The Research And Test Of The Boiler Heat Exchanging Tube Inspection Robot

More than 80% electricity was supplied by thermal plant in China.The finned bearing heat-exchanger tube was the key equipment of the power plant.Accidents always occurs with this kind of tube for the worsening of the working condition,thus the generator group was forced to stop resulting in a great economic loss.The tubes were arranged in layer with complex architecture and the spaces among the the tube were small.It is difficult to inspect the inner tubes and only the flaws on the surface tube can be measured by sight at the present time in the world.A novel robot was manufactured that can be used to inspect the flaw in anywhere of the finned bearing heat-exchanger tube,and the methods how the detector can move safely in narrow space among the tubes were studied.A track-wheel type omni-direction moving mechanism was proposed.The robot can reach anywhere on the top tube surface both in X-direction and Y-direction while the robot attitude keep unchanged.A novel detector transfer arm was designed,it can carry inspection device into space among deeper layer tubes in a straight line,on the other hand it can be reelde in a disk so that the arm can act freely in boiler without interference with the tube and the boiler.Although all wheels were driven independently and the deflection angle can not be measured directly,the robot can run along the tube axis without deflection via cross-coupled coordinated controller based on load observation.Model parameters of the wheel servo system were identified via least squares technique in order to estimate the exact value of the system load and the identity results were tested.The running speed of every wheels were different even if their rotating speed were same because they were driven independently,there were interfere couple among the wheels,at the same time the run speed of the wheels were influenced by the arrange of the tube fins.PI feed forward controller based on load observation were designed in order to control every wheel speed,as a result the wheels running speed were not affected by fins arrange. A decoupled controller based on load observation was designed between front and back wheels at the same side of the vehicle body,the front and the back wheels can run not only at the same speed but also there was no interfere torque between them so the cross-coupled control on the robot vehicle can be realized only use one wheel on each side of the vehicle body.A fuzzy PI cross-coupled controller were designed to whole vehicle in order to assure the robot run in direction along the tube axis without deflection.