Acceleration feedback control (AFC) enhanced by disturbance observation and compensation (DOC) for high precision tracking in telescope systems

Abstract In this paper, a cascade acceleration feedback control （AFC） enhanced by a disturbance observa- tion and compensation （DOC） method is proposed to improve the tracking precision of telescope systems. Telescope systems usually suffer some uncertain disturbances, such as wind load, nonlinear friction and other unknown disturbances. To ensure tracking precision, an acceleration feedback loop which can in- crease the stiffness of such a system is introduced. Moreover, to further improve the tracking precision, we introduce the DOC method which can accurately estimate the disturbance and compensate it. Furthermore, the analysis of tracking accuracy used by this method is proposed. Finally, a few comparative experimental results show that the proposed control method has excellent performance for reducing the tracking error of a telescope system.

A new PC control software for ZLS-Burris gravity meters

The previous operation of the ZLS-Burris gravity meter using a PDA already provides a significant improvement of the operation of a metal spring gravity meter. But in the practical field work the observer usually wishes more information about the measurement and the collected data. This situation sug- gested an improvement of the software and computer hardware. The goal was to develop a small useful PC tool that eliminates these deficits. However, it resulted in a very extensive application software, which was developed during 2011-2015. Along the way, some unwanted effects of the original control circuit were detected. Therefore as a last step a complete new control circuit for the feedback system was developed. This new circuit is fast and smooth and without resonance effects to the system. The algorithm parameters can be specifically adapted to the specific gravity meter. The software has a security system that ensures the user, depending on his level of knowledge, a limited access to the software options. Furthermore, a customer project management system is integrated. The observer, the gravity meters, the projects and maps can be assigned. Several ZLS Burris gravity meters can be managed. A large station data management is integrated. Every station has up to more than twenty parameters, such as the mandatory coordinates or supplementary pictures of the station. External storage and documentation of the measurements are possible with extra modules. In addition the maintenance of the gravity meter system is significantly improved. The motor control of the early ZLS Burris gravity meter is also improved. The complete rotation is displayed on the screen. Finally, two survey examples show the advantages of the software related to the accuracy and the time needed for a measurement.

Acceleration feedback of a current-following synchronized control algorithm for telescope elevation axis

This paper proposes a dual-motor configuration to enhance closed-loop performance of a telescope control system. Two identical motors are mounted on each side of a U-type frame to drive the telescope elevation axis instead of a single motor drive, which is usually used in a classical design. This new configuration and mechanism can reduce the motor to half the size used in the former design, and it also provides some other advantages. A master-slave current control mode is employed to synchronize the two motors. Acceleration feedback control is utilized to further enhance the servo performance. Extensive experiments are used to validate the effectiveness of the proposed control algorithm in synchronization, disturbance attenuation and low-velocity tracking.

A Message-array-based Mechanism for Tracking Control Effects in Supervisory Control Software

Supervisory control is a very popular paradigm for computer-controlled systems. Knowledge and tracking the control effect of every control operation is crucial to the control tasks. In the paper, we present a message-array-based mechanism to track control effects in supervisory control software. A novel data type, message array, is designed to efficiently support this tracking mechanism. The operation algorithms, adding algorithm （AA）, removing algorithm （RA）, and scheduler algorithm （SA） are proposed to operate the tracking messages in message array, which forms the special first input X output （FIXO） strategy of message array. Automatically tracking, recording, and rolling back are the characteristics of our tracking mechanism. We implement this messagearray-based mechanism on the famous human machine interface （HMI） software platform-proficy iFix, and construct experiments to evaluate the performance of the mechanism in various cases. The results show our mechanism can be well satisfied with supervisory control software.

Operation Control of a High-resolution Plasma Imaging System in KT5D Torus

This paper describes the control software together with the operational hardware, which successfully realizes the operation of a new fully programmable imaging system with high spatial and temporal resolutions on the KT5D magnetic torus, for observing the visible l ight emission from the plasma discharge.

A general observatory control software framework design for existing small and mid-size telescopes

A general framework for observatory control software would help to improve the efficiency of observation and operation of telescopes, and would also be advantageous for remote and joint observations. We describe a general framework for observatory control software, which considers principles of flexibility and inheritance to meet the expectations from observers and technical personnel. This framework includes observation scheduling, device control and data storage. The design is based on a finite state machine that controls the whole process.

A Survivability Routing Mechanism in SDN Enabled Wireless Mesh Networks:Design and Evaluation

In software-defined networking,the separation of control plane from forwarding plane introduces new challenges to network reliability.This paper proposes a fault-tolerant routing mechanism to improve survivability by converting the survivability problem into two sub-problems:constructing an elastic-aware routing tree and controller selection.Based on the shortest path tree,this scheme continuously attempts to prune the routing tree to enhance network survivability.After a certain number of iterations,elastic-aware routing continues to improve network resiliency by increasing the number of edges in this tree.Simulation results demonstrate this fault-tolerant mechanism performs better than the traditional method in terms of the number of protected nodes and network fragility indicator.

Software Reliability Experimentation and Control

This paper classifies software researches as theoretical researches, experimental researches, and engineering researches, and is mainly concerned with the experimental researches with focus on software reliability experimentation and control. The state-of-the-art of experimental or empirical studies is reviewed. A new experimentation methodology is proposed, which is largely theory discovering oriented. Several unexpected results of experimental studies are presented to justify the importance of software reliability experimentation and control. Finally, a few topics that deserve future investigation are identified.