外文翻译译文题目 一种与移动机械臂的部分零件所受载荷相协调的运动结构（2） 原稿题目 A kinematically compatible framework for cooperative payload transport by nonholonomic mobile manipulators（2） 原稿出处 Auton Robot (2006) 21:227242 A kinematically compatible framework for cooperative payload transport by nonholonomic mobile manipulators （2）M.Abou-Samah1, C.P.Tang2, R.M.Bhatt2and V.Krovi2(1)MSC Software Corporation, Ann Arbor, MI48105, USA(2)Mechanical and Aerospace Engineering, State University of New York at Buffalo, Buffalo, NY14260, USAReceived: 5August2005Revised: 25May2006Accepted: 30May2006Published online: 5September2006AbstractIn this paper, we examine the development of a kinematically compatible control framework for a modular system of wheeled mobile manipulators that can team up to cooperatively transport a common payload. Each individually autonomous mobile manipulator consists of a differentially-driven Wheeled Mobile Robot (WMR) with a mounted two degree-of-freedom (d.o.f) revolute-jointed, planar and passive manipulator arm. The composite wheeled vehicle, formed by placing a payload at the end-effectors of two (or more) such mobile manipulators, has the capability to accommodate, detect and correct both instantaneous and finite relative configuration errors. The kinematically-compatible motion-planning/control framework developed here is intended to facilitate maintenance of all kinematic (holonomic and nonholonomic) constraints within such systems. Given an arbitrary end-effector trajectory, each individual mobile-manipulators bi-level hierarchical controller first generates a kinematically- feasible desired trajectory for the WMR base, which is then tracked by a suitable lower-level posture stabilizing controller. Two variants of system-level cooperative control schemesleader-follower and decentralized controlare then created based on the individual mobile-manipulator control scheme. Both methods are evaluated within an implementation framework that emphasizes both virtual prototyping (VP) and hardware-in-the-loop (HIL) experimentation. Simulation and experimental results of an example of a two-module system are used to highlight the capabilities of a real-time local sensor-based controller for accommodation, detection and corection of relative formation errors. KeywordsComposite system-Hardware-in-the-loop-Mobile manipulator- Physical cooperation-Redundancy resolution-Virtual prototypingKinematic collaboration of two mobile manipulatorsWe now examine two variants of system-level cooperative control schemesleader-follower and decentralized controlthat can be created based on the individual mobile-manipulator control scheme. Leader-follower approachThe first method of modeling such a system considers the midpoint of the mobile base (MP B) of the mobile-manipulator B to be rigidly attached to the end-effector of mobile manipulator A, as depicted in Fig. 4. Figure 4(b) depicts how the end-effector frame E of MP A is rigidly attached to the frame at MP B (separated by a constant rotation angle ). (15)Fig. 4 Schematic diagrams of the leader-follower scheme: (a) the 3-link mobile manipulator under analysis, and (b) the two-module composite system MP B now takes on the role of the leader and can be controlled to follow any trajectory that is feasible for a WMR. Hence, given a trajectory of the leader MP B , and the preferred manipulator configuration of , Eq. (5) can be rewritten as: (16)and correspondingly Eqs. (6)(8) as: (17)Thus, the trajectory of the virtual (reference) robot for the follower MP A , and the derived velocities can now be determined. This forms the leader-follower scheme used for the control of the collaborative system carrying a common payload. Decentralized approachThe second approach considers the frame attached to a point of interest on the common payload as the end-effector frame of both the flanking mobile manipulator systems, as depicted in Fig. 5. Thus, a desired trajectory specified for this payload frame can then provide the desired reference trajectories for the two mobile platforms using the similar framework developed in the previous section by taking and , where . This permits Eq. (5) to be rewritten as: (18)Fig. 5 Decentralized control scheme implementation permits the (a) composite system; to be treated as (b) two independent 2-link mobile manipulators and correspondingly Eq. (6)(8) as: (19)Each two-link mobile manipulator now controls its configuration with reference to this common end-effector frame mounted on the payload. However, the locations of the attachments of the physical