vibration suppression of fixed-time jib crane maneuvers

1、Vibration suppression of fixed-time jib crane maneuvers Gordon G. Parker, Ben Petterson, Clark R. Dohrmann, Rush D. Robinett Sandia National Laboratories P.O. Box 5800 Mail Stop 0439 Albuquerque, NM 87185-0439 ABSTRA

2、CT A jib crane consists of a pendulum-like end line attached to a rotatable jib. Within this general category of cranes there exist devices with multiple degrees of freedom including variable load-line length and varia

3、ble jib length. These cranes are commonly used for construction and transportation applications. Point-to-point payload maneuvers using jib cranes are performed so as not to excite the spherical pendulum modes of th

4、eir cable and payload assemblies. Typically, these pendulum modes, although time-varying, exhibit low frequencies. The resulting maneuvers are therefore performed slowly, contributing to high construction and tran

5、sportation costs. The crane considered here consists of a spherical pendulum attached to a rigid jib. The other end of the jib is attached to a direct drive motor for generating rotational motion. A general app

6、roach is presented for determining the open-loop trajectories for the jib iotation for accomplishing fixed-time, point-to-point, residual oscillation free, symmetric maneuvers. These residual oscillation free tr

7、ajectories purposely excite the pendulum modes in such a way that at the end of the maneuver the oscillatory degrees of freedom are quiescent. Simulation results are presented with experimental verification. Keywords

8、: Rotary Crane, Control, Swing-Free, Oscillation-Free, Input Shaping 1 .INTRODUCTION Construction and transportation cranes can generally be grouped into one of two categories based on their configuration. The first

9、category consists of overhead, gantry cranes. These systems incorporate a trolley which translates in the horizontal plane. Attached to the trolley is a load-line for payload attachment. Typically, they have varying lo

10、ad-line length capabilities. The second category consists of rotary cranes. As the name implies, the load-line attachment point undergoes rotation. Other degrees of freedom may exist such as translation of the load-

11、line attzchment point along the jib, variable load-line length, or if the jib is replaced by a boom, the chiuacteristk boom rotational motion, known as luffing*. - -. Auernig and Troger consider time optimal payload

12、 maneuvers of a gantry crane undergoing trolley translation and load-line length change. The coupled, nonlinear equations of motion and adjoint equations, obtained from the application of Pontryagin's maximum

13、principle, are solved analytically for the cases of constant and variable hoisting speeds. In both cases the maneuvers are developed such that the payload is residual oscillation free. Moustafa and Ebeid demonstrat

14、e a state feedback controller for damping load sway for a gantry crane configured to move along two orthogonal directions in the horizontal plane. This work is expanded on by Ebeid et. al. to incorporate actuator

15、 dynamics into the crane model. Fliess et. al. investigate a feedback linearizing controller for a onedimensional gantry crane. Trolley traversal and load-line length changes are considered. Simulation results indicat

16、e the ability of the closed-loop controller to control load sway for relatively slow maneuvers. This same system is examined by Nguyen where simulation and experimental results of a nonlinear st2te-feedback controller

17、is used. Small motions are assumed about a specified operating point. This allows for decoupled equations of motion and decoupled controller design. Sakawa and Nakazumi investigate a rotary crane undergoing hub and bo

18、om rotation and load hoisting using a combined open and closed-loop approach. The open-loop input to the crane is designed based on a postulated set of functions such that the sway motion of the load is excited minim

19、ally. The closed-loop controller is then switched on when the maneuver is near the end, providing significant sway damping. Vaha et. al. generate suboptimal, minimum time inputs for a rotary crane. Tracking is achieve

20、d via a state feedback control law. However, radial sway, due to centripetal acceleration of the payload, is not compensated. Souissi and Koivo consider a rotary crane undergoing a boom-rotation-boom maneuver using a pr

21、oportional- *Boom rotational motion, referred to as luffing, causes the tip of the boom to move vertically. DlSTRl6UTlON OF THIS DQCUMENT I SUNUMITED 6 2 %STE integral-derivative controller similar to Fliess etal. 4.

22、 The simulation model considers both radial and tangential payload sway, however, the control strategy used results in residual load oscillation. In this paper a procedure for generating open-loop inputs for a rotary ji

23、b crane is introduced. The primary maneuver of interest is the residual oscillation, point-to-point movement of a payload. The input angular acceleration to the jib motor is postulated as having a pulsecoast-pulse form

24、. A numerical optimization technique is used to generate the parameters which define this pulse sequence such that the maneuver is residual oscillation f r e e .Of secondary interest are maneuvers where the payload osc

25、illates in a specified manner at the end of the maneuver. Again, the pulse sequences are designed via numerical optimization. Experimental results for these maneuvers verify the results of the numerical optimization pr

26、ocedure. 2. CRANE DESCRIPTION The crane considered here consists of a rotatable jib with a load-line attached to the end. A mass, representing a payload, is attached to the end of the load-line. This apparatus is shown

27、 in Fig. 1 The ii,, i i , ,ii3 coordinate system is attached to the jib and rotates about the hub with angular rate y . The rotation angles el., 8 ,are defined as rotations of the load-line about the 8,, 6, axes resp

28、ectively. The attachment point of the load-line to the jib is at a distance x from the center of rotation of the hub. The load-line has length L and the payload has mass m . The two rotations will from now on be ref

29、erred to as the radial (0,) and the tangential (e1 ). The input to this system is the hub rotation trajectory y ( t ) and the outputs are the rotation angles of the load-line, 0, (t) ,e, ( t ) . The experimental s