scholarly journals Design of an Experimental Workbench for Force Control Tests with Pneumatic Actuators

2018 ◽  
Author(s):  
Roberta Goergen ◽  
Marcia Regina Maboni Hoppen Porsch ◽  
Marianna Gioppo de Souza ◽  
Luiz Antônio Rasia ◽  
Antonio Carlos Valdiero
Keyword(s):  
Force Control ◽  
Pneumatic Actuators

Haptic Feedback Applied to Pneumatic Walking

2008 ◽  
Author(s):  
Brian Guerriero ◽  
Wayne Book
Keyword(s):  
Force Control ◽  
Force Feedback ◽  
Haptic Feedback ◽  
Control Method ◽  
Position Tracking ◽  
Bilateral Teleoperation ◽  
Pneumatic Actuators ◽  
Position Controller ◽  
Pressure Feedback ◽  
Foot Position

This paper presents a proposed control method for controlling the foot positions of two robotic legs through direct operator inputs with haptic feedback. The robot consists of two 3-DoF legs driven by pneumatic actuators. A demonstration of the controller shows the tracking performance enhancements of the proposed force-based position controller over a simple differential pressure gain scheduler-based position controller. The proposed controller incorporates pressure feedback to create supplementary force control. Foot position tracking remains within 10% of the commanded reference position, even through the sharp disparities of loading conditions as the actuators are either lifting the weight of the legs or supporting the weight of the robot itself. An operator gives direct foot position commands to the controller through two PHANToM haptic devices. Bilateral teleoperation of the system provides directional force feedback to the operator as a function of foot position error. The proposed controller also decreases the ambient and false forces reflected to the operator while moving the legs through gait cycles.

Multiplexed Force Control of Pneumatic Muscles

2006 ◽  
Author(s):  
V. Jouppila ◽  
A. Ellman
Keyword(s):  
High Power ◽  
Force Control ◽  
Weight Ratio ◽  
Pressure Control ◽  
Pneumatic Actuators ◽  
Pneumatic Muscle ◽  
Servo Valve ◽  
Highly Nonlinear ◽  
Muscle Actuators ◽  
Pneumatic Cylinders

Pneumatic actuators are often used in applications that require high power-to-weight ratio, combined with low price and clean and fast operation. However, due to the compressibility of air and highly nonlinear behavior of seal friction, the position and force control of these actuators is difficult to manage. As a result, pneumatic cylinders have been used for many years solely in simple repetitive tasks requiring only a very limited amount of system control. Nonetheless, the pneumatic actuators have properties such as compactness, high power-to-weight ratio, and simplicity that are desirable features in advanced robotics. To overcome the shortcomings, a number of advanced pneumatic components have been developed, of which the most promising is the pneumatic muscle. Compared to a cylinder, a pneumatic muscle not only has a higher power-to-weight and power-to-volume ratio but it is also almost frictionless and has zero leakage. In spite of the muscle actuator's nonlinear force-to-contraction characteristics, many motion and force control methods have been successfully applied to it. The characteristics of the actuator enable it to be used in simple positioning systems and as a variable gas spring. The actuator's almost linear pressure-to-force ratio is extremely well-suited to a variety of gripping and pressing applications. Due to the muscle actuator's characteristics and recent developments in pneumatic valve technology, there is an opportunity to share a single pressure control servo valve among multiple muscle actuators. The multiplexed control of the actuators with only one servo valve reduces the system costs significantly. In this paper we investigate the feasibility of employing multiplexed force control of four pneumatic muscle actuators. In the system, pressure is controlled by a single proportional pressure valve. High-speed switching valves are used for activating the pressure control for each muscle actuator in the desired manner. Pneumatic cylinders are attached to the other ends of the muscles in order to cause controllable position disturbances. The displacement, force and pressure of each muscle are measured with appropriate sensors. The system behavior is investigated under position disturbances.

scholarly journals Improvement of dynamic characteristics of manipulator driven by a gas-liquid phase-change actuator using an antagonistic drive

2018 ◽  
Vol 192 ◽  
pp. 02015
Author(s):  
Tomonori Kato ◽  
Kenya Higashijima ◽  
Yusuke Kuradome ◽  
Kohei Noguchi ◽  
Manabu Ono
Keyword(s):  
Liquid Phase ◽  
Phase Change ◽  
Dynamic Characteristics ◽  
Force Control ◽  
Control Method ◽  
Pneumatic Actuators ◽  
Research Fields ◽  
Large Size ◽  
Heat Of Evaporation ◽  
Soft Actuators

The goal of this research is to improve the dynamic characteristics of a manipulator composed of pneumatic artificial rubber muscles driven by gas-liquid phase change. Pneumatic actuators, such as pneumatic artificial rubber muscle (PARM) or rubber bellows, have been widely used in many industrial and research fields. They have merits of being compact and lightweight. However, the large size of the compressor driving the actuator is a problem. To overcome this, the authors researched soft actuators driven by the gas-liquid phase change (GLPC) of fluorocarbon. Fluorocarbon (C5F11NO) is a substance with a relatively low boiling point (50 °C) and a low heat of evaporation (104.65 kJ/kg). The heat of evaporation of water is 2260 kJ/kg. This paper presents the overview of an actuator driven by GLPC. Then, fabrication of a manipulator using the GLPC driven PARM, and details of experiments conducted to determine manipulator characteristics are given. To improve the dynamic characteristics of the manipulator, a force control method using the antagonistic drive of two PARMs is proposed, and experiments are conducted to validate the effectiveness of the proposed method.

Modeling and force control of membrane pneumatic actuators

2012 ◽  
Author(s):  
Yutaka Nojiri ◽  
Nobutaka Tsujiuchi ◽  
Takayuki Koizumi ◽  
Tomoyuki Mizuno ◽  
Yasunori Ichikawa ◽  
...  
Keyword(s):  
Force Control ◽  
Pneumatic Actuators

Modeling of Pneumatic Actuator System for High Performance Nonlinear Controller Design

2004 ◽  
Author(s):  
Meihua Tai ◽  
Ke Xu
Keyword(s):  
Force Control ◽  
High Performance ◽  
Controller Design ◽  
Pneumatic Actuator ◽  
Nonlinear Controller ◽  
Detailed Model ◽  
Pneumatic Actuators ◽  
High Bandwidth ◽  
Actuator System ◽  
Electrical Motors

Modern applications in robotics such as teleoperations and haptics require high performance force actuators. Pneumatic actuators have significant advantages over electrical motors in terms of force-to-mass ratio. However, position and force control of these actuators in applications that require high bandwidth is not trivial because of the compressibility of air and highly non-linear flow through pneumatic system components. In this paper, we develop a detailed model of a pneumatic actuator system comprised of a double acting cylinder and a proportional servo valve to be used in position, force or hybrid position and force control.

Force Control of Pneumatic Actuators Utilizing a New Pressure Estimation Technique

2011 ◽  
Author(s):  
Tad Driver ◽  
Xiangrong Shen
Keyword(s):  
Force Control ◽  
Sliding Mode ◽  
New Method ◽  
Pneumatic Cylinder ◽  
Estimation Technique ◽  
Force Output ◽  
Pneumatic Actuators ◽  
Pressure Estimation

In this paper, a new method of estimating the pressures needed to control the force output of a pneumatic cylinder is presented. A sliding mode force controller, encapsulating the dynamics of the system, is developed in order to implement and validate the pressure estimation. Experiments were conducted in order to measure the accuracy of the pressure estimation against that of the actual pressures. The results presented show that the estimated pressures accurately represent the actual pressures of the system.

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