空間機械手的跟蹤捕捉操作

1、.：.；畢業(yè)設(shè)計外文資料翻譯題 目 空間機械手的跟蹤捕捉操作 學(xué) 院 機械工程學(xué)院 專 業(yè) 機械工程及自動化 班 級 機自0917班 學(xué) 生 廉開發(fā) 學(xué) 號 20210421170 指點教師 蘇東寧 二一 三 年 四月 一 日 Tracking Trajectory Planning of Space Manipulator for Capturing Operation Panfeng Huang1; Yangsheng Xu2 and Bin Liang3 College of Astronautics, Northwestern Polytechnical University, Chi

2、na 2 Department of Automation and Computer-Aided Engineerging, The Chinese University of Hong Kong, Hong Kong Shenzhen Space Technology Center, Harbin Instute of Technology, China Abstract: On-orbit rescuing uncontrolled spinning satellite (USS) using space robot is a greatchallenge

3、for future space service. This paper mainly present a trajectory planning method of space manipulator that can track, approach and catch the USS in free-floating situation. According to the motion characteristics of USS, we plan a spiral ascending trajectory for space manipulator to approach towards

4、 USS in Cartesian space. However, it is difficult to map this trajectory into the joint space and realize feasible motion in joint space because of dynamics singularities and dynamics couple of space robot system. Therefore, we utilize interval algorithm to handle these difficulties. The simulation

5、study verifies that the spiral ascending trajectory can been realized. Moreover, the motion of manipulator is smooth and stable, the disturbance to the base is so limited that the attitude control can compensate it.Keywords: Space manipulator, tracking trajectory planning, interval algorithms, polyn

6、ominal spline functionIntroductionThis paper deals with a special problem oftrackitrjectoryplanningofspacemanipulatofor capturing the uncontrolled spinning satellites. On-orbit capturingisachallengeworkforspacerobotsystem in the future space service. The space robot science has gotten big progress i

7、n the pastdecade.T herefore, on-orbit service for uncontrolled satellite will be a main application of space robot in orderreduce the space cost in the future. When human being launched the first space robot and operated itto accomplish the space mission, space robot began to be utilized in differen

8、tspacetasks. Nowadays space robots are aiding to construct and maintain the InternationalSpaceStatio andservicingthspace telescope. Therefore space robotic servicing forsatellitsuchrescue,repairrefuelling and maintenance, promise to extendsatellitelifeandreducecostsmakesitoneofthemostattractiveareas

9、ofdevelopingtechnology.Spacerobots are likelytoplay more and more important roles insatelliteservicingmissionandspaceconstructionmission in the future. The approach ancaptureoperation must be solved firstly in order to accomplish all these missions. A well known space robot, the Shuttle Remote Manip

10、ulator System (SRMSorCanadarm) D. Zimpfer and P. Spehar, 1996 was operated to assist capture and berth the satellite from the shuttle by the astronaut. NASA missions STS-61, STS-82, and STS-103 repaired the Hubble Japan demonstratedthe space manipulator to capture acooperative satellite whose attitu

11、de is stabilized during the demonstration viatele-operationfromthegroundcontrolstationKawano,I.,etal.1998,NoriyasuInaba,etal,2000.Allmentiabovespacerobotic technologies demonstrate the usefulness of space robot for space servicing. However their use is limited to capture the satellites that are coop

12、erative and attitude stabilized. For instance, the rotatedattwodeg/sec.NASAmissionThereforethecaptureandrecovery of a valuable uncontrolled satellite can be a class of future missionforthefuturespacerobot.Nearlyallofsatelliteservicingmissionsoccurredhavebeen executed by Extra-Vehicular Activity (EVA

13、) of the astronaut with the limited help of space robotic manipulator. It is very expensive and dangerous for the astronauts to capture an uncontrolled spinning satellite, even forslowlyspinning satellite. On the other hand, space robotic technologybecomesmoreandmore advancrecently. The space robot

14、carries out such satellite servicing mission automatically or with limited human support in the future. However, the first step of the capture is how to track and approach the target satellite. Stephen Jacobsen et al Jacobsen, S., et al. (2002) presented to plan a safekinematicstrajectory f or free

15、flying robots approaching an uncontrolled spinning satellite, they address how to let the space robot approach to the workspace of robotic manipulator in whichthemanipulatorcanoperate and capture the USS. Therefore,this paper assumes that the target satellite isintheworkspaceof space manipulator. it

16、 is desirable to contrive a new tracking and approach trajectory for space manipulator to capture the target satellite.So far, there are many studies on trajectory planning of space robot. S. Dubowsky and Kazuya Yoshida K.HashizumKyoshidandKHashizume (2001) utilized the ETS-VII as Yangsheng Xu Om P.

17、 Agrawal and Yangsheng Xu (1994) introduced a global optimum path planning forredundantspace manipulator. All examples mentioned interacHowever,onlyfewresearchers work on tracking trajectory planningofspacemanipulatorforcapturingthuncontrolledsatelliteinfact.HiroyukietalHiroyukiNagamatus,et al. (199

18、6) presented a capture strategy for retrieval of a tumbling satellite by a space robotic manipulator. Zhenghua Luo and Yoshiyuki sakawa Zhenghua Luo and Yoshiyuki Sakawa(1990)discussed the control law of capturing a tumbling object by a space manipulator. Therefore, how oplanfeasible tracking trajec

19、tory becomes ator based onspacebaseisdifferentwithterrestrialmanipulatorintrajectoryplanning and control.Hence it is necessary to plan the tracking trajectory of space manipulatorforapturing USS from the engineering point of view. This paper aims to address an innovative trackingrajectory planning m

20、ethod of space robot manipulator capturing the USS according .This paper is organized as follows. The section two describes the main problem and assumption,thesectionthree simplyreviewsthekinematicsanddynamicsquationofspacemanipulator.Then,weaddressthemotionestimation of USS in section four. The sec

21、tion five addresses ourtrajectoryplanningmethod.In section six, the computer simulation study and result are showed. The section seven summarizes the whole paper and educes the conclusion.2. Problem Formulation2.1. Description of ProblemOn-orbit capturing USS has not successful examples so far, as a

22、 typical example of on-orbit operation. Here, the authors mainly assume a capture operation in order to describe the problem. Fig.1 shows a schematic illustration of a tracking operation in which a space manipulator is tracking and approaching towards the target satellite. This operation can almost

23、been solved for terrestrial robotic manipulator. However, in space environment, it isvery difficult problem for robotic manipulator to capturUSS because of the dynamics couple and dynamic singularities which result in the big error of desired trajectory and real trajectory, this error possibly cause

24、s the catastrophic affair and demolish the space robot system completely. On the other hand, it is very important problem to plan a trajectory for space manipulator to track and approach the USS. This paper will focus on this problem. The key point of trajectory planning of robot is to solve inverse

25、 kinematics of space manipulator. The drawback in kinematics problems of free-flying space manipulator is that, as Longman et al R. W. Longman, R. E. LindBerg, and M. F. Zedd (1987) and Vafa et al Z. Vafa and S. Dubowsky (1987) haveaddressed them in their papers, the forward kinematics has notable d

26、ifficulty, i.e., the position and orientation of the manipulator end-effector do not have a closed form solution since they depend on the inertia property that changes according to the configuration of space manipulator. Therefore, the history of the postural change must be considered in order to de

27、rive the solution, all these problems make the inverse kinematics more difficult.In order to cope with tracking trajectory planning problem, the present paper describes a tracking trajectory according to the features of the USS and the space manipulator. As discussed in detail in section five.2.2. A

28、ssumptionIn this paper, the authors assume a model of space robot system which is composed of a space base and a robotic manipulator arm mounted on the space base. Fig.2 shows a simple model of space robot system with a single manipulator arm. In order to clarify the point at issue, they present the

29、 following assumption. a) The space robot system consists of n+1 links connected with n active joints, each joint has one rotational degree of freedom (DOF) and is controlled. The attitude or position of the space base can be controlled or not be controlled respectively. b) No mechanical restriction

30、 and external force or torque to the space manipulator system, i.e. the gravity isignored, so that the total momentum of the mechanical system is always conserved. The kinematics and dynamics analysis during the motion is in the inertial coordinate system. Therefore, the DOF of the space manipulator

31、 system in inertial coordinate is n+6, that is the attitude of the base has three DOFs, the position of the base has three DOFs, n represents the DOF number of the manipulator arm. c) For simplification, the whole system is composed of rigid bodies, thus, the space manipulator system is regarded a f

32、ree-flying mechanical chain consisted of n+1 rigid bodies d) The motion state of USS can be estimated by the sensors of the space robot system. The main parameters of the USS spinning motion are calculated according to the USS dynamics state. i.e. the spinning velocity can be estimated and the mark

33、points of USS motions the circle trajectory.Kinematics and Dynamics of Space Manipulator3.1 Kinematics of Space Robo The kinematics of robotic manipulator maps the relationship between Joint space and Cartesian space, the space-based kinematics is different form the terrestrial robot, the kinematics

34、 of ground robotic manipulator only depends on the joint variables, position and orientation of the end-effector respectively. However, the space-based kinematics also depends on the mass, inertia, position and orientation of the space base besides the joint variables because of the interaction betw

35、een the manipulator and space base. We will simply review it that has been described by Yoji Umetani et al Yoji Umetani and Kazuya Yoshida (1989). As shown in Fig.2, we define the vector relation of whole space robot model. The model assumed can be treated as a set of n+1 rigid bodies connected with

36、 n joints that form a tree configuration, each joint is numbered in series of 1 to n. We define two coordinate systems, one is the inertial coordinate system I in the orbit, the other is the base coordinate system 0 attached on the base body with its origin at the centroid of the base. The COM is th

37、e center of total system mass, all vectors in this paper are expressed in terms of coordinate I. We use three appropriate parameters such as Roll, Pitch, and Yaw to describe the attitude of base. Therefore, we use the vector principle to describe theDifferentiate the kinematics equation (1) with res

38、pect to time. Then, we can obtain the kinematics relationship in velocity level. The detail derivation sees the concerned articles Yoji Umetani and Kazuya Yoshida (1989).where: pe: The position vector of the end-effector in coordinate system I r0: The position vector of the centroid of the space bas

39、e body in I systeml0 : Vector pointing from the centroid of space base to the joint one. li : vector pointing from joint i to joint i+1 Jb: Jacobian matrix for the space base variables Jm: Jacobian matrix for the manipulatorxb: The position/orientation of the space base xe: The position/orientation

40、of the end-effector : : Joint variable of the manipulator3.2 Dynamics of Space Robot It is a general problem to derive the dynamics equation of space robotstem. Wutilize Roberson-Wittenburgs method Robert E. Roberson (1997) to derive the rigid dynamics of multi-body system. This method utilizes the

41、mathematical graph theory Jens Wittenburg (1997)escribe the interconnecting of the multi-body. The advantage of this method is that the various multi-body systems can be described by the uniform mathematical model. So far, there are many studies on the dynamics of space robot system. Therefore we wi

42、ll directly express the dynamic equation according to the assumed model. The motion equation of the space robot system is expressed in the following form Y. Xu and T. Kanade (1992).The symbols in the above equations are defined asfollowings:mi: The mass of link i of the space manipulator: The total

43、mass of the whole space robot systemri : The position vector of centroid of the link ipi : The position vector of joint iki: Unit vector indicating joint axis direction of the link i rg: The position vector of the total centroid of the space robot systemIi:Inetia tenor of the link i with respect to

44、its masscentercb: Velocity dependent non-linear term for these cm: Velocitydependentnon-linearterm for he manipulator armFb: The External force and torque on the space base Fh: The external force and torque on the end-effector : The joint torque of the manipulator armHb: The inertial matrix of the s

45、pace baseHm: The inertial matrix for the manipulatorHbm: The coupling inertial matrix between the space base and manipulatorAll vectors are described with respect to the inertial coordinate systemI, cb and cm can be obtained by inverse dynamic. The inverse dynamic computation is useful for a compute

46、d torque control. Here, the authors use n-order recursive Newton-Euler approach J. S. Y.Luh, M. W. Walker and R. P. C.Paul (1980) K. Yoshida (1997) to compute inverse dynamics. In addition, calculating inverse dynamics can obtain the reaction force/moment on the space base.where: Fi, Ni are inertial

47、 force and moment exterting onthe centroid of link i. Otherwise we define force andmoment fi, ni exterting on the joint, fci and nci exterting onthe end-effector. Thus, the dynamic equilibriumexpressed as following form for a revolution joint:From the equation (17), we can obtain every joint torquea

48、s following: Moreover, the reaction force and moment on the spacebase can be obtained as following equations:The equation (19) can be used to measure the interactionbetween the space base and space manipulator. These parameters are very important reference for designing the attitude control system a

49、nd orbit control system. Moreover, the coordinate control of space base and space manipulator needs these parameters.The symbols in equation (17), (18) and (19) are defined as followings: sij: the elementofIncidencematrixs,thedetaileddefinitioseesmathematicalgraphtheory. sei: the element of Incidenc

50、e matrix sej (j = 1,n), that represents a j is -link. lij:vector from joint i to joint j, from Fig.2, we know lij =cij-cii. cij : vector from the centroid of link i to joint j.For whole space robot system, the external force or torque on the space base Fb, which can be generated by jet thrusters or

51、reaction wheels, and Fe can be assumed zero before the end-effector contacts the objective. Therefore the linear and angular momenta of whole system are conservative when Fh= 0. The motion of system isgoverned by only inertial force/torque on the manipulator joint . Thus, we can obtain the following

52、 momenta equation from equation (3)At the beginning, assume0 for simplification, thus,from equation (20), we obtain, the matrix Jg is calledGeneralized Jacobian Matrix (GJM) or Space JacobianMatrix (SJG). GJM is used to calculate the joint angularvelocity and end-effector velocity. Moreover, it is a

53、lsoused to check whether the space manipulator systemcauses the dynamics singularities. When the determinantof GJM is equal to zero or the GJM loses full rank, themanipulator appears the dynamics singularities. Inaddition, the GJM can be used to design controller usually.All mentioned above is the f

54、undamental knowledgeabout space robot system. The following trackingtrajectory planning and control is base on this dynamicMotion Estimation of USSIn this section, we describe to estimate the motion state and equation of USS. The USS to be rescued has unique characteristics as follows: the orbital i

55、nformation such as altitude and inclination of the USS will be known by the ground control station. The size, shape and mass property of the USS are also well known in advance from design phase information. The handle location will be identified by human decision. Therefore we also assume that the U

56、SS is equipped with visual marker, signal reflectors, GPS, and so on for simplification.Here, we assume that the USS is nearly axis-symmetric shape with a grapple handle on the maximum momentum axis in order to simplify the complicated problem. Moreover, there are some mark points on the USS so that

57、 the CCD cameras equipped in manipulator end-effector can measure the position, orientation and estimate its spinning velocity. Hence, the grapple handle is the key point of tracking trajectory of space manipulator. Therefore, the mission of CCD cameras is to measure the position and orientation fro

58、m manipulator end-effector coordinate E to the coordinate frame O attached to the USS. Define XUSS = PUSS, VUSS, USS, USS,T as a state vector to denote the kinematics parameters. So the motion equation of USS is given as following formsThe symbols in the above equation are defined as followings:f (.

59、): Denotes a non-linear function which describe USSmotionW: Denotes white Gaussian system noise vector. PUSS: PUSS = x, y, z be the position of the center of USS massVUSS : VUSS = x, y, z be the velocity of the center of USS massUSS: USS =1, 2, 3 be the orientation angles fromcoordinate frame O to E

60、.USS: USS = x, x, x be the angular velocity of USS. A 12th-order extended Kalman filter (EKF) HiroyukiNagamatus, et al. (1996) is used to estimate the position,orientation and spinning angular velocity of USS incoordinate frame E. Now, the desired position andangular velocity of manipulator hand are