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Article

Hongli Cao, Ye He, Xiaoan Chen and Xue Zhao

The purpose of this paper is to take transient contact force response, overshoots and steady-state force tracking error problems into account to form an excellent force controller.

Abstract

Purpose

The purpose of this paper is to take transient contact force response, overshoots and steady-state force tracking error problems into account to form an excellent force controller.

Design/methodology/approach

The basic impedance function with a pre-PID tuner is designed to improve the force response. A dynamic adaptive adjustment function that combines the advantages of hybrid impedance and adaptive hybrid impedance control is presented to achieve both force overshoots suppressing and tracking ability.

Findings

The introduced pre-PID tuner impedance function can achieve more than the pure impedance function in aspects of converging to the desired value and reducing the force overshoots. The performance of force overshoots suppression and force tracking error are maintained by introducing the dynamic adaptive sigma adjustment function. The simulation and experimental results both show the achieved control performance by comparing with the previous control methods.

Practical implications

The implementation of the controller is easy and convenient in practical manufacture scenes that require force control using industrial robots.

Originality/value

A superior robot controller adapting to a variety of complex tasks owing to the following characteristics: maintenance of high-accuracy position tracking capability in free-space (basic capabilities of modern industrial robots); maintenance of high speed, stability and smooth contact performance in collision stage; and presentation of high-precision force tracking capability in steady contact.

Details

Industrial Robot: the international journal of robotics research and application, vol. 47 no. 2
Type: Research Article
ISSN: 0143-991X

Keywords

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Article

Ming‐C. Cheng and Rambabu Chennupati

The concept of the evolution of the distribution function is used to derive an energy‐scale distribution that is able to describe transport phenomena, including…

Abstract

The concept of the evolution of the distribution function is used to derive an energy‐scale distribution that is able to describe transport phenomena, including inter‐valley transfer effect, in the scale as small as the energy relaxation time. The energy‐scale distribution is used to study the evolution of electrons in n‐type GaAs under the influence of rapid change in field. Results indicate that, near the peak of strong velocity overshoot or the bottom of pronounced undershoot in the Γ valley caused by the rapid change in field, the energy‐scale distribution can not respond as fast as the distribution function calculated from the Monte Carlo method. The average velocity resulting from the energy‐scale distribution therefore leads to less pronounced overshoot and undershoot than those obtained from the Monte Carlo method. However, since velocity overshoot and undershoot are not pronounced in the L‐valleys, the L‐valley energy‐scale distribution is in excellent agreement with that determined by the Monte carlo simulation.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 12 no. 4
Type: Research Article
ISSN: 0332-1649

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Article

R.K. COOK and Jeffrey FREY

A transport model has been developed which is reasonably accurate, and has proven quite efficient for the two‐dimensional numerical simulation of submicron‐scale Si and…

Abstract

A transport model has been developed which is reasonably accurate, and has proven quite efficient for the two‐dimensional numerical simulation of submicron‐scale Si and GaAs devices. In this model an approximate form of the energy‐transport equation is developed; this equation is easily included in otherwise‐conventional device simulation codes, which then require only slightly more solution time than standard models using field‐dependent transport coefficients. Calculations for 0.25 micron gate length Si and GaAs MESFET's show that velocity overshoot effects can be very important, particularly in the latter material; predicted saturation currents in the GaAs devices are almost three times larger than those that would have been predicted using conventional transport models. The model described, and its application in simulation programs, should find use in the design of submicron‐scale devices to properly take advantage of overshoot phenomena.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 1 no. 2
Type: Research Article
ISSN: 0332-1649

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Article

Stuart Thomas and Jason Potts

The purpose of this paper is to investigate a competitive evolutionary process we call “innovation overshooting” that has been observed in equipment-based sports, using…

Abstract

Purpose

The purpose of this paper is to investigate a competitive evolutionary process we call “innovation overshooting” that has been observed in equipment-based sports, using windsurfing as a case study.

Design/methodology/approach

The case-study approach is based upon primary data gathered through semi-structured, in-depth interviews with pioneers of the case-study sport and through analysis of international and domestic industry publications and grey literature.

Findings

New sports, in particular equipment-based “lifestyle” sports, can experience a rapid rise in popularity but eventually technology-driven competition leads to equipment overshooting the capabilities and financial budgets of most users. This Schumpeterian market process leads to a rapid decline in participation and the eventual collapse of the market for the sport’s equipment.

Originality/value

Models of endogenous overshooting are established in the study of finance and business cycles, and have recently been extended to the music and design industry. The authors extend this to the sports equipment sector finding clear evidence of evolutionary competitive technological and market overshooting.

Details

Sport, Business and Management: An International Journal, vol. 6 no. 5
Type: Research Article
ISSN: 2042-678X

Keywords

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Article

Ming‐C. Cheng

Influence of forward scattering, including ionized‐impurity and polar optical‐phonon scattering, on electron transport phenomena in a 3‐valley n‐type GaAs model subjected…

Abstract

Influence of forward scattering, including ionized‐impurity and polar optical‐phonon scattering, on electron transport phenomena in a 3‐valley n‐type GaAs model subjected to a rapid change in field is studied. It is shown that the macroscopic effective mass of electrons in a nonparabolic band structure is smaller than the energy‐dependent effective mass, which is usually assumed for modeling of GaAs devices, during the interval of velocity overshoot when strong forward scattering is involved. As a consequence, the hydrodynamic transport model, where the macroscopic effective mass is assumed energy dependent, leads to a smaller overshoot velocity.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 11 no. 4
Type: Research Article
ISSN: 0332-1649

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Article

Berk Gonenc and Hakan Gurocak

This paper aims to present a hybrid actuator controller to obtain fast and stiff position response without any overshoot by blending input signals of a DC servomotor and a…

Abstract

Purpose

This paper aims to present a hybrid actuator controller to obtain fast and stiff position response without any overshoot by blending input signals of a DC servomotor and a particle brake.

Design/methodology/approach

The hybrid actuator controller has a module to estimate instantaneous changes in inertia and a blending algorithm that adjusts input signals to the motor and the brake so that together, as a hybrid actuator, they can achieve a fast, stiff position response without overshoot. The control logic implemented in the controller is derived from the kinematics of the system. For the blending algorithm, two separate cases are explored in which the user has the option to either utilize the full‐braking capacity or specify a safe deceleration limit for the system.

Findings

The blending algorithm enables the system to operate nearly twice as fast as the motor‐only case without any overshoot or oscillations. The controller can reject inertial load changes and significant external disturbances.

Originality/value

Such hybrid actuators along with the developed controller can be used in robotics and automation to increase the system accuracy and operational speed resulting in higher production rates. In addition, much stiffer haptic force feedback interfaces for virtual reality applications can be designed with smaller actuators. The blending algorithm provides considerable improvements and uses a physics‐based simple and easy‐to‐implement structure.

Details

Industrial Robot: An International Journal, vol. 38 no. 5
Type: Research Article
ISSN: 0143-991X

Keywords

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Article

Brajesh Kumar Kaushik, Sankar Sarkar, R.P. Agarwal and R.C. Joshi

To analyze factors affecting crosstalk and to study the effect of repeater insertion on crosstalk, power dissipation and propagation delay.

Abstract

Purpose

To analyze factors affecting crosstalk and to study the effect of repeater insertion on crosstalk, power dissipation and propagation delay.

Design/methodology/approach

Crosstalk is effected by transition time of the signal; length of interconnect; distance between interconnects; size of driver and receiver; pattern of input; direction of flow of signal; and clock skew. This work is based on simulating interconnects with parameters obtained from 0.13 μm process. The types of noise addressed are overshoot; undershoot and oscillatory noise. Further, to study the effect of repeater insertion on crosstalk, repeaters are inserted in one line, i.e. line A only. Uniform repeaters varying in number from 1 to 60 are each of size Wn=3.9 μm and Wp=7.8 μm. Both lines A and B are terminated by a capacitive load of 5 fF. A crosstalk noise effect is measured for line A loaded with repeaters. The number of repeater is varied for four different cases of stimulations to both lines viz. input to line A, i.e. VA switching from low to high; input to line B, i.e. VB switching from low to high; input to line A i.e VA switching from low to high; input to line B, i.e. VB switching from high to low; VA switching from high to low and VB at static low; VA switching from high to low and VB at static high.

Findings

This paper shows the prominent factors such as edge rate, length and pattern of inputs affecting the noise. It is observed that presence of inductive effects can seriously hamper the functioning of the chip. This paper further reveals that repeater insertion not only reduces the propagation delay but also crosstalk levels for coupled lines. Repeaters can be efficiently utilized for reduction of propagation delay and crosstalk noise at a trade of marginal increase in power dissipation. The power‐delay‐crosstalk‐product (PDCP) criterion is introduced as an efficient technique to insert repeater in coupled interconnects. Based on PDCP a reduction in crosstalk of about 60 times and delay of 4.2 percent is achieved at trade of 13.2 percent increase in power dissipation in comparison to PDP.

Originality/value

The PDCP criterion is introduced as an efficient technique to insert repeater in coupled interconnects. Instead of PDP criterion, PDCP criterion is best suited for determination of optimum number of repeaters for overall minimization of delay, power and crosstalk.

Details

Microelectronics International, vol. 23 no. 3
Type: Research Article
ISSN: 1356-5362

Keywords

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Article

Carlos S. Betancor-Martín, J. Sosa, Juan A. Montiel-Nelson and Aurelio Vega-Martínez

Nowadays, in order to improve current applications, industry incorporates to their solution approaches artificial intelligence techniques and methodologies like Fuzzy…

Abstract

Purpose

Nowadays, in order to improve current applications, industry incorporates to their solution approaches artificial intelligence techniques and methodologies like Fuzzy Logic, neural networks and/or genetic algorithms (GA). Artificial intelligence techniques complement classical methodologies and include concepts that simulate the way humans solve problems or how processes work in nature. In this work, the Fuzzy Logic system cancels the effects of load perturbances in an energy plant, by implementing a secondary controller which complements the main controller. The purpose of this paper is to use GA to tune this new secondary controller. The authors particularize the proposal for three specific applications: control the angular speed and position of a Direct Current (DC) motor and control the output voltage of a DC/DC buck converter.

Design/methodology/approach

The authors use GA for tuning a Proportional-Integral Fuzzy Controller (PI-Fuzzy). The proposal defines a new objective function in comparison with literature approaches. The main key in the new objective function is combining the best features of Integral Square Error (ISE) function and taking out the overshoot response.

Findings

In order to demonstrate the proposed methodology based on GA tuning a PI-Fuzzy, the authors apply the literature benchmark to the solution. The results are compared with the following techniques: Robust control, continuous PID control, discrete PID control, Optimal Control, Fuzzy Control and Artificial Neural Network based control. Comparisons are presented in terms of setting time and overshot.

Originality/value

Results demonstrate that ISE or integral of absolute value of error function do not provide the desired response. Achieved results demonstrate the usefulness of the proposal to eliminate the overshoot of the traditional behaviour without lost any of the main features of the literature methodologies.

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Article

Yihui Gong, Lin Li, Shengbo Qi, Changbin Wang and Dalei Song

A novel proportional integral derivative-extended state disturbance observer-based control (PID-ESDOBC) algorithm is proposed to solve the nonlinear hydrodynamics…

Abstract

Purpose

A novel proportional integral derivative-extended state disturbance observer-based control (PID-ESDOBC) algorithm is proposed to solve the nonlinear hydrodynamics, parameters perturbation and external disturbance in yaw control of remote operated vehicles (ROVs). The effectiveness of PID-ESDOBC is verified through the experiments and the results indicate that the proposed method can effectively track the desired attitude and attenuate the external disturbance.

Design/methodology/approach

This study fully investigates the hydrodynamic model of ROVs and proposes a control-oriented hydrodynamic state space model of ROVs in yaw direction. Based on this, this study designs the PID-ESDOBC controller, whose stability is also analyzed through Kharitonov theorem and Mikhailov criterion. The conventional proportional-integral-derivative (PID) and active disturbance rejection control (ADRC) are compared with our method in our experiment.

Findings

In this paper, the authors address the nonlinear hydrodynamics, parameters perturbation and external disturbance problems of ROVs with multi-vector propulsion by using PID-ESDOBC control scheme. The advantage is that the nonlinearities and external disturbance can be estimated accurately and attenuate promptly without requiring the precise model of ROVs. Compared to PID and ADRC, both in overshoot and settling time, the improvement is 2X on average compared to conventional PID and ADRC in the pool experiment.

Research limitations/implications

The delays occurred in the control process can be solved in the future work.

Practical implications

The attitude control is a kernel problem for ROVs. A precise kinematic and dynamic model for ROVs and an advanced control system are the key factors to obtain the better maneuverability in attitude control. The PID-ESDOBC method proposed in this paper can effectively attenuate nonlinearities and external disturbance, which leads to a quick response and good tracking performance to baseline controller.

Social implications

The PID-ESDOBC algorithm proposed in this paper can be ensure the precise and fast maneuverability in attitude control of ROVs or other underwater equipment operating in the complex underwater environment. In this way, the robot can better perform undersea work and tasks.

Originality/value

The dynamics of the ROV and the nominal control model are investigated. A novel control scheme PID-ESDOBC is proposed to achieve rapidly yaw attitude tracking and effectively reject the external disturbance. The robustness of the controller is also analyzed which provides parameters tuning guidelines. The effectiveness of the proposed controller is experimental verified with a comparison by conventional PID, ADRC.

Details

Industrial Robot: the international journal of robotics research and application, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0143-991X

Keywords

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Article

Rekha Yoganathan, Jamuna Venkatesan and William Christopher I.

This paper intent to design, develop, and fabricate a robust cascaded controller based on the dual loop concept i.e. Fuzzy Sliding Mode concept in the inner loop and…

Abstract

Purpose

This paper intent to design, develop, and fabricate a robust cascaded controller based on the dual loop concept i.e. Fuzzy Sliding Mode concept in the inner loop and traditional Proportional Integral controller in the outer loop to reduce the unknown dynamics and disturbances that occur in the DC-DC Converter.

Design/methodology/approach

The proposed Fuzzy sliding mode approach combines the merits of both SMC and Fuzzy logic control. FSMC approach reduces the chattering phenomena that commonly occurs in the sliding mode control and speed up the response of the controller.

Findings

In most of the research work, the inner current loop of cascaded controller was designed by sliding mode control. In this paper FSMC is proposed and its efficacy is confirmed with SMC -PI. In most uncertainties, FSMC-PI produces null maximum peak overshoot and a very less settling time of 0.0005 sec.

Originality/value

The presence of Fuzzy SMC in the inner loop ensure satisfactory response against all uncertainties such as steady state, circuit parameter variations and sudden line and load disturbances.

Details

Circuit World, vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 0305-6120

Keywords

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