Parametric optimization of a steering system based on dynamic constraints collaborative optimization method

The power systems of the future - smart grid - will see an increase in both renewable energy sources and load demand increasing the need for fast dynamic reconfiguration of system parameters. Advanced simulation capabilities are needed to support future planning and to implement real-time dynamic optimization. To achieve this, intelligent algorithms are needed for prediction and system monitoring along with advanced hardware to provide speed. FASTSIM capabilities allows for fast prediction of how a proposed reconfiguration will affect the system permitting implementation of radical reconfigurations without fear of disturbing vital system settings since the proposed solution will be checked before being implemented. Power systems will need to be continuously monitored for power losses and system contingencies. A combination of system states prediction, dynamic load flow, system optimization, and solution stability checking will allow for a more reliable, affordable and clean power grid. This paper presents a dynamic optimization method based on adaptive critic designs for the smart grid environment.

Dynamic optimization of electromechanical coupling system is a significant engineering problem in the field of mechatronics. The performance improvement of electromechanical equipment depends on the system design parameters. Aiming at the spindle unit of refitted machine tool for solid rocket,the vibration acceleration of tool is taken as objective function,and the electromechanical system design parameters are appointed as design variables. Dynamic optimization model is set up by adopting Lagrange-Maxwell equations,Park transform and electromechanical system energy equations. In the procedure of seeking high efficient optimization method,exponential function is adopted to be the weight function of particle swarm optimization algorithm. Exponential inertia weight particle swarm algorithm(EPSA),is formed and applied to solve the dynamic optimization problem of electromechanical system. The probability density function of EPSA is presented and used to perform convergence analysis. After calculation,the optimized design parameters of the spindle unit are obtained in limited time period. The vibration acceleration of the tool has been decreased greatly by the optimized design parameters. The research job in the paper reveals that the problem of dynamic optimization of electromechanical system can be solved by the method of combining system dynamic analysis with reformed swarm particle optimization. Such kind of method can be applied in the design of robots,NC machine,and other electromechanical equipments.

This paper presents position tracking control of an electronically actuated Pitman Arm steering system. A validation method, Model-in-the-Loop Simulation (MILS) is used to investigate the capability of Pitman Arm steering system and model. The MILS is divided into two types of method known as Software-in-the-loop Simulation (SILS) using mathematical derivation based on Lagrange theory and Hardware-in-the-Loop Simulation (HILS) using actual Pitman Arm steering system. A steering test rig is developed for HILS testing using real Pitman Arm steering mechanism. The test rig is experimented using National Instrument data acquisition system, xPC Target and Host PC, electronic control unit to study the behavior of the Pitman Arm steering system. The behavior of Pitman arm steering mechanism is evaluated based lateral input of armored vehicle. The developed Pitman Arm steering model using Lagrange theory is validated with actual steering system. Both mathematical model and real system are tested using MILS method to investigate the performance of the system. The results show that Pitman Arm steering is able to follow the desired inputs and proven that this steering system is capable to be implemented as an active steering system.

Simulation-based optimization of thermal systems

In this paper to improve manoeuvrability and jackknifing prevention, as well as increasing rollover stability of an articulated vehicle carrying liquid, a new control system coupled with an active roll control system and an active steering control system is presented. First, a 16-degrees-of-freedom nonlinear dynamic model of an articulated vehicle is developed. Next, the dynamic interaction of the liquid cargo with the vehicle is investigated by integrating a quasi-static liquid sloshing model with a tractor semi-trailer model. Initially, to improve the roll stability of the vehicle, an active roll control system is presented. The active anti-roll bar is employed as an actuator to generate the roll moment. Furthermore, the manoeuvrability increment and jackknifing prevention are targeted using the active steering control system. The main purpose of using the active steering controller is to track the desired values of tractor yaw rate, articulation angle and tractor lateral velocity in different roads, various filled volumes and different speeds. The active steering control system is designed based on a three-degrees-of-freedom dynamic model of the articulated vehicle carrying liquid and on the basis of sliding mode control. Simulation results confirmed robust performance of the control system for different filled volumes, especially during the critical manoeuvre. Further studies show that the tracking of the desired articulation angle has not only eliminated the off-tracking path, but also has made the semi-trailer rear end follow the fifth wheel path.

Regional rail transit, formed by the economic integration needs of urban agglomerations, is a comprehensive rail transit system with different kinds of transportation systems. Nowadays, although different kinds of rail transit systems are developing rapidly and the facilities are comprehensive, there is a lack of effective dynamic coordination among the various standards and subsystems. Consequently, the regional rail transit network cannot meet higher overall transport capacity and safety requirements. To solve this problem, this paper proposes a dynamic collaborative optimization method for regional rail transit based on passenger route guidance and train scheduling. This method takes the minimization of the maximum peak value of the road network dynamic risk as the optimization objective to establish a mathematical optimization model. The rail transit road network in the Chengdu–Chongqing area is taken as an example to establish a road network simulation model. Through the combination of the simulation model and intelligent optimization algorithms, the entire multi-standard rail transit network is dynamically optimized for train dispatching and passenger flow guidance. Finally, the effectiveness of the method is verified by the simulation of the actual rail transit network.

Multi-objective optimization of dew point indirect evaporative coolers for data centers

In this study, the functional safety attributes of vehicle steering system are examined and a real vehicle test method is proposed based on a whole vehicle in the loop (VIL) platform. By analyzing the general framework of the steering control system, extracting the limit test scenarios from road test conditions for transformation research and then applying it to the whole vehicle in the loop simulation test platform based on steerable axle coupling dynamometer, and conducting real vehicle level testing, the results of functional safety are analyzed in depth. Furthermore, the evaluation index system of extreme working conditions is established. The results of this study provide a comprehensive reference method for steering functional safety testing and evaluation that can be used by vehicle manufacturers and research institutions.

High-performance computing (HPC) systems consume huge amount of power, while bringing about higher operational costs, lower reliability. Power optimization has become an important target for HPC system design. Network energy optimization is significant for the energy optimization of the whole system. In this paper, the dynamic energy optimization method of network with MPI communication operation is presented, which can find MPI operation implementation with the least network energy by accurate dynamic energy estimation, and reduce the energy consumption of network. Taking barrier as an example, we validate the correctness and usefulness of the dynamic energy optimization method of network.

An enhanced scatter search method for the global dynamic optimization of nonlinear processes using the control vector parametrization (CVP) approach is presented. Sharing some features of the scatter search metaheuristic, this new method presents a simpler but more effective design which helps to overcome typical difficulties of nonlinear dynamic systems optimization such as noise, flat areas, nonsmoothness, and/or discontinuities. This new algorithm provides a good balance between robustness and efficiency in the global phase, and couples a local search procedure to accelerate the convergence to optimal solutions. Its application to four multimodal dynamic optimization problems, compared with other state-of-the-art global optimization algorithms, including an advanced scatter search design, proves its efficiency and robustness, showing a very good scalability.

The paper describes response surface methodology (RSM) based on design of experiments and analysis of variance (ANOVA) as a statistical design while developing a robust plasma transfer arc (PTA)coating process. Based on ANOVA, The relative important parameters with respect to surface at hardness values were identified in the Taguchi design, where they were further used in predictors. In addition, we applied three-dimensional graphs in RSM to develop a robust PTA response surface yielding the desired-better area of a treated layer. In this study, a quadratic polynomial with a Box-Behnken design is utilized. The results reveal that RSM provides the effective methods as compared to the traditional trial-and-error method for exploring the effects of controlled factors on response. A very good agreement was observed, as evidenced by R-squared value, 90%, between the predicted and the experimental data, and its error percent is found to be approximately 3.801% in the PTA-coating process. It is clear that RSM model demonstrated better accuracy in predicting surface hardness for PTA-coating process. Accordingly, RSM based on design of experiments was used as statistical PTA-coating design tools combined with the hardness model. Device zone optimization and yield enhancement have been demonstrated.

In this paper, the coordinated control of active steering and active roll control systems is investigated aiming to enhance vehicle lateral dynamics performance. A combined control structure is employed to design active steering controller, in which feedback controller is designed using robust mixed sensitivity control approach to minimise the tracking error of yaw rate and body sideslip angle. To further improve vehicle cornering capacity, an active roll controller based on the yaw rate feedback is designed by re-distributing roll moments between the front and rear axles to collaborate together with active steering. The proposed control system is evaluated via computer simulations under different manoeuvres. The simulation results show the overall performance improvement using the proposed coordinated control system in terms of the better handling performances.

Response Surface Methodology (RSM) is a statistical method to design experiments and optimize the effect of process variables. RSM is based on the principles of design of experiments or DOE. Design of experiments or DOE is a field of applied statistics that plans, conducts, analyses, and interprets controlled tests to assess factors that affect parameter values. Response surface methodology or RSM uses a statistical method for designing experiments and optimization. Despite the potential of response surface methodology to predict and optimize engine performance and emissions characteristics, a comprehensive review on RSM for biofuels, particularly for internal combustion engines (ICEs), is difficult to find. The review of response surface methodology is sometimes included together with other machine learning approaches such as ANN. Therefore, a review article that is exclusively written to address the specific of RSM for biofuel and ICE is required. This review article offers a fresh perspective on the application of RSM for biofuel in ICE. This article aims to critically review the RSM to optimize engine performance and emissions using biofuel. The study concludes with several possible research gaps for future works of RSM biofuel application. Although response surface methodology or RSM has drawbacks such as extrapolation inaccuracy outside the investigational ranges and discrete variables error, RSM has numerous advantages to design, model, estimate, and optimize biofuel for ICE with satisfactory accuracy. With its prediction and optimization capability, response surface methodology has the potential to assist the development of ICE optimization powered by biofuel for sustainability energy transition.

Nevirapine (NVP), used for the treatment of HIV/AIDS, exhibits unpredictable oral bioavailability, has a poor side effect profile and requires frequent dosing. Niosomes are novel drug delivery systems that have the potential to overcome these challenges. A thin layer hydration approach was used to produce niosomes and optimisation was undertaken using design of experiments (DoE) and response surface methodology (RSM) establish and identify parameters that may affect the manufacture of niosomes. The impact of cholesterol and surfactant content, hydration time and temperature on manufacture was investigated. Critical quality attributes (CQA) in respect of particle size (PS), entrapment efficiency (EE), polydispersity index (PDI) and the amount of NVP released at 48 hours was also assessed. The optimised niosome composition was identified and manufactured and the CQA characterised prior to placing the batch on stability for 12 weeks at 4±2 °C and 22±2 °C. The PS, PDI, EE and % NVP released at 48 h was 523.36±23.16 nm, 0.386±0.054, 96.8 % and 25.3 % for niosomes manufactured with Span® 20. Similarly, the parameters were 502.87±21.77 nm and 0.394±0.027, 98.0 % and 25.0 % for mean PS, PDI, EE and %NVP released at 48 h for Span® 80 niosomes. All characterisation was undertaken on the day of manufacture. In conclusion, a simple, cheap, rapid and precise method of manufacture of NVP niosomes was developed, validated and optimised using DoE and RSM and the product exhibited the target CQA.

This paper outlines a method for using an active steering system with two electrical actuators (one power-steering actuator and one superposition actuator) in order to manipulate the steering rack position without torque feedback to the steering wheel. To this effect, the power-steering actuator is used to implement a feed-forward control in order to compensate for the inertial effect introduced by the angle superposition. A rudimentary steering system model is used to derive the relevant transfer functions and assemble the control law for the superposition actuator. Experimental results of a research project at the BMW Group are included.