Double-level ball-riding robot balancing: From system design,modeling, controller synthesis,to performance evaluation

In this research, a new robot, double-level ball-riding robot, is introduced. The robot consists of an upper ball-riding subsystem and a lower ball-riding subsystem. The robot’s dynamics model can be considered separately in two identical planes. Euler–Lagrange equation of motion is applied in order to obtain the dynamics model. Motors are included in the robot’s model. The model is then linearized. The robot’s parameters are identified. The robot’s prototype is manufactured and assembled. Linear Quadratic Regulator with Integral (LQR + I) controller is proposed and applied in order to balance both levels of the robot. The complementary and orientation transformation are used to fuse sensors in order to obtain robot leaning angles. Balancing performance of the developed double-level ball-riding robot is evaluated by simulations and experiments. The results show efficient control performance of LQR + I controller.     

High performance 14-bit pipelined redundant signed digit ADC

A novel architecture of a pipelined redundant-signed-digit analog to digital converter(RSD-ADC) is presented featuring a high signal to noise ratio(SNR), spurious free dynamic range(SFDR) and signal to noise plus distortion(SNDR) with efficient background correction logic. The proposed ADC architecture shows high accuracy with a high speed circuit and efficient utilization of the hardware. This paper demonstrates the functionality of the digital correction logic of 14-bit pipelined ADC at each 1.5 bit/stage. This prototype of ADC architecture accounts for capacitor mismatch, comparator offset and finite Op-Amp gain error in the MDAC(residue amplification circuit) stages. With the proposed architecture of ADC, SNDR obtained is 85.89 dB, SNR is 85.9 dB and SFDR obtained is 102.8 dB at the sample rate of 100 MHz. This novel architecture of digital correction logic is transparent to the overall system, which is demonstrated by using 14-bit pipelined ADC. After a latency of 14 clocks, digital output will be available at every clock pulse. To describe the circuit behavior of the ADC, VHDL and MATLAB programs are used. The proposed architecture is also capable of reducing the digital hardware. Silicon area is also the complexity of the design.     

利用Aspen模拟软件优化冷凝法油气回收工艺

利用Aspen模拟软件研究了冷凝法油气回收率与系统能耗的关系,并对冷凝回收工艺进行了优化。研究结果认为：油气回收工艺宜设计为三段制冷工艺。当其制冷温度依次为2℃、-30℃及-80℃时,即可以确保国家规定的95%以上的回收率,且系统能耗几乎控制在最低;当其制冷温度依次为2℃、-30℃及-120℃时,回收率可高达99.62%,而系统能耗不会剧增。     

一种Hawk仪器输出地震数据转储的方法

本文提出一种在Hawk仪器Transcriber系统中,外接安装有地震数据转储专用软件的计算机,在一定程度上能够提高和改善Hawk仪器Transcriber系统的数据转储效率,对Hawk仪器在大规模的数据采集应用时有一定的参考价值。     

Sub-channel shared resource allocation for multi-user distributed MIMO-OFDM systems

Well-controlled resource allocation is crucial for promoting the performance of multiple input multiple output orthogonal frequency division multiplexing （MIMO-OFDM） systems. Recent studies have focused primarily on traditional centralized systems or distributed antenna systems （DASs）, and usually assumed that one sub-carrier or sub-channel is exclusively occupied by one user. To promote system performance, we propose a sub-channel shared resource allocation algorithm for multiuser distributed MIMO-OFDM systems. Each sub-channel can be shared by multiple users in the algorithm, which is different from previous algorithms. The algorithm assumes that each user communicates with only two best ports in the system. On each sub-carrier, it allocates a sub-channel in descending order, which means one sub-channel that can minimize signal to leakage plus noise ratio （SLNR） loss is deleted until the number of remaining sub-channels is equal to that of receiving antennas. If there are still sub-channels after all users are processed, these sub-channels will be allocated to users who can maximize the SLNR gain. Simulations show that compared to other algorithms, our proposed algorithm has better capacity performance and enables the system to provide service to more users under the same capacity constraints.     

正独立式机械双流传动系统的分析

本文结合实例对正独立机械系统双流传动系统的各项性能进行了计算分析，指出在工程设计中采用这种传动系统的条件，达到正确认识和运用该传动系统的目的。     

Frequency frame approach on loop shaping of first order plus time delay systems using fractional order PI controller

This study proposes an analytical design method of fractional order proportional integral (FOPI) controllers for first order plus time delay (FOPTD) systems. Suggested technique obtains the general computation equations of controllers for such systems. These equations are used to tune controller parameters to meet specified frequency and phase properties to satisfy the stability of whole system. It is found that the designed controllers not only make the system stable, but also have positive effect on the performance and robustness of the system. Main contribution of the paper lays on this thought. There proposed a concept, “frequency frame” which encloses the curves between phase and gain crossover frequencies in Bode plot. Robustness of the control system can be improved by expanding or constricting the edges of this frame and flattening the curves inside the frame. Thus, any case that leads the system to instability can be avoided. Analytically derived equations are tested with proper examples and the results are shown illustratively. Advantages and disadvantages of the method are comparatively given.     

MIMO干扰信道中一种新的分布式迭代预编码算法

MIMO技术可以有效地提高通信系统的容量,但会带来很严重的用户间干扰问题。预编码技术以其能简化接收机和抑制干扰的作用将会在未来通信中扮演着重要角色。将多数据流的预编码矩阵设计转换成单数据流预编码矢量设计,提出了基于信干噪比最大的分布式迭代算法,以及将虚拟信干噪和最小均方误差方法相结合的迭代算法。数值仿真结果表明提出的算法可以有效提高系统容量。     

“互联网+”和“新工科”背景下榆林地方院校计算机专业教学改革研究

目前,榆林地方型院计算机专业人才模式单一化,结构不合理,学生创新能力较低,不利于榆林地方产业持续发展,为了发挥地方院校对地区经济发展和产业转型升级的支撑作用,提出了"互联网+"和"新工科"背景下榆林地方院校计算机专业教学改革研究,旨在帮助榆林地方院校全方位分析榆林市场发展的具体情况,以产业需求为导向,进一步优化榆林地方高校新工科背景下计算机专业的学科体系建设。     

基于环境影响的过程模拟分析

在工艺设计阶段避免和减少污染产生是从源头控制污染产生的有效方法,将环境影响最小集成到化工过程模拟设计中,是近年来清洁生产领域快速发展的一项技术。本文采用废物削减WAR算法来衡量工艺流程的环境影响指标,并将WAR算法与模拟软件Aspen集成,提供在工艺设计阶段的环境分析工具。同时,将集成的环境影响软件应用于乙烷制备乙烯工艺的环境影响分析。