Automation of a tow-tractor for the autonomous delivery of materials in an industrial complex

Autonomous Guided Vehicles (AGVs) have been broadly used in industrial environments allowing companies to save money, be more efficient and get a robust system for the movement of materials and goods. AGVs are designed to follow a route autonomously by using different types of sensors to avoid collisions and track their position. Nowadays, it is possible to find in the market different configurations for this kind of vehicles such as tuggers, lift trucks and flat platforms for heavy or regular loads. Nevertheless, when an AGV is introduced in an existing productive process some inconveniences could arise. One of the main problems is that the facility must be modified in order to incorporate landmarks such as magnetic floor lines or reflecting laser spots. The old transportation system must be replaced, and the new equipment cannot be used out-off the area predefined for their transit. To solve the aforementioned problems, a system that enables a conventional industrial tractor to generate and follow a route autonomously has been designed. Sensors and actuators have been added to the tractor systems allowing control of brake, steering, acceleration, transmission, parking brake and all the electrical functions. A two-level control system has been implemented. At the lower layer, a PLC controls the basic functions to move the tractor and implements the first level of security to avoid collisions. At the upper layer, a computer running robot operating system uses the camera, LiDAR and encoders to complete the navigation task. The results show that the proposed system could be considered for autonomous transportation of materials within an industrial complex. This approach does not require modifications in the facilities and can be adjusted to fit in different tractor models avoiding the replacement of the existing equipment. The design allows the tractor to be driven by an operator in a regular way, allowing their use out-off the autonomous route and for different purposes.