Crane load positioning and sway monitoring using an inertial measurement unit

Crane operation is one of the most essential activities on construction sites. However, operating a crane is a sophisticated job which requires the operator to have extensive skills and experience, and most importantly a comprehensive understanding of crane motions. Besides typical crane motions such as boom slew, hoist, and extension, monitoring and controlling the position of the load is extremely important to avoid struck-by accidents caused by crane load, especially when the load swings as a result of wind and inertia. Although typical motions can be captured by some existing techniques, a reliable approach to position the load and monitor the load sway remains missing. This study proposes an orientation-based approach for tracking crane load position and monitoring load sway in daily lifting activities. This approach adopts an off-the-shelf inertial measurement unit (IMU) module for measuring load orientation, and an efficient algorithm for converting orientation measurements to load positions. The proposed approach was tested in two load sway scenarios in a controlled lab environment. Test results indicate that the proposed approach correctly converted orientation measurements to accurate load positions and reconstructed the load sway trajectory in both linear and circular sway motions. Enabling continuously monitoring of crane load motion, this approach augments the crane motion information obtained by typical crane motion capturing systems. The findings in the research will advance the safety practices in crane lifting activities.