Search results

The purpose of this paper is to present powered‐wheelchair transducers and systems that provide more control, reduced veer on slopes, and improved energy conservation, while reducing effort. They are especially significant for people with movement disorders who lack sufficient hand‐grasp and release ability or sufficient targeting skill to use joysticks.

Laboratory test rigs are created to test proportional switches and teach potential users. Then, trials are conducted with a rolling road and in real situations. Caster angle‐measurement is selected to provide feedback to minimize drift away from a chosen course and an electronic solution was created to match driver control to caster‐steering‐position. A case study is described as an example.

Results and advantages are presented from changing from using a set of digital‐switches to a set of new variable‐switches and then adding a sensor system to prevent veer on slopes. Systems have been tested for nearly two years and shown to assist powered‐wheelchair‐users with poor targeting skills.

The research used wheelchairs with caster‐wheels but the systems could easily be used on other wheelchairs.

Simple input‐devices are presented that isolate gross motor function and are tolerant to involuntary movements (proportional‐switches). A sensor system is presented that assists users in steering across sloping or uneven ground.

Proportional‐switches and sensors are shown to reduce veer and provide more control over turn and forward speed and turn radius while reducing frustration and improving energy conservation. The simple and affordable systems could be created and attached to many standard powered‐wheelchairs in many organisations.

The purpose of this paper is to propose a new framework based on linear control system theory and the use of proportional (P) controller and proportional integral (PI) controller to address identified stability issues and control the time properties in hybrid fire testing.

The paper approaches hybrid fire testing as a control problem. It establishes the state equation to give the general stability conditions. Then, it shows how P and PI controllers can be incorporated in the system to maintain stability. A virtual hybrid fire testing is performed on a 2D steel frame for validation and to compare the performance of the controllers.

Control system theory provides an efficient framework for hybrid fire testing and rigorously formulate the stability conditions of the system. The use of a P-controller stabilises the process, but this controller is not suitable for continuous change of stiffness of the substructures. In contrast, a PI-controller handle the stiffness changes. The results of a virtual hybrid fire testing of a 2D steel frame shows that the PI-controller succeeds in reproducing the global behaviour of the frame, even if the surrounding structure is non-linear and subjected to fire.

The paper provides a rigorous formulation of the general problem of hybrid fire testing and shows the interest of a PI controller to control the process under varying stiffness. This methodology is a step forward for hybrid fire testing because it allows capturing the global behaviour of a structure, including where the numerical substructure behaves nonlinearly and is subjected to fire.

The purpose of this paper is to propose and validate a robust industrial control system. The aim is to design a Multivariable Proportional Integral controller that accommodates multiple responses while considering the process's control and noise parameters. In addition, this paper intended to develop a multidisciplinary approach by combining computational science, control engineering and statistical methodologies to ensure a resilient process with the best use of available resources.

Taguchi's robust design methodology and multi-response optimisation approaches are adopted to meet the research aims. Two-Input-Two-Output transfer function model of the distillation column system is investigated. In designing the control system, the Steady State Gain Matrix and process factors such as time constant (t) and time delay (?) are also used. The unique methodology is implemented and validated using the pilot plant's distillation column. To determine the robustness of the proposed control system, a simulation study, statistical analysis and real-time experimentation are conducted. In addition, the outcomes are compared to different control algorithms.

Research indicates that integral control parameters (K_i) affect outputs substantially more than proportional control parameters (K_p). The results of this paper show that control and noise parameters must be considered to make the control system robust. In addition, Taguchi's approach, in conjunction with multi-response optimisation, ensures robust controller design with optimal use of resources. Eventually, this research shows that the best outcomes for all the performance indices are achieved when Kp11 = 1.6859, Kp12 = −2.061, Kp21 = 3.1846, Kp22 = −1.2176, Ki11 = 1.0628, Ki12 = −1.2989, Ki21 = 2.454 and Ki22 = −0.7676.

This paper provides a step-by-step strategy for designing and validating a multi-response control system that accommodates controllable and uncontrollable parameters (noise parameters). The methodology can be used in any industrial Multi-Input-Multi-Output system to ensure process robustness. In addition, this paper proposes a multidisciplinary approach to industrial controller design that academics and industry can refine and improve.

The purpose of this paper is to perform an indoor autonomous flight of ornithopter using a novel motion capture system.

The ornithopter platform has no on‐board sensors and processors for state estimation or feedback control. Instead, passive markers on the ornithopter body reflect IR light of the multiple strobing CCD cameras, and the position data of the markers are streamed to the ground station in almost real time. Control inputs such as wingbeat frequency and rudder angle are generated by the proportional feedback controllers which are implemented in the ground station and transmitted to the ornithopter. Due to the complexity and nonlinearity of aerodynamics and flexible multibody dynamics, the flight dynamics of ornithopter are difficult to realize in the closed form of state‐space system equations. A controller for stabilizing the flight state variables of ornithopter is not necessary to be implemented by means of flapping counter‐forces and torques which make ornithopter have inherent flight stability. The gains of controllers for following circular trajectories are obtained by a trial‐and‐error approach rather than a model‐based design.

The autonomous ornithopter successfully circulates the pre‐described radius with the constant altitude and the result shows that control strategies proposed in this study are sufficient to implement the autonomy of ornithopter flight.

The autonomous flight of ornithopter is firstly conducted in a confined indoor environment by using the motion capture system and the control performance is evaluated in terms of position errors.

This paper aims to examine a congestion situation of a certain type of restaurant in a theme park (Tokyo Disney Resort) by a simulation based on Little’s law, which is a basic principle in Queueing theory. In the restaurant, a guest (customer) lines up to order, pay and receive dishes. A problem is that even when a guest can easily find vacant tables, it takes a long time to receive dishes. Because guests can see there are vacant tables, there are many tweets of complaints. This situation is a factor to undermine customer satisfaction.

This paper proposes dedicated special menu lines only providing special set as one solution that can be realized at a low cost to reduce vacant tables. Here, if the number of special menu lines is fixed, the difference between a queue in regular lines and that in special menu lines will be big. To shorten the difference, the author proposes a technique to regulate by using feedback control (Proportional control or Fuzzy control).

The simulation result shows that the number of vacant tables decreases by about 16 per cent compared with the current situation.

This paper considers a specific restaurant, but the proposed method can be applied to the same type of restaurant in the theme park. If the restaurant in the theme park is crowded, the feedback control of the queue brings new possibilities.

本论文旨在检验主题公园（日本迪士尼）内饭店的拥堵情境。本论文采用同步模拟的方式，以等候理论的基础原则—科特尔法则为基础，来进行检验。在一家饭店中，客人（顾客）排队点餐、付款、以及拿到食物。其中问题是，即使客人能够轻松找到空桌位，而等餐的时间非常长。因为客人看到有空桌位，所以客人会有很多抱怨。这种情境会严重影响顾客满意度。

本论文提出一种特别菜单行数设计来用低成本的方式解决空桌位的问题。如果特别菜单行数是固定的，那么使用常规菜单和特别菜单所产生的排队现象会大有不同。本论文借助反馈控制（比例控制或模糊控制），提供一种调节方法以减少这种差别。

模拟结果表明空桌位的数量同现有情境相比，减少了16%.

本论文采用特定的饭店，但是提出的方法可以推广到同种类型的主题公园饭店。如果主题公园饭店人满为患，那么使用反馈控制来调价排队情况将带来新可能。

主题公园、饭店、等候理论、科特尔法则、模糊控制、比例控制

Nowadays, e‐queues are built up everywhere where customer online service is necessary such as in banks' e‐service, enterprises' e‐business, etc. In order to enhance quality of service (QoS), active queue management (AQM) algorithms are frequently employed due to their efficiency in congestion avoidance as well as the differentiated forwarding of packets. This paper aims at developing a novel AQM algorithm to better QoS in terms of congestion prediction, queuing delay, packet loss and link utility, etc.

Upon the traditional designs of AQM, this paper establishes a new integrated AQM scheme (RQ‐AQM) by employing input rate and current queue length to calculate the packet dropping/marking probability. In this way, the rate feedback control enables to rapid response to congestion, decreasing the packet loss from buffer overflow. Meanwhile, the queue length feedback control stabilizes the queue length around a given target, achieving predictable queuing delay and lower delay jitter. Thus, the main feature of the design is to use coefficients of both proportional rate control and proportional‐integral queue length control, and to simplify parameter setting, the control parameters were scaled by the link capacity C to normalize the rate and by the bandwidth‐delay product BDP to normalize the queue length, respectively.

The stability performance of RQ‐AQM was tested via simulation under several conditions. The results proved that it is able to maintain the queue length around the given target. Also, the comparison results with other AQM schemes, including RED, ARED, PI controller, AVQ and REM, demonstrated the superiority of RQ‐AQM in low packet loss, faster convergence to target queue length and closest to the target queue length.

The main limitation of this study is that all the simulations were merely under a single bottleneck network topology. Furthermore, the system stability was examined under just a few cases. Other cases like TCP connections mixed with HTTP connections, or UDP flows, etc. can also be tested. Furthermore, the multiple bottleneck scenarios should be covered in the future work with more parameters set to enhance the proved results.

The paper sets clear but ideal conditions for the performance of proposed algorithm; so the simulation results can only be used as a rough reference instead of an exact practical one. But the concepts the paper attempted to advocate could be considered seriously.

The scope of the paper is within the general theory of AQM. So it can be referred to any specific field that employs AQM technology, no matter locally or globally.

There are not much new brand contents in the paper. The main contribution is on some extension of the known related work.

The purpose of this paper is to develop and compare conventional and neural network-based controllers for gas turbines.

Design of two different controllers is considered. These controllers consist of a NARMA-L2 which is an artificial neural network-based nonlinear autoregressive moving average (NARMA) controller with feedback linearization, and a conventional proportional-integrator-derivative (PID) controller for a low-power aero gas turbine. They are briefly described and their parameters are adjusted and tuned in Simulink-MATLAB environment according to the requirement of the gas turbine system and the control objectives. For this purpose, Simulink and neural network-based modelling is used. Performances of the controllers are explored and compared on the base of design criteria and performance indices.

It is shown that NARMA-L2, as a neural network-based controller, has a superior performance to PID controller.

This study aims at using artificial intelligence in gas turbine control systems.

This paper provides a novel methodology for control of gas turbines.

The purpose of this paper is to apply the proportional integral (PI) control algorithm in discrete manufacturing enterprises to maintain lower and steadier work in progress so as to improve on‐time delivery.

A sensitivity constrained optimization model is designed on the frequency domain, whose optimum algebraic solutions are then obtained easily. Two controllers, a backlog controller and an input‐rate controller, are devised, which correspond to the integral control and the proportional control of PI controllers, respectively. Interacting with each other, these controllers have made the engineering implementation of PI controllers a reality.

Simulation is carried out in certain motorcycle production lines. Results confirm that PI controllers also possess good control effects in the discrete manufacturing industry, as well as in the process industry.

A continued departure from the nominal may happen repeatedly if the root causes of changing are not detected and identified. Moreover, PI controllers can mask process defects, failures, and drifts, and this may lead to eventual catastrophic failures. So, statistical process control should be utilized in PI controlled processes to detect significant changes for long‐term process improvement.

PI controllers possess potential in discrete enterprises.

PI controllers are tried for process improvement in discrete manufacturing enterprises.

In recent years, use of sensorless control methods for electrical motor-based variable speed drive systems has been increasing rapidly to compensate the increasing costs in industrial systems. Also, use of induction motors is popular for a long time to decrease the cost of these industrial systems. This study aims to design an effective controller to improve the sensorless speed control performance of induction motor. To achieve this, a conformable fractional order proportional integral (CFOPI) controller is designed.

The system is modeled based on small signal analysis by using the input–output data, experimentally. To do this, system identification toolbox of Matlab is used. The proposed controller is established on conformable fractional integral approach proposed by Khalil et al. (2014). CFOPI controller coefficients are optimized using particle swarm optimization method on the created small signal-based simulation model of the system to minimize the integral time absolute error. To prove the success of the proposed method, a traditional fractional order proportional integral (TFOPI) controller is tested under the same experimental system with the CFOPI controller.

TFOPI and CFOPI controllers are tested with the optimum parameters. Reference and actual speed trends are obtained for both methods. In induction motor start-up test, settling-times are measured as 8.73 and 8.44 s and steady-state oscillations are 2.66% and 0% (almost) for TFOPI and CFOPI controllers, respectively. In variable referenced speed tracking test, CFOPI performs well at all speed levels, while TFOPI fails to reach the reference speed at most speed levels.

Proposed CFOPI control method can be easily implemented in industrial systems, thanks to its simple algorithm. digital signal peripheral interface controller (dsPIC) based driver circuit with designed CFOPI controller used in this study can be applied directly to industrial systems such as elevators, conveyors, cranes and drills. Moreover, it can improve the performance of induction motor-based variable speed drive systems.

The proposed method provides robust performance for induction motor used in control systems. Additionally, it does this by using less complex algorithm written on the processors according to the traditional fractional order controllers.

To gain accurate support for large aircraft structures by ball joints in aircraft digital assembly, this paper aims to propose a novel approach based on visual servoing such that the positioner’s ball-socket can automatically and adaptively approach the ball-head fixed on the aircraft structures.

Image moments of circular marker labeled on the ball-head are selected as visual features to control the three translational degrees of freedom (DOFs) of the positioner, where the composite Jacobian matrix is full rank. Kalman–Bucy filter is adopted for its online estimation, which makes the control scheme more flexible without system calibration. A combination of proportional control with sliding mode control is proposed to improve the system stability and compensate uncertainties of the system.

The ball-socket can accurately and smoothly reach its desired position in a finite time (50 s). Positional deviations between the spherical centers of ball-head and ball-socket in the X-Y plane can be controlled within 0.05 mm which meets the design requirement.

The proposed approach has been integrated into the pose alignment system. It has shown great potential to be widely applied in the leading support for large aircraft structures in aircraft digital assembly.

An adaptive approach for accurate support of large aircraft structures is proposed, which possesses characteristics of high precision, high efficiency and excellent stability.