WEBVTT

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MobileRobot is a research project founded by

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the Federal Ministry of Economic Affairs and Energy, Germany.

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Partnering with GD Engineering & Automation GmbH

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and Götting KG, the goal is to break

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the boundaries of mobile manipulation.

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So MobileRobot is a mobile manipulator,

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a robotic workhorse that combines

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the handling abilities of a robot arm

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with the flexibility of a mobile platform.

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On top we have a standard KUKA six-axis industrial

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robot arm equipped with a welding torch as a tool.

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But since we don't weld here for

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safety reasons, a red light indicates

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where the welding process takes place.

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The mobile platform consists of

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two drive steering modules that can make

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the platform go in any direction needed.

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For navigation purposes, we have a 270 degrees

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laser rangefinder on the platform

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that works in conjunction with this

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2D line laser that is installed at the tool,

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so the surrounding area can be mapped and

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the workpiece can be identified.

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Every welding task starts with the teach-in process,

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where certain key points of

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the welding trajectory are recorded.

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The teach-in process is conducted by the

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KUKA control pad, using a custom app that

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not only controls the manipulator,

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but also the platform in a unified way.

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First the base is positioned close to the work area.

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Using the manipulator, the tool tip is set

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on the key point to be recorded.

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The point is stored on the control system,

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which includes information about

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the coordinates of the platform,

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the joint angles of the manipulator, as well as

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the sensors information of the 2D line laser.

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In this way, every keypoint is located in

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the work area's reference frame.

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This process is repeated for all keypoints

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along the welding path, creating

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a path consisting of connected lines.

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The keypoints are used as input for the

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path planner, to create a trajectory that

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moves the platform and the manipulator

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along the needed welding track.

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Using the 2D line laser, a closed-loop controller

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can follow the welding trajectory.

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The stored keypoints are located in 3D

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using the platform's position, the joint angles,

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and the data of the 2D line laser.

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Using the stored keypoints,

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MobileRobot's path planner plans

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a path connecting all keypoints.

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By guiding the tool along this trajectory,

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the exact welding path is followed using

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the trajectory controller.

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Starting from a parking position,

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MobileRobot first approaches the workpiece.

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Relying on the platform's 270 degrees LiDAR sensor,

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the start point of the welding trajectory

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can be approached autonomously.

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The manipulator's joints approach

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the orientations, recorded for the first

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keypoint during teach-in.

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With this, the workpiece enters

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the 2D line laser's sensor area,

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which engages a second localization layer

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centered around the tool.

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Relaying on a trajectory created by the

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path planner, the welding operation starts

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once the start pose is reached.

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Curvatures or obstacles along the path are

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detected by the tool's 2D line laser

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and the closed-loop trajectory control

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keeps the tool on track.

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Once the welding operation is fully executed,

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MobileRobot autonomously clears

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the work area by reaching

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for the set parking position.