Steering Valve Research Articles

Horizontal Trash Rack Diverter Trash (HTDT) to Minimize Trash Clogging at the Intake of Micro-Hydro Power Plant

Clogging of Trash at the Micro Hydro-Power Plant can reduce the discharge, head, and micro-hydro production. Trash racks are currently less efficient in solving Trash clogging, so it needs appropriate technology innovation with the Horizontal Trash rack Diverter Trash (HTDT) which functions to get rid of or divert Trash. Diversion of Trash as well as increasing and stabilizing the discharge is important so that the innovation of adding a flow steering valve is needed (HTDT+V). The results of the research at β20° is the most optimal angle, the highest speed at the intake channel Cm4 V 0.7 m/s and HTDT + V β20° V 0.8 m/s occurs an increase in speed. Trash paste time β20° t 2.76 seconds, faster than the angle β0°, β5°, β30° Trash paste time t3.5 seconds. The HTDT+V installation increases the inflow velocity (V) in the intake channel by 60% and increases the discharge (Q) by 50%.

Design optimization of an articulated frame steering system

The articulated frame-steered vehicles (AFSV) exhibit enhanced maneuverability but reduced yaw stability and greater steering power consumption. Apart from kinematics of the steering system, the dynamics of the actuating system strongly influence the performance of the AFSV, which is generally neglected in the reported studies. In this study, a yaw-plane model of the articulated vehicle coupled with the kinematic and dynamics properties of the steering struts is formulated to identify objective measures of the AFSV under steering inputs. The results suggest that the vehicle yaw oscillation/stability, steering power efficiency and maneuverability can be objectively measured in terms of the strut length, yaw oscillation frequency and damping ratio, steering gain, and steering response rate and overshoot. The layout of steering struts and properties of the steering valve and hydraulic fluid are optimized while employing the weighted-sum method and a combination of pattern search and sequential quadratic programming algorithms. The relative weights of individual performance measures were obtained using the analytic hierarchy process (AHP) model. The solutions of the optimization problem revealed more compact articulated frame steering (AFS) system design with over 20% reduction in strut length and 24% gain in the yaw oscillation frequency. Increasing the fluid bulk modulus resulted in more compact AFS layout and further increase in the yaw oscillation frequency with lower response overshoot. The optimal design based on weighted sum of various performance measures, however, revealed negligible changes in terms of the steering power efficiency.

Effect of articulated frame steering on the transient yaw responses of the vehicle

The directional performance characteristics of articulated frame steering vehicles are known to be strongly coupled with the kinematic characteristics and the dynamic characteristics of the steering system. The reported studies on articulated frame steering generally focus on the yaw divergence behaviour or the snaking tendency of the vehicle based on its free-yaw-oscillation response, while neglecting important contributions due to the kinematics and the dynamics of the steering system. This study characterizes both the free-yaw-oscillation response and the transient steering response of an articulated frame steering mining vehicle, considering the kinematics of the steering struts together with the dynamics of the flow volume-regulated steering valve and the actuating system. The validity of the analytical vehicle and steering system model is demonstrated using the measured data acquired for the vehicle. The free-oscillation behaviour of the articulated frame steering is characterized in terms of the yaw-mode natural frequency and the yaw damping ratio. The transient responses of the articulated frame steering are assessed in terms of the steering gain, the rate of articulation and the articulation overshoot. The effects of the variations in the various articulated frame steering parameters on the free response and the transient response are subsequently investigated and discussed so as to seek guidance for the design of the articulated frame steering system. It is shown that a higher bulk modulus of the hydraulic fluid and longer steering-arm lengths yield a higher yaw stiffness of the articulated frame steering system and thereby a higher frequency of the yaw oscillations. Higher leakage flows and higher viscous seal friction cause a higher yaw damping coefficient but decrease the steering gain and the articulation rate of the vehicle.

Real-time simulation of dynamic vehicle models using a high-performance reconfigurable platform

With the increase in the complexity of models and lack of flexibility offered by the analog computers, coupled with the advancements in digital hardware, the simulation industry has subsequently moved to digital computers and increased usage of programming languages such as C, C++, and MATLAB. However, the reduced time-step required to simulate complex and fast systems imposes a tighter constraint on the time within which the computations have to be performed. The sequential execution of these computations fails to cope with the real-time constraints which further restrict the usefulness of Real-Time Simulation (RTS) in a Virtual Reality (VR) environment. In this paper, we present a methodology for the design and implementation of RTS algorithms, based on the use of Field-Programmable Gate Array (FPGA) technology. We apply our methodology to an 8th order steering valve subsystem of a vehicle with relatively low response time requirements and use the FPGA technology to improve the response time of this model. Our methodology utilizes traditional hardware/software co-design approaches to generate a heterogeneous architecture for an FPGA-based simulator by porting the computationally complex regions to hardware. The hardware design was optimized such that it efficiently utilizes the parallel nature of FPGAs and pipelines the independent operations. Further enhancement was made by building a hardware component library of custom accelerators for common non-linear functions. The library also stores the information about resource utilization, cycle count, and the relative error with different bit-width combinations for these components, which is further used to evaluate different partitioning approaches. In this paper, we illustrate the partitioning of a hardware-based simulator design across dual FPGAs, initiate RTS using a system input from a Hardware-in-the-Loop (HIL) framework, and use these simulation results from our FPGA-based platform to perform response analysis. The total simulation time, which includes the time required to receive the system input over a socket (without HIL), software initialization, hardware computation, and transfer of simulation results back over a socket, shows a speedup of 2 × as compared to a similar setup with no hardware acceleration. The correctness of the simulation output from the hardware has also been validated with the simulated results from the software-only design.

Electrorheological Self-Amplifiying Microvalve

This paper presents the design structure of an electrorheological self-amplifying microvalve for electrorheological fluids. This self-amplifying valve can thereby be devided into two main parts, the steering valve and the self-amplifying unit. The first step - combining a conventional electrorheological valve with a self-amplifying unit is one very important aspect and already induced to a promising result in the past. In a next step the conventional electrorheological valve is replaced by an electrorheological microvalve. Smaller dimensions are the final result. The simulation results of the whole system based on measurement results of the electrorheological microvalve are presented in this paper.

Control of an air pressure actuated disposable bioreactor for cultivating heart valves

A disposable injection molded bioreactor for growing tissue-engineered heart valves is controlled to mimic the physiological heart cycle. Tissue-engineered heart valves, cultured from human stem cells, are a possible alternative for replacing failing aortic heart valves, where nowadays biological and mechanical heart valves are used. Growing and conditioning is done by mechanically stimulating the tissue in a bioreactor. The disposable injection molded bioreactor uses flexible membranes and steering valves to mimic a physiological heart cycle. In this work, an air pressure actuation control system for this bioreactor is designed. One membrane is position controlled to achieve a desired flow through the heart valve, while another membrane controls the aortic pressure. A third actuator controls a steering valve used to impose a resistance on the flow back to the first membrane, in order to control the heart valve closing pressure. Due to the repetitive character of the setpoints, repetitive controllers are designed and implemented. A high position tracking performance is achieved and pressure setpoints are mimicked successfully, while preventing large pressure oscillations and suppressing disturbances that could be damaging for the tissue heart valve. The control system allows full adjustability of operating conditions needed for the growing, conditioning and testing phases of tissue engineered heart valves.

Web-Based Collaborative Design of Auto Steering Hydraulic Rotating Valve

The design quality of auto steering hydraulic rotating valve directly affects driving security, operating stability and ride comfort. Active server page (ASP) technology is applied in the study of working principal of auto steering hydraulic valve, calculation method of web-based design and parameterization design for parts. An collaborative design platform in network environment is built. The collaborative design of auto hydraulic Steering valve based on network is realized through some key technologies of safety technology in network design, database technology, graphical viewing technology, and COM technology.

Simulation Environment for Testing Guidance Algorithms with Realistic GPS Noise Model

This paper presents a simulation framework and realization for a tractor-trailer system with an active joint in an agricultural field setting. In addition, all real system measurements are also provided for hardware-in-loop testing. In the simulator, the kinematics and dynamics of the tractor and the trailer are modelled, as well as noises related to each measurement. The noise statistics and typical amount of wheel slip were identified from field tests. For hardware-in-loop testing the simulator provides the measurements in CAN-bus (ISO 11783 standard) and the commands to the steering valve are also received via the bus. CAN-bus is the only link between the guidance system under test and the simulation environment. In addition, the simulation environment contains a graphical front end, where the trajectories of the vehicle can be observed and analyzed.The most challenging noise related to the simulation of an environment is related to the GPS and its inaccuracies, as the noise properties are far from Gaussian white noise. In this paper an error model for GPS noise is presented as a position measurement and noise range statistics to the measurement. The simulation environment is tested with nonlinear model predictive control algorithms.

CAE Analysis and Manufacture to Valve Test Part of Power Steering Valve Balance Tester

CAE Analysis and Manufacture to Valve Test Part of Power Steering Valve Balance Tester

Simulation of cavitation in rotary valve of hydraulic power steering gear

Hydraulic power steering gear supplies assistant power by liquid stream. The stream will be changed greatly for the flow field formed by the rotary valve will vary during steering. And the change of the stream in this narrow field will (be big enough to) cause the fluctuation of the assistance power and noise of the steering gear. 3-D meshes of the flow field between the sleeve and the rotor of the valve with different structure parameters such as entry caliber and groove depth were set up and a general CFD code-Fluent was used to analyze the stream performance. The results including pressure and gas-phase’s volume fraction were analyzed under certain operation flow rate. It was found that the entry caliber did not affect the operation pressure of the valve under the same flow rate but affected the gas-phase’s volume fraction of the flow field, and so did the groove depth of the valve’ sleeve and rotor. Many researches have pointed that the noise of steering valve is almost cavitation noise, that is, the gas-phase in the flow field has great correlation with rotary valve noise. Based on these analyses of the stream in the rotary steering valve, this paper gave suggestion that increasing entry caliber of the rotary valve and choosing appropriate groove depth will reduce the valve noise.

유량 및 부하가 변하는 상태에서의 양로드 유압실린더의 위치제어시스템

A double-end rod hydraulic cylinder is widely used with a steering valve for the steering control system in large tractors. For the development of automatic steering controller, the feasibility of using a proportional control valve replacing the conventional manual steering valve to control the position of hydraulic steering cylinder was investigated in terms of the max. overshoot, the steady-state error and the rise time. A simulation model for the electrohydraulic steering system with load using AMESim package was developed to be valid so that the proper control algorithm could be chosen through the computer simulation. It could be concluded that the P-control algorithm was sufficient to control the electrohydraulic steering system, where the control frequency should be no greater than 20 Hz at the P-gain of 5. In particular, the performance of the developed steering controller was satisfactory even at the conditions of varying flow rates and loads.

Fault tolerant real time control system for steer-by-wire electro-hydraulic systems

A steer-by-wire (SBW) control system is presented with emphasis on safety issues. The applications are in articulated vehicles such as the wheel type loaders, articulated trucks, and others. The electro-hydraulic (EH) power circuit is controlled by two embedded electronic control modules (ECM), the primary ECM and backup ECM. The two ECMs monitor each others condition. If one detects fault in the other, it takes over the control functions. There are two main control algorithms that run in the ECMs in real-time: the steering valve control algorithm and the failure detection algorithm. The valve control algorithm basically generates command signal to the steering valve based on operator steering column signal as well as other machine condition sensors. The failure detection algorithm implements a fault detection logic for both input sensors and output drivers, and flags the corresponding warning for to the operator, and take a predefined action depending on the type of the failure detected. A unique fault strategy organization is implemented by inspecting the failure behavior on both the component and the system levels. The failure detection algorithm also determines the most likely “good” sensor signal from a set of redundant sensors for each critical measurement. Based on these good sensors data, the steering control algorithm sends two output signals: the control signal to the steering EH circuit valve and the control signal to the steering wheel force feedback device (i.e. a brake or a motor) to give operator feedback about the steering conditions. Finite state machine (FSM) concept is used to design the fault handling algorithms for both the component level and the system level failure. The probability of the system being at normal steering state or at any other steering failure state is determined. Failure mode probabilities of steering system components are also determined.

Automatic tractor guidance using carrier-phase differential GPS

Previous research at Stanford University involving automatic aircraft landings using a high-precision form of differential GPS known as Carrier-Phase Differential GPS (CPDGPS) led to the development of a CPDGPS-based sensor system for automatic tractor control. With high accuracy and no drift in attitude (roll, pitch, and yaw) and/or position, CPDPGS offers a cost-effective sensor option for automatic guidance systems. Stanford researchers first experimentally demonstrated automatic steering of a medium-sized Deere 7800 tractor in the spring of 1996. Subsequent research included tractor control along spirals, arcs, and arbitrary curves, control on steeply sloped terrain, on-line identification of the steering valve’s ‘dead-zone’, and real-time identification/improvement of the tractor model. Typical controller accuracies under full engine load with implement lowered were near 0 cm mean and 4–6 cm S.D. in the tracking error of the control point on the tractor from the desired trajectory (as measured by CPDGPS). Unbiased low-noise attitude measurements were vital because the control point is not collocated with the GPS position antenna: an attitude measurement noise of only 1° (1 σ) is shown to introduce additional position uncertainty of up to 4 cm at the control point above the original GPS measurement (for a tractor of similar size to the one used in this research). In other words, accurate position information alone is not enough for a viable sensor system. These experimental results, enthusiastically received by farmers who have witnessed Stanford’s ‘GPS tractor’, show that CPDGPS could be the sole position and attitude sensor for a viable commercial tractor guidance system.