GB1605103A

GB1605103A - Apparatus for the positioning and position-stabilisation of an inert mass supported on a base

Info

Publication number: GB1605103A
Application number: GB6545/73A
Authority: GB
Original assignee: PIETSCH L
Current assignee: PIETSCH L
Priority date: 1972-04-13
Filing date: 1973-02-09
Publication date: 1981-12-16
Also published as: FR2489013A1; DE2217684C1; FR2489013B1

Description

(54) APPARATUS FOR THE POSITIONING AND POSITION-STABILISATION OF AN INERT MASS SUPPORTED ON A BASE (71) I, LUDWIG PIETZSCH, of D-75 Karlsruhe, Richard Wagner Strasse 5, Germany a citizen of the Federal Republic of Germany, do hereby declare the invention, for which I pray that a patent may be granted to me, and the method by which it is to be performed, to be particularly described in and by the following statement:- The invention relates to apparatus means for the positioning and stabilisation of position of an inert mass supported on a base and movable with at least one degree of freedom, including a control device which produces one or more manipulating variables, the number of which depends upon the number of degrees of freedom.

Apparatus of this kind, for example, may be used to stabilise and align a tubular weapon on a stationary or moving target, said weapon being supported at its centre of gravity on a full-track vehicle. The base is in that case the hull of the full-track vehicle and the inert mass the tubular weapon.

Apparatus of this kind is known in which, in order to compensate deviations from the desired direction via a directional drive, torques are applied to the tubular weapon.

The reaction torque of the directional drive is directly supported upon the hull. This causes perturbed motions of the hull immediately over the directional drive to be transmitted to the tubular weapon, and these have to be compensated. Such perturbed motions, for example, are the pitching motions of the hull when the fulltrack vehicle is moving over uneven surfaces.

The problem upon which the present invention is based is to provide apparatus of the type mentioned herein, with which rapid and precise positioning and positionstabilisation of the mass is possible, irrespective of the perturbed motions of the base. In order to solve this problem, in the apparatus of the present invention there is provided means by which each manipulating variable produced by the control device is respectively transformed into a force which presses at least one first part arranged on the mass against at least one second part arranged on the base whilst the second part is moving relatively to the first part, whereby a positioning or positionstabilising frictional force or torque acting on the mass is created by the relative sliding movement between the said two parts.

Since the frictional values, in the case of the functioning friction-pairings, are independent of the speed of the relative sliding movement between the two parts, it is possible with the apparatus according to the invention, by regulating the pressure force, to generate from the or each manipulating variable definite forces or torques which accelerate the mass, independently of movements of the base, towards the desired position and brake it when it reaches that position.

The traverse speed of the second part should preferably not be less than the corresponding traverse speed, for example of the pitching motion, of the base.

It is appropriate for the second part to be a rotating disc and the first part a friction pad adapted to be pressed against the disc; for example the disc is supported on the base and can be continuously driven, while the friction pad is mounted at the mass.

In a preferred embodiment of the invention, a pair of contra-rotating discs constituting two of the said second parts is provided for each degree of freedom, a pair of friction pads provided as two of the said first parts being assigned respectively to the discs of the pair, which friction pads can be actuated separately from one another according to the direction in which the mass is to be reset.

The invention may be carried into practice in various ways, but certain specific embodiments will now be described by way of example only and with reference to the accompanying schematic drawings, in which: Figure 1 shows a diagram of an apparatus embodying the invention, and Figure 2 shows a control diagram with the control device of Figure 1 shown in detail.

In Figure 1 a tubular weapon 1 is designated by the referepce numeral 1, said weapon being pivoted at the angle c via bearings 2 and 3 to the hull (not shown) of a full-track vehicle. Each bearing has two concentric bearing boxes, one of which is continuously driven oppositely to the driven bearing box of the other bearing. This ensures that when the weapon 1 swivels, only the hydrodynamic bearing friction has to be overcome, which is less than the limitor mixed-friction in the starting area and is to a great extent independent of the speed of rotation. A caliper 5 is firmly connected with the rocking shaft 4 of the tubular weapon 1. The caliper 5 has in each leg a cylinder 6, 7 with a piston 8, 9 supported therein, and each of these can actuate a friction pad 10, 11.The friction pads 10, 11 act upon brake-discs 12, 13, which are pivoted on the hull (not shown) at 14, 15.

The brakediscs 12, 13 are continuously driven in contra-rotation via a bevel gearing (designated totally by the reference 16) by a drive designated totally by the refeience 17, such as an hydraulic drive.

The friction pads 10, 11 are arranged to be actuated for the application of definite directional torques to the rocking shaft 4 of the tubular weapon 1 by compressive thrusts of their pistons 8, 9 produced by the application of hydraulic pressures Pl, P2.

This actuation depends upon the deviation from a set alignment of the tubular weapon 1, and is effected by means of the control device indicated in Figure 1 by the box 20 and represented in detail in Figure 2. The set value of said alignment is, for example, preset by an optical target pick-up device 21, which sets a directional angle P ,. This directional angle ,e, is compared with the instantaneous directional angle qw a (measured on the control section) of the tubular weapon 1 and from this the deviation signal Ap is formed and supplied to the control device 20. Referring to Figure 2, differentiated signals Ap and +2 are formed in a module 22 of the control device 20.The quantities cp, A and ç2 are combined in a summation unit 23 in accordance with a given function to form the torque set value M,. This set torque is an input quantity for a module 24, which receives as second input quantity the torue M measured in the control circuit after the final control element 25. From M, and M the manipulating variable i is formed, which is fed to the final control element 25.

The final control element 25 comprises a valve arrangement which is controlled by the manipulating variable i and which according to the direction of swing of the resetting rotation to be imposed on the tubular weapon 1 supplies hydraulic pressure medium to act upon the piston 8 or 9 of the friction pad 10 or 11, the medium being fed from a pump via an adjustable flow valve of the element 25 to the respective piston chamber in the selected cylinder 6 or 7 and being dumped from the non-selected cylinder via a fixed choke to a tank. By application of the relevant friction pad in this way to the corresponding disc, a reaction torque independent of the speed of rotation of the disc is transmitted to the rocking shaft 4 of the tubular weapon 1.The value of this actual torque MKtU.I is measured by means of a pressure gauge 27 and supplied to the input of the module 24 (Figure 2) of the control device 20 as a feedback signal. Alternatively, it is possible to measure, instead of the actual torque M, the true pressure P, or P2 in the cymer 6 or 7 and after formation of the difference AP to return this to the control device 20 as a feedback signal (in Figure 1 both M=,l and AP are shown as feedback signals).

In Figure 2 the block 26 represents the tubular weapon 1 and its associated parts comprising the controlled mass to which the control torques are applied under control of the control device 20 and the final control element 25, and whose instantaneous angle is to be compared with the set direction (p,.

By the feedback of the actual torque or pressure difference, it is possible to linearise the non-linear characteristic of the final control stage comprising the element 25, cylinders 6, 7 and pads 10, 11 (due for example to fluctuations of frictional value because of varying temperature). To be more precise, by the pressure feedback AP itself the characteristic of the valve arrangement of 25 is linearised, while by the torque feedback M,, t"., fluctuations of frictional value are also compensated. The manipulating torques applied with the apparatus according to the invention are independent of the angle of pitching of the base and are infinitely adjustable by varying the contact pressure of the friction pads.

in control apparatus of the known kind referred to, forces or torques between moving arts are generated by accelerating or retarding masses, for example, the rotors or engines or the oil masses in an oil motor.

This involves a significant time-delay, which cannot occur with the present invention.

The time-delay which elapses between the time of sending the manipulating signal and the application of the friction pad to the disc, is minimal due to the short distance to be covered and the rapid propagation of pressure in the hydraulic pressure medium.

By virtue of the auxiliary control circuit, with the inclusion of the feedback of the actual torque or the actual pressure, nonlinearities such as fluctuations of frictional value due to temperature variations have no effect upon the regulation of the torque.

The apparatus according to the invention is only put into operation when deviations occur, while in the case of the known apparatus deviations have to be controlled by the coupling between base and mass, which have to be continuously controlled.

This involves a continuous consumption with the known apparatus, which is avoided with the present invention.

WHAT I CLAIM IS: 1. Apparatus for the positioning and position-stabilisation of an inert mass supported on a base and movable with at least one degree of freedom, which includes a control device which produces one or more manipulating variables, the number of which depends upon the number of degrees of freedom, and means by which each mani ulating variable is respectively transformed into a force which presses at least one first part arranged on the mass against at least one second part arranged on the base whilst the second part is moving relatively to the first part, whereby a positioning or position-stabilising frictional force or torque acting on the mass is created by the relative sliding movement between the said two parts.

2. Apparatus according to Claim 1, in which a separate manipulating variable is sssigned to each degree of freedom of the mass.

3. Apparatus according to Claims I or 2 in which each manipulating variable is individually controllable.

4. Apparatus according to any one of Claims I to 3, in which said second part is a rotating disc and said first part is a friction pad which can be pressed against the disc.

5. Apparatus according to Claim 4, in which the disc is rotationally supported on the base and is continuously driven.

6. Apparatus according to Claim 4 or Claim 5, in which for each degree of freedom there are provided as two of the said second parts a pair of contra-rotating discs with each of which a respective friction pad is associated, and in which the friction pads which comprise two of the said first parts can be operated separately from one another.

7. Apparatus according to any one of claims I to 6 in which the control device controls the alignment of the inert mass with respect to a given, and if necessary variable, set direction.

8. Apparatus according to Claim 7, in which the deviation in direction (h) of the mass from the set direction represents the input quantity of the control device.

9. Apparatus according to Claim 8, in which in addition, signals representing the rate of change (A5R) of the deviation in direction and the square (+2) formed from the rate of change are produced in the control device.

10. Apparatus as claimed in Claim 8 or Claim 9 in which the control device supplies the or each manipulating variable to a fmal control stage by which it is transformed into the frictional force or torque, and in which a quantity corresponding to the output of the final control stage to the controlled mass is fed back to the control device to linearise the characteristic of the final control stage.

11. Apparatus according to Claim 8 or Claim 9 or Claim 10, in which a signal corresponding to the contact pressure created by pressing said first part against said second part and measured at the final control stage is fed back to the control device.

12. Apparatus as claimed in Claim 4, or in any one of Claims 5 to 11 when dependent on Claim 4, in which the output signal of the control device is supplied as a control signal to the input of a variable flow control valve device by which the supply of pressurised hydraulic fluid to hydraulic actuator coupled to the or each friction pad is controlled, the pressure medium being supplied from a pump via the valve device to the respective hydraulic actuator and being returned therefrom via a fixed choke to a tank.

13. Apparatus according to any one of Claims 1 to 12, in which the inert mass is supported in low-friction bearings.

14. Apparatus according to Claim 13, in which the inert mass is supported in two plain bearings each with two concentric bearing sleeves, one of which is continuously rotating.

15. Apparatus according to Claim 14, in which the two rotating bearing sleeves are driven in contra-rotatiqn.

16. Apparatus according to any one of Claims 1 to 15, in which the base is the hull of a track-laying vehicle and the inert mass is a weapon.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. disc, is minimal due to the short distance to be covered and the rapid propagation of pressure in the hydraulic pressure medium. By virtue of the auxiliary control circuit, with the inclusion of the feedback of the actual torque or the actual pressure, nonlinearities such as fluctuations of frictional value due to temperature variations have no effect upon the regulation of the torque. The apparatus according to the invention is only put into operation when deviations occur, while in the case of the known apparatus deviations have to be controlled by the coupling between base and mass, which have to be continuously controlled. This involves a continuous consumption with the known apparatus, which is avoided with the present invention. WHAT I CLAIM IS:

1. Apparatus for the positioning and position-stabilisation of an inert mass supported on a base and movable with at least one degree of freedom, which includes a control device which produces one or more manipulating variables, the number of which depends upon the number of degrees of freedom, and means by which each mani ulating variable is respectively transformed into a force which presses at least one first part arranged on the mass against at least one second part arranged on the base whilst the second part is moving relatively to the first part, whereby a positioning or position-stabilising frictional force or torque acting on the mass is created by the relative sliding movement between the said two parts.

17. Apparatus for positioning and

position-stabilising a weapon, as specifically described herein with reference to the accompanying drawings.