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Application of Tele-control Hiroto Kato, Satoshi Ueki, Akihiro Kaneshige Toyota national College of Technology Slide 2 Outline Background Control system o Master o Slave o Block diagram Experimental result o Reaction force o Overhead tele-control Summary Slide 3 Background of this research Tele-control is an effective method for operating in hazardous environment and for remote operation. There are many way of application, such as followings. By combining tele-transport control system which has different shape Master/Slave system, it is expected to extend the range of application. Robot arm in the space JAXA HP: http://rexj.web.fc2.com/RJ/rex4.html Remote operation using da vinci engadget HP:http://japanese.engadget.com/ 2009/04/09/da-vinci/ Slide 4 Background of this research Overhead crane It is the one of the most useful transport systems, because it is simple and it can cover a wide working area. Besides There are many accidents caused by human errors. An expert operator is indispensable to control an overhead crane. It is expected to control overhead crane from remote place safely and easily. Overhead crane (Toyohashi University of Technology ) Slide 5 The purpose of this research We configure a remote transportation system for an overhead crane using the internet as a communication line. The transport system shall be easy-controlled system for operators. Cooperation with such a transport system will provide many application of tele-operation. Slide 6 Essential elements for overhead crane tele-control system Stability Time delays on the internet causes serious problem with stabilizing the control system. The design method Miyoshi* proposed for stabilizing tele-control system is adopted. Ease of use of the transport system Difficulties of controlling overhead crane are often caused by swing of the transferred object. We configure a transport system which an operator can feel the swing of the rod instinctively. *T. Miyoshi, K. Terashima, and M. Buss, 2006, A Design Method of Wave Filter for Stabilizing Non-Passive Operation System, pp. 1318-1324, IEEE Int. Conf. on Control Applications. Slide 7 Overhead crane tele-control system Without swing MasterSlave Internet and a controller With swing Slide 8 Master arm 1 degree of freedom arm shown is used as a Master. The arm is only able to rotate. Arm Strain gage: observe the strain value of the arm Motor driver and strain amp Encoder : observe the angle of the arm Slide 9 Overhead crane (Slave) Slave is an automatic overhead crane system which transfers an object with the cart that can move in the direction of X. The swing angle of the rod is measured by a laser sensor fitted to the table of the cart. Cart Rod Object Laser sensor Rod Slide 10 Block diagram of the control system The stability of this system is verified according to small gain theory. Tele-operator side Operator side Internet Phase-lead compensator Wave filter Slide 11 Tele-control experiment Condition of the experiments The experiment was held between Toyota National College of Technology (T.N.C.T) and Toyohashi University of Technology (T.U.T) using internet. There is a straight-line distance of approximately 50 km. Time delays during the experiments were around 40ms. The purpose of the experiments We confirm following 2 aspects through the experiments. (1) The operator feels the swing of the rod as a reaction force. (2) The crane is controlled according to operators order. Slide 12 Reaction force by the swing Method to verify the reaction force Make the transferred object swing by eternal force. Slave Fasten the end of the arm by grasping it with human hands. Master Operator Arm Object Crane External force Slide 13 Reaction force by the swing The reaction force changed depending on the weights of the operators arm and force adjustment. The reaction force with the same frequency as the swing was made in the Master. Reaction force Swing of the rod Slide 14 Overhead crane tele-control Experiment The operator tried to transfer the object to a distance of 1.3m from the start point. The operator watched the web camera and checked how the overhead crane moved while he operated overhead crane. Slide 15 Overhead crane tele-control There are delays which depends on the communication line between the ordered speed and the crane speed, however, The cart of the overhead crane moved at almost the same speed as the operator ordered. Speed order Crane speed Verification of speed control Slide 16 Verification of performance Position of the object Swing angle of the rod The operator was able to transfer the object on the target place. 1.3 Slide 17 Summary We designed an overhead crane tele-operation control system that can use the internet for communication. The system can be speed controlled by a remote operator and bring the swing of rod as a reaction force to the Master. These findings were proved by the demonstration between T.U.T and T.N.C.T. By using transport tele-control system, we expect to be able to extend the use of telecontrol. Slide 18 Acknowledgement The author would like to thank Prof. Dr.-Eng. Martin Buss of Technical University Munich for his cooperation. Slide 19 Slide 20 Verification of communication First, we checked the condition of the network as following. T.N.C.T T.U.T 1. Send a triangle data to T.U.T2. Receive the triangle data 3. Return the data 4. Receive the data and compare with the data of step 1. Internet Slide 21 Verification of communication Triangle data Time delay Communication seems to go smoothly, since the shape of both the sent and received triangle data is almost the same. There are constant time delays of approximately 40ms. Sending data Receiving data Slide 22 Transfer function of Master + - The block diagram of Master Slide 23 Transfer function of Slave Slide 24 Phase lead compensator Slide 25 Verification of stability The amplitude ratio exceed 0 and the gain exceed 1 around 7 rad/s Slide 26 Wave filter The gain doesnt exceed 1 and the system becomes sable