CANADARM – End to end mobile robotic arm

The Development of Legend…

Canada’s most famous robotic and technological achievement made its space debut on November 13, 1981. The design and building of the Shuttle Remote Manipulator System marks the beginning of Canada’s close collaboration with NASA in manned space flight. The Canadarm project remains a sterling example of successful international space cooperation.
Canadarm firmly established Canada’s international reputation for robotics innovation and know-how. Its excellent performance record has inspired several generations of scientists and engineers as they develop new technologies for industry, medicine, and other applications .

The Structure of CANADARM…

  • Canadarm, the Shuttle Remote Manipulator System (SRMS), is a remote-controlled, payload-handling device made up of a number of components:

1) Joints
2) Wiring harness
3) Closed circuit televisions
4) Thermal protection system
5) Booms
6) End effectors
7) SRMS control system

1) Joints.

Each subassembly component of the SRMS is made up of a basic element called a joint one-degree-of-freedom or JOD.
There are two JODs in the shoulder joint, which allow the whole arm to pitch and yaw.
There is another JOD in the elbow joint to allow the lower arm to pitch. Three more JODs in the wrist joint allow the tip of the arm to pitch, yaw and roll.
The SRMS can move even more freely than the human arm to accomplish very complex man oeuvres.
Each JOD also incorporates a device called an encoder, which accurately measures joint angles.

CANADARM joints

CANADARM joints

2) BOOMS.

Between the shoulder, elbow and wrist joints are the upper and lower booms constructed of graphite-epoxy.
The upper arm boom is about 5 meters long and 33 centimeters in diameter. It’s made up of 16 plies of graphite-epoxy and weights about 23 kilograms.
The lower arm boom is about 5.8 meters long by 33 centimeters in diameter, made up of 11 plies of graphite-epoxy and weights about 22.7 kilograms.
Each boom is protected with a Kevlar bumper to prevent dents or scratches on the carbon composite.

CANADARM booms

CANADARM booms

3) Wiring Harness

The wiring harness provides electrical power to all the joints and the end effector (the mechanical hand) as well as data and feedback information from each of the joints. This link goes from the SRMS in the payload bay and continues back into the cabin of the Space Shuttle where astronauts control the actions of the arm remotely.

4) End Effectors.

In place of a hand, the Canadarm has a cylindrical end effector that allows the arm to capture stationary or free flying payloads. It provides a large capture envelope and a mechanism capable of soft docking and holding payloads rigid.
For instance, when an International Space Station component, such as a 17-ton Integrated Truss Structure that contains a pair of giant solar arrays, has to be deployed out from inside the shuttle’s cargo bay, the astronaut who operates the Canadarm must first position the robot arm so that the wire noose inside its end effector tightens and pulls the fixture and the large truss structure attached to it snug against the end effector’s rim.

CANADARM End Effectors

CANADARM End Effectors

5) Closed Circuit Television

A closed-circuit television system of cameras and lights on the arm and in the cargo bay transmits pictures to television monitors inside the orbiter to assist the astronauts.

CANADARM Close Circuit Television-3

CANADARM Close Circuit Television-3

CANADARM Close Circuit Television-2

CANADARM Close Circuit Television-2

CANADARM Close Circuit Television

CANADARM Close Circuit Television

6) SRMS Control System.

The Space Shuttle’s general-purpose computer (GPC) controls the movement of the SRMS. The astronaut’s hand controllers tell the computer what the astronauts would like the arm to do.
While the computer is issuing commands to each of the joints, it monitors each joint every 80 milliseconds. Any changes inputted by the astronauts to the initial trajectory commanded are re-examined and recalculated by the GPC and updated commands are then sent out to each of the joints.
When a failure occur, the GPC would automatically apply the brakes to all joints and notify the astronaut of a failure condition.
As with any control system, the GPC can be overridden and the astronaut can operate the joints individually from the flight deck.

7) Thermal Protection System

A white and close-fitting insulated blanket works with thermostatically controlled heaters to keep the Canadarm at acceptable temperatures in the vacuum of space, protecting its components from the intense heat of the sun’s rays, or from extreme cold when the arm is in shadow.

CANADARM thernal protection system

CANADARM thernal protection system

Length 15.2 m (50 ft.)
Diameter 38 cm (15 in.)
Weight on Earth 410 kg (905 lbs.)
Speed of movement – unloaded: 60 cm a second
– loaded: 6 cm a second
Upper and lower arm booms Carbon composite material
Wrist joint Three degrees of movement (pitch/yaw/roll)
Elbow joint One degree of movement (pitch)
Shoulder joint Two degrees of movement (pitch/yaw)
Translational hand controller Right, up, down forward, and backward movement of the arm
Rotational hand controller Controls the pitch, roll, and yaw of the arm

8) End to End Mobility.

This design gives Canadarm the unique ability to walk around the Station on its own, moving end-over-end to the power data grapple fixtures placed around the Station exterior.
The end-over-end concept was born early in the development of Canadarm. Engineers realized that the arm would need extra mobility to reach all parts of the Space Station-more than Canadarm which is attached at one end to the Shuttle.

CANADARM - End to end mobile robotic arm

CANADARM – End to end mobile robotic arm

9) Historic First Move.

When the crew of Mission STS-2 deployed Canadarm for the first time, the moment was marked with feverishness and with incredible expectations. As astronauts Joseph Engle and Richard Truly began to extract the giant robotic arm from Columbia’s cargo bay on November 13, 1981, no image was available at Mission Control.
Canadarm began its long service as the first robotic manipulator system designed specifically for use in the harsh environment of space.
Dr. Garry Lindberg, first program manager for Canadarm.

10) Evolution in Design for CANADA’s Robotic Arm

In December, 1998 Canadarm played a critical role in the first assembly mission of the International Space Station, mating the U.S. Unity Node to the Russian-built Zarya. Canadarm will continue to play a vital role in the assembly of the space station. On STS-100, Canadarm assisted with the delivery and installation of a new generation robotic arm, Canadarm2.
When Canadarm, the Space Station Remote Manipulator System (SSRMS), took the first step off its pallet and onto the International Space Station, it was a dramatic moment that signified an evolution in space robotics.
Unlike the Shuttle’s Canadarm, Canadarm2 is not permanently anchored at one end. Instead, each end-known as a Latching End Effector, or LEE-can be used as an anchor point while the other performs various tasks.

11) CANADARM’s Five years of Success.

Since Canadarm2 was launched five years ago, on Space Shuttle Endeavour, mission STS-100, it has been a vital part of International Space Station construction activities.
During the 2005 Return to Flight mission, an astronaut secured at the tip of the Canadarm2 demonstrated how useful this is. With his feet fixed to Canadarm2, he performed important repair work on the underside of the Space Shuttle so it could safely return to Earth.
Over these five years, Canadian engineers and scientists have been busy taking Canadarm2 to the next level. There’s been a steady stream of upgrades. Ground control of Canadarm2 has been added in preparation for Dextre, the last component of Canada’s contribution to the Space Station.

12) Investment

The Government of Canada invested $108 million in designing, building, and testing the first Canadarm flight hardware, which was given to NASA for the orbiter Columbia. NASA bought four more robotic arms from the industry team, now MDA. The Government of Canada’s original investment resulted in nearly $700 million in export sales. Ongoing maintenance and engineering support add approximately $20 million annually.

13) Conclusion

Canadarm has performed flawlessly for over 30 years; placing satellites into their proper orbit and retrieving malfunctioning ones for repair. Perhaps its most notable mission was the repair of the Hubble Space Telescope. Canadarm was used as a mobile work platform for astronauts during numerous space walks required to repair the faulty telescope. Canadarm played a critical role retrieving the satellite, placing it in the cargo bay for repairs, and then re-deploying it.

Amazon Auto Links: the template could not be found. Try reselecting the template in the unit option page.

by

Speak Your Mind

*