202 Dispatching rules for manufacturing job-shop operators

Abstracts 192 Dynamic Contrel Technique for Nonholonomic Systems A. Kapitanovsky, A.A. Goldenberg, J.K. Mills, pp 923.926 The paper addresses the synthesis of a smooth dynamic feedback for a class of nonlinear (nonholonomic) systems. The proposed technique provides uym...~ti.c stability and exponential convergence to a desired equilibrium manifold. The manifold is a function o( the generalized co-ordinates. Application of the proposed technique to control of a class of nonholonomic systems is presented. It is also shown that some nonholonomic systems (e.g., BrokeR's bilinear system), controlled by the ~ timeinvariant dynamic feedback, converge asymptoucelly to an arbitrary small ball eentrnd at the origin of the state space under certain circumsmnor.s. 193 A Method for Computing Optimal Controls for Mechanical Systems M.W.M.G. Dimanayake, pp 927.930 A technique for the computation of optimal controls for s class of mechanical systems is described in this pepef. It is proposed to parametrize the second derivatives of the generalized coordinates to transform the optimal control problem into a non-linearly comtmined optimization problem. This is then solved using the sequential quadratic programming method. The proposed technique is particularly suitable for mechanisms consisting of rigid links, such as industrial robots. Furthermore, continuous and terminal constraints on the state variables and controls may be easily handled. Two numerical examples illustrate the effectiveness of the proposed technique. 194 Algorithms of Time-Sub.Optimal Adaptive Control for Robot Manipulator Drives A.A. Dyda, V.F. Fllaretov, pp 931.933 This ~per develops an adaptive variable-structure system control alognthm for robotic manilmlators. At present there are many sysunns which use sliding modes in order to control complex dynamic objects. The advantages of sliding modes consist in their robusmess with respect to unmodeled dynamics and parametric uncertainties. The pmpmed adaptive control algorithm is based on the properties of-the sliding-mode parameter, and essentially improves the speed of trausient processes. The algorithm is applied to control a three-degrees-of-freedom robot manipulator. 195 LQG Control of an Hydraulic Actuator with a Flexible Mechanical Load S. Gunnareson, P. Krus, pp 935-938 This paper presents a control system based on linear quadratic state feedback and state estimation for a hydraulic actuator with a flexible mechanical load. The purpose of the control system is to improve the dynamic properties by reducing the oscillatory behavior of the load, and to eliminate the steady-state error in the load position caused by external disturbances. Using a simplified linear model, a control system is developed and evaluated using simulations and experiments. 196 Feedback Control of an Electrobydraulic Servosystem with Pressure-Dependent Uncertainties ILC. Lin, K.N. Reid, pp 939-944 An electrohydranlic servosystem has dominant nonlinearities due to the flow characteristics of the valve orifice and the pressure dependence of the hydraulic fluid bulk modulus. Feedback control design is difficult because of these nonlinearities and related uncertainties in the system parameters. A method for feedback control design is presented, using a linear model structure with signul-dopendent parameters to present the nonlinear model of the open-loop selvosystem. The method is implemented in the discrete-time domain and results in a digital controller with signaldependent gains. The resulting feedback control system is robust for a wide range of operating conditions. 197 An Approach to Modeling and Identification of Systems with Signal-Dependent Parameters ICC. LIn, K.N. Reid, pp 945.952 The identification of systems with signal-dependent parameters is considered. A method is presented which involves permneterization of the signal dependence in terms of fuzzy

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linguistic rules and iterative estimation of model parameters. The method is more robust than some previous methods for a particular set of systems. An example involving the identification of a model for an electrobydraulic servosystem is presented to demonstrate the practical application of the method. 198 Application and Design Trends of "Intelligent" Servo Pneumatics J. Pu, R. Harrison, P.R. Munre, R.H. Weston, PIP 953.958 New initiatives in designing and applying "intelligent" servo pneumatic cylinders and motors have emerged in last decade or so. However, a severe lack of confidence and knowledge still prevails in industry in the selection of servo pneumatics as am alternative to electric drive technology, particularly for advanced applications. This paper aims to promote the application and public appreciation of servo pneumatic systems. The paper reviews the inherent properties and performance capabilities of servo pneumatic chives. Applications considered to be appropriate for applying un'vo pneumatics are investigated through the analysis of a selected

exafnple.

199 Development of an Electro-Hydraulic Suspension Disc Valve Y. Sun, G.A. Parker, pp 959-965 This paper presents an electromagnetic hydraulic disc valve with a position feedback designed for vehicle semi-active suspension systems. The features of this design are that the valve has a simple structure, few critical dimensions, low manufacturing cost, and compact valve size. Although the valve is designed for a vehicle suspension system, it can be used as a two-port proportional control valve for other industrial applications, The paper deals with the theoretical model of the valve, including its static and dynamic characteristics with the disc position control, together with the experimental results.

200 Control of an Electropneumatic Servodrive: A State. Affine or a Sliding Approach D. Thomassct, E.Ricbard, S. Scavarda, X.F. Lin, S. Sesmat, A. Boubal, pp 967-970 This paper deals with two control methods applied to an electropneumatic servodrive: a state-affme control law and a sliding control. The first one replaces a set of linear control by a unique non-linear control law valid for all operating points, and the second overcomes some non-linearities. These two quite different approaches allow one to obtain a closed-loop dynamic behaviour nearly independent of the equilibrium position, as is shown by the experimental results presented.

201 Multi-lnput, Multi.Output Identification of Gain. Scheduled Lumped Parameter Models of a Pilot-Plont Climbing Film Evaporator R.M. Allen, B.R. Young, pp 971-974 The aim of this research was to investigate the modelling and control of a 25-kW, 13.6-litres/hour pilot-plant climbing film evaporator concentrating an aqueous sodium nitrate solution. This paper reports on the effectiveness of gain-scheduled linear lumped parameter models for the identification of the climbing film evaporator for the specific purpose of developing and designing industrially viable process-control systems.

202 Dispatching Rules for Manufacturing Job-Shop Operations Chen Tsiushuang, pp 975-978 This paper presents comparative results on dispatching rifles in job-shop scheduling under various shop load ratios and various due-date tightness conditions. Analysis of variance is used. Although it is impossible to identify any single rule as the best in all circumstances, P+S/OPN and the MPS rule have been identified as exhibiting good performance in general, especially MPS, in minimizing job maximum lateness.