Method for controlling the movement of an articulated hose carrier of a suction excavator

Abstract

A method for controlling the movement of an articulated hose mount having at least n>2 members, wherein a change in angle can be induced between neighboring members with the help of a respective drive includes: a) determining the starting position of the n members with the help of sensors; b) input of a direction vector and a velocity parameter; c) determining a target position, which should be taken by a suction crown, on the free end of the last member; d) determining n angle changes which must be carried out on the n members in order to reach the target position while maintaining the following condition: d.i. the suction crown moves into the target position along a straight path of movement;
e) controlling the drives associated with the n members in order to perform the predetermined angle change on the n members; and
f) cyclically repeating the aforementioned method steps until the direction vector and/or the velocity parameter are zero.

Claims

1. A method for controlling the movement of an articulated hose mount, which carries the suction hose of a suction dredge, wherein the articulated hose mount has at least n>2 members and a change in angle can be induced between neighboring members with the help of a respective drive, wherein the following steps are carried out: a) determining the starting position of the n members with the help of sensors; b) input of a direction vector and a velocity parameter; c) determining a target position, which should be assumed by a suction crown on the free end of the last member; d) determining n angle changes which must be carried out on the n members in order to reach the target position while maintaining the following conditions: d.i. the suction crown moves into the target position along a straight path of movement; d.ii. the sum of all angle changes on then members is minimal; e) controlling the drives associated with the n members in order to perform the predetermined angle change on the n members; f) cyclically repeating the aforementioned method steps until the direction vector and/or the velocity parameter are zero.

2. The method according to claim 1, wherein n angular velocities are additionally determined in step d) with which the angle changes are carried out in step e).

3. The method according to claim 1, wherein the direction vector to be input and preferably also the velocity parameters are determined by an operator from the deflection of at least one operating level carried out.

4. The method according to claim 1, wherein limit values, which are maintained in determining the angle change and/or the angular velocity can be preselected for at least one of the n members.

5. The method according to claim 1, wherein the angle changes are determined by using the movement equations of an inverse kinematics of the articulated hose mount taking into account the angular position of each one of the n members recorded by the sensors.

6. The method according to claim 1, wherein the angle changes are determined by access to a table of values in which all the ideal positions of all the n members are stored for all possible target positions, wherein the target position closest to the current position is approached along the direction vector.

7. The method according to claim 1, wherein the direction vector is made up of two one-dimensional subvectors, and the target position lies in a vertically spanned X-Y plane.

8. The method according to claim 7, wherein a rotational angle is input which defines the desired angular position of the vertically spanned X-Y plane about a rotational axis of the articulated hose mount, and in that the articulated hose mount is moved into this angular position by a pivot drive.

9. A suction dredge comprising: a vehicle frame; a material collecting container; a suction fan; an articulated hose mount which has a suction hose with a receiving opening on a suction crown and has at least n>2 members between which a change in angle can be induced with the help of a respective drive; a control unit for controlling the movement of the articulated hose mount; characterized in that the control unit is configured to carry out a method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Additional details, advantages and refinements of the present invention are derived from the following description of a preferred embodiment with reference to the drawings, in which:

(2) FIG. 1 shows a simplified sectional view of a suction dredge from the side;

(3) FIG. 2 shows the suction dredge in a view from the rear with an articulated hose mount that is arranged on the rear end of the suction dredge and has been retracted for transport;

(4) FIG. 3 shows the suction dredge and in a perspective view with the articulated hose mount fully extended;

(5) FIG. 4 shows the articulated hose mount extended on the suction dredge in a view from the rear;

(6) FIG. 5 shows a schematic diagram of the articulated hose mount;

(7) FIG. 6 shows a block schematic of a control system for carrying out the method according to the invention.

DETAILED DESCRIPTION

(8) FIG. 1 shows a simplified, partially sectional side view of a suction dredge 01, comprising first a vehicle frame 02 and a plurality of vehicle wheels 03 in a traditional manner. In addition, the suction dredge comprises a material collecting container 05 which is mounted on the vehicle frame 02 and/or an auxiliary frame. A suction connection 06 with a suction hose 20 connected to it is provided on the rear end of the material collecting container 05. A suction connection (not shown), by means of which material is sucked in, can be mounted on the free end of the suction hose 20, with the help of a suction stream 21, as symbolized by flow arrows.

(9) In the embodiment illustrated in FIG. 1, the suction stream 21 runs first in the upper region of the material collecting container 05 in an upper air duct 27 up to a baffle 22, where it is deflected into a collecting chamber 23. Based on the increased volume, the velocity of flow is reduced in the collecting chamber 23, so that material 24 is deposited in the collecting chamber. This suction flow then runs into a filter unit 25, where smaller particles, which are still present in the suction stream, are filtered out. In the embodiment shown here, the collecting chamber 23 is in front of the filter unit 25 in the direction of travel. The suction dredge 01 also carries a suction fan 26, which creates the air stream to form the suction stream 21 and is positioned upstream from the material collecting container 05 in the direction of travel.

(10) FIG. 2 shows a rear view of the suction dredge 01, which carries an articulated hose mount 40 in the retracted condition on its rear end. The suction hose, which is usually attached to the articulated hose mount 40, however, and is moved by it in order to be brought into the desired working position, is not visible in this view. In particular, the articulated hose mount 40 must be brought into this transport position on the suction dredge for the purpose of transport. In the embodiment illustrated here, a plurality of members 45 of the hose mount stands at a 90° angle to one another. The angle between the last two members is greater than 90°, so that the last member can be suspended from a retraining hook 44.

(11) The articulated hose mount is mounted rotatably on a console 41, which is connected to the vehicle frame 02. A pivot drive 42 makes it possible for the entire articulated hose mount 40 to be pivoted approx. 180° about a Y axis when the articulated hose mount has been extended. The pivot drive 42 preferably comprises a rotating ball connection with an integrated worm gear.

(12) FIG. 3 shows a perspective view of the suction dredge 01 with the articulated hose mount 40 fully extended. For operation, the articulated hose mount 40 must first be brought out of the transport position (FIG. 2) and into a working position. Since this movement would require a great deal of manual dexterity on the part of the operator, and a mistake in operation could cause relatively major damage, this extension movement is preferably automated. The required angle changes in the individual members and their chronological order into the defined starting position are fixedly predetermined.

(13) At the free end of the suction hose 20, there is a suction crown 43, on which a suction connection (not shown) can be mounted as needed to lengthen it in the negative Y direction. For controlling the movement of the articulated hose mount, as described in detail below, the midpoint in the cross section of the suction crown 43 preferably forms the reference point for the position of the free end of the suction hose and/or the suction connection attached to it in a straight line. FIG. 3 also shows movement arrows illustrating the possible movements at this reference point. Straight-line movements in X and Y directions are possible, and pivoting about a rotational angle γ by activation of the pivot drive 42 is also possible. This describes a cylindrical coordinate system.

(14) FIG. 4 shows a simplified view of suction dredge 01 from the rear with the articulated hose mount 40 completely extended. In the example shown here, the articulated hose mount comprises six mount sections or members 45a-45f. There is one joint 46a-46e between each member 45. The angular position of the neighboring members relative to one another can be altered by the respective drives, namely hydraulic cylinders 47a-47e in the example shown here. In FIG. 4, for example, the members adjacent to the joints 46c and 46d have assumed an angular position of 180° relative to one another with the hydraulic cylinders 47c, 47d in the fully extended position. The same members have an angular position of 90° to one another in FIG. 2.

(15) A system for determining the position is arranged on each member 45. In a preferred variant, inclination sensors 48 are used for this purpose. It is also possible to use angle sensors at the articulation points. According to the invention, the articulated hose mount 40 is controlled with the aid of a controller, which carries out the method according to the invention.

(16) Each sensor 48, which may also be placed in another location on the respective member, enables a determination of the inclination as well as preferably also the angular velocity (rotational rate) of the respective member 45. So-called inclination transmitters have proven to be especially suitable for detection of measured values in this regard. These inclination transmitters are used for accurate, rapid detection of prevailing inclinations and/or inclination angles of the members in two axes X, Y that remain stable over the long run. The inclination transmitters as sensors 48 are based on a multi-sensor system, which detects the measured values of six degrees of freedom. Then the measured data thereby detected is digitized and made available over a so-called CANopen protocol to a CAN field bus system for further processing by an electronic evaluation system. Detection of measured inclination values by the respective sensor 48 then takes place by detection of acceleration values in three axes, based on the gravitational field, and the angular velocities for the individual members are detected in three axes by means of a so-called gyroscope.

(17) The last member 45f, on which the suction connection is mounted, is always oriented parallel to the Y axis in order to achieve optimum working results. Then the directions of movement in extension and/or retraction in the X direction and movement up and down in the Y direction can be controlled linearly by remote control. A maximum of two joysticks on the remote control are then needed for this. Pivoting can be controlled separately.

(18) The method, which can preferably take place by execution of a data processing program, then determines the output position of the n=6 members cyclically from the position signals of the individual members 45 supplied by the sensors 48. Thus, the position of the reference point 43 (suction crown) on the free end of the last member 45f is also known as the current position. Next, a direction vector and a velocity parameter are input, preferably from motion commands, which are input by the operator on an operating unit by using one or two joysticks. Then the required control commands for the individual hydraulic cylinders can be determined from the direction vector and the velocity parameters in order to adjust the required angle changes on the n joints.

(19) Determination of the angle changes is described below as an example. To this end, reference is made to FIGS. 5 and 6. FIG. 5 shows the articulated hose mount in a highly simplified form in the cylindrical coordinate system used here, while FIG. 6 shows essential linkages and system elements of a control system that can be used.

(20) First, the inverse kinematics of the articulated hose mount shall be considered. For the embodiment considered here, the general system requirements are defined as follows: the articulated hose mount has n>2 members; respective hydraulic cylinders are present as drives between neighboring members in order to change the angular positions of the members relative to one another; each member has a position sensor, preferably an inclination sensor; each inclination sensor outputs the absolute angle, based on the horizon, and forwards this over a CAN bus to a central control unit, for example; each inclination sensor additionally outputs over the CAN bus the angular velocity at which the angle change is carried out; the central control unit takes over the generation of target values by means of inverse kinematics as well as the regulation of the individual hydraulic cylinders.

(21) With reference to the coordinates shown in FIG. 5, as can be seen on the articulated hose mount having n>2 members, the position P of the reference point on the suction crown 43 can be calculated as follows:

(22) $\begin{array}{cc}X=l_1\sin \left({\varphi }_1\right)+l_2\sin \left({\varphi }_1+{\varphi }_2\right)+\mathrm{.Math.}+l_n\sin \left({\varphi }_1+\mathrm{.Math.}+{\varphi }_n\right)=\underset{i=1}{\overset{n}{.Math.}}\left(l_i\sin \left(\underset{j=1}{\overset{i}{.Math.}}{\varphi }_j\right)\right)& \left(1\right)\\ Y=l_1\cos \left({\varphi }_1\right)+l_2\cos \left({\varphi }_1+{\varphi }_2\right)+\mathrm{.Math.}+l_n\cos \left({\varphi }_1+\mathrm{.Math.}+{\varphi }_n\right)=\underset{i=1}{\overset{n}{.Math.}}\left(l_i\cos \left(\underset{j=1}{\overset{i}{.Math.}}{\varphi }_j\right)\right)& \end{array}$

(23) In this mathematical equation, I.sub.1 corresponds to the first member 45a, I.sub.2 corresponds to the second member 45b, etc. The first member I.sub.1 can be pivoted at its lower end within the coordinate system X, Y by means of the pivot drive 42.

(24) The goal of the control system in the method according to the invention is to maintain the angles ϕ.sub.1 . . . ϕ.sub.n by stipulation of X and Y, so that the articulated hose mount executes a steady movement. There cannot be an analytical solution of equation (1) here because only two equations are available for determining n unknowns. To solve this problem, each joint 46 is regarded as a spring with the stiffness s.sub.1, . . . , s.sub.n and is held in the positions ϕ.sub.1,0, . . . , ϕ.sub.n,0. The movement of P is implemented by the forces F.sub.x and F.sub.y acting on P. Disregarding friction and the weight of the elements, this yields the movement equations:

(25) $\begin{array}{cc}{J}_1{\stackrel{\mathrm{.Math.}}{\varphi }}_1=\left({\varphi }_{1,0}-{\varphi }_1\right)s_1+\left(F_x\cos \left({\varphi }_1\right)-F_y\sin \left({\varphi }_1\right)\right)l_1& \left(2\right)\\ J_2{\stackrel{\mathrm{.Math.}}{\varphi }}_2=\left({\varphi }_{2,0}-{\varphi }_2\right)s_2+\left(F_x\cos \left({\varphi }_1+{\varphi }_2\right)-F_y\sin \left({\varphi }_1+{\varphi }_2\right)\right)l_2& \\ \mathrm{.Math.}& \\ J_n{\stackrel{\mathrm{.Math.}}{\varphi }}_n=\left({\varphi }_{n,0}-{\varphi }_n\right)s_n+\left(F_x\cos \left(\underset{j=1}{\overset{n}{.Math.}}{\varphi }_j\right)-F_y\sin \left(\underset{j=1}{\overset{n}{.Math.}}{\varphi }_j\right)\right)l_n& \end{array}$

(26) In a steady state, these equations hold:

(27) $\begin{array}{cc}0=\left({\varphi }_{1,0}-{\varphi }_1\right)s_1+\left(F_x\cos \left({\varphi }_1\right)-F_y\sin \left({\varphi }_1\right)\right)l_1& \left(3\right)\\ 0=\left({\varphi }_{2,0}-{\varphi }_2\right)s_2+\left(F_x\cos \left({\varphi }_1+{\varphi }_2\right)-F_y\sin \left({\varphi }_1+{\varphi }_2\right)\right)l_2& \\ \mathrm{.Math.}& \\ 0=\left({\varphi }_{n,0}-{\varphi }_n\right)s_n+\left(F_x\cos \left(\underset{j=1}{\overset{n}{.Math.}}{\varphi }_j\right)-F_y\sin \left(\underset{j=1}{\overset{n}{.Math.}}{\varphi }_j\right)\right)l_n& \end{array}$

(28) Together with the equations in (1) above, this yields an equation system with n+2 equations and n+2 unknowns ϕ.sub.1 . . . ϕ.sub.n, F.sub.x and F.sub.y. To reduce the system to the order n, the last two equations (3) must be solved for F.sub.x and F.sub.y. To this end, they are converted to the form:
0=a.sub.1+F.sub.xa.sub.2−F.sub.ya.sub.3
0=b.sub.1+F.sub.xb.sub.2−F.sub.yb.sub.3  (4)
where

(29) $\begin{array}{cc}{a}_1=\left({\varphi }_{n-1,0}-{\varphi }_{n-1}\right)s_{n-1},a_2=\cos \left(\underset{j=1}{\overset{n-1}{.Math.}}{\varphi }_j\right)l_{n-1},a_3=\sin \left(\underset{j=1}{\overset{n-1}{.Math.}}{\varphi }_j\right)l_{n-1}& \left(5\right)\\ b_1=\left({\varphi }_{n,0}-{\varphi }_n\right)s_n,b_2=\cos \left(\underset{j=1}{\overset{n}{.Math.}}{\varphi }_j\right)l_n,b_3=\sin \left(\underset{j=1}{\overset{n}{.Math.}}{\varphi }_j\right)l_n& \end{array}$

(30) The forces are then obtained as:

(31) $\begin{array}{cc}{F}_x=\frac{b_1{a}_3-b_3{a}_1}{a_2{b}_3-b_2{a}_3}& \left(6\right)\\ F_y=\frac{b_1{a}_2-b_2{a}_1}{a_2{b}_3-b_2{a}_3}& \end{array}$

(32) The divisions may be carried out at any time because resubstitution and applying the addition theorems yields the following for the denominator:

(33) $\begin{array}{cc}{a}_2{b}_3-b_2{a}_3=\cos \left(\underset{j=1}{\overset{n-1}{.Math.}}{\varphi }_j\right)l_{n-1}\sin \left(\underset{j=1}{\overset{n}{.Math.}}{\varphi }_j\right)l_n-\cos \left(\underset{j=1}{\overset{n}{.Math.}}{\varphi }_j\right)l_n\sin \left(\underset{j=1}{\overset{n-1}{.Math.}}{\varphi }_j\right)l_{n-1}=l_{n-1}{l}_n\left(\cos \left(\underset{j=1}{\overset{n-1}{.Math.}}{\varphi }_j\right)\sin \left(\underset{j=1}{\overset{n}{.Math.}}{\varphi }_j\right)-\cos \left(\underset{j=1}{\overset{n}{.Math.}}{\varphi }_j\right)\sin \left(\underset{j=1}{\overset{n-1}{.Math.}}{\varphi }_j\right)\right)=l_{n-1}{l}_n\sin \left({\varphi }_n\right)& \left(7\right)\end{array}$

(34) Since ϕ.sub.n≠0 holds due to the angular limitation of the articulated hose mount, the denominator is different from zero.

(35) The equation system is now as follows:

(36) $\begin{array}{cc}0=f\left(x\right)=\left[\begin{array}{c}\underset{i=1}{\overset{n}{.Math.}}\left(l_i\sin \left(\underset{j=1}{\overset{i}{.Math.}}{\varphi }_j\right)\right)-X\\ \underset{i=1}{\overset{n}{.Math.}}\left(l_i\cos \left(\underset{j=1}{\overset{i}{.Math.}}{\varphi }_j\right)\right)-Y\\ \left({\varphi }_{1,0}-{\varphi }_1\right)s_1+\left(F_x\cos \left({\varphi }_1\right)-F_y\sin \left({\varphi }_1\right)\right)l_1\\ \mathrm{.Math.}\\ \left({\varphi }_{n-2,0}-{\varphi }_{n-2}\right)s_{n-2}+\left(F_x\cos \left(\underset{j=1}{\overset{n-2}{.Math.}}{\varphi }_j\right)-F_y\sin \left(\underset{j=1}{\overset{n-2}{.Math.}}{\varphi }_j\right)\right)l_{n-2}\end{array}\right]& \left(8\right)\end{array}$

(37) where F.sub.x and F.sub.y are obtained from (6) and x=[ϕ.sub.1 . . . ϕ.sub.n].sup.T.

(38) This equation system cannot be solved analytically, which is why a Newtonian method (or some other adequate method) should be used to solve it. To this end, the function ƒ(x+Δ) in the equation is replaced by a Taylor series expansion of the first order:

(39) $\begin{array}{cc}0=f\left(x_{k+1}\right)=f\left(x_k\right)+\frac{\partial f}{\partial x}{|}_{x_k}\underset{\underset{=\Delta }{︸}}{\left(x_{k+1}-x_k\right)}& \left(9\right)\end{array}$
yielding the iteration:

(40) $\begin{array}{cc}\Delta =-{\underset{\underset{=J}{︸}}{\left(\frac{\partial f}{\partial x}{.Math.}_{x_k}\right)}}^{-1}f\left(x_k\right)& \left(10\right)\\ x_{k+1}=x_k+\Delta & \end{array}$
with the Jacobi matrix J of f. Instead of calculating the inverse of the Jacob matrix, the equation system:
JΔ=−ƒ  (11)
is solved for Δ with the help of a Gaussian elimination (or some other adequate method).

(41) To precontrol the angular velocity in the individual elements, it is possible to calculate as follows by deriving equation (8) according to time:

(42) 0$\begin{array}{cc}0=\frac{\partial f}{\partial x}\frac{\mathrm{dx}}{\mathrm{dt}}=J\stackrel{.}{x}-\left[\begin{array}{c}\stackrel{.}{X}\\ \stackrel{.}{Y}\\ 0\\ \mathrm{.Math.}\\ 0\end{array}\right]& \left(12\right)\end{array}$
And then by solving the linear equation system for {dot over (x)}:

(43) $\begin{array}{cc}\left[\begin{array}{c}\stackrel{.}{X}\\ \stackrel{.}{Y}\\ 0\\ \mathrm{.Math.}\\ 0\end{array}\right]=J\stackrel{.}{x}& \left(13\right)\end{array}$
the angle changes {dot over (x)}=[{dot over (ϕ)}.sub.1 . . . {dot over (ϕ)}.sub.n].sup.T.sup.T can be calculated from the change in the positions {dot over (X)} and {dot over (Y)} over time.

(44) It should be pointed out that the mathematical methods presented above show only one option for carrying out the steps of the method according to the invention. Those skilled in the art will recognize that modified methods can also be used.

(45) To carry out the method described here, a regulator like that shown in principle in FIG. 6 may be used. The input variables for the controlled system are as follows: The ideal angular velocity for each segment (from the inverse kinematics described above) Ideal angle for each segment (from the inverse kinematics described above) The actual angular velocity of each member (measured variable from the sensor) Actual angle of each segment (measured variable from the sensor).

(46) Those skilled in the art will recognize that the regulator can be adapted, for example, if certain limit values are also to be taken into account, as already described above.

(47) Each member 45 preferably has its own regulator which sets the hydraulic cylinder 45 (drive) on the basis of actual variable and target variables, so that the ideal angle and the ideal angular velocity are set on the member.

(48) The articulated hose mount 40 is preferably always aligned in the optimal static kinematic position. Since the movement of the reference point 43 should be as linear as possible, a complex superpositioning of the movements of the individual members of the articulated hose mount is necessary. A downstream position regulation can preferably permanently smooth the movements initiated by the controller. In addition, blocked regions, in which the range of movement may be restricted, can also be defined. This relates, for example, to the area in which the vehicle is located in order to prevent collisions of the articulated hose mount with other vehicle parts.

LIST OF REFERENCE NUMERALS

(49) 01 Suction dredge 02 Vehicle frame 03 Vehicle wheels 05 Material collecting container 06 Suction connection 20 Suction hose 21 Suction stream 22 Baffle 23 Collecting chamber 24 Deposited material 25 Filter unit 26 Suction fan 27 Upper air duct 40 Articulated hose mount 41 Console 42 Pivot drive 43 Suction crown/reference point 44 Retaining hook 45 Members of the articulated hose mount 46 Joints 47 Drives/hydraulic cylinders 48 Sensors