Sequence Of Control Signals Research Articles

Improvement of Acceleration Tracking accuracy of Electrohydraulic Vibration Testing Machine

A new control technique is proposed to realize accurate acceleration tracking for repetitive desired acceleration waveforms in an electrohydraulic vibration testing machine. In the proposed algorithm for iterative waveform reformation, the control signal sequence for next operation is determined by utilizing the information of the frequency-response function of the servo mechanism as well as the tracking error obtained from the past operations. It is theoretically clarified first that the stability limit of the iterative reforming process and the convergence speed of the tracking error are predominantly decided by the estimation accuracy of the frequency-response function. Experiments show that nearly perfect tracking can be achieved by using the proposed technique for iterative waveform reformation utilizing the adaptively estimated information of the frequency-response function regardless of kinds of desired waveforms even under operating conditions subjected to inherent highly nonlinearities.

State reachability analysis of fuzzy models

For a discrete-time system modeled by fuzzy implications, a state x f is reachable from another state x 0 if there exists a sequence of control signals to drive the fuzzy model from x 0 to x f at some final time instant. It will be shown that if the product-operation rule, the exponential shape membership functions, and the center-of-area defuzzification method are used, then the state reachability problem of fuzzy models can be resolved by solving a sequence of nonlinear programming problems. If the objective function of any of the nonlinear programming problems is found to be zero, then the state x f is reachable from the state x 0 and the corresponding control signals can be determined. Otherwise, x f is unreachable from x 0 and there exists no control signals to drive the fuzzy model from x 0 to x f .

Automated synthesis of microprogrammed controllers in digital systems

The paper presents an integrated procedure, called MCS, for the automated synthesis of microprogrammed controllers in digital systems at the register-transfer (RT) level. To MCS there are two major inputs: a description of the data path of the digital system and a behavioural description of the digital system at the RT level. The result given by MCS is a cost effective controller which can drive the operations of the data path. MCS works in seven major steps: (a) Defining an initial basic controller model; (b) generating sequences of control signals; (c) manipulating control-flow statements; (d) compacting parallel operations; (e) determining the lower bound of control word width; (f) determining the control word format; (g) encoding the control memory. The algorithms that MCS uses in carrying out these steps are described. The paper also describes two experiments in which the MCS is used to synthesise the controllers of two small hypothetical CPUs.

Microprogramming implementation of timed Petri nets

This paper describes a method to implement restricted timed Petri nets by microprograms. These timed Petri nets are used to represent control parts of VLSI systems to produce sequences of control signals that evoke the operations of a corresponding data part. The proposed method consists of a set of transformation algorithms which have been implemented as parts of CAMAD, an integrated design aid system. We have also studied the problem of microprogram optimization, for example, how to reconstruct the control structure of a VLSI system so as to produce better microprograms.

Synthesis of control structures from Petri net descriptions

A methodology to automate the design of control structures for VLSI systems is described. These control structures are modelled as timed Petri nets with restricted transition firing rules. They produce sequences of control signals to evoke operations of their associated data parts. A control Petri net together with its corresponding data part forms the design representation which has been utilized in the synthesis of VLSI systems from their high level behavioral descriptions. As part of this synthesis package, a set of algorithms and optimization strategies have been developed to transform such a restructed timed Petri net into microprograms.

Development tools for bit-slice microprocessors

This paper describes a method to implement restricted timed Petri nets by microprograms. These timed Petri nets are used to represent control parts of VLSI systems to produce sequences of control signals that evoke the operations of a corresponding data part. The proposed method consists of a set of transformation algorithms which have been implemented as parts of CAMAD, an integrated design aid system. We have also studied the problem of microprogram optimization, for example, how to reconstruct the control structure of a VLSI system so as to produce better microprograms.

On the Equivalence of Asynchronous Control Structures

This paper is concerned with the problem of detecting when two asynchronous control systems are equivalent. The systems investigated in the paper are first represented by means of a formal model called an asynchronous control structure (ACS). This model specifies the constraints imposed on the generation of control signals by a system by means of a simple graphical model called a marked graph. Behavioral equivalence is then characterized in terms of the set of all possible sequences of control signals that can be generated by the system. These sequences are represented by means of another (infinite) marked graph, called a behavior graph. Finally, it is shown that two control systems are equivalent if and only if their behavior graph representations have identical (finite) generating sets.

Time-optimal control of sampled data systems in the frequency domain†

The usual design problem is to determine a control signal sequence which operates on a plant to meet certain prescribed design specifications or performance criteria. The concept of controllability and observability play an important role in time-optimal control systems. In most of the cases, although the problem is given in the frequency domain, it is usual to convert it into the time domain for determining the optimal control sequence. It is shown in this paper that such a procedure is unnecessary and that the entire design for time-optimal performance can be carried out in the frequency domain itself.

An algorithm for stochastic control through dynamic programming techniques

An algorithm based on the concept of state and dynamic programming is derived for designing an optimum controller for a linear plant subject to noise. The controller is optimal in the sense that the behavior of the plant satisfies the expected mean quadratic performance index (EMQPI) defined in the paper. The algorithm generates the sequence of control signals which minimize the EMQPI. In addition, it gives the minimum of the EMQPI for the specified sequence of control signals. The control signal is found to consist of two components: 1) a linear combination of the system state variables, and 2) a noise-balance component which minimizes the noise-induced deviation of the actual plant output from the desired output. An example is given to illustrate the iterative procedure and the asymptotic behavior of the algorithm. The design is optimal for a class of system inputs, and is applicable to both sampling and continuous systems. The design procedure is developed to make full use of a digital computer. The basic principles of dynamic programming to the treatment of stochastic control processes are clearly illustrated in an introductory form so that it will be of interest to control engineers who may wish to familiarize themselves with dynamic programming techniques.