DEVICE FOR DETERMINING A FORCE ACTING ON A BODY IN AT LEAST THREE SPATIAL DIRECTIONS

Description

[0001] The invention relates to a device for determining a force acting on a body in at least three spatial directions and to a body with such a device.

[0002] Programming and setting up manipulators, especially industrial robots or cobots, requires manual movement of these manipulators by applying force to the manipulator itself or to a corresponding input device attached to the manipulator. In many applications, the sensitivity of the input device is a limiting factor in executing the movement. Furthermore, current solutions, due to their force measurement principles, exhibit sensitivity that depends on the manipulator's position.

[0003] Since manipulators often have multiple degrees of freedom, the simultaneous control of all these axes in interpolated Cartesian movements in all six degrees of freedom (X, Y, Z, Ry, Ry, Rz) is of great importance to make the programming process fast and intuitive.

[0004] It is currently known to measure the motor currents required to move individual axes of a body, particularly a manipulator, and to calculate the torques acting on each axis. By subtracting the required holding torques, changes resulting from forces applied to the axes can be calculated and converted into subsequent movements. However, a disadvantage of this method is that the forces applied to the body are only measured indirectly. Depending on the position of the body, especially the manipulator, varying leverage effects can occur, resulting in an uneven distribution of the solution's sensitivity across the working space.

[0005] Alternatively, it is also known to directly measure the torques on the respective axes using torque sensors integrated into the axes and to translate changes in torque caused by forces applied to the axes into subsequent movements. However, a disadvantage of this method is that the forces applied to the body are only measured indirectly, and depending on the position of the body, especially the manipulator, different leverage effects can occur. Furthermore, torque sensors must be installed on each axis, which can lead to high costs.

[0006] Document JP H06 179187 A (MITSUBISHI HEAVY IND LTD) June 28, 1994 (1994-06-28) discloses an orientation-capturing teaching mechanism that will improve the intuitiveness of the operating instructions through a teaching unit of a robot manipulator.

[0007] WO 2007 / 039785 A1 (ABB AS [NO]; BRAUT KNUT [NO]) 12 April 2007 (2007-04-12) discloses an example of a robot controller intended for an industrial robot.

[0008] US 2020 / 253677 A1 (JINNO MAKOTO [JP]) August 13, 2020 (2020-08-13) reveals an example of a manipulator and surgical support robot system.

[0009] The object of the invention is to provide a device for determining a force acting on a body in at least three spatial directions, by means of which the forces applied to the body can be detected in such a way that a learning or programming process of the body is made possible in a simple manner.

[0010] The object of the invention is solved by a device for determining a force acting on a body in at least three spatial directions with the features of the patent claim. 1.

[0011] Advantageous embodiments and further developments of the invention are specified in the dependent claims.

[0012] The device according to the invention for determining a force acting on a body, in particular a manipulator, in at least three spatial directions has two actuating elements, each of which has a control element with a longitudinal axis which is movable, in particular tiltable, relative to a base element, wherein an individual force in at least three spatial directions can be determined from the relative movement between the control element and the base element, and wherein the two actuating elements are arranged relative to each other such that the two control elements are arranged on opposite sides of the base elements, and further comprises an evaluation / control unit which detects the individual force determined by each actuating element and which is configured to calculate the force acting on the body in at least three spatial directions from the two individual forces, in particular from the sum of the individual forces.Operating such control elements can be intuitive. Because the controls are arranged on opposite sides of the base elements, a user can grip them in such a way that their thumb rests on one control and, for example, their index finger on the other. In this way, the user can move the device in space simply by touching it and perform a learning or programming process directly on their body.

[0013] The force acting on the body can be expressed in particular at least in the three linear spatial directions. X, Y, Z can be calculated.

[0014] Advantageously, a single force can be determined from the relative movement between the control element and the base element in at least four spatial directions, in particular in the three linear spatial directions and in the direction of rotation about the longitudinal axis of the control element, corresponding to the torque acting about the longitudinal axis of the control element, which increases the accuracy of the determination of the force acting on the body.

[0015] Advantageously, the evaluation / control unit is designed to calculate the force acting on the body in six spatial directions from the two individual forces, in particular from the sum of the individual forces, in order to further increase the accuracy of the determination of the force acting on the body.

[0016] Preferably, the two base elements are arranged at a distance A from each other, which makes it possible to determine the force acting on the body in six spatial directions, even if the two individual forces are determined in fewer spatial directions.

[0017] According to a preferred embodiment of the invention, each of the actuating elements has a control element with a longitudinal axis, which is tiltable relative to a base element. The tilting movements can be detected easily and with high accuracy, while at the same time the tilting movements can be performed intuitively by a user, resulting in overall simple operation.

[0018] Advantageously, the operating elements are designed in the style of a joystick or trackpoint, which allows for simple and intuitive handling.

[0019] According to a preferred embodiment of the invention, the evaluation / control unit is designed 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. The additional determination of the force acting between the two actuating elements enables further applications.

[0020] In a preferred embodiment, the device can include a dead man's 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 setpoint values, and if these values ​​are exceeded or not reached, certain events can be triggered, such as preventing movement of the body or activating a learning or programming process.

[0021] In one device, both the control of a body's movement based on the determination of the force acting on the body and simultaneously a dead man's switch based on the determination of the force acting between the two actuating elements can be realized, both of which can be operated with a single hand of the user.

[0022] According to a preferred embodiment of the invention, the actuating element, in particular the control element, is coupled to an actuator, in particular a vibration motor. Such an actuator enables haptic feedback to the user, for example, regarding successful actuation, the body's movement limits, or force or input limits, i.e., for example, an indication that the user is exerting too much force or torque or that the body can no longer move faster. It is also possible, in principle, to provide different haptic feedback patterns in order to convey different information to the user.

[0023] A body according to the invention, in particular a manipulator, preferably an industrial robot or cobot, is equipped with a device according to the invention as described above. A cobot or collaborative robot is an industrial robot that works alongside humans and is not separated from them by protective devices in the production process. Therefore, especially in the case of cobots, appropriate safety functions are provided to ensure safe interaction between the cobot and the user.

[0024] Preferably, the two actuating elements are arranged relative to each other on the surface of the body such that their longitudinal axes are parallel to each other. This can simplify the evaluation of the individual forces.

[0025] An advantageous embodiment of the invention provides that the device is detachably arranged on the body, particularly in the form of a module. This allows for easy retrofitting.

[0026] Preferably, the two actuating elements are arranged on two opposite sides of the body's surface to allow for ergonomic gripping by a user.

[0027] Exemplary embodiments of the invention are explained in detail with reference to the following figures. They show Fig. 1 a perspective view of an embodiment of a device according to the invention for determining a force acting on a body in at least three spatial directions, Fig. 2 a top view of the device according to Figure 1 , Fig. 3 a perspective view of the device according to Figure 1When arranged on a tool holder for a robot, Fig. 4 shows a top view of the arrangement according to Fig. 3 , Fig. 5 a perspective view of part of a robot arm with a device attached to it according to Fig. 1 , Fig. 6 another perspective view of the part of the robot arm according to Fig. 5 Fig. 7 is a perspective view of part of a robot arm with an integrated device for determining a force acting on a body in at least three spatial directions, and Fig. 8 is another perspective view of the part of the robot arm according to Fig. 7 .

[0028] In all figures, the same reference symbols denote identical or functionally equivalent parts, although for the sake of clarity not all reference symbols are shown in all figures.

[0029] The Figures 1 and 2Figure 10 shows an embodiment of a device for determining a force acting on a body in at least three spatial directions Fx, Fy, Fz, Mx, My, Mz. These spatial directions are the three linear directions X, Y, Z and the rotation about these three linear directions. If the force acting on a body is determined in three spatial directions, these are in particular the three linear directions X, Y, Z. Preferably, the force acting on the body is determined in all six spatial directions Fx, Fy, Fz, Mx, My, Mz, that is, the linear forces Fx, Fy, Fz in the three directions X, Y, and Z, as well as the torques My, My, Mz about these three axes.

[0030] The device comprises two actuating elements 20a, 20b, each of which has a control element 22a, 22b with a longitudinal axis L1, L2, which is movable, in particular tiltable, relative to a base element 24a, 24b. For example, each of the actuating elements 20a, 20b can be configured as a joystick or trackpoint. Each base element 24a, 24b has a first side 25a, 25b and a second side 26a arranged substantially parallel thereto, the second side of the second base element 20b being hidden in the figures. The control element 22a, 22b is in particular arranged on the first side 25a, 25b. The two actuating elements 20a, 20b are in particular identical construction.

[0031] According to the invention, the two actuating elements 20a, 20b are arranged relative to each other such that the two operating elements 24a, 24b are arranged on opposite sides 25a, 25b of the base elements 24a, 24b. The two other sides 26a of the base elements 24a, 24b are arranged facing each other. The two actuating elements 20a, 20b are arranged at a distance A from each other.

[0032] The actuating elements 20a, 20b are arranged in such a way as to the longitudinal axes L1, L2 of the two operating elements 24a, 24b are arranged parallel to each other and in particular coincide (cf. Fig. 2 ).

[0033] The actuating element 20a, 20b, in particular the control element 24a, 24b, can be coupled with an actuator (not shown), in particular a vibration motor, in order to provide haptic feedback on the control element 24a, 24b when actuated by a user.

[0034] For each of the actuating elements 20a, 20b, a single force F1, F2 can be determined from the relative movement between the operating element 22a, 22b and the base element 24a, 24n in at least three spatial directions, in particular at least in the three linear spatial directions X, Y, Z, preferably additionally in the direction of the rotation Mz about the longitudinal axis L1, L2 of the operating element 24a, 24b.

[0035] The device 10 further comprises an evaluation / control unit 30, which detects the individual forces F1, F2 determined by each actuating element 20a, 20b and which is configured to calculate the force acting on the body in at least three spatial directions, in particular the three linear spatial directions Fx, Fy, Fz, but preferably in all six spatial directions Fx, Fy, Fz, Mx, My, Mz, from the two individual forces F1, F2. The 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 each individual actuating element 20a, 20b determines a single force F1, F2 in fewer than six spatial directions, due to the fact that two actuating elements 20a, 20b are used and these are spaced apart from each other, a calculation of the force F acting on the body can also be carried out in all six spatial directions Fx, Fy, Fz, Mx, My, Mz.

[0036] The evaluation / control unit can further be configured to calculate the force acting between the two actuating elements 20a, 20b in at least three spatial directions, preferably in all six spatial directions (Fx, Fy, Fz, Mx, My, M), based on the individual forces F1, F2, in particular from the difference between the individual forces F1, F2, also taking into account the distance A between the actuating elements 20a, 20b. The force acting between the two actuating elements 20a, 20b can, for example, be used to switch a dead man's switch 40. The dead man's switch 40 can, for example, be used to detect whether a user is touching the actuating elements 20a, 20b and only in this case activate a learning process or a programming process. If the pressure is too low or too high, the dead man's switch 40 can stop or prevent movement of the body.

[0037] The actuating elements 20a, 20b and the evaluation / control unit 30 can be arranged in a housing 50, which can be detachably mounted on a body. The operating elements 22a, 22b are accessible from outside the housing 50 to allow operation. The operating elements 22a, 22b are arranged, in particular, on two opposite sides 51, 52 of the surface of the housing 50. The housing 50 can be fastened by means of a fastening device such as screws, magnets, snap-fit ​​connections, or similar.

[0038] The Figures 3 and 4 show an arrangement of the device 10 on a tool holder 60, which, for example, as in the Figures 5 and 6 The robot head 72 can be arranged on a robot arm 70. The robot arm 70 can be the arm of an industrial robot or a collaborative robot, a so-called cobot.

[0039] With such a device 10, a user is enabled to easily teach a movement of the robot arm 70 by grasping in the area of ​​the free end of the robot arm 70, in particular at the robot head 72, there especially at the tool holder 60, and guiding the robot arm 70 in the desired directions, since the device 10 determines the force applied by the user and acting on the robot arm 70 and can convert it into control signals after the teaching process in order to be able to automatically replicate the movement.

[0040] The in the Figures 7 and 8The illustrated embodiment differs from the previously described embodiment only in that the device 10 is not detachably arranged on the tool holder 60, but is integrated into the tool holder 60, i.e., arranged in the same housing. Alternatively, it would also be possible to integrate the device 10 into the robot head 72 or at another location on the robot arm 70. An arrangement of the device 10 at the greatest possible distance from the rotational or pivoting axes of the robot arm 70 is preferred in order to minimize the forces required to move the robot arm 70 due to the longer lever arm. Reference symbol list

[0041] 10 Device 20a Actuating element 20b Actuating element 22a Operating element 22b Operating element 24a Base element 24b Base element 25a Side 25b Side 26a Side 30 Evaluation / Control unit 40 Dead man's switch 50 Housing 60 Tool holder 70 Robot arm 72 Robot head A Distance L1 Longitudinal axis L2 Longitudinal axis

Claims

1. Device (10) for determining a force acting on a body, in particular a manipulator, in at least three spatial directions (Fx, Fy, Fz, Mx, My, Mz), comprising - two actuation elements (20a, 20b), wherein each of the actuation elements (20a, 20b) comprises an operating element (22a, 22b) having a longitudinal axis (L1, L2), which is movable, in particular tiltable, relative to a base element (24a, 24b), wherein a single force (F1, F2) in at least three spatial directions can be determined from the relative movement between the operating element (22a, 22b) and the base element (24a, 24b), and wherein the two actuation elements (20a, 20b) are arranged relative to one another in such a way that the two operating elements (22a, 22b) are arranged on sides (25a, 25b) of the base element (24a, 24b) facing away from one another, - and an evaluation / control unit (30) which acquires the single force (F1, F2) determined from each actuation element (20a, 20b) and which is configured for calculating the force acting on the body in at least three spatial directions (Fx, Fy, Fz, Mx, My, Mz) from the two single forces (F1, F2), in particular from the sum of the single forces.

2. Device according to claim 1, characterised in that a single force (F1, F2) in at least four spatial directions (Fx, Fy, Fz, Mx, My, Mz), in particular in the three linear spatial directions and in the direction of the rotation about the longitudinal axis (L1, L2) of the operating element (22a, 22b), can be determined from the relative movement between the operating element (22a, 22b) and the base element (24a, 24b).

3. Device according to either of the preceding claims, characterised in that the evaluation / control unit (30) is configured to calculate the force acting on the body in six spatial directions (Fx, Fy, Fz, Mx, My, Mz) from the two single forces (F1, F1), in particular from the sum of the single forces.

4. Device according to any of the preceding claims, characterised in that the two base elements (24a, 24b) are arranged at a spacing (A) from one another.

5. Device according to any of the preceding claims, characterised in that the actuation elements (20a, 20b) are configured in the manner of a joystick or trackpoint.

6. Device according to any of the preceding claims, characterised in that the evaluation / control unit (30) is configured to calculate the force acting between the two actuation elements (20a, 20b) in at least three spatial directions (Fx, Fy, Fz, Mx, My, Mz) on the basis of the single forces (F1, F2), in particular from the difference of the single forces.

7. Device according to any of the preceding claims, characterised in that the device (10) comprises a dead man's switch (40) which switches depending on the force acting between the two actuation elements (20a, 20b).

8. Device according to any of the preceding claims, characterised in that the actuation element (20a, 20b), in particular the operating element (22a, 22b), is coupled to an actuator, in particular a vibrating motor.

9. Body, in particular manipulator, preferably industrial robot or cobot, comprising a device (10) according to any of the preceding claims.

10. Body according to claim 9, characterised in that the two actuation elements (20a, 20b) are arranged relative to one another, on the surface of the body, in such a way that their longitudinal axes (L1, L2) are arranged in parallel with one another.

11. Body according to either claim 9 or claim 10, characterised in that the device (10) is releasably arranged on the body.

12. Body according to any of claims 9 to 11, characterised in that the two actuation elements (20a, 20b) are arranged on two sides of the surface of the body facing away from one another.