Research On The Micro-Polishing-Robot With Vacuum Cup

1.IntroductionIn recent years, with the development of automobile industry, electronics industry, aeronautics and astronautics industry and some new high-tech industries, higher and higher requirements are made for quality and efficiency in machining die and mould with free-curved surfaces. But, regardless of which one kind of shape processing method,all must be skiving, polishing after shape process to obtain conforms to the request work piece surface quality.Regarding the large-scale mold free-form surface, it needs a large polishing equipment to polish based on the traditional processing,the cost is large. Meanwhile there is a scope for processing accuracy, stiffness, stability and rapid movement numerous technical difficulties. But at present, processes of precision machining die and mould with free-curved surface still depends mainly on the handwork of skilled workman. Because the handwork is low efficiency and unstably machining quality, it is difficult to adapt with requirements of free-curved surfaces for low cost,short period and high quality.Many country have researched new machining method early or late for resolving the problem in the finish machining of the large-scale mold free-form surface. The subject present a new technology idea that use the small finishing equipment for the processing of large free-form surface.2.Noumenon design of the Micro-Polishing-RobotMicro-robot research is due in large parabolic surface coverage for grinding and polishing operations. Therefore, in order to ensure normal work, we must have the ability to operate adaptive institutions, the ability to span the obstacles and the ability to process the surface exactly. This paper from a large body of literature data and the operating current mobile robots, design a Micro-polishing Robot with vacuum cup and cross frame. This robot have be installed a tools of 3-DOF. So it can achieve the exactly machining to the every segment of the large free-curved surfaces. The structure on Micro-polishing Robot is innovation, as shown in figure 1: The robot move on the large free-curved surfaces via the cross frame.In special instance, for example, the surfaces is plane, it can accomplish machining in high efficiency. But commonly, in order to improving the quality of the part difficult to process, we design the tools system which have 3-DOF. Establishing a reference frame regard the cross frame as XYplane and upturn is positive of Z, well then the tools could move relative to Z and circumgyrate relative to X and Y. The structure of tools system is shown as figure 2 3.Kinematics simulation and dynamics simulation of robotWe use D-H method to solve the problem of robot kinematics, first of all, established the coordinate system, as shown in Figure 3,Finally, obtained the bit-owned transformation matrix is as followed,According to the tool′s target position and orientation equal with the end of homogeneous transformation matrix, as followsWe can obtain inverse kinematics of this robot. Inverse Kinematics can be diversity, and the methods for solving is different, even, ti may be no solution.If the x? as the generalied velocity of the tool system, q? as the generalied velocity of the joints, there are In which J (q) is called Jacobian matrix of the robot tool system, Above all, we predigest the system in order to easy to expatiation.We obtained the kinetic expression when the robot tool rotation due to Lagrangian bases on in this instance the moving system equivalent to 1-DOF system. In the expression,"I"is moment of Inertia of the part rotation,"F"is rotational torque.This is kinetic expression when robot moved in XY plane. In it,"m"is the quality of moving part."F"is the driving force moving.This also reflects the simple structure of the robot characteristics.4.Robot path planningIn this paper, we research robot path planning based on the complete coverage. First of all, choosing the beginning of the movemonet direction according to the energy of the robot, and introduced the general principles of plot out the subbranch.Bases on this robot′s own characteristics, we bring forward a new way to walk, overcomed the intermittent when framework robot moved, greatly enhanced the efficiency of processing. Manner of walking robot as shown in Figure 4.Further improve the division of the sub-regional issues bases on the characteristics of the robot′continuous process. Namely, check the length of the region as a tool grinding head several times the diameter of the whole form. This can take full advantage of mobile robots for the characteristics of uninterrupted moving. 5.The robot motion simulation based on ADAMSCompletion of a three-dimensional solid modeling software used CATIA, and import to ADAMS for analysis of simulation exercise. Visual observation of body movements whether meet the design requirements, and measured the area of the joint driving force moment in order to make a reference for choose the motor.Figure 5 is the tool′displacement, velocity, acceleration curves and driving force behind the curve when the tool move with cross frame.According to the motor-driven power equal to lead screw′s output power, can be calculated that this part of the motor could meet the job requirements.Figure 6 is the tool′displacement, velocity, acceleration curves and driving force behind the curve when the tool move upward. The same, can be calculated that this part of the motor could meet the job requirements.