scholarly journals Displacement Control of Flexible Structures Using Electrohydraulic Servo-Actuators

1985 ◽  
Vol 107 (1) ◽  
pp. 34-39 ◽  
Author(s):  
N. H. McClamroch
Keyword(s):  
Closed Loop ◽  
Force Feedback ◽  
Position Control ◽  
Feedforward Control ◽  
Flexible Structures ◽  
Direct Consequence ◽  
Linear Feedback ◽  
Acceleration Feedback ◽  
Control Forces ◽  
Actuator Control

A general approach to the displacement or position control of a nonlinear flexible structure using electrohydraulic servo actuators is developed. Our approach makes use of linear feedback of measured structural displacements plus linear feedback of the actuator control forces; a nonlinear feedforward function of the displacement command is also used for control. Based on a mathematical model of the closed loop, general conditions for closed loop stability are obtained. In the special case that the feedback is decentralized the stabilization conditions are stated in terms of simple inequalities; moreover, the stabilization conditions are robust to structural uncertainties since the conditions do not depend on explicit properties of the structure. Such robustness is a direct consequence of use of force feedback rather than, for example, acceleration feedback. Conditions are also developed for selection of the feedforward control to achieve zero steady state error; but this condition does depend on explicit properties of the structure. The theoretical results developed in the paper should provide a framework for advanced applications of control of mechanical systems using electrohydraulic servo-actuators.

Hybrid Target Tracking Manipulation Theories for Combined Force and Position Control in Open and Closed Loop Manipulators

2005 ◽  
Author(s):  
David J. Giblin ◽  
Zongliang Mu ◽  
ZhongXue Gan ◽  
Kazem Kazerounian
Keyword(s):  
Inverse Kinematics ◽  
Closed Loop ◽  
Force Feedback ◽  
Position Control ◽  
Parallel Manipulators ◽  
Joint Space ◽  
Loop Control ◽  
Joint Torques ◽  
Position Data ◽  
Direct Kinematics

This paper presents a new manipulation theory for controlling compliant motions of a robotic manipulator. In previous closed loop control methods, both direct kinematics and inverse kinematics of a manipulator must be resolved to convert feedback force and position data from Cartesian space to joint space. However, in many cases, the solution of direct kinematics in a parallel manipulator or the solution of inverse kinematics in a serial manipulator is not easily available. In this study, the force and position data are packed into one set of “motion feedback,” by replacing the force errors with virtual motion quantities, or one set of “force feedback,” by replacing motion errors with virtual force quantities. The joint torques are adjusted based on this combined feed back package. Since only Jacobian of direct kinematics or Jacobian of inverse kinematics is used in the control scheme, the computational complexity is reduced significantly. The applications of this theory are demonstrated in simulation experiments with both serial and parallel manipulators.

Implementation and Control of a Rotary Manipulator Driven by Soft Dielectric Electroactive Polymer

2013 ◽  
Vol 461 ◽  
pp. 352-357
Author(s):  
Hua Ming Wang ◽  
Hua An Luo ◽  
Bin Yang
Keyword(s):  
Strain Energy ◽  
Closed Loop ◽  
Force Feedback ◽  
Position Control ◽  
Nonlinear Differential Equations ◽  
Cerebellar Model Articulation Controller ◽  
Force Analysis ◽  
Force Output ◽  
Force Decomposition ◽  
And Control

Dielectric Electroactive Polymers (EAPs) are closest to natural muscles in terms of strain, energy density, efficiency and speed. A 2-DOF (Degree of Freedom) rotary manipulator driven by soft dielectric EAP is designed based on the biological agonist–antagonist configuration. Compact rolled actuators are chosen and implemented to drive the manipulator. To avoid the complicated solving of nonlinear differential equations, electromechanical characteristics of actuators are obtained by measuring their force behavior under different voltages and lengths. A CMAC (Cerebellar model articulation controller) neural network-based closed loop controller is developed to implement the position control of the manipulator and is evaluated by tracking a circle. According to the force analysis of the manipulator, forces of antagonistic actuators are determined by force decomposition to produce the desired force output, and then the voltages for actuators at certain lengths can be calculated through measured electromechanical characteristics. Experiment shows the measured force agrees well with the desired force. Due to the advantages of dielectric EAP, the manipulator has application prospects in areas of rehabilitation, force feedback or flexible manipulation without damage.

Target Tracking Manipulation Theories for Combined Force and Position Control in Open and Closed Loop Manipulators

2006 ◽  
Vol 129 (3) ◽  
pp. 326-333 ◽  
Author(s):  
David J. Giblin ◽  
Mu Zongliang ◽  
Kazem Kazerounian ◽  
ZhongXue Gan
Keyword(s):  
Inverse Kinematics ◽  
Closed Loop ◽  
Force Feedback ◽  
Position Control ◽  
Parallel Manipulators ◽  
Joint Space ◽  
Loop Control ◽  
Joint Torques ◽  
Position Data ◽  
Direct Kinematics

This paper presents a new manipulation theory for controlling compliant motions of a robotic manipulator. In previous closed loop control methods, both direct kinematics and inverse kinematics of a manipulator must be resolved to convert feedback force and position data from Cartesian space to joint space. However, in many cases, the solution of direct kinematics in a parallel manipulator or the solution of inverse kinematics in a serial manipulator is not easily available. In this study, the force and position data are packed into one set of “motion feedback,” by replacing the force errors with virtual motion quantities, or one set of “force feedback,” by replacing motion errors with virtual force quantities. The joint torques are adjusted based on this combined feedback package. Since only Jacobian of direct kinematics or Jacobian of inverse kinematics is used, the computational complexity is reduced significantly, and the control scheme is more stable at or near singular manipulator configurations. Furthermore, the complexities and oddities associated with hybrid control, such as nonuniformity of the space matrix and incompatibility of simultaneous position and force control in the same direction are circumvented. The applications of this theory are demonstrated in simulation experiments with both serial and parallel manipulators.

High dynamic digital control for a hydraulic cylinder drive

2021 ◽  
pp. 095965182110280
Author(s):  
Helmut Kogler
Keyword(s):  
Dynamic Response ◽  
Closed Loop ◽  
Position Control ◽  
Feedforward Control ◽  
Control Strategies ◽  
Frequency Control ◽  
Hydraulic Cylinder ◽  
Pulse Frequency ◽  
Pulse Code Modulation ◽  
High Dynamic

The control of hydraulic cylinders with digital hydraulic valves is often based on modulation principles like pulse-width modulation, pulse-code modulation, or pulse–frequency control. In many cases the dynamic drive performance using such control strategies is far below the natural dynamics of the system, since closed-loop controllers demand a certain phase margin for stability. However, some drive applications require a high dynamic response, which cannot be realized with common closed-loop concepts. In this article the design of a bang–bang feedforward control with regard to the dynamics of a hydraulic cylinder drive in accordance with the theory of optimal control is presented. The control achieves the maximum physical dynamic response and no remaining oscillations after the movement, which forms the basis of a high dynamic three-level position control for hydraulic drives. Furthermore, the influence of valve dynamics and pipe line dynamics with regard to the design of the digital valve control are considered by simulations.

Seismic Control Effect for Nonlinear Benchmark Building Using Passive or Semi-Active Damper

2002 ◽  
Author(s):  
Akira Fukukita ◽  
Tomoo Saito ◽  
Keiji Shiba
Keyword(s):  
Active Control ◽  
Passive Control ◽  
Feedforward Control ◽  
Electrical Power ◽  
Control Device ◽  
Control Effect ◽  
Damping Force ◽  
Active Device ◽  
Seismic Control ◽  
Control Forces

We study the control effect for a 20-story benchmark building and apply passive or semi-active control devices to the building. First, the viscous damping wall is selected as a passive control device which consists of two outer plates and one inner plate, facing each other with a small gap filled with viscous fluid. The damping force depends on the interstory velocity, temperature and the shearing area. Next, the variable oil damper is selected as a semi-active control device which can produce the control forces by little electrical power. We propose a damper model in which the damping coefficient changes according to both the response of the damper and control forces based on an LQG feedback and feedforward control theory. It is demonstrated from the results of a series of simulations that the both passive device and semi-active device can effectively reduce the response of the structure in various earthquake motions.

Linear Control Root-Clustering of Uncertain Systems

2014 ◽  
Author(s):  
S. Gutman
Keyword(s):  
Control Systems ◽  
Uncertain Systems ◽  
Closed Loop ◽  
Linear Control ◽  
Linear Control Systems ◽  
Linear Feedback ◽  
Important Class ◽  
Linear Feedback Control ◽  
Control Root ◽  
Clustering Criterion

In the design of linear control systems, it is desired to assign the closed loop spectrum in sub-regions (as opposed to locations) of the complex plane. The present paper establishes a matrix root-clustering criterion for an important class of regions, and develops a linear feedback control that assigns the closed loop spectrum in the desired region. This is done for both nominal and uncertain systems.

Torque Control of Electrorheological Fluidic Resistive Actuators for Haptic Vehicular Instrument Controls

2005 ◽  
Vol 128 (2) ◽  
pp. 216-226 ◽  
Author(s):  
M. A. Vitrani ◽  
J. Nikitczuk ◽  
G. Morel ◽  
C. Mavroidis ◽  
B. Weinberg
Keyword(s):  
Electric Fields ◽  
Closed Loop ◽  
Force Feedback ◽  
Haptic Feedback ◽  
Control Device ◽  
Torque Control ◽  
Feedback Mechanisms ◽  
Feedforward Loop ◽  
Integral Controller ◽  
Proportional Integral Controller

Force-feedback mechanisms have been designed to simplify and enhance the human-vehicle interface. The increase in secondary controls within vehicle cockpits has created a desire for a simpler, more efficient human-vehicle interface. By consolidating various controls into a single, haptic feedback control device, information can be transmitted to the operator, without requiring the driver’s visual attention. In this paper, the experimental closed loop torque control of electro-rheological fluids (ERF) based resistive actuators for haptic applications is performed. ERFs are liquids that respond mechanically to electric fields by changing their properties, such as viscosity and shear stress electroactively. Using the electrically controlled rheological properties of ERFs, we developed resistive-actuators for haptic devices that can resist human operator forces in a controlled and tunable fashion. In this study, the ERF resistive-actuator analytical model is derived and experimentally verified and accurate closed loop torque control is experimentally achieved using a non-linear proportional integral controller with a feedforward loop.

SET STABILIZATION OF A MODIFIED CHUA'S CIRCUIT

2005 ◽  
Vol 15 (02) ◽  
pp. 567-604 ◽  
Author(s):  
SHIHUA LI ◽  
YU-PING TIAN
Keyword(s):  
Equilibrium Point ◽  
Lyapunov Stability ◽  
Closed Loop ◽  
Invariant Set ◽  
Linear Feedback ◽  
Chua’S Circuit ◽  
Chua's Circuit ◽  
Linear Feedback Controller ◽  
Simulation Results ◽  
First Time

In this paper, we develop a simple linear feedback controller, which employs only one of the states of the system, to stabilize the modified Chua's circuit to an invariant set which consists of its nontrivial equilibria. Moreover, we show for the first time that the closed loop modified Chua's circuit satisfies set stability which can be considered as a generalization of common Lyapunov stability of an equilibrium point. Simulation results are presented to verify our method.

Design of Salt In-Bags Incasing Control Management System Based on Dual Closed-Loop Fuzzy Controller

2014 ◽  
Vol 596 ◽  
pp. 620-624
Author(s):  
Yan Bo Hui ◽  
Yong Gang Wang ◽  
Li Wang ◽  
Qun Feng Niu
Keyword(s):  
Management System ◽  
Closed Loop ◽  
Position Control ◽  
Product Information ◽  
Fuzzy Controller ◽  
High Reliability ◽  
Logistics Management ◽  
High Control ◽  
Control Management System ◽  
Control Management

According to auto-incasing equipment characteristic and control demand, a kind of salt in-bags incasing control management system was designed. The paper introduced the key technologies realization of the system. In the paper, a new fuzzy controller was designed to build a dual closed-loop fuzzy control system, realizing incasing goal site error on-line continuous correction. A logistics management module based on e-Tag was designed to realize product information traceable management. The experimental results show the system realizes accurate position control and RFID logistics management with high reliability and high control precision. The system can be popularized to other products packaging industry.

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