Autonomous Robotic Capture to Validate Ground-Based Contact Dynamics Simulation

PI: Brian Roberts, Satellite Servicing Capabilities Office (SSCO), NASA/Goddard Space Flight Center

NASA’s Goddard Space Flight Center (GSFC), in partnership with West Virginia University and Yaskawa America, Inc., is conducting robotic contact dynamics evaluations in a near-zero gravity environment on an airplane. Knowledge gained during these flights is being used to mature autonomous capture algorithms and to enhance the accuracy of a simulation platform at NASA’s Goddard Space Flight Center. This platform is used to support the development and validation of technologies required for the autonomous capture and servicing of satellites in geosynchronous and low Earth orbit, and potentially the capture/disposal of large orbital debris, among other missions. These technologies could also support the Near Earth Asteroid Robotic Precursor mission and the Near Earth Asteroid Human mission. The experiment will help answer some of the technical challenges identified in NASA’s Office of the Chief Technologist’s Robotics, Tele-Robotics, and Autonomous Systems Roadmap.

Technology Areas (?)
  • TA04 Robotics, Tele-Robotics and Autonomous Systems
Problem Statement

One of the greatest challenges in developing a realistic simulation platform is accurately simulating the dynamic response of a free-floating object. Current ground simulations of on-orbit autonomous robotic capture and servicing do not adequately model the small-scale 3-D contact dynamics between a robot and a satellite. Data collected during the flights is helping to better characterize the current models used in the Goddard Satellite Servicing Center facility at NASA’s Goddard Space Flight Center.

Technology Maturation

Data collected during the flight campaigns is helping to mature autonomous capture algorithms for a wide range of missions and is also helping to quantify a ground-based dynamics simulation platform at NASA’s Goddard Space Flight Center. Prior to the flights, the autonomous capture technology was at a technology readiness level (TRL)-3. Testing autonomous capture in a relevant environment (i.e., near-zero gravity) raised the TRL to 4 after the flight. The flights also advanced the TRL of the ground-based contact dynamics simulation platform by providing “truth” data about the behavior of a free-floating object being touched by a robotic manipulator.

Future Customers

Through this experiment, Goddard’s Satellite Servicing Capabilities Office is advancing technologies and capabilities relevant to several NASA Centers and applicable to critical missions. The autonomous capture algorithms being tested are applicable to any mission involving the capture of non-cooperative clients in space and could also be used for sample return. These capabilities are especially relevant to satellite servicing and debris removal missions. NASA could use the Goddard contact dynamics simulation platform to replicate the proximity operations of a spacecraft around an asteroid and to simulate subsequent contact operations, such as attaching to the asteroid, drilling into the surface, etc. Additionally, NASA is investigating ways to make these capabilities available to the fledgling commercial satellite-servicing industry.

Flight Experiment Objectives

A robotic system with a sensor suite was placed inside a cage on the airplane and commanded to autonomously track and “touch” a free-floating object. The experiment tested the ability of the sensors to extract the key features of the target and calculate their relative position and orientation. It also measured the rate and force with which the robot contacted the object and measured the response of the free-floating target.

Payload Description

The robot and cage were fixed to the aircraft. During each zero-g segment, a massive object was released so that it was free-floating within the cage. The robot used its onboard sensor suite to attempt to track the free-floating object. The robot also contacted the object and a metrology system measured the motion of the robot and object. This data is being used to program robots in Goddard’s Satellite Servicing Center facility to move the same way the robot and the object did on the airplane. The response of the Goddard robot simulating the free-floating object will be compared with the data collected during the flight. The flight data will then be used to “tune” and validate the ground-based contact dynamic simulation.

Technology Details

  • Selection Date
    AFO1 (May 2011)
  • Program Status
  • Current TRL (?)
    TRL 4
    Successful FOP Campaigns
  • 2 Parabolic

Development Team

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