In Section 2 related work is described。 In Section 3, an overview of the proposed system is presented。 Implementation of the Android application, 3D modeling of industrial robot Lola 50 [6], remote communication, and the structure and functionalities of the real-time control system are also described in this section。 The application of the developed system and obtained results are shown in Section 4。 A discussion about the advantages of the proposed solution compared to the existing solutions is given in Section 5。 The concluding remarks are given in Section 6。

2RELATED WORK

2。1 PC-based Applications in Robotics

The majority of robot manufacturers and many independent software vendors offer graphical environments in which users, namely developers and system integrators, can design and simulate their own manufacturing projects [7]。 RobotStudio from ABB Robotics [8] is an offline robot programming and simulation tool that enables robot programming on a PC without the need to interrupt production。 RobotStudio provides tools to increase the profitability of the robot system by providing training, programming and optimization without disturbing the manufacturing process。 Another example is the KUKA SimPro robot simulation software for creating 3D layouts for systems with KUKA robots [9,10]。 This simulation package includes a program called KUKA OfficeLite that generates KUKA robot commands。 Roboguide is a tool for simulation of work environment of the robot on the PC [11]。 It is used by the system designers and in the production process。 It is capable to check the interference between the robot and other objects, to control different operations by means of simulations, and to monitor the current status of the robot。

2。2Wireless Communication

Android devices, but also the other smart devices [12], provide different communication interfaces, such as Wi-Fi, Bluetooth, USB, and different types of integrated sensors, such as accelerometer, gyroscope, compass and GPS [13]。 Currently the wireless scene is held by two standards, the Bluetooth and the IEEE 802。11 (Wi-Fi) protocols, which define the physical layer and the medium access control (MAC) for wireless communications over a short action range (from a few up to several hundred meters) and with low power consumption (from less than 1 mW up to hundreds of mW)。 Bluetooth is mainly oriented towards connections between close-connected devices, as a substitute for data transfer cables。 IEEE 802。11 is devoted to connections among computers, as an extension or substitute for cabled LANs [14]。 Bluetooth technology is useful when transferring information between two or more devices that are near each other and speed is not an issue, such as telephones, printers, modems and headsets (from 10 cm up to 10 m) [15]]。 Wi-Fi enables a faster connection, better range from the base station, and better security (if configured properly) than the Bluetooth。 Comparison characteristics of those two wireless protocols are given in Table 1。

As it was necessary to implement an application that enables control of industrial robot at a great distance, in the case where the real machine cannot be visible and where monitoring is achieved through the 3D model movement or by drawing the trajectory of its end effector in real time, the Wi-Fi IEEE 802。11 protocol was chosen for the implementation。

Table 1。 Comparison of Bluetooth and Wi-Fi protocols

Bluetooth Wi-Fi

Frequency band 2。4 GHz 2。4 GHz, 5 GHz

Nominal range 10 m 100 m

Maximum one-way

data rate 732 kb/s 31。4 Mb/s

Maximum signal rate 1 Mb/s