Research on the performance of a novel electro-hydraulic proportional directional valve with position-feedback groove

2021 ◽  
pp. 095440892110244
Author(s):  
Ruihao Zhao ◽  
Yaoyao Liao ◽  
Zisheng Lian ◽  
Runze Li ◽  
Yongchang Guo
Keyword(s):  
Simulation Model ◽  
Control Method ◽  
Response Speed ◽  
Research Direction ◽  
Posture Control ◽  
Chamber Pressure ◽  
Inlet Valve ◽  
Pressurized Water ◽  
Proportional Directional Valve ◽  
Roof Support

Accurate posture control of hydraulic roof supports, which use pressurized water as their fluid power source, is an important part and research direction of intelligent fully mechanized mining face. At present, the large flow on/off directional valve used on the hydraulic roof support cannot meet the requirement of precise posture control of the roof support. To overcome the conundrum, a novel two-position three-way electro-hydraulic proportional directional flow valve for hydraulic roof support is proposed. The new valve contains two pilot stages and two main spools. The two pilot stages cooperate with each other to control the movement of the two main valve spools, which are the inlet valve spool and the outlet valve spool. The inlet valve spool adopts the Valvistor principle. The valve can realize manual pilot control and electro-hydraulic proportional flow control of the passage P-A, which has been verified by a simulation model. In this paper, the static and dynamic mathematical models of the new proportional valve are established, and the key parameters affecting the valve performances are analyzed and verified by the simulation model. An optimization control scheme is proposed to overcome the influence of supply pressure, P-A pressure difference, and nonlinear interference force on steady-state displacement and response speed of the valve. The results show that this optimization method can significantly improve the response speed of the spool and promote the linearity of spool displacement under a slope signal. In addition, the fluctuation of chamber pressure and spool displacement caused by the discontinuous flow of a fast switching valve is systematically analyzed. The analysis shows that increasing pulse-width modulation carrier frequency is an effective way to reduce fluctuation amplitude. The research provides a new design idea and control method for an electro-hydraulic proportional directional valve of hydraulic roof support.

Constant force control for aluminum wheel hub grinding based on ESO + backstepping

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shijie Dai ◽  
Yufeng Zhao ◽  
Wenbin Ji ◽  
Jiaheng Mu ◽  
Fengbao Hu
Keyword(s):  
Control Strategy ◽  
Force Control ◽  
Control Method ◽  
Response Speed ◽  
Backstepping Control ◽  
Constant Force ◽  
Content Type ◽  
Disturbance Rejection Control ◽  
The Stability ◽  
Differential Control

Purpose This paper aims to present a control method to realize the constant force grinding of automobile wheel hub. Design/methodology/approach A constant force control strategy combined by extended state observer (ESO) and backstepping control is proposed. ESO is used to estimate the total disturbance to improve the anti-interference and stability of the system and Backstepping control is used to improve the response speed of the system. Findings The simulation and grinding experimental results show that, compared with the proportional integral differential control and active disturbance rejection control, the designed controller can improve the dynamic response performance and anti-interference ability of the system and can quickly track the expected force and improve the grinding quality of the hub surface. Originality/value The main contribution of this paper lies in the proposed of a new constant force control strategy, which significantly improved the stability and precision of grinding force.

Research on automobile four-wheel steering control system based on yaw angular velocity and centroid cornering angle

2021 ◽  
pp. 002029402110354
Author(s):  
Yifeng Zhang ◽  
Zhiwen Wang ◽  
Yuhang Wang ◽  
Canlong Zhang ◽  
Biao Zhao
Keyword(s):  
Optimal Control ◽  
Feedback Control ◽  
High Speed ◽  
Control Method ◽  
Response Speed ◽  
State Feedback Control ◽  
Steering Control ◽  
Yaw Rate ◽  
Simulink Simulation ◽  
Optimal Control Method

In order to improve the handling stability of four-wheel steering (4WS) cars, a two-degree-of-freedom 4WS vehicle dynamics model is constructed here, and the motion differential equation of the system model is established. Based on the quadratic optimal control theory, the optimal control of 4WS system is proposed in this paper. When running at low speed and high speed, through yaw rate feedback control, state feedback control, and optimal control, the 4WS cars are controlled based on yaw rate and centroid cornering angle with MATLAB/Simulink simulation. The result indicates that 4WS control based on the optimal control can improve the displacement of the cars. And, the optimal control of 4WS proposed in this paper can eliminate centroid cornering angle completely compared with other two traditional optimal control methods. Besides, the optimal control enjoys faster response speed and no overshoot happens. In conclusion, the optimal control method proposed in the paper represents better stability, moving track and stability, thereby further enhancing the handling property of cars.

Commutation Loss in Hydrostatic Pumps and Motors

2021 ◽  
Author(s):  
Robin Mommers ◽  
Peter Achten ◽  
Jasper Achten ◽  
Jeroen Potma
Keyword(s):  
Experimental Data ◽  
Energy Loss ◽  
Simulation Model ◽  
Operating Conditions ◽  
Chamber Pressure ◽  
Working Mechanism ◽  
Working Chamber ◽  
Lumped Parameter ◽  
Long Time ◽  
Pressure Changes

Abstract In mobile hydraulic applications, more efficient machinery generally translates to smaller batteries or less diesel consumption, and smaller cooling solutions. A key part of such systems are hydrostatic pumps and motors. While these devices have been around for a long time, some of the causes of energy loss in pump and motors are still not properly defined. This paper focuses on one of the causes of energy loss in pumps and motors, by identifying the energy loss as a result of the process of commutation. By nature, all hydrostatic pumps and motors have some form of commutation: the transition from the supply port to the discharge port of the machine (and vice versa). During commutation, the connection between the working chamber and the ports is temporarily closed. The chamber pressure changes by compression or decompression that is the result of the rotation of the working mechanism. Ideally, the connection to one of the ports is opened once the chamber pressure equals the port pressure. When the connection is opened too early or too late, energy is lost. This paper describes a method to predict the commutation loss using a lumped parameter simulation model. To verify these predictions, experimental data of a floating cup pump was compared to the calculated values, which show a decent match. Furthermore, the results show that, depending on the operating conditions, up to 50% of all losses in this pump are caused by improper commutation.

FRACTURE HEALING SIMULATION REGULATED BY FORCE AND OXYGEN

2019 ◽  
Vol 19 (07) ◽  
pp. 1940029
Author(s):  
MONAN WANG ◽  
XINYU WANG ◽  
QIYOU YANG
Keyword(s):  
Simulation Model ◽  
Fracture Healing ◽  
Control Method ◽  
Mechanical Stability ◽  
Healing Process ◽  
Tissue Differentiation ◽  
Simulation Program ◽  
Spatial And Temporal Variation ◽  
Oxygen Levels ◽  
Axial Stability

According to the mechanical conditions of fracture fixation and the oxygen levels in the tissues, a simulation model of fracture healing process was built to describe the relationship among mechanical stability, oxygen levels in tissues and tissue differentiation during the second fracture healing. Different from the previous simulation model, in this paper, we took the three-dimensional model as the research object, solved the mechanical stimulation by finite element method, established the partial differential equation to solve the spatial and temporal variation of the oxygen in tissues. The process of tissue differentiation was described by fuzzy control method. The initial stage of fracture healing, intramembranous ossification, chondrogenesis, cartilage calcification and endochondral ossification during the fracture healing process were simulated, and the properties of tissue materials were continuously updated to complete the iterative process. The simulation program of fracture healing process was independently developed in Eclipse environment, and the simulation results were compared with experimental data and those of other fracture healing simulation models to verify the simulation program in this paper. Finally, the processes of transverse fracture healing in rats with different axial stability under normoxic, hypoxic and hyperoxic conditions was simulated, and the effects of different tissue oxygen levels and interosseous stabilities on fracture healing were analyzed. It is concluded by simulation that the delayed healing or non-union of bone will occur when in state of tissue hypoxia or interosseous instability, normal healing will occur when in state of tissue normoxia, and the healing will be accelerated when in state of tissue hyperoxia.

Model predictive torque control of a six-phase PM synchronous hub motor with auxiliary voltage vectors

2020 ◽  
pp. 1-17
Author(s):  
Hao Xu ◽  
Long Chen ◽  
Xiaodong Sun
Keyword(s):  
Permanent Magnet ◽  
Electric Vehicles ◽  
Control Method ◽  
Research Direction ◽  
Synchronous Motor ◽  
Torque Control ◽  
Experimental Results ◽  
Vector Model ◽  
Dynamic State ◽  
Three Phase

Permanent magnet synchronous hub motors (PMSHMs) have been gradually introduced into the applications of electric vehicles. In order to output more torque, many researchers turned their research direction to six-phase motors. Because it is composed of two sets of three-phase windings, there will be interference between the windings, affecting the performance of the motor. In order to improve the steady and dynamic-state performance of permanent magnet six phase synchronous motor, a predictive torque control method based on multi vector model is proposed in this paper. Finally, experimental results show the effectiveness of this method.

scholarly journals Research on the Posture Control Method of Hexapod Robot for Rugged Terrain

2020 ◽  
Vol 10 (19) ◽  
pp. 6725
Author(s):  
Yubin Liu ◽  
Chunbo Wang ◽  
He Zhang ◽  
Jie Zhao
Keyword(s):  
Control Method ◽  
Posture Control ◽  
Rough Terrain ◽  
Maintenance Strategy ◽  
Hexapod Robot ◽  
Rugged Terrain ◽  
Foot Force ◽  
Adjustment Strategy ◽  
Posture Maintenance ◽  
Posture Adjustment

This paper proposes a hexapod robot posture control method for rugged terrain to solve the problem of difficulty in realizing the posture control of a foot robot in rough terrain. The walking gait and original position of a six-legged robot is planned, and the Layer Identification of Tracking (LIT) strategy is developed to enable the robot to distinguish mild rugged terrain and severe rugged terrains automatically. The virtual suspension dynamic model is established. In mild rugged terrain, the posture maintenance strategy is adopted to keep the stability of the torso. In severe rugged terrain, the posture adjustment strategy is adopted to ensure the leg workspace and make it more widely adapt to the changing terrain, and a gravity center position adjustment method based on foot force distribution is designed to use foot force as feedback to control the position and attitude. The experiment of posture control in rough terrain and climbing experiment in the ladder terrain shows that the hexapod robot has good posture maintenance and posture adjustment effects when traversing complex terrain through the posture maintenance strategy and the posture adjustment strategy. Combined with the terrain identification method based on LIT, the hexapod robot can successfully climb the ladder terrain through the identification of the changing ladder terrain, and the movement of the posture adjustment process is stable.

scholarly journals Underactuated robotics: A review

2019 ◽  
Vol 16 (4) ◽  
pp. 172988141986216 ◽  
Author(s):  
Bin He ◽  
Shuai Wang ◽  
Yongjia Liu
Keyword(s):  
Control Method ◽  
Constraint Equation ◽  
Research Direction ◽  
Control Flow ◽  
Future Research ◽  
Control Input ◽  
Research Directions ◽  
Loop Control ◽  
Future Research Directions ◽  
Underactuated Robot

Underactuated robotics is an emerging research direction in the field of robotics. The control input of the underactuated robot is less than the degree of freedom of the system. It has the advantages of lightweight, low energy consumption, excellent performance, and broad development prospects. This article reviews the state of the art on underactuated robotics. On the basis of previous studies, this article takes the non-holonomic constraint equation as the entry point to classify and summarize underactuated robot and their common mechanisms. The controllability of underactuated robot is further discussed. The control flow of underactuated robot is described based on the open–closed control method. In the closed-loop control, the control method based on the fuzzy system is mainly used. Finally, the difficulties in the current research of underactuated robot are summarized, and the future research directions are prospected.

Recent Study on the Passive and Active Vibration Isolators

2014 ◽  
Vol 494-495 ◽  
pp. 491-496
Author(s):  
Hua Ping Mei ◽  
Hao Yue Tian ◽  
Shuan Huang
Keyword(s):  
Vibration Isolation ◽  
Control Method ◽  
Low Frequency ◽  
Research Direction ◽  
Magnetic Suspension ◽  
High Frequency Oscillation ◽  
Future Research ◽  
Vibration Isolator ◽  
Vibration Isolators ◽  
Active Vibration

The vibration isolators have witnessed significant developments due to pressing demands for high resolution metrology and manufacturing, optical, physical and chemical experiments. In the view of these requirements, the engineers and physicists have exploited different types of vibration isolators. This paper firstly presents the recent developments on the passive vibration isolators. It finds that the passive vibration isolators can constrain the high frequency oscillation. The active control is the efficient method to cancel the low frequency vibration. Then, the paper is concerned with the recent advances on the active vibration isolator. The appropriate actuator, sensor and advanced control method are the key component of the active vibration isolator to enhance their vibration isolation properties. Finally, the author proposes that the magnetic suspension vibration isolator is a future research direction in the field of the vibration isolation.

Sign in / Sign up

Export Citation Format

Share Document