How ROS 2 fastened a robotic arm’s latency, jerky motions

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Optimax Methods is America’s largest optics prototype producer within the medical, protection, and area industries. Optimax optics are aboard Mars rovers, Pluto New Horizons, Tess, ROMAN, Mercury messenger, the ISS, and extra – if it has a lens and goes to area, Optimax most likely manufactured it. In fact, Optimax additionally provides customized lenses right here on Earth for analysis and protection.

Optimax’s R&D workforce approached PickNik for assist in enhancing the smoothness of their robots utilizing the open-source Robotic Working System (ROS) platform of their freeform optics manufacturing course of. A freeform optic is an optic that’s not rotationally symmetric. The manufacturing course of of those optics begins with milling the tough form, then sprucing with an ABB industrial arm and freeform metrology instruments. Ultimate smoothing is then carried out on a Common Robotic or an ABB robotic arm to scale back any errors from earlier steps.

Optimax had points with jerky motions and latency with the ROS 1 ABB arm setup, which had been the first motivators to make use of a new ROS 2 driver. In addition they had a want to maneuver to ROS 2 for higher long-term assist, in addition to for the flexibility to make use of the ROS 2 Management library, a typical low-level controller interface. A driver based mostly on ROS 2 Management additionally permits to be used of PickNik’s admittance controller to take care of fixed pressure throughout sprucing. Nonetheless, no ROS 2 driver for ABB manipulators existed on the time, necessitating the event and launch of abb_ros2, a ROS 2 driver for ABB robotic arms.

Answer

To transition the present ROS 1 structure to ROS 2, PickNik and Optimax collaborated to develop abb_ros2, an open-source driver for ABB arms that makes use of ROS 2 Management. ABB supported this effort by offering entry to their proprietary robotic simulation software program, RobotStudio, which was used to check driver performance throughout growth with no need {hardware}.

Two PickNik engineers labored with Optimax R&D engineers to research Optimax’s information from a ROS 1 prototype. PickNik analyzed the ache factors from the ROS 1 implementation, which centered on latency and jerky movement. Then we developed a plan to handle each of those ache factors, in tandem with the event of a ROS 2 ABB driver.

The driving force communicates instantly with an ABB robotic or simulation, or it may possibly spoof ROS 2 Management drivers for testing with no robotic or proprietary simulation software program. This permits for speedy iteration on planning with out the necessity for customized tooling. The driving force additionally helps coordinating motions with further joints connected to the robotic (exterior axes), such because the bottom-mounted gantry Optimax makes use of to extend their workspace. Lastly, the driving force additionally integrates with the ABB StateMachine add-in], which can be utilized to regulate the robotic through a state machine and IO manipulation.

With the newly-developed ROS 2 Management driver, Optimax had entry to new instruments to resolve their issues. First, enter toolpaths had sharp corners that exceeded the jerk limits of the robotic joints. This will trigger {hardware} points corresponding to faults or long-term injury. Second, the toolpaths Optimax makes use of might have as much as 500,000 waypoints, which precipitated extreme latency when despatched to the robotic. PickNik’s personal MoveIt Ruckig trajectory processing plugin was capable of clean the waypoints such that the ultimate processed trajectory would obey jerk limits, and ship waypoints one after the other to keep away from reminiscence and latency limitations attributable to one big trajectory.

Final result

This collaboration between PickNik and Optimax resulted within the launch of an open-source ROS 2 driver for ABB robots, which the ROS 2 group has extensively used. The driving force was delivered forward of schedule and beneath price range, permitting for growth of further options past the preliminary scope with assist from the open-source group. PickNik’s assist has helped Optimax combine ROS 2 into their manufacturing processes and to leverage the newest trajectory processing options supplied by MoveIt and Ruckig.

This has considerably elevated the general stability of Optimax’s robotic sprucing platform and by way of functionality, has allowed Optimax to extend the dimensions of components that they’ll polish. As well as, PickNik’s collaboration improved Optimax’s information assortment and boosted the gross sales of their pressure controller product.