Device for determining forces acting on an object in at least three spatial directions

Abstract

To determine, in at least three spatial directions (Fx, Fy, Fz, Mx, My, Mz), a force acting on a manipulator.SOLUTION: The device comprises: two actuating elements (20a, 20b), where each of the actuating elements has an operating element (22a, 22b) with a longitudinal axis (L1, L2), and is movable, in particular tiltable, relative to a base element (24a, 24b), an individual force (F1, F2) can be determined, in at least three spatial directions, from the relative movement of the operating element and the base element, and the two actuating elements are arranged relative to one another such that the two operating elements are arranged on sides (25a, 25b) of the base elements facing away from one another; and an evaluation / control unit (30), which detects the individual force (F1, F2) determined by each operating element, and which is designed to calculate, in the at least three spatial directions, the force acting on the object from the two individual forces, in particular, from the sum of the individual forces.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a device for determining forces acting on an object in at least three spatial directions, and to an object equipped with such a device. [Background technology]

[0002] For programming and setting up movements of objects, in particular manipulators such as industrial robots or cobots, it is necessary to move these objects manually by applying forces to the object itself or to corresponding input devices on the object. In many applications, the sensitivity or agility of the respective input devices for performing the movements is then a limiting factor. Furthermore, current solutions have a sensitivity that depends on the position of the object due to the measurement principle of detecting the force.

[0003] Manipulators often have many degrees of freedom, all six (X, Y, Z, Ry, Ry, Rz), and simultaneous control of all these axes with interpolated Cartesian motion is crucial to making the programming process fast and intuitive. Summary of the Invention [Problem to be solved by the invention]

[0004] It is currently known to measure the motor currents required for the movement of each axis of an object, especially a manipulator, and from this calculate the torque at each axis. By subtracting the required holding torque, the change caused by the force applied to the axis can be calculated and converted into a subsequent movement. However, this has the disadvantage that the force introduced into the object is only measured indirectly. Depending on the position of the object, especially the manipulator, leverage effects of different magnitudes can occur, which causes the sensitivity of the solution to be distributed unevenly throughout the workspace.

[0005] Alternatively, it is known to directly measure the torque of each axis by means of a torque sensor mounted on the axis and to convert the change in torque caused by a force applied to the axis into a subsequent motion. However, this method also has the disadvantage that the force introduced into the object is only measured indirectly and that leverage effects of varying magnitudes can occur depending on the position of the object, particularly the manipulator. Furthermore, it is necessary to mount a torque sensor on each axis, which can lead to high costs.

[0006] The object of the present invention is to provide a device for determining forces acting on an object in at least three spatial directions, which device makes it possible to detect forces introduced into an object, thereby making it possible to simply perform a learning or programming process for the object. [Means for solving the problem]

[0007] The object of the present invention is achieved by a device for determining forces acting on an object in at least three spatial directions, having the features of claim 1 . Advantageous embodiments and developments of the invention are set forth in the dependent claims.

[0008] An apparatus according to the present invention for determining forces acting on an object, particularly a manipulator, in at least three spatial directions comprises two actuating elements, each of which has an operating element with a longitudinal axis, the operating elements being movable, particularly tiltable, relative to a base element, such that individual forces can be determined in at least three spatial directions from the relative movement between the operating elements and the base element, the two operating elements being arranged relative to one another such that the two operating elements are arranged on opposing faces of the base element, and the apparatus further comprises an evaluation / control unit designed to detect the individual forces determined by each actuating element and to calculate the forces acting on the object in at least three spatial directions from the two individual forces, particularly from the sum of the individual forces. Operation of such actuating elements can be performed intuitively. By arranging the operating elements on opposing faces of the base element, a user can grasp the operating elements, for example, by placing their thumb on one of the operating elements and their index finger on the other. In this way, a user can simply grasp the apparatus, move it in space, and perform teaching or programming processes on an object.

[0009] The forces acting on an object can be calculated in particular in at least three linear spatial directions X, Y, Z. Advantageously, from the relative movement between the operating element and the base element, individual forces can be determined in at least four spatial directions, in particular in three linear spatial directions and in a direction of rotation about the longitudinal axis of the operating element, which corresponds to a torque acting about the longitudinal axis of the operating element, thereby increasing the accuracy of determining the forces acting on the object.

[0010] Advantageously, in order to further increase the accuracy of determining the force acting on the object, the evaluation / control unit is designed to calculate the force acting on the object in six spatial directions from two individual forces, in particular from the sum of the individual forces.

[0011] Preferably, the two base elements are arranged at a distance A from each other, which allows the forces acting on the object to be determined in six spatial directions, even if the two individual forces are determined in fewer spatial directions.

[0012] According to a preferred development of the invention, each of the actuating elements has an operating element with a longitudinal axis that is tiltable relative to the base element, the tilting movement being detectable simply and with high precision, while being intuitively executable by the user, resulting in an overall simple operation.

[0013] Preferably, the actuation elements are designed like a joystick or trackpoint, which may allow for easy and intuitive handling. According to a preferred embodiment of the invention, the evaluation and control unit is provided to calculate the force acting between the two actuating elements in at least three spatial directions based on the individual forces, in particular from the difference between the individual forces. Further determination of the force acting between the two actuating elements allows further applications.

[0014] In particular, in a preferred development, the device can have a deadman switch that switches depending on the force acting between the two actuating elements, for example, the force acting between the two actuating elements can be compared with a target value, and if it is exceeded or fallen short, a certain event can be triggered, such as for example blocking the movement of the object or activating a learning or programming process.

[0015] This allows a single device to both control the movement of an object based on determining the force acting on the object and simultaneously provide a deadman's switch based on determining the force acting between two actuating elements, both of which can be operated by a user with one hand.

[0016] According to a preferred embodiment of the invention, the actuation element, in particular the operating element, is coupled to an actuator, in particular a vibration motor. Such an actuator allows, for example, haptic feedback to the user regarding the actuation performed, the limitation of the object's movement, or the limitation of the force or input, i.e., for example, to warn the user that he is applying too much force or torque or that he cannot move the object faster. In principle, it is then also possible to provide different haptic feedback patterns in order to feed back different information to the user.

[0017] The object according to the invention, in particular a manipulator, preferably an industrial robot or cobot, is equipped with the device according to the invention as described above. Industrial robots that work together with humans and are not separated from them by protective devices in the production process are called cobots or collaborative robots. Therefore, in particular cobots are provided with appropriate safety functions that allow the cobot to interact safely with the user.

[0018] Preferably, the two actuating elements are arranged relative to each other on the surface of the object such that the longitudinal axes of the actuating elements are arranged parallel to each other, which simplifies the evaluation of the individual forces.

[0019] An advantageous development of the invention provides that the device is removably arranged on the object, in particular in the form of a module, so that it can be easily retrofitted. Preferably, the two actuation elements are arranged on two opposite sides of the surface of the object to allow for an ergonomic grip by the user.

[0020] The embodiments of the present invention will be described in detail with reference to the following figures. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a perspective view of an exemplary embodiment of a device according to the invention for determining forces acting on an object in at least three spatial directions; [Figure 2] FIG. 2 is a top view of the device according to FIG. 1. [Figure 3] 2 is a perspective view of the device according to FIG. 1 when placed in a tool receptacle for a robot. [Figure 4] FIG. 4 is a top view of the arrangement according to FIG. [Figure 5] FIG. 2 is a perspective view of a part of a robot arm in which the device according to FIG. 1 is arranged. [Figure 6] FIG. 6 is another perspective view of a portion of the robot arm according to FIG. 5. [Figure 7] 1 is a perspective view of a portion of a robot arm incorporating a device for determining forces acting on an object in at least three spatial directions; [Figure 8] FIG. 8 is another perspective view of a portion of the robot arm according to FIG. 7. DETAILED DESCRIPTION OF THE INVENTION

[0022] In all figures, the same reference numbers indicate the same or functionally similar parts, but for clarity, not all reference numbers are shown in all figures. 1 and 2 show an exemplary embodiment of an apparatus 10 for determining forces acting on an object in at least three spatial directions Fx, Fy, Fz, Mx, My, and Mz. The spatial directions are the three linear directions X, Y, and Z and rotations about these three linear directions. If the forces acting on the object are determined in three spatial directions, they are in particular the three linear directions X, Y, and Z. Preferably, the forces acting on the object are determined in all six spatial directions Fx, Fy, Fz, Mx, My, and Mz, i.e., the linear forces Fx, Fy, and Fz in the three directions X, Y, and Z and the torques My, My, and Mz about these three axes.

[0023] The device includes two actuating elements 20a, 20b, each of which has an operating element 22a, 22b with longitudinal axes L1, L2, which are movable, particularly tiltable, relative to base elements 24a, 24b. For example, each of the actuating elements 20a, 20b can be designed like a joystick or trackpoint. Each base element 24a, 24b has a first surface 25a, 25b and a second surface 26a arranged substantially parallel thereto, the second surface of the second base element 20b being hidden in the figure. The operating elements 22a, 22b are particularly arranged on the first surfaces 25a, 25b. The two actuating elements 20a, 20b are particularly designed to have the same structure.

[0024] According to the invention, the two actuating elements 20a, 20b are connected to the two operating elements 2 2 a, 2 2 The two actuating elements 20a, 20b are arranged relative to one another such that the first and second faces 25a, 25b of the base elements 24a, 24b are located on opposite faces 25a, 25b of the base elements 24a, 24b. The other two faces 26a of the base elements 24a, 24b are particularly arranged facing one another. The two actuating elements 20a, 20b are particularly arranged at a distance A from one another.

[0025] The actuating elements 20a, 20b are in particular two operating elements 2 2 a, 2 2 b are arranged relative to one another so that their longitudinal axes L1, L2 are parallel to one another and in particular coincide (see FIG. 2).

[0026] Actuating elements 20a, 20b, in particular operating element 2 2 a, 2 2 b is the operating element 2 when activated by the user; 2 a, 2 2 In order to be able to give haptic feedback to b, it may be coupled to an actuator (not shown), in particular a vibration motor.

[0027] For each of the actuating elements 20a, 20b, there is an operating element 22a, 22b and a base element 24a, 24b. band the relative movement between the operating element 2 and the actuator 3 generates respective forces F1, F2 in at least three spatial directions, in particular in at least three linear spatial directions X, Y, Z, and preferably also in the operating element 2. 2 a, 2 2 b and the direction of rotation Mz around the longitudinal axes L1 and L2.

[0028] The device 10 further comprises an evaluation / control unit 30 designed to detect the individual forces F1, F2 determined by each actuating element 20a, 20b and to calculate from the two individual forces F1, F2 the force acting on the object in at least three spatial directions, in particular in the three linear spatial directions Fx, Fy, Fz, but preferably in all six spatial directions Fx, Fy, Fz, Mx, My, Mz. This calculation can be performed, for example, from the sum of the individual forces F1, F2, in particular taking into account the distance A between the two actuating elements 20a, 20b. Even if the individual actuating elements 20a, 20b determine the individual forces F1, F2 in fewer than six spatial directions, the fact that two actuating elements 20a, 20b are used and are arranged at a distance from each other allows the calculation of the force F acting on the object as a whole to be performed in all six spatial directions Fx, Fy, Fz, Mx, My, Mz.

[0029] The evaluation / control unit can further be designed to calculate the force acting between the two actuating elements 20a, 20b in at least three spatial directions, preferably all six spatial directions Fx, Fy, Fz, Mx, My, and M, based on the individual forces F1, F2, particularly the difference between the individual forces F1, F2, and also taking into account the distance A between the actuating elements 20a, 20b. The force acting between the two actuating elements 20a, 20b can then be used, for example, to switch the deadman's switch 40. The deadman's switch 40 can then detect, for example, whether a user is touching the actuating elements 20a, 20b and only then initiate a learning or programming process. If the pressure is too low or too high, the deadman's switch 40 can stop or prevent the movement of the object.

[0030] The actuation elements 20a, 20b and the evaluation and control unit 30 can be arranged in a housing 50 that can be removably arranged on the object. In that case, the operating elements 22a, 22b are accessible from outside the housing 50 to enable operation. In that case, the operating elements 22a, 22b are arranged in particular on two opposite faces 51, 52 of the surface of the housing 50. The housing 50 can be attached using fastening devices such as screws, magnets, snap connections, etc.

[0031] Figures 3 and 4 show the arrangement of the device 10 in a tool receiving section 60, which may be arranged, for example, in the robot head 72 of a robot arm 70, as shown in Figures 5 and 6. The robot arm 70 may be an industrial robot or a collaborative robot, a so-called cobot robot arm 70.

[0032] Since the device 10 is able to determine the forces acting on the robot arm 70 applied by the user and convert them into control signals in order to enable the movement to be automatically followed after the teaching process, using such a device 10 allows the user to simply teach the movement of the robot arm 70 by gripping the area of ​​the free end of the robot arm 70, in particular the robot head 72, and in particular the tool receptacle 60 therein, and guiding the robot arm 70 in the desired direction.

[0033] 7 and 8 differs from the previous embodiment only in that the device 10 is not removably arranged in the tool receiving portion 60, but is instead integrated into the tool holder 60, i.e., arranged in the same housing. Alternatively, the device 10 could be integrated into the robot head 72 or elsewhere on the robot arm 70, in which case it would be preferable to place the device 10 as far as possible from the axis of rotation or pivot of the robot arm 70, in order to allow a longer lever to reduce the force required to move the robot arm 70. [Explanation of symbols]

[0034] 10...device 20a...operating element 20b...Operating element 22a...operation element 22b…operation element 24a...bass element 24b...bass element 25a...side 25b...side 26a…side 30...Evaluation / control unit 40...Deadman's Switch 50…Housing 60...Tool storage section 70...Robot arm 72...Robot head A...Distance L1...longitudinal axis L2...longitudinal axis

Claims

1. A device (10) for determining forces acting on an object in at least three spatial directions (Fx, Fy, Fz, Mx, My, Mz), comprising: two actuating elements (20a, 20b), each having an operating element (22a, 22b) with a longitudinal axis (L1, L2), the operating elements being movable relative to a base element (24a, 24b), such that respective forces (F1, F2) can be determined in at least three spatial directions from the relative movement between the operating elements (22a, 22b) and the base element (24a, 24b), the two actuating elements (20a, 20b) being arranged relative to one another such that the two operating elements (22a, 22b) are arranged on opposite faces (25a, 25b) of the base element (24a, 24b); an evaluation and control unit (30) designed to detect the individual forces (F1, F2) determined by each actuation element (20a, 20b) and to calculate the forces acting on the object from the two individual forces (F1, F2) in at least three spatial directions (Fx, Fy, Fz, Mx, My, Mz), Apparatus (10).

2. characterised in that individual forces (F1, F2) can be determined in at least four spatial directions (Fx, Fy, Fz, Mx, My, Mz) from the relative movement between the operating elements (22a, 22b) and the base elements (24a, 24b), 10. The apparatus of claim 1.

3. characterised in that the evaluation and control unit (30) is designed to calculate the forces acting on the object in six spatial directions (Fx, Fy, Fz, Mx, My, Mz) from the two individual forces (F1, F2), 10. The apparatus of claim 1.

4. the two base elements (24a, 24b) are arranged at a distance (A) from each other, 10. The apparatus of claim 1.

5. characterised in that the actuating elements (20a, 20b) are designed like a joystick or a trackpoint, 10. The apparatus of claim 1.

6. the evaluation / control unit (30) is designed to calculate the forces acting between the two actuating elements (20a, 20b) in at least three spatial directions (Fx, Fy, Fz, Mx, My, Mz) based on the individual forces (F1, F2), 10. The apparatus of claim 1.

7. The device (10) is characterized in that it has a deadman switch (40) that switches depending on the force acting between the two actuating elements (20a, 20b).

10. The apparatus of claim 1.

8. the actuating elements (20a, 20b) are coupled to actuators, 10. The apparatus of claim 1.

9. An object comprising a device (10) according to any one of claims 1 to 8.

10. the two actuating elements (20a, 20b) are arranged relative to each other on the surface of the object such that the longitudinal axes (L1, L2) of the actuating elements are arranged parallel to each other, 10. The object of claim 9.

11. The device (10) is detachably arranged on the object, 10. The object of claim 9.

12. the two actuating elements (20a, 20b) are arranged on two opposite sides of the surface of the object, 10. The object of claim 9.

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