**1. Introduction**

Robots have been used in applications such as industry, medicine, agriculture, space, education, underwater exploration and many others. Manufacturing processes in industries have

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

increased considerably the use of robotic arms to automate repetitive and tedious tasks performed under difficult conditions for workers. Moreover, the use of mobile robots in industries also improves the efficiency and accelerates the production process. Mobile robots are equipped with sensors to analyze and interpret information about the environment during navigation [1]. Some applications of mobile robots in industry are as follows:

This chapter describes, in Section 2, the global strategy used to design, implement and program the palletizer robot. The robot implementation and the A-start algorithm are explained in Section 3. Experimental results are presented in Section 4. Finally, Section 5 includes the

Design and Implementation of a Demonstrative Palletizer Robot with Navigation…

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The palletizer robot proposed here moves a box from place A to place B while navigating and avoiding collisions. To attain this goal, the main tasks involved and tackled here are as

In general, the strategy programmed and performed by the palletizer robot is described in the block diagram of **Figure 1**. Both programming strategies DaNI and NXT are combined, but the control of the overall task is programmed on the mobile robot DaNI. The action "*compute trajectory to the box*" in the diagram uses the A-star algorithm and receives a predefined map of the environment with all static obstacles on it. This action is programmed on the DaNI robot, and it is performed in two stages; first, the robot moves to the box position and, second, the robot moves to the final pallet. Once the robot performs the first stage and arrives to the box position, the action "*set gripper ready*" involves the configuration and positioning of the gripper to take the box. This action was programmed on the NXT Lego. Once sensors indicate that the gripper has taken the box, the second stage of the trajectory is performed and the robot moves to the "*go to final pallet*" action. The robot locates the gripper and leaves the box carefully on the pallet. Then, the robot goes back to the initial position and the same process starts again if more boxes must be moved. Finally, dynamic obstacles are detected using the sonar sensor during robot mobile navigation and the robot stops if an obstacle is found in its path, and it continues its trajectory when the obstacle is not detected

The mobile robot used in this project is the robotic platform called NI LabVIEW robotics Starter Kit®, described in [8], also known as DaNI 2.0, developed by NI. This mobile robot was designed to develop and run algorithms in real time for autonomous system applications

Each wheel of the robot is connected to a DC motor which provides the traction force and stabilization wheel for balancing the robot; the kinematic model and the representation of robot position used in this work is the same as the one presented in [5]. The sbRIO-9632 card

and can be programmed on two different languages: LabView or C.

**3.** Performing the robot trajectory and robot interacting with the dynamic obstacles

conclusion and outlines future work.

follows:

anymore.

**2.1. Robot model description**

**2. Global strategy for palletizer robot navigation**

**2.** Path planning strategy based on an A-star algorithm

**1.** Perception of the environment by using sonar and contact sensors


The palletizing of objects (essentially boxes) in the industry is the process to accommodate boxes on a pallet that is usually performed by fixed robotic arms [3, 4]. In cases when the destination is not fixed, mobile robots are also used to place boxes to a destination. For instance, magnetic strip-guided robots transport the merchandise successfully, albeit only following a linear path. Therefore, one of the best solutions for palletizing objects from an origin to a destination involves the use of robotic arms mounted on mobile robots.

The palletizing task requires a path planning strategy which consists in finding an obstacle-free path for mobile robot navigation from one place to another. Many path planning strategies can be found in the literature for various applications, ranging from video game programming to outdoor autonomous navigation of robots. Path planning methods are based on simplifying the searching area to a 2D matrix in which each element represents a reduced square area of the navigation area (that will be interpreted as a cell) [5]. Thus, each cell can be navigable or not depending on the obstacles on it, and a resulting path is obtained if a set of adjacent navigable cells from the origin to destination is found.

The aim of implementing a Box Palletizing Robot is to encourage young people to explore robotic issues as modular tasks that require design, mathematical modeling, programming and some interest and creativity. In this context, many robotic kits and prototypes have been introduced by different companies such as Vex [6], Arduino, Lego, Zowi from BQ [7], to name but a few. However, in this chapter, we present a palletizer robot that combines two robotic kits: the mobile robot platform Dani from National Instruments (NI) and the Lego Mindstorms NXT 2.0 8547 model used to build the robotic arm. Both robotic kits require basic, medium and high levels of knowledge in line with the final purposes. In our case, we will describe the design, programming and synchronization of both kits.

Additionally, the path planning strategy used in this project is based on the A-star algorithm and basic strategies to control the robotic arm. The characterization of the robotic arm is based on a parallel structure, and it has been built using the LEGO NXT kit. To improve the compatibility between the robotic arm and the robot mobile, the LEGO NXT is programmed on LabVIEW [8], a trademark software of NI, to use the starter kit, which is a robot also distributed by NI. An Ethernet connection is used for communication between the PC and the mobile robot, while a Bluetooth connection is used for communication with the robotic arm [9].

This chapter describes, in Section 2, the global strategy used to design, implement and program the palletizer robot. The robot implementation and the A-start algorithm are explained in Section 3. Experimental results are presented in Section 4. Finally, Section 5 includes the conclusion and outlines future work.
