The Next Step SPACE ROBOTICS INITIATIVE Skyworker PDR 9/10/99-24 Objectives Physical Configuration Mechanical Design Power Design Onboard computation Control.

The Next StepSPACE ROBOTICS INITIATIVE

Skyworker PDR 9/10/99-1

• Objectives

• Physical Configuration

• Mechanical Design

• Power Design

• Onboard computation

• Control

• Software

• Sensing

• Testing

• Resources

Covered so farStill to be covered

OverviewOverviewOverviewOverview



Onboard Hardware Selection IssuesOnboard Hardware Selection IssuesOnboard Hardware Selection IssuesOnboard 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



Controls IssuesControls IssuesControls IssuesControls 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



Control LayersControl LayersControl LayersControl Layers



Software Design IssuesSoftware Design IssuesSoftware Design IssuesSoftware 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



Software BlueprintSoftware BlueprintSoftware BlueprintSoftware Blueprint



What Will Simulation Provide?What Will Simulation Provide?What Will Simulation Provide?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



Purpose of SimulationPurpose of SimulationPurpose of SimulationPurpose 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



Multi-Robot CoordinationMulti-Robot CoordinationMulti-Robot CoordinationMulti-Robot CoordinationRobot 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



Individual Robot PlanningIndividual Robot PlanningIndividual Robot PlanningIndividual 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



Joint Control and SensingJoint Control and SensingJoint Control and SensingJoint 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



Simulation/EmulationSimulation/EmulationSimulation/EmulationSimulation/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



User InterfaceUser InterfaceUser InterfaceUser 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



Visualization Software ConsiderationsVisualization Software ConsiderationsVisualization Software ConsiderationsVisualization Software Considerations

• Capabilities– Ease of user interaction– Sensor simulation

• Leverage available from other RI projects

• Cost

• Interface



Visualization Packages Being Visualization Packages Being ConsideredConsidered

Visualization Packages Being Visualization Packages Being ConsideredConsidered

• 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



Sensing RequirementsSensing RequirementsSensing RequirementsSensing 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



SensingSensingSensingSensing• 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



Communication IssuesCommunication IssuesCommunication IssuesCommunication 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



Low Communications LayersLow Communications LayersLow Communications LayersLow Communications Layers



Application Communications LayerApplication Communications LayerApplication Communications LayerApplication Communications Layer



IPC Package Selection ConsiderationsIPC Package Selection ConsiderationsIPC Package Selection ConsiderationsIPC 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



Feature ComparisonFeature ComparisonFeature ComparisonFeature ComparisonIPC Package

1-1 1-Many Local Experience

Platforms

IPC Yes Anonymous Yes SunOS, Solaris, VxWorks, Linux, IRIX

RTC Yes Named Yes Solaris, Linux, Irix, VxWorks, Windows NT, DOS4GW

Socket++ Yes No No Solaris, AIX, Linux, Windows 95/NT

• 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



TestingTestingTestingTesting

• 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



Cost BudgetCost BudgetCost BudgetCost Budget

Mechanical 48500DOF 11 @ 3000 33000Grippers 3 @ 4000 12000Structure 1000GC 1000Testing Equipment / Facility 1500

Computational 7300Embedded Computer 1500Wireless 2000Motor Controllers 2500Video capture 600Digital IO 700

Sensors 2750Camera 750Joint Sensing, Capaciflectors, Force Sensors1500RF Tag Sensor 500

Power 3500Batteries 1500Power Circuitry 2000

Total 62050



Skyworker Organizational ChartSkyworker Organizational ChartSkyworker Organizational ChartSkyworker Organizational Chart

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Mobile Robot Design Class



Project Member ResponsibilitiesProject Member ResponsibilitiesProject Member ResponsibilitiesProject Member ResponsibilitiesTeam Member ResponsibilitiesWilliam ”Red” Whittaker Principal Investigator, technical oversight

Peter Statitz Mechanical lead, mechanical design and analysis, manufacturing

Chris Urmson Electrical and Software lead, software architecture design

Dimi Apostolopoulos Mechanical design, Mechanical oversight

Sanjiv Singh Software oversight

Jim “Oz” Osborn Project management

Ben Shamah Mechanical design, manufacturing

Sarjoun Skaff Mechanical analysis, manufacturing

William Wong Simulation development

DeWitt Lattimer Sensor interfacing and integration

Scott Robins Embedded software development

Jason Messinger Embedded processor integration and hardware interfaces

Oren Laskin Visualization

Jonathan Samuel Power system design, motor controller selection/design

Tim Warneck Power system design, motor controller selection/design

Marion “Trey” Smith Simulation development



SummarySummarySummarySummary

• N-Type configuration

• System design– Gripper, joints– Force/gait analysis– Gravity compensation – Power– Layered control scheme– 4 tier software architecture

• Simulation

The Next Step SPACE ROBOTICS INITIATIVE Skyworker PDR 9/10/99-24 Objectives Physical Configuration Mechanical Design Power Design Onboard computation Control.

Documents

skyworker capabilities

emulation of skyworker

real robot

physical robot

manipulator mode skyworker

overviewoverview slide

multirobot operations

individual robot planning