摘要:

A major problem in designing adequate feedback controllers for physiological systems is in the large variability in the dynamics of individuals. Adaptive control schemes are considered to be suitable candidates to solve this clinical problem and, in this work, the control of muscle relaxation using a self-tuning PID control technique is investigated. The performance of this control strategy is evaluated in a real-time simulation environment, using published pharmacokinetics and pharmacodynamics of the recently introduced competitive neuromuscular blocking agent Atracurium. The sensitivity of the control algorithm with respect to simulated intra- and interindividual variability in the dynamics is studied and the feasibility of combining bolus dose and closed-loop infusion protocols of Atracurium administration is demonstrated. A series of clinical trials were undertaken where the self-tuning PID algorithm controlled successfully the delivery of Atracurium to patients undergoing surgery.

DOI:10.1049/ip-d.1990.0032

出版商:IEE    

年代:1990

数据来源: IET

摘要:

In the first paper of this series, it was shown that the least-squares solutions for the nonlinear parameters of weighted sum models, as multiexponentials, may pairwise exactly coincide. This was explained as a consequence of degeneracy of the least-squares criterion under the influence of errors. This theory is now extended to include the coincidence of more than two nonlinear parameters.

DOI:10.1049/ip-d.1990.0033

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The dynamical performance of robot manipulators is greatly affected by the different payloads handled by the end-effector (hand). Hence, it is very important, especially for industrial applications, to study the different interconnected relationships between the manipulator's joints, speeds, loads and actuation forces. In the paper, a simplified semicustomised symbolic formulation of robot dynamics, based on the Lagrangian, is presented, with emphasis on the Coriolis and centripetal effects. The accuracy and computational efficiency of this new formulation is demonstrated by simulation of the Stanford and PUMA 560 robot manipulators. Useful quantitative measurements and error analysis are also included on the significance of Coriolis and centripetal terms, under different load and speed conditions.

DOI:10.1049/ip-d.1990.0034

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The paper considers the errors arising in the direct estimation of the frequency response of linear systems, when only finite lengths of input and output records are available. Open-loop and closed-loop systems are considered. It is shown that the resultant estimates are distributed about a biased mean value. Simulation studies support the theoretical predictions.

DOI:10.1049/ip-d.1990.0035

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The paper comments on the pseudo-continuous-time quadratic regulator developed in an earlier paper. It also presents a new digital redesign technique, based on matching all the states at all the sampling instants, for finding the pseudo-continuous-time quadratic regulator.

DOI:10.1049/ip-d.1990.0036

出版商:IEE    

年代:1990

数据来源: IET

摘要:

In the paper, the problem of decentralised model-reference adaptive control, for linear time-varying large-scale systems, is investigated by using a variable-structure control approach. The global reaching condition of the sliding mode of a composite system is derived and a new scheme of decentralised control is proposed. This scheme can guarantee the stability of a sliding manifold of the composite system. Furthermore, a modified scheme is given which makes the weighted sum of the sliding manifold motions converge to the prospective speed. Finally, a numeral example is calculated.

DOI:10.1049/ip-d.1990.0037

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The paper considers the optimisation of pulse-position pulsewidth-modulated (PPPWM) control of a position servosystem. The optimisation is carried out via an equivalent PPPWM transformation of the linear optimal control law. The technique developed here is applicable to both tracking and regulator problems, and the equivalence assumes the existence of at least one pole at the origin for the plant transfer function, which is normally true for any position servosystems. The control signal is optimised with respect to the discrete quadratic performance index and a closed-loop analytical solution can be obtained. The solution for a second-order system is simple, as shown, and readily applicable to real-time sampled-data position servosystems.

DOI:10.1049/ip-d.1990.0038

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The paper develops new decentralised and hierarchical control techniques for linear interconnected, uncertain dynamical systems with additive-type bounded uncertainties. The overall system is decomposed intoNlower order subsystems, each containing uncertain elements and is corrupted by uncertain bounded disturbances. The uncertainties of the systems' parameters are known to belong to prescribed compact bounding intervals. It has been shown that, if uncertainty of the system is within a certain structure (i.e. the matching conditions hold), stabilising control always exists, no matter how large the uncertainty is. Based on this and on the theory of ultimate boundedness, the proposed decentralised and hierarchical control structures guarantee global uniform ultimate boundedness behaviour for the decomposed subsystems. Sufficient conditions are given for the stability of the global system, when driven with proposed control schemes and in the presence of interconnections with bounded uncertainties. It has been established that, with the satisfaction of these conditions and/or validity of the uncertainty matching structure, the developed decentralised and hierarchical control strategies provide robust design schemes, i.e. they are insensitive to the structural perturbations, either between the subsystems and/or in the communication network between the two-level hierarchical structure. Furthermore, the design algorithms are insensitive to parameter perturbations in their bounded ranges.

DOI:10.1049/ip-d.1990.0039

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The simultaneous ripple-free tracking problem of a prespecified class of inputs is considered. The purpose is that of providing a general and complete characterisation of all ripple-free controllers for SISO discrete systems. In the control problem treated in the paper, references are assumed to be generated by an ensemble of linear time-variant systems. Both the plant and the inputs may be unstable. By adoptintg a polynomial algebra approach, a necessary and sufficient condition is established for the existence of a causal stabilising deadbeat controller, so that the ripple free performance is attained, independent of the initial state of the plant, and for each admissible input. The proposed design procedure proves to be very simple and efficient. A detailed analysis of the least degree solution of the control problem is also presented.

DOI:10.1049/ip-d.1990.0042

出版商:IEE    

年代:1990

数据来源: IET

摘要:

The paper develops a model for a closed-loop digital control system that incorporates multirate sampling with dynamic compensation. The model completely represents system behaviour at a base sampling rate and at the integral multiple sampling rates in the system. A key feature of the model is that sampling rates can be modified conveniently, without significantly changing the structure of the model. Based on the multirate closed-loop system model, frequency-domain transfer characteristics of the system are developed. These functions are presented in such a way that the performance of different sampling regimes can be compared directly. The eigenvalues of the closed-loop system are also defined so that effects of sampling rate variation may be investigated. An example is included to illustrate use of the model

DOI:10.1049/ip-d.1990.0043

出版商:IEE    

年代:1990

数据来源: IET