scholarly journals PD Plus Dynamic Pressure Feedback Control for a Direct Drive Stewart Manipulator

Energies ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1125 ◽  
Author(s):  
Chenyang Zhang
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Dynamic Characteristics ◽  
Control Strategy ◽  
Dynamic Pressure ◽  
Control Input ◽  
Servo Motor ◽  
Direct Drive ◽  
Pressure Feedback ◽  
Current Coupling

In order to ensure good dynamic characteristics, servo valve is usually adopted as the drive part of Stewart manipulator which causes huge power consumption, while direct drive electro-hydraulic servo system has the advantages of energy saving, simple structure, convenient installation, and low failure rate. But its dynamic characteristics are so poor that it can only be applied to occasions where quick response is not needed. On the consideration above, following works are done in this paper. Since current coupling exists in the control system based on the speed of the servo motor as the control input, the control system of the direct drive Stewart manipulator is established based on the current of the servo motor as the control input in which the current coupling can be solved. In order to improve the dynamic characteristics of the direct drive Stewart manipulator, a Proportion Differentiation (PD) plus dynamic pressure feedback control strategy is also put forward in this paper, which is verified by using a simulated hydraulically driven Stewart manipulator. Simulation results show that both dynamic coupling and current coupling are solved and the control strategy proposed in this paper can significantly increase the bandwidths of all degrees of freedom.

scholarly journals Experimental Study of the Direct Drive Hydraulic System with the Torque Mode

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 941
Author(s):  
Chenyang Zhang ◽  
Hongzhou Jiang
Keyword(s):  
Transfer Function ◽  
Dynamic Characteristics ◽  
Control Strategy ◽  
Hydraulic System ◽  
Parallel Mechanism ◽  
Dynamic Pressure ◽  
Second Order ◽  
Direct Drive ◽  
Pressure Feedback ◽  
Speed Mode

The torque mode is more suitable for the direct drive 6 degree of freedom (6-DOF) parallel mechanism than the speed mode that both dynamic coupling and current coupling among motors are easily solved, but its key parameters and dynamic characteristics have never been studied, which are important and are the goals of this paper. First the hydraulic system of the direct drive 6-DOF parallel mechanism is simplified. Then the transfer function of the direct drive hydraulic system with the torque mode is deduced together with that of the speed mode. Finally, comparative experiments are conducted. Results show that the dynamic characteristics of the system with the torque mode which are generally worse than those with the speed mode, are mainly determined by the parameters of the motor-pump second-order element of the transfer function composed of two under-damped second-order elements, proportion differentiation (PD) control strategy and dynamic pressure feedback (DPF) control strategy are useful for the system with the torque mode, but practical and effective methods are still needed.

Feedback Control to Prevent Damage by Rotor Rubbing After an Impact Load

2009 ◽  
Author(s):  
Lucas Ginzinger ◽  
Benjamin Heckmann ◽  
Heinz Ulbrich
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Control Strategy ◽  
Impact Load ◽  
Operation Mode ◽  
Rotor System ◽  
Contact Forces ◽  
Normal Operation ◽  
Control Force ◽  
Auxiliary Bearing

A new approach to control a rubbing rotor by applying an active auxiliary bearing has been developed. The control force is applied indirectly using the auxiliary bearing, only in case of rotor rubbing. The auxiliary bearing is actuated using two unidirectional actuators. A three-phase control strategy has been developed which stabilizes the rotor system in case of an impact load and effectively avoids “backward whirling” which is very destructive. As soon as the load ceased the auxiliary bearing is separated from the rotor again and normal operation mode is continued. During the normal operation state, the feedback control does not interfere with the rotor system at all. A test rig has been developed to experimentally verify the control system. Various experiments show the success of the control strategy. In case of rubbing, the contact forces are reduced up to 95 percent. At the same time, the rotor deflection is decreased too. The activation and deactivation of the control system is operated fully automatically. A simulation framework for an elastic rotor including the non-smooth nonlinear dynamics of contacts is presented, which has been used to develop the feedback controller.

Control of Fuel Injection Rate for Marine Diesel Engines Using a Direct Drive Volume Control System

2015 ◽  
Author(s):  
Kazushi Sanada
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Feedback Control ◽  
Fuel Injection ◽  
Hydraulic Cylinder ◽  
Injection System ◽  
Volume Control ◽  
Direct Drive ◽  
Crank Angle ◽  
Marine Diesel

A direct drive volume control (DDVC) is applied to fuel injection control for marine diesel engine. The DDVC consists of an AC servomotor, a fixed-displacement hydraulic pump, and a hydraulic cylinder. The hydraulic cylinder pushes a plunger pump and fuel is pressurized. When the fuel pressure becomes greater than injection pressure, fuel is injected to a combustion chamber. A brief introduction of the DDVC is described first in this paper referring to conventional fuel injection systems including a cam mechanism and a common rail system. A mathematical model of the DDVC for simulation is summarized. Experiments of fuel injection shows the control function of the DDVC fuel injection system. The topic of this paper is feedback control of the quantity of fuel injection (fuel mass per injection) of the DDVC. The feedback control system is simulated using the above mathematical model. Fuel injection is stopped by switching a drive signal of the AC servomotor and retracting a piston of the hydraulic cylinder. The timing to stop injection is adjusted based on crank angle. An algorithm of updating the crank angle to stop injection is proposed so that the quantity of fuel injection follows the target value. Simulation study shows that the update algorithm works successfully.

Reduction of Quantization Error in Multirate Output Feedback Control

2016 ◽  
Vol 28 (5) ◽  
pp. 640-645
Author(s):  
Takao Sato ◽  
◽  
Hironobu Sakaguchi ◽  
Nozomu Araki ◽  
Yasuo Konishi
Keyword(s):  
Control System ◽  
Feedback Control ◽  
Output Feedback ◽  
Design Method ◽  
Output Feedback Control ◽  
Quantization Error ◽  
Design Parameters ◽  
Control Input ◽  
State Variables ◽  
Feedback Control System

[abstFig src='/00280005/04.jpg' width='250' text='Multirate output feedback control' ] In the new design method we propose for a multirate output feedback control system, the hold interval of control input is longer than the sampling interval of plant output. In this system, unknown state variables are calculated using control input and plant output without observers. The multirate output feedback control system has been extended by introducing new design parameters that are designed independent of the calculation of the state variable. To our knowledge, however, no systematic design scheme has ever been proposed for design parameters in this case. In this study, quantization error is dealt with statistically and design parameters are decided to minimize quantization error.

A Design of Current Loop for Motors Control System Based on SVPWM

2013 ◽  
Vol 433-435 ◽  
pp. 1141-1144
Author(s):  
Quan Li Han ◽  
Xi Wang
Keyword(s):  
Control System ◽  
Control Strategy ◽  
Dead Time ◽  
Motor Drive ◽  
Current Loop ◽  
Servo Motor ◽  
Current Sampling ◽  
Software And Hardware ◽  
The Dead ◽  
Dead Time Compensation

This paper introduces the SVPWM mechanism firstly and the software and hardware scheme of current loop in servo motor is designed; it also contains the control strategy and the current sampling principle. The dead time compensation problem in the inverter of the motor drive is discussed deeply. In the end, the software realization method of the interruption of current loop is presented in details.

The Design of the Pilot Type Zero Steady-State Error of Water Hydraulic Overflow Valve

2012 ◽  
Vol 233 ◽  
pp. 104-108 ◽  
Author(s):  
Li Zhang ◽  
Jing Luo ◽  
Rui Bo Yuan ◽  
Yi Bo Zhang
Keyword(s):  
Steady State ◽  
Feedback Control ◽  
Closed Loop ◽  
Constant Pressure ◽  
Dynamic Pressure ◽  
Pressure Feedback ◽  
Loop Feedback ◽  
Closed Loop Feedback ◽  
Water Hydraulic ◽  
State Error

This paper studies on its cavitation and noise problem, according to traditional pressure controlling valve has a low accuracy of constant pressure, large leakage, poor lubrication, easy corrosion and so on, designs a new structure of pilot type of water hydraulic overflow valve based on the special physicochemical properties; Detecting the inlet pressure of the main valve with the help of the micro-pressure sensor and using closed-loop feedback control and dynamic pressure feedback control to eliminate steady-state error.

The Optimization to Control System of Desulfurization in Furnace of 300MW CFB Boiler

2012 ◽  
Vol 614-615 ◽  
pp. 1509-1513
Author(s):  
Xiang Jie Kong ◽  
Jian Yun Bai ◽  
Li Hong Liu
Keyword(s):  
Control System ◽  
Power Plant ◽  
Feedback Control ◽  
Knowledge Base ◽  
Control Strategy ◽  
Transmission System ◽  
Cfb Boiler ◽  
Feedback Control Strategy

This paper contraposes 300MW CFB boiler of Shanxi certain coal-fired power plant, then optimize the control system of desulfurization and remake limestone transmission system. Collect the signal to establish knowledge base for judging starting or stalling control of feeding machine through lots of experiments. Adopt feedback control strategy to adjust the speed of feeding machine. Achieve the purpose of automatically controling the starting or stalling of feeding machine and the speed of feeding machine finally.

Feedback Linearizing Control of Surge in an Axial Compression System: Theory and Experimental Validation

1995 ◽  
Author(s):  
O. O. Badmus ◽  
S. Chowdhury ◽  
C. N. Nett
Keyword(s):  
Feedback Control ◽  
Closed Loop ◽  
Controller Design ◽  
Dynamic Pressure ◽  
Axial Compressor ◽  
State Feedback Control ◽  
Effective Length ◽  
Control Input ◽  
System Input ◽  
System Output

This paper presents experimental demonstration of surge stabilization in an axial compressor rig with a feedback linearizing controller. The controller design approach is model-based, and hence a nonlinear surge model for the facility is first validated. The surge model is a modification of the classic one-dimensional incompressible fluid surge model, with an effective length function incorporated, to account for the increased path-length of the fluid in the compressor due to the imparted tangential forces of the blade. This model, which adequately describes the observed surge dynamics both in terms of amplitude and frequency of oscillation, is then used to develop the feedback control law. The feedback linearizing control input implicitly linearizes the dynamics between the system input, throttle area parameter, and the system output, inlet dynamic pressure. A linear state feedback control input, implemented on the feedback linearized system thus ensures stabilization of the surge dynamics in the original nonlinear model. Finally, the nonlinear based observer is included in closed loop implementation to enhance the tracking of the system output, and also to minimize the adverse effect of measurement noise, thereby improving closed loop system performance.

Modeling and Control Strategy of the China LBE Cooled Fast Reactor

2014 ◽  
Author(s):  
Shoujun Yan ◽  
Zhao Wang ◽  
Pengfei Wang ◽  
Jiashuang Wan ◽  
Huawei Fang ◽  
...  
Keyword(s):  
Control System ◽  
Dynamic Characteristics ◽  
Fast Reactor ◽  
Control Strategy ◽  
Pi Controller ◽  
Primary System ◽  
Air Cooling ◽  
Feed Forward ◽  
Lead Bismuth Eutectic ◽  
And Control

China lead bismuth eutectic (LBE) cooled fast reactor comprises of the primary system with lead bismuth eutectic (LBE) as the coolant, the secondary circuit with sub-cooled water as the coolant and the associated air cooling system for an effective rejection of thermal power to the environment as a final heat sink. The dynamic characteristics of LBE cooled fast reactor are different from the traditional Pressurized Water Reactors (PWRs) because of the variances in coolant properties as well as major differences due to the operation in the fast versus the thermal neutron spectrum. To investigate the dynamic characteristics of the CLEAR-IA reactor for control system design and simulation, a model for the main components of the reactor and the most relevant interactions among them is developed. Since all the coefficients in the models are functions of temperature, the models in this paper are not described by ordinary differential equation. These models are realized by using the S-function builder of SIMULINK. The steady state calculation result based on the thermal-hydraulic models show agreement with the design value. To show the proposed models could be used for the simulation, the transient process of parameter change is compared with Relap5 simulation code, which shows agreement. A Proportional-Integral (PI) controller is designed to keep the power following the set value as quickly as possible. To keep the inlet temperature of core coolant constant, a control strategy based on a simultaneous feed-forward and feedback scheme has been adopted. The feed-back control system is a PI controller and it can achieve a real time and no error control, but it has time delay. The feed-forward control can realize the control in advance before the LBE temperature at inlet of the core has been changed to reduce the overshoot. So the feed-forward can realize an advance and rough control, the feedback can realize a no error and accurate control. Based on the developed model and control strategy, dynamic simulations of the whole system in case of step changes of reactivity and set power are performed. The simulation results show that the proposed model is accurate enough to describe the dynamic behaviors of the plant in spite of its simplicity. It has also been demonstrated that the developed controllers for the CLEAR-IA can provide superior reactor control due to the efficiency of the control strategy adopted.

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