一种与移动机械臂与部分零件所受载荷相协调与运动结构外文翻译

一种与移动机械臂与部分零件所受载荷相协调与运动结构外文翻译 . 中文4729字 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) 21:227–242 . . A kinematically compatible framework for cooperative payload transport by nonholonomic mobile manipulators (2) 1 2 2 2 M. Abou-Samah, C. P. Tang, R. M. Bhattand V. Krovi (1) MSC Software Corporation, Ann Arbor, MI 48105, USA (2) Mechanical and Aerospace Engineering, State University of New York at Buffalo, Buffalo, NY 14260, USA Received: 5 August 2005 Revised: 25 May 2006 Accepted: 30 May 2006 Published online: 5 September 2006 Abstract In 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-manipulator's 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 schemes—leader-follower and decentralized control—are 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. Keywords Composite system-Hardware-in-the-loop-Mobile manipulator- Physical cooperation-Redundancy resolution-Virtual prototyping Kinematic collaboration of two mobile manipulators We now examine two variants of system-level cooperative control schemes—leader-follower and decentralized control—that can be created based on the individual mobile-manipulator control scheme. Leader-follower approach The 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 β). . . (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 approach The 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 manipulators with respect to the payload reference frame must be known apriori. Implementation framework We examine the design and development of a two-stage implementation framework, shown in Fig. 6, that emphasizes both virtual prototyping (VP) based refinement and hardware-in-the-loop (HIL) experimentation. Fig. 6 Paradigm for rapid development and testing of the control scheme on virtual and physical prototypes Virtual prototyping based refinement In the first stage, we employ virtual prototyping (VP) tools to rapidly create, evaluate and refine parametric models of the overall system and test various algorithms in simulation within a virtual environment. 3D solid models of the mobile platforms and the manipulators 4of interest are created in a CAD package, and exported with their corresponding geometric 5and material properties into a dynamic simulation environment. Figure 7(a) shows an example of the application of such framework for simulating the motion of a mobile 6platform controlled by an algorithm implemented in Simulink. However, it is important to note that the utility of such virtual testing is limited by: (a) the ability to correctly model and simulate the various phenomena within the virtual environment; (b) the fidelity of the available simulation tools; and (c) ultimately, the ability of the designer to correctly model the desired system and suitably interpret the results. . . Fig. 7 A single WMR base undergoing testing within the (a) virtual prototyping framework; and (b) hardware-in-the-loop (HIL) testing framework Hardware-in-the-loop experimentation We employ a hardware-in-the-loop (HIL) methodology for rapid experimental verification of the real-time controllers on the electromechanical mobile manipulator prototypes. Each individual WMR is constructed using two powered wheels and two unactuated casters. Conventional disc-type rear wheels, powered by gear-motors, are chosen because of robust physical construction and ease of operation in the presence of terrain irregularities. Passive ball casters are preferred over wheel casters to simplify the constraints on maneuverability introduced by the casters. The mounted manipulator arm has two passive revolute joints with axes of rotation parallel to each other and perpendicular to the base of the mobile platform. The first joint is placed appropriately at the geometric center on top frame of the platform. The location of the second joint can be adjusted to any position along the slotted first link. The second link itself is reduced to a flat plate supported by the second joint. Each joint is instrumented with optical encoder that can measure the joint rotations. The completely assembled two-link mobile manipulator is shown in Fig. 1(c). The second mobile manipulator (see left module of Fig. 1(b) and (d)) employs the same overall design but possesses a motor at the base joint of the mounted two-link arm. The motor may be used to control the joint motion along a predetermined trajectory (which can include braking/holding the joint at a predetermined position). When the motor is switched off the joint now reverts to a passive joint (with much greater damping). The motor is included for permitting future force-redistribution studies. In this paper, however, the motor is used solely to lock the joint prevent self-motions of the articulated linkage for certain pathological cases (Bhatt et al., 2005; Tang and Krovi, 2004). PWM-output motor driver cards are used to drive the gearmotors; and encoder cards monitor the encoders instrumenting the various articulated arms. This embedded controller communicates with a designated host computer using TCP/IP for program download and 8data logging. The host computer with MATLAB/Simulink/Real Time Workshop provides a convenient graphical user interface environment for system-level software development using a block-diagrammatic language. The compiled executable is downloaded over the network and executes in real-time on the embedded controller while accessing locally installed hardware components. In particular, the ability to selectively test components/systems at various levels (e.g. individual motors, individual WMRs or entire systems) without wearing out components during design iterations was very useful. Figure 7(b) illustrates the implementation of such a system on one of the WMRs. Numerous calibration, simulation and experimental studies . . carried out with this framework, at the individual-level and system-level, are reported in Abou-Samah (2001). Experimental results 9For the subsequent experiments, we prescribe the initial configuration of the two-module composite system, as shown in Fig. 8. Specifically, we position the two WMRs such that MP A is located at a relative position of , and with a relative orientation difference of with respect to MP B. For fixed link-lengths this inherently specifies the values of the various configuration angles as shown in Table 1. Table 1 Parameters for the initial configuration of the two-module composite wheeled system (see Fig. 8 for details) Link lengths of the articulation L 0.28 m (11 in) 1 L 0.28 m (11 in) 2 Relative angles of the configuration of the articulation L 0.28 m (11 in) 3 φ 333.98? 1 φ 280.07? 2 φ 337.36? 3 Offset between the wheeled mobile bases φ 128.59? 4 δ 0.00? 0.00 m (0 in) 0.61 m (24 in) Fig. 8 Initial configuration of the two-module composite wheeled system Leader-follower approach A straight line trajectory at a velocity of 0.0254 m/s is prescribed for the leader, MP B. Given a desired configuration of the manipulator arm, the algorithm described in Section 4.1 is used to obtain a desired trajectory for MP A. A large disruption is intentionally introduced by causing one of the wheels of MP A to run over a bump, to evaluate the effectiveness of the disturbance accommodation, detection and compensation.The results are examined in . . two case scenarios – Case A: MP A employs odometric estimation for localization as seen in Fig. 9, and Case B: MP A employs sensed articulations for localization as seen in Fig. 10. In each of these figures, (a) presents the overall -trajectory of {M} of MPA with respect to the end-effector frame {E} (that is rigidly attached to the {M} of MPB) while (b), (c) and (d) present the relative orientation difference, X-difference and Y-difference as functions of time. Further in both sets of figures, the ?Desired‘ (–– line) is the desired trajectory typically computed offline; and ?Actual‘ (–o– line) is the actual trajectory followed by the system, as determined by post-processing the measurements of the instrumented articulations. However, in Fig. 9, the (–x– line) represents the odometric estimate while in Fig. 10 it stands for the articulation based estimate (which therefore coincides with the ?Actual‘ (–o– line) trajectory). Fig. 9 Case A: Odometric Estimation of Frame M, used in the control of MP A following MPB . . in a leader-follower approach, is unable to detect non-systematic errors such as wheel-slip. (a) XY trajectory of Frame M; (b) Orientation versus Time; (c) X position of Frame M versus Time; and (d) Y position of Frame M versus Time Fig. 10 Case B: Articulation based Estimation of Frame M, used for control of MPA with respect to MP B in a leader- followe r approa ch is able to detect and correct non-sy stemati c errors such as wheel- slip. (a) XY trajecto ry of Frame M; (b) Orienta tion versus Time; (c) X position of Frame M versus time; and (d) Y position of Frame M versus time In Case A, the introduction of the disruption causes a drift in the relative configuration of the system which remains undetected by the odometric estimation. Further, as seen in Fig. 9, this drift has a tendency to grow if left uncorrected. However, as seen in Fig. 10, the system can use the articulation-based estimation (Case B) to not only detect disturbances to the relative configuration but also to successfully restore the original system configuration. Decentralized control approach . . In this decentralized control scenario, a straight line trajectory with a velocity of 0.0254 m/s is presented for the payload frame. As in the leader-follower scenario, a large disruption is introduced by causing one of the wheels of MP A to run over a bump. The algorithm is tested using two further case scenarios—Case C: Both mobile platforms employ odometric estimation for localization as shown in Fig. 11, and Case D: Both mobile platforms employ sensed articulations for localization as shown in Fig. 12. Fig. 11 Case C: Odometric estimation of frames M of MP A and MP B, used in the control of MP A with respect to MP B in the decentralized approach, is again unable to detect non-systematic errors such as wheel-slip. (a) XY trajectory of frame M of MP A; (b) XY trajectory of frame M of MP B; (c) Relative orientation, between MP A and MP B, versus time; (d) X distance, between MP A and MP B, versus time; and (e) Y distance, between MP A and MP B, versus time. (f) Sequential photographs of the corresponding composite system motion (as time progresses from left to right along each row) . . Fig. 12 Case D: Articulation based estimation of frames M of MP A and MP B, used for the control of MP A and MP B with respect to a payload-fixed frame is able to detect and correct non-systematic errors such as wheel-slip. (a) XY trajectory of frame M of MP A; (b) XY trajectory of frame M of MP B; (c) Relative orientation, between MP A and MP B, versus time; (d) X distance, between MP A and MP B, versus time; and (e) Y distance, between MP A and MP B, versus time. (f) Sequential photographs of the corresponding composite system motion (as time progresses from left to right along each row) In each of these figures, subplots (a) and (b) presents the overall trajectories of frames {M} of MP A and MP B respectively with respect to their initial poses. Subplots (c), (d) and (e) present the relative orientation difference, X-difference and Y-difference of frames {M} of MP A and MP B respectively as functions of time. Further in both sets of figures, the ?Desired‘ (–– line) is the desired trajectory typically computed offline; and ?Actual‘ (–o– line) is the actual trajectory followed by the system, as determined by post-processing the measurements of the instrumented articulations. However, in Fig. 11, the (–x– line) represents the odometric estimate while in Fig. 12 it stands for the articulation based estimate. In Case C, both mobile platforms use the odometric estimation for localization—hence as expected, Fig. 11 reflects the fact that the system is unable to detect or correct for changes in the relative system configuration. However the data obtained from the articulations accurately captures the existence of errors between the frames of reference of MP B and MP A. Thus, using the articulation-based estimation of relative configuration for control as in Case D allows the detection of disturbances and successful restoration of the original system configuration as shown in Fig. 12. Note, however, while the relative system configuration is maintained, errors relative to a global reference frame cannot be detected if both WMRs . . undergo identical simultaneous disturbances. Detection of such absolute errors would require an external reference and is beyond the scope of the existing framework. Conclusion In this paper, we examined the design, development and validation of a kinematically compatible framework for cooperative transport of a common payload by a team of nonholonomic mobile manipulators. Each individual mobile manipulator module consists of a differentially driven wheeled WMR retrofitted with a passive two revolute jointed planar manipulator arm. A composite multi degree-of-freedom vehicle system could then be modularly created by attaching a common payload on the end-effector of two or more such modules. The composite system allowed payload trajectory tracking errors, arising from subsystem controller errors or environmental disturbances, to be readily accommodated within the compliance offered by the articulated linkage. The individual mobile manipulators compensated by modifying their WMR bases‘ motion plans to ensure prioritized satisfaction of the nonholonomic constraints. The stabilizing controllers of the WMR bases could then track the recomputed ―desired motion plans‖ to help restore the system-configuration. This scheme not only explicitly ensured maintenance of the kinematic compatibility constraints within the system but is also well suited for an online sensor-based motion planning implementation. This algorithm was then adapted to create two control schemes for the overall composite system— the leader follower approach and the decentralized approach. We evaluated both approaches within an implementation framework that emphasized both, virtual prototyping and hardware-in-the-loop using the case-study of a two module composite system. Experimental results verified the ability of the composite system with sensed articulations to not only accommodate instantaneous disturbances due to terrain irregularities but also to detect and correct drift in the relative system configuration. The overall framework readily facilitates generalization to treat larger systems with many more mobile manipulator modules. Appendix A The kinematic constraint equations shown in Eq. (3) may be written in the general form as: (20) Then the velocity constraint equation can be written as: (21) The general solution to this differential equation is: (22) By appropriate selection of the initial conditions within the experimental setup, one can create the condition , i.e., exactly satisfying the constraint at the initial time, which then permits the constraint to be satisfied for all time. However, one could also enhance this process by adding another term to the right-hand-side of Eq. (21) as: (23) where Φ is a positive-definite constant matrix. This results in a first order stable system: (24) whose solution for any arbitrary initial configuration is: (25) . . In such systems, there is no longer a requirement to enforce since the solution exponentially stabilizes to regardless of the initial conditions. This feature could potentially be easily added to transform Eq. (5) to further improve overall performance, but was not required. References Abou-Samah, M. 2001. 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Cooperating multiple behavior-based robots for object manipulation. In 1994 IEEE/RSJ International Conference on Intelligent Robots and Systems. Whitney, D.E. 1969. Resolved motion rate control of manipulators and human prostheses. IEEE Transactions on Man-Machine Systems, MMS-10;47–53. Yamamoto, Y. 1994. Control and coordination of locomotion and manipulation of a wheeled mobile manipulator. Ph.D. Thesis, University of Pennsylvania, Philadelphia, PA. Yamamoto, Y. and Yun, X. 1994. Coordinating locomotion and manipulation of a mobile manipulator. IEEE Transactions on Automatic Control, 39(6):1326–1332. Footnotes 1(R indicates revolute joint. RRR indicates serial linkages connected by three revolute joints. 2(We denote ―desired ‖ quantities using superscript d in the rest of the paper. 3(Reference robot variables are denoted using superscript r and actual robot variables without any superscript for the rest of the paper. TM4(SolidWorks was the CAD package used for this work. TM5(MSC Visual Nastran was the dynamic simulation environment used for this work. 6(Simulink is the registered trademark of Mathworks. 7(xPC Target is a product of Mathworks. 8(MATLAB is a registered trademark of Mathworks. 9(Videos of experimental evaluation are available at . . 译文 一种与移动机械臂的部分零件所受有效载荷相协调的运动结构(2) 摘要:在本文中，我们研究了一种轮式机械手系统模块的控制结构，这是一种可以合理传递载荷而且符合运动学的结构。每个能独立运动的机械手都由装有差分驱动的轮式移动机器人组成，这种机器人在静态平面内有两个自由度。复合轮式的 方案 气瓶 现场处置方案 .pdf气瓶 现场处置方案 .doc见习基地管理方案.doc关于群访事件的化解方案建筑工地扬尘治理专项方案下载 有调节，侦测和修改瞬时的和相对的配置错误功能，这种方法是通过在多个移动机械臂的末端执行器上分布载荷形成的。在这里研究的用以控制动作结构，主要是为了保持系统内的所有运动约束(完整和非完整约束)，这种结构是符合运动学的。任意给定一个末端执行器的运动轨迹，每个独立机械手的双级分层控制器都能首先为轮式移动机器人的机座生成了一个符合运动学的轨迹，这种轨迹可以被底部控制器跟踪。两种不同的系统控制方案——主从控制方案和分散控制方案，是建立在个别可移动机械手的控制方案基础上的。两种方法都是在强调虚拟原型和环形回路硬件实验的框架内进行评估的。双模型系统的仿真和实验结果被用于突出本地传感器的快速调节，探测和修正相对配置错误的能力。 关键词:复合系统 环形回路硬件 移动机械手 物理协作 方案备份 虚拟原型 .4.移动机器人的两种协调运动 我们现在研究的是两种不同的系统级协调控制方案——基于独立运动机械手控制方案的主从式控制方案和分散控制方案 4.1主从控制方案的讨论 . . 第一种系统建模的方法是将移动机械手B中的移动平台和机械手A的末端执行器连接，如图所示。图4描述的是移动平台A的末端执行器是如何稳定的和移动平台B 连接的(由一个稳定的旋转角β分开)。 (15) 在这里，移动平台B起着主动件的作用，可以被控制着去遵循轮式移动机器人的可行性轨迹。所以，可以给定一个移动平台B的主动件轨迹 ，作为机械手的首选结构，等式(5)可以被这样描述: (16) 并且相应的等式(6)——(8)可被描述为: (17) . . 像这样，作为从动件的移动平台A的实际轨迹和推导出的速率就可以确定了。这种形式的主从控制方案可以用于控制受载荷的符合系统。 4.2分散控制方案的讨论 第二部分讨论的是移动机械手和它的末端执行器的受载荷部分，如图5所示。因此，这种受载荷结构的轨迹可以像上一节所讨论的，做以下描述:当，, 其中K=A,B时，移动平台有类似轨迹。这里等式(5)成立，且可以被写成这样: (18) 并且与之对应的等式(6)——(8)可以被写作: (19) 每一个双连杆机械臂要控制相应的，带负载的末端执行器结构。然而，受 负载的机械手上的附件位置必须是已知的。 .5.结构的落实 . . 我们讨论了一个如图表6所示的强调虚拟原型和半实物环形回路硬件实验的双平台结构的设计和开发。 5.1虚拟样本的改进 第一阶段我们在非虚拟的环境里采用虚拟样本工具来快速创建、评估和改进综合系统的模型参数，并测试不同的模拟算法。在CAD页面里创建机械手和移动平台的3D实体模型，并把相对应的几何和材料属性输出到动态模拟环境中。 图4 图解描述了主从控制方法:(a)图所示为三连杆机械臂的分析，(b)图所示为双模块组合系统。 图表(a)表达了一个运动的模拟应用实例，这种移动平台的模拟运动是由仿真应用中的算法控制的。但是，在这里必须注出一些重要的限制条件:(a)修改模型与模拟在非虚拟环境中虚拟现象的能力;(b)有效模拟工具的保真度;(c)设计器的正确系统建模和翻译结果的能力。 5.2环形回路硬件实验 我们采用环形回路硬件实验的方法随时可以快速控制电器机械手。每个单独的轮式移动机器人由两个带驱动的轮子和不带驱动的脚轮组成。习惯上我们选用齿轮驱动脚轮，因为这种方法可以使结构稳固，还可以减少操作. . 的谬误。相对轮式脚轮，我们首选球式脚轮作为从动轮的原因是它可以简化约束。安装好的机械手有两个被动旋转的关节，一个是旋转起来的时候和移动平台的中心线平行的关节，一个是旋转起来的时候和移动平台的中心线垂直的关节。第一个关节在移动平台顶部的旋转中心。第二个关节的位置可以沿第一个关节槽的位置任意调整。第二个连接是为了减少第二关节的支撑板。每个接头都装有可以测量旋转关节的光学编码器。图(c)表达的是装配有完整双连杆的机械手。第二种机械手(参见图表1左边的图(b)和(d))采用了同样的整体设计，但在双连杆手臂的关节处装有一个马达。这个马达可以控制关节沿着预定的轨迹运动(在指定位置的停止和启动)。当电机关闭的时候关节就又恢复到被动运动的状态(有强阻尼运动)。电机是在强制分配后被许可的。然而，在本文中，它仅单独用于关节的锁定以防止故障引起的自我动作。脉冲输出电机的驱动卡片被用于驱动齿轮型电动机，并且不同的关节型机械手都装有编码器。嵌入式控制器可以和有TCP/IP协议且有程序下载和数据存储的功能的主机通信。装有MATLAB/Simulink/Real Time Work软件的主机可以方便地用图形语言支持系统软件应用环境界面的开发。编译后的可执行文件通过网络下载，并在访问本地安装的硬件时，实时在嵌入式控制器里执行。特别是，有选择性的测试不同等级的系统元件的能力是非常有用的，这种在系统元件在设计中是没有重复部分的。图7举例解释了轮式移动机器人系统的执行情况。阿布萨玛赫(2001年) 报告 软件系统测试报告下载sgs报告如何下载关于路面塌陷情况报告535n,sgs报告怎么下载竣工报告下载 ，许多校准，仿真和实验研究在用户和系统框架下得到执行。 . . 图5 图标表达了分散控制的方案 (a)复合系统;(b)可被看成两个独立的二杆移动机械臂。 图6:研究和测试实体样板及虚拟样板控制方案的范例 图7: (a)图的虚拟样板结构是仅以测试经验为基础的轮式移动机器人，. . 图(b)是环形回路硬件的测试结构。 .6.实验结果 对于接下去的实验，我们按图表规定双模块系统的初始配置。特别的，我们规定装有坐标为x=0.00m(0in), y=0.61m(24in)的A移动平台和相对规定方向成角的B移动平台的轮式移动机器人的位置。这种固定长度的连接指出了如表所示的不同三角形结构的重要性。 6.1主从控制方案的讨论 B移动平台作为主动件规定了速率为每秒0.0254米的直线轨迹。给定要求的机械手臂结构，图表给定的算法用于获得指定的移动平台A的轨迹。一些严重的破坏主要是由于A移动台的一个轮子的碰撞引起的，这种A移动台用于估算探测，调整和修正效果。 图8:轮式双模块组合系统的初始设置。 研究的结果是这两个方案，如图，方案A里的移动台用里程计定位，方案B的移动台能识别关节的定位。在这些图表里总体的描述了带{E}型末端执行机构的轮式移动机器人的轨迹{M}，同时(b)、(c)、(d)图描述的是用于计算时间的不同的相对位置差，X位置差和Y位置差。更进一步说，. . 在这些图表里，“要求的”(用下划线标注的)指的脱机的预定轨迹，“实际的”(用线–o–标注)指的是系统下的实际轨迹，该轨迹是由关节处的尺寸经后处理得到的。然而，在图表9里，用–x–替代的部分，在图表10里代表了理论上的连接(所以和实际轨迹(划–o–线的部分)相符合的)。 . . 表1:轮式双模板复合系统的初始参数配置 关节的连接长度 0.28 m L 1(11 in) 0.28 m L 2(11 in) 0.28 m 关节的相对角度设置 L 3(11 in) φ 333.98? 1 φ 280.07? 2 φ 337.36? 3 轮式移动结构间的配置 φ 128.59? 4 δ 0.00? 0.00 m (0 in) 0.61 m (24 in) 图9:方案一，在分级控制方案里，作为轮式移动机器人B的从动件，轮式移动机器人A的控制结构M是不能探测到像车轮打滑这样的非系统性错误的。(a)图表示X、Y轨迹的坐标M，(b)图表示对时间的定位，(c)图表示时间坐标M的X位置，(d)图表示时间坐标M的Y位置。 . . 图10 :方案B，在分级控制方案里，和轮式移动机器人B对应的轮式移动机器人A的控制结构M，是可以探测到像车轮打滑这样的非系统性错误的。(a)图表示X、Y轨迹的坐标M，(b)图表示对时间的定位，(c)图表示时间坐标M的X位置，(d)图表示时间坐标M的Y位置。 事故引起了系统结构的相对漂移，这是在里程计里无法探测的。更进一步说，像如图所描述的，如果不加以纠正，这种漂移会有增加的趋势。然而，就像如图所示的，系统不但可以用这种基础衔接检测相对设置的干扰，还可以成功设置系统的初始设置。 6.2分散控制方案的讨论 在这种分散控制方案里，负载结构里已经出现了速度为每秒0.0254米的直线轨迹。作为分级控制方案，大的故障是由移动台A的轮子发生碰撞引起的。在使用另外两种方案的时候，这种算法得到了测试。方法C:移动台都采用区域范围内的里程计进行判断。方法D:移动台都采用区域内的遥感关节。 . . 图表11，方法C:在分级控制结构里，移动台A和移动台B的里程计结构，是不能探测像轮胎打滑一类的非系统性错误的。(a)移动台A的XY轨迹M, (b)移动台B的XY轨迹M，(c)随时间变化的，移动台A和移动台B之间的相对距离，(d)随时间变化的，移动台A和移动台B之间的X坐标，(e)随时间变化的，移动台A和移动台B之间的Y坐标,(f)相应的复合系统的运动序列照片(随时间的变化，从每一行的左边移动到右边)。 . . 图12:方法D:在分级控制结构里，移动台A和移动台B的里程计结构，是可以探测像轮胎打滑一类的非系统性错误的。(a)移动台A的X、Y轨迹M, (b)移动台B的X、Y轨迹M，(c)随时间变化的，移动台A和移动台B之间的相对距离，(d)随时间变化的，移动台A和移动台B之间的X坐标，(e)随时间变化的，移动台A和移动台B之间的Y坐标,(f)相应的复合系统的运动序列照片(随时间的变化，从每一行的左边移动到右边)。 在下列图表里，图(a)和图(b)描述的是移动台A和移动台B的初始状态的综合轨迹{M}，图(c)图(d)图(e)表达的是相对位置的差距，和时间变化的移动台A和移动台B的X坐标差和Y坐标差。更进一步说，在. . 这些图表里，“要求的”(用下划线标注的)指的脱机的预定轨迹，“实际的”(用线–o–标注)指的是系统下的实际轨迹，该轨迹是由关节处的尺寸经后处理得到的。然而，在图表11里，用–x–替代的部分，在图表12里代表了理论上的连接。 在方法C里，移动台使用距离测算来定位，如图11表达了一个不能探测和修正相对系统参数的变化的系统。然而，从精密连接中获得的数据包含了存在于移动台A和移动台B的错误。在方法D里，像这样用来检测关节的控制结构可以用来探测故障并恢复系统的初始设置。然而，当和系统相关的参数得到保持的时候，如果轮式移动机器人同时遭受许多干扰，全局结构里的相对错误就不能被检测到。在现有的框架范围内，外部错误的探测需要一个外部基准。 .7.总结 在本文里，我们研究了相对运动学里一种机械手的设计，研究和 证明 住所证明下载场所使用证明下载诊断证明下载住所证明下载爱问住所证明下载爱问 ，这种机械手具有不完全被限制的自由度并有载荷传递。每种独立的机械手都装有不同的驱动，在平面内，这种轮式移动机器人都装有具有两个自由度的机械手臂。一个具有复合自由度的实体系统可以由受载荷的多模块末端执行机构构成。复合系统允许有效载荷由于环境参数、单元控制器错误引起的跟踪误差， 通过连锁反应而快速做出调整。通过修改轮式移动机器人的预定运动方案以确保它的不完整约束。轮式移动机器人的稳定控制器通过计算预期运动方案，来起到恢复系统参数的作用。这种方案不仅确保了系统外的运动兼容性，也确保了在线运动方案的执行。这种算法适用于创建整体系统的两个控制方案，主从控制方案和分散的单元控制方案。我们评估这些方法的条件是不能含有强调双模块的系统中虚拟样机和环形回路硬件的执行机构。实验结果证实了复合系统测连接的能力，这种能力. . 不但包括不同地形造成的瞬时故障的调整，而且也包括了系统参数的修正。这种整体结构很快被推广到具有更多机械手的更大系统。 附录 运动学上关于约束的等式(3)可以被写成以下形式: (20) 然后，关于速度约束的等式可以被写成以下形式: (21) 解决差动问题的等式可以被写成以下形式: (22) 在实验之外的，充当条件选择的等式 , i.e.，这种含有复合要求的约束在开始时候是十分复杂的。但也可以增加另外一个等式: (23) 在这里Φ是正定的常数矩阵，该结果是一阶稳定系统: (24) 它的初始参数是: (25) 在这个方法里，在无视初始条件的前提下，解的指数时，不再需要用。 . . 这个等式很容易被引进而被转化为等式(5)，用来进一步提高整体的性能，但这不是必须的。 .