Non-adaptive Case Research Articles

Design of restricted complexity digital regulators using explicit criterion minimisation

This paper describes a technique for designing digital regulators when their structure is restricted. A new formula is first derived for computing quadratic performance indices, which indicates that, rather than using iterative algorithms or residue calculus which may be difficult to apply for high-order systems, the problem reduces to solving certain Diophantine equations. Furthermore, gradients of the performance indices, which are needed in any algorithm for updating the controller parameters, can also be easily computed using similar equations. Based on this, we present a minimisation algorithm for tuning the controller parameters. Design of restricted complexity adaptive regulators used in controlling systems subjected to random noise is also given. Because of the importance of PID controllers, we show briefly how the method is applied to their tuning. Several examples for designing the controllers in both the adaptive and nonadaptive cases are given to demonstrate the feasibility of the proposed method and its merits.

Adaptive control of constrained Markov chains: Criteria and policies

We consider the constrained optimization of a finite-state, finite action Markov chain. In the adaptive problem, the transition probabilities are assumed to be unknown, and no prior distribution on their values is given. We consider constrained optimization problems in terms of several cost criteria which are asymptotic in nature. For these criteria we show that it is possible to achieve the same optimal cost as in the non-adaptive case.

An algorithm for multirate sampling adaptive control

A stable multirate sampling adaptive control algorithm is presented which enables the fast sampling rate to be applied in closed-loop feedback control. The sampling rate is only restricted by the time needed for the control law computation (as in the nonadaptive control case) plus the estimation error computation. The plant input and output are recorded prior to the currently obtained estimate and used to compute the coming estimate and controller coefficients. Thus, the computation is not dependent upon the inputs and outputs appearing during the updating process. The closed-loop system is shown to be stable. >

A Two-Channel Picture Coding System: II--Adaptive Companding and Color Coding

The two-channel picture coding system previously reported is improved by adaptive companding and extended to component color coding. The basic system divides the spectrum into lowand high-frequency spatial components. The former are coarsely sampled and finely quantized, while the latter are finely sampled and coarsely quantized using a companded, randomized quantizer. The adaptive version uses a companding factor, larger than one, which multiplies the highs before coding and divides the result after decoding. This substantially raises the signal-to-noise ratio, which is calculated for both the adaptive and nonadaptive cases and confirmed by computer simulation. The color version uses an achromatic highs channel as in the basic monochrome system, plus a three-color lows channel coded in a perceptually uniform color space. With 3.5-4.3 bits/pel for 512 × 512 monochrome and color still images, the nonstatistical version produces images free of visible defects under normal viewing conditions. Projections are made for system parameters capable of achieving the very high quality now being proposed for production component coding systems, but with substantial reduction in channel capacity.

On adaptive stabilization of programed motions of mechanical systems: PMM vol. 41, n≗ 5, 1977, pp. 859–869

The problem of stabilizing programed motions of mechanical systems with holonomic and nonholonomic relationships is considered for various degrees of information about parameters of the equation of motion. First, the laws of control that stabilize programed motions in the nonadaptive case when parameters of the equation of motion are known and the initial perturbations are arbitrary, are synthesized. The adaptive control is constructed on that basis; such control ensures after the transitional process of adaption the closeness of the actual and programed motions. Solution of the adaption problem is based on the method of finite-convergent algorithms for solving systems of inequalities proposed in [1], Estimates of the time taken by the transitional process are presented for the adaptive and nonadaptive cases. Application of proposed algorithms for adaptive stabilization of programed motions of a transport robot on a caterpillar undercarriage and of a robot manipulator is discussed [2–5]