Optimum Design of the Control System for a Laser Beam Riding Guidance Anti-Tank Missile

The optimum theory and methods were adopted to design the laser beam riding guidance anti tank missile's control system in the short run. Through building the mathematical model of system, selecting a proper method and taking advantage of computer's high speed calculation and logic traits, an optimal controller was designed. Simulation results showed that the designed control system has fair performance and it satisfies the tactical and technical requirements. The results also demonstrate that by the combination of the optimizing methods and the computer the control system could be designed as soon as possible.

Free Riding Inhibition Mechanism Based on User Behavior in P2P File-Sharing System

In order to inhibit Free Riding in Peer-toPeer(P2P) file-sharing systems,the Free Riding Inhibition Mechanism Based on User Behavior(IMBUB) is proposed.IMBUB considers the regularity of user behavior and models user behavior by analyzing many definitions and formulas.In IMBUB,Bandwidth Allocated Ratio,Incentive Mechanism Based on User Online Time,Double Reward Mechanism,Incentive Mechanism of Sharing for Permission and Inhibition Mechanism of White-washing Behavior are put forward to inhibit Free Riding and encourage user sharing.A P2P file system BITShare is designed and realized under the conditions of a campus network environment.The test results show that BITShare's Query Hit Ratio has a significant increase from 22% to 99%,and the sharing process in BITShare is very optimistic.Most users opt to use online time to exchange service quality instead of white-washing behavior,and the real white-ishing ratio in BITShare is lower than 1%.We confirm that IMBUB can effectively inhibit Free Riding behavior in P2P file-sharing systems.

Advances in Active Suspension Systems for Road Vehicles

Active suspension systems(ASSs)have been proposed and developed for a few decades,and have now once again become a thriving topic in both academia and industry,due to the high demand for driving comfort and safety and the compatibility of ASSs with vehicle electrification and autonomy.Existing review papers on ASSs mainly cover dynamics modeling and robust control;however,the gap between academic research outcomes and industrial application requirements has not yet been bridged,hindering most ASS research knowledge from being transferred to vehicle companies.This paper comprehensively reviews advances in ASSs for road vehicles,with a focus on hardware structures and control strategies.In particular,state-of-the-art ASSs that have been recently adopted in production cars are discussed in detail,including the representative solutions of Mercedes active body control(ABC)and Audi predictive active suspension;novel concepts that could become alternative candidates are also introduced,including series active variable geometry suspension,and the active wheel-alignment system.ASSs with compact structure,small mass increment,low power consumption,high-frequency response,acceptable economic costs,and high reliability are more likely to be adopted by car manufacturers.In terms of control strategies,the development of future ASSs aims not only to stabilize the chassis attitude and attenuate the chassis vibration,but also to enable ASSs to cooperate with other modules(e.g.,steering and braking)and sensors(e.g.,cameras)within a car,and even with high-level decision-making(e.g.,reference driving speed)in the overall transportation system-strategies that will be compatible with the rapidly developing electric and autonomous vehicles.

Pressure Measurements from Five Different Nosebands at Rest, and During Riding at Walk, a Collected Gait, Backing up and a Full Stop

Background: Scientific procedures for addressing noseband fit and tightness, eliminating the risk of excessive and painful tightening, as well as quantitative measurements of pressures under the noseband while riding are either scarce or lacking. Purpose/Aim: To assess simple means of measuring pressure under different nosebands with a view to their adoption as scientific methodology. Method: Horses (n = 7) were fitted with five different bridles (A-E). Pressure distribution and intensity were measured using colour sensitive film (Fujifilm LLLW), assessing the level of pressure and distribution across the surface of the nosebands, as assessed and ranked by independent assessors. A CURO system was also used to measure pressure in real-time under nosebands whilst riding. Results: The colour-sensitive film for D & B were ranked 1st and 2nd, respectively. Regularity of pressure overall showed a statistical difference between nosebands (A & B significantly more unregular than the others). Pressure measurements revealed significantly different means (all P Conclusions: Pressures under nosebands can reach levels that appear capable of inflicting tissue damage, hence bridles and nosebands should be assessed using scientific methodology and not based on arbitrary and subjective criteria, as is currently the case.

Optimization of suspension system of off-road vehicle for vehicle performance improvement

Vehicle suspension design includes a number of compromises to provide good leveling of stability and ride comfort. Optimization of off-road vehicle suspension system is one of the most effective methods, which could considerably enhance the vehicle stability and controllability. In this work, a comprehensive optimization of an off-read vehicle suspension system model was carried out using software ADAMS. The geometric parameters of suspension system were optimized using genetic algorithm (GA) in a way that ride comfort, handling and stability of vehicle were improved. The results of optimized suspension system and variations of geometric parameters due to road roughness and different steering angles were presented in ADAMS and the results of optimized and conventional suspension systems during various driving maneuvers were compared. The simulation results indicate that the camber angle variations decrease by the optimized suspension system, resulting in improved handling and ride comfort characteristics.

Hierarchical Control of Ride Height System for Electronically Controlled Air Suspension Based on Variable Structure and Fuzzy Control Theory

The current research of air suspension mainly focuses on the characteristics and design of the air spring. In fact, electronically controlled air suspension （ECAS） has excellent performance in flexible height adjustment during different driving conditions. However, the nonlinearity of the ride height adjusting system and the uneven distribution of payload affect the control accuracy of ride height and the body attitude. Firstly, the three-point measurement system of three height sensors is used to establish the mathematical model of the ride height adjusting system. The decentralized control of ride height and the centralized control of body attitude are presented to design the ride height control system for ECAS. The exact feedback linearization method is adopted for the nonlinear mathematical model of the ride height system. Secondly, according to the hierarchical control theory, the variable structure control （VSC） technique is used to design a controller that is able to adjust the ride height for the quarter-vehicle anywhere, and each quarter-vehicle height control system is independent. Meanwhile, the three-point height signals obtained by three height sensors are tracked to calculate the body pitch and roll attitude over time, and then by calculating the deviation of pitch and roll and its rates, the height control correction is reassigned based on the fuzzy algorithm. Finally, to verify the effectiveness and performance of the proposed combined control strategy, a validating test of ride height control system with and without road disturbance is carried out. Testing results show that the height adjusting time of both lifting and lowering is over 5 s, and the pitch angle and the roll angle of body attitude are less than 0.15°. This research proposes a hierarchical control method that can guarantee the attitude stability, as well as satisfy the ride height tracking system.

Vehicle Ride Comfort Based on Matching Suspension System

The existing investigations of vehicle ride comfort mainly include motion characteristics analysis based on creating a multi-body dynamic simulation model,and the parameters analysis to improve the suspension control for the target.In the study of creating multi-body dynamics simulation models,there is usually without considering calibration and test verification,which make it difficult to ensure the production of engineering.In the study of improving the suspension control parameters for the target,there is a lack of systematic match about comfortable and human characteristics,so it is difficult to implement in the field of driving and leading the vehicle design.In this paper,based on the different characteristic of suspension system that effects on the vehicle ride comfort, according to the suspension system dynamic mechanism,the research methods of vehicle road test,bench test and CAE simulation is used,at the same time,several sensitivity analysis of vehicle ride comfort related to suspension stiffness and damping and speed is made. As a result,the key suspension systematic parameters are given that have important impact on vehicle ride comfort.Through matching parameters,a calibration analysis of suspension system based on human comfort is obtained.The analysis results show that the analysis methods for the design target of making the vehicle with best comfort are effective.On the basis of the theory study,five suspension parameter matching principles are explored to promise the vehicle with perfect ride comfort,which also provide theoretical basis and design methods for the passenger car best match of suspension system stiffness and damping.The research results have the promotional value of practicability and a wide range of engineering application.

Annoyance Rate Evaluation Method on Ride Comfort of Vehicle Suspension System

The existing researches of the evaluation method of ride comfort of vehicle mainly focus on the level of human feelings to vibration. The level of human feelings to vibration is influenced by many factors, however, the ride comfort according to the common principle of probability and statistics and simple binary logic is tmable to reflect these uncertainties. The random fuzzy evaluation model from people subjective response to vibration is adopted in the paper, these uncertainties are analyzed from the angle of psychological physics. Discussing the traditional evaluation of ride comfort during vehicle vibration, a fuzzily random evaluation model on the basis of annoyance rate is proposed for the human body＇s subjective response to vibration, with relevant fuzzy membership function and probability distribution given. A half-car four degrees of freedom suspension vibration model is described, subject to irregular excitations from the road surface, with the aid of software Matlab/Simulink. A new kind of evaluation method for ride comfort of vehicles is proposed in the paper, i.e., the annoyance rate evaluation method. The genetic algorithm and neural network control theory are used to control the system. Simulation results are obtained, such as the comparison of comfort reaction to vibration environments between before and after control, relationship of annoyance rate to vibration frequency and weighted acceleration, based on ISO 2631 / 1 （1982）, ISO 2631-1 （1997） and annoyance rate evaluation method, respectively. Simulated assessment results indicate that the proposed active suspension systems prove to be effective in the vibration isolation of the suspension system, and the subjective response of human being can be promoted from very uncomfortable to a little uncomfortable. Furthermore, the novel evaluation method based on annoyance rate can further estimate quantitatively the number of passengers who feel discomfort due to vibration. A new analysis method of vehicle comfort is presented.

Effects of therapeutic horseback riding on post-traumatic stress disorder in military veterans

Background:Large numbers of post-deployment U.S.veterans are diagnosed with post-traumatic stress disorder(PTSD)and/or traumatic brain injury(TBI),leading to an urgent need for effective interventions to reduce symptoms and increase veterans’coping.PTSD includes anxiety,flashbacks,and emotional numbing.The symptoms increase health care costs for stress-related illnesses and can make veterans’civilian life difficult.Methods:We used a randomized wait-list controlled design with repeated measures of U.S.military veterans to address our specific aim to test the efficacy of a 6-week therapeutic horseback riding(THR)program for decreasing PTSD symptoms and increasing coping self-efficacy,emotion regulation,social and emotional loneliness.Fiftyseven participants were recruited and 29 enrolled in the randomized trial.They were randomly assigned to either the horse riding group(n=15)or a wait-list control group(n=14).The wait-list control group experienced a 6-week waiting period,while the horse riding group began THR.The wait-list control group began riding after 6 weeks of participating in the control group.Demographic and health history information was obtained from all the participants.PTSD symptoms were measured using the standardized PTSD Checklist-Military Version(PCL-M).The PCL-M as well as other instruments including,The Coping Self Efficacy Scale(CSES),The Difficulties in Emotion Regulation Scale(DERS)and The Social and Emotional Loneliness Scale for Adults-short version(SELSA)were used to access different aspects of individual well-being and the PTSD symptoms.Results:Participants had a statistically significant decrease in PTSD scores after 3 weeks of THR(P≤0.01)as well as a statistically and clinically significant decrease after 6 weeks of THR(P≤0.01).Logistic regression showed that participants had a 66.7%likelihood of having lower PTSD scores at 3 weeks and 87.5%likelihood at 6 weeks.Under the generalized linear model(GLM),our ANOVA findings for the coping self-efficacy,emotion regulation,and social and emotional loneliness did not reach statistical significance.The results for coping self-efficacy and emotion regulation trended in the predicted direction.Results for emotional loneliness were opposite the predicted direction.Logistic regression provided validation that outcome effects were caused by riding longer.Conclusion:The findings suggest that THR may be a clinically effective intervention for alleviating PTSD symptoms in military veterans.

P2P中抑制Free riding行为的激励机制-节点所得税法

由于P2P网络节点的匿名性和贡献资源的自愿性,绝大多数节点缺乏提供服务的积极性,从而引发了P2P网络中的"Free riding"问题。在分析"Free riding"问题的基础上,依据拉弗曲线和美国个税方案,提出了一种基于个人所得税的激励机制(PIIM)。基于"富人多交税,穷人少交税"的思想来实现收入的二次分配,进而实现P2P系统的节点公平性。基于校园网运用的实验表明,该激励机制促进了社会公平,达到了激励节点参与资源共享的目的。

Experimental investigation on vibration characteristics of the medium-low-speed maglev vehicle-turnout coupled system

The steel turnout is one of the key components in the medium–low-speed maglev line system.However,the vehicle under active control is prone to vehicle–turnout coupled vibration,and thus,it is necessary to identify the vibration characteristics of this coupled system through field tests.To this end,dynamic performance tests were conducted on a vehicle–turnout coupled system in a medium–low-speed maglev test line.Firstly,the dynamic response data of the coupled system under various operating conditions were obtained.Then,the natural vibration characteristics of the turnout were analysed using the free attenuation method and the finite element method,indicating a good agreement between the simulation results and the measured results;the acceleration response characteristics of the coupled system were analysed in detail,and the ride quality of the vehicle was assessed by Sperling index.Finally,the frequency distribution characteristics of the coupled system were discussed.All these test results could provide references for model validation and optimized design of medium–low-speed maglev transport systems.

Cubic-BN-Like Structure of B-C-N Films Synthesized by Plasma Source Ion Nitriding

Plasma source ion nitriding has emerged as a low-temperature,low-pressure nitriding approach for implanting nitrogen ions and then diffusing them into bulk materials.The ion-plating B-C films were nitrided to synthesize B-C-N films at a nitriding temperature from 300 to 500℃.The x-ray photoelectron spectroscopy and diffuse reflectance Fourier transform infrared spectra analyses showed that the amorphous B-C-N films synthesized at 500℃ are composed mainly of cubic-BN-like and hexagonal-BN-like plain microdomains.The higher nitriding temperature contributes to the formation of cubic-BN-like B-C-N structure in the B-C-N films.

Sensitivity analysis method for increasing the passenger demands of parking and riding

Focused on finding out the relationship between passenger demands of P&R and its influencing factors, a nested-logit mode choice model was developed based on the characteristic of different modes and transfer rules. The utility functions were given respectively according to the characteristic of each alternative. Passenger demands of different modes between O-D pairs were obtained by making use of the binary logit model. Then an equilibrium model for different modes was proposed. Under this condition, the approximate relationship between passenger demands of different modes and their characteristic indexes was modeled by the sensitivity analysis method. Shift volume among different modes was achieved by utilizing this model when their characteristic indexes were changed. A case study indicates that the model and algorithm presented in this paper are effective.

The Effects of Therapeutic Horseback Riding Program on Motor Skills inChildren with Autism Spectrum Disorder

Therapeutic horseback riding(THR)as an animal-assisted intervention is one of the innovative approaches emer-ging in the treatment for children with autism spectrum disorder(ASD).The current study was designed to inves-tigate the effects of a 12-week,twice a week THR program on motor skills in sixty-eight children with ASD aged 5–10 years old.All participants selected met the DSM-V criteria for ASD,and a total offifty-three participants completed the study.A randomized controlled trial design was utilized for the study.Data was collected via a pre-THR test,interim-THR test,and post-THR test to investigate the possible changes in motor skills throughout the 12-week THR program.Results showed that the THR program significantly improved overall motor skills across time points(p<0.05)and sub-skills of run,gallop and two-hand catch(as compared to the control group,p<0.05).In conclusion,the THR program may be an effective option for improving motor skills in children with ASD and further investigation with a longer period of intervention is warranted.

Design, Development and Testing of an Air Damper to Control the Resonant Response of a SDOF Quarter-Car Suspension System

An air damper possesses the advantages that there are no long term changes in the damping properties, there is no dependence on working temperature and additionally, it has less manufacturing and maintenance costs. As such, an air damper has been designed and developed based on the Maxwell type model concept in the approach of Nishihara and Asami [1]. The cylinder-piston and air-tank type damper characteristics such as air damping ratio and air spring rate have been studied by changing the length and diameter of the capillary pipe between the air cylinder and the air tank, operating air pressure and the air tank volume. A SDOF quarter-car vehicle suspension system using the developed air enclosed cylinder-piston and air-tank type damper has been analyzed for its motion transmissibility characteristics. Optimal values of the air damping ratio at various values of air spring rate have been determined for minimum motion transmissibility of the sprung mass. An experimental setup has been developed for SDOF quarter-car suspension system model using the developed air enclosed cylinder-piston and air-tank type damper to determine the motion transmissibility characteristics of the sprung mass. An attendant air pressure control system has been designed to vary air damping in the developed air damper. The results of the theoretical analysis have been compared with the experimental analysis.

Low Voltage Ride through Control Capability of a Large Grid Connected PV System Combining DC Chopper and Current Limiting Techniques

This paper presents the development and performance capability of a comprehensive Low voltage ride through (LVRT) control scheme that makes use of both the DC chopper and the current limiting based on the required reactive power during fault time. The study is conducted on an 8.5 MW single stage PV power plant (PVPP) connected to the Rwandan grid. In the event of fault disturbance, this control scheme helps to overcome the problems of excessive DC-link voltage by fast activation of the DC chopper operation. At the same instance, AC current is limited to the maximum rating of the inverter as a function of the injected reactive current. This helps overcome AC-over- current that may possibly lead to damage or disconnection of the inverter. The control scheme also ensures voltage support and power balance through the injection of reactive current as per grid code requirements. Selected simulations using MATLAB are carried out in the events of different kinds of fault caused voltage dips. Results demonstrate the effectiveness of the proposed LVRT control scheme.

H_∞ CONTROL OF AN ACTIVE SUSPENSION SYSTEM

An H ∞ controller for an active suspension system is designed, which has taken the performance of ride comfort and the system robustness into account. Simulation results show that a concentrated weighting of the car body acceleration output, for the frequency where human being are most sensitive to vibration, has been executed by introducing the frequency dependent weighing function, thus the suspension acceleration frequency response characteristic can be improved. It is also pointed out that the designed controller is effective in the system robustness against the fluctuation of parameter of system.

Determining the characteristics of the initial fixed-focus of laser beam riding guidance information field

Determining characteristics of the initial fixed-focus are a key technique for the design of laser beam riding guidance missile. Through analyzing the effects of the initial cone information field in guidance and control system of missile, those effects are considered as an approximate lead com- pensation network. The position and time of guidance spot initial fixed-focus can be designed. This method is applied to determine the characteristics of the initial fixed-focus of laser information field for a laser beam guidance gun-launched missile. The results of design and simulation show that the initial cone information field apparently speeds up convergence on the initial trajectory, and provides a guarantee for the implementation of minimum range index of a missile system.

A PEER-TO-PEER INCENTIVE SCHEME FOR OVERCOMING FREE RIDING

Free riding has a great influence on the expandability,robustness and availability of Peer-to-Peer(P2P) network.Controlling free riding has become a hot research issue both in academic and industrial communities.An incentive scheme is proposed to overcoming free riding in P2P network in this paper.According to the behavior and function of nodes,the P2P network is abstracted to be a Distributed and Monitoring-based Hierarchical Structure Mechanism(DMHSM) model.A utility function based on several influencing factors is defined to determine the contribution of peers to the whole system.This paper also introduces reputation and permit mechanism into the scheme to guarantee the Quality of Service(QoS) and to reward or punish peers in the network.Finally,the simulation results verify the effectiveness and feasibility of this model.

Design and evaluation of cab seat suspension system based on negative stiffness structure

To improve the vibration-isolation performance of cab seats,the optimization model of the seat suspension system of construction machinery cabs is proposed based on the negative stiffness structure.The negative stiffness nonlinear kinetic equation is established by designing the seat negative stiffness suspension structure(NSS).Using MATLAB,the different parameters of the suspension system and their influences on the dynamic stiffness are analyzed.The ideal configuration parameter range of the suspension system is obtained.Meanwhile,the optimization model of NSS is proposed,and the vibration transmissibility characteristics are simulated and analyzed by different methods.The results show that the displacement and acceleration amplitudes of the optimized seat suspension system are evidently reduced,and the four-time power vibration dose value and root mean square calculation values in the vertical vibration direction of the seat decrease by 86%and 87%,respectively.Seat effective amplitude transmissibility(SEAT)and the vibration transmissibility ratio values also decrease.Moreover,the peak frequencies of the vibration transmitted to the driver deviate from the key frequency values,which easily cause human discomfort.Thus,the design of the seat suspension system has no effect on the health condition of the driver after being vibrated.The findings also illustrate that the NSS suspension system has good vibration-isolation performance,and the driver's ride comfort is improved.