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.

Control of Air Cylinder Actuator with Common Bias Pressure

2011 ◽  
Vol 23 (6) ◽  
pp. 991-998
Author(s):  
Kiyoshi Hoshino ◽  
◽  
Weragala Don Gayan Krishantha
Keyword(s):  
Pid Controller ◽  
Control Algorithm ◽  
Position Control ◽  
Pressure Control ◽  
Elderly Persons ◽  
Quick Response ◽  
Pd Controller ◽  
Passive Stiffness ◽  
Simple Method ◽  
Bias Pressure

In this study, we propose a control algorithm for a pneumatic actuator that has dynamics and features similar to those of the human muscle, mainly with the aim of helping elderly persons communicate. The algorithm in this study can estimate gains by using a simple method with a double-acting air cylinder and can realize accurate speed control and position control. Specifically, we aimed to achieve quick response and less overshoot by providing a PD controller for common bias pressure control, that can generate passive stiffness, in addition to a PID controller capable of controlling disturbance and target tracking without any complicated control system. We performed gain estimation by first theoretically estimating the PID gain and then determining the optimum PD gain by actually moving an air cylinder. We tried controlling a system consisting of one air cylinder and a solenoid valve and found that the overshoot, which was nearly 30% with only the PID controller, was controlled to 4%, while the rise time was less than 200 ms of that when only the PID controller was used.

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.

Backward-Euler Discretization of Second-Order Sliding Mode Control and Super-Twisting Observer for Accurate Position Control

2013 ◽  
Author(s):  
Xiaogang Xiong ◽  
Ryo Kikuuwe ◽  
Motoji Yamamoto
Keyword(s):  
Sliding Mode Control ◽  
Control Algorithm ◽  
Position Control ◽  
Sliding Mode ◽  
Second Order ◽  
Mode Control ◽  
Backward Euler ◽  
Euler Discretization ◽  
Accurate Position ◽  
Second Order Sliding Mode

This paper introduces an accurate position control algorithm based on Backward-Euler discretization of a second-order sliding mode control (SOSMC) and the super-twisting observer (STO). This position control algorithm does not produce numerical chattering, which has been known to be a major drawback of explicit implementation of SOSMC and STO. It is more accurate than the conventional PID control that is also free of chattering. In contrast to conventional Backward-Euler discretization schemes of SOSMC and STO, the presented discretization method does not require any special solvers for computation. The accuracy and implementation of this algorithm are illustrated by simulations.

Simulation and Implementation of Multiple Unipolar Stepper Motor Position Control in the Three Stepping Modes using Microcontroller

2016 ◽  
Vol 4 (1) ◽  
pp. 29
Author(s):  
Ayman Y. Yousef ◽  
M. H. Mostafa
Keyword(s):  
Control System ◽  
Software Package ◽  
Control Algorithm ◽  
Position Control ◽  
Low Cost ◽  
Open Loop ◽  
Stepper Motor ◽  
Stepper Motors ◽  
Accurate Position ◽  
Position Control System

<p>This paper presents a multiple unipolar stepper motor position control system using microcontroller (MCU) in anticlockwise and clockwise directions. The open loop controller of the implemented position control system for the three stepping modes of operation has been designed and developed with three stepper motors and without position feedback. The MCU is programmed using flowcode software package to generate the pulse signals with the desired stepping sequences and step angles. These pulse signals are necessary to drive the three stepper motors in the three drive modes (wave-step, full-step, and Half-step) according to the control algorithm. Three devices of 8 Channel Darlington Driver (chip ULN2803) are used to drive the three stepper motors and provide them with the sufficient current. The position control system has been simulated using proteus design suite software package and the controller has been implemented using low cost PIC16F877A (MCU). A reliable and accurate position control of the stepper motor is achieved by this position control system. </p>

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

scholarly journals Force-Free Control for Direct Teaching of a Surgical Assistant Robot End Effector with Wire-Driven Bidirectional Telescopic Mechanism

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3498
Author(s):  
Youqiang Zhang ◽  
Cheol-Su Jeong ◽  
Minhyo Kim ◽  
Sangrok Jin
Keyword(s):  
Control Algorithm ◽  
Position Control ◽  
Friction Model ◽  
Surgical Instruments ◽  
Control Input ◽  
End Effector ◽  
Motor Current ◽  
Direct Teaching ◽  
End Effectors ◽  
Teaching Operation

This paper shows the design and modeling of an end effector with a bidirectional telescopic mechanism to allow a surgical assistant robot to hold and handle surgical instruments. It also presents a force-free control algorithm for the direct teaching of end effectors. The bidirectional telescopic mechanism can actively transmit force both upwards and downwards by staggering the wires on both sides. In order to estimate and control torque via motor current without a force/torque sensor, the gravity model and friction model of the device are derived through repeated experiments. The LuGre model is applied to the friction model, and the static and dynamic parameters are obtained using a curve fitting function and a genetic algorithm. Direct teaching control is designed using a force-free control algorithm that compensates for the estimated torque from the motor current for gravity and friction, and then converts it into a position control input. Direct teaching operation sensitivity is verified through hand-guiding experiments.

scholarly journals Neural Network Based Contact Force Control Algorithm for Walking Robots

Sensors ◽  
2021 ◽  
Vol 21 (1) ◽  
pp. 287
Author(s):  
Byeongjin Kim ◽  
Soohyun Kim
Keyword(s):  
Neural Network ◽  
Contact Force ◽  
Force Control ◽  
Control Algorithm ◽  
Position Control ◽  
Linear Quadratic Regulator ◽  
Walking Robots ◽  
Test Model ◽  
Linear Quadratic ◽  
Contact Force Control

Walking algorithms using push-off improve moving efficiency and disturbance rejection performance. However, the algorithm based on classical contact force control requires an exact model or a Force/Torque sensor. This paper proposes a novel contact force control algorithm based on neural networks. The proposed model is adapted to a linear quadratic regulator for position control and balance. The results demonstrate that this neural network-based model can accurately generate force and effectively reduce errors without requiring a sensor. The effectiveness of the algorithm is assessed with the realistic test model. Compared to the Jacobian-based calculation, our algorithm significantly improves the accuracy of the force control. One step simulation was used to analyze the robustness of the algorithm. In summary, this walking control algorithm generates a push-off force with precision and enables it to reject disturbance rapidly.

Experimental Investigation Into Improved Wrapper Control of Hot Strip Steel Rolling Mill Downcoilers

2009 ◽  
Author(s):  
D. Ll. Davies ◽  
J. Watton ◽  
Y. Xue ◽  
G. A. Williams
Keyword(s):  
Rolling Mill ◽  
New Technologies ◽  
Position Control ◽  
Steel Production ◽  
Rolling Process ◽  
Steel Rolling ◽  
Hot Strip ◽  
Accurate Position ◽  
Manufacturing Techniques ◽  
Coiling Process

With increasing international competition in steel production mainly from developing nations, it is important for steel plants to keep up to date with new technologies, and continuously improve on current practices and manufacturing techniques to remain competitive. This paper looks specifically at improvements to the hot rolling mill downcoilers, which is where the strip is coiled at the end of the rolling process. Hydraulic and pneumatic technology is combined to give accurate position control of guide wrappers that aid the initial coiling process. The paper presents an experimental test rig, using an actual wrapper guide, constructed to evaluate the specific design approach.

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