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Overview

Overview. Objectives Physical Configuration Mechanical Design Power Design Onboard computation Control Software Sensing Testing Resources. Covered so far Still to be covered. Onboard Hardware Selection Issues. Processing horsepower to perform sensor analysis

cameron-norman
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Overview

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Presentation Transcript

  1. Overview • Objectives • Physical Configuration • Mechanical Design • Power Design • Onboard computation • Control • Software • Sensing • Testing • Resources Covered so far Still to be covered

  2. Onboard Hardware Selection Issues • Processing horsepower to perform sensor analysis • Ease of interfacing with motion controllers and sensor feedback • Form factor • Intention is to have it fit in the 4”Ø tubes • Extensibility • Features • i.e. Ethernet, IDE, video • Power consumption • OS support

  3. Controls Issues • Multi-robot planner will have a good but imperfect model of robot positions and environment • In manipulator mode Skyworker becomes a chain manipulator with redundant DOF’s • While walking the payload needs to be moved at a constant velocity to minimize energy consumption and torques • Three types of actions • Walking without payload • Walking with payload • Manipulating from a fixed point

  4. Control Layers

  5. Software Design Issues • Correct errors associated with inexact modeling of world and robot • Modularity • Easy interchange and upgrade of component elements • Objectified components allows melding of simulation and real world • Control partitioning and scalability concerns • Provide the user with a common simulation and operation interface

  6. Software Blueprint

  7. What Will Simulation Provide? • Emulation of Skyworker • An identical interface as used to talk to the real robot • Provides a path for testing prior to implementation on Skyworker • Initially kinematic modeling with a direct path to dynamic modeling • Multi-robot interactions

  8. Purpose of Simulation • Provides a method to explore Skyworker capabilities that we are unable to test with our physical robot • Moving from standing on top of to hanging from the bottom of the truss • Construct a large scale facility • Performing various AIM tasks not demonstrated • Perform and analyze multi-robot operations and their effects on the structure • Study robotic efficiency • Develop tools for optimizing facility construction

  9. Multi-Robot Coordination Robot Coordinator • Executes pre-recorded scripts • Sequences robot actions at high level (I.e. walk to x,y) • Monitors progress Script Generator • Tool used to provide human & machine readable AIM plans • High level actions (move to, carry to, pick up, place, look at) • Initially hand generated (emacs) • Later tools will use the visualization front end • Follow-on research will develop a planning tool

  10. Individual Robot Planning • Translates high level plans into a sequence of steps and then to joint angle trajectories • Provides a route to pass interpreted sensor data to the robot coordinator & user • Separate planners used for walking and manipulating

  11. Joint Control and Sensing • 2 Versions • emulator • code embedded on Skyworker • Local processing of video stream dramatically reduces communications bandwidth • Reflex system used to perform gentle anchoring • Queued joint positions/trajectories provide required low latency control

  12. Simulation/Emulation • Provides feedback to emulated Skyworker • Initial dynamics model will be a unity pass through • Dynamics model will be updated based on characteristics of actual Skyworker

  13. User Interface • Provides a way for users to specify scripts to run, reset the robot and view telemetry data • Visualization tool will allow for full 3D viewing of simulated robots and telemetry data from real robots • Sensor simulation will utilize the visualization infrastructure to provide feedback to simulated Skyworkers

  14. Visualization Software Considerations • Capabilities • Ease of user interaction • Sensor simulation • Leverage available from other RI projects • Cost • Interface

  15. Visualization Packages Being Considered • Viz • Developed at NASA Ames • Currently being used in a multi-robot simulation at FRC • Based on OpenInventor • World Toolkit • Developed by Sense8 • Used on several previous FRC projects • Distribution costs • Envision • Developed by Deneb • Limited FRC experience • Unwieldy to interface to • Extremely expensive to distribute • Enigma • Developed by JSC • Used at NREC

  16. Sensing Requirements • Basic feedback (joint angles, velocities) • Gripper proximity sensing • Payload orientation sensing • Inspection • Localization • Correction of errors in dead-reckoning • Part identification • Used for element tracking and accounting 9 Months Future

  17. Sensing • Proximity Sensing • Purpose • Correct for errors in position estimation • Requirements • Must have multi-centimeter range • Proposed Solution • Capacitive Proximity Sensors (Capaciflectors) • Payload Orientation Sensing • Tasks • Recognize a payload given an estimate of its position • Provide position error feedback as Skyworker manipulator attempts to grasp the payload • Requirements • Recognize payload and latch points given a reasonable amount of error in position and orientation • Provide x,y,z,,, error estimates during capture

  18. Communication Issues • Ease of interfacing on board software with off board software • Ease of access to on board software • Bandwidth considerations • Availability of inter-process communication (IPC) packages over given media

  19. Low Communications Layers

  20. Application Communications Layer

  21. IPC Package Selection Considerations • Ease of Implementation • Support for Peer-to-peer communication (1 to 1) • Support for Publish/Subscribe services (1 to many) • Operating systems supported • Local experience

  22. Feature Comparison • Inter-process communication will likely be performed using IPC • Supports (1 to 1) and (1 to many) messaging capabilities. • Anonymous publish/subscribe will likely by useful • Strong track record with other projects

  23. Testing • Software components will be incrementally tested • Utilize simulation to test algorithms prior to robot completion • Confirm force analyses through real world testing • Validate simulation by comparing simulated operations with real world operations • Determine power consumption for structure walking

  24. Cost Budget

  25. Skyworker Organizational Chart Mobile Robot Design Class

  26. Project Member Responsibilities

  27. Summary • N-Type configuration • System design • Gripper, joints • Force/gait analysis • Gravity compensation • Power • Layered control scheme • 4 tier software architecture • Simulation

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