Feasibility Of Real-time Control Research Articles

Real time control of nature-based solutions: Towards Smart Solutions and Digital Twins in Rangsit Area, Thailand

The intensity and frequency of hydro-meteorological hazards have increased due to fast-growing urbanisation activities and climate change. Hybrid approaches that combine grey infrastructure and Nature-Based Solutions (NBSs) have been applied as an adaptive and resilient strategy to cope with climate change uncertainties and incorporate other co-benefits. This research aims to investigate the feasibility of Real Time Control (RTC) for NBS operation in order to reduce flooding and improve their effectiveness. The study area is the irrigation and drainage system of the Rangsit Area in Thailand. The results show that during the normal flood events, the RTC system effectively reduces water level at the Western Raphiphat Canal Station compared to the system without RTC or with additional storage. Moreover, the RTC system facilitates achieving the required minimum volume and increasing the volume in the retentions. These findings highlight the potential of using RTC to improve the irrigation and drainage system operation as well as NBS implementation to reduce flooding. The RTC system can also assists in equitable water distribution between Klongs and retention areas, while also increasing the water storage in the retention areas. This additional water storage can be utilized for agricultural purposes, providing further benefits. These results represent an essential starting point for the development of Smart Solutions and Digital Twins in utilizing Real-Time Control for flood reduction and water allocation in the Rangsit Area in Thailand.

Real-time control for at-limit handling driving on a predefined path

ABSTRACTAutonomous driving at at-limit handling represents a big challenge due to the nonlinear behaviour of a vehicle. In this paper, a hierarchical control scheme composed of two Nonlinear Model Predictive Controls (NMPCs) for path following is proposed. This structure allows for real-time feasibility without having to simplify excessively the vehicle model. The higher level NMPC operates on a long prediction horizon with a point-mass model which constraints are given by a tyre dependant ‘g–g diagram’. The output of the higher level is a velocity profile which is used as terminal constraint by the lower level NMPC. This operates on a short horizon and is based on a seven degrees of freedom vehicle model with full Pacejka Magic Formula tyre formulation on all tyres, load transfers and Limited Slip Differential. Because of the terminal set computed by the higher level, it is possible to use a short horizon and exploit the vehicle performance in real-time. For both controllers, the full Nonlinear Optimisation Problem is solved at each step. The algorithm is tested in a Model-in-the-Loop environment where a validated Vi-Grade vehicle model is controlled in co-simulation. The results show the effectiveness and feasibility of real-time control with complex vehicle models.

A feasibility study on process monitoring and control in vat photopolymerization of ceramics

Vat photopolymerization is a prominent additive manufacturing technology for the fabrication of near-net shape ceramic parts. To serve the high tech industry’s needs, additive manufacturing equipment has to scale up to larger product sizes and higher, repeatable product quality. This motivates the integration of more process monitoring and control solutions into the equipment. Hence, this paper reviews the state of the art in process modelling, sensing, actuation and control for ceramic vat photopolymerization. The aim is to analyze the feasibility of potential real-time control schemes for the vat photopolymerization process. A comparison of time scales related to physical phenomena in vat photopolymerization, sampling rates of sensors, and response times of actuators, shows that feasibility of real-time control is governed by sensor sampling rates. With the current state of sensor technology, real-time control is only feasible in mask projection systems. Alternatively, one can resort to layer-to-layer control schemes.

Optimal control of a flexible parallel link robotic manipulator

The parallel link robotic manipulator consists of a base platform fixed in space or attached to the end-effector of another robot, a mobile platform, and six linear actuators (pistons) that link the two platforms together. The load carrying parts of the actuators are considered to be flexible (deformable) and modeled as mass-spring-damper elements. The nonlinear dynamic equations of the manipulator have been rigorously derived. No attempt has been made to linearize the plant or the measurements. The observer and the control law are derived based on the optimal control theory. The control gain matrix and the estimate gain matrix are obtained by solving the algebraic Riccati equations. The state excitation white noises and the observation white noises are included in the plant and the measurements, respectively. The dynamic equations of the observer are solved analytically and exactly. The feasibility of real-time control is demonstrated by the computer simulation results which are presented here.