GB1605104A - Positioning and position-stabilising apparatus for a mass movable supported on a base - Google Patents

Description

(54) POSITIONING AND POSITION-STABILIZING APPARATUS FOR A MASS MOVABLY SUPPORTED ON A BASE (71) I, LUDWIG PIETZSCH, a German National, of 75 Karlsruhe, Richard Wagner Strasse 5, West 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 refers to apparatus for positioning and stabilizing the position of an inert mass supported on a base so as to be movable relatively thereto with at least one degree of freedom, including a control device which produces one or more manipulating variables, the number of which may correspond to the number of the degrees of freedom.

The invention comprises certain improvements in or modifications of that forming the subject of my co-copending patent application No 6545/73 (Serial No 1605103), which claims one such positioning and position-stabilising apparatus having means whereby each manipulating 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.In one arrangement the control device receives as input a signal corresponding to the value of the deviation in direction of the mass, and generates additional signals proportional to the rate of change of the deviation, and the square of the rate of change, which are summated with the input signal to control the output of the control device.

By such means in accordance with the above patent application rapid and precise positioning and stabilizing of the position of the mass, e.g. the tubular weapon on a track-laying vehicle, are achieved independently of perturbed motions of the base.

If a tubular weapon arranged on a tracklaying vehicle is to be aimed at a target, the tubular weapon must first of all be aimed roughly at the target from e.g. a locked starting position, so that a proportionallycoarse deviation from the aimed direction has to be corrected. Next the tubular weapon, for compensation of the perturbed motions of, for example, the track-laying vehicle travelling over uneven ground and/ or of the likewise moving target, must be reset very accurately in the case of small deviations in direction. To fix the desired value of the datum direction in both cases there can be used a directional beam or aiming line between the track-laying vehicle and the target, produced by an optical target-detector apparatus. If the tubular weapon is to be brought back to its starting position, the desired starting position, e.g.

the locked position of the tubular weapon on the track-laying vehicle, is advantageously used as the datum direction. In this case it is frequently necessary to make a large change in direction until the tubular weapon has reached its starting position again.

According to one aspect of the present invention, apparatus for positioning and position-stabilising an inert mass supported on a base so as to be movable relatively thereto with at least one degree of freedom of angular movement, includes a control device which produces at least one manipulating variable, and means by which the or each manipulating variable is 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 two said parts, and includes means for supplying to the control device an input signal which represents the directional deviation of the mass from a datum direction, the control device including means for generating from the input signal first and second function signals which represent respectively the rate of change ot the said directional deviation and the square of the said rate of change, and means for selectively producing, either a first output signal dependent wholly or mainly on both the input signal and the second function signal for use as the manipulating variable in correcting large directional deviations, or a second output signal dependent wholly or mainly on the input signal alone, for use as the manipulating variable in correcting small directional deviations.

Thus a distinction is made between the two main working conditions, viz., the correction of large deviations in direction with high speed in comparatively coarse approximation, and very accurate alignment in the case of small deviations in direction.

It is proposed that for these two main working conditions different output signals are obtained from the control device as the manipulating variable. From this there results for Working Condition I (rapid correction of large directional deviations with coarse approximation to the desired value) regulation at optimum speed, i.e., "soft" regulation, and in Working Condition II (very accurate correction of small directional deviations) "hard" regulation. Advantageously quantities corresponding to the directional deviation, its rate of change and the square of its rate of change are each multiplied by a factor and summated to provide a resultant signal from which the desired output signal of the control device is derived.

The arrangement is preferably such that the factors are variable, and that the factor which belongs to the square of the rate of change of the directional deviation is during correction of small deviations (stabilizing) made relatively small or zero, whilst during correction of large deviations (aiming) the factor belonging to the rate of change of the directional deviation is made relatively small or zero.

According to another aspect of the invention, apparatus for positioning and positionstabilising an inert mass supported on a base so as to be movable relatively thereto with at least one degree of freedom, includes a control device which produces at least one manipulating variable, and means by which the manipulating variable is respectively transformed into a force which presses at least one first part arranged on the mass against at least one second part on the base whilst the second part is moving relatively to the first part, whereby a positioning or position-stabilizing frictional force or torque acting on the mass is created by the relative sliding movement between the said two parts, and including a locking mechanism acting between the mass and the base. This enables the mass, e.g., a tubular weapon, to be locked in a desired position, e.g. a rest or loading position.

If the two parts of the mechanism which are movable relative to one another are arranged to be pressed together by means of a pressure fluid, the locking mechanism may include a locking cylinder associated with the mass and connected into the pressure fluid.circuit and with a plunger sliding in it, one end of which projects from the locking cylinder and can cooperate in the advanced position of the plunger with a recess in a part associated with the base.

The invention according to either of its said aspects may be carried into practice in various ways, but one specific embodiment thereof will now be described in detail by way of example only, and with reference to the accompanying drawings, in which: Figure I is a diagram of a mechanism in accordance with my patent application No.

6545/73, (Serial No. 1605103) which is also applicable to for the present invention, but in which a locking mechanism is not displayed; Figure 2 is a block diagram of the control device, modified in accordance with one aspect of the invention, of the mechanism shown in Figure 1; Figure 3 is a diagram of a pressure fluid circuit with a positioning mechanism for pressing together the parts movable relative to one another of Figure 1, and a locking mechanism, and Figure 4 is a graph showing the operating cycle of the mechanism of Figures 1 to 3.

Figure 1 shows a tubular weapon 1 which is supported by bearings 2 and 3 on the body (not shown) of a track-laying vehicle to be able to pivot through an angle p. Each bearing has two concentric bearing shells one of which is continuously driven, in the opposite direction to the driven bearing shell of the other bearing. It is thereby ensured that during pivoting of the tubular weapon 1 only the hydrodynamic bearing friction has to be overcome, which is smaller than the limiting or mixed friction in the starting zone and largely independent of the pivoting speed. A brake caliper 5 is connected firmly with the pivot shaft 4 of the tubular weapon 1. The brake caliper 5 has in each arm a cylinder 6, 7 with a piston 8, 9 supported therein, each of which cylinders can actuate a friction pad 10, 11. The friction pads 10, 11 are carried by the rods of the pistons 8, 9 and act on brake discs 12, 13 which are supported rotatably at 14, 15 by means of a gear housing 16A secured to the vehicle body (not shown). The brake discs 12, 13 are driven continuously in opposite directions via a bevel gear designated as a whole by the reference number 16 from a drive 17, e.g., a hydraulic drive.

In this manner definite frictional driving couples (torques) in opposite directions can be applied by the caliper 5 to the pivot shaft 4 of the tubular weapon, by selectively subjecting either the piston 9 or the piston 8 to a pressure P1 or to a pressure P2 respectively, to cause the associated friction pad 11 or 10 to engage the brake disc 13 or 12 with a proportional pressure. A setting device 25 actuates one or other of the cylinders 6, 7 to operate its respective friction pad 10 or 11, on the command of a controller device indicated in Figure 1 by the box 20 and shown in detail in Figure 2, when the tubular weapon has a direction deviating from the desired direction.

The datum value of the alignment of the tubular weapon 1 is preset, e.g., by an optical target-detector apparatus 21, which presets a directional angle s, for example in elevation. This preset angle ps is compared with the instantaneous angle j of the tubular weapon 1 measured at 26. From the comparison the angular deviation Ap is derived, which is fed into the controller 20.

As shown in Figure 2 there is formed ion a module 22 of the controller 20 a quantityA corresponding to the rate of change of the angular deviation, and a quantity A which corresponds to the square of that rate of change and distinguishes the sense of the rate of change. Then each of the three said quantities A A, AIA is multiplied at 30, 31, 32 by a variable factor ko, k, and k2 respectively. The quantities so obtained, kid0, klAp, k2A IA are added together in a summation unit 23 and form one input signal to a comparator unit 24 of the controller.With the deviation in direction and its rate of change remaining the same, this input signal to the unit 24 is variable by altering the constants. For example, the constant k2 can be made zero so that as the actual input signal only k(, + klAp remains. In this case "hard" regulation is achieved, which is advantageously employed with very accurate control at small deviations. If the factor k, is made relatively small or zero, on the other hand, regulation at optimum speed, i.e., "soft" regulation, is achieved, which is employed advantageously for rapid compensation of a large deviation A0.

The output signal emitted by the summation unit 23 is a quantity functionally linked with the desired driving torque Ms and is fed to the comparator unit 24. As a second input quantity this comparator unit 24 can receive a feedback signal measured by a capsuletype dynamometer 27 at the shaft 4, the measured signal being proportional to the actual moment or shaft torque Mi and being multiplied in a module 33 by a factor k3 before being fed to the unit 24. The output signal i from the comparator unit 24 is fed to the setting device 25 which will now be described with reference to Figure 3.

The setting device 25 comprises a control valve arrangement which depending upon the angular direction of the required following motion of the tubular weapon 1 which is to be produced, supplies pressure fluid to act on either the piston 8 or the piston 9 respectively associated with the friction pads 10 and 11. As shown in Figure 3, the pressure fluid is supplied from a constantpressure hydraulic supply having a motor 40 and a pump 41, and is fed via a solenoidoperated change-over valve 42, a non-return valve 43 and an adjustable flow-valve 44 to the respective piston-space 45 of the selected cylinder 6 or 7 (in Figure 3 for the sake of simplicity only the cylinder 6 whose piston 8 cooperates with the brake-disc 12 is shown).The selected friction pad 10 or 11 is thereby pressed against the associated brake-disc 12 or 13 journalled in the housing 16A on the body, and a reaction torque independent of the speed of the discs will be transmitted by the caliper 5 as a driving torque to the shaft 4, the sense of the driving torque depending upon which cylinder 6 or 7 and friction pad 10 or 11 have been selected and actuated by the associated valve 44. The pressure fluid is fed back to a tank 47 via a fixed constriction 46. The non-return valve 43 prevents sucking of air into the installation. The adjustable flow valve 44 can be formed as a throttling servo-valve with electrical control by the controller 20. The flows, and hence the pressures P, and P2, are thereby proportional to the control currents from the controller 20.

As in the main application No. 6545/73 (Serial No. 1605103), a fluid pressure feedback Ap representing the difference between the actual fluid pressures applied at the same time to the cylinders 6 and 7, may be derived and supplied as a further input to the controller 20, as an alternative or in addition to the torque feedback input Mi from the dynamometer 27. The pressure feedback Ap enables the characteristic of the valve arrangement itself to be linearised, whereas the torque feedback Mj enables fluctuation in the coefficient of friction at the pads 10 and 11 due to rise in temperature to be compensated.

A double-acting locking cylinder 51 is connected into the pressure fluid circuit via pipes 49 and 50 and is accommodated in a part solidly connected with the shaft 4, e.g., in the caliper 5. The axis of the shaft 4 is designated in Figure 3 by 4'. The pipes 49, 50 open into the two working spaces 53, 54 in the locking cylinder 51 on the two sides of a piston 55 sliding therein. The piston rod 56 of the piston 55 projects through the space 54 and to the outside via a bore in the part 5.

In the body of the track-laying vehicle a recess 57 fitting the piston rod 56 is so arranged that the piston 56 in a certain position of rotation of the tubular weapon 1 can enter the recess 57. The change-over valve 42 is so designed that by its operation pressure fluid can be fed selectively either via the pipe 49 or via the pipe 50, and fluid returning respectively via the other pipe can flow down into a tank 58. The locking described can also be performed frictionally. In that case the recess 57 is omitted and the piston 56 is pressed in frictional contact against the vehicle body. The locking described serves to secure the tubular weapon 1 in the loading position or in a rest position respectively.

With the aid of the curves shown in Figure 4 the cycle of operation of the mechanism will now be explained. Time t is plotted as the common abscissa, starting from origin A. Different salient operating conditions are shown on the abscissa by the letters A, B, C, D and E. At A and E the directional deviation Ap of the tubular weapon 1 with respect to a target is represented on the ordinate. At C the directional deviation A0R of the tubular weapon with respect to a locked position, e.g., the loading position, of the tubular weapon is plotted.

The cycle of operation will now be described from left to right in chronological sequence starting at A in Figure 4.

At A the mechanism is lying in the locked position in which the piston rod 56 projects into the recess 57. The tubular weapon is now to be aimed at a target; for that purpose the locking is released by actuation of the change-over valve 42 into its position shown in Figure 3 to admit pressure fluid into the space 54 in the locking cylinder 51. The controller 20 is initially operated in Working Condition I for "soft" regulation in which the factors ko and k2 predominate and kt is relatively small or zero. The at first large deviation is thereby rapidly reduced so that the tubular weapon is pivoted rapidly from the point 60 to the point 61 in the interval of time AB.When the deviation value has fallen after point 61 to within a preset range E the controller 20 is switched over automatically from the "soft" Working Condition I to "hard" Working Condition II in which the constant k2 is made relatively small or zero and the constant ko is made to predominate. Very accurate following movement by the tubular weapon in dependence upon the perturbed motions of the tracklaying vehicle and/or of the target is hereby possible. The "hard" regulation is maintaned up to the point of time C.

At this point of time C the tubular weapon is to be brought into the locked position. For this purpose a locking signal is emitted whereby the locking position of the tubular weapon, which may be identical with the loading position, is preset as the new desired direction value. The de viationApR from this locking position will in general at first be large, as is indicated by the point 62 in Figure 4. The controller is now again switched onto "soft" working with constants ko and k2 predominating until the locking position 63 is reached after the interval of time C-D. At time D a signal "lock" is given to the change-over valve 42 which is thereby switched over into a position in which it feeds pressure fluid via the pipe 49 to the space 53 in the locking cylinder 51.The piston rod 56 is thereby inserted into the recess 57 to lock the weapon in its locked position. This happens at point 63. The locked position is maintained until the point of time E. At this point of time the tubular weapon is to be aimed at a new target. For this purpose the desired direction onto the target is again preset as the desired value and all proceeds in the same way as in the interval of time between A and C, that is, first of all the large directional deviation A is rapidly reduced in "soft" working until the point 65 is reached, and then the tubular weapon is kept following the target very accurately by "hard" regulation, as long as may be required.

WHAT WE CLAIM IS: 1. Apparatus for positioning and position-stabilising an inert mass supported on a base so as to be movable relatively thereto with at least one degree of freedom of angular movement, which includes a control device which produces at least one manipulating variable, and means by which the or each manipulating variable is 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 two said parts, and which includes means for supplying to the control device an input signal which represents the directional deviation of the mass from a datum direction, the control device including means for generating from the input signal first and second function signals which represent respectively the rate of change of the said directional deviation and the square of the said rate of change, and means for selectively producing, either a first output signal dependent wholly or

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

Claims (12)

**WARNING** start of CLMS field may overlap end of DESC **. designated in Figure 3 by 4'. The pipes 49, 50 open into the two working spaces 53, 54 in the locking cylinder 51 on the two sides of a piston 55 sliding therein. The piston rod 56 of the piston 55 projects through the space 54 and to the outside via a bore in the part 5. In the body of the track-laying vehicle a recess 57 fitting the piston rod 56 is so arranged that the piston 56 in a certain position of rotation of the tubular weapon 1 can enter the recess 57. The change-over valve 42 is so designed that by its operation pressure fluid can be fed selectively either via the pipe 49 or via the pipe 50, and fluid returning respectively via the other pipe can flow down into a tank 58. The locking described can also be performed frictionally. In that case the recess 57 is omitted and the piston 56 is pressed in frictional contact against the vehicle body. The locking described serves to secure the tubular weapon 1 in the loading position or in a rest position respectively. With the aid of the curves shown in Figure 4 the cycle of operation of the mechanism will now be explained. Time t is plotted as the common abscissa, starting from origin A. Different salient operating conditions are shown on the abscissa by the letters A, B, C, D and E. At A and E the directional deviation Ap of the tubular weapon 1 with respect to a target is represented on the ordinate. At C the directional deviation A0R of the tubular weapon with respect to a locked position, e.g., the loading position, of the tubular weapon is plotted. The cycle of operation will now be described from left to right in chronological sequence starting at A in Figure 4. At A the mechanism is lying in the locked position in which the piston rod 56 projects into the recess 57. The tubular weapon is now to be aimed at a target; for that purpose the locking is released by actuation of the change-over valve 42 into its position shown in Figure 3 to admit pressure fluid into the space 54 in the locking cylinder 51. The controller 20 is initially operated in Working Condition I for "soft" regulation in which the factors ko and k2 predominate and kt is relatively small or zero. The at first large deviation is thereby rapidly reduced so that the tubular weapon is pivoted rapidly from the point 60 to the point 61 in the interval of time AB.When the deviation value has fallen after point 61 to within a preset range E the controller 20 is switched over automatically from the "soft" Working Condition I to "hard" Working Condition II in which the constant k2 is made relatively small or zero and the constant ko is made to predominate. Very accurate following movement by the tubular weapon in dependence upon the perturbed motions of the tracklaying vehicle and/or of the target is hereby possible. The "hard" regulation is maintaned up to the point of time C. At this point of time C the tubular weapon is to be brought into the locked position. For this purpose a locking signal is emitted whereby the locking position of the tubular weapon, which may be identical with the loading position, is preset as the new desired direction value. The de viationApR from this locking position will in general at first be large, as is indicated by the point 62 in Figure 4. The controller is now again switched onto "soft" working with constants ko and k2 predominating until the locking position 63 is reached after the interval of time C-D. At time D a signal "lock" is given to the change-over valve 42 which is thereby switched over into a position in which it feeds pressure fluid via the pipe 49 to the space 53 in the locking cylinder 51.The piston rod 56 is thereby inserted into the recess 57 to lock the weapon in its locked position. This happens at point 63. The locked position is maintained until the point of time E. At this point of time the tubular weapon is to be aimed at a new target. For this purpose the desired direction onto the target is again preset as the desired value and all proceeds in the same way as in the interval of time between A and C, that is, first of all the large directional deviation A is rapidly reduced in "soft" working until the point 65 is reached, and then the tubular weapon is kept following the target very accurately by "hard" regulation, as long as may be required. WHAT WE CLAIM IS:

1. Apparatus for positioning and position-stabilising an inert mass supported on a base so as to be movable relatively thereto with at least one degree of freedom of angular movement, which includes a control device which produces at least one manipulating variable, and means by which the or each manipulating variable is 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 two said parts, and which includes means for supplying to the control device an input signal which represents the directional deviation of the mass from a datum direction, the control device including means for generating from the input signal first and second function signals which represent respectively the rate of change of the said directional deviation and the square of the said rate of change, and means for selectively producing, either a first output signal dependent wholly or

mainly on both the input signal and the second function signal for use as the manipulating variable in correcting large direc tlonal deviations, or a second output signal dependent wholly or mainly on the input signal alone, for use as the manipulating variable in correcting small directional deviations.

2. Apparatus as claimed in Claim 1 which includes means for multiplying the input signal (or an equivalent intermediate signal derived therefrom) and each of the two function signals by respective multiplying factors, means for altering the value of at least one of the multiplying factors relative to the others, and means for summing the three multiplied signals to product a resultant signal on which the output signal of the control device is independent, and in which selection of the said first or second output signal is effected by alteration of at least one of the multiplying factors.

3. Apparatus as claimed in Claim 2 in which means is provided for individually adjusting the multiplying factors.

4. Apparatus as claimed in Claim 3 in which for selection of the second output signal for correction of small directional deviations, the multiplying factor of the second function signal is adJusted to zero or to a relatively small value, and the multiplying factor of the input signal (or its equivalent intermediate signal) is adjusted to a value such that the input signal predominates.

5. Apparatus as claimed in Claim 3 or Claim 4 in which, for selection of the first output signal for correction of large directional deviations, e.g. for aiming,the multiplying factor of the first function signal is adjusted to zero or to a relatively small value.

6. Apparatus for positioning and position-stabilising an inert mass supported on a base so as to be movable relatively thereto with at least one degree of freedom, including a control device which produces at least one manipulating variable, and means by which the manipulating 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, and including a locking mechanism acting between the mass and the base.

7. Apparatus as claimed in Claim 6 in combination with any one of Claim 1 to 5.

8. Apparatus as claimed in Claim 6 or Claim 7, in which hydraulic pressure means is used to press the said first and second parts together to generate the manipulating variable, and in which the locking mechanism comprises a hydraulic locking plunger and a cooperating recess, one associated with the mass and the other with the base, the locking plunger being connected in the pressure fluid circuit so that one end of the plunger constitutes a detent which can be advanced into locking engagement in the recess.

9. Apparatus as claimed in Claim 8, in which the locking plunger and the hydraulic pressure means for pressing the said two parts together are both connected via a common change-over valve with the same pressure fluid supply.

10. Apparatus as claimed in any one of Claims 6 to 9, in which the locking mechanism is constructed and arranged to lock the mass in a first datum direction corresponding to a locking position of the mass, and in which means is provided for aiming a directional beam or sight from a point on the possibly-moving base at a possiblymoving target point outside the base, the aimed direction of the beam or sight establishing another datum direction deviations from which of the unlocked mass are to be corrected.

11. Apparatus as claimed in any one of Claims 1 to 10, in which the mass is supported on the base for movement with a plurality of degrees of freedom of angular movement relative thereto and in which the control device produces a corresponding number of the manipulating variables respectively associated with the degrees of freedom.

12. Positioning and position-stabilizing means for an inert mass rotatably mounted on a base, as specifically described herein with reference to Figures 1 and 2, or to Figures 1 to 4, of the accompanying drawings.