Autonomous pallet transportation in factory floor environments
Multi-pallet detection in factory floor environments
Within the HR-Recycler a novel pallet-truck AGV for the autonomous transportation of the pallets between classification and the workstations will be developed to enable automation in intra-factory logistics transportations of WEEE devices within a collaborative factory floor environment. The pallet-truck to be developed should be endowed with multi-pallet detection and pallet pick up navigation and control capabilities.
Technical Challenges
Pallet-truck AGVs’ operation in human populated factory environments is a challenging task, especially when there is a demand to operate without following fixed paths defined by guide wires, magnetic tape, magnets, or transponders embedded in the floor. There are several methods that tackle the task of autonomous pallet transportation and they are usually relied on computer vision approaches varying for indoor/outdoor environments. Yet, most of them are devoted to operate in predetermined paths and their global navigation is controlled by a central system typically linked to the Enterprise Resources Planning (ERP) of the factory.
Robotic Solution: Multi-pallet detection and docking strategy
A dedicated method has been developed by CERTH-ITI for the pallet-truck AGV developed by Robotnik partner within the HR-Recycler project. The solution comprises a vision-based method that enables safe and autonomous operation of pallet moving vehicles that accommodate pallet detection, pose estimation, docking control and pallet pick up in such industrial environments. A dedicated perception topology has been applied relying on stereo vision and laser-based measurements installed on-board a nominal pallet truck model. Pallet detection and pose estimation is performed with model-based geometrical pattern matching on point cloud data, exploiting CAD models of universal types of pallets, while robot alignment to candidate pallet is performed with a dedicated visual servoing controller. To allow safe and unconstrained operation, a human-aware navigation method has been developed to cope with human presence both during global path planing and during pallet-docking navigation phase. The developed method has been assessed in Gazebo simulation environment with a pallet truck model and proved to have real-time performance achieving increased accuracy in navigation, pallet detection and pick-up (see Figure1)
The Visual Analytics Lab (VARLab) of CERTH-ITI
Figure 1 In first figure, the robot approaches the pallet form-up area in Gazebo simulation environment. In the second figure the multi-pallet detection algorithm is applied along with the global planner algorithm that navigates the robot towards the alignment state. A point-to-point visual servoing controller drives the pallet-truck towards the selected pallet, as illustrated in third figure. The last figure outlines the docking and final pick-up of the pallet with a joint state controller.
