Dynamic characteristic analysis and optimization of high power-density steering gear

Steering gear is an important device on a ship,whose performance quality affects ship greatly.Aiming at high power-density steering gear which is composed of electro-hydraulic system and ball rotary-oscillating actuator,a mathematics model of the steering gear system is deduced.The system optimization design is carried out using optimization theory.Dynamic simulations of the pre and post optimized systems are made by MATLAB software to analyze dynamic characteristics.The analysis results show that the optimized steering gear can meet practical needs.     

Analysis of model-following control for multi-axle steering vehicle

The dynamic model of multi-axle steering vehicle is improved by considering the impact of the front-axle mechanical steering on the vehicle steering performance and implying the front-axle wheel angle in control variables to reduce the difficulty of vehicle control. On the basis of modified dynamic model, the multi-axle vehicle is analyzed by combining model-following method with pole assignment process. The transient response and frequency domain characteristics of the yaw angle velocity and sideslip angle at different speeds are obtained. The results indicate that, using model-following method to control vehicle can obtain desired tracking effects. At high speed, the transient response has no overshoot, the response time is shortened, and the stability of vehicle is improved.     

Handling performace evaluation of a vehicle stability control system based on a driver model

By combining a driver model, a vehicle system dynamics model, and a vehicle lateral stability control system, the performance of the driver vehicle road closed loop system through a pylon course slalom test was simulated. The simulation was done in accordance with the GB/T6323.1-94 standard. Vehicle stability control system effectiveness was evaluated by measuring the mean maximum yaw rate and the mean maximum steering wheel angle. The simulation results showed the slalom test value with lateral stability control was approximately 4% higher than without a stability control system. This indicates the controlling system improves vehicle handling stability.     

Vehicle Lateral Stability Control Based on Sliding Model Control

In view of the vehicle cornering or path changing under ultimate handling maneuver, a 3-DOF nonlinear vehicle dynamics model which takes the vehicle lateral velocity, yaw rate and body roll angle as the State variables is presented. Based on the dynamic analysis, the method which using additional yaw moment produced by different longitudinal braking force among each wheels to improving vehicle handling stability in emergency situations is discussed. Considering the sideslip angle as one of the vehicle state variables is difficult to measuring, the sideslip angle estimation based on vehicle dynamic model and kinematics is designed. And then, based on the theory of siding model control, the combining sliding model control system is founded, which taking the vehicle yaw rate and body side-slip angle errors between the estimated and the real as the input variables, and taking the braking torque and the steering angle as control aims. The simulation results indicate that the control method can effectively improve the vehicle lateral handling stability.     

Single-point preview control for unmanned high-speed4WID-4WIS vehicle path tracking

As for the actuation redundancy, strong nonlinearity and uncertainty, a kind of single-point preview control approach for the unmanned high-speed four-wheel-independent-drive & steering (4WID-4WIS) vehicle path tracking is proposed based on the control allocation and the Active Disturbance Rejection Control(ADRC) methods. The vehicle single-point preview system dynamic model for path tracking is built. The control system architecture with the control allocation unit as the core is constructed. The decouple single-point preview ADRC controller for path tracking is designed. Then the quasi-inertial parts used to generate control objectives are proposed and its rationality is discussed. The control allocation solution method for the 4WID-4WIS vehicle path tracking is subsequently presented. The simulations are conducted to illustrate the validity of the single-point preview control method proposed. The results show that the unmanned high-speed 4WID-4WIS vehicle can track the circular arc double-lane change path rapidly and accurately.     

Application of state feedback and observer inmulti-axle vehicle steering system

A 3-degrees of freedom multi-axle vehicle dynamic model is established.Taking account of the practical difficulties for measuring the sideslip,rolling angles and rolling angle speed,a Luenberger observer is designed,and the simulation and analysis of the Luenberger observer are performed.The results show that the Luenberger observer has excellent characteristics in the considered speed range in tracking path.Then,a state feedback controller is designed on the basis of the Luenberger observer,and simulation of a multi-axle vehicle is also carried out.The results show that the performances of a multi-axle vehicle with the proposed control strategy is better than a multi-axle vehicle with front wheel steering strategy,and its control system has fine dynamic characteristic and strong robustness,so multi-axle vehicle with the proposed control strategy can improve vehicle handling stability and security.     

Automatic Transmissions Technique and Development Trend for Heavy Vehicle

Gear change automatic is the main development trend for power train of heavy vehicle. In this paper, transmission theory and characteristic of several type heavy vehicle, include the automatic transmission system development trend of overseas heavy vehicle, especially for the application of electrical control automatic manual transmission system in heavy vehicle were introduced, the analysis of develop the automatic transmission system for domestic heavy vehicle was put forward, the key technique which must be solved for the exploitation of electrical control automatic manual transmission system in heavy vehicle were discussed.     

Modeling and simulating the vehicle riding dynamics considering gradient effects

Considering road characteristic parameters such as lateral gradient, longitudinal gradient and synthetic gradient, and based on 15 degrees of freedom (DOF) vehicle dynamics model, the authors develop the vehicle dynamics model, tire vertical load variation model and whole vehicle riding dynamics simulation model combined with steering system, braking system, power train system, wheel and suspension models. The situations are compared under different lateral, longitudinal, synthetic gradient and vehicle speed. The simulation results show that yaw rate maintains invariably to longitudinal gradient variation, but decreases gradually with the increase of lateral and synthetic gradient. The margin of fluctuation and peak value increase with the increase of vehicle speed under the same gradient; front wheel sideslip angle maintains invariably to longitudinal and synthetic gradient variation, yet increases with the increase of lateral gradient; the roll rate decreases and then increases with the increase of lateral and synthetic gradient, and the margin of fluctuation and peak value increase with the vehicle speed increase under the same longitudinal gradient.     

Power Train of a New Type of Hybrid Electric Vehicle

The powertrain of a new type of zero emission electric vehicle is researched, which powered primarily by air-breathing proton exchange membrane (PEM )fuel cells with gaseous hydrogen as fuel,and with Lead-acid battery as assistant power.The fuel cell system provides power for the vehicle while the vehicle travel at a cruising speed,and the exceed power will charge for battery.The fuel cell and the battery system will together provide power to the vehicle during periods of peak power demand such as vehicle acceleration or traveling at a high constant speed.At the same time, the powertrain parameter of this fuel cell vehicle are matched reasonably.At last, the dynamic of an electric vehicle is simulated, and the result shows that the dynamic performance perfectly meets the need of the design target.     

Application Research on Vehicle Handling Stability Using Simulative Analysis

A multi-body simulation approximate model of a vehicle using ADAMS software is established, and a frontrear suspension system, a steering system, the tires and all connectors are studied. Vehicle handling stability under different tests is simulated. The result is credible and valid, the parameter of vehicle model is amended expediently. This simulation can help design products and reduce a development cycle.     

Dynamic simulation of and experimentation with tracked vehicle hydrostatic steering characteristics of zero differential systems of a power shift steering transmission

This research investigated problems influencing tracked vehicles steering dynamic characteristics, such as rolling resistance during straight driving, steering centrifugal resistance, acceleration resistance during straight driving, scratching soil resistance of steering. Based on research about the relationship between the hydraulic steering regulation speed system and its maximum stable work pressure when vehicles have central steering on good roads (such as cement and rural roads), a zero differential hydraulic steering system of power shift steering transmission can ensure that vehicles maintain straight ahead stability through reasonably matching a steering drive system. The test indicates that vehicles have good dynamic characteristics when the work pressure accounted for 60% to 80% of the security work pressure.     

Analysis on starting characteristic of continuously variable transmission system with reflux power

Considering on the characteristics of the transmission system and some key units of continuously variable transmission system with reflux power, a dynamic simulation model and a control strategy are established. The design method of the new continuously variable transmission system is verified by simulation. The simulation result on this continuously variable transmission system shows that the rotating speed of the driven plate can rise up rapidly during starting clutch engagement, and the sliding friction power is lower than 3 kJ which is nearly equal to one third of the friction power of the traditional vehicle.     

Analysis and synthesis of time-dependent reliability for integrated steering mechanisms

The steering performance of vehicle is directly affected by the kinematic accuracy of steering trapezoid mechanisms. Considering uncertainties that exist in steering mechanisms, the theory of kinematic time-dependent reliability is adopted to study the analysis and synthesis of the integrated mechanisms. A new method for high accuracy actual steering mechanisms design with the uncertainties is presented. Probabilistic model of kinematic error with dimension random variable is established, and analytical models of up-crossing rate and down-crossing rate for solving the time-dependent reliability of steering mechanisms are derived. A determination model and reliability model for mechanisms synthesis are built, and a numerical example are given to verify the effectively and robustness of time-dependent reliability synthesis method.     

Management Information System of Power Based on C/S and B/S Mode Combined

After analyzing the feature of C/S and B/S modes, a kind of MIS for power industry, which combined C/S with B/S, is put forward. The C/ S platform is developed with the Powerbuilder 7.0 and SQL Server 7.0, and the B/ S platform is developed with ASP and IIS5.0+ SQL Server7.0. Electric power management information system should be constituted by the seventh statures mold piece, which are the electricity measures to collecting, electricity charges settling accounting system, the safety system et al. In order to meet the demand of data safety of enterprises, the method of passing data between C/S and B/S is introduced.     

Research and development of the real time remote monitoring control system of hybrid electric vehicles

This paper develops a vehicle carried remote data acquisition terminal based on GPS/GPRS integrated DTU(data transfer unit) and CAN Bus data acquisition module, and built a parameter remote monitoring system of HEV with GPRS and Internet. By using PIC18F4580 with built in CAN control module and industrial DTU MD610G, we transmitted the parameter data and GPS information of the HEV(Hybrid Electric Vehicle) terminals to the remote data control center through GPRS(General Packet Radio Service) and INTERNET. Taking VC++ as the development tool, we programmed a monitoring software of data exchanging, data processing and monitoring. The software also has the function of CANoe data playbacking and strengthened the system versatility. Eventually, the parameter remote monitoring system of HEV is developed. The experiment results show that the system works well.     

Simulation for the Power System of Fuel Cell/battery Electric Vehicle

The developmemt and research of taking fuel cell /battery as electric vehicle power is a new direction in abroad. A real-time simulation model for power driving system of a fuel cellbattery powered electric virtual vehicle is established. This electric vehicle powered primarily by 30 kw proton exchange membrane (PEM)fuel cells, with Lead-acid battery as assistant power, and with focus classis as virtual vehicle classis.The electric vehicle is simulated on the advisor platform, and the NEDC driving pattern simulation results show that the electric vehicle can satisfy the need of performance.     

Analysis of Unified Power Flow Controller in Damping Low Frequency Oscillation of Power System

With the development and complication of power system, the problem of low frequency oscillation in electric network becomes obvious. Unified Power Flow Controller is one of the most powerful facilities in Flexible AC Transmission Systems, which can improve the transient stability and damp the low oscillation in power system with suitable control. Considering the characteristics of inverter's output voltage magnitude, adjustment of phase and process of charge and discharge of dc capacitance, the dynamic model of UPFC is proposed by a series of nonlinear differential coefficient equations. Based on UPFC's dynamic model, the linear optimal controller of UPFC with state feedback is proposed. In this way, the low frequency oscillation is damped effectively. A simulation is processed basing the theory.     

Vehicle stability control system design using optimal allocation of yaw moment

In order to improve vehicle handling stability,a control system using optimal allocation of yaw moment was designed.The first layer is a linear quadratic regulator (LQR) controller,which optimizes a desired yaw moment to work on the vehicle and calculates reference wheel slip for the target wheel.The second layer of the control system is a PID controller which can track the reference wheel slip rate,and then apply braking torque on the target wheel to make the vehicle stable.Simulations are carried out by using an 8-dof nonlinear vehicle model under different conditions.The simulation results indicate that the designed control system can effectively improve vehicle handling stability.     

Intel I igent Distributed Control System- Combination of Artificial Intelligence and Distributed Control System

This paper gives a simple introduction about artificial intelligence (AI) and distributed control system (DCS). It suggests an idea of intelligent distributed control system (IDCS), moreover, in this paper, the hardware composition and the software composition of IDCS were provided.     

Externally Pressurized Gas Journal Bearings in Power MEMS of Quasi Gas Power Cycle

An original thermodynamic idea for Power MEMS, which is called as quasi gas power cycle, is proposed to further intensify energy density and simplify structure of Power MEMS. Because gas supply with preset high pressure is set up in the Power MEMS engine of quasi gas power cycle, it is convenient for the Power MEMS engine to employ externally pressurized gas bearings to improve the performance of its bearings. Therefore mal design philosophy and structural type of the hyrostatic journal bearing as well as the hyrostatic thrust bearing in the Power MEMS engine are investigated, considering the limiting factor on meso scale. Then the structural and operational parameters are analyzed, and the optimal designs of typical externally pressurized gas bearings are put forward. Moreover the feasibility of the externally pressurized gas bearings applied to the Power MEMS engine is further verified by the calculation of load-carrying capacity of the hyrostatic gas bearings.