Position Feedback Control Method Research Articles

Development of free piston engine linear generator system and a resonant pendulum type control method

A free piston engine linear generator, which has the potential of the compact physique, high brake efficiency and high flexibility for fuel, has been developed. The developed free piston engine linear generator consists of a two-stroke combustion unit, an air-bounce chamber and a linear generator. The key technologies to realize the continuous operation are the control method and lubricating and cooling strategies. The proposed structure is featured as a piston shape with two different diameters coaxially, called a “W-shape” piston, which has an empty space inside for the oil cooling path. The performance of the structure is evaluated by a one-dimensional cycle simulation. The result indicates the possible output power of 10 kW and thermal efficiency of 42% using premixed charge compression ignition combustion strategy. The control method is another challenge of the free piston engine linear generator. This work proposes two strategies of the position feedback control method and the resonant pendulum type control method. The first method has the function of the feedback loops for the piston position and velocity so that the piston motion follows the reference profile calculated in advance. The experimental results show the limited range of operation because the fixed profile does not absorb the deviation of the piston motion due to the combustion deviation. The second method is based on the speed control without a fixed reference profile of the piston motion. The experimental result shows the robustness to the change in operating parameters such as ignition position, amount of fuel and desired power output.

Adaptive robust attitude control and active vibration suppression of flexible spacecraft

This paper presents the large angle attitude manoeuvre control design of a single-axis flexible spacecraft system that consists of a central rigid body and a cantilever beam with bonded piezoelectric sensor/actuator pairs as a flexible appendage. The proposed control strategy combines the attitude controller designed by the adaptive robust control technique with the active vibration controller designed by the positive position feedback control method. The desired angular position of the spacecraft is planned and an adaptive robust attitude control approach based on a projection type adaptation law is proposed to track the planned path and to achieve precise attitude manoeuvre control. Meanwhile, the positive position feedback control method is applied to actively increase the damping of the flexible appendage and to suppress the residual vibration induced by manoeuvre. Improved transient and steady state performance during and after large angle attitude manoeuvre can be both achieved by integration of the technical merits of all these control methods. Analytical and numerical results illustrate the effectiveness of this approach.

Forward and backward motion control of a vibro-impact capsule system

A capsule system driven by a harmonic force applied to its inner mass is considered in this study. Four various friction models are employed to describe motion of the capsule in different environments taking into account Coulomb friction, viscous damping, Stribeck effect, pre-sliding, and frictional memory. The non-linear dynamics analysis has been conducted to identify the optimal amplitude and frequency of the applied force in order to achieve the motion in the required direction and to maximize its speed. In addition, a position feedback control method suitable for dealing with chaos control and coexisting attractors is applied for enhancing the desirable forward and backward capsule motion. The evolution of basins of attraction under control gain variation is presented and it is shown that the basin of the desired attractors could be significantly enlarged by slight adjustment of the control gain improving the probability of reaching such an attractor.

Autonomous decentralized intelligent vibration control for large split-blanket solar arrays

Large split-blanket solar arrays are semi-rigid structures. It is difficult for this kind of structure to achieve vibration suppression. In order to solve this problem effectively, firstly, we use the finite element method to construct a dynamic model of a solar array with piezoelectric smart structure, and then we propose a new control method, namely the autonomous decentralized intelligent control to address the vibration control problem. Based on the concept of autonomous decentralized control presented in this paper, the control system can be divided into multiple autonomous subsystems. Each subsystem performs several control functions without external intervention. Numerical simulations are carried out to verify the proposed control strategy. The results indicate that this method is effective. Compared with the traditional positive position feedback control method, the attenuation time of the structural bending vibration can be reduced by half with the proposed method. Furthermore, the control system can perform well even under severe subsystem failure without external intervention.

Feedback control of electromagnetic actuator with three degrees of freedom using optical image sensors

AbstractRecently, multidimensional actuators have been attracting considerable interest as a solution for increases in size and weight. In this paper, we propose a position feedback control method using optical image sensors for an actuator with three degrees of freedom. The validity of this control method is verified on the basis of the measurement results. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(2): 47–54, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21290

Coordination control of dual‐arm modular robot based on position feedback using Optotrak3020

PurposeThe purpose of this paper is to present a novel and accurate coordination control method of dual‐arm modular robot based on position feedback using 3D motion measurement system – Optotrak3020. The end‐position accuracy of dual‐arm modular robot can be improved obviously.Design/methodology/approachBy means of Optotrak3020, the actual end‐position of dual‐arm modular robot is acquired and then returned to the robotic controllers, so the corresponding position error compensation is implemented. Through a 3D simulation and experiment of dual‐arm modular robot for tracking a trajectory of plane right triangle, the feasibility and validity of this control strategy are verified.FindingsThe coordination control of dual‐arm modular robot based on position feedback can be accomplished by means of Optotrak3020. The dual‐arm modular robot can accurately accomplish the task of positioning or tracking a reference trajectory.Practical implicationsThis real‐time position feedback control method with high control accuracy can be implemented on a PowerCube dual‐arm modular robot system. This method also can be applied to other dual‐arm robot systems, such as mobile robot with dual‐arm, humanoid robot.Originality/valueThe coordination control method of dual‐arm modular robot is presented based on end‐position feedback using Optotrak3020 motion measurement system. The platforms of simulation, communication and experiment are developed, respectively.

イメージセンサを用いた三自由度電磁アクチュエータのフィードバック制御

Recently, multidimensional actuators have been attracting considerable interest as a solution for increases in size and weight. In this paper, we propose a position feedback control method using optical image sensors for an actuator with three degrees of freedom. The validity of this control method is verified on the basis of the measurement results. © 2012 Wiley Periodicals, Inc. Electr Eng Jpn, 181(2): 47–54, 2012; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21290

Robust adaptive sliding mode attitude maneuvering and vibration damping of three-axis-stabilized flexible spacecraft with actuator saturation limits

This paper presents a dual-stage control system design method for flexible spacecraft attitude maneuvering control by use of on-off thrusters and active vibration suppression by embedded smart material as actuator. As a stepping stone, an adaptive sliding mode controller with the assumption of knowing the upper bounds of the lumped perturbation is designed that ensures exponential convergence or uniform ultimate boundedness (UUB) of the attitude control system in the presence of bounded parameter variation/disturbances and control input saturation as well. Then this adaptive controller is redesigned such that the need for knowing the upper bound in advance is eliminated. Lyapunov analysis shows that this modified adaptive controller can also guarantee the exponential convergence or UUB of the system. For actively suppressing the induced vibration, linear quadratic regulator (LQR) based positive position feedback control method is presented. Numerical simulations are performed to show that rotational maneuver and vibration suppression are accomplished in spite of the presence of disturbance torque/parameter uncertainty and saturation input.

Direct electrostatic levitation and propulsion of silicon wafer

A new type of contactless wafer manipulator, featuring "direct electrostatic levitation and propulsion of silicon wafer (DELP-SW)", has been successfully developed. The novel aspect of this manipulator is that a silicon wafer can be directly levitated and driven via electrostatic forces. In this paper, a brief review of basic principles is presented. This is followed by a description of the structure of a prototype DELP-SW mechanism, including electrode design, position feedback control method, driving principle, and the operational procedure. Experimental results, which demonstrate completely contactless transportation of an 8-in silicon wafer, are also presented.

Direct electrostatic levitation and propulsion

A new type of mechanism called direct electrostatic levitation and propulsion (DELF) has been successfully developed. The novel aspect of this mechanism is that an object can be directly levitated and driven via electrostatic forces, In this paper, a brief review of basic principles is presented. This is followed by a description of the structure of a prototype DELP mechanism, including electrode design, position feedback control method for levitation, driving principle and the operational procedure. Experimental results which demonstrate completely contactless transportation of a 3.5-in aluminum hard disk media are also presented.

Direct Electrostatic Levitation and Propulsion

A new type of mechanism featuring Direct Electrostatic Levitation and Propulsion (DELP) has been successfully developed. It can directly levitate and drive an object using electrostatic forces. A 3.5-inch diameter aluminum hard disk media has been suspended and transported. In this paper a brief review of the basic principle of the direct electrostatic levitation and propulsion is presented, followed by a description of the structure of the prototype DELP mechanism, including electrode design, position feedback control method for levitation, driving principle and the operational procedure. Experimental results which confirm the completely contactless levitation and propulsion are also presented.

Electrostatic levitator for hard disk media

This paper discusses developments in contact-less electrostatic levitators for use in ultra-high-vacuum (UHV) and clean environments. Presented is the first demonstration of an electrostatic levitation technology which can suspend disk-shaped metals and alloys. A 3.5-in diameter aluminum hard disk media has been suspended successfully by actively controlling an electrostatic attractive force acting on it. This paper describes the basic principle of electrostatic suspension, the structure of an experimental levitator, electrode design, position feedback control method, a linear system model, and operational procedures. In addition, experimental data are given to confirm the suspension. The electrostatic levitation technology will be a key technique in the developments of contactless and friction-free manipulation and transportation equipments utilized in UHV and clean environments, both of which are necessary for the manufacture of the new generation of semiconductor devices. >