Posts Tagged ‘Pneumatic Artificial Muscle (PAM)’

2004 – OctArm – Christopher Rahn et al (American)

Penn State Research Team Develops OctArm Soft Robot Manipulator
Recent interest in expanding the capabilities of robot manipulators has led to significant research in continuum manipulators. The idea behind these robots is to replace the serial chain of rigid links in conventional manipulators with smooth, continuous, and flexible links. Unlike traditional rigid-linked robots, continuum robot manipulators can conform to their surroundings, navigate through unstructured environments, and grasp objects using whole arm manipulation. Soft continuum manipulators can be designed with a large number of actuators to provide hyper-redundant operation that enables dexterous movement and manipulation with robust performance. This improved functionality leads to many applications in industrial, space, and defense robotics.
Previous continuum robots used cable-tendon and pressurized tube actuators with limited performance. Cable-tendons must be tensioned or the cables become snarled or fall off drive pulleys, limiting the robot speed. Pneumatic bellows have low shear stiffness, limiting load capacity. Thus, there exists a need for a highly dexterous, fast, and strong soft robot manipulators.
Dr. Christopher Rahn, Professor of Mechanical Engineering at Penn State along with his students Dustin Dienno and Mike Pritts, and assisted by Dr. Michael Grissom developed the OctArm manipulator using air muscle actuators. These actuators are constructed by covering latex tubing with a double helical weave, plastic mesh sheath to provide the large strength to weight ratio and strain required for soft robot manipulators.
OctArm is divided into three sections. Each section is capable of two axis bending and extension which allows nine degrees of freedom. The manipulators are actuated with pressurized air (Maximum pressure = 120 psi) pressure control valves and polyurethane connective tubing.
The air muscle actuators are optimized to provide the desired wrap angles and workspace. The distal section of each OctArm is designed to have a minimum wrap diameter of 10 cm. The length of each section is chosen so that the manipulator can provide a range of 360 degrees wrap angles to accommodate a wide range of objects sizes. To provide the desired dexterity, OctArm is constructed with high strain extensor actuators extend up to 80%.
To provide two-axis bending and extension, three control channels are used. selected. Six actuators are used in sections one and two and three actuators are used in section three. The six sections have two actuators for each control channel and results in actuators located at a larger radius, corresponding to higher stiffness and load capacity. Secondary layers of mesh sleeving are used to group individual actuators in control channels. Three closely-spaced actuators provide high curvature
for the distal sections. The third, visible, mesh layer or fabric skin is designed to
protect the manipulator from abrasion and wear.
For the field tests, OctArm was mounted to the second link of a Foster-Miller TALON platform. The control valves and two air tanks provided nine channels of controlled pneumatic pressure. Clemson University provided the control electronics and operation interface for these tests. The OctArm /Talon system underwent extensive field trials in the spring of 2005 at the Southwest Research Institute (SwRI) in San Antonio, Texas.
Initial tasks included stacking and unstacking traffic cones. The ability of the system to grasp objects such as spheres and cylinders over a wide range of scales was recorded. The system was also operated in water. The OctArm was submerged in water, while attempting to grasp various payloads and to maintain grasps under turbulent flow. The system was also operated in rubble piles. The trials described demonstrate that OctArm continuum robots are a feasible and attractive alternative to conventional robot manipulators in unstructured environments, and also that there is room for improvement.
To further test the robot in real-world conditions, Dr. Rahn and his post-doc, Mike Grissom, took the Talon to the Radio Park Elementary School for demonstrations in three classrooms. First, the robot was teleoperated by Dr. Grissom while Dr. Rahn introduced the students to the vehicle and the electrical, mechanical, and computer engineering required to build it. The robot “responded” to audio commands (it has a microphone). Eventually, the fifth graders guessed that the robot was teleoperated after it answered some tough true/false questions. The third graders (and some of the teachers) initially thought it was just an extremely intelligent robot. The kindergarteners treated it like a pet dog – Robbie the Robot. The students were extremely excited about the visit and even wrote thank-you letters. Many said “I want to be an engineer!”

See selected pdfs here, here, here, and here.

See other Pneumatic, Fluidic, and Inflatable robots here.

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2001-4 – MEART Rat Neuron Drawing Machine – SymbioticA (Australian/American)

SymbioticA Research Group in collaboration with The Potter Group
SymbioticA Research Group were established in 2000 as one of the core research groups in SymbloticA, the Art & Science Collaborative Research Laboratory, School of Anatomy & Human Biology, University of Western Australia. The Potter Group was established in 1999 in Los Angeles; currently operates in the Laboratory for Neuroengineering at the Georgia Institute of TechnologY, Atlanta.
        rat neurons, multi-electrode array, TCP/IP (Internet), robotic drawing arm, artificial muscles, markers and paper
        Interactive; colour
Collection: Australian Centre for the Moving Image. Courtesy the SymboticA Research Group and The Potter Group
MEART is an installation distributed between two distant locations. Its 'brain' consists of cultured nerve cells that grow and live in a neuroengineering lab at Georgia Institute of Technology, Atlanta. Its 'body' is a robotic drawing arm here at ACMI that is capable of producing 2D drawings.
For the first 13 days of the 2004 exhibition, the 'brain' and the 'body' will communicate in real time with each other. After this, MEART will draw from its digitally stored 'memories'.
MEART is assembled from: wetware – neurons from an embryonic rat cortex grown over a multi-electrode array; hardware – the robotic drawing arm; and software the interface between the wetware and the hardware. The internet is used to mediate between its components and overcome the physical distance between them. MEART suggests future scenarios where humans will manufacture intuitive and creative 'thinking entities' that have the potential to become intelligent and unpredictable beings. They may be created for anthropomorphic use, but they may not stay the way they were originally intended.
SymbioticA is an art and science collaborative research laboratory based at the School of Anatomy and Human biology at the University of Western Australia, enabling artists to undertake residencies in an environment of cutting-edge scientific research. The SymbioticA Research Group has previously exhibited Fish & Chips in ARS ElectronicA 2001. SymbioticA is also home to numerous residencies & projects including the 'Tissue Culture and Art Project', an ongoing project researching the use of tissue technologies as a medium for artistic expression.
The SymbioticA Research Group includes Guy Ben Ary, Phil Gamblen, Dr Stuart Bunt and Ian Sweetman, in collaboration with Steve M. Potter and Douglas Bakkum from The Potter Group, Georgia Institute of Technology, Atlanta.

All above images from: Reuben Hoggett personal collection.

Source: Popular Science – Oct 2003

See other Pneumatic, Fluidic, and Inflatable robots here.

1985 – McAndroid – Jon Barron et al (British)

Popular Science Jul 1985.

Humanoid? Android? Robot?
The terminology may not be well-defined, but in any event, Jon Barron, a British engineer, has dubbed his prototype anthropomorphic robot McAndroid the Android. Barron appears with his creation in the photo above.
Although he figures that the market for the manlike machine will be the entertainment industry at first, he developed McAndroid as a test-bed for new technology that could appear in robots for home or light industrial use. One possible application is the use of McAndroid's pneumatic valves, which regulate the flow and volume of air into the rolling diaphragm muscles at each of the robot's joints. The simple valve gives fine control of the android's limbs, even though the control system lacks the feedback feature found in industrial robots. Barron's fledgling company, McAndroids Ltd., is also developing software that will program the computer control in a graceful, non-jerky manner, a development that could improve the handling of delicate components on the assembly line.

[Photo of Jon Barron with McAndroid]

Popular Mechanics Aug 1985

The day of the android
The movements of robotic limbs often are stiff and halting. McAndroid the Android (right), a fusion of art and engineering, may herald a new era in robotic movement. "Mac" was developed as a sounding board for advanced manipulation technology. He is endowed with pneumatic valves which regulate the flow of air into rolling diaphragm "muscles" at each of Mac's joints.
The valve is simple, yet gives sensitive control of the android's limbs. Limb motions are key to more sophisticated industrial and home-use robots.

 [ partial extract from Robotica – Volume 8 – Issue 02 – 1990 ]

The developers say that anything can be animated by this computer-controlled air-muscle system McAndroids Ltd. (UK) has produced an 'android' robot using air-springs developed by Firestone Ltd. Three air springs were used to power each arm and to give five degrees of freedom.

Also Robotica 1987


The United Kingdom company McAndroids Ltd. of London are said to be one of the first in Europe to explore the possibilities of making the mechanical man of science fiction a reality.
The company's first android greeted visitors to the 'Robots' exhibition at the Victoria and Albert Museum in 1984 with a lifelike computer controlled body movements. Three air springs are used to power each arm, giving five degrees of freedom. The company say that the air springs are highly engineered rubber bellows made by Firestone, and powered by compressed air which is controlled by a specially designed computer-driven valve system. ENDS


Their use as robot muscles is a new development which began in 1983, soon after the introduction of Firestone's 1M1A, their newest and smallest air spring. The actuators are powered by compressed air via silicone rubber tubes running from a compressor up the interior of one leg. Fine pressure control is achieved by computer-controlled valves, designed and patented by McAndroids. The valves work on a mechanical feedback follow-up servo system which enables the arm to move smoothly to its required position, and to have a load compensation facility. Computer programs for the androids are stored on floppy discs. New sequences of movements can be either programmed from a computer terminal, or the android can be directed by a human operator using a joy-stick; the computer will remember the movements and times at the various positions and repeat them to order, running the android for extended periods without supervision.

The air springs were highly engineered rubber bellows made by Firestone Ltd.

The Modesto Bee – Mar 10, 1988

 These musicians have tin ears
The Associated Press
LONDON — A flutist with rubber lips, metal fingertips and not much else by way of physique is the latest graduate of the McAndroids laboratory in south London.
Being a robot and brand-new, it doesn't have a name yet, but its first public recitals will be given in September, when it goes on display at Taiwan's new National Museum of Natural Science.
The flutist was born in the same cluttered workshop as Tin Twin, the guest keyboard player who thrilled teen-age fans of the Thompson Twins, a British pop group, on its 1986 world tour.
Like Tin Twin, the flutist is a robotized "musician" developed by McAndroids Ltd., a special effects and 3-D animation team composed of two sculptors, a mechanical engineer and a computer artist.
McAndroids' art and technology creations have been on display since 1984 in museums, traveling exhibitions and on TV shows across Western Europe.
The flutist is going to Taichung in Taiwan along with a collection of musical instruments that visitors will be able to play without touching. Set inside glass cases, the flute, organ, tubular bells, 16-string Chinese zither and drum kit are activated by pressing buttons.
"It's very much a hands-on, discover for yourself exhibit." said sculptor Richard Glassborow. "On one level it's entertainment; on another level it's seriously stimulating."
The push buttons give spontaneous but precise control of the robotics that work the instruments. They can pluck out individual notes or create pulsating effects such as vibrato, tremolo or echo
Musical phrases, such as a bass line, can be instantly recorded and the playback accompanied by improvisation. The instruments also can he commanded to play a simple preprogrammed tune.
"It was a choice to make it simple," said Glassborow. "If you make it very rich, they (the public) just stand and look at it. We wanted to make it very friendly."
The flute's robotics are the most impressive, employing the head and pneumatically controlled fingers of a humanoid robot, or android. A valve controls the air that is pumped through the delicately positioned rubber mouthpiece into the lip plate.
The instruments took three months to build and were sold to the designers of the museum's soundproof "cacophony section" for nearly $87,000.
They demonstrate an individual's musical inventiveness and allow those without any musical skills to play music, according to Glassborow.
Tin Twin is a more readily recognizable android, with long arms that flit across the keyboard in simulating such smash hits of The Thompson Twins' as "Doctor Doctor" and "Sister of Mercy."
From a distance, the flashing lights in its eyes and mouth give the impression that it is singing along in the chorus.
McAndroids is made up of the 39-year-old Glassborow; Alan Dun, a 37-year-old sculptor; engineer Jon Barron, 34; and Trevor Piper, a 32-year-old artist. The company has found a niche in a fast-growing European market for special effects.
In 1986, its three robotic "French heads," composed of odd-shaped pieces of steel and glass fiber on top of tall poles, turned real heads at a robot sculpture display in the Georges Pompidou Center in Paris.
Vaguely resembling outer-space creatures, they turn to watch passers-by, stop and stare back, or babble among themselves in jolly jingles. A museum in Glasgow, Scotland, is negotiating for display rights.

See full patent here.
Patent number: 2133279
Filing date: Jan 3, 1936
Issue date: Oct 18, 1938

Further information is sought about McAndroid, Tin Twin, and the Flute-playing Robot. Please contact or post a comment.

1968 – Artificial Muscle Bioprosthesis – (Polish)

Modell einer Bioprothese mit künstlichem Muskel pneumatischer Art. Der Muskel besteht aus einem Gummirohr, in dessen Wände längs der Mantellinie nichtdehnbare Fäden angeordnet wurden. An den Enden sind die Gummikörper mit Endstücken zur Befestigung und Luftzuführung abgeschlossen. Beim Aufblasen des Muskels mit Druckluft verkürzt er sich und erzeugt damit eine Bewegung.

English translation

Model consists of a bioprosthesis with artificial muscle pneumatic type, the muscle of a rubber tube in the walls of which were along the generatrix of inextensible filaments arranged. At the ends of the rubber body with end pieces for fastening and air supply are completed. Shortened upon inflation of the muscle with compressed air thus producing a movement.

Source: Golems Enkel – Stefan Hesse 1988 (1986)

Bioprosthesis Robot Model

Pneumatic Bioprosthesis from Warsaw, Poland, 1968. Image source: Getty images

Further information sought on this arm. Please contact or leave a comment.

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1983 – Bridgestone “Rubbertuator” – Takeo Takagi and Yuji Sakaguchi (Japanese)

CAPTION: ROBOTS ON PARADE Keisuke Inada of Bridgestone Corp.of Tokyo adjusts the Soft Arm robot, a multijoint robot that resembles a human arm in its movements, at Cobo Hall. The Society of Manufacturing Engineers expects 25,000 people to attend its AUTOFACT '90, an exposition demonstrating computer-integrated manufacturing. Photo is dated 11/13/90.

Pneumatic actuator for manipulator Takeo Takagi et al
Patent number: 4615260
Filing date: Apr 25, 1984
Issue date: Oct 7, 1986
Japanese pat in 1983

See full patent here.

The Hybrid robot was mainly used for spray painting. Instead of being static, the arm could move sideways on a horizontal plane.

The Servo Rubbertuator Kits came with 2 pneumatic muscles, as in most cases they were to be used as an antagonistic pair i.e. each side alternatively 'pulls' as do the human muscles and joints they simulate.


Pop Sci May 1985

Rubber-armed robot
Working together in Japan, researchers at Bridgestone Corp. and Hitachi Ltd. have developed what may be the most humanoid industrial robot yet. Using novel rubber "muscles" and a rubber "hand," the new robot arm (right) can perform delicate assembly tasks. At its heart are rubber actuators that power each of the arm's seven degrees of freedom of movement.

Caption: Bridgestone's rubber actuators are used in pairs. Robot's hand moves down as bottom actuator is filled with compressed air and top one is emptied.

These actuators, shaped like sausages, behave much like human muscles, shortening and lengthening as compressed air is fed in or bled out. This linear motion, transmitted through arm to bend at its various "joints." The actuator—called the Rubbertuator- is made from a high-molecular-weight rubber tube covered with braided fiber. A flange at each end permits the entry and exit of compressed air. Bridgestone developed the rubber used in the actuator during research into long-life automobile tires. Hitachi built the arm's mechanical components. The prototype arm works under the direction of a 16-bit microprocessor, and it can lift objects weighing as much as 4.4 pounds in its simple horseshoe-shaped rubber "hand."
One of the main advantages of rubber actuators, engineers say, is that they can control not only the movement of a robot's arm but the force of that movement. Thus, rubber-armed robots can be designed to carry out the low-force tasks assigned to them but will stop should they encounter a human worker. Because the robot is pneumatic, it can be supplied by a remote air compressor, permitting installation where space is limited. Hydraulic robots, another common type, require their own bulky power supplies nearby. Bridgestone and Hitachi are now marketing their robot to companies that perform precise assembly operations using fragile components. —Stuart F. Brown

For a more complete article of the Bridgestone-Hitachi Arm see "Rubber muscles take robotics one step further" in Rubber Developments Vol 37 no 4, 1984 pdf here.

"ROBIN" – Vanderbilt University Bridgestone "Rubbertuator"-based Wall Climbing Robot.

ROBIN [ROBotic INspector] was patented September 3, 1996 in the United States (Patent Number: 5,551,525) by Robert T. Pack, Moenes Z. Iskarous, and Kazuhiko Kawamura.

Technical Description
ROBIN is a 4 DOF serial mechanism with fixtures at each end. By fixing one end of the mechanism and moving the other, ROBIN can walk, turn and transition between surfaces. ROBIN uses all off-the-shelf gears, bearings, and fittings so the system can be reproduced easily and inexpensively. ROBIN's motions are powered by Rubbertuators which are rubber pneumatic muscles that have a high strength-to-weight ratio. The pneumatic muscles and vacuum fixtures are controlled by a master-slave network of microcontrollers that continually monitor pressure, valve settings, and joint angles to keep the robot in position and on course. Chain tension of each joint is maintained by a "torque" controller. Initially, each joint's microcontroller is loaded with a table of pressures and corresponding encoder positions. Motion is achieved by applying an additive pressure, or "torque", to a rubbertuator in the desired direction of rotation. Power is provided to the robot by an umbilical cord that carries air lines, DC power, and a serial communication line for interfacing with a host computer that directs ROBIN's actions.
Advantages of ROBIN

  • High Mobility
  • Walks on planar surfaces (horizontal or vertical).
  • Transitions between horizontal and vertical surfaces, as shown in this image.
  • Steps over obstacles and gaps on surfaces.
  • Large Sensor Payload – 8Kg for prototype.
  • Scalable to Task – Design can be enlarged or miniaturized for a specific task.
  • Light Weight – 20Kg for prototype.
  • Versatile Fixtures – Handles many types of surfaces using interchangeable vacuum, magnetic, and grippers.
  • Parallel Multicontroller – Modular, extensible control system that can support fault tolerance and hot-swapping of controllers.
  • Applications of ROBIN
  • Building Inspection – Outer walls, windows, elevator shafts.
  • Aircraft Inspection – Wings, fuselage, cowling, engine mounts.
  • Ship / Tanker Inspection – Outer Hull, inner tank surfaces.
  • Bridge Inspection – Support columns, superstructure, bearings.
  • Behavior Explanation
Patent number: 5551525
Filing date: Aug 19, 1994
Issue date: Sep 3, 1996
See full patent here.

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