On The Kinematics And Dynamics Of Flexible Coordinated Manipulators

The coordination of robots and flexible manipulators are advanced topics in the robotics research. In the field of robot cooperation, most of works were limited in rigid robots so far. Compared with rigid ones, flexible robots are provided with the advantages of high speed, heavy payload and light weight. However, the large error, elastic vibration and other drawbacks due to the elastic deformation of flexible links can not be neglected in flexible robots. The coordination of flexible robots present the way to overcome these disadvantages, which has abstracted some attention and is being developed in recent years.In this dissertation, on the integration of flexible manipulator and coordinated robots, the cooperation of flexible manipulators manipulating rigid loads is studied in such aspects as system dynamic modeling. system inverse dynamics, numerical simulation, manipulability and control schemes.Firstly, two characteristics of flexible coordinated robot system have been recognized different from the coordinated system of rigid robots, i.e.i) The kinematic coordination constraints in the cooperation system of rigid robots will not hold true for that of flexible ones;ii) There exists coupling effect between the kinematics and dynamics of flexible cooperative system.Based on these properties, the nominal rigid configuration, rigid configuration and actual configuration have been defined, respectively. By applying the Finite Element Model, the kinematic and dynamic coordination constraints are then derived for coordinated flexible manipulators manipulating the rigid load with zero d.o.f. and the open-loop rigid load with one d.o.f., respectively. The dynamic equations of system have been established and the inverse dynamic algorithm has been presented. The influences of different basic configurations of solution have also been discussed through numerical simulation.Secondly, the kinematic and dynamic constraints of coordinated flexible manipulators manipulating a rigid four-bar linkage have been derived from the differential relationships of kinematics within the internal links of linkage. The dynamic equations of system have been governed consequently. Based on theiiistandard assignment, the general dynamic equations have been then obtained for the coordinated flexible manipulators manipulating multi-loop rigid load with multid.o.f., which is useful to establishing the virtual prototype and designing simulation software of such system.Thirdly, based on the geometrical differential constraints and force balancing constraints of the coordinated flexible manipulators, the mutual relationships between the kinematic and dynamic parameters in static configuration have been presented. The manipulation stiffness of the coordinated system has also been proposed. The manipulability of the flexible robot system has been then analyzed in two aspects:i) The global characteristics in the manipulation workspace based on the manipulation stiffness;ii) The local property of the reachable boundary of generalized forces.A simulation of two coordinated manipulators manipulating a rigid load is presented as an example.Finally, the dynamic control scheme for compensating the position and orientation errors of the grasped load has been developed to complete the assignment of CP trace for two coordinated flexible manipulators manipulating a rigid load. The improvement on manipulating precision of grasped load has been achieved by feeding back the transformation of position and orientation errors of the grasped load to scheme the compensative input angle of each joint. The effect of the gain in forward channel on the stability and result of control scheme have also been illustrated by numerical simulation.A comprehensive study has been completed in this thesis, which paves the way to the further development of flexible cooperating robots.