Safety Control of Automatic Excavator for Swing Collision Avoidance

The importance of safety for automated construction machinery is continuously increasing. Especially, excavators are frequently exposed to fatal accident because it works closely with human workers. Distance - based safety technique lacks the analysis of the braking ability of the excavator's hydraulic system and the dynamic motion of the object. In this study, we propose a collision avoidance safety algorithm to secure a consistent and reliable safe distance. By calculating relative velocity and rotational inertia in real-time, the proposed controller determines the exact braking time of swing motion. For this purpose, the object motion was tracked using a laser scanner sensor and the rotational inertia was calculated by inclinometer posture sensor. We carried out the experiment on the actual vehicle to evaluate the safety margin when stop control completed. The result shows a reliable performance of safety distance which satisfied desired margin with ± 0.25m error. It is expected that the proposed safety control technology can be extended to other equipment in various construction site.