大涝坝气田油气井远程监控系统设计与实现

大涝坝气田地处戈壁腹地,自然环境差、油气井压力高、安全风险大。通过自动化、信息化手段实现油气井生产状况的远程监控是油田发展的必然趋势。依据油气井生产实际情况,设计了一套远程监控系统。该系统以三维力控ForceControl监控组态软件和安控RTU为软硬件核心,对油气井生产过程实现全天候自动监控。详细阐述了油气井远程监控系统设计思路,包括系统结构原理、硬件和软件设计。实践表明该系统具有很好的推广应用价值。     

Online stiffness estimation for robotic tasks with force observers

In this paper we propose an online stiffness estimation technique for robotic tasks based only on force data, therefore, not requiring contact position information. This allows estimations to be obtained in robotic tasks involving interactions with unstructured and unknown environments where geometrical data is unavailable or unreliable. Our technique – the Candidate Observer Based Algorithm (COBA) – uses two force observers, configured with different candidate stiffnesses, to estimate online the actual target object stiffness. COBA is embedded in a force control architecture with computed torque in the task space. The theoretical presentation of the algorithm, as well as simulation tests and experimental results with a lightweight robot arm are also presented.     

A robust two degree-of-freedom controller for systems with both model and measurement uncertainty

This paper presents a design method for robust two degree-of-freedom (DOF) controllers that optimize the control performance with respect to both model uncertainty and signal measurement uncertainty. In many situations, non-causal feedforward is a welcome control addition when closed loop feedback bandwidth limitations exist due to plant dynamics such as: delays, non-minimum phase zeros, poorly placed zeros and poles (Xie, Alleyne, Greer, and Deneault (2013); Xie (2013), etc. However, feedforward control is sensitive to both model uncertainty and signal measurement uncertainty. The latter is particularly true when the feedforward is responding to pre-measured disturbance signals. The combined sensitivity will deteriorate the feedforward controller performance if care is not taken in design. In this paper a two DOF design is introduced which optimizes the performance based on a given estimate of uncertainties. The controller design uses H_∞ tools to balance the controlled system bandwidth with increased sensitivity to signal measurement uncertainties. A successful case study on an experimental header height control system for a combine harvester is shown as an example of the approach.     

Dynamic surface control of a piezoelectric fuel injector during rate shaping

Fuel injection rate shaping is a strategy to improve fuel efficiency and reduce harmful emissions in diesel engines. Due to their fast response, piezoelectric fuel injectors are capable of rate shaping operation. This paper describes a model-based closed-loop controller of injection flow rate for a piezoelectric fuel injector. This within-an-engine-cycle control strategy utilizes a dynamic surface control scheme and shows an injection flow rate tracking capability. Practical issues with LabVIEW FPGA control implementation are also addressed. The performance of the controller is verified with simulation and experimental results at different rail pressures and desired injection rates. The experiments show a maximum error of total fuel per one injection event of 2.5%. A stability analysis is also included.     

Coupling geometric analysis and viability theory for system exploration: Application to a living food system

This paper addresses the issue of studying a food complex system in a reverse engineering manner with the aim of identifying the set of all possible actions that makes it reach a quality target with respect to manufacturing constraints. Once the set of actions is identified, several criteria can be considered to identify interesting trajectories and control policies. A viability approach, coupling the viability theory and a geometric approach of robustness, is proposed to study complex dynamical systems. It can be implemented for several types of systems, from linear to non linear or hybrid systems. The proposed framework was adapted to a living food system: a ripening model of Camembert cheese to identify the set of states and actions (capture basin) from which it is possible to reach a predefined quality target. Within the set of viable trajectories, particular trajectories that improve the Camembert cheese ripening process are identified using the proposed approach. The results are applied at a pilot scale and are discussed in this paper.     

An analysis,design and tuning of Cascade Control Systems in the presence of constraints in actuator and process outputs

In the presence of rate constraints in actuator, design of cascade controller based on the primary controller conditional integration can result into closed-loop system oscillations. Stability analysis, performed by the describing function technique and confirmed by simulation, demonstrates that the solution based on the Anti-Reset Windup Cascade Control System (ARW CCS) structure is successful. Design and tuning of the ARW CCS secondary controller is a standard ARW single-input single-output problem. In the present paper tuning is proposed for the ARW CCS primary controller. For the serial process modeling simple rules are derived and confirmed by experimental results, obtained on a drum type boiler of a 210 MWe lignite coal fired unit. General design of the ARW CCS is based on the parallel process modeling and optimization of the primary controller. Optimization is performed in the frequency domain, under constraints on the maximum sensitivity, multiplicative uncertainty bound and sensitivity to measurement noise. Simulation and experimental results on a laboratory thermal plant demonstrate effectiveness of the proposed optimization.     

余度系统中的动态同步和表决控制

在多通道余度系统的研究和应用中,同步问题是整个余度系统正确运行的基本保证。基于多交叉通道模型和同步时间的静态分配策略,提出动态时间容错方法。针对该方法,设计基于时间容错的动态表决控制算法,实现多通道系统中的动态同步。给出动态同步表决控制逻辑,用于控制表决时间并监测表决数据。理论分析和实验结果表明,时间容错的动态表决控制算法扩展了任务处理的时间窗口,与静态同步算法相比,可有效降低通道故障率,提高对瞬时干扰的抵御能力以及余度系统的可靠性。     

六种药剂防治向日葵白锈病试验研究

六种药剂防治向日葵白锈病田间药效试验结果表明,25%甲霜灵WP1000倍、50%安克WG2500倍的防效分别为87.6%和86.8%,显著优于64%杀毒矾WP800倍(防效75.7%),而52.5%抑快净WG1000倍、72%霜疫必克WP600倍和80%乙磷铝WP600倍的防效相当,不理想,均未达到50%。经方差分析证明处理间差异达到显著水平。     

低品质因数谐振筒的谐振频率测量系统

谐振筒式密度计的测量原理为谐振筒的谐振频率会随筒内液体密度的变化而变化,从而通过测量其谐振频率来达到测量其密度的目的。但由于低品质因数谐振筒在谐振频率附近的幅度与其他频率的幅度区分度太小,导致谐振难以实现。因此如何使低品质因数谐振筒达到谐振状态并测得其谐振频率,是谐振筒式燃油密度传感器激励系统的关键问题。激励系统以DSP为主控芯片,运用椭圆拟合的方法解决了低品质因数谐振筒式密度计激励系统的关键技术问题-增益测量和相位测量,运用原位计算节省了DSP大量的内存空间,同时运算量又较小。仿真结果表明,增益测量精度优于0.05%,相位测量精度优于0.05%,高于实际需要。系统在测量并记录了增益、相位差之后,利用相关算法实现了自动增益调节和自动相位调节,并实现了谐振筒的谐振,测得了其谐振频率。     

一类多时变时滞T-S模糊广义系统的容许控制

研究了一类具有多时变时滞的T-S模糊广义系统的容许控制问题。首先,给出了多时变时滞的T-S模糊广义系统数学模型,并且利用Lyapunov稳定性分析方法,得到了多时变时滞的T-S模糊广义系统的容许的一个充分条件,所得的结果对时变时滞的变化率没有限制。该充分条件可以通过严格线性矩阵不等式来求解。然后基于所给出的容许性定理,提出了状态反馈控制器的设计方法.最后,使用算例说明了所给方法的可行性和有效性。