes and manages the execution cost and makespan of user tasks by a balancing formula and giving consideration to task urgency. The simulations reveal that the MMCTB has merits of needing less time and cost to complete the task, and high ratio of tasks executed within deadline by comparing with an enhanced Greedy heuristic.
In order to ensure the electricity output quality of one turbocharged diesel generator set under pulsed load, some measures were taken to control the speed regulating rate of original power machine. One main reason causing the big diesel speed regulating rate in experiment is the lack of air for combustion in the early period of pulse. The other reason is that the energy stored by set shafting parts when first pulse is loaded is less than other pulses, and the speed regulating rate in first pulse is comparatively big. Aiming at the two problems, strategies of electrical assisting turbo charging and increasing diesel speed before first pulse were put forward. The set dynamic performances before and after improvement were simulated on the basis of GT-power and Matlab. Simulation result shows that the set speed regulating rate decreases from 6.8% to 2.8% after improvement.
Mobile robot is an important branch of robotics research, and the azimuth of mobile robot is a very important moving process parameter. In this paper, we adopted multi-sensor integrated, combining digital magnetic compass, fiber optic gyro and photoelectric encode to estimate the azimuth of mobile robot, and putting each measurement result into Federated filter. We use Unscented Kalman filter as the sub-filter of the federated filter. This approach has been simulated under Matlab and the result proved that multi-sensor angle information based on the Federated filter can better estimated the orientation angle of mobile robot.
To solve the problem of high false alarm rate and low positioning accuracy in the gas leak location detection, a new method is designed, in which wavelet transform is used to extract gas leak negative pressure wave signal, the gas leaks and positioning can be detected by using the method of negative pressure wave combined with flow balance. An algorithm of extracting negative pressure signal through wavelet transform is proposed and a method of negative pressure signal-flow rate detecting and positioning is provided. A negative pressure wave-flow testing gas pipeline leak system based on wavelet transform is designed. The positioning accuracy of the system reaches ± 1% of pipe length, and the false alarm rate is reduced.
This paper presents the design and implementation of a target tracking test bed based on wireless sensor network (WSN). The test bed is made up of a group of ultrasonic sensor nodes for ranging, a robot as mobile target for tracking and a laptop as base station for visualization. A new incremental optimization algorithm based on trilateration as well as a kind of changeable periodic scheduling scheme is applied in the test bed to pursue excellent tracking performance. The experimental result shows that the test bed can track a moving target effectively.
The trajectory of a revolute welding robot with six joints was planned in order to make the trajectory smooth and working time optimal. The time intervals between each point to be welded in Cartesian space were coded in binary, and the trajectory was implemented using an adaptive genetic algorithm while considering constraints of displacement, velocity, acceleration and jerk of each joint. According to the optimal time intervals generated, the results of simulation on robot kinematics show that the method designed for robot trajectory planning can obtain the goal trajectory. This method can solve the premature convergence and slow convergence problems, comparing with the simple genetic algorithm.
A small bounded wave electromagnetic pulse (EMP) simulator is designed in this paper. Its maximum height is 240mm. The simulator provides the simulated high electromagnetic pulse (HEMP) environment for testing smaller objects such as cable and other electrical equipment in vehicles, under the condition of low source power. It adopts electromagnetic field modeling software MicroStripes to analysis property of the simulator. Results of simulation show that the electric field distribution in the working volume is uniform under the excitation of double exponential voltage pulse (peak voltage of the pulse is 12kV). The property of small bounded wave EMP simulator satisfies demand of relational standards. It is enough for testing smaller objects.
Facing the hard truths about energy, it is important for motors to save energy. As a high-quality energy-saving motor, PMSM is introduced in this paper. To the high-power PMSM, it expounds an intelligent control system from the driver to the inner algorithm, including both the hardware and the software components of the whole servo system. The vector control technique is introduced by creating the mathematical model of PMSM in different coordinate systems and giving the principle of coordinate transfer. And the analyses shows that the parameters in d and q axis are decoupling, the characteristic of torque control is linear, output torque is steady and speed range wide when the vector control technique is used. Finally it designed a typical electrical circuit for application by using the IGBT transistor and the IR2214 chips. Make full use of the advantages of STM32 MCU which is suited to electrical machine control to get an ideal results according to the reasonable theory and the typical algorithm we have took.
The development process of solar calorific clothing and its relevant subject fields are stated in the thesis, with respect to the key technical issues of heating and keeping temperature constant to be solved on solar calorific clothing, a kind of double closed loop control system of temperature and voltage is put forward. First of all, the output characteristic of solar photocells is analyzed and ways of selecting capacity of photocells are also supplied. Next, detailed formula deduction courses for the composition of temperature closed loop control system and the mathematical models of each link are given, and on the base of the design methods of typical II system, the design process of temperature regulators is presented concretely. Finally, such control method is tested and verified through a simulation experiment, and the results show that such system has superiority on the rapidity and static error of control and provides a reference method for the temperature control of solar calorific clothing.
Commercial vehicles have the characteristic of a high center of gravity and bulky dimension, so a lower threshold of rollover stability, resulting in vulnerable to rollover. First this paper sets up the rollover warning simplified model and acquires the dynamic rollover threshold. Second heavy commercial vehicle rollover warning algorithm is proposed based on prediction model and develop a real-time rollover warning controller which can perceive the rollover risk in the dangerous conditions. Finally the rollover warning controller is verified by the vehicle test. The test results show that the rollover warning algorithm works well and can remind the driver to take timely measures to avoid rollover occurred.
In the paper a novel improved immune genetic algorithm is proposed for thresholding image segmentation based on the maximum entropy. At first, the encoded mode is made and the maximum entropy function is selected as the key adaptation genetic algorithm. Then, with the method of regulating density in the immune arithmetic, the ICM algorithm is adopted and the better antibody is transfered to the next generation. And more, the parameter of cross operator and mutation operator are mended appropriately. In the end, Comparing with the standard genetic algorithm, the improved immune genetic algorithm can enhance efficiency of running, form the results of the experiment we can see that the improved algorithm has also some advantages, such as validity and practicability.
Output pressure and output strain are two most important performance parameters of dielectric elastomer actuators (DEAs). In this research, effective pressure was educed from the perspective of energy conservation. A concept circular acrylic-polymer-based actuator was built with VHB4910 and graphite-silicon-elastomer mixture. Several groups of contrast experiments were performed. Theoretical analysis and experiment results indicated that boundary conditions affected strain output of actuators greatly and DEAs can get its highest output strain under equibiaxial prestrain condition. Output strain was not always monotonously rise with the increase of prestrain, and an appropriate prestrain ratio can improve maximum output strain of actuators up to several times. The changing of prestrain during actuating process also affected output strain greatly and should not be ignored in the design and application of DEAs.
For the issue that applying traditional method of quantization factor fuzzy control for magnetic powder clutch in the engaging process during vehicle starts can not achieve optimization, a method of using variable learning factor partial swarm to optimize quantization factor of fuzzy controller has been put forward, the optimized quantization factor changes with the environmental condition as well as load and it can track the parameters' change of fuzzy controller in real time, making the robustness and control accuracy of the fuzzy controller improved. The simulation results show that in the engaging process of magnetic powder clutch during vehicle starts, variable learning factor particle swarm optimization fuzzy control algorithm can effectively reduce the maximum collision during vehicle starts and the sliding friction work in the process of clutch engagement comparing with the traditional fuzzy control algorithm.
