Robotics and Although shuttle astronauts made their work in space look like an everyday event, it was in fact a hazardous operation. Using robotics Automation or human-assisted robotics and automation eliminated the risk to the crew while still performing the tasks needed to meet the mission Introduction objectives. The Shuttle Robotic Arm, commonly referred to as Gail Chapline “the arm ,” was designed for functions that were better performed Steven Sullivan by a robotic system in space. Shuttle Robotic Arm Henry Kaupp Automation also played an important role in ground processing, Elizabeth Bains inspection and checkout, cost reduction, and hazardous operations. Rose Flores For each launch, an enormous amount of data from verification Glenn Jorgensen Y.M. Kuo testing, monitoring, and command procedures were compiled and Harold White processed, often simultaneously. These procedures could not be done Automation: The Space Shuttle manually, so ground automation systems were used to achieve Launch Processing System accurate and precise results. Automated real-time communication Timothy McKelvey systems between the pad and the vehicle also played a critical role Integrated Network Control System Wayne McClellan during launch attempts. In addition, to protect employees, automated Robert Brown systems were used to load hazardous commodities, such as fuel, Orbiter Window Inspection during tanking procedures. Throughout the Space Shuttle Program, Bradley Burns NASA led the development and use of the most impressive innovations Robotics System Sprayed Thermal in robotics and automation. Protection on Solid Rocket Booster Terry Huss Jack Scarpa 286 Engineering Innovations Shuttle Robotic Arm — In December 1969, Dr. Thomas Paine, environment. From a technical then administrator of NASA, visited perspective, it combined teleoperator Now That You Canada and extended an offer for technology and composite material Have the “TRUCK,” Canadian participation with a focus technology to produce a lightweight on the Space Shuttle. This was a result system useable for space applications. How Do You Make of interest by NASA and the US In fact, the arm could not support its the Delivery? government in foreign participation own weight on Earth. The need for a in post-Apollo human space programs. means of grappling the payload for In 1972, the Canadian government deployment and retrieval became Early in the development of the indicated interest in developing the apparent. This led to an end effector— Space Shuttle, it became clear that Shuttle Robotic Arm. In 1975, Canada a unique electromechanical device NASA needed a method of deploying entered into an agreement with the made to capture payloads. and retrieving cargo from the shuttle US government in which Canada payload bay. Preliminary studies Unique development and challenges of would build the robotic arm that would indicated the need for some type of hardware, software, and extensive be operated by NASA. robotic arm to provide both modeling and analysis went into the capabilities. This prompted the The Shuttle Robotic Arm was a Shuttle Robotic Arm’s use as a tool for inclusion of a Shuttle Robotic Arm three-joint, six-degrees-of-freedom, delivery and return of payloads to and that could handle payloads of up to two-segment manipulator arm to be from orbit. Its role continued in the 29,478 kg (65,000 pounds). operated only in the microgravity deployment and repair of the Hubble Backdropped by the blackness of space and Earth’s horizon, Atlantis’ Orbiter Docking System (foreground) and the Canadarm—the Shuttle Robotic Arm developed by Canada—in the payload bay are featured in this image photographed by an STS-122 (2008) crew member during Flight Day 2 activities. Engineering Innovations 287 Space Telescope, its use in the building arm. The main robotic arm processor— current limit commands that were sent of the space station and, finally, in also part of the cabin electronics— to the arm-based electronics. Return to Flight as an inspection and handled all data transfer among the arm, The arm was thermally protected with repair tool for the Orbiter Thermal the displays and controls panel, and the specially designed blankets to reduce Protection System. main shuttle computer. The main shuttle the susceptibility of the hardware computer processed commands from the to thermal extremes experienced operator via the displays and controls during spaceflight and had an active Evolution of the Shuttle panel; received arm data to determine thermostatically controlled and Robotic Arm real-time position, orientation, and redundant heater system. The initial job of the Shuttle Robotic velocity; and then generated rate and Arm was to deploy and retrieve payloads to and from space. To accomplish this mission, the system Shuttle Robotic Arm System that was developed consisted of an anthropomorphic manipulator arm Window located in the shuttle cargo bay, cabin Bulkhead View Closed-cirCClosed-circuitlosed-circuit TTelevisionelevision Monitors equipment to provide an interface to Closed-circuitClosed-circuit the main shuttle computer, and a human TelevisionTelevision interface to allow an astronaut to Shuttle control arm operations remotely. Robotic Arm The manipulator arm consisted of three joints, two arm booms, an end Cabin Electronics effector, a Thermal Protection System, and a closed-circuit television system. Arm joints included a shoulder joint Hand with two degrees of freedom (yaw and Controller pitch), an elbow joint with one degree of freedom (pitch), and a wrist joint with three degrees of freedom (pitch, Displays and Hand CControlsontrols Panel CControllerontroller yaw, and roll). Each joint degree of freedom consisted of a motor module driving a gear box to effect joint WristWristrist Closed-circuitClosed-circuit TelevisionTelevision StandardStandard movement and appropriate local and Lights End EffectorEffectorf processing to interpret drive commands Thermal ElbowElbow Closed-circuitClosed-circuit Payload PProtectionrotection Kit originating from the cabin electronics. TelevisionTelevision on Pan and The cabin electronics consisted of a Tilt Unit displays and controls subsystem that CClosed-circuitlosed-circuit TTelevisionselevisions provided the human-machine interface to allow a crew member to command the arm and display appropriate information, including arm position Retention and velocity, end effector status, Devices temperature, and caution and warning information. Additionally, in the A crew member could manually control the arm from inside the crew compartment using a translational hand controller and a rotational hand controller. The crew received displays and controls subsystem, two feedback visually via the displays and controls panel and the closed-circuit television hand controllers allowed man-in- monitors, and directly through the shuttle crew compartment windows. The crew could the-loop control of the end point of the also control the arm in automatic mode. 288 Engineering Innovations Components of the Shuttle Robotic Arm Crew Compartment Translational Display and Hand Controller Control Panel Thermal Joint Brakes Blankets End Effector Arm Electronics Data From/To Shuttle Arm Booms General Purpose Computer Rotational End Effector Hand Electronics Unit Controller Joint Gearbox End Effector Brakes and Clutches Manipulator Arm Electronics Controller Interface Unit Joint Motor With a total length of 15.24 m (50 ft), the Shuttle Robotic Arm consisted of two lightweight high-strength tubes, each 0.381 m (1.25 ft) in diameter and 6.71 m (22 ft) in length, with an elbow joint between them. From a shoulder joint at the base of the arm providing yaw and pitch movement, the upper boom extended outward to the elbow joint providing pitch movement from which the lower arm boom stretched to a wrist joint providing pitch, yaw, and roll movement. The end effector was used to grapple the payload. The closed-circuit television system The interfacing end of the Shuttle Close-up View of End Effector consisted of a color camera on a pan/tilt Robotic Arm was equipped with a and Grapple Fixture unit near the elbow joint and a second fairly complicated electromechanical camera in a fixed location on the wrist construction referred to as the end joint, which was primarily used to view effector. This device, the analog a grapple fixture target when the arm to a human hand, was used to grab, was capturing a payload. or grapple, a payload by means of a tailored interface known as a Self checks existed throughout all the grapple fixture. End Effector Shuttle Robotic Arm electronics to assess arm performance and apply The end effector was equipped with a appropriate commands to stop the arm, camera and light used to view the should a failure occur. Caution and grapple fixture target on the payload warning displays provided the operator being captured. The robotic arm with insight into the cause of the failure provided video to the crew at the aft Grapple Fixture and remaining capability to facilitate flight deck, and the camera view helped the development of a workaround plan. the crew properly position the end Engineering Innovations 289 . d e v r e s d e n r a s r t e h l i g i w r t l t l e A D . , d t d l L a s n e o t D a i c c a o s M s A © End Effector Capture/Rigidize Sequence: The left frame illustrates the snares in the open configuration, and the second frame shows the snares closed around the grapple shaft and under the grapple cam at the tip of the grapple shaft. The next frame illustrates the snares pulling the grapple shaft inside the end effector so the three lobes are nested into the mating slots in the end effector, and the final frame shows the snare cables being pulled taut to ensure a snug interface that could transfer all of the loads. d e v r e s e r s t h g i r l l A . d t L s e t a i c o s s A d n a r e l i w t t e D , d l a n o D c a M © Flat floor testing of the Shuttle Robotic Arm.