Control system design and flight testing for a miniature unmanned helicopter

There are many design methods for the multiloop control system, but a method to exactly evaluate the stability margin for multiloop control systems has not been established yet. It is very important for the designers to exactly know the stability margin of the flight control system, because it directly comes to bear on flight safety. Previous research has proposed the “-1/ξ locus” analysis method for the exact evaluation of the stability margin of multiloop flight control systems. -1/ξ is an open loop transfer function of multiloop control systems that is considered as an extension of that for single-loop control systems. In this paper, the relation between the response of the closed loop and the stability margin is considered by using the -1/ξ locus. Lateral-directional flight control system was taken for instance, important points to pay attention to use the -1/ξ locus method for designing the flight control system are presented.

Continuous rolling of plate and strip is a typical complex, multi-variable and multi-objective system, which has shown the characteristics such as complication, large-scale and close coupling increasingly. Therefore, it has become more and more difficult to design complex industrial control systems. This paper describes a multi-agent control system for a strip rolling process. In order to realize the distributed and intelligent control of the system, after analyzing the characteristics and structure of this control system, the multi-agent theory was applied and then a control strategy was designed based on multi-agent interaction. Finally, the partition method, the coordination mechanism, and the model structure of the multi-Agent control system for the strip rolling process were analyzed. This paper concludes with a new control structure and system for strip rolling process, which helps to build up the generally integrated model, to eliminate the coupling among control systems, and to realize more intelligent control.

MEMS-Based Low-Cost Flight Control System for Small UAVs

Rotorcraft flight control systems present design challenges which often exceed those associated with fixed-wing aircraft. First, large variations in the response characteristics of rotorcraft result from the wide range of airspeeds of typical operation (hover to over 100 kts). Second, the assumption of vehicle rigidity often employed in the design of fixed-wing flight control systems is rarely justified in rotorcraft where rotor degrees of freedom can have a significant impact on the system performance and stability. Proposed herein is a methodology for the design of robust rotorcraft flight control systems utilizing Quantitative Feedback Theory (QFI'), a technique which accounts for variability in the dynamic response of the controlled element in the design of robust control systems. It was developed to address a Multiple-Input-Single-Output (MISO) design problem, but was extended to the address the Multiple-Input-Multiple-Output (MIMO) flight control system (FCS) design problem of a UH-60 Black Hawk Helicopter. Inherent conservatism in this design technique leads to limitations in its utility. A modified QFI' approach proved a viable method for designing robust MIMO flight control systems. An analysis of the two flight control system design methodologies is presented.

Filtered dynamic inversion for altitude control of fixed-wing unmanned air vehicles

Research aircraft have become increasingly dependent on advanced control systems to accomplish program goals. These aircraft are integrating multiple disciplines to improve performance and satisfy research objectives. This integration is being accomplished through electronic control systems. Because of the number of systems involved and the variety of engineering disciplines, systems design methods and information management have become essential to program success. The primary objective of the system design/information tool for aircraft flight control system is to help transfer flight control system design knowledge to the flight test community. By providing all of the design information and covering multiple disciplines in a structured, graphical manner, flight control systems can more easily be understood by the test engineers. This will provide the engineers with the information needed to thoroughly ground test the system and thereby reduce the likelihood of serious design errors surfacing in flight. The secondary objective is to apply structured design techniques to all of the design domains. By using the techniques in the top level system design down through the detailed hardware and software designs, it is hoped that fewer design anomalies will result. The flight test experiences of three highly complex, integrated aircraft programs are reviewed: the X-29 forward-swept wing, the advanced fighter technology integration (AFTI) F-16, and the highly maneuverable aircraft technology (HiMAT) program. Significant operating anomalies and the design errors which cause them, are examined to help identify what functions a system design/information tool should provide to assist designers in avoiding errors.

: Current design techniques applied to aircraft flight control systems have been surveyed and the increasing use of modern control theory in the control system design of experimental technology demonstrator aircraft is described. The modern control system design methodology is seen to be particularly suitable for application to the design of controllers for complex, multivariable aircraft systems which are composed of dynamically interacting subsystems. These will typically include the flight control, propulsion and weapon systems. Some suggestions regarding the most appropriate form of future ARL involvement in this large and expanding area are made.

Preference-based optimum design of an integrated structural control system using genetic algorithms

Not so long ago, research in flight control was largely an algorithmic endeavor???-???the objective was to devise higher performance control laws. Such research still continues, but an additional imperative is now prominent. For many new flight control developments, the challenge is not so much to come up with the control algorithm; the existing literature describes how to do that sufficiently well. The new challenges are cost-efficiency and development time reduction. This chapter revises some of the basic technology for flight control systems and discusses how computational tools are now being used to ensure that new control systems can be affordably developed and deployed. The target vehicles for the flight control technology described are military aircraft and missiles. There are notable differences between the two, such as the use of different sets of actuators (in missiles, for example, reaction jets can directly control roll, pitch, and yaw). Flight control system design requirements also differ fundamentally for aircraft and missiles,due to the presence of a pilot in the former. As a consequence, control techniques can differ. Dynamic inversion???-???a form of feedback linearization???-???is a popular technique for aircraft flight control, whereas linear quadratic optimal control is commonly used for missiles. In either case, complications arise due to the fact that accelerometers and gyros are not located at the center of gravity of the vehicle. In some cases, performance and stability can be improved by appropriately locating the sensors. Simulation and analysis software is now essential for flight control design. The chapter discusses tools within the MATRIXx toolset that permit performance and robustness evaluation over a range of operating conditions. Today's tools allow aerospace engineers to graphically design a flight control s ystem, analyze its performance and stability, and generate autocode that can be ported directly to training simulators, hardware in the loop simulators, and the aircraft itself. Similar tools are in use in other industries too-see Ch. 15 for an automotive industry perspective. Further discussion on computer aided control system design can also be found in Ch. 3 which also outlines a flight control application. What lies ahead for flight control? This chapter concludes by noting the interest in, and the challenges associated with, uninhabited aircraft. This topic is also discussed in Ch 10 where focus is on multi-vehicle aerospace challenges.

Loiter Attack Munition Flight Test Program

Summary Aminoil U.S.A. Inc. (AUSA) operates a pipeline delivering geothermal steam to a Geysers. Lake County, CA, power plant by means of a distributed control system. Microprocessors located in the field squire data and transmit it digitally to a control building adjacent to the power plant. From this building the shift operator monitors and controls every well in the system, regulates the delivery pressure to the geothermal power plant, and controls the condensate reinjection system. This paper discusses design, operation, and future objectives of this control system. The design covers selection of the control system, data acquisition and control requirements for individual wells, pipeline over pressure relief system control, and condensate reinjection system. The operation of the steam pipeline since power plant start-up has been very favorable. Steam delivery pressure fluctuations are controlled to less than +0.5 psi (+/-4 kPa) under normal conditions. Shift operators are capable of responding to power plant upsets (turbine trips and load reductions) in minutes, minimizing steam venting to the atmosphere. Currently the geothermal steam pipeline is manually remote operated by a shift operator. This operation has provided valuable information for conversion to an unmanned computer control operation. This proposed unmanned computer control is discussed along with our methods of approach. Introduction Our project is in the Castle Rock Springs area of The Geysers field in California, approximately 100 miles (160 km) northeast of San Francisco. The operator supplies geothermal steam to a public utility's geothermal power plant rated at 138 MW gross, 133 MW net delivered to the transmission line. Twenty-three geothermal steam wells deliver a total of approximately 2,700,000 lbm/hr (340 kg/s) of steam at rated capacity. Individual well deliverabilities range from 40,000 to 325,000 lbm/hr (5 to 41 kg/s). Approximately 5 miles (8 km) of insulated pipe is required to deliver the necessary steam flow to the power plant. Individual wellhead pipelines vary in diameter from 10 to 18 in. (25 to 46 cm), depending on steam flow capability. The wellhead pipelines feed into 24- to 30-in. (61- to 76-cm) branch lines that connect into two 36-in. (91 -cm) main steam lines with separators for condensate and particle removal. These two 36-in. (91-cm) pipelines join to form a 48-in. (122-cm) header that delivers steam to the power plant. Along the pipeline, drip legs are positioned at low points to collect condensate. These drip legs are vented to the atmosphere to remove condensate during start-up or shutdown of the pipeline. To provide electrical power for the control system. a three-point 480-V electrical distribution system parallels the pipeline. Transformers step down the line voltage to 120 Vac at the wellheads. The remote control system used to monitor and control the geothermal steam pipeline was selected primarily as a mechanical H2S-abatement method for compliance with the Lake County Air Pollution Control Dist. (LCAPCD) regulations. During power plant outages and start-up conditions, all steam is vented to the atmosphere. The LCAPCD H S-abatement requirement for an unscheduled power plant outage is given in Fig. 1, Under these conditions the vented steam rate must be limited to 35 % of full flow within 1 hour after an outage. Further reduction to 10% of full flow is required if the power plant outage is expected to be greater than 7 hours. AUSA determined that only a remote control system capable of controlling all wells in the system could accomplish this flow reduction in the short time frame required. This paper presents our control system structure, design. operation, and proposed computer control. Control System Structure A Honeywell TDC-2000 control system combined with a Honeywell 4500 computer (super station) was selected and installed. JPT P. 989^

Modeling multi-loop intelligent pilot control behavior for aircraft-pilot couplings analysis

The article analyzes the state of the problem of creating highly functional bionic prostheses and the relevance of creating an adaptive control system for such prostheses based on the results of biosignal processing is shown. The advantages and disadvantages of the method of direct signals registration from the motor departments of the human cerebral cortex, the use of specialized so-called nerve cuffs to receive signals directly from peripheral nerve fibers, as well as implanted electrodes and registration of surface electromyographic signals (sEMG) were considered. Taking into account the non-invasiveness, safety and simplicity of technical implementation, the sEMG registration method was used as the basis for the work of the designed system. However, to increase the informativeness of the source material and the possibility of isolating a greater number of informative signs of individual phantom movements, it is proposed to use a multi-electrode system, and to ensure the adaptability of the prosthesis, it is proposed to implement sensory feedback in the proposed control system structure. For this purpose, it is proposed to use signals from tactile sensors, which will be placed at the prosthesis fingers ends. The structure of the control system is proposed, which includes two related data exchange channels and four main elements: a multielectrode system with sEMG sensors; a stump-receiving sleeve with actuators; a smartphone or PC with appropriate software; a bionic prosthesis with a processor module, motor drivers and a module for registering tactile sensors signals. It is proposed to implement the main structural elements, such as the multielectrode system, the stump-receiving sleeve and the bionic prosthesis itself, as separate independent elements that are interconnected via separate wireless data exchange channels. The elements of the multielectrode system for recording sEMG and sensory feedback signals were developed.

The article analyzes the distribution of control tasks in an aquaponic system and presents a three-level aquaponic system control system that combines automatic, automated and manual processes to ensure its efficient and adaptive operation. Based on the mathematical model of the aquaponic system, the analysis of the main control algorithms is carried out: periodic on/off, pulse width modulation (PWM) and P-controller. Their advantages, disadvantages and areas of application are considered. Using the mathematical model of aquaponics, the structure of the control system was created, which made it possible to model and analyze the main control algorithms and, based on it, develop recommendations for choosing a control system algorithm. Based on the modeling results, it was found that none of the considered algorithms provides optimal process parameters, requiring the future development of intelligent aquaponics control algorithms aimed at improving the efficiency of the system and the quality of the final product.

Control of complex Vertical Take-Off and Landing (VTOL) aircraft traversing from hovering to wing born flight mode and back poses notoriously difficult modeling, simulation, control, and flight-testing challenges. This paper provides an overview of a robust adaptive control for autonomous flight of the GL- 10 tilt-wing, tilt-tail, long endurance, VTOL aircraft control system. The GL-10 prototype aircraft efficiently combines two challenging mission objectives: long endurance and VTOL capability. The primary challenge for this project is not proving the basic aircraft configuration feasibility, as tilt-wings do indeed fly, but developing the flight control and flight test feasibility given schedule, resource constraints, and additional complexity from concurrent development for portions of the conceptual design, fabrication, and control development. The flight control system challenges are characterized by large flight envelope, highly nonlinear dynamics through transition regime and loiter requirement at just below the stall angle-of-attack while dealing with a sparse aerodynamics database resulting in large uncertainties. An L1 robust adaptive control was chosen to deal with these challenges. The paper present control law development and flight test results for the GL-10 VTOL tilt-wing, tilt-tail distributed propulsion UAV.