Rotary Control Research Articles

Difference-Based Mutation Operation for Neuroevolution of Augmented Topologies

In this paper, a novel search operation is proposed for the neuroevolution of augmented topologies, namely the difference-based mutation. This operator uses the differences between individuals in the population to perform more efficient search for optimal weights and structure of the model. The difference is determined according to the innovation numbers assigned to each node and connection, allowing tracking the changes. The implemented neuroevolution algorithm allows backward connections and loops in the topology, and uses a set of mutation operators, including connections merging and deletion. The algorithm is tested on a set of classification problems and the rotary inverted pendulum control problem. The comparison is performed between the basic approach and modified versions. The sensitivity to parameter values is examined. The experimental results prove that the newly developed operator delivers significant improvements to the classification quality in several cases, and allow finding better control algorithms.

Experimental investigation of the flow behind a circular cylinder controlled by combination of a rotary oscillation and a radial deformation

This paper describes an experimental work which consists of a structural analysis of the flow around a circular cylinder subjected to a radial deformation of the cross section, according to a sinusoidal law, combined to a rotary oscillation. Experiments were performed for a Reynolds number of Re = 2700. The control parameters are the amplitude of the rotary oscillation; 30, 60 and $$80^{\circ }$$ are considered, the relative rotary oscillation frequency ranging from 0 to 4.5, and the amplitude of the radial deformation, 5% and 7%. The qualitative and quantitative analysis of the near wake snapshots revealed that the structure of the wake depends strongly on the control parameters. Compared to the simple rotary oscillation control, it is established that the combination of the aforementioned technique and the radial deformation of the cylinder cross-section allows reduction of the formation zone length with a rate of 37% and its width by 35%, anticipating the closure of the wake around the cylinder and increasing the emission frequency with a rate of 30%. Addition of radial deformation induces apparition of a new vortices emission mode, consisting of shed small vortices instead of big coherent structures in absence of the radial deformation, the defragmentation of big vortices and the dislocation of the wake. These results suggest a substantial reduction in additional drag.

Rotation Speed Control of the Rotary Valve in MWD Tools Based on Speed Feedforward Compensation

The rotary valve speed control, seriously affected by the nonlinear characteristic of rotary valve load torque, affects the generation of drilling fluid pressure phase shift keying (PSK) signal and its quality. The calculation model feedforward of the load torque acts on the speed control system and enables the motor voltage to change according to the law of calculation model, and the linearization correction of the speed system is performed. Additionally, the flow measurement is introduced into the calculation model of the load torque to track the load torque change with the flow, suppressing the influence of large changes in flow rate on open-loop control of rotary valve speed. The closed-loop proportional-integral-derivative (PID) control is formed by negative feedback of speed, and the PID parameter value rule is established based on the rapid decay control of transient component in the rotary valve speed step response, which speeds up the tracking of the rotary valve speed following the control voltage pulse and reduces the distortion of the drilling fluid pressure PSK signal, increasing the frequency of the drilling fluid pressure carrier and improving the transmission rate of downhole information. Simulink simulation indicates that the closed-loop PID control of rotary valve speed can track the change of control voltage pulse quickly and strongly suppress the interference influences from flow measurement error and load torque calculation model deviation.

Research on High Precision Angle Measurement and Compensation Technology Based on Circular Grating

In this paper, the angle measurement method of high-precision circular grating is studied. The principle analysis of circular grating angle measurement, the principle analysis of multi reading head, and the design of rotary servo control system are carried out. After analyzing the error model of circular grating angle measurement, the research based on harmonic compensation model is carried out respectively. Aiming at the problem of zero crossing oscillation of compensation algorithm, the piecewise compensation strategy is designed, which fully demonstrates the application value of circular grating angle measurement method in high-precision angle measurement system.

Rotary Inertial Navigation Active Disturbance Rejection Controller Based on Adaptive Genetic Algorithm

The high-precision control of the rotary servo is an important way to improve the navigation accuracy of the inertial navigation system. This paper proposes a parameter tuning method of active disturbance rejection controller based on adaptive genetic algorithm. Specifically, in order to ensure that the genetic algorithm has strong capability of global search and convergence performance, it adjusts the mutation probability and crossover probability of the genetic algorithm according to the individual fitness. Compared with traditional PID controller, the simulation results show that the optimized active disturbance rejection controller (ADRC) has fast response speed, no oscillation and no static error. And finally it realizes faster and high-precision control on rotary inertial navigation.

Combined Anterior and Anterolateral Stabilization of the Knee With the Hamstring Tendons

Anterior cruciate ligament reconstruction allows good control of sagittal laxity but insufficient rotary laxity control. Our objective is to describe an original lateral extra-articular tenodesis using gracilis in addition to an intra-articular reconstruction using the semitendinosus in a short 4-strand graft. The principles are as follows: The femoral tunnel for intra-articular and extra-articular reconstruction is unique, the femoral attachment is posterior and proximal to the lateral epicondyle, the graft is under the lateral collateral ligament, and the tibial insertion is isometric from 0° to 60° between the Gerdy tubercle and the fibular head.

Inverse kinematic analysis of a fixture for fine alignment of central axis of top and bottom frame using simulation

In the field of robotics, the design and development of Stewart Platform is currently the widely discussed topic because of its complexity as well as the usefulness in many fields like military operations, biomedical, Stealth operations, etc. This research work focuses on designing of fixture using rotary actuators and Simulation of Stewart Platform in MATLAB. Fixture consists of controlling of different degrees of freedom of the module, precise linear as well as rotary motion and motor position controller for every degree of freedom and enhanced real time control of each module. Inverse kinematic analysis of a fixture using Sim-mechanics of MATLAB is carried out. This fixture has a unique design considering space constraints and weight constraints. Above research work for automatic alignment of parallel robot with a payload of @5kg can be useful for many applications.

マルチエージェントフロー環状交差確率交通流モデルと合流部信号制御

マルチエージェントフロー環状交差確率交通流モデルと合流部信号制御

On the rational form of rotary control diaphragms for steam turbines with industrial and cogeneration steam extraction

The Russian park of power steam turbines contains a large number of turbines with adjustable steam extraction from the flow path where rotary control diaphragms are used as flow controllers, which structurally easily fit into the flow path of these turbines. This method of regulating the steam flow rate is accompanied by a decrease in the efficiency of the subsequent stages of the turbine and causes the appearance, at reduced loads, of additional disturbing forces acting on the rotor blades. In the presented materials, a variant of a post-sampling stage with a radial rotary control diaphragm is considered. The performed mathematical modeling of the working fluid flows in such a stage showed that in this case, at all turbine loads, a relatively uniform velocity field is provided when steam enters the nozzle apparatus, which naturally entails the elimination of the noted drawbacks.

A Symmetric Group Control Dynamic Element Matching Method Applied in High Resolution SAR ADCs for Biomedical Applications

Capacitor mismatch plays an important part in the spurious-free dynamic range (SFDR) performance of high-resolution successive approximation register (SAR) analog-to-digital converters (ADCs). This paper presents a symmetric group control dynamic element matching (SGCDEM) method aiming at enhancing SFDR of SAR ADCs applied in biomedical applications. The proposed scheme symmetrically divides the capacitor array into four sub-DACs, using quantization results corresponding to each sub-DAC as rotary control codes to symmetrically control the rotation of the capacitors. In order to improve the energy efficiency and save chip area, the proposed method replaces the pseudo-random number generator (PRNG) with quantization results of ADC as the rotary control code. Moreover, split rotator technology is applied in the proposed scheme to reduce the number of multiplexers (MUX) used in the rotator, which introduces a low logic depth. The proposed architecture has been implemented on a 12-bit SAR ADC model in MATLAB in order to verify its performances. After taking a standard deviation of 1% for the unit capacitance into consideration, this method achieves above 77.3[Formula: see text]dB SFDR, enabling to correct the SFDR by more than 23.6[Formula: see text]dB compared with the structure without DEM.

Design of a robust controller for a rotary motion control system: disturbance compensation approach

This paper proposes a design of a robust controller for a rotary motion control system that includes a PID controller, a disturbance observer, and a friction compensator. Friction force versus angular velocity has been measured, and viscous, Coulomb friction and stiction components have been identified. With nominal PID (proportional- integral-derivative) controller, we have observed adverse effects due to friction such as excessive steady-state errors, oscillations, and limit-cycles. By adding a friction model as an augmented nonlinear dynamics of a plant, we are able to conduct a simulation study of a motion control system that matches very well with experimental results. The disturbance observer (DOB) based on simple and effective robust control theory has been implemented to make the rotary motion control system “robust” against inertia/load variations, external torque disturbances, and some of friction forces. Further performance enhancement of the DOB-based robust motion control system has been achieved by adding the friction compensator and experimentally verified.

Active fault tolerant control of turbofan engines with actuator faults under disturbances

Abstract In this paper, an active fault-tolerant control (FTC) scheme for turbofan engines subject to simultaneous multiplicative and additive actuator faults under disturbances is proposed. First, a state error feedback controller is designed based on interval observer as the nominal controller in order to achieve the model reference rotary speed tracking control for the fault-free turbofan engine under disturbances. Subsequently, a virtual actuator based reconfiguration block is developed aiming at preserving the consistent performance in spite of the occurrence of the simultaneous multiplicative and additive actuator faults. Moreover, to improve the performance of the FTC system, the interval observer is slightly modified without reconstruction of the state error feedback controller. And a theoretical sufficiency criterion is provided to ensure the stability of the proposed active FTC system. Simulation results on a turbofan engine indicate that the proposed active FCT scheme is effective despite of the existence of actuator faults and disturbances.

Active fault tolerant control of turbofan engines with actuator faults under disturbances

Abstract In this paper, an active fault-tolerant control (FTC) scheme for turbofan engines subject to simultaneous multiplicative and additive actuator faults under disturbances is proposed. First, a state error feedback controller is designed based on interval observer as the nominal controller in order to achieve the model reference rotary speed tracking control for the fault-free turbofan engine under disturbances. Subsequently, a virtual actuator based reconfiguration block is developed aiming at preserving the consistent performance in spite of the occurrence of the simultaneous multiplicative and additive actuator faults. Moreover, to improve the performance of the FTC system, the interval observer is slightly modified without reconstruction of the state error feedback controller. And a theoretical sufficiency criterion is provided to ensure the stability of the proposed active FTC system. Simulation results on a turbofan engine indicate that the proposed active FCT scheme is effective despite of the existence of actuator faults and disturbances.

Cross-axis control system design for borehole drilling based on damping optimum criterion and utilization of proportional-integral controllers

This paper presents a control system design methodology for the drill-string rotary drive and draw-works hoist system aimed at their coordinated control for the purpose of establishing a fully-automated mechatronic system suitable for borehole drilling applications. Both the drill-string rotary drive and the draw-works hoist drive are equipped with proportional-integral (PI) speed controllers, which are readily available within modern controlled electrical drives. Moreover, the rotary speed control system is equipped with torsional active damping system and drill-string back-spinning prevention scheme for the case of stuck drill-bit scenario, whereas the draw-works-based drill-bit normal force control system is extended with the auxiliary control system aimed at timely prevention of the drill-string torsional overload. The design of proposed control systems has been based on suitable reduced-order control-oriented process models and a practical tuning methodology based on the damping optimum criterion aimed at achieving the desired level of closed-loop system damping. The functionality of the proposed cross-axis control system has been systematically verified, first by experimental tests of individual rotary/vertical axis control systems on a downscaled laboratory experimental setup, followed by thorough simulation study of the overall control system for realistic scenarios encountered in the field.

Efficient preservation of sprouting vegetables under simulated microgravity conditions.

The effectiveness of a simulated microgravity environment as a novel method for preserving the freshness of vegetables was investigated. Three types of vegetables were selected: vegetable soybean, mung bean sprouts, and white radish sprouts. These selected vegetables were fixed on a three-dimensional rotary gravity controller, rotated slowly. The selected vegetables were stored at 25°C and 66% of relative humidity for 9, 6, or 5 d while undergoing this process. The simulated microgravity was controlled utilizing a gravity controller around 0 m s-2. The mung bean sprouts stored for 6 d under simulated microgravity conditions maintained higher thickness levels than the vegetable samples stored under normal gravity conditions (9.8 m s-2) for the same duration. The mass of all three items decreased with time without regard to the gravity environment, though the samples stored within the simulated microgravity environment displayed significant mass retention on and after 3 d for mung bean sprout samples and 1 d for white radish sprout samples. In contrast, the mass retention effect was not observed in the vegetable soybean samples. Hence, it was confirmed that the mass retention effect of microgravity was limited to sprout vegetables. As a result of analysis harnessing a mathematical model, assuming that the majority of the mass loss is due to moisture loss, a significant difference in mass reduction coefficient occurs among mung bean sprouts and white radish sprouts due to the microgravity environment, and the mass retention effect of simulated microgravity is quantitatively evaluated utilizing mathematical models. Simulated microgravity, which varies significantly from conventional refrigeration, ethylene control, and modified atmosphere, was demonstrated effective as a novel method for preserving and maintaining the freshness of sprout vegetables. This founding will support long-term space flight missions by prolonging shelf life of sprout vegetables.

Design and Development of Fuzzy-PID Controller for Four-Wheeled Mobile Robotic Stability: A Case Study on the Uphill Road

Design intelligent control to maximize the performance of the Four-Wheeled Mobile Robot (FWMR) in case of uphill road problems. The variation of slope angle and load variation on the uphill road is applied to know the performance of the automatic control system on FWMR. The research is divided into three two covering, system identification, design system and simulation testing. The Rotary speed control system response with fuzzy-PID control method has a good performance by anticipating various tilt angle 5 o . The system can through uphill with loads 11N with a steady time and fast travel time. The best travel time in the 5 o tilt angle condition is 2 seconds with a 4m circuit length. This research concludes that fuzzy-PID control can be implemented and increase the dynamic response of the FWMR effectively on the uphill road problems .

Rotary Ventricular Assist Device Control With a Fiber Bragg Grating Pressure Sensor

Current ventricular assist devices (VADs) are rotary blood pumps used to treat end-stage heart failure. VADs are operated at a constant speed that is manually adjusted by a clinician based on the patient's cardiac demand during routine medical examinations. VADs operated at a constant speed have inadequate passive flow regulation due to the inherent mechanical pressure-flow characteristics of the pump; this can lead to harmful situations where the VAD is overpumping or underpumping. Typically, patients on long-term VAD support are discharged to an outpatient setting where the VAD speed can remain the same for weeks or months at a time, impacting patient safety and quality of life. Previously, physiological controllers for VADs have been proposed, which automatically adjust VAD speed to meet patient cardiac demand. Clinical implementation of physiological control is currently hindered by the lack of clinically available, implantable, and continuous hemodynamic sensors. This study describes the physiological control of a VAD using a fiber Bragg grating (FBG) sensor previously developed for measuring VAD inlet pressure. The FBG sensor was used as a feedback to a Starling-like physiological controller, and the control quality was compared against the same controller with feedback from a nonimplantable industrial pressure sensor (Omega sensor). Experiments were conducted in a bench-top cardiovascular simulator under various simulated patient scenarios. The average steady-state difference in VAD flow across all experiments was 0.1 L/min with a maximum difference of -0.4 L/min. Similarly, the average steady-state difference in left ventricular end-diastolic pressure was 0.02 mmHg with a maximum difference of -0.2 mmHg. The clinically insignificant differences found between the two feedback methods indicate that the FBG pressure sensor is viable for the physiological control of VADs.

Mathematical‐based control method and performance analysis of a novel hydromechatronics driving system micro‐independent metering

This paper aims to investigate the performance of a hydraulic actuator controlled by the novel system microindependent metering (MIM). This analysis has been performed by comparing the models of two systems which are the traditional independent metering (IM), which depends on poppet valve, and the new hydro‐mechatronics system MIM, which relies on a stepped rotary flow control valve. In general, IM is a hydraulic control system which guarantees a separation between the meter‐in and the meter‐out of the hydraulic actuator. A Valvistor valve, a special type of Poppet valves, was developed to be embedded into the IM system. This valve has controllability and stability shortcomings which prevent the system from spreading in the industrial applications. The Valvistor valve performance is highly affected by the fluid disturbances because the fluid is considered as a part of its control elements. A stepped rotary flow control valve has been developed to control hydraulic flow rate. The valve composed of a rotary orifice attached to a stepper motor. Using this valve instead of the traditional poppet type has led to a new configuration, which is termed by MIM. This form improves the hydraulic cylinder velocity performance by rejecting the fluid disturbances effect on the control circuit.

Development of a novel rotary flow control valve with an electronic actuator and a pressure compensator valve for a gas turbine engine fuel control system

This paper presents a new rotary proportional flow control valve with Cam-Nozzle configuration. The rotating cam against the fixed nozzle changes the flow area and then can meter the fuel flow. This valve equipped with a pressure compensator plunger type valve to retaining constant pressure difference across the flow control or metering valve. The cam shaft directly coupled to an electronic servomotor type rotary actuator and then it is possible to apply digital control techniques such as pulse width modulation (PWM) in this control system. This new valve configuration is developed for an electro hydro mechanical fuel control system in a gas turbine engine. In addition to aero engine application, this type of flow metering valve can widely be used in industrial hydraulic systems. In this unit, the output flow is proportional to the cam's angular position (or throttle command) and it is not sensitive to pressure fluctuations at nozzle inlet and outlet. The aim of this new design is to modify a manual single adjusted hydro-pneumatic fuel control unit to obtain a new electro-hydraulic fuel control system for a gas turbine engine. The main innovations in the presented fuel metering unit include new design of the rotary valve opening shape (Cam-Nozzle) without metal to metal contact, use of a rotary electronic actuating mechanism and also direct coupling between the actuator and the rotating cam. The increased fuel metering precision in the new flow control valve has improved the ultimate control accuracy of system. A computer simulation software based on the proposed model, is performed to predict the steady state and transient performance and to analyze effect of important design parameters on valve outlet fuel flow and obtain the final design parameters. The validity of the proposed valve configuration is assessed experimentally in the steady state and transient modes of operation. The results show good agreement between simulation and experimental in both modes (max. 4% deviation).

Attitude control of an inverted-pendulum-type robotic wheelchair to climb stairs considering dynamic equilibrium

The wheelchair is the major means of transport for elderly and physically disabled people in their daily lives. However it cannot overcome architectural barriers such as curbs and stairs. In this study, we developed an inverted-pendulum-type robotic wheelchair for climbing stairs. This wheelchair has a seat slider and two rotary links between the front and rear wheels on each side. When climbing stairs, the wheelchair rotates the rotary links while maintaining an inverted state of a mobile body by controlling the position of the center of gravity using a seat slider. In previous research, we confirmed that the wheelchair can climb by applying the control method consisting of a center-of-gravity control phase and rotary link control phase. However, it took approximately 15 s to rotate the rotary links during climbing because faster climbing causes the movement of wheels and the wheelchair to fall. This paper focuses on a control method to restrain the movement of the wheels when the stair climbing speed is increased. We realized that the movement was caused by forces acting on the pitch angle, such as the inertial force and the reaction of the driving force. We proposed the method considering the dynamic equilibrium of the pitch angle and confirmed the effect of the restraining wheels’ movement when the proposed method was applied.