DE2302878A1 - DEVICE AND METHOD FOR DETERMINING THE ANGLE BETWEEN A BODY AND A REFERENCE AXIS - Google Patents

Description

Device and method for determining the angle between a body and a reference axis The invention relates to a transmission device for determination the angle between a body and a given reference axis. You dealt continue with a method for such an angle determination using of a corresponding device.

The device according to the invention can be used particularly well in the determination the angular position of objects in relation to a reference axis or reference plane or the angular relationship between two objects, one example is determination of the skew winding F e.g. of the camber or the toe-in, the steering wheels of a vehicle. However, this example should be given without limitation, since there are further possible applications for the expert if the device and its method of use will be explained in more detail. However, it seems sufficient the invention in relation to the determination of the angles of inclination of vehicle wheels to be explained in more detail.

The invention has for its object to provide a device which no physical connections between the lfinkel-Hesselemente required, which continues to operate in a position along a reference axis parallel to the actual axis with regard to the angular relationship to the actual axis * body to be examined or of bodies, the electrical and optical Properties should be such that angle measurements can be made directly. Finally, it should allow the device according to the invention in a simple way Method of examining angles between bodies. des To solve this problem a transmission device of the type mentioned is proposed according to the invention, which is characterized by the fact that a light projector is oriented towards the body is that its light beam is normally directed along the reference axis and thereby fulfills a known angular relationship to the body, that at a distance from the projector on the reference axis, sensing elements for the light beam are arranged so that the projector is independent of the body on both sides of the reference axis It is pivotable that the sensing elements give a response signal when the light beam hits produce that a signal voltage generator together with the device for pivoting of the projector can be actuated and one of the angular position of the light beam opposite generates a signal voltage proportional to its known angular relationship, and that a display device is connected to the voltage generator which shows the voltage directly in angular units.

The device described above is exemplary of a preferred one Method according to the invention for determining the angular position of a body with respect to one another a reference axis, which consists in that a ray of light along the reference axis and an angle that includes the angle between the body and the reference axis is pivoted so that a voltage is generated which is temporal with the light beam pivoting changed in one direction over the swivel angle range that the light beam in the angular position of the body relative to the reference axis and scanned at the point in time the scanning of the light beam, the voltage value is determined, and that finally this voltage value is translated into an angle display.

The device and its method of use make use of rays of light as a transmission medium, leaving no physical connection between the source for the light beam and the light beam sensing elements to establish a relationship is required for the purpose of angle measurement. Furthermore, there is no need after external stationary cards or mirrors and there is no need for previous alignment or adjustment to create a reference plane or 'axis.

In the case of application of the invention to the steering wheels of a vehicle Each wheel is provided with a unit that is both a light beam transmitter as well as a light beam detector. These units are arranged so that they lie on a common reference axis, which is the actual axis of rotation the wheels are parallel with the units placed in positions which are free of interference from the wheel and in direct line of sight of each other. Each transmitter projects a narrow beam of light in a direction perpendicular to the plane of the wheel on which it is mounted and along the reference axis in direction on the opposite unit. Each unit also contains one Light beam detector capable of detecting the incidence of the light beam from the to feel the opposite unit. These units are then electrically using an arithmetic stand or similar device connected, whereby upon finding of a light beam a translation or transmission into a visual display of the angle taken by the wheels with respect to the reference axis takes place. Since the The reference axis is parallel to the actual axis, the visual indicator gives a direct reading of the angle measurements that are being made.

By using motors and cam or cam disks in of each unit, the narrow beam of light from each unit is repeated over an angle pivoted, which includes all angles whose measurement can be expected. Each light beam falls on the light detector of the opposite, unit cooperating with the first unit. When the rays are detected or are determined, an analog voltage signal, which with the pivoting the beams are synchronized, generated in each unit, so the voltage signal the angle between the beam and the plane of the wheel to which the units are attached are, is proportional. At the same time, each When the beam touches the detector on the opposite side, the beam generates a signal generated, which causes a determination of the analog signal. The. to the exact The voltage present at the time of detection is taken from a storage circuit This voltage is supplied by means of suitable measuring devices that Use resistance switching and compensation circuits to display the required Translated or transferred angle.

Further features, details and advantages of the invention result can be derived from the following description of a preferred exemplary embodiment the drawing as well as from the other claims.

They show: FIG. 1 schematically shows a partial plan view of a part of a vehicle which has steerable wheels on which the inventive Device for the purpose of determining the lead or. Mounted camber angle of the wheels is; Figure 2 is an elevational view of the arrangement of Figure 1 along line 2-2 on the outside of the right wheel, mounting an angle measuring unit should be illustrated, while the opposite unit in similar Way is mounted; FIG. 3 shows a section along line 3-3 in FIG. 1; Figure 4 a Section along line 4-4 in Figure 3; Figure 5 is a section along the line 5-5 in Figure 3; FIG. 6 shows a section along line 6-6 in FIG. 3 and opposite to the view of Figure 5; FIG. 7 shows a further section along line 7-7 in FIG 3 and opposite to the view in FIG. 6; Figure 8 is a diagram showing the cooperating units for the vehicle wheels according to Figure 1 and the associated electronic equipment associated therewith showing the interaction of the Light beam transmitter on the right wheel and the beam detector on the opposite Wheel is illustrated; FIG. 9 shows the angle of the Pivoting the light beam in relation to the cam or cam disk rotation, which causes the light beam to pivot; FIG. 9A is one related to the illustration A graph related to FIG. 9, with an analog voltage signal is set in relation to the cam disk rotation, the pivoting of the legs of the light beam and FIG. 10 shows a simplified block diagram of the * are assigned to the unit shown in FIG. 1 belonging to the right wheel, with the light beam detected there the necessary response to generate a Display of the desired angle triggers and the diagram is to be understood in such a way that it shows the electronic elements which the opposite --- unit assigned to the left wheel. * Components that correspond to the electronic Elements are usually housed in a frame away from the vehicle, as indicated in FIG.

In the drawings, FIG. 1 shows a schematic plan view represent the steerable wheels and the associated frame of a vehicle in which the frame part 10 has connecting arms 11 and 12 which have a pivot bearing for the Wheels 13 and 14 form. The device according to the invention is operationally connected mounted on the outer surface of each wheel in the manner shown in Figure 2 so that the Device is arranged in a position that is parallel to the plane the wheel rotation lies.

In Figure 2, the right vehicle wheel 13 carries an adapter, which comprises a main slide 15 which carries a bracket 16 which is about the pivot axis A can swing freely.

The carriage 15 sits on a pair of rods 17, which in turn engage in a transverse part 18, on the hardened spaced apart Elements 19 are attached, which can act on the flange of the wheel rim 20. Below the carriage 15, an adjustable transverse part 21 is provided, which carries a third hardened element 22 which also engages the rim flange. The transverse part 21 is adjustable to adapt to the diameter of the rim flange. The carriage 15 is movable along the rods 17 so that its pivot axis A can be aligned with the shaft axis of the wheel. The carriage 15 is with an arm 23 is provided as a support for a rod 24, which is now to be described Alignment device carries, which, however, is a unit in the present illustration 25 of a pair of cooperating units of the angular position transmitter includes. The rod 24 must be in a horizontal position when the Unit 25 is used to measure the wheel angle (toe-in). To that end is a corresponding weight 26 is attached to the rod 24 opposite the unit 25. The arm 24 is correspondingly long, so that the unit 25 is outside the circumference of the wheel 13 can be stored. The opposite one, with the unit 25 cooperating unit 25A is similarly mounted on left wheel 14, so that the units 25 and 25A, as the drawing clearly shows, face each other in the field of vision.

Figures 3 to 7 of the drawing illustrate the details the right-hand unit 25. It should be noted, however, that the following The description can also be applied to the left-hand unit 25A accordingly. In Figure 3, the arm 24 is a hollow profile and carries an alignment element 27, which engages in a slot 28 of a pivot block 29. The slot 28 is vertical molded into a second slot 28A, making the block 29 at right angles in two Positions lying opposite one another can be rotated, namely that shown in FIG Position and a position which is rotated by 9QO in relation to this.

The pivot block 29 is attached to a flange by means of machine screws 30 31 attached to the upper part of a frame piece 32. The frame has an enlarged lower flange 33. A part 34 of a housing is with its top wall between the frame flange 31 and the pivot block 29 attached. Opposite, drooping Walls extend to floor-side, inward-facing flanges. Of the Frame 32 carries a synchronous motor 35, which has a corresponding gear housing 36 has, from which a drive shaft 37 extends through the frame 32, of a gear wheel 38 and a cam disk or a cam 39 (on the same Wave). The gear 38 meshes with a second gear 40 on a shaft, which is mounted on the frame, penetrates it and with the shaft of a rotor is connected in a potentiometer 42.

The potentiometer is enclosed in a suitable housing, which is held by the base 43 attached to the frame 32. The main shaft of the motor 34 carries a light interrupter disk 44 (Figure 7), which with the The speed of the motor is rotating.

In Figures 3, 4 and 7 a light beam projector is visible, which has a swivel ring part 46 on the underside of the flange 33 of the frame is fixed in a position in which there are vertically aligned pivot elements 47 wearing. The projector includes a body 48 which has an aperture Element (not shown) for creating a light source of very small size encloses. The body 48 carries a corresponding holder 49 for an incandescent lamp 50, which are in axial alignment with the horizontal axis of the body 48 and the Opening for the light beam is supported. The body 48 is in the area of the transverse slot 51 cut open, making it possible is that the extensive Area of the light interrupter disk 44 in front of the light beam formed in the body can move past. The body 48 extends past the breaker disk slot 51 in the form of a lens mount 52, one for projecting a narrow light beam B (Figure 4) through the opening 53 in a depending wall of the housing 34 suitable Lens assembly includes. The outer end of the lens mount 52 (Figure 5) carries a ring holder 54 which is provided with an arm 55 which is raised into a position is directed, in which the peripheral surfaces of the cam 39 attack it. The arm 55 is resilient against the circumference of the cam due to the interaction a pin 56 (FIG. 3) on the arm 55 and a spring acting on the arm 56 57 held. The spring -57 is held at its base 58 on the frame 32.

With regard to the mounting type of the light projector body 48 extends the lens mount 52 through a suitable opening (Figure 6) in the frame 32. The Opening 59 is large enough to pivot the projector body 48 and the Socket 52 in a horizontal plane around that defined by the pin 47 (Figure 3) Allow vertical axis. The pivoting movement is due to the interaction the cam 39 and the spring 57 controlled. As shown in Figure 5, wetness, presses the spring 57 against the pin 56 on the arm 55, making the arm 55 at the point of minimum radius of the cam 39 rests. In this view the cam disk 39 rotates counterclockwise.

With this movement, the arm 55 becomes due to the linear enlargement Moved to the right in the cam profile up to point M at an angle of rotation of 2400 is achieved. The cam profile or its Diameter over the remaining 1200 of the rotational movement. Because of this training the lens mount becomes through the cam profile over two thirds of its arc line 52 is moved in one direction so that the light beam B pivots over a path of movement is chosen so that it includes all angles of inclination of the wheel, their occurrence may be expected includes. The last third of the arch of the The cam allows the lens barrel 52 to be returned to its original position S. While the light beam B over a search angle from S to M and back to S is pivoted, the potentiometer is turned at the same time, in one 1: 1 ratio so that the pivoting movement of the light beam B with the potentiometer response is coordinated.

The unit of Figure 3 is provided with a bracket 60 for a photocell element 61 provided, which next to the housing opening 53 and directly below the outer End of the lens mount 52 is arranged. The clamp 60 carries even a housing 62 which contains the parts of the amplifier circuit belonging to the photocell contains.

As a glance at FIG. 8 shows, the units are 25 and 25A each connected via lines 63 and 64 to a console housing 65 in which the electronic equipment, which will be described below, in is housed in the usual way, but with the exception of the respective housing 62, which contain the amplifiers for the light beam detectors 61. The console 65 carries the visual display instruments 66 and 66A in a clearly visible position.

As FIG. 8 shows, the units 25 and 25A are at a distance from one another arranged on the reference axis R (which is also shown in FIG. 1) in such a way that the detector photocell 61A in the unit 25A associated with the left wheel is in a position in which it is from the opposite unit 25 receives the emitted light beam.

The light beam projector 52 (Figure 3) is over an angle of the angular position corresponding to the point in time zero into an angular position according to a cam disk rotation of 2400, which is shifted from the zero position is pivoted. In the zero position determined on the basis of the cam disk rotation of the light beam this encloses an angle β with the arm 24. While themselves the light beam moves towards the 2400 cam position, it sweeps over the detector 61A in the unit 25A at time T1. The angle X that the ray of light includes T1 with the arm 24 at this point in time, is the angle to be determined. The procedure is preferably such that the beam makes the pivoting movement over the first 2400 of cam rotation at substantially half speed compared to the speed when returning to the zero position. This movement is achieved by a cam disk 39 (Figure 5), which with constant Speed rotates around 3600 and a linear angular movement of the light beam generated during rotation. The cam 39 causes a back and forth movement Pivoting movement of the beam with each revolution, the first panning movement during 2400 of the cam disk rotation takes place, while the return movement 1200 of this Movement claimed. An equal but opposite movement is made with regard to of the light beam generated from the unit 25A in the direction of the unit 25 is sent out. In this way, each ray of light creates when it hits the detector the opposite unit at time T1 passes a signal, which is proportional to the angle X with respect to the arm 24 or 24A. Each of the signals is amplified in the amplifiers 62 and 62A and via the lines 63 and 64 of the Console 65 transmitted for analysis and visual display. The analysis of the signal from a detector is shown graphically in Figure 9 and 9A Way done. In Figure 9, the beam angle varies proportionally over an angle to 2400 of the cam rotation.

The ray describes a linear movement along curve 67, while moving in its first pan range. The return panning process takes place according to curve 68 back to the zero position. This movement of the beam is repeated many times with the purpose of continuously that in the electronic Equipment of the console 65 to record the detected signal. Simultaneously with the swivel movement of the jet is the rotor 35 (Figure 6) via the gears 38 and 40 in a ratio 1: 1 connected to the potentiometer 42 to rotate its sliding contact. figure 9A graphically shows the linear analog signal voltage versus rotational position the cam 39 (Figure 3).

The signal voltage follows the linear curve 69. However, as soon as the Voltage exceeds the reference voltage value VR, the beam is in the Return swing motion.

This state of tension is sensed and used to create a To prevent recording of the captured signal during the return swing.

As a result, FIG. 9 shows the angular orientation of the light beam regarding the cam disk rotation. The beam orientation angle can be set on the Measuring instrument up to each value can be recorded so that it all angle which are to be investigated involves adding the appropriate cam arrangement is chosen.

In Figure 9A, the motion drive is also shown by the cam 39 of the potentiometer illustrates which an electrical Signal voltage generated that changes linearly with the cam rotation. In this way, the rotation of the cam disk between 0 and 2400 generates a potentiometer signal voltage, which is analogous to the angular course of the light beam.

From the above description it can be seen that for formation a reference axis R, starting from which angle measurements are made, a corresponding one Light beam detector, for example a photocell 61, arranged on the R axis that it is touched by the light beam B as it swings back and forth will. Exactly at the point in time when the light beam B hit the detector is, the signal voltage of the potentiometer 42 is fed to a storage circuit 70, in which it is held. This voltage, which is now stored in the circuit 70, represents represents an analog value for the angular alignment of the light beam if it is the reference axis R passes and the detector 61 grazes.

This voltage represents the beam angle. The angle :: that is the orientation of the entire unit with respect to the reference axis R, becomes from the angle ß at which it is around a constant, through the physical Arrangement of the unit is generated angle, and the measured angle @ determined. Due to this fact, by means of corresponding setting circuits 71 and zeroing circuits 72 with respect to those stored in the memory array 70 Voltage this voltage on a voltage-sensitive display instrument 66 (or 66A) than the actual angular orientation of the unit 25 (or 25A) opposite the reference axis R. Since the unit is reliable on the subject to be examined Wheel was attached, its angular orientation is accordingly known and can be displayed as a result.

The method according to the exemplary embodiment is to be described below will.

The light beam B emitted by a unit (25 or 25A) is not a constant luminous flux, as it has a frequency of around 1,000 sec-1 is chopped or interrupted by the breaker disk 44 (Figure 7). That Detector system 61 or 61A is sensitive to light chopped at this frequency and strives to reject all other frequencies. This fact helps to eliminate indifference or interference from light sources and changes in the surrounding light When the light beam B detects the opposite detector, there is a certain period of time, during which the action of the light beam on the detector continues. this is due to the finite width of the light beam. During that period of time the detector receives a burst of light chopped at 1,00O sec. 1 and generates Pulses which are passed on to the associated amplifier 62 (FIG. 10). The amplifier 62 gives essentially the same, but significantly amplified Signal to a monostable multivibrator 73. The leading edge of the light pulse signal triggers the multivibrator 73, which is a negative running pulse for the differentiator 74 generated. The negative impulse remains fixed for a period of time that is slightly larger is than the period of time during which the light pulse is received. The differentiator 74 produces a very narrow pulse that coincides with the leading edge of the signal at the monostable Multivibrator 73 and differentiator 74 coincide.

When the light beam hits the detector during its first pivoting movement sweeps over, a blocking device 75 enables a narrow gate pulse known length the gate 76 is operated by a switch in the gate during the duration is closed. This impulse also coincides with the leading edge of the signal at elements 75, 74, 73 and 62 together. The impulse has a familiar one Duration. Therefore, the generated by the potentiometer 42 and voltage sent into the circuit to memory 70 is the voltage value at the same Time. This signal conditioning is required to ensure the accuracy of the end the reading time T1 with regard to the angular position of the light beam ß (Figure 8) to ensure. The end is always with the same slight delay after the initial contact of the light beam with the detector during the first Beam swivel reached. The voltage now stored in memory 70 remains unchanged until the next gate pulse during the next first pivoting process of the light beam occurs, at which point the processes in the circuits be repeated.

The circuit according to FIG. 10 contains an isolating amplifier 77, which the energy for driving the display instrument (66 or 66A) is generated and at the same time the voltage stored in the "memory" 70 isolates and protects. The setting circle 71 and the zero circle 72 ensure a corresponding scale division or measuring range selection, so that the measured value display can be made in an appropriate manner.

As already mentioned above in connection with FIGS. 8, 9 and 9A vurde; hears the light beam during the cam disk rotation from 2400 to '3600 the return swivel motion out during which he obviously sweep over the detector and cause a gate pulse to occur. As a result of the limited width of the light beam B and the opposite pivoting direction however, an error would be created in the timing of the gate pulse.

This erroneous pulse is therefore attached by the trap circuit 75 prevented from triggering the gate circuit.

It can be seen from the illustration of FIG. 9 that upon rotation of the cam 39 between 240 and 3600, the voltage of the potentiometer 42 is greater than a certain voltage VR generated by the reference voltage source 78 will. This reference voltage is predetermined and constant to the trap circuit 75 (Fig 10) supplied. The blocking circuit 75 compares that at the reference voltage source 78 predetermined voltage with the incoming voltage from the potentiometer 42. So long the potentiometer voltage is higher than the reference voltage VR *, all any gate pulse generated prevented from triggering the gate 76. To this This prevents an error signal during the backward pivoting of the light beam reaches the memory 70. * (Figure 9A) According to the description above, should be clear that the device described can measure any angular relationship between a moving body and a fixed reference plane or axis can be used, the measurement being carried out by an angular position transmitter is achieved. As described above, the transmitter is well suited for an improved Method for measuring angular relationships, especially where the angles are small, so that these small angles are enlarged, as it were, for easier testing can be.

Claims (12)

Patent claims: 1. Transmission device for determining the angle between a body and a predetermined reference axis, characterized in that a light projector (48-52) is aligned with respect to the body (13, 14) so that its light beam (B) is normally directed along the reference axis (R) while being a known one Angular relationship (ß) towards the body that fulfills that at a distance from the projector sensing elements (61, 61A) for the Llc, ltstrahl are arranged on the reference axis, that the projector can be pivoted independently of the body on both sides of the reference axis is that the sensing elements give a response signal when the light beam hits produce that a signal voltage generator (42) together with the device (36) can be actuated to pivot the projector and one of the angular positions () of the The signal voltage of the light beam is proportional to its known angular relationship and that a display device (65, 66) is connected to the voltage generator which shows the voltage directly in units of angle. 2. Apparatus according to claim 1, characterized in that the light projector (48 - 52) and the voltage generator (42) have a common drive (36), an angular swivel () of the projector and a signal voltage generation proportional to the swivel angle (0). 3. Apparatus according to claim 1 or 2, characterized in that the Voltage generator (42) and the sensing elements (16, 61A) in a circuit (Fig, 10) are switched on, which one with the sensing elements for the purpose of responding gate direction (76) connected to the light beam (B), a device (75) for supplying the signal voltage to the gate device and memory circuit elements (70) which is supplied by the gate device from the sensing elements Signal voltage received and connected to the voltage display device (663 are. 4. Device according to one or more of claims 1 to 3, characterized in that that the light beam (B) emitted by the projector (48-52) has an interrupt frequency which is much higher than that of the surrounding light, which increases the sensitivity the sensing elements (16) for the light beam reduced compared to the ambient light will. 5. Apparatus according to claim 3, characterized in that the circuit (Fig. 10) a device (75, 78) for differentiating the pivoting direction of the light projector (48-52) and to prevent the gate device (76) from operating in one Swivel direction (M-S). 6. Device, in particular according to one or more of the preceding Claims, characterized in that the projector (48 - 52) from the body (13, 14, 24) is carried near the reference axis (R) that the angle (PI) by which the Projector is pivotable on both sides of the reference axis, one to be expected Includes the angle of deviation (@) of the body in relation to the reference axis, that the voltage generator (42) during its operation one of the angular pivoting of the light beam (B) generated proportional signal voltage that with the voltage generator an electrical gate (76) is connected, which via electrical components (73, 74, 75) is connected to the sensing element (61, 62) for the light beam that the sensing element when receiving the light beam at the angle of the body opposite the reference axis generates an electrical pulse that opens the gate so that the value of the signal voltage at the time the light beam is received by the Sensing element is passed, and that electrical Measuring elements (66) are connected to the gate, the signal voltage at the time of gate opening and this stress in units of the angular relationship (X) of the body to Translate reference axis. 7. Apparatus according to claim 6, characterized in that the sensing element (61, 62) for the light beam (B) and the voltage generator (42) electrically via a circuit (75, 78) are interconnected, the gate (76) only in a swivel direction (S-M) of the projector emitting the light beam (48 - 52) opens. 8. Apparatus according to claim 6 or 7, characterized in that the The projector (48-52) is arranged opposite the body (13, 14, 24) in such a way that the angular pivoting () of the light beam (B) on both sides of the reference axis (R) takes place. 9. Procedure for determining the angle between a body and a reference axis, characterized in that a light beam (B) along the Reference axis (R) emitted by the body (13, 14, 24) that the light beam back and forth by an angle (0) in a plane containing the reference axis an angular range is pivoted, which the desired angle Cx) between the body and the reference axis includes that through the light beam one of the Angular position (G) of the body signal proportional to the projected light beam is generated, and that finally the generated signal in an angle display (66) is converted with respect to the reference axis. 10. The method according to claim 9, characterized in that a voltage is generated, which is timed with the light beam pivoting in one direction (S-M) changes over the swivel angle range () that the light beam (B) in the desired angular position * of the body (13, 14, 24) in relation to the reference axis (R) scanned and the voltage value at the point in time (T1) of the scanning of the light beam is determined, and that finally this voltage value in an angle display (66) is translated. * (x) 11. The method according to claim 9, characterized in that that for the electrical display of the angle (X) one for the angular position (G) of the light beam (B) analog signal voltage is generated which is converted into an angle display (66) the signal-to-voltage conversion upon detection of the collapse of the Light beam with the reference axis (R) is triggered. 12. The method, in particular according to one or more of the claims 9 to 11, characterized in that a reference plane of the body (13, 14, 24) at any angle (X) to be determined relative to the reference axis (R) that a light beam (B) is placed along from the reference plane of the body the reference axis is sent that a signal generating, more responsive to light Detector (61) on the reference axis and at a distance from the reference plane of the body is arranged that the projected light beam in a containing the reference plane Plane and over an angle (which includes the angle (X) to be determined that a signal is generated whose characteristic curve is proportional to the angle (G) between the plane of the body and the projected ray of light, and that that generated signal and the detector signal into a reading of the angle to be determined encoder of the reference axis. Blank page