Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
  • G01L5/22—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the force applied to control members, e.g. control members of vehicles, triggers
  • G01L5/226—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the force applied to control members, e.g. control members of vehicles, triggers to manipulators, e.g. the force due to gripping
  • G01L5/228—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the force applied to control members, e.g. control members of vehicles, triggers to manipulators, e.g. the force due to gripping using tactile array force sensors
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
  • G01L5/16—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring several components of force
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J13/00—Controls for manipulators
  • B25J13/08—Controls for manipulators by means of sensing devices, e.g. viewing or touching devices
  • B25J13/085—Force or torque sensors
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Programme-controlled manipulators
  • B25J9/16—Programme controls
  • B25J9/1628—Programme controls characterised by the control loop
  • B25J9/1633—Programme controls characterised by the control loop compliant, force, torque control, e.g. combined with position control
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01L—MEASURING FORCE, STRESS, TORQUE, WORK, MECHANICAL POWER, MECHANICAL EFFICIENCY, OR FLUID PRESSURE
  • G01L5/00—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes
  • G01L5/22—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the force applied to control members, e.g. control members of vehicles, triggers
  • G01L5/226—Apparatus for, or methods of, measuring force, work, mechanical power, or torque, specially adapted for specific purposes for measuring the force applied to control members, e.g. control members of vehicles, triggers to manipulators, e.g. the force due to gripping
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/40—Robotics, robotics mapping to robotics vision
  • G05B2219/40586—6-DOF force sensor

Definitions

• the invention relates to a device and a method for determining a force acting on a body in at least three spatial directions and a method for controlling the movement of a body.
• the object of the invention is therefore to provide a device and a method for determining a force acting on a body in at least three spatial directions and, in particular, based thereon, a method for controlling a body, by means of which the forces applied to the body can be recorded in such a way that that a learning or programming process of the body is made possible in a simple way.
• the object of the invention is achieved by a device for determining a force acting on a body in at least three spatial directions with the features of patent claim 1, a method for determining a force acting on a body in at least three spatial directions with the features of patent claim 13 and a Method for controlling the movement of a body with the features of patent claim 15.
• the device according to the invention for determining a force acting on a body, in particular a manipulator such as an industrial robot or a cobot, in at least three spatial directions has at least one sensor element for attachment to the surface of the body, which comprises at least three individual sensor elements, with each individual sensor element is designed to determine an individual force in one direction, or which comprises at least one individual sensor element, which is designed to determine an individual force in three spatial directions, and further comprises an evaluation/control unit, which detects the individual force determined by each individual sensor element and which is designed for this purpose is to calculate the force acting on the sensor element in at least three spatial directions by projecting the individual forces onto a virtual point of the sensor element.
• the sensor element is designed and suitable for being attached to the surface of the body, it is possible to directly measure the forces applied to the body, in particular directly at the point at which the force is applied. I'm exactly one Sensor element arranged on the surface of the body, the force acting on the sensor element corresponds to the force acting on the body.
• a single individual sensor element is sufficient.
• individual sensor elements which are designed to determine an individual force in one direction
• at least three individual sensor elements are arranged in one sensor element, with the directions in which the three individual sensor elements determine an individual force preferably being arranged perpendicular to one another in order to determine the To be able to allow force in three spatial directions in a simple way.
• Each sensor element preferably comprises a plurality of, preferably at least 15, particularly preferably at least 20, individual sensor elements, as a result of which the accuracy of the determination of the force acting on the sensor element can be increased.
• the individual sensor elements are advantageously arranged in a grid or a polar arrangement, which can simplify the determination of the force acting on the sensor element.
• the individual sensor elements of each sensor element have at least two groups of individual sensor elements, which can be evaluated independently of one another. This enables redundant evaluation in order to be able to meet safety requirements.
• the individual sensor elements of each group are preferably arranged in each case in a grid or a polar arrangement, with the grids or the polar arrangements preferably being arranged in an interlocking manner and being designed, for example, in the manner of a chess board. A particularly good redundancy can thereby be achieved.
• the device comprises at least two sensor elements, which are preferably arranged at a distance from one another, particularly preferably on two opposite sides of the surface of the body.
• the sensor elements can preferably be evaluated independently of one another, as a result of which further redundancy can be achieved.
• the sensor element has a cover that is freely mounted relative to the sensor element.
• a covering can enable the forces acting on the sensor element to be determined in six spatial directions.
• the sensor element is preferably made of a flexible material which can be applied to the body in particular in the manner of a skin.
• a flexible material also allows the sensor elements to be attached to complex body geometries. ria .
• the application in the manner of a skin has the advantage that the sensor elements can be arranged in a space-saving manner and, in addition, operation and handling can be simplified.
• a configuration of the sensor elements in the manner of an artificial, tactile skin enables an intuitive and rapid programming, set-up or learning process.
• the evaluation/control unit advantageously includes a controller into which the force acting on the body can be introduced as an actual value.
• the controller enables the applied force to be converted as well as possible into a corresponding subsequent movement of the body.
• a body according to the invention in particular a manipulator, preferably an industrial robot or cobot, has a device according to the invention, the at least one sensor element, preferably the at least two sensor elements, being arranged on the surface of the body. Attaching the sensor element to the surface of the body enables the force applied to be determined directly.
• the body can be moved manually in a simple manner for programming or for setting up or teaching in movements by touching the body and moving it in the desired directions by applying a force to the body itself.
• a large number of sensor elements are arranged on the surface of the body, these covering in particular a large part of the surface, preferably the entire surface, of the body, with the sensor elements preferably being made of a flexible material which, in particular, is Kind of a skin can be applied to the body. Is the surface of the body covered extensively with sensor elements, handling can be simplified and designed to be particularly intuitive.
• the method according to the invention for determining a force acting on a body in particular a manipulator, for example an industrial robot or cobot, in at least three spatial directions with at least one sensor element attached to the surface of the body, which comprises at least three individual sensor elements, with each individual sensor element for determining a Individual force is designed in one direction, or which comprises at least one individual sensor element, which is designed to determine an individual force in three spatial directions, and an evaluation/control unit, has the steps:
• Such a method enables a direct measurement of the forces applied to the body, at least in three spatial directions, in particular directly at the point at which the force is applied.
• At least two sensor elements are arranged on the surface of the body at a distance from one another, with the following steps being carried out:
• Such a method enables a direct measurement of the forces applied to the body in six spatial directions, ie the forces X, Y, Z and the torques Rx, Ry, Rz, in particular directly at the point at which the force is applied .
• the force acting on a body is advantageously determined independently of one another by means of two groups of individual sensor elements. This enables redundancy, which represents a safety function.
• the method according to the invention is preferably further developed into a method for controlling the movement of a body, in particular a manipulator, for example an industrial robot or commander, with the steps:
• Such a controller makes it possible, on the basis of an acting force that causes a deviation of the actual value of the force from the target value of the force, to movement of the body, especially in the direction of the acting force.
• Disturbance variables are advantageously taken into account in the controller, as a result of which the desired movement can be carried out even in the event of disturbances.
• the method according to the invention is preferably further developed into a method for controlling the movement of a body, in particular a manipulator, for example an industrial robot or commander, with the steps:
• Such a method enables a safety function such that the movement of the body is only carried out when certain conditions are met.
• safety-relevant release switches such as dead man's switches or confirmation switches can be implemented in this way.
• the method according to the invention is preferably further developed into a method for controlling the movement of a body, in particular a manipulator, for example an industrial robot or commander, with the steps:
• a method enables input and/or control commands to be entered into the evaluation/control unit.
• the patterns can have any force profile, for example tapping twice within a specified period of time, and can result in a pre-programmed command stored in the evaluation/control unit, for example saving the current position of the body, in particular the manipulator, or the operation Release accessories attached to the body, such as input keyboards or control panels.
• FIG. 1 shows a schematic perspective representation of an exemplary embodiment of a device according to the invention with two sensor elements
• FIG. 2 shows a schematic representation of a controller of the device according to FIG.
• FIG. 3 shows a schematic representation of release switching stages for the device according to FIG.
• FIG. 4 shows a schematic perspective illustration of an alternative exemplary embodiment of a device according to the invention with a sensor element
• FIG. 5 shows a schematic representation of a pattern of the force acting on the body 3 for a control command.
• Figure 1 shows a schematic perspective view of an embodiment of a device 10 according to the invention for determining a force F acting on a body 3 in at least three spatial directions Fx, Fy, Fz with at least one, in the present embodiment with two sensor elements 1, 2 for attachment a surface 3 . 1 of the body 3 and an evaluation/control unit 6 .
• the body 3 shown can be a partial segment, for example an arm or a section of an arm, of a manipulator, for example an industrial robot or a bid.
• the body 3 can have any conceivable shape and, of course, can also have components that can be moved relative to one another.
• the body 7 comprises a drive unit 7, by means of which the body 7 can be moved either relative to other components or relative to the ground.
• the body 3 designed as a sub-segment of an arm of a manipulator can be rotated and/or tilted relative to a further sub-segment of the arm of the manipulator.
• the drive unit 7 can be activated by means of the evaluation/control unit 6, which can be arranged either in or on the body 3 or can be designed as a separate unit.
• the sensor elements 1 , 2 each have a measuring surface 1 . 1 , 2 . 1, which—as shown by way of example for the sensor element 1—which individual sensor elements 1 . 3 includes .
• the individual sensor elements 1 . 3 are either for determining an individual force in one direction, usually perpendicular to the surface of the individual sensor element 1 . 3 , or determination of a single force in three spatial directions .
• the sensor elements 1, 2 each have at least one of the individual sensor elements 1.3, preferably a plurality of individual sensor elements 1.3.
• the sensor elements 1, 2 each have at least three of the individual sensor elements 1.3, preferably several individual sensor elements 1.3.
• the sensor elements 1, 2 have at least 15, for example 16, particularly preferably at least 20, in the present exemplary embodiment 24 individual sensor elements 1.3 arranged in a 4 ⁇ 4 grid.
• a larger number of individual sensor elements 1.3 can improve the resolution, regardless of whether the individual sensor element 1.3 determines the force in one or in three spatial directions.
• the individual sensor elements 1.3 are preferably arranged in a grid or a polar arrangement, for example as shown in the figures in rows and columns with the same grid dimensions. In particular, it is essential for the evaluation to know the relative orientation of the individual sensor elements 1.3 to one another.
• the force acting on the sensor element 1, 2 in three spatial directions Ex, Fy, Fz can be determined in such a way that a projection of the forces acting on the individual sensor elements 1.3 onto a virtual point 1.2, 2.2 of the sensor element 1, 2 is carried out, in particular by means of the evaluation/control unit 6.
• the virtual point 1.2, 2.2 is in particular on the measuring surface 1.1, 2.1, for example centrally.
• the force acting on the sensor element 1, 2 in particular at the virtual point 1.2, 2.2 can be measured in three spatial directions, i.e in particular the three force components Ex, Fy, Fz can be determined.
• Each of the two sensor elements 1, 2 described above enables the force acting on the sensor elements 1, 2 and thus also on the body 3 to be determined in three spatial directions.
• a method for determining a force acting on the body 3, in particular a manipulator in at least three spatial directions with exactly one sensor element 1, 2 mounted on the surface 3.1 of the body 3, which comprises at least three individual sensor elements 3.1, with each individual sensor element 1.3 for determining of an individual force in one direction, or which comprises at least one individual sensor element 1.3, which is designed to determine an individual force in three spatial directions, and an evaluation/control unit 6, the following steps can then be carried out: First, each is applied to each individual sensor element 1.3 single force determined. Then the force acting on the sensor element 1, 2 in three spatial directions Ex, Fy, Fz is calculated by projecting the individual forces onto a virtual point 1.2, 2.2 of the sensor element
• the force acting on the body 3 can be determined in a simple manner not only in three but in six spatial directions, ie the acting forces Ex, Fy, Fz and the acting torques Mx, My, Mz .
• the sensor elements 1 , 2 can be arranged at a distance A from one another, with the sensor element 1 being able to have the distance a from a virtual point 4 of the body 3 and the sensor element 2 being able to have a distance b from the virtual point 4 of the body 3 .
• the distance A preferably corresponds to the sum of the distances a and b.
• the forces acting on the sensor elements 1 , 2 are projected onto the virtual point 4 of the body 3 , in particular by means of the evaluation/control unit 6 . Since the virtual point 4 is not in the measuring surface 1.1, 2.1 of the sensor elements 1, 2, but at a distance from it, by considering the position of the individual sensor elements 1.3 relative to the virtual point 4 and evaluating the absolute values of the values on the individual sensor elements 1.3 acting individual forces, in addition to the forces Ex, Fy, Fz acting in three spatial directions, the torques Mx, My, Mz acting around the axes can also be determined.
• a method for determining a force acting on the body 3, in particular a manipulator in at least three, preferably in six, spatial directions with at least two sensor elements 1, 2 spaced apart from one another on the surface 3.1 of the body 3, each of which has at least three individual sensor elements 3.1 each individual sensor element 1.3 being designed to determine an individual force in one direction, or each comprising at least one individual sensor element 1.3 which is designed to determine an individual force in three spatial directions, and an evaluation/control unit 6, the following steps can then be carried out: First, for each sensor element 1, 2 each individual force acting on each individual sensor element 1.3 is determined. Then the force acting on the sensor element 1, 2 is calculated in three spatial directions by projecting the individual forces onto a virtual point 1.2, 2.2 of the sensor element 1, 2.
• the forces Ex, Fy, Fz and torques Mx, My, Mz acting on the body 3 are calculated by projecting the forces acting on the sensor elements 1, 2 onto a virtual point 4 of the body 3, which in particular is spaced apart from the sensor elements 1, 2 is calculated.
• the sensor element 1 shown there differs from the sensor element 1 shown in FIG. 1 in that it has a cover 1.4 that is freely mounted relative to the sensor element 1 and is arranged in particular parallel to the measuring surface 1.2.
• the cover 1.4 can be fixed, for example, on the surface 1.3 of the body, but can be moved relative to the sensor element 1 and in particular to the measuring surface 1.2. A user thus grips the outer surface of the cover 1.4, but the cover 1.4 is connected to the individual sensor elements 1.3, so that the force exerted on the cover 1.4 is transmitted to the individual sensor elements 1.3 via the back of the cover 1.4.
• the virtual point 1.2 is at a distance from the outer surface of the cover 1.4 in the measuring surface 1.2, which enables not only the three force components Ex, Fy, Fz to be determined in three spatial directions, but also the effective torques Mx, My, Mz.
• FIG. 1 shows the sensor elements 1, 2 as planar sensor elements 1, 2, which are shown tangentially to the curved surface 3.1 of the body 3 in a non-realistic way to simplify the illustration.
• the sensor elements 1, 2 preferably adapt to the surface 3.1 of the body 3.
• the sensor elements 1, 2 can be made of a flexible material.
• the sensor elements 1, 2 can be applied to the body 3 in the manner of an artificial, tactile skin.
• a large number of sensor elements 1, 2 can be arranged on the surface 3.1 of the body 3 and in particular can cover a large part of the surface 3.1, preferably the entire surface 3.1, of the body 3.
• a manipulated variable is preferably determined based on the force acting on the body, which the drive unit 7 converts into a corresponding movement of the body 3 in the direction of the acting force.
• a controller 5 is preferably provided for this purpose, in particular in the evaluation/control unit 6, which is shown schematically in FIG.
• the controller 5 is intended to carry out a subsequent movement of the body 3 in the direction of the force imbalance on the basis of the change in the force balance of the body 3 .
• the controller 5 can comprise a controlled system 5.3 and a control device 5.4, with the control device 5.4 receiving a control difference 5.8 as an input value, which results from an actual value 5.1 and a setpoint value 5.6 in a comparison element 5.7.
• Actual value 5.1 corresponds in particular to the force acting on body 3, which was determined using sensor elements 1, 2.
• the target value 5.6 can be defined, for example, by the balance of forces.
• the controlled system 5.3 delivers a controlled variable 5.2, which can specify the manipulated variable for the drive unit 7.
• Disturbance variables 5.5 can be taken into account in the controlled system 5.3.
• the movement of the body that is then carried out can be, for example, a linear movement or a rotary movement.
• the center of the movement can be placed at any point of the body 3 by a kinematic transformation, for example at the virtual point 4, but also at other points.
• the evaluation/control unit 6 and the drive unit 7 make it possible to determine one or more spatial directions, so that specific movements can be carried out in desired spatial directions.
• the forces acting on the body are then introduced into the controller 5 as actual values 5.1, the actual values 5.1 are compared with the target value 5.6 and a manipulated variable for a movement control to achieve the target value 5.6 is determined in order to determine a method for controlling the movement of the body 3 to provide.
• disturbance variables 5.5 in particular in the controlled system 5.3, can also be taken into account in the controller 5.
• Data and signal transmission between all components can be wired or wireless.
• all of the individual sensor elements 1.3 can be used for the evaluation. There is also the possibility of dividing the individual sensor elements 1.3 into two groups of individual sensor elements 1.3', 1.3'', the group of the individual sensor elements 1.3', which is illustrated in FIG. 1 without hatching, being independent of the group of the individual sensor elements 1.3''. , which is shown in Figure 1 for illustration with hatching, can be evaluated, for example, to enable a redundant evaluation.
• the individual sensor elements 1.3′, 1.3′′ in each group are preferably each arranged in a grid or polar arrangement, the grids or polar arrangements being arranged in particular in an interlocking manner, for example in the manner of a chessboard (cf. FIG. 1 or FIG. 4).
• each sensor element 1, 2 If there are several sensor elements 1, 2, a separate and/or independent evaluation of each sensor element 1, 2 is also possible in order to be able to carry out an additional plausibility check and, for example, to check whether a force is applied to each of the sensor elements 1, 2 and/or by a to allow further redundancy.
• the force acting on the body can thus be determined independently of one another by means of two groups of individual sensor elements 1 . 3'. 1 . 3 '' done .
• Typical safety-relevant release switches for movements of the body 3 can have three switching stages, namely a switching stage S1, in which the switch is not actuated, a switching stage S2, in which a movement of the body 3 is released, and a switching stage S3, in which an emergency stop takes place.
• a minimum force value Gl and a maximum force value G2 can be defined as the lower and upper switching threshold, with the switching stage S l at a force below the minimum force value Gl, the switching stage S2 at a force between the minimum force value Gl and the maximum force value G2 and the switching stage S3 is present at a force above the maximum force value G2 (cf. FIG. 3, in which an example of the amount F of the forces acting on the sensor elements 1, 2 is plotted as a function of the time t).
• the movement of the body 3 can be released when the amount F of the force acting on the sensor element 1, 2 is in the range of the switching stage S2 for one of the sensor elements 1, 2.
• the safety function is improved if, as shown in FIG.
• the movement of body 3 is released when for both sensor elements 1, 2 the amount F of the force acting on sensor element 1, 2 is in the range of switching stage S2.
• the force acting on the body 3 can then first be determined using the sensor elements 1, 2, then the determined force, in particular the amount F of the averaged force, with a predetermined minimum force value Gl and/or a maximum Force value G2 are compared and the movement of the body 3 is released if the determined force or the amount F of the determined force is greater than the minimum force value Gl and/or less than the maximum force value G2.
• patterns of the force acting on the body 3 for control commands can be stored in the evaluation/control unit 6, the patterns representing force profiles as a function of the time t.
• the force acting on body 3 as a function of time t in particular the amount F of the force acting on body 3 as a function of time t , can be compared with the stored patterns in order to identify such patterns and then the corresponding ones implement control command.
• FIG. 5 shows an example of a force profile in which the sensor element 1 is tapped twice. The force maxima occur at times t1 and t2.
• the pattern can be recognized and the corresponding control command linked to the pattern and stored accordingly in the evaluation/control unit, for example the current position of the body 3, for example an arm of a manipulator, can be stored or operation of accessories attached to the body 3, such as an input field, can be enabled.
• the evaluation/control unit for example the current position of the body 3, for example an arm of a manipulator
• the body 3 can be stored or operation of accessories attached to the body 3, such as an input field, can be enabled.

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• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Robotics (AREA)
• Mechanical Engineering (AREA)
• Human Computer Interaction (AREA)
• Chemical & Material Sciences (AREA)
• Analytical Chemistry (AREA)
• Manipulator (AREA)
• Control Of Position Or Direction (AREA)
• Force Measurement Appropriate To Specific Purposes (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2020
  • 2020-09-30 DE DE102020125583.7A patent/DE102020125583A1/de active Pending
• 2021
  • 2021-09-15 JP JP2023519699A patent/JP2023543845A/ja active Pending
  • 2021-09-15 EP EP21777728.3A patent/EP4222465A1/de active Pending
  • 2021-09-15 US US18/029,434 patent/US20230366761A1/en active Pending
  • 2021-09-15 WO PCT/EP2021/075307 patent/WO2022069224A1/de unknown
  • 2021-09-29 TW TW110136187A patent/TWI819382B/zh active

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