Robotic motion planning for 8- DOF motion stage

Robotic motion planning for 8- DOF motion stage 12 November Mark Geelen Simon Jansen Alten Mechatronics www.alten.nl rosindustrial@alten.nl

Introduction Introduction Alten FEI Motion planning MoveIt! Proof of principle study Results 2

Alten ALTEN THE TECHNOLOGY PARTNER Alten Alten PTS Mechatronics Technical & Software Robotics Embedded Controls Software Simulation Mechanics & Modeling Monitoring & Control Electronics 250 40 Employees Employees 3

Alten Contract Development in Technology At the customer site: Consulting & Engineering Inhouse: Projects and R&D Outsourcing Knowledge development Training 4

FEI World leader in Transmission microscopy Scanning electron optics microscopy Ion beam microscopy Worldwide 2700+ employees 5

Problem description Small Dual Beam systems Vacuum chamber is very crowded Electron column Ion column Stage with 8 DOF s Detectors and gas injection systems SDB systems not only microscopes, but more small nano fabrics Used to remove or add material, e.g. circuits on wafers Possible to perform chemical analysis of samples 6

Problem description Problem: Finding a collision free path for the 8DOF s stage through the crowded microscope chamber, without colliding with other objects Current implementation: Calculates the axis of movement separately No collision checking Axis are then moved sequentially Drawbacks: Calculation and movements are taking to much time No collision checking, moves are safe because they are in the calculated path, only applicable in the exact same scenario 7

Apply robotic solutions to problem Idea: Can we use tools from the world of robotics and apply them to this high-tech system problem? Surprising number of parallels! Robot arm Motion stage High number of DOF s Collision checking Complex moves Motion stage can be considered as a robotic arm! 8

ROS What is it? Robot Operating System - ROS Framework of state of the art software and tools for creating robotic applications Set of software libraries Robot geometry libraries - TF Standard robot messages e.g. geometric concepts; pose, transforms and vectors for sensors Motion planning for mobile applications and robot arms Tooling Physics simulator Visualization 9

Moveit! Software library embedded in ROS Mobile manipulation Incorporating the latest developments in motion planning, manipulation, 3D perception, kinematics, control and navigation Platform for developing advanced robotics applications Open-source Has been used on over 65 robots! 10

Motion planning MoveIt! How to get from all your input to a controlled robot, e.g. arm Define the behavior of the arm given certain conditions? Source: http://aeswiki.datasys.swri.edu/rositraining/ 11

Traditional robot programming Motion types Limited but well-defined, one motion task Environmental model None Execution monitor Application specific Source: http://aeswiki.datasys.swri.edu/rositraining/ 12

ROS motion planning MoveIt! Motion types Flexible, goal driven, with constraints Environmental model Automatic, based on live sensor feedback Execution monitor Detects changes during motion Source: http://aeswiki.datasys.swri.edu/rositraining/ 13

FEI and motion planning Proof of principle study performed Prove in a simulated environment, that the ROS tooling is capable of solving complex motion planning problems Incorporating collision checks Show the benefits of using the ROS tool MoveIt! 14

Simulation model Real system Simulation model 15

Modeling (1) Very flexible implementation: Planning algorithm independent from the simulation model Adding modules No code compilation Parameterized model, calibrations can be included Convert file format ROS visual model CAD model Simulation model Convert file format Simplify model Add airbag ROS collision model 16

Modeling (2) Visual model r_stem Schematic top view 17

Modeling (3) Collision model with airbag to include tolerances and uncertainties Schematic top view 18

Problem description Problem description Motion planning for an 8 DOF stage Finding a collision-free movement (trajectory) between two given configurations Start configuration End configuration 19

Motion stage Planning groups 20

Planner Path generation based on start and end configuration of stage Start configuration Success Path generation Collision check End configuration Fail 21

Use cases Motion planner tested on three use cases 1 benchmark case 2 cases that are currently impossible ( stress tests ) Case Current MoveIt! Benchmark Stress test 1 Stress test 2 In the benchmark case, MoveIt! performed up to 5 times faster than current solution!

Simulation results - stress test 2 Calculated trajectories/paths per axis 23

Simulation results - stress test 2 24

Conclusion Implemented motion planning using ROS successfully Motion plans up to 5 times faster than current solution Requires no additional programming when adding modules Is able to check for collisions Is generic for all cases and does not need fine-tuning Generates non-trivial collision free paths for all use cases 25

Thank you for your attention! 26

Robotic motion planning for 8- DOF motion stage 12 November 2014 Mark Geelen Simon Jansen Alten Mechatronics www.alten.nl rosindustrial@alten.nl