GB2320956A - Target detector - Google Patents

Abstract

A robot device for detecting a ground target and comprising a spherical rolling member (2) with drive units (14) moving it forward intermittently in individual steps and a sensor arrangement (12) activated between the movement steps in order to locate the target. In the inoperative phase between successive motion steps the sensor arrangement and the drive units are brought into a position for target location or to optimise thrust momentum in the next motion step using a supporting device (4) which is automatically retracted into the interior of the sphere during the rolling motion steps and extendible beyond the surface of the sphere in between successive motion steps. The device (4) comprises supporting members (6,8,10) disposed on different respective sphere diameter lines, stationary relative to the rolling member, at the corners of a tetrahedron inscribed in the sphere, for securing the rolling member in a defined position, stationary relative to the ground. In a modification (Fig 2) only two supporting members are used.

Description

2320956 40971C/wszz T ITLE i 0 1 i A Robc)t Device for,-,'iroi-lnd Target

The i'nvention a device, fr _letecting a ground 7,ai,get.

48 L.39 and.15 (-J-1;-t;,31c)se automatic lcl,2a+,4Llg wheeled are a J1 supporting rremberS which are forward', nr by si-lort -.hrus-'s jet (.r-ives.

1'Lmi-,t---d use -:,w-ng their the -fa,-t that they a performance, part ic-ular ly Robots kn,--,wn -from DE 955, c,-),-ni:)rise fre,,--].y-r(-l.'-,-ing owing to their high ease of walking, are much more capable nf and covering large distane.es wit', l-,w ener.:=;,,.7 driven by a pulse (--',rive.

with a radial of the sphere in the rest-i-ig suc(--.essiv-- motion steps, momenturri of drive-, it by the -, r r!, 7-1, -- _ r-- -led ro bots j::, --f- c- - i walking :)ver::,rciund.

_Al 5 or DE-Al-34 s i.) e r c: 1 members Urript ion. They are sphereal body t-trid a-- ve the nases between t. ignited, the drive acts in tile 2 directi,in o-"' the next motion step and substantially L U parallel to the surface nf the ground. As a result, however, of forward motion of an unguided sphere in the aforementioned manner, t',-ie robot may come to a st,:'_p after rulling into any position, i.e. with any point on the surface- of the sphere in (-..ontact with the grc.)und,.:- tnd may require expensive control and an additional drive. rne--hanis,n, such as separa-c.e tangentially-acting c.,:)ritrol drives, so that in the resting phase the spherical robo can be re-orientated into a defined rolling which is optimum as regards the arrangement of sensors for target location and the drive for the next step.

One. object of this invention is to provide a robot device,j"nich moves forward and in the form of an unguided sphei.i,2a! body, so that the robot can be positioned in a stable manner and in a defined rolling position between successive motion steps, using a simple energy-saving construction.

According to this invention there is provided a robot devIce- for detecting a ground target and comprising a rolling rnember having a drive which moves i-,, forwar(-;' intermittently in -'ndividual steps and also havJnR a sensor arrangement which locates the target and is activated between the rn(--)v(--ment steps, wherein the 1 -.3 rolling member comprises a supporting device which is withdrawn into the interior of the sphere during the rolling movement steps, is extendible beyond the surface of the sphere during movement steps and comprises supporting members secured to the rolling merriber and disposed on spherical diameter lines for supporting and securing zii-- rolling rrierriber --,n the ground when it has rolled into a defined position.

In the robot according to this invention and as a result of the arrangement and construction of the supporting device and without adversely affecting the forward motion in the form of an unguided rolling spherical member, the number of possible rest positions is restricted to a few, i.e. preferably two or four, the robot occupying each position automatically after the supporting device has extended, thus substantially reducing the constructional and control system of a sensor and drive system oriented in optimum position in the resting phase, with the further advantage that the supporting device operates with low energy arid, in the extended state, guarantees stable, exact positioning of the robot in the position into which it. has rolle-d.

In accordance with a further advantageous feature of this invention, the supporting device comprises two members which each have a pivotable weight extendible - 4 therewith and, when the supporting device is extended, is in an eccentric position so as to tilt the robot into stable rest position, in which the robot is supported by and by the surface of the ground. This restricts the positions to two such only two predetermined a the two supporting members sphere, which rests on the number of possible resting surface of the sphere has which, after activation of reach the top position, in geometrical north pole of t that the points the supporting device, can other words can (:onstit-ite the he 5phere, each point associated with an equatorial plane which is stationary relative to the sphere and is horizontally aligned when the correspondin.a north pole point is in the top position. This restriction to two stable rolling positions further reduces the constructional and control expense for an effective sensor and drive system.

According however to an alternative and a particularly preferred embodiment of the invention, the supporting device comprises four supporting members disposed at the respective corners of a regular 'letrahedron inscribed in the sphere. in this supporT, system, the roboth;-:s foiir possible rest P(-siti(:,ns, associated with north pole points unif(--,rrrily over the surface -.)f the sphere. This ensure-,, particularly in open country, that the robot is re'Liably 1 cl re-orientated in each respective supported position, and as a result of the favourable position of the ground contact points, the rolling member is prevented frorn tilting in an efficient manner. Admittedly the expensean efficiently positioned sensor and drive system is higher than in the embodiment w-lt',,i two supporting elements but is still 'Kept within narrow limits.

In order, by means of a ensure that the supporting _Js pr.)t,-ct,ed external influences when retracted, and J,:,e not.

interfere with the geometry the siDhere, the members preferably comprise cup-s'r-i.::ipe('k end when the supporting members are form rt:l.

f the surface of a sphere.

According to another important aspect of this invention, the supporting device, in a simple construction, is in the form of a rotary drive when the supporting members are in the extended takes over the rotation of the robot around a ve-rtical axis extending through the respective north-pole point, as required for target location ancl for alignment next motion ste,-,. In a o en-:)ure a goc)d on the =, r (1) 1-1 1- d the supporting wheels used for rotation preferably a ribbed crossover section on their outer pe-riphery arid advantageously, in order further tu simplify the 1 1 W 11 r) - construction are formed by -,he cup-shaped end pieces of the supporting members.

Each supporting element may prc,vi(Je-ri with a sensor extendible together therewith, so that during the rolling motion -.)f the robot the sensors are in a protected position inside. surfacc- of the sphere and, when the robot is in the resting phase, they are moved i a mechanically simple manner sJrr)i,)ltait--ously with the supporting members, into an ope-razing position extending beyond the surface of the with the further advantage that, when the si-zrjr)(--)rtii-ig me-mbers are disposed in a tetrahedron, each selisor in the extended position is situated on tha-Tpoint of the spherical member which is a,vantagr--ol,s _for target orientation. Advantageously in. this case, particularly in the case of directional', sensors, which have to be rotated around a vertical axis for efficient target orientation and in order to simplify the rotary drive, the individual sensors are secured to the supporting wheel and the supporting wheels are driven in rotation independently from one another, so that, for the purpose of target crientati(--n, the- situated at the north pole of the sphere- when the robot is in the supporting position, together with the sensor se-cured therewith, is initially driven alone and si-i,-)seqt-ic-,ritly, r depending on the result of target location, the supporting wheels of the other supporting members on the ground are rotated around the vertical axis in order to rotate the entire robot, until the robot is exactly aligned in the direction of the next motion step.

Por fine adjustment of the supporting position, particularly on rough ground the supporting members have controllable extension lengths variable independently of one another.

if, as preferred, the roller drive of the roller, the initially mentioned manner, comprises pulse drives secured to the roller member and with a radial direction of thrust relative to the centre of the sphere, and the drive actuated for each successive motion step has to be aligned parallel to the ground surface when in the rest position with a view to efficient use of the generated momentum, another important simplification of the construction and control, in conjunction with the previously described support device, can be made in the robot according to the invention in that the drive units are disposed in the neighbourhood of equatorial circles of the rolling member parallel to the tetrahedral surfaces or to the ground contact surfaces formed when the supporting device is in the extended state. As a result of this geometrical arrangement of the drives, 1 1 n 2 5 when the supporting device is extended, eacl.) group of drives along an equatorial plane is automatically orientated in position without the need for additional control expense or unifc)rTfily dense coverage ef the entire spherical surface by a number of individual drives. in this case, in order advantageously to distribute the supporting members and drives over the spherical surface, the drives are each disposed opposite one of the supporting members and, when using solid fuel drives used only for a single motion step each drive may be distributed among a group of geometrically closely adJacent individual drives with substantiaLly the same direction of thrust, so that the rotational positioning of the robot, required in the supporting position for aligning the thrust power for the next step, can be carried (Dut around the vertical axis at little control expense and irrespective of which of the individual drives on the equatorial plane parallel to the --ground has already been used in a preceding motion step or is still available as a drive.

This invention is explained in more detail with reference to two embodiments illustrated in the drawings by way of examples.

in the drawings:

Pigure 'L shows a robot device with an extended - 9 Figure 2 supporting device and supporting members disposed in a tetrahedron, and shows a robot device with two supporting members during the rolling motion (Figure 2a) and in the resting and supported position with the extended supporting members (Eigure 2b).

Referring to the drawing, Figure 1 shows a robot 2 in the form of a spherical member rolling unguided on M. ground during the individual motion steps and comprising a support device 4 which is retracted during the rolling motion and comprises four supporting members disposed at the corners of a tetrahedron inscribed in the sphere. Each supporting member comprises for example a supporting shaft 8, telescopically extendible by an electric motor in the direction of a diameter of the sphere and drivable around the shaft axis by another electric motor (not shown). A supporting wheel 10 having profiled peripheral ribs is secured to the supporting shaft 8 and is in the form of a cup-shaped closure member which serves as part of the spherical surface when the supporting device 4 is in the retracted position. The extension length and the rotary drive of each individual supporting member 6 are individually controllable. A sensor 12, such as a direction-finding sensor sensitive )5 to sound, radar, infrared or laser light, is secured to the underside of each supporting wheel 10.

The four boundary surfaces of the tetrahedron defining the geometrical arrangement of the supporting members 6 relative to the rolling member 2 determine f(I)ur different equatorial planes or surfaces on the spherical surface, each parallel to one of the tetrahedraI surfaces, and shown by broken 'Lines in Figure 1 and marked A-D. On each equatorial circle A-D, a drive uni 14.1-14.4 is disposed in opposition to a respective supporting member 6, that is at a place on the equatorial surface which is separated by an are length about times the sphere radius from a point on the sphericaI surface opposite one of the supporting members 6, as shown most clearly in Figure 1 in the case of the drive unit 14.1 which is disposed on the equatorial eire'Le A opposite the left supporting member 06 in Figure 1, being separated by the are length S from the point X on the surface diametrically opposite the supporting member 6.

Each drive unit 14 consists of a group of close-ly adjacent individual drives 16 having substantially the same direction of thrust, radially towards the centre of the sphere. Each individual motion step of thspherical member 2 is brought about by igniting one of the individual drives 16, in the form of solid fuel 11 1 In, drives.

When the spherical robot 2 has come to a stop at the end of a motion step, all four supporting members 6 are initially extended together, with the result that one of the preset equatorial planes (plane A in Figure 1) is aligned parallel to the ground contact surface, and the supporting member 6 whose shaft access perpendicular to this equatorial plane position whereupon the rotary drive extends reaches the top associated with this supporting member 6 is actuated and the sensor secured to the supporting wheel 10 and now rotating around the shaft axis is activated. Next, depending on the result measured by this sensor 12, the rotary drives of the three remaining supporting members 6 on the ground are actuated together so that their supporting wheels 10 cause the entire spherical robot 2 to rotate around the shaft axis of the supporting member 6 in the top position, until the direction of thrust of the drive unit 14.1 disposed on the equatorial plane A parallel to the ground coincides with the desired direction of rolling in the next motion step. After the supporting members 6 have retracted, the spherical robot 2 is made to roll by a brief drive pulse generated by igniting an as yet unused individual drive 16 in the drive unit 14.1 and carries out the next motion step, and the process is 12 repeated until the target is reached or until no individual engine 16 remains in service.

If the spherical robot 2 has to be brought automatically into a preset target region, the directier of rolling is kept constant, for example by means of a compass, during a given number of successive motion steps. After the target area has been reached, the direction of rolling until the target is located is determined either in accordance with a preset search pattern or at random, for example by leaving out the previously described rotary positioning of the spherical rotor 2 by means of the supporting wheels 10. The control commands required for the individual working steps are generated by a signal processing unit (not shown) disposed inside the sphere and optionally associated with the direction- sensing compass and position sensors, such as mercury switches, for determining which equatorial plane is parallel to the ground.

The spherical robot in Figure 2, where structural components corresponding to she first embodiment are marked by the same reference numerals plus 100, differs from Figure 1 mainly in that the supporting device 104 contains only two instead of four supporting members 108, the supporting shafts 108 being individually extendible 1 1 -) and having their axes disposed on different sphere diameters. Correspondingly, when the supporting device 104 is extended there are only two possible supporting positions in which the rolling body 102 is held by the rolling members 106 in a defined position, the respective ground contact surface being disposed in a plane extending tangentially to the spherical surface and the supporting wheels 110 touching the outer periphery when in the extended state. Each of the two possible ground contact surfaces is associat-ed with an equatorial plane A or B parallel thereto on which, as before, a drive unit 114. 1 to 114.2 comprising a -number of individual drive in i ts 116 is disposed in -.)ppositic,n to the supporting members 106. On the half of the sphere- the supporting members 106, at a place on the spherical surface on a spherical radius at right angles to the equatorial plane A or B, d-Lrectional sensors 11'L2 are (disposed and can be extended beyond the spherical surface when the rolling member 102 is in the supporting position and, in the extended state, can be rotated either by a separate electric motor or by rotation of.the entire r--.,lling body 102 on the supporting wheels 110 around the aforementioned spherical radius.

In order to ensure that the rolling member 102 arrives at one of the two defined supporting positions 14 even when the supporting members 106 are at a position remote from the ground at the end of the rolling motion, the supporting members 1006 are extended not simultaneously but in succession, and the supporting wheels 110, owing to their weight, serve as pivoting weights for tilting the rolling member 102 into the defined rolling posiJti,_-)n in which one of the equatorial circles (circle A in Figure 2B) is aligned parallel to the ground and the associated sensor 112 is in the top position and can now be extended and activated. In other respects the construction and mode of operation of the spherical robot 112,2 is substantially the same as in the f irst embodiment.

Instead of disposing the directional sensors 12 or 112 in the top or north facing pole position of the spherical robot 2, it may be advantageous, in the case of certain kinds of directional-sensor systems, to dispose pairs of diametrically opposite sensors on a latitude circle extending between the individual north poles and the associated equatorial plane, in which case the orbital motion of -rhe sensors around the vertical axis, when the spherical robot is in the supported position, will be brought about lby the supporting- whee 1 drive.

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Claims (14)

1. A robot device for detecting a ground target and comprising a spherical rolling member having a drive which moves it forward intermittently in individual steps and also having a sensor arrangement which locates the target and is activated between the movement steps, wherein the rolling member comprises a supporting device which is withdrawn into the interior of the sphere. during the rolling movement steps, is extendible beyond the surface of the sphere during successive movement steps and comprises supporting members secured to the rolling member and disposed on spherical diameter lines for supporting and securing the rolling member on the ground when it has rolled into a defined position.

2. A robot device according to Claim 1, wherein the supporting device comprises two supporting members with respective pivoting weights extendible therewith and for tilting the rolling member into a defined rolling position.

3. A robot device according to Claim 1, wherein the supporting device comprises four supporting members disposed at the respective corners of a regular 16 - tetrahedron inscribed in the sphere.

4. A robot device according to any one of the preceding claims, wherein the supporting members comprise cupshaped end members which, when the supporting members are retracted, form a part of the surface of the sphere.

5. A robot device to any one of the preceding claims, wherein the supporting members comprise supporting wheels which in the extended state are driven in rotation in order to rotate the rolling member around a vertical axis.

6. A robot device according to Claim 5, wherein the supporting wheels have a ribbed cross-section on the outer periphery.

7. A robot device according to Claims 4, 5 or 6, wherein the end members are in the form of supporting wheels.

8. A robot device according to any one of the preceding claims, wherein each supporting member comprises a which is extendible in common therewith.

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9. A robot device according to Claim 8, as limited by any one of Claims 5 to 7, wherein ILhe sensor is non-rotatably connected to the supporting wheel of supporting element, and the supporting wheels are rotationally driven independently of one another.

10. A robot device according to any one of the preceding claims, wherein the supporting members have controllable extension lengths which are variable independently of one another.

11. A robot device according -ro any one of the preceding claims, driven by pulse drive units secured to the rolling member and with a radial direction of thrust relative to the centre of the sphere, wherein the drive units are disposed in the neighbourhood of equatorial circles of the rolling member parallel to the tetrahedral surfaces or to the ground contact surfaces formed when the supporting device is in the extended state.

12. A robot device according to Claim 11, wherein the drive units are each disposed opposite a respective supporting member.

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13. A robot device according to Claim 10 or Ill, wherein each drive unit comprises a group of individual drives having substantially the same direction of thrust.

14. A robot device constructed and arranged to function as described herein and exemplified with reference tr, the drawings.

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