Control And Simulation Of Trajectory Tracking For Welding Mobile Robot Based On Backstepping

With the rapid economic development, industrial technology continues to progress, intelligence, information and digital are the trend of highly automated welding process. The development of modern shipbuilding, petrochemical industry and spaceflight industry, the important large-scale structures have been used more and more widely, in which a large number of welding work must be done in the field. Completely rely on the workers by hand or the well-known robot with 6 degrees of freedom have been already unable to meet the requirements of the welding of these large-scale welding structures. So the development of welding mobile robot with trajectory tracking suitable for the specially unstructured working environment has broad application prospects. The aim of this dissertation is to construct the control and simulation of seam trajectory tracking based on backstepping for grating constructions.First, select the best topological structure for seam tracking of grating constructions, establish the kinematic model of welding mobile robot: two driving wheels located on the right and the left of the body, two guide wheels located on the front and the back of the body, cross slider installed on the axis center of driving wheel, welding torch-point lined in the extension of driving wheel axis. Such a structure makes the driving wheel, body reference point and welding torch-point in the same line, the simple and clear position relationship makes the mathematical operation so succinctly.Then, introduce the virtual prototyping technology, create a virtual prototype model of welding mobile robot in the ADAMS software, define the role of the robot in various components, accurately define the relationship between the various components of the robot; and completely restore the structural characteristics, material factors, related to mechanical properties and simulation runtime of the model, implement the kinematics simulation of the model. Simplify the model, fix the cross slider and the body, on this premise, respectively carry out the kinematics simulation of seam for straight line and curve, verify the correctness of the model. The simulation result can be the foundation of control.In this dissertation, we use the backstepping foundation of control, the basic idea of it is to break down the complex non-linear system into the sub-system which does not exceed the number of system order, then design Lyapunov function and virtual control amount of intermediate for each subsystem, "backstepping" to the entire system, until complete the design of control laws. Combined the principle of backstepping and the kinematics model of welding mobile robot, we can design the backstepping controller for welding mobile robot.Finally, using the following softwares: ADAMS and MATLAB, we simulate the movement control of the designed wheel's robot. We attempt to find a way of simulation by using the same model of mechanical model and control model. We build the mobile robot model in ADAMS, we regard it as a model module in MATLAB, used the redesigned backstepping controller for welding mobile robot when simulate with ADAMS and MATLAB. In this dissertation, we simulate the motion control of mobile robot's seam tracking in different condition of line(y=x) and curve( x 2 + y2=4502). Simulation results show that the tracking trajectory converges to the desired trajectory, the backstepping foundation of control can get a satisfied result.