Synthesis of a nonlinear control system

Flügge‐Lotz, I.; Taylor, Carrie-Anne

doi:10.1109/tac.1956.1100823

Cited by 15 publications

(6 citation statements)

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“…Their objective was improving control-system performance, i.e., achieving shorter settling times and reducing overshooting, than achievable using a single linear controller only. Flügge-Lotz was one of the first to investigate such systems, and she and Taylor expressed their intention in the following sentence that remains valid to this day: "The decision to introduce nonlinear components in a control system may stem from the desire to have a system whose performance is less tied to history than that of linear control systems of comparable power handling" (Flügge-Lotz & Taylor, 1956). Beyond some early work (Bilharz, 1941;Flügge-Lotz & Klotter, 1943, typical examples of the basic ideas developed over that period may be found in, e.g., (McDonald, 1950;Flügge-Lotz, 1953;Flügge-Lotz & Wunsch, 1955;Flügge-Lotz & Taylor, 1956;Ostrovsky 1960).…”

Section: Early Discontinuous Controlsmentioning

confidence: 99%

“…Flügge-Lotz was one of the first to investigate such systems, and she and Taylor expressed their intention in the following sentence that remains valid to this day: "The decision to introduce nonlinear components in a control system may stem from the desire to have a system whose performance is less tied to history than that of linear control systems of comparable power handling" (Flügge-Lotz & Taylor, 1956). Beyond some early work (Bilharz, 1941;Flügge-Lotz & Klotter, 1943, typical examples of the basic ideas developed over that period may be found in, e.g., (McDonald, 1950;Flügge-Lotz, 1953;Flügge-Lotz & Wunsch, 1955;Flügge-Lotz & Taylor, 1956;Ostrovsky 1960). The ideas of this first development phase were seminal for succeeding methods in control theory: (1) an early contribution towards adaptive control known as "dualmode control" (McDonald, 1952), (2) time-optimal control, accompanied by initial important results, in (Bushaw, 1952(Bushaw, , 1953Fel'dbaum, 1953), and (3) suboptimal VSC lacking sliding modes aimed at achieving short settling times (Kiendl, 1972;Becker, 1979).…”

Section: Early Discontinuous Controlsmentioning

confidence: 99%

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Soft variable-structure controls: a survey

2004

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Variable-structure controls are normally understood to be controls that have sliding modes and robustness as their main objective. In addition to sliding-mode controls, there are also variable-structure controls, which were developed for the purpose of intentionally precluding sliding modes and achieving high regulation rates and short settling times. Two types of such controls may be distinguished, variable-structure controls that switch between different parameters and a systematic further development of them called "soft variable-structure controls" that continuously vary controllers' parameters or structures and achieve nearly time-optimal control performance. This paper surveys soft variable-structure controls, compares them to other controls, taking a submarine dive-control as an example, and presents an outlook on their auspicious further development.

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Section: Early Discontinuous Controlsmentioning

confidence: 99%

Section: Early Discontinuous Controlsmentioning

confidence: 99%

Soft variable-structure controls: a survey

2004

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“…4 can be used to model a single button, but what if there is more than one button, as is the case with a chevron-key interface? As part of their work on developing the theory behind relay controllers, Flügge-Lotz and Taylor [56] created a discontinuous controller that can switch between four discrete levels, as shown in Fig. 5.…”

Section: A Modeling Continuous Behaviormentioning

confidence: 99%

“…In order to represent four discrete values, we make use of a switching criterion incorporating two signum functions as defined by Flügge-Lotz and Taylor [56]:…”

Section: A Modeling Continuous Behaviormentioning

confidence: 99%

A Human Operator Model for Medical Device Interaction Using Behavior-Based Hybrid Automata

Niezen

Eslambolchilar

2016

IEEE Trans. Human-Mach. Syst.

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This paper describes the design and implementation of a control-theoretic model that can be used to model both the discrete and continuous behavior of a human operator. The human operator model can be used to compare different device user interfaces in terms of human performance. The implemented human operator model combines an ON-OFF control model and a behavior-based hybrid automaton with three controllers. The controllers, defined as continuous, discrete, and fine-tuning behavior, simulate the user's conceptual model of the user interface. The device model used is that of a commercial syringe pump with chevron keys, described as a formal specification. Results of the human operator model simulation were generated for 20 different numbers obtained from syringe pump log files. The simulation results were compared over 33 trials to a lab study employing a device based on the formal specification. The result of the simulation shows a significant similarity to the result of the lab study for all the numbers used.

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“…Parallel valve systems have been studied at Tampere University of Technology: there is indeed an analogy with the electronic system proposed by Flu¨gge-Lotz and Taylor. 9 Both systems utilize a Boolean logic operating system in which multiple, parallel-operated actuators, with different gains can be switched in different logic combinations. In the Forward Look article, the authors claim that these combined valves can be manufactured at a lower cost than proportional valves.They also state: ''switching valves have the potential to become very compact and light components''.…”

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confidence: 99%

Discussion: Is the future of fluid power digital?

Achten¹,

Linjama

Scheidl

et al. 2012

Proceedings of the Institution of Mechanical Engineers, Part I:

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Imagine the scenario in which an electric motor company came to the (correct) conclusion that the power density of hydraulic pumps and motors is much higher than that of electric generators and motors. Then imagine that the board of this company gave the (wrong) instruction to the R&D department to utilize the concept of hydrostatic machines to develop electric generators and pumps with the same power density as their hydraulic equivalents.The reasoning of the board parallels the reasoning of the Forward Look article 1 in which Rudolf Scheidl, Matti Linjama and Stefan Schmidt argue that the future of fluid power will become partly digital: ''The overwhelming success of digital concepts in information, communication and power electronics, as well as the analogy between electrical and fluid power systems, suggest that digital concepts should be beneficial in fluid power''. Or, to recast this statement: ''The overwhelming success of feathers for making birds fly, as well as the analogy between birds and fish, suggests that feathers should also be beneficial for fish''. In addition the authors emphasize that ''the positive connotations of the word 'Digital' are good selling points''.Do not be mistaken! I am a strong supporter of research in digital hydraulic systems, although I am not at all convinced that the future of fluid power will be digital. To quote Einstein: ''If at first, the idea is not absurd, then there is no hope for it.'' A lot of research in digital fluid power I consider to fall in the category 'absurd', in the sense of 'out of tune' or 'dissonant' with the ruling technology, and I am very curious to see what will be useful in the end.The idea to copy successful electrical concepts in the design of hydraulic systems and components is as old as the hydraulic industry itself. Examples are 'fluidics' or 'fluidic logics' in which a fluid flow is directed in order to perform analog or digital operations, similar to electronic devices. 2 The authors of the Forward Look article refer to another example, AC hydraulics, in which the principle of a three-phase a.c. network is converted to a three-phase alternating flow network. 3,4 Other examples are 'switched reactance hydraulics' 5 and 'PWM electrohydraulic control systems'. 6 Aside from some niche applications, none of these promising developments has been applied successfully in the market.In 2011, Linjama presented an overview of the stateof-the-art of digital fluid power. 7 In that article he

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Synthesis of a nonlinear control system

Cited by 15 publications

References 0 publications

Soft variable-structure controls: a survey

Soft variable-structure controls: a survey

A Human Operator Model for Medical Device Interaction Using Behavior-Based Hybrid Automata

Discussion: Is the future of fluid power digital?

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