Deployable Grapple Fixture for AERCamDGF ProjectDGF ProjectJason ArnoldIDEAAS and DGF TeamJohnson Space Center Automation Robotics and Simulation DivisionUniversity of Colorado Structural Dynamics and Control Laboratoryhttp://aerospace.colorado.edu/IDEAASJSCCharles PriceChristopher CulbertSDCLDr. Lee PetersonJason HinkleProject Overview• NASA Proposal for a Robotic Arm to be placed on AERCam•The purpose of the arm is to provide station keeping ability and EVA assistance to astronauts•IDEAAS Senior Design Project•Summer Grant Proposal for further work•Final Report submitted to JSC before the end of Fall ’99Deployable Grapple Fixture for AERCamAERCam Overview• To be used for EVA observation, assistance, or damage assessment• 13 inch diameter• 33 pounds• 12 Nitrogen thrusters• Controlled from within the Shuttle• Manual & automatic attitude control• Video link to the Shuttle via S band• Non-rechargeable batteries and Nitrogen tankDeployable Grapple Fixture for AERCamRequirements for the Appendage• DGF will extend to 3 ft beyond the AERCam surface• The total mass cannot exceed 3 pounds• Maximum power draw = 15 W during actuation, 2 W during quiescence• DGF must stow within the surface of AERCam• The stowed volume cannot exceed 72 cubic inches• DGF must grasp an EVA handle and a 1/4-inch tether• DGF must be able to null a lateral disturbance or closure rate of 0.02 ft/sec• DGF must have at least 6 DOFDeployable Grapple Fixture for AERCamIDEAAS Bellows versionDeployable Grapple Fixture for AERCam•Cable Joints• use bellows as joints• cables used to actuate appendage, 2 stages will be required• gripper wires run through interior of arm• FEM performed to verify joint will bend as expected•Arm stowed on the outside of AERCam in a grooveDeployable Grapple Fixture for AERCamGripper Design•Claw Design•Fully open it can accommodate a standard EVA handle•When closed it can grip a standard ¼” tether•Will have padding similar to EVA suit to protect the astronauts and ISS•Actuated by a Smoovy motor in the gripper arm interface or “wrist”Deployable Grapple Fixture for AERCamGripper/DGF Interface• 1 Smoovy bi-directional 8mm rotary motor will perform two tasks:– Gripper rotation (360º)– Claw actuation• 1 Smoovy linear motor that will move the rotary motor between each task.• Each motor will be controlled by a Smoovy open-loop controller.• Gear lock between the gripper and gripper/DGF I/F box to prevent rotation during claw actuation.Deployable Grapple Fixture for AERCamGripper/DGF Interface Positions• Gripper Rotation:• Internal gear mounted on gripper base plate • Gripper-Claw Actuation:• Gear system on gripper clawsDeployable Grapple Fixture for AERCamGrippable Surface• IDEAAS bellows design grippable surface:•The following pictures show different views of the surface that can be covered by the modified IDEAAS concept Deployable Grapple Fixture for AERCamProject Continuation• This project will be taken under advisement at JSC for possible completion and implementation•AERCam 2 currently being designed at JSC•Possible implementation of more dexterous arm for future work •Tool manipulation•Repair work?Deployable Grapple Fixture for AERCamQuestions?Deployable Grapple Fixture for
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