Research On A New Robot System For Autonomous Grinding

To achieve the polishing aim which a large freeform surface is grinded with a micro device, the peculiarity that mobile manipulator had better operation flexibility and expands mobile robots working space is integrated. These key technology that the mechanism polish a large freeform surface with autonomous task is researched in this paper, it include 3D reconstruction of free-form surfaces and localization method, kinematics and dynamic of the 5-TTRRT mobile robot, motion planning and motion controlling, compliance control.First, a kind of 3D reconstruction of free-form surfaces and localization method about to be prepared grinding is studied when the 5-TTRRT mobile robot move on the a large freeform surface. Utilizing monocular vision with line structured light technology, a 3D reconstruction and localization algorithm is put forward, then extracting the boundary of reconstructed of free-form surface, acquiring position and orientation of to be grinding in robot coordinate system.Next, an integrated kinematics model is built based on the mechanical structure and motion properties of the 5-TTRRT mobile manipulator. In addition, its dynamic model is deduced by Lagrangian formalism. The study results described above offer important technique foundations for the following motion planning designs and control. Meanwhile, the 5-TTRRT modeling dynamics was set up with Lagrange approach, and research was done on dynamic coupling between directional-motion model. The relationship for rate, acceleration and coupling was achieved via many simulation experiments under different conditions, the dynamics based on the relationship for ADAMS moving along circular curve track were simulated.Then, According to the characteristic reconstructed of free-form surface, analyzing subdivision planning method and grind, a subdivision algorithm with the 5-TTRRT mobile manipulator is put forward. The position and orientation and motion planning are analyzed, transverse movement programming method and longitudinal movement programming method is put into use with about 5-TTRRT mobile manipulator. longitudinal movement programming makes polishing tool move in a 2-D space of one line movements and a turn movement in grinding free-form surfaces by robot. transverse movement programming makes grinding tool move in a 3-D space of one line movements, a wave movements and a turn movement.The complete dynamics model is set up, the PD+feedforword control structure and tactics is built with position control in the trajectory tracking. The trajectory of 2D circular arc tracking and control were simulated, the simulate result is indicated structure simplicity, likely realized. It is the position controlling in the next impedance control.By analyzing the passive distortion structure and the active structure in 5-TTRRT control system, apply the theory of hybrid force/position control, force control is combined with position control in the same structure by impedance control. Analyzing the a impedance control method based on position in regular target impedance, it is simulated. With imitating grinding according to by hand, the adjusting target impedance is studied. A fuzzy self-adjustment impedance based on target impedance is designed, and simulating the method, the result is indicated the force tracking based on known condition parameter can be achieved preferably.Finally, hardware experiment system of 5-TTRRT was set up to do a serious of experiments about polishing operation. With position and orientation of polishing tool, the influencing factor about grinding effect is analyzed, better position and orientation parameters is acquired, the result of the experiment had proved the efficiency of mobile manipulator positioning, rationality of motion planning, and the efficiency of hybrid force/position control and route planning algorithm.