CN108151946A - Tactile test measurement device and method for determining force-displacement curves in tactile test measurements - Google Patents

Abstract

A tactile test measuring device (1) comprising at least: a holding device (4) for receiving a test object (7); a robot (2) having a manipulator (3) and an actuator, wherein the actuator comprises at least one measuring head (5) with a measuring system (6); and a stabilizing unit, wherein the stabilizing unit comprises a support element (9) and a support seat (8), wherein the measuring head (5) can be fixed in a fixed position relative to the holding device (4) by means of the stabilizing unit.

Description

Tactile test measuring equipment and methods for determining force-displacement curves in tactile test measurements method

technical field

The invention relates to a tactile test measuring device according to the preamble of claim 1 and to a method for determining a force-displacement curve in a tactile test measurement according to the preamble of claim 12 .

Background technique

High-quality switches and keys should feel "textured" and tactilely provide the operator with clear feedback on the operation of the switch. Especially in the automotive sector, operating panels and keys require extremely high quality. For the qualitative evaluation of the switch, a measuring device is used which rapidly moves the test body (test piece) towards the switch over the entire switching stroke. A precise force sensor is used to create a force-displacement map that shows the tactile consequences of the switch (button) to be measured. For this reason, the linear actuator and dynamometer as a unit must be very rigid and not collapse when handling the DUT to prevent measurement deviations.

In industry, robots are increasingly used in tactile measurement technology. In this case, the robot is used to test tactile operating elements and keys, for example keys of operating elements of electrical appliances or vehicles or keys of electronic devices. In this tactile test, the product to be tested is held in a holding/clamping device of the tactile test measuring device. Subsequently, the measuring system, which is arranged as an actuator at one end of the manipulator of the robot, is moved to a test position so that the measuring system can be tested. To this end, the measuring system performs a predetermined test recording on the test object. In this test, for example, a button is pressed on the test object and the associated force-displacement curve is recorded. For this purpose, a precision push rod fixed on the robot head, with a length encoder and a load cell is usually used as the measuring system.

In the measurement of this force-displacement curve, due to the joint limitation and the stiffness of the manipulator (ie, the mechanical arm) may be too low, it is necessary to calibrate the error in the stroke measurement. In this case, the measuring head with the measuring system on the manipulator no longer holds its position stable under increased forces, so that the measuring results are distorted. The higher the test force and the smaller the robot structure, the greater the measurement error. For example, at a maximum test force of 10 Newtons, a test error in the range of 80 to 150 microns occurs. This corresponds, for example, to a measurement error of over 50% that can be reached in measurements with expected switching travels of smartphone keys of around 200 microns, and even in keys/switches of other electrical appliances and/or keys/switches of other electronic devices. Errors of the same order of magnitude may occur.

To minimize this interference, the robots used in the prior art are oversized for their stability. This leads to a surge in the cost of test equipment that, due to its oversized dimensions, can only reduce rather than eliminate measurement error. With larger and stiffer robots, experiments show that the measurement error is still as high as 20%.

Contents of the invention

It is an object of the present invention to provide a tactile measuring device which eliminates, or at least nearly eliminates, measurement errors. Another object of the present invention is to provide a tactile test and measurement device in which oversized robot systems can be eliminated.

To achieve the above objects, the present invention proposes the characterizing parts of claim 1 and claim 12 . Advantageous technical solutions refer to the dependent claims.

The tactile test and measurement device according to the invention comprises at least one holding device for receiving a test object, a robot comprising at least one manipulator and actuator, and a stabilizing unit. The actuator of the robot includes at least one measuring head with a measuring system. The stabilizing unit comprises at least one support element and a support seat, wherein the measuring head can be fixed in a fixed position relative to the holding device by means of the stabilizing unit, whereby a full "rigidity" of the robot and the measuring head relative to the test object can be achieved. As a result, no errors can occur in the distance measurement when determining the force-displacement curve, because the stabilizing unit avoids the mechanical arm elements being limited by the manipulator of the robot by fixing the position of the measuring head relative to the holding device. The shaft joint and no stiffness will cause errors in stroke measurement. By means of the support seat and the support element, stability is increased in the positioning of the robot, whereby the measuring system and the fixedly associated test body cannot collapse during the measurement and thus distort the measurement. As a result, very small robots with low power, such as foldable robots, can also be used, wherein the costs of the tactile test and measuring device can be significantly reduced.

In one embodiment, the robot's manipulator is a multi-section robotic articulated/polyaxial arm consisting of a series of rigid links connected to each other by rotating and/or sliding joints that can be passed through Controllable drive to adjust. The actuators of the robot are located on the free end of the polyaxial arm and are equipped with at least a measuring system. In a typical embodiment, the actuator of the robot comprises a rotary/replacement head equipped both with a measuring head with a measuring system and, for example, with a gripping element suitable for exchanging the test object in the holding direction. In this case, the gripping element makes it possible to insert the test object from the temporary storage area into the holding device and to remove it from it after the test and place it in another temporary storage area, before inserting the new test object from the temporary storage area. The first temporary storage area is inserted into the holding device.

In typical embodiments, the measuring head comprises a support element of a stabilizing unit, or the supporting element of the stabilizing unit is arranged on the measuring head. In this embodiment, the holding device for the test object typically comprises a support seat of the stabilizing unit, or the support seat of the stabilizing unit is arranged on the holding device.

In another embodiment, the bottom plate of the tactile test and measurement device includes a support seat, or the support seat is arranged on the bottom plate of the tactile test and measurement device. Also in this embodiment, the measuring head can be fixed in position relative to the holding device and the test object.

In another embodiment, the measuring head comprises a support seat of a stabilizing unit and the holding means or base plate comprises a supporting element of a stabilizing unit. Alternatively, the support seat of the stabilizing unit can be arranged on the measuring head, or the support element can be arranged on the holding device or the base plate.

In one embodiment, said support element comprises a magnet, for example an electromagnet which can be activated by a current feed. In this embodiment, the support base comprises a magnetic element, eg in the form of a ferromagnetic base or ferromagnetic base element.

In another embodiment, the support seat comprises a receptacle for positively receiving and centering an end element of the support element configured for a positive fit. Furthermore, it is also possible that the end element comprises a magnet, for example an electromagnet, and that the receptacle in the support seat comprises a magnetic element, so that besides the positive connection and centering of the measuring system relative to the test object in the holding device , can also produce a force fit connection. The additional positive accommodation and centering of the support element in the support seat can additionally be used to align the test body of the measuring system with the test object in the holding device more precisely.

Furthermore, in the form-fitting connection of the support seat to the support element, for example, a rotatable end element is used on the support element in order to engage at the rear with the recess of its corresponding support seat, for example by means of a projection on the end element , a bayonet lock can be achieved, whereby the stability of the measuring head relative to the test object can likewise be increased again. Furthermore, it is also possible to use an end element corresponding to the housing, without snapping the element at the rear, preferably a robotic arm pressing the support element into the housing of the support seat, wherein the manipulator of the robot presses the support element into the support The receptacle of the seat applies a force greater than the force exerted by the measurement system on the test object. As a result, distortions of the distance measurement can likewise be eliminated, or at least almost eliminated.

In other embodiments, the support element comprises an adjustable rod element, so that the distance between the measuring head and the holding device can be adjusted via the adjustable rod element depending on the measuring system used. For this purpose, the rod elements of the support element are for example slidably mounted in a unit which can be fixed by fastening elements.

In another embodiment, the support element is configured in a partially flexible manner, for example in the form of a gooseneck or a movable proboscis, which can be stiffened at least temporarily during the measurement. Thus, for example, a measuring head with the same measuring system and the same support element can be used for different test objects to be tested in the support device, because, depending on the size of the test object, through the support element preferably can be controlled by the control unit The flexible element is approached to different points on the support element, and then the flexible element is temporarily stiffened for the measurement. In this case, the entire support element can be configured as a flexible element, and also only partial regions of the flexible element can be formed. As mentioned above, the fastening/contacting of the support element on the support seat takes place here by means of a non-positive and/or form-fit connection.

Preferably, said flexible element is stiffened by current feeding. In other embodiments, the flexible portion of the adjustable flexibility support element can also be stiffened eg by hydraulic and/or pneumatic elements. The flexible element of the support seat can be, for example, a freely movable element in the form of a gooseneck/bend arm which, after reaching the desired position, can be temporarily hardened for tactile measurement, for example by electromagnetic action.

In a typical embodiment, the force-displacement curve is determined using a push rod system comprising at least one advancing element, a travel measuring device, a force measuring device and a test body as the measuring system. The advancing element is, for example, a telescoping spindle, the travel of which is determined by a length encoder as a travel measuring device. Usually a load cell or load cell as known from the prior art is used as measuring device. The test body can be, for example, a button element for actuating a button of the test object, wherein the button element is operatively connected to the force sensor/force-measuring cell.

In addition to the device, another aspect of the invention is a method of determining a force-displacement curve in a tactile test measurement using a tactile test measurement device according to the invention. Here, this method at least includes the following steps:

- insert the test object into the holding device;

- moving the measuring head with the measuring system towards the test object;

- bringing the support element into contact with the support seat of the stabilizing unit;

- the position of the measuring head relative to the holding device and the test object is fixed by means of a stabilizing unit;

- measurement and determination of force-displacement curves are carried out by means of measuring systems;

- releasing the contact of the supporting element with the stabilizing unit and the supporting seat;

- Remove the test object from the holding device.

In typical embodiments, the contact of the support element with the support seat comprises a form fit and/or preferably an electromagnetic force fit.

Description of drawings

Further advantages, features and details of the invention are elucidated by the following description of preferred embodiments with reference to the drawings.

Figure 1 shows a schematic diagram of a tactile test and measurement device reflecting the prior art;

2 shows a schematic diagram of a first embodiment of a tactile test and measurement device according to the present invention;

3 shows a schematic diagram of another embodiment of the tactile test and measurement device according to the present invention;

4 shows a schematic diagram of a measurement system of a tactile test and measurement device according to the present invention;

Figure 5 shows the force-displacement curves recorded by the measurement system;

6 shows a schematic diagram of a tactile test and measurement device according to yet another embodiment of the present invention; and

Fig. 7 shows a schematic view of yet another embodiment of a tactile test measurement device according to the invention, with a support element comprising a flexible element.

Detailed ways

Fig. 1 shows a tactile test and measurement device 1 corresponding to the prior art. In the example shown, the tactile testing and measuring device 1 comprises a robot 2 and a holding device 4 arranged on a base plate 10 . The robot 2 has a multi-axis arm 3 corresponding to the manipulator of the robot. Arranged at the free end of the multi-axis arm 3 of the robot 2 is a measuring head 5 as an actuator, which includes a measuring system 6 . Via the measuring system 6 , it is possible to record the force-displacement curves generated by the measuring system 6 when the key 11 of the test object 7 is actuated.

For this purpose, the test object 7 is inserted into the test object receptacle 23 of the holding device 4 . During the measurement, a propulsion element 16 further comprising a stroke measuring device 17 moves the test body 15, which remains operatively connected to the force measuring device 14, along the shown movement direction 12 onto the key 11 of the test object 7 in order to determine when the key 11 is manipulated. force-displacement curve. In this case, the test body 15 is moved, for example, at a constant speed until the nominal test force/maximum force F _max is reached in the direction of movement 12 towards the key. Restricted by the joints of the multi-axis arm 3 of the robot 2 and the non-rigidity of the multi-axis arm 3, in this tactile test measurement, the error needs to be calibrated in the stroke measurement, because the measuring head 6 on the multi-axis arm 3 acts With an increase in force, its position is no longer stable, but the measuring head moves in the direction of the measuring head movement 13 shown. As a result, the measurement results determined with the measurement system 6 are distorted. In this case, the higher the nominal test force F _max and the smaller the structure of the robot 2 and its multi-axis arm 3 , the greater the measurement error.

FIG. 2 shows a tactile test and measurement device 1 according to the invention, which basically corresponds to the tactile test and measurement device of FIG. 1 . However, compared with the tactile test and measurement device 1 of FIG. 1 , the tactile test and measurement device 1 of FIG. 2 also has a stabilizing unit including a support base 8 and a support element 9 . In the illustrated embodiment, the support element 9 is a magnet 18 which is fixed to the measuring head 5 by means of a rod element 20 via a fastening element 21 . In the illustrated embodiment, the support seat 8 is a magnetic element 19 , for example a ferromagnetic base element 19 . By mounting a magnet 18 on a magnetic element 19, wherein the magnet 18 is, for example, an electromagnet 18, which can be activated by a current feed and can be deactivated again by breaking the circuit, the passage of the measuring head 5 by the support base 8 and the support element is achieved. The stabilizing unit consisting of 9 is positioned and fixed in a fixed position relative to the test object 7 and the holding device 4 . This in particular achieves a constant distance between the measuring head 5 and the button 11 of the test object 7 , so that a movement of the measuring head against the direction of the test movement 12 can be prevented during the determination of the force-displacement measuring curve. Thus, highly accurate tactile test measurement can be realized by simple means.

A further embodiment of a tactile test measuring device 1 according to the invention is shown in FIG. 3 . The difference between the tactile test and measurement device 1 of FIG. 3 and the tactile test and measurement device of FIG. 2 is that, in addition to the measuring head 5, a gripping element 26 is arranged at the free end of the multi-axis arm 3 of the robot 2 as an actuator. , the test object 7 can be transported from the temporary storage area into the test object receptacle of the holding device 4 by means of the gripping element 26 and, after performing the tactile test measurement, can be transported by it to another temporary storage area.

Furthermore, the tactile testing and measuring device 1 of FIG. 3 differs in that, in addition to the support seat 8 in the form of a magnetic element 19, the holding device 4 also comprises a further support seat 8 in the form of a housing 25 corresponding to the support element The end element 24 of 9 is shaped. In other exemplary embodiments, the holding device 4 can comprise a plurality of different support seats 8 , by means of which a force-fit connection or a force-fit and form-fit connection can be obtained between the support element 9 of the stabilizing device and the support seat 8 . For a non-positive and form-fit connection, the receptacle 25 can, for example, be introduced into the magnetic element 19 or be arranged therein.

Furthermore, the tactile test and measurement device 1 of FIG. 3 differs from the tactile test and measurement device of FIG. 2 in that, in this case, the propulsion element 16 of the measurement system 6 does not achieve a horizontal movement, but a vertical movement 12, It is therefore necessary to prevent the measuring head from moving in the vertical direction. In other embodiments, the test movement 12 may be in any direction other than horizontal or vertical, the test movement 12 is always directed towards the test object 7, and the measuring head 5 with the measuring system 6 always passes through the support base 8 and the support element 9. The stabilizing unit maintains a fixed position relative to the test object 7 .

A typical measuring system 6 for determining a force-displacement measurement curve is shown in FIG. 4 , see for example the use case in FIG. 5 . In addition to the advancing element 16, which can be, for example, a precision spindle, the measuring system 6 also includes a travel measuring device 17, which can be, for example, a length encoder known from the prior art. Furthermore, the measuring system 6 comprises a test body 15 , which is operatively connected to the force-measuring device 14 , with which, for example, a button of the test object 7 is actuated in a typical tactile test.

A further embodiment of a tactile test and measurement device 1 according to the invention is shown in FIG. 6 . This tactile test and measurement device essentially corresponds to the tactile test and measurement device 1 of FIG. 3 , which has a holding device 4 as shown in FIG. 2 , so only the distinguishing features are explained in detail.

In this tactile testing and measuring device 1 , the supporting element 9 is composed of a rod element 20 and an electromagnet 18 . Different from the tactile testing and measuring device 1 of FIG. 3 , in this figure, the bottom plate 10 includes a support seat 8 of a stabilizing unit. By bringing the electromagnet 18 into contact with the magnetic element 19 , the measuring head 5 with the measuring system 6 is likewise fixed relative to the test object 7 in the holding device 4 , thereby preventing the measuring head 5 and the measuring system 6 against the test direction 12 movement, thus avoiding measurement errors in travel measurements.

A further embodiment of a tactile test and measurement device 1 according to the invention is shown in FIG. 7 . This tactile test and measurement device basically corresponds to the tactile test and measurement device 1 of FIG. 6 . However, instead of a stabilizing unit with a solid support element in the form of a rod element 20 , a flexible element 26 is used here, which can be stiffened, for example, by means of a current supply, and thus stabilizes the measuring structure accordingly, so that the measuring head 6 cannot be turned against the testing direction. 12 is moved, at most the measuring head 6 is slightly deflected against the test direction 12 . If very small offsets are allowed, it must be ensured that the resulting measurement error is small enough so that the measurement can still adequately infer the tactile sensation of the key 11 to be tested.

In the embodiment of the tactile test measuring device of Fig. 7, the flexible element 26 is designed as a movable "proboscis" and thus can be moved to different positions and angles. As a result, a high degree of flexibility in supporting and fixing the measuring head 6 with the measuring system 5 relative to the test object 7 can be achieved.

A possible solution for the flexibility of the support element 9 of the stabilizing unit of the tactile test and measuring device 1 according to the invention is shown in FIG. , a possible contact of the magnet 18 on the magnetic element 19 of the support seat 8 of the holding device 4 is indicated by the dashed line.

A method for determining a force-displacement curve in a tactile measurement using the tactile test and measurement device 1 according to the present invention is explained below with reference to FIGS. 2 , 4 and 5 .

First, the test object 7 is inserted into the test object receptacle 23 of the holding device 4 of the tactile test measuring device 1 . Subsequently, by means of the multi-axis arm of the robot, the measuring head 5 is moved towards the test object 7 in order to be able to perform tactile test measurements by means of the measuring system 6 . Before carrying out the measurement, the support element 9 of the stabilization unit is brought into contact with the support seat 8 of the stabilization unit. In the exemplary embodiment shown in FIG. 2 , the contacting takes place by means of a non-positive connection of the bearing element to the bearing seat 8 , wherein the electromagnet 18 is activated by a current supply and is connected in a form-fitting manner to the ferromagnetic element 19 . By means of the stabilizing unit, the position of the measuring head is fixed relative to the holding device with the test object, after which the measurement and determination of the force-displacement curve can be carried out by means of the measuring system 6 . In the exemplary embodiment shown, the control and power supply of the measuring system 6 takes place via the connection element 22 .

To determine the force-displacement curve, the test body 15 is first moved by the push element 6 to the key 11 of the test object 7 . In FIG. 5 this is indicated by the start stroke S _Start . Subsequently, the test body 15 is moved further at a constant speed in the direction of the test movement 12 in order to press the button 11 . In this case, the operating force first gradually increases during the stroke until it reaches the inflection point under the operating force (Operating Force) F _O , and then the operating force decreases due to the continued pressing of the button 11 with less resistance until the switch stroke S _Schalt ends. At the end of the switching stroke S _Schalt , the button 11 is switched off by a switching pulse to the relevant system or by giving the button 11 a switching pulse. In view of this, the switching point SP is located in the region of the second force inflection point corresponding to the switching force/key force F _B of the button 11 . Subsequently, the force travel measurement is still carried out until the rated test force/maximum force F _max is reached by the force measuring device 14 , which is in particular a force sensor or a force measuring cell. In the illustrated embodiment, such a force-displacement curve is formed. The key 11 comprises an element biased from the inside, such as a spring plate. Once the bias element is pressed, the switching force F _B triggers the switching pulse, so that the user presses At this time, a click pulse is detected in the region of the first force inflection point of the actuating force F _O , or this gives the user a good switch tactile feel before pressing the switch further.

After the measurement and determination of the force-displacement curve has been carried out by the measuring system 6 , the contact between the support element and the support seat of the stabilizing unit is then released. In the embodiment shown in FIG. 2 , this is achieved by means of a currentless mode of the electromagnet 18 . Subsequently, the test object 7 can be removed from the holding device 4 . Subsequently, the aforementioned method for determining force-displacement curves in tactile test measurements can be carried out again from scratch. In addition to contacting the support element with the support seat by a non-positive connection, contact can also be achieved by a form-fit and/or non-positive connection.

While only preferred embodiments of the invention have been described and illustrated herein, it will be apparent to those skilled in the art that various modifications can be made without departing from the spirit and scope of the invention.

List of reference signs

1 Tactile test measuring device SP switch point

2 robots

3 Multi-axis arm S _Schalt switch travel

4 Holding device S _Start initial stroke

5 Measuring head F _O Operating force (Operating Force)

6 Measuring system F _max maximum force/rated test force

7 Test object F _B switch force/key force

8 support seat

9 Support elements

10 Bottom plate

11 buttons

12 Test Movement

13 Measuring head movement

14 force measuring device

15 test body

16 propulsion element

17 Travel measuring device

18 magnets

19 Magnetic components

20 rod elements

21 fasteners

22 Connection elements

23 Test object housing

24 end element

25 Housing

26 Gripping elements

27 flexible elements

Claims (13)

1. a kind of tactile test measuring apparatus (1), includes at least：

Holding meanss (4), be used to accommodating test object (7) and

Robot (2), with executor (3) and executing agency,

Wherein, the executing agency includes at least one measurement head (5), carries measuring system (6),

It is characterized in that,

The tactile tests measuring apparatus (1) including stablizing unit,

Wherein, the stable unit includes support component (9) and support base (8),

Wherein, by the stable unit, the measurement head (5) can be relative to the holding meanss (4) fixed to fixed bit It puts.

2. tactile test measuring apparatus (1) according to claim 1, which is characterized in that the measurement head (5) is including described Support component (9) or the support component (9) are disposed in the measurement head (5).

3. tactile according to claim 1 or 2 test measuring apparatus (1), which is characterized in that the holding meanss (4) or Bottom plate (10) is disposed in the holding meanss (4) or the bottom plate including the support base (8) or the support base (8) (10) on.

4. tactile test measuring apparatus (1) according to claim 1, which is characterized in that the measurement head (5) is including described Support base (8) or the support base (8) are disposed in the measurement head (5).

5. according to claim 1 or 4 tactile test measuring apparatus (1), which is characterized in that the holding meanss (4) or The bottom plate (10) including the support component (9) or the support component (9) be disposed in the holding meanss (4) or On the bottom plate (10).

6. tactile test measuring apparatus (1) according to any one of the preceding claims, which is characterized in that the support member Part (9) includes magnet (18), and the support base (8) includes magnetic element (19).

7. tactile test measuring apparatus (1) according to claim 4, which is characterized in that the magnet (18) is electromagnet, And the magnetic element (19) is ferromagnetic base or ferromagnetic base element.

8. tactile test measuring apparatus (1) according to any one of the preceding claims, which is characterized in that the support base (8) including receiving portion (5), the support component (9) that is used to accommodating and feel relieved in form-fit manner is configured to shape The end component (24) of cooperation.

9. tactile test measuring apparatus (1) according to any one of the preceding claims, which is characterized in that the support member Part (9) includes adjustable rod element (20).

10. tactile test measuring apparatus (1) according to any one of the preceding claims, which is characterized in that the support Element (9) temporary at least partly can be hardened.

11. tactile test measuring apparatus (1) according to any one of the preceding claims, which is characterized in that the measurement System (6) is the push rod system for determining force-displacement curve, is filled including at least one propulsion element (16), stroke measurment Put (17), device for measuring force (14) and test body (15).

12. a kind of measured in tactile test measures really using tactile according to any one of claim 1 to 11 test Determine the method for force-displacement curve, which is characterized in that this method includes the following steps：

Test object is inserted into holding meanss；

The measurement head with measuring system is made to shift to test object；

Support component is made to be contacted with stablizing the support base of unit；

By stablizing unit, measurement head is made to be fixed relative to holding meanss and test object position；

By measuring system, perform the measurement of force-displacement curve and determine；

Support component is discharged with stablizing unit and support base contact；

Test object is removed from holding meanss.

13. the method according to claim 12 that force-displacement curve is determined in tactile test measures, which is characterized in that Support component contact with the support base includes shape cooperation and/or electromagnetically force-fitting.