Accurate Position Control of a Pneumatic Actuator

1990 ◽  
Vol 112 (4) ◽  
pp. 734-739 ◽  
Author(s):  
Jiing-Yih Lai ◽  
Chia-Hsiang Menq ◽  
Rajendra Singh
Keyword(s):  
Control Strategy ◽  
Pulse Width Modulation ◽  
Position Control ◽  
Integral Control ◽  
Pneumatic Actuators ◽  
Actuator Dynamics ◽  
Position Accuracy ◽  
Modulation Mode ◽  
Nonlinear Mechanical ◽  
Accurate Position

We propose a new control strategy for on-off valve controlled pneumatic actuators and robots with focus on the position accuracy. A mathematical model incorporating pneumatic process nonlinearities and nonlinear mechanical friction has been developed to characterize the actuator dynamics; this model with a few simplifications is then used to design the controller. In our control scheme, one valve is held open and the other is operated under the pulse width modulation mode to simulate the proportional control. An inner loop utilizing proportional-plus-integral control is formed to control the actuator pressure, and an outer loop with displacement and velocity feedbacks is used to control the load displacement. Also, a two staged feedforward force is implemented to reduce the steady state error due to the nonlinear mechanical friction. Experimental results on a single-degree-of-freedom pneumatic robot indicate that the proposed control system is better than the conventional on-off control strategy as it is effective in achieving the desired position accuracy without using any mechanical stops in the actuator.

scholarly journals Study of Nonlinear Characteristics and Model Based Control for Proportional Electromagnet

2018 ◽  
Vol 2018 ◽  
pp. 1-11
Author(s):  
En-Zhe Song ◽  
Guo-Feng Zhao ◽  
Chong Yao ◽  
Zi-Kun Ma ◽  
Shun-Liang Ding ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Control Strategy ◽  
Position Control ◽  
Tracking Performance ◽  
Experimental Investigations ◽  
Position Tracking ◽  
Hysteresis Phenomenon ◽  
Nonlinear Characteristics ◽  
Model Control ◽  
Accurate Position

The nonlinear characteristics of proportional electromagnet caused by hysteresis bring great difficulties on its accurate position tracking control by current. In order to enhance the practicability and reliability of long stroke electromagnet in case of position sensor fault and improve the position tracking performance during current closed-loop control, experimental investigations on the electromagnet actuator hysteresis characteristics of diesel engine governor are carried out to analyze the system dynamic features and the effects of hysteresis on actuator position tracking performance. It is clear that hysteresis can significantly hinder the accurate position control of the electromagnet actuator. Consequently, the fuel injection will be delayed, which will lead to hysteresis of engine speed control as well as deterioration of engine performance. In this paper, the hysteresis phenomenon of an actuator and its influence on control performance of engine are investigated. The model of proportional electromagnet actuator (PEA) is established and the hysteresis principle is analyzed. Then the inverse model control strategy based on neural network (NN) is proposed to linearize the transfer behavior of electromagnet and compensate for the magnet hysteresis. Rapid control prototyping (RCP) experiment based on MicroAutoBox is further implemented to validate the real-time performance of the proposed control strategy in D6114 diesel engine. The results show that the speed fluctuation (SF) under steady-state conditions (especially under idle speed condition) and the recovery time as well as the overshoot under transient conditions are significantly improved. This makes it possible to develop redundant electromagnet driving control strategy.

Control of Pneumatic Robots Using Variable Offset Pressure Controller

2011 ◽  
Vol 23 (6) ◽  
pp. 1024-1030 ◽  
Author(s):  
Naoki Igo ◽  
◽  
Kiyoshi Hoshino
Keyword(s):  
Rise Time ◽  
Control Algorithm ◽  
Position Control ◽  
Quick Response ◽  
Pd Controller ◽  
Tracking Accuracy ◽  
Pneumatic Actuators ◽  
Accurate Position ◽  
Pressure Controller ◽  
Proportional Controller

We proposed a control algorithm for pneumatic actuators which can realize accurate position control. Specifically, the controller achieves quick response and less overshoot using the conventional proportional controller (P-controller) with an offset pressure controller which may increase or decrease the rigidity to the pneumatic actuators. The experimental results showed that a rise time was almost the same as that of the conventional PD controller but a tracking accuracy was improved when the lamp input was given as the target.

scholarly journals Position Control of Pneumatic Actuators Using Three-Mode Discrete-Valued Model Predictive Control

Actuators ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 56 ◽  
Author(s):  
Haitao Qi ◽  
Gary M. Bone ◽  
Yile Zhang
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Pulse Width Modulation ◽  
Performance Metrics ◽  
Position Control ◽  
Sliding Mode ◽  
Absolute Error ◽  
Switching Frequency ◽  
Pneumatic Actuators ◽  
Clear Winner

A novel discrete-valued model-predictive control (DVMPC) algorithm termed DVMPC2 for the position control of pneumatic actuators using inexpensive on/off valves is presented. DVMPC2 includes a more flexible cost function, an improved prediction strategy, and other improvements. The actuator is a double-acting cylinder with two on/off solenoid poppet valves connected to each chamber. To reduce the switching frequency and prolong the valve life, DVMPC2 directly switches the valves when necessary, instead of using relatively high-frequency pulse-width modulation. Experimental comparisons are made with the state-of-the-art sliding-mode control (SMC) algorithm and the previous DVMPC algorithm. The comparisons are based on the five performance metrics: integral of time-weighted absolute error (ITAE), root mean square error (RMSE), overshoot (OS), steady-state error (SSE), and valve switches per second (SPS). The robustness is evaluated by increasing and decreasing the total mass of the moving components while keeping the controller parameters constant. The experimental results show that the proposed algorithm is superior to the previous DVMPC and outperformed SMC by a wide margin. Specifically, DVMPC2 reduced ITAE by 80%, RMSE by 52%, OS by 43%, and SPS by 20% relative to SMC. There was no clear winner in terms of SSE.

The Intelligent Learning Control on Slide Position of Mechanical Crank Press

2009 ◽  
Author(s):  
Hong Zhao ◽  
Shengdun Zhao
Keyword(s):  
Control Strategy ◽  
Iterative Learning Control ◽  
Position Control ◽  
Expert Knowledge ◽  
Computer Control ◽  
Learning Control ◽  
Computer Control System ◽  
The Press ◽  
Mechanical Press ◽  
Accurate Position

An iterative learning control strategy based on the expert knowledge is proposed in the slide position control of the mechanical press. The slide can be stopped on an accurate position at any point of the slide travel. The proposed strategy is more efficiency and accurate than the original inching operation method. A new computer control system is developed for the mechanical press. Experimental results are shown that the proposed control strategy on the press JH23-63 is effective.

Accurate Position Control for Hydraulic Servomechanisms

2019 ◽  
Author(s):  
Manuel Pencelli ◽  
Renzo Villa ◽  
Alfredo Argiolas ◽  
Gianni Ferretti ◽  
Marta Niccolini ◽  
...  
Keyword(s):  
Position Control ◽  
Accurate Position

scholarly journals Correction to: Accurate position control of shape memory alloy actuation using displacement feedback and self-sensing system

2021 ◽  
Author(s):  
Ermira Junita Abdullah ◽  
Josu Soriano ◽  
Iñaki Fernández de Bastida Garrido ◽  
Dayang Laila Abdul Majid
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Position Control ◽  
Sensing System ◽  
Accurate Position

Performance Improvement of SVPWM-Based Three-Phase Grid-Connected Inverters

2013 ◽  
Vol 732-733 ◽  
pp. 1261-1264
Author(s):  
Zhi Lei Yao ◽  
Lan Xiao ◽  
Jing Xu
Keyword(s):  
Dynamic Response ◽  
Control Strategy ◽  
Pulse Width Modulation ◽  
Control Method ◽  
Grid Current ◽  
Current Controller ◽  
Three Phase ◽  
Reference Grid ◽  
Grid Connected Inverter

An improved control strategy for three-phase grid-connected inverters with space vector pulse width modulation (SVPWM) is proposed. When the grid current contains harmonics, the d-and q-axes grid currents is interacted in the traditional control method, and the waveform quality of the grid current is poor. As the reference output voltage cannot directly reflect the change of the reference grid current with the traditional control strategy, the dynamic response of the grid-connected inverter is slow. In order to solve the aforementioned problems, the d-and q-axes grid currents in the decoupled components of the grid current controller are substituted by the d-and q-axes reference grid currents, respectively. The operating principles of the traditional and proposed control methods are illustrated. Experimental results show that the grid-connected inverter with the improved control strategy has high waveform quality of the grid current and fast dynamic response.

Optimized Non-Dead-Time Control of Inverter with Two-Phase Modulated SVPWM

2012 ◽  
Vol 562-564 ◽  
pp. 1531-1536
Author(s):  
Ming Xing Zhu ◽  
Jing Bo Shi
Keyword(s):  
Control Strategy ◽  
Pulse Width Modulation ◽  
Dead Time ◽  
Control Method ◽  
Short Circuit ◽  
Two Phase ◽  
Zero Crossing ◽  
Time Control ◽  
Bus Voltage ◽  
Current Zero

In the inverter control system, two-phase modulated space vector pulse width modulation (SVPWM) algorithm has the advantages of minimum switch loss and higher utilization of direct current (DC) bus voltage. Non-dead-time control strategy can eliminate the problems of the dead time effects. But the traditional non-dead-time control strategy heavily depends on the current zero-crossing detection, which may cause the output voltage distortion or even a short circuit. Based on the analysis of the reason for the distortion, a new optimized non-dead-time control method is proposed. Two methods for the detection of the overlapping area are enumerated. The conclusions are confirmed by the simulation results with MATLAB/ SIMULINK.

Collaborative Tracking Control Strategy for Autonomous Excavation of a Hydraulic Excavator

2021 ◽  
Vol 10 (1) ◽  
pp. 43
Author(s):  
Fattah Hanafi Sheikhha ◽  
Ali Afzalaghaeinaeini ◽  
Jaho Seo
Keyword(s):  
Control Strategy ◽  
Tracking Control ◽  
Position Control ◽  
Simulation Models ◽  
Hydraulic Excavator ◽  
Tracking Errors ◽  
Collaborative Tracking ◽  
Autonomous Excavation ◽  
Tip Position ◽  
Electrohydraulic Actuators

A hydraulic excavator consists of multiple electrohydraulic actuators (EHA). Due to uncertainties and nonlinearities in EHAs, it is challenging to devise a proper control strategy. To tackle this issue, a major goal of our study is to provide an efficient control strategy to minimize tracking errors of the bucket tip position for autonomous excavation. To accomplish the goal, the study offers a collaboration of PID and fuzzy controllers that are used to compensate for contour errors and achieve accurate actuator position control, respectively. Co-simulation models including control algorithms and hydraulic components were created using Matlab and Amesim to validate the performance of the designed controllers. Simulations indicate that the proposed method enables achieving accurate tracking control for autonomous excavation with small tracking errors despite the nonlinear characteristics of the hydraulic excavator system.

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