Design of a Biped Actuated by Pleated Pneumatic Artificial Muscles (original) (raw)
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Pleated Pneumatic Artificial Muscles for Robotic Applications
2003
This work describes the implementation of Pleated Pneumatic Artificial Muscles (PPAM) into innovative robotic applications. These actuators have a very high power to weight ratio and an inherent adaptable compliance. Two applications for which these characteristics give interesting surplus values are described. Nowadays legged robots are gaining more and more interest. But most of the robots use electrical drives making these machines heavy and power consuming. An actuator, such as the PPAM lowers the robot weight and the adaptable compliance of the muscles can be exploited to reduce energy consumption. In order to substantiate the benefits of the PPAM, a two-dimensional walking biped "LUCY" has been built. For robot manipulators, which interact with humans to support them with some heavy-duty tasks, the compliance of the PPAM can assure a "soft-touch". Moreover it is possible to estimate exerted force and torque values by measuring the applied gauge pressures in the different artificial muscles. This provides an important tool to generate manipulator force and torque feedback without expensive and complex sensor devices.
Second generation pleated pneumatic artificial muscle and its robotic applications
Advanced Robotics, 2006
This paper reports on the second generation of the Pleated Pneumatic Artificial Muscle (PPAM) which has been developed to extend the life span of its first prototype. This type of artificial was developed to overcome dry friction and material deformation which is present in the widely used McKibben type of artificial muscle. The essence of the PPAM is its pleated membrane structure which enables the muscle to work at low pressures and at large contractions. There is a growing interest in this kind of actuation for robotics applications due to its high power to weight ratio and the adaptable compliance, especially for legged locomotion and robot applications in direct contact with a human. This paper describes the design of the second generation PPAM, for which specifically the membrane layout has been changed. In function of this new layout the mathematical model, developed for the first prototype, has been reformulated. This paper gives an elaborate discussion on this mathematical model which represents the force generation and enclosed muscle volume. Static load tests on some real muscles, which have been carried out in order to validate the mathematical model, are then discussed. Furthermore are given two robotic applications which currently use these pneumatic artificial muscles. One is the biped Lucy and the another one is a manipulator application which works in direct contact with an operator.
Pneumatic muscle actuators within robotic and mechatronic systems
2015
Pneumatic artificial muscles (PAMs) as soft, lightweight and compliant actuators have great potential in applications for the actuations of new types of robots and manipulators. The favourable characteristics of fluidic muscles, such as high power-to-weight ratio and safe interaction with humans are also very suitable during the process of musculoskeletally rehabilitating patients and are often used in making artificial orthoses. This technology, despite the problems of control relatng to nonlinear phenomena, may also have wide future applications within industrial and mechatronic systems. This paper presents several experimental systems actuated by PAMs, which have been designed as test models within the fields of mobile robots, mechatronics, fluid power systems and the feedback control education of mechanical engineering students. This paper first presents the design and construction of a four legged walking robot actuated by pneumatic muscles. The robot has a fully autonomous system with a wireless application platform and can be controlled using a cell phone. Then the paper describes the design and construction of the prototype of an actively-powered ankle foot orthosis. This orthosis device actuated by a single PAM is able to provide the appropriate functions required during the rehabilitations of patients and the loss of mobility. Then the paper focuses on the design and control of a ball and beam system with an antagonistic muscle pair for generating the necessary torque for beam rotation. This mechatronic balancing mechanism falls into the category of unstable, under-actuated, multivariable systems with highly nonlinear dynamics. The final section of the article presents the design and control of a single-joint manipulator arm with pneumatic muscle actuators that enable some new features for the controlled systems.
Pleated pneumatic artificial muscles: actuators for automation and robotics
2001 IEEE/ASME International Conference on Advanced Intelligent Mechatronics. Proceedings (Cat. No.01TH8556), 2001
This contribution reports on a type of pneumatic artificial muscles (PAMs) that was recently developed at the Vrije Universiteit Brussel, department of Mechanical Engineering. Its distinguishing feature is its pleated design. Due to this, it has a very high contraction force and an equally high travel. The weight of these pleated PAMs is very low: a muscle of only 60 gr can pull up to 3500 N and contract by an amount of 42%. Furthermore, dry friction and associated hysteresis, typical of many other designs, is avoided by the folding-unfolding action. This significantly simplifies position control using these actuators. Although the force-displacement characteristics of our actuators are non-linear, they can be effectively controlled using basic linear PI techniques. Another advantage of these actuators is their inherent and controllable compliance, making them ideally suited for walking/running machines or whenever delicate tasks, e.g. handling fragile objects, have to be performed. In view of all characteristics pleated PAMs are very well suited for automation and robotic applications.
The power to weight ratio of the actuators is an important design factor for running robots. In this regard pleated pneumatic artificial muscles are excellent actuators. Another advantage is that they can actuate a joint directly, avoiding the additional weight of a gearbox. Obviously the weight of the pressure control valves has to be taken into consideration as well. For this application, standard pressure regulating valves are rather heavy and slow. An intelligently controlled array of fast switching on-off valves was tested as an alternative. Ways to decrease the opening and closing times of these valves are discussed in this paper. Simulations and experimental results will be compared. The design of a modular rotational joint with an antagonistic setup of two pleated pneumatic artificial muscles will be presented.
This paper reports on the use of a new actuator, called Pleated Pneumatic Artificial Muscle, in a one dimensional setup , it is build as a footless leg with only the knee powered by a pair of Pleated Pneumatic Artificial Muscles. The main goal of this study is the evaluation of the adaptable passive behaviour of these Artificial Muscles in a leg, which can be exploited for an energy efficient way of walking for legged robots. The new actuator and its specific advantages for the use in legged robots will be discussed as well as the concept of the one dimensional setup. It will be shown that a large amount of energy during a jump can be recuperated and continuous jumping can easily be achieved with low gauge pressures.
Control of Pneumatic Artificial Muscles with Enhanced Speed Up Circuitry
2000
The power to weight ratio of the actuators is an important design factor for running robots. Therefore pleated pneumatic artificial muscles are optimal actuators. Obviously the weight of the pressure control valves has to be taken into consideration as well. For this application, standard pressure regulating valves are rather heavy and slow. An intelligent controlled number of fast switching on-off
Control of a joint actuated by two pneumatic artificial muscles with fast switching on-off valves
The power to weight ratio of the actuators is an important design factor for running robots. In this regard pleated pneumatic artificial muscles are excellent actuators. Another advantage is that they can actuate a joint directly, avoiding the additional weight and cost of a gearbox. Obviously the weight of the pressure control valves has to be taken into consideration as well. For this application, standard pressure regulating valves are rather heavy and slow. An intelligently controlled array of fast switching on-off valves was tested as an alternative. Ways to decrease the opening and closing times of these valves are discussed in this paper. Simulations and experimental results will be compared. The design of a modular rotational joint with an antagonistic setup of two pleated pneumatic artificial muscles will be presented.
Control architecture of LUCY, a biped with pneumatic artificial muscles
2005
This paper describes the biped Lucy and it's control architecture that will be used. Lucy is actuated by Pleated Pneumatic Artificial Muscles, which have a very high power to weight ratio and an inherent adaptable compliance. These characteristics will be used to let Lucy walk in a dynamically stable manner while exploiting the adaptable passive behaviour of these muscles. A quasi-static global control has been implemented while using adapted PID techniques for the local feedback joint control. These initial control techniques resulted in the first movements of Lucy. This paper will discuss a future control architecture of Lucy to induce faster and smoother motion. The proposed control scheme is a combination of a global trajectory planner and a local low-level joint controller. The trajectory planner generates motion patterns based on two specific concepts, being the use of objective locomotion parameters, and exploiting the natural upper body dynamics by manipulating the angular momentum equation. The low-level controller can be divided in four parts: a computed torque module, an inverse delta-p unit, a local PI controller and a bang-bang controller. In order to evaluate the proposed control structure a hybrid simulator was created. Both the pneumatics and mechanics are put together in this hybrid dynamic simulation.
Actuator design using biomimicry methods and a pneumatic muscle system
Control Engineering Practice, 2006
An empirical and theoretical study is conducted on a special actuator termed ''pneumatic muscle'' (PM) being used in a force control system framework. Such an actuator has similarities to biological systems and has many advantages (extremely high power/ weight, power/volume and power/energy ratios). However, due to its inherent nonlinearities, this actuator suffers from poor position and force control. The study described here accomplishes three main goals. (1) A force control system is developed within an open and closed loop framework to emulate how biological systems work in an agonist-antagonist framework. (2) The PM used in the study has such strength that it excites the frame dynamics. This undesired dynamic response is then effectively cancelled using an impedance model control scheme. (3) The PM is demonstrated to both change length yet still produce force in a controlled manner.