EP0829066B1 - Analogue control element - Google Patents

Abstract

A single-axis or multi-axis joystick assembly which is operative with a minimal amount of input force or displacement. As such, the joystick assembly is especially suited for those with severe motor handicaps who have limited movement in their extremities. The joystick assembly includes a housing and a handle operatively mounted to the housing for movement relative thereto. The handle operatively engages a sensor which generates an output signal when an input force is applied to the handle. The output signal is proportional to the input force. Preferably, the sensor is a piezoelectric pressure transducer.

Description

The invention relates to an actuator according to the preamble of claim 1.

Such a control element is used as a joystick for computer inputs (also as a mouse replacement) or as Joysticks for movement control on mobile or stationary devices (as from self-driving disabled lifts, excavators and robots), as a slide for Mixer potentiometer or for changing parameters in the machine control known; generally for the manual specification of a variable scalar size, usually by means of a swivel lever. These known control elements have in common that their manual The greater the deflection to be caused, the greater the resulting deflection Change of variables should be; and that the deflection can be carried out more quickly must, the faster the variable is to change. For function control by Physically handicapped, such as the muscles of the remaining stump of an amputee Acting extremities to control a prosthesis or a vehicle are such Controls hardly or not at all operable, because of the radius of action in which these people still can specifically apply a muscle force, the stroke of such tied off control elements no longer covers. The large input stroke ultimately also requires large installation and Operating space requirements. This shortcoming does not only exist with potentiometric inputs, but generally with position sensors for obtaining analog control signals, such as in Swing lever systems for linear displacements with internal kinematic implementation. In addition, lever systems in actuators often have the disadvantage of being non-linear Reactions to the input stroke on, which makes some control tasks very difficult Control elements in the manner of bending elements with strain gauges according to GB 2 211 280 A or EP 0 151 479 A or with Hall elements according to WO 93 20535 A as sensors basically the same disadvantages. On the other hand, if the manually executable hub is limited, the resolution is reduced and thus the precision and reproducibility the attitude. Apart from that, such actuators are to be actuated via path specifications a technically quite expensive and against mechanical interference such as shock loads, in particular, is a sensitive solution PLUS / MINUS key pairs e.g. for the channel search of a radio receiver or for the volume remote control does not necessarily have to, but the precise fine adjustment of an almost reached default value is cumbersome even with key reaction at two speeds, consequently imprecise in practice.

With the present invention, a robust and dirt-tight encapsulable but smooth-running and vibration-proof analog single or multi-axis control element can be created with which is possible for humans, values with high setting accuracy, reproducibility and dynamics and fatigue-free change over a long period. The rest position (Zero point) should be found particularly safely from any position and the equipment Realization should be inexpensive because it is very simple, compact and functionally reliable.

With regard to the solution according to the invention of these specifications and your not obvious Further training is based on the main claim including the subordinate claims and on the following Description of the drawing and its summary summary referenced at the end.

The present invention is therefore primarily a single or multi-axis Control element that is practically pathless and therefore fatigue-free with minimal Use of force is operated so that it can also be used for the severely handicapped. The The core of this solution is a mechanically stable, preferably indifferent balance balanced, structurally simple but precise suspension of a one- or two-armed lever, as a pressure-transmitting element without play against practically pathless sensors is present. On the other hand, the lever protrudes with its part serving as a handle at the bearing point out of the tightly closable housing, to cross to its bearing shaft or hinge axis to be able to record manual pressure. Compared to the known route-dependent has the invention, practically without mechanical deflection (ie pathless) and play-free actuating element has the advantage that the pressure input direction is not undesired is left, as when moving along a freely definable path in the plane biaxial system. This has a particularly positive effect when controlling the cursor movement about in CAD input. Now, for very precise two-axis specifications, pathless Actuators can also be cascaded because of their handling with little radial play can be arranged one inside the other.

The pressure exerted on the sensor can be integrated in signal processing technology, as long as the pressure remains, and with known pressure dependence of the physical Sensor behavior thus also pressure measurement tasks - as well as when applied via a constant area including force measurement tasks. This is the stroke of the output signal (e.g. the length of a linear cursor movement or the end position of a digital one Display device) depends on the duration of the pressure, and the signal dynamics (e.g. the speed of movement of a cursor on the screen or the speed of change the digital display) from the intensity of the straight, practically pathless, manual in the pressure applied.

This is why this joystick is particularly suitable for industrial use harsh environmental conditions; as well as for operation by even little controlled, no matter whether powerful or weak, minimally sweeping body movements, with for those with disabilities in everyday life or surgeons during surgery with motor aids can control.

In the context of the present description of the invention, the terminology is accepted assumed that the housing of the control element is mounted in a fixed position and from this the Handle protrudes; however, it can also be used within the scope of the present invention be reversed, namely that the control element is mounted on its protruding lever arm, while on the manually accessible housing the actuation force relative to the pressure element (i.e. to the inner lever arm).

Fig. 1

ein erfindungsgemäßes Stellelement mit kugelförmiger Lagerung eines zweiarmigen Hebels und mit gehäuse-achsparalleler Druck-Beanspruchung seiner Sensoren,

Fig.2

ein Stellelement ähnlich demjenigen nach Fig. 1, aber nun mit walzenförmiger Lagerung seiner Handhabe und mit gehäuse-radialer Sensor-Druckbeanspruchung

Fig. 3

zwei koaxial kaskadierte Stellelemente entsprechend demjenigen nach Fig. 1,

Fig. 4

eine Stellelement-Kaskade entsprechend Fig. 3 mit Sensoranordnungen entsprechend Fig.2

Fig. 5

ein Stellelement mit Sensor-Beanspruchung gemäß Fig.2 aber mit einarmigem Handhaben-Hebel und

Fig. 6

ein Stellelement entsprechend Fig.5 aber mit elastischer axialer Abstützung anstelle einer Wälzlager-Aufhängung seiner Handhabe.

In the drawing shows, not quite to scale and abstracted to the essentials,

Fig. 1

an actuating element according to the invention with a spherical bearing of a two-armed lever and with pressure on its sensors parallel to the housing,

Fig. 2

an actuating element similar to that of FIG. 1, but now with a roller-shaped mounting of its handle and with a housing-radial sensor pressure load

Fig. 3

two coaxially cascaded control elements corresponding to that according to FIG. 1,

Fig. 4

an actuating element cascade corresponding to FIG. 3 with sensor arrangements corresponding to FIG. 2

Fig. 5

an actuator with sensor stress according to Figure 2 but with one-armed handle lever and

Fig. 6

an actuator according to Figure 5 but with elastic axial support instead of a roller bearing suspension of his handle.

At a passage 10, a positive projection 11 projects into the Embodiments linear-rod-shaped handle 12 of the actuator from a housing 14 out. Although it can only be pivoted minimally under the influence of lateral pressure, the handle is 12 is supported in an articulated manner on the housing 14, namely by means of a ball joint 18 (FIGS. 1 and 3 - 5), by means of a roller joint 29 (FIG. 2) or by means of a rubber-elastic block 28 (Fig. 6); in each case directly or indirectly between the housing side walls 17 (Fig. 4, 5, 6), in the latter case preferably suspended in a housing top wall 16 (Fig. 1, 2, 3, 4).

With reduced requirements with regard to the precise method of working, the geometrical defined and in relation to the handle 12 axially stiff joints 19 and 29 in principle can also be replaced by rubber brackets, e.g. by vulcanizing on all sides the handle 12 and the housing 14 are connected.

Despite the virtually non-existent movement of the lever from handle 12 and pressure element 15 However, the precise and low-friction, geometrically defined ball or is more advantageous Roller bearings of the joints 19, 29. This reduces the static friction (at the minimum Swiveling due to manual introduction of lateral force into the handle 12), and therefore it is the main reason for the high sensitivity and reproducibility at the Pressurization of the sensors 25. This type of suspension 11 can for example, with a rod of 30 mm in diameter for the handle 12 Response sensitivity of 200 mN must be ensured.

Because of the positive suspension 11 of the rigid structure from handle 12 and Pressure element 15 does not exert pressure on the sensors 25 through axial mechanical Stresses on the handle 12 and thus affects the actuating function alone relevant electrical output value, currently specified by manual cross printing, is not unreproducibly falsified. In rough machine operation or in tiring The operator can thus use the construction of the tower 12 with his fist enclose and support this on the housing cover plate, without this already Excitation of the sensors 25 is caused before the fist is not consciously pivoted and thereby causes a lateral force on the handle 12. Because the axial pressure components are about the precision storage in the suspension 11 of the stable housing 14 included, so do not lead to a load on the sensors 25 Displacement of the pressure element 15; which applies accordingly to tensile forces.

The convex profile of the ball joint 18 can be attached to the handle 12 or directly be formed on its outer surface; such that it projects radially beyond the handle 12. It is resting as free of play as possible in a flat bowl 19 in the form of a hollow spherical segment, which e.g. with the Housing 14 is pressed or is formed directly as part of the housing 14. With undivided Double shell 19-19 can widen its central hole by temporary heating to receive the ball profile 18 in the form of a bearing bush. It is also possible to design the shell 19 as part of the housing in the upper half with resilient elements and so to achieve easier manufacture and assembly. The tight border in Housing 14 with in the axial direction of the handle 12 rigid suspension 11 in the fixed The fulcrum is the main reason for the high reproducibility and Responsiveness of the pressurization of sensors 25, with optimal setting options the external force application requirements in accordance with the lever arm ratios compared to the joint 18 or 29 (in particular compared to the related Properties, for example, in the case of an unstable tip bearing of the lower end of a Swivel lever handle against the bottom of the housing; or at one at the bottom End with a pivotable plate supported handle for uneven Axial pressure exerted on a sensor group according to EP 0 616 298 A).

The conditions are correspondingly advantageous for only single-axis or Roller joint bearing 29 of the lever from handle 12 and pressure element 15 (Fig.5), if So the handle 12 together with its pressure element 15 in the housing 14 by a housing-fixed Shaft is carried - preferably as outlined with the interposition of a sliding, a ball or another bearing 31 within a ring 35 into which the lever splits here. The ring 35 is partially of a hollow cylindrical profile 30 approximately in the adjacent one Surround wall of the housing 14, which again the good sealing of the interior of the housing 14 provides in which the sensors 25 are arranged.

In this roller joint 29 (Fig.2) there is only the manual plane of action transverse to Roller axis, around this. At the ball joint 18 (Fig. 1 and 3-5) and at Rubber block storage 28 (Fig. 6), on the other hand, the outside of the housing 14 e.g. in a Finger recess 32 (Fig. 1, 5, 6) outgoing or equipped with a finger ring 27 (Fig.3) In principle, handle 12 is transversely loaded in any direction relative to housing 14 become; An evaluation then takes place, depending on the arrangement of force sensors 25 in Housing 14, preferably only in two directions orthogonal to one another (FIGS. 1 and 3-6), in which a pressure force acting laterally on the protruding handle 12 after Force parallelogram is broken down. If the ball joint bracket 18 none Protection against rotation is provided, you can advantageously under the pressure direction pending pressure when turning the handle around its longitudinal axis, and thus that Force parallelogram with resultant kept constant. That makes it easier Cursor control for CAD entries. For this effect of twisting the handle Manually initiated shear force is conducive to rigidly tightening the free end of the handle to equip a hat or plate that can be easily gripped by the fingertips (not in the drawing considered). But if this twisting of the handle 12 should not be desired, can also a kind of gimbal suspension from two orthogonal roller bearings for the handle 12 acting in two dimensions.

In the housing 14, the handle 12 is rigid with its pressure element 15 Power transmission to the sensors 25 designed or equipped. The handle 12 and her Depending on the relative location of the articulated bearing 18/28/29, pressure element 15 form together a two-armed (Fig. 1 - 4) or a one-armed (Fig. 5, 6) lever. That is by means of one e.g. longitudinally adjustable counterweight 34 (Fig. 1-5) preferably to indifferent Balance balanced so that the (anyway very minimal) pivoting due to the Introduction of transverse pressure into the handle 12 can be more sensitive, and thus dependent on the position Effects of pressure on the sensors 25 are avoided as far as possible

With a one-armed lever, the tare weight 34 lies outside the actual lever area (between the handle 12 and the element 15 that transmits pressure for the sensors 25), namely beyond the joint 18 (FIG. 5) or 29. Here, the passage opening 10 can also be sealed using a bellows sleeve, for example. The advantage of one-armed lever but the short axial length of the system, i.e. the particularly compact Structure of the balanced, path-free, smooth-running control element.

In both cases is about the leverage (with respect to the handle 12 and pressure-transmitting element 15 each with respect to the suspension 11) and optionally (see below) on elastic constants and prestresses of support bodies 26, and finally also on the responsiveness of the sensors 25, one with stress on the Handle 12 response pressure can be specified constructively. The current pressure loads of the sensors 25, individually or in pairs in a differential circuit, of a signal processing device (inside or) outside the housing 14 become. This device can also implement a signal swing according to the duration or the intensity of the current transverse stress on the handle 12.

The lever of the handle 12 and the pressure element 15 thus protrudes through the opening 10 between the Side walls 17 of the tubular housing 14, which is preferably rectangular in cross section inside. Therein lies the pressure-transmitting element 15 constantly, that is to say without play and in addition if necessary with a certain mechanical preload, parallel (Fig. 1 and 3) or transverse (Fig. 2, 4 - 6) to the axial direction of the handle 12 against the sensors 25, which in turn are supported against this attack against the housing 14. Each sensor 25 can e.g. a semiconductor, a piezo, a magnetostriction, an optical fiber element or any other be analog pressure transducers that work practically without path.

By the interposition of a rigid disc 24 of a defined area between Pressure element 15 and sensor 25 is the manually initiated and according to the Lever ratio translated pressure into a force. The disc 24 evened out at the same time the force acting on the sensor surface, which is more practical, for example It is important for the characteristic curve in polymeric film pressure sensors

An equalization of the pressure transfer to the individual sensors 25 below Ensuring a play-free system of the pressure-transmitting element 15 results from Intermediate layer of only slightly elastically compressible support bodies 26 behind (Fig.1) or in front of (FIG. 3) the sensors 25, which also overload the sensors 25 mechanically exclude. At the same time, they act like a resilient intermediate piece 33 between Handle 12 and pressure element 15 (Fig.1), a clear deflection in the Pressure on the handle. This can be the case for some applications, especially in rough Machine operation, may be desirable to make the manual action more noticeable leave - although as stated in the control element according to the invention no way but only the force is evaluated, which is why this control element works without a path and that flexible intermediate piece 33 must not be too soft

The strain in the interest of higher setting accuracy and reproducibility also despite the minimal pivoting of the element 15 always vertical and to be introduced without tilting into the sensor 25 (or its separately resting disc 24), the pressure is transmitted from element 15 via a spherical intermediate link 22 can be formed on the disc 24 or on the element 15 as a knob. If it is as a separate or integrally formed ring concentrically surrounds the pressure-transmitting element 15 is thereby ensures that twisting has no effect on the current sensor load remains.

Basically, for each (tensile or compressive) direction of stress to be evaluated Handle 12, i.e. for each active axis of the actuator, a pair of sensors 25 each other provided diametrically opposite with respect to the axis of the handle 12. That also makes it possible a difference evaluation, for example to linearize the effective response characteristic Definition of the point of rest or to eliminate non-opposing sensor influences such as due to thermal expansion effects or mechanical Acceleration influences.

In order to reduce costs, only one sensor 25 needs to be used per axis; the second is then, as it were, by a dummy 20 in the form of a Evaluation device (e.g. for digital resistance measurement and time integral formation) connected sensor (Fig. 4 without the connection leads leading to the right) or in the form of only the elastic support body (26) or a separate stiff spring 21 (Fig.2) replaced. The sensor 25, which is now measured per axis alone, is thus through Opposite in the rest position, stiffly elastic, then depending on the direction of the manual cross attack on the handle 12 to increase or decrease its internal pressure humiliate.

Since the handle 12 experiences practically no deflection when force is applied, two can hinged handles 12, 12 coaxially with one another with little radial play be arranged to use one hand e.g. to be able to operate four axes simultaneously. At 3 and 4 are two housings 14, 14 coaxially one above the other assembled. The handle 12 of the lower one runs with radial play through a tubular one Handle 12 of the upper housing 14 and is at the front exit with a cap equipped, which has at least approximately the same outer diameter as the outer handle 12. The same lever ratios are on both sides for both control elements their ball joints 19 for suspension 11 of their handles 12 complied so both Handle 12 are operated with the same characteristic sensitivity. Each is preferred Handle 12 equipped with a phalanx engaging ring 27 in order to no need to wrap around To be able to introduce compressive and tensile forces into the respective handle 12. So can be used with two adjacent fingers of one hand, which on both sides of the separation point between Grip the outer handle 12 and the cap from the side, operate two control elements simultaneously, so control four axes. This variety of operation is still in a tandem arrangement easily doubled if the same system of two nested one again Control elements in reverse orientation (i.e. the caps next to each other) coaxial on the face is mounted in front of it and can thus be operated with two further spread fingers of the same hand is. Overall, this results in an eight-axis control that can be implemented with a single hand.

The control elements designed according to the invention are therefore inexpensive and reliable Executable and largely insensitive due to the encapsulation of the sensors 25 against environmental influences. In terms of operation, they excel in particular at Bearing suspension 11 of the lever-balanced handle 12 by a very extraordinary high responsiveness and through reproducible behavior at the manual introduction of pressure into the handle 12. This promotes the operating options, for example by using only one fingertip - for exerting pressure - not freely on the side of the handle 12 must fit, but - engages in a trough 32 with which the handle 12 on its free Front end can be equipped (Fig. 1, 3, 5).

Claims (10)

1. Analog control element, such as control stick, switching lever, cursor operation or similar part, with a handle (12) which is held in a housing (14), characterized in that a part of a handle (12) which is suspended as a lever is continuously braced, practically without delay, through at least one force sensor (25) against the housing (14), where the sensor (25) produces an output signal, which magnitude depends on a pressure force, acting diagonally with respect to the handle (12).
2. Control element according to Claim 1, characterized in that a pressure sensor (25) is provided as force sensor, onto which pressure can be applied through a rigid transmission surface (disk 24), against which, on its side, the handle (12) is braced by means of a ball-like intermediate member (22).
3. Control element according to Claim 1 or 2, characterized in that the handle (12), which is suspended by an articulation as a lever, is tared by a counterweight (34) to an indifferent equilibrium.
4. Control element according to one of the preceding claims, characterized in that an elastic element (bracing body 26 and/or intermediate part 33) is arranged in a series with the handle (12).
5. Control element according to one of the preceding claims, characterized in that the handle (12) is braced elastically against only one sensor (25).
6. Control element according to one of the preceding claims, characterized in that its handle (12) passes with radial clearance through a pipe, which itself is the handle (12) of a control element according to one of the preceding claims.
7. Control element according to one of Claims 1 to 6, characterized in that the suspension (11) of the handle (12) in the housing (14) is implemented by means of a ball joint (18).
8. Control element according to Claim 7, characterized in that the handle (12), which is suspended so it can rotate about its longitudinal axis, is applied against at least one pressure sensor (25) by means of a ball-shaped circumferential intermediate member (22), directly or through a rigid disk (24).
9. Control element according to one of Claims 1 to 6, characterized in that the suspension (1) of the handle (12) is implemented at the housing (14) by means of at least one roller joint (29).
10. Control element according to one of Claims 1 to 6, characterized in that the suspension (1) of the handle (12) at the housing (14) is implemented by means of a rubber-elastic wedge (28).

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