Simple Control Algorithm Research Articles

ANALYSIS OF VOLTAGE FORMING METHODS FOR MULTIPHASE INVERTERS / DAUGIAFAZIŲ DAŽNIO KEITIKLIŲ ĮTAMPOS FORMAVIMO METODŲ ANALIZĖ

The article discusses advantages of the multiphase AC induction motor over three or less phase motors. It presents possible stator winding configurations for a multiphase induction motor. Various fault control strategies were reviewed for phases feeding the motor. The authors propose a method for quality evaluation of voltage forming algorithm in the inverter. Simulation of a six-phase voltage source inverter, voltage in which is formed using a simple SPWM control algorithm, was performed in Matlab Simulink. Simulation results were evaluated using the proposed method. Inverter’s power stage was powered by 400 V DC source. The spectrum of output currents was analysed and the magnitude of the main frequency component was at least 12 times greater than the next biggest-magnitude component. The value of rectified inverter voltage was 373 V. Article in Lithuanian. Santrauka Straipsnyje pristatomi daugiafazių variklių pranašumai, palyginus su trifaziais ir vienfaziais. Apžvelgiama variklių sandara ir pristatomi daugiafazių variklių apvijų tipai. Pristatomos variklių valdymo strategijos sugedus apvijos ar inverterio galios pakopos raktui. Pasiūloma daugiafazių dažnio keitiklių įtampos formavimo algoritmų vertinimo metodika. Matlab Simulink terpėje modeliuojamas šešiafazis dažnio keitiklis, kuriame veikia sinusinio impulso skvarbos moduliavimo įtampos formavimo algoritmas. Pagal sukurtą vertinimo metodiką įvertinami dažnio keitiklio modeliavimo rezultatai, pateikiamos išvados.

Research on Constant Velocity Extruding Process Control for 36,000-Ton Vertical Extrusion Press

Metal extrusion is one of the most significant methods in the field of plastic deformation. The 36,000-ton vertical extrusion press uses one-piece hot extrusion molding method to produce high-pressure, large-diameter, thick-walled, seamless, alloy-steel pipe, which is required by ultrasupercritical power generator units and the third generation of nuclear power plants. The main table (extruding platform) is driven by 36,000-ton thrust. The extrusion process is a typical nonlinear multivariable strong-coupling finite-time system. In this paper, we analyze and solve the large-scaled engineering control problems, including (1) discussion of the mechanical structure of the controlled object and the feature of multivariable strongly coupling for large-scaled parallel-driving hydraulic system, (2) research on the engineering practical simplified control algorithm for multivariable system and propose a way to solve the coupling problem of the hydraulic system, and (3) design of double closed-loop control of velocity and pressure for the new technology of constant velocity extrusion. In our paper, we have proven through practice that the traditional proportional intergral (PI) controlling method, with proper controlling strategy, is still the most efficient and practicable way for a large-dimension complex object in industry.

Adaptive block dynamic surface control for integrated missile guidance and autopilot

A novel integrated guidance and autopilot design method is proposed for homing missiles based on the adaptive block dynamic surface control approach. The fully integrated guidance and autopilot model is established by combining the nonlinear missile dynamics with the nonlinear dynamics describing the pursuit situation of a missile and a target in the three-dimensional space. The integrated guidance and autopilot design problem is further converted to a state regulation problem of a time-varying nonlinear system with matched and unmatched uncertainties. A new and simple adaptive block dynamic surface control algorithm is proposed to address such a state regulation problem. The stability of the closed-loop system is proven based on the Lyapunov theory. The six degrees of freedom (6DOF) nonlinear numerical simulation results show that the proposed integrated guidance and autopilot algorithm can ensure the accuracy of target interception and the robust stability of the closed-loop system with respect to the uncertainties in the missile dynamics.

MR 햅틱 큐를 이용한 차량 기어변속 보조장치의 성능평가

This paper proposes a driver supportive device with haptic cue function which can be applicable for vehicles adopting manual transmission system to transmit gear-shifting information to a driver by kinesthetic forces. This haptic cue function is implemented on accelerator pedal by utilizing magnetorheological(MR) fluid and clutch mechanism. In order to achieve this goal, an MR clutch mechanism is devised to be capable of rotary motion of accelerator pedal. The proposed MR clutch is then optimally designed and manufactured under consideration of spatial limitation of vehicles. After transmission torque is experimentally evaluated according to field intensity. The manufactured MR clutch is integrated with accelerator pedal and electric motor to establish the haptic cue device. Control performances are experimentally evaluated via a simple feed-forward control algorithm.

The Combined Effect of Missile IMU Shift, Model Following and Add-on SAC on the Autopilot Response

Proper location of the missile's inertial measurement unit renders the transfer function from the control surfaces to the acceleration measurement minimum-phase. Usually the poles and zeros of the missile actuators and rate gyros lie in the open left half plane. In this case the minimum-phase transfer function implies minimum-phase autopilot. Missile autopilots are designed to guarantee stability and performance throughout the flight envelope. The stability and performance are conflicting objectives. The final design is a compromise between stability margins and autopilot agility. In this paper the presented control architecture has the potential to resolve the conflict between robust stability and robust performance. The performance of the missile autopilot resulted from the combined effect of IMU location and reference model following can be further improved by using a simple Add-On adaptive control algorithm. The paper demonstrates the improved performance via example. The simple adaptive control (SAC) algorithm used in the paper involves the synthesis of parallel feedforward which guarantees that the controlled plant is almost strictly positive real (ASPR).

Output Feedback Control of a Class of MIMO Uncertain Nonlinear Systems

This paper propose output feedback control for a class of multi-input-multi-output (MIMO) uncertain nonlinear discrete-time systems. System uncertain nonlinearities are estimated online by constructing a linear disturbance observer, and output feedback control is developed based on the estimation to compensate the nonlinearities. An obvious advantage of the proposed control is that it possesses simple linear control algorithm, which is of great significance in engineering.

An application of predictive control to the Viikinmäki wastewater treatment plant

This paper deals with the development of a multivariable predictive control structure for improving the nitrogen removal of a biological wastewater treatment plant while reducing the operational costs. A simple dynamic matrix control algorithm is utilised as predictive controller and applied to a full-scale municipal wastewater treatment plant for controlling nitrogen concentrations at the end of the biological process. The complex calibrated model of the process is implemented in a commercial simulator that acts as a real-time testing platform for the proposed control structure, and allows the identification of the multivariable input-output model for the predictive control. Simulation results show the potentialities of the chosen predictive control, which allows the reduction of ammonia peaks in the effluent and at the same time permits a reduction of the energy consumption costs.

Model Predictive Control with Integral Action: A simple MPC algorithm

A simple Model Predictive Control (MPC) algorithm of velocity (incremental) form is presented. The proposed MPC controller is insensitive to slowly varying system and measurement trends and therefore has integral action. The presented algorithm is illustrated by both simulations and practical experiments on a quadruple tank MIMO process.

SVPWM Control of Cascaded H-Bridge Multilevel Inverters

To solve the problem of computational complexity in H bridge cascaded multilevel inverter (HBCMI) control, this paper proposes a simple space vector pulse width modulation control algorithm. Base on the topology configuration of HBCMI, the output voltage is deduced, which is the difference value between two-level inverter group output voltage formed by left bridge arms and by right bridge arms. The control complexity is independent of inverter voltage level and it is suitable to every voltage level. To verify the algorithms, different level cascaded H-bridge inverter drive systems were constructed and simulation results are present.

MODELING AND CONTROL DESIGN OF AN ANGUILLIFORM ROBOTIC FISH

In this paper, the modeling and control design of a biomimetic robotic fish is presented. The Anguilliform robotic fish consists of N links and N - 1 joints, and the driving forces are the torques applied to the joints. Considering kinematic constraints, Lagrangian formulation is used to obtain the dynamics of the fish model. The computed torque control method is applied first, which can provide satisfactory tracking responses for fish joints. Since this robotic fish is essentially an underactuated system, the reference trajectories for the orientation of the N links are planned in such a way that, at a neighborhood of the equilibrium point, the tracking task of N angles can be achieved by using N - 1 joint torques. To deal with parameter uncertainties that exist in the actual environment, sliding mode control is adopted. Considering feasibility and complexity issues, a simplified sliding mode control algorithm is given. A four-link robotic fish is modeled and simulated, and the results validate the effectiveness of reference planning and the proposed controllers.

Learning control for nonlinear systems in output feedback form

The class of single-input, single-output, minimum phase, nonlinear, time-invariant systems with unknown output-dependent nonlinearities, unknown parameters and known relative degree ρ is considered. The output regulation problem is addressed and solved in the presence of unknown periodic reference and/or disturbance signals of known common period. A simple learning control algorithm is designed which guarantees asymptotic output tracking for any initial condition belonging to any given connected compact set. It can be interpreted as a generalization of the classical PIDρ−1 control which solves the regulator problem when reference and disturbance signals are constant. As far as linear systems are concerned, global results are achieved.

A Novel BLDC-Like DTC Control Technique for Induction Motors

DC brushless motors are widely adopted for their simplicity of control, even in sensorless configuration, and their high torque density. On the other hand, induction motors are very economical due to the absence of permanent magnets; for the same reason they can easily be driven in the flux-weakening region to attain a wide speed range. Nevertheless, high dynamic induction motors drives, based on field-oriented (FOC) or predictive control, require large amounts of computing power and are rather sensitive to motor parameter variations. This paper presents a simple DTC induction motor control algorithm based on a well-known BLDC control technique, which allows to realize a high dynamic induction motor speed control with wide speed range. The firmware implementation is very compact and occupies a low amount of program memory, comparable to volt-per-Hertz- (V/f-) based control algorithms. The novel control algorithm presents also good performance and low current ripple and can be implemented on a low-cost motion control DSP without resorting to high-frequency PWM.

A Backstepping Simple Adaptive Control Application to Flexible Space Structures

Although the simple adaptive control (SAC) is widely studied both in theory and application in flexible space structure control and other control problems, it is restricted by the almost strictly positive real (ASPR) conditions. In most practical control problems, the ASPR conditions are not satisfied. Therefore, based on the SAC theory, this paper proposes a backstepping simple adaptive control algorithm which suits the system with arbitrary relative degree with no need of parallel feedforward compensator. The proposed control algorithm consists of decomposition of the arbitrary relative degree system into a known subsystem and an unknown ASPR subsystem which are connected in cascade, design of constant output feedback controller for the known subsystem, and implementation of backstepping method and SAC of the unknown ASPR subsystem. Inheriting the characteristics of the SAC, this method can be adaptive online for the parameter uncertainties. Then, the application of the proposed controller to large flexible space structure with collocated sensors and actuators is studied, and the simulation results validate the proposed controller. It is a new strategy to apply the classical SAC to high relative degree plants.

Active control of delaminated composite shells with piezoelectric sensor/actuator patches

Present study deals with the development of finite element based solution methodology to investigate active control of dynamic response of delaminated composite shells with piezoelectric sensors and actuators. The formulation is based on first order shear deformation theory and an eight-noded isoparametric element is used. A coupled piezoelectric-mechanical formulation is used in the development of the constitutive equations. For modeling the delamination, multipoint constraint algorithm is incorporated in the finite element code. A simple negative feedback control algorithm coupling the direct and converse piezoelectric effects is used to actively control the dynamic response of delaminated composite shells in a closed loop employing Newmark's time integration scheme. The validity of the numerical model is demonstrated by comparing the present results with those available in the literature. A number of parametric studies such as the locations of sensor/actuator patches, delamination size and its location, radius of curvature to width ratio, shell types and loading conditions are carried out to understand their effect on the transient response of piezoceramic delaminated composite shells.

New Approach for Noncircular Following Grinding of Crankshaft Pin

A new approach for the precise grinding of crankshaft pin is presented. In which, noncircular following strategy is investigated based on the motion model consists of horizontal feeding axis, additional lifting axis for wheel frame, and the active rotary axis for workpiece. The straight line relationship of wheel center, pin center and grinding point is ensured by the synchronism between standard arc interpolation motion of wheel frame and eccentric circular motion of pin section. Comparing with traditional tangential point tracing scheme, both constant grinding line-speed and simple control algorithm are fulfilled simultaneously. The negative effect of perpendicular deviation introduced by lifting axis is kinematically analyzed as well as the dynamic response error of servo system, and solving methods are carried out accordingly. By computer simulation and experimental test, the reported noncircular following strategy emerges good characteristics in the manufacturing of crankshaft, such as a strong adaptability for wheel wearing, simple motion control and high roundness precision.

Real-time vision-based control of weld pool size

A computer vision technique based on the real-time measurement and control of the upper surface or ‘topface’ weld pool size is discussed. The primary objective is to demonstrate the feasibility of using vision-based image processing to provide measurements and subsequent control of a weld's geometrical properties during the weld formation or molten phase. A novel reference feature – a correlation-based image analysis algorithm – has been developed, which may be configured to operate with a number of different welding processes. Upper surface weld pools with regulation via a simple classical feedback control algorithm have then been demonstrated to show how this approach may be used to improve weld uniformity and repeatability.

Conservation of Mobile Terminals’ Battery Life Using Dynamic Power Control Algorithm

Most of our activities today are tied around being able to make a call or connect to the Internet with our Mobile devices. However, to optimally utilize the network and deliver the needed satisfaction to the user the mobile device needs to be powered. Sadly most mobile devices are powered by energy-limited batteries, which impose a constraint on the mobile terminal optimal performance and on the network utility. As a result, special emphasis is now being laid on extending the battery life of mobile devices. In this work, we present a simple and effective power control algorithm, which conserves battery power by dynamically responding to real-time network conditions to adjust mobile terminal's transmit power. BER (bit error rate) in measurement reports obtained from signals received from the mobile terminal were used to estimate signal quality that helps to determine the network conditions and adjust mobile terminal's transmit power accordingly. Our algo- rithm was tested using simulation models, and our results were compared with the Stepwise algorithm, which is a popular power control algorithm in literature. A reasonable improvement was recorded for length of operation time and bat- tery-energy saved for the mobile terminal over stepwise algorithm.

Low-Cost Variable Speed Drive Based on a Brushless Doubly-Fed Motor and a Fractional Unidirectional Converter

The paper presents a low-cost variable-speed drive system comprising a brushless doubly-fed motor (BDFM) and a fractionally rated unidirectional frequency converter. A simple control algorithm is proposed for regulating the drive's speed and torque. A method of starting the BDFM in the cascade mode is presented and the starting performance is analyzed. The efficiency of the BDFM is discussed and the dynamic performance of the drive is verified by experimental results obtained from a 180 frame-size BDFM.

Super-Twisting Sliding Modes Tracking Control of a Nonholonomic Wheeled Mobile Robot

Abstract In this work a cascade robust tracking control for a nonholonomic wheeled mobile robot (WMR) is addressed, which is composed by an inverse dynamic control in the internal loop; and a robust kinematic control based in sliding modes control (SMC) techniques in the external loop. Even that invariance principle is inherent characteristic of the SMC, which assures robustness, the implementation of some SMC can be deteriorated by the so called chattering phenomenon, caused by presence of unmodeled dynamics, which effects can be worst if there is control saturation. Analysis results considering a realistic model of the WMR show that this is the case when a first order sliding modes control is applied to our framework. To circumvent the problem a robust kinematic control is proposed based on the super-twisting sliding modes control, which is a continuous second order sliding mode with a simple control algorithm.

Differential Steering Control for an Autonomous Mobile Robot: A Preliminary Experimental Study

In this paper, we present the first stage of a study in reducing errors occurred during the trajectory tracking by a nonholonomic mobile robot forwarding to a stable-target point. A preliminary experimental study is very important in order to verify the both velocity of DC motors with and without control the Pulse Width Modulation (PWM) for DC motors which control the velocities of left and right wheels of the mobile robot. Before any navigation control algorithm can be developed for navigate the mobile robot move in straight line to the stable target, both wheels should be set to move with the same velocity. From these preliminary experiments, we found that the PWM for left DC motor must be set higher than PWM for the right DC motor in order to achieve the least different velocity of both wheel. These PWMs setting for both DC motors then tested with a simple proportional control algorithm to verify effectiveness of selected PWM value for both DC motors in mission to navigate the mobile robot to the stable-target.