The Design of Hardware for Remote Control System of the Manipulator

Transcription

1 The Design of Hardware for Remote Control System of the Manipulator Ing. Michal Hammerschmiedt, Department of Agricultural, Food and Environmental Engineering, Faculty of Agronomy, Mendel University in Brno, Ing. Marcel Vytečka, Ing. Jan Kolomazník, Department of Informatics, Faculty of Business and Economics, Mendel University in Brno, Abstract This article deals with the design of electronic circuits of the remote control system of the industrial manipulator Katana. The main goal is to create a complex solution, which will be able to switch the power of the manipulator on and off, to change the intensity of illumination and to detect changes of power supply (e.g., power drop). The main aim of this project is to enable remote control of the industrial manipulator Katana. Simple manipulation task is described in the end of this article. This task is used as a demonstration of using remote control system. The task is based on an image processing algorithm. This algorithm finds predefined markers and manipulate with the prototypes of figures according to calculated coordinates. Key Words Katana, Remote control, Computer vision, Control Web, DataLab Introduction Hundreds of thousands Czech crowns was invested into Katana manipulator. Main goal of our project was increasing work load of the manipulator but safety was also important condition for final solution. Protective cage is a part of our solution and lights and cameras are mounted on the ceiling of the cage. Lights and main power of the manipulator are controlled by the remote control system, which is described further in this article. Dr. Carwyn Jones and his team had solved similar problem. They had made Controlling a Robotic Manipulator for Nuclear Decommissioning and used NI CompactRIO hardware, NI LabVIEW system design software, and the NI LabVIEW Robotics Module to develop a cost-

2 effective, safe, and reliable system that provides accurate remote control of a heavy-duty manipulator in an environment that is otherwise inaccessible to humans (Jones, 2013). Company Kraft Telerobotic is making Grips with remote task performance for hydraulic manipulator for use on both manned and remotely operated vehicles. The design of the Grips makes it a good choice for many applications. Intuitive master/slave control allows even an inexperienced operator to perform work tasks with human like motion and speed. Their solution is used in mini submarines, telerobotic and experimental NASA HazMat vehicle. (krafttelerobotics.com, 2013) Objectives and methodology The main goal of this project has been achieved by creating remote control of industrial manipulator Katana. Safe control of the working space was the main condition of the whole project. Manipulator Katana is used in the academic environment for teaching students or preparation for a student thesis. Therefore, there is a major aim to allow as many students to work as possible with the machine in the classroom. DataLab IO2 is used for electric equipment and monitoring electrical variables in this project. Those devices are produced by Moravian instruments. This company produces devices for automation (IO modules, industrial computers, industrial cameras, etc.). The IO device is designed for maximum 10A power supply load and contains a switching power supply for LED and DataLab IO2. The main parts of our device are two devices DataLab IO2. DataLab IO2 is an industrial input / output DataLab IO that is designed to work with the host computer, which provides measurement (reading) and set (write) variables. Units are available in versions with: USB communication interface (DataLab IO / USB), Network Interface Ethernet (DataLab IO4/ETH) or the serial interface RS-485 (DataLab IO4/COM). These units communicate with the computer over very fast serial bus standard USB, which has become an universally recognized standard and replaces the aging serial and other interfaces (Jeniš, 2013). This interface provides users many advantages: - Standard and universal prevalence - High transfer rate (for USB 2.0 at 480 Mb/s)

3 - The communication response between the unit and the host computer is about 0.3ms for USB Automatic configuration of the unit, including installation of drivers. The proposal is made of consistent modular units. The units have open positions for insertion of input / output modules for the needs of the application and this can be combined with different modules (Moravia instrument, 2013). Control application is developed in Control Web software. Application allows controlling the lights and Katana through the Datalab IO2 device. Images from the camera are processed through the OpenCV library or another kind of software for work with the cameras such as VisionLab. There are tasks developed especially for presentation of the results and also education. It uses OpenCV library and "Katana native interface" libraries (C++ language) for manipulating with the prototypes. Results First DataLab IO2 is equipped with two digital output relay modules capable of switching up to 230 V AC and 30 V DC at currents up to 3A. The second IO2 module is equipped with digital input / output. The 8 LED strips, that are used to illuminate the space, and controlling power relay for power socket which used by the mechanical arm Katana are controlled through IO2 and digital outputs with relays. The second IO2 module consists of digital inputs/outputs that are used as an analytical element to determine when to turn on the UPS, etc. Both IO2 modules are connected to the control computer via USB. The Fig. 1 shows a schema of power circuits that shows the involvement of DataLab. DataLab operating with output ports includes the power switching relay, which can be more loaded than module DataLab.

4 1 : The schema of the power circuits The Fig. 2 shows the internal and external form of the whole module. Components are placed into Micro ATX PC case for encapsulation and thus enhance the safety of the whole solution. On the Fig. 2 part a) are shown circular connectors for connecting LED stripes, circular connectors for monitoring power etc., switching electrical outlet for Katana and two USB to connect DataLab to control PC. Simple manipulation task serves for presenting the solution of the whole project which is based on image processing and controlling the Katana manipulator. The camera processing images during the first part of the program is placed right above the working space. Algorithm then tries to find markers, which are on the top of the objects, and identify their positions. If algorithm finds one or more markers, it will transfer their positions from the camera coordinates system into Katana coordinates system, seen on Fig. 3. If there is no marker detected, program will keep searching. Computed coordinates of the objects are used for manipulation with them. Manipulator even sorts the objects into the classes. Class of the objects could be either white or black. Manipulator is programmed to place them into particular crates.

5 2 : The HW module a) back side of the case b) inner look 3 : Manipulation task and screenshot from camera Discussion Presented solution allows students and academic staff to work with the manipulator any time and place. Application developed in Control Web software allows controlling the lights, cameras and main power to the manipulator. DataLabs IO2 used for this functionality has more than 4 free I/O slots. It is possible to add some functionality if required.

6 Whole system can be improved by adding a small conveyor into the protective cage. Spectrum of possible tasks would be much wider and static tasks would be transferred into dynamic tasks. Conclusion Final solution allows greater load of the manipulator Katana. Students can use the remote control system from their personal computer. The main product of this project is a protective cage that allows not only safer handling of objects but also better placement of cameras for sensing area around the manipulator. Different lighting of the working space is possible by switching the LED strips. Acknowledgments Published results were acquired using the subsidization of the Ministry of Education, Youth and Sports of the Czech Republic, research plan IGA MENDELU MP 5/2013 Achieving effective utilization of the manipulator by introducing remote control system. References JENIŠ, J., 2012: Remote access to workstation of robot Katana. Brno. Cited from: e=1. Bachelor thesis. Mendelu. Thesis supervisor Dr. Ing. Radovan Kukla. JONES, C., 2006: National Instrument. JAMES FISHER NUCLEAR LTD. National Instrument [online]. [cit ]. Cited from: KRAFT TELEROBOTICS, 2013: Kraft telerobotics [online]. [cit ]. Cited from: MORAVIA INSTRUMENT, 2013: Moravia instrument [online]. [cit ]. Cited from: