EP3946829A1

EP3946829A1 - Robot gripper, and method for operating a robot gripper

Info

Publication number: EP3946829A1
Application number: EP20717767.6A
Authority: EP
Inventors: Andreas SPENNINGER; Tim Rokahr
Original assignee: Franka Emika GmbH
Current assignee: Franka Emika GmbH
Priority date: 2019-03-27
Filing date: 2020-03-19
Publication date: 2022-02-09
Also published as: WO2020193340A1; CN113631331A; DE102019107851A1; JP2022526351A; DE102019107851B4; US20220184812A1; JP2024023695A; KR20220020249A

Abstract

The invention relates to a robot gripper (100) and to a method for operating such a robot gripper (100). The robot gripper (100) comprises: at least one drive unit AE (101) for driving a powertrain AS (102) with a number N of active elements WE_n (103), wherein each active element WE_n (103) has a working region AB_n which is arranged in a body-fixed manner relative to the robot gripper, in which each active element WE_n can be moved, and which can be reached by each active element; a control unit (104) for controlling the at least one drive unit AE (101); and a sensor system (105) that is connected to the control unit (104) for ascertaining forces/moments F_ext,WEn(t), where n = 1, 2, _…, N and N ≥ 1, which are applied externally to the individual active elements WE_n (103). The control unit (104) is designed such that a collision monitoring process can be carried out for the active elements WE_n (103), and in the event of a detected collision event for an active element WE_n (103), the drive unit AE (101) is actuated according to a specified operation, having the following steps: providing (201) a defined region B_n within the working region AB_n for each active element WE_n; carrying out (202) the collision monitoring process for the active elements WE_n (103) only if the respective active element WE_n (103) is located outside of the assigned region B; and deactivating the collision monitoring process for the active elements WE_n when the respective active element WE_n is located at least partly within the assigned region B_n.

Description

Robot gripper and method for operating a robot gripper

The invention relates to a robot gripper and a method for operating a

Robotic gripper.

Robot grippers (also called: “gripper” or “gripping system” or “effector” or “end effector”) are known in the prior art. Robot grippers are typically arranged at the distal end of robot manipulators and perform tasks such as gripping and / or holding objects / tools.

A robot gripper typically includes a drive unit, a drive train (also called a kinematic system) that moves the active elements, a mechanical interface for releasably and firmly connecting the robot gripper, for example to a robot manipulator, an energy interface for supplying the energy required for operating the robot gripper , as well as a control signal interface for

Supply of control signals (e.g. from a central robot control unit). Active elements are those elements of the robot gripper which, when gripping and holding an object, have direct contact with the object and can exert a gripping force on the object. There are several ways a robotic gripper can hold an object. A distinction is made here between, for example, different pairs of effects: pairing of forces, pairing of shapes, pairing of substances. There are also a variety of

Configurations of the active elements themselves, for example as gripper jaws (in the case of a parallel jaw gripper) or as multi-link fingers (in the case of an artificial hand)

The drive unit generates what is required for the gripping or holding process

Kinetic energy. The drive unit drives the output train and thus generates corresponding movements of the active elements. This makes it possible for the robot gripper to open, close and hold an object.

The output train is used to transmit the generated by the drive unit

Kinetic energy to the active elements. It thus converts a movement of the drive unit into an output movement of the robot gripper, ie into a corresponding movement of the active elements.

The object of the invention is to provide a robot gripper which enables operation with improved safety.

The invention results from the features of the independent claims. The dependent claims relate to advantageous developments and refinements. Further features, possible applications and advantages of the invention emerge from the following description and the explanation of exemplary embodiments of the invention which are shown in the figures.

A first aspect of the invention relates to a method for operating a robot gripper, the robot gripper comprising: at least one drive unit AE for driving a drive train AS with a number N of active elements WE _n , the active elements WE _n each having a working area AB fixed to the body relative to the robot gripper _n have in which the respective active elements WE _{n are} movable and which they can reach; a control unit for controlling the at least one drive unit AE, and a sensor system connected to the control unit for determining forces / _torques F _{ext, WEn} (t) applied externally to the individual active elements WE _n , with n = 1, 2, ..., N and N>1; the control unit being designed and set up in such a way that collision monitoring can be carried out for the active elements WE _n , and that in the event of a collision event detected for an active element WE _n , the drive unit AE is controlled according to a predetermined operation, with the following steps: for the active elements WE _n Providing a respective area B _n within the respective working area AB _n , and performing the collision monitoring for the active elements WE _n only when the respective active elements WE _{n are} outside the area B _n and

Deactivating the collision monitoring for the active elements WE _n when the respective active elements WE _{n are} at least partially within the assigned area B _n .

In the present case, the drive unit AE converts energy provided to the robot gripper (for example pneumatic energy, hydraulic energy or electrical energy) into mechanical energy, ie into a movement. This movement is advantageously a translational and / or a rotational movement. The drive unit is advantageously an electric motor that converts the provided electrical energy (voltage U, current I) into a mechanical rotation converts. Depending on the application, other drive units, such as a hydraulic motor or a pneumatic motor, are of course also suitable for driving the output train. The drive unit advantageously drives several active elements WE _n , in particular two active elements WE _{n = 1 2} . The robot gripper advantageously has a plurality of drive units which each drive one or more active elements WE _n . The drive unit AE can in particular comprise a transmission for stepping down or stepping up a rotational movement.

The output train AS (also called: kinematic system) transmits the mechanical movement generated by the drive unit AE to one or more active elements WE _n , so that they move accordingly. A large number of implementations are known in the prior art for the mechanical implementation of the output train AS in a robot gripper. The output train AS particularly advantageously comprises a belt, in particular a toothed belt.

The working areas AB _{n of} the active elements WE _n each indicate an area which is arranged fixed to the body relative to the robot gripper and in which the active elements WE _n can be moved and which they can reach. The working areas AB _n are thus defined in particular by the area that is spanned between the active elements WE _n when the active elements WE _{n are} opened to the maximum. Since the work areas AB _n are defined in a fixed manner relative to the robot gripper, the work areas AB _n always remain the same regardless of the position and location of the robot gripper.

According to the invention, the robot gripper has a sensor system for determining external forces / moments F _ex t _, wEn (t) applied to the individual active elements WE _n , with n = 1, 2,..., N and N> 1. Forces / moments that are exerted on other parts of the robot gripper, for example on a housing of the robot gripper, are therefore not detected by this sensor system.

In a particularly advantageous further development of the proposed method, a position q _{AE of} the drive unit AE is / are determined with a position sensor and / or a position q _AS of the drive train is determined with a position sensor and / or a drive unit speed q _{AE of} the drive unit AE is determined with a speed sensor / or with a speed sensor one The output train speed q _{AS of} the output train AS is determined and / or a torque t _{AE of} the drive unit AE is determined with a torque sensor and / or a torque T _AS in the output train AS is determined with a torque sensor and / or a motor current I _{M of} an electric motor of the drive unit AE is determined with a current sensor determined.

No sensors are advantageously arranged on the active elements WE _n . This eliminates the need for a corresponding cable connection to sensors on the active elements WE _n . The active elements WE _n are advantageously also exchangeable. So can be beneficial

Different types of active elements WE _{n are} connected to the output train AS, for example, to enable different active pairs, such as force pairing, shape pairing, material pairing when gripping or holding.

The provision of the areas B _n within the work areas AB _n can be done, for example, by appropriate inputs on the control unit, by reading out a corresponding data memory of the control unit, by data transmission to the control unit via a data interface of the robot gripper, by a manual or automated "teach-in “Process on the robot gripper can be carried out after the following storage in a data memory of the control unit.

According to the invention, the control unit is designed and set up in such a way that collision monitoring for the active elements WE _{n is} only carried out if the respective active elements WE _{n are} outside the assigned areas B _n and the collision monitoring for the active elements WE _{n is} deactivated when the respective active elements WE _n are located Active elements WE _{n are} at least partially located within the respectively assigned areas B _n .

The areas B _n are advantageously defined as a function of an external geometry AG of an object to be gripped. The outer geometry AG can be defined by the diameter of the object, for example in the case of a spherical object. The areas B _{n are} advantageously selected / defined in such a way that the areas B _n include the outer geometry AG (the edge / the surface of the object) of the object to be gripped and a difference area DB _P adjoining it to the outside: B _n = AG + DB _P. The size of the difference area DB _P depending on the task, applicable safety standards (e.g. trapping protection) and / or the

Sensitivity / breaking strength of the object to be gripped selected.

During the execution of the method in which an object is to be grasped, the collision monitoring / collision detection is consequently only carried out outside the areas B _n , ie outside a zone (difference area DB _P ) around an object which is optimally positioned for grasping. In this example, collision monitoring / collision detection is deactivated within this zone.

The working areas AB _{n are} each advantageously a three-dimensional or a two-dimensional or a one-dimensional area. The areas B _{n are} each advantageously a three-dimensional or a two-dimensional or a one-dimensional area.

In a particularly preferred development of the proposed method, the robot gripper is designed as a parallel jaw gripper with two active elements WE _{n = 1 2} , a common working area AB and a common area B being defined by spacing areas of the active elements WE _{n = 1 2} . The working area AB is advantageously defined as the distance area from a minimum distance A _M IN to a maximum distance A _MAc that the active elements WE _{n = 1 2} can _assume from one another. The area B of this development is correspondingly specified by a maximum distance limit value A _B , depending on the task, and thus contains all distances A from A _M IN to distance A _B.

The area B is thus defined by the distances A between the active elements WE _{n = i, 2} from one another, for which the following applies: A _{M | N} s A <A _B or A _{M | N} i A <A _B and A _B <A _MAc In this

In a further development, collision monitoring for the active elements WE _{n = i, 2 is} only carried out if the active elements WE _{n = 1 2 have} a distance A for which the following applies: A> A _B or A> A _B. The active elements (gripper jaws) of the parallel jaw gripper particularly preferably have no sensors.

The process-based activation or deactivation of the collision monitoring depending on a current position of the active elements WE _n and depending on the defined areas B _n is basically independent of whether an object is arranged relative to the robot gripper in such a way that it is also gripped by the robot gripper can be. That is, even if no object is arranged between the active elements WE _n , collision monitoring for the active elements WE _{n is} only carried out if the respective active elements WE _{n are} outside the assigned area B _n and the collision monitoring for the active elements WE _n is deactivated when the respective active elements WE _{n are} at least partially within the assigned area B _n .

An advantageous development of the robot gripper is characterized in that the robot gripper has a sensor with which the presence or absence of an object in a gripping area of the robot gripper can be detected, ie that the sensor detects that an object is arranged in such a way that it is Robot gripper can currently also be gripped. If this sensor detects an object in the gripping area, the collision monitoring for those active elements WE _{n is} then deactivated, provided that they are at least partially within the predefined areas B _n . If this sensor does not detect an object in the gripping area, the collision monitoring is advantageously not deactivated within the areas B _n . In this case, the collision monitoring is carried out in the entire work area of the

Robot gripper executed.

The sensor for determining an object in the gripping area of the robot gripper is advantageously, for example, a camera sensor, an ultrasonic sensor, a laser sensor

Infrared sensor, a capacitive sensor, an inductive sensor, a microwave sensor, or a combination thereof.

An advantageous further development of the proposed method is characterized in that the collision monitoring takes place on the basis of a predefined dynamic model of the robot gripper. The dynamic model is a mathematical model that allows the components of the robot gripper and their dynamic interactions to be simulated. The dynamic model is based in particular on the control unit for controlling and regulating the drive unit.

The collision monitoring for the active elements WE _{n is} advantageously carried out using a disturbance variable observer, in particular by a power observer or a pulse observer or a speed observer or a

Acceleration observer. An or are advantageous for collision monitoring several of the measured quantities: q _AE , q _AS , q _AE , q _AE q _AS , T _as , I _M used.

The variables: q _AE , q _AE or q _AS , q _{AS can} also be determined on the basis of corresponding time derivatives from the variables: q _AE or q _AS .

The collision monitoring is advantageously carried out on the basis of a comparison of a setpoint and an actual position for q _AE , q _AS .

According to a further development of the proposed method, the operation is selected from the following options from a non-exhaustive list:

Stopping the drive unit AE,

Control of the drive unit AE for gravitation compensation,

Control of the drive unit AE for friction compensation,

Controlling the drive unit AE in such a way that the active elements WE _n are continuously moved away from one another in a controlled manner,

Control of the drive unit AE in such a way that the active elements WE _n move away from one another in a reflex-like manner.

The areas B _{n are} advantageously defined within the

Working areas AB _n through a manual or automated teach-in process on the robot gripper. The teach-in process advantageously includes the following steps:

Gripping an object in such a way that each of the active elements WE _n makes mechanical contact with the object, wherein the active element WE _n

enclosed area defines the areas AG _n ,

Determination of the areas B _n by extending the areas AG _n to the outside by predetermined delta areas DB _P , so that the following applies: B _n = AG _n + DB _P , and

Save B _n .

B _n is preferably stored on a storage unit of the robot gripper.

A suitable selection of the areas B _n enables, in particular, clamping quantity travel when the gripper is operated in collaboration with a person prevented or at least significantly reduced during the automated gripping process of the robot gripper.

If, for example, a ball with a diameter of 5 cm (AG = 5 cm) is to be gripped with a parallel jaw gripper, and a common area B = AG + DB is advantageously defined for the two gripper jaws by a distance between the gripper jaws of 5.5 cm. As a result, if the ball is arranged in the center, it remains between the

Gripper jaws on each side of the ball 2.5 mm (= DB / 2) before a

Collision monitoring is deactivated when the gripper jaws move further towards one another. The 2.5 mm on each side of the ball are advantageously dimensioned in such a way that no human finger can fit between the gripper jaw and the ball.

The proposed method thus improves, in particular, the safety in the case of a collaboration between the robot gripper and an operator.

The robot gripper can, if it is connected to a manipulator of a robot, receive control commands from a central control unit of the robot. This

Control commands are transmitted to the control unit of the robot gripper. The

The control unit of the robot gripper implements these control commands and controls

basically the drive unit accordingly, with the inventive

Collision monitoring and the activation or deactivation of the collision monitoring according to the invention is carried out locally on the control unit of the robot gripper. The control unit of the robot gripper advantageously transmits recognized collisions for the active elements WE _n to a central control unit of the robot.

Another aspect of the invention relates to a robot gripper comprising: at least one drive unit AE for driving a drive train AS with a number N of active elements WE _n , the active elements WE _n each being fixed to the body relative to the

Robotic grippers have arranged work areas AB _n in which the active elements WE _{n are} each movable and which they can reach; a control unit for

Control and regulation of the at least one drive unit AE; and a sensor system connected to the control unit for determining forces / moments F _{ext, WEn} (t) externally applied to the individual active elements WE _n , with n = 1, 2, ..., N and N>1; wherein the control unit is designed and set up such that for the

Active elements WE _n collision monitoring can be carried out; the collision monitoring for the active elements WE _{n is} only carried out if the respective

Active elements WE _{n are located} outside of a predetermined assigned area B _n lying within the working area AB _n ; the collision monitoring for the active elements WE _{n is} deactivated when the respective active elements WE _{n are} at least partially within the assigned area B _n ; and if a collision event is detected for an active element WE _n , the drive unit is activated according to a predetermined operation.

The drive unit AE is advantageously an electric motor or a hydraulic actuator or a pneumatic actuator. The drive unit AE can also include a gear unit.

In a particularly preferred development, the robot gripper is as a

Parallel jaw gripper with two active elements WE _{n = i, 2} executed, with one

common work area AB and a common area B.

Distance ranges of the active elements WE _{n = i, 2 are} defined. The working area AB is advantageously defined as the distance range from a minimum distance A _{M | N} to a maximum distance A _M AX that the active elements WE _{n = i, 2} can assume from one another. The area B of this development is correspondingly specified by a maximum distance limit value A _B , depending on the task at hand, and thus contains all distances A from A _{M | N} to distance A _B.

The area B is thus defined by the distances A between the active elements WE _{n = 1 2} from one another, for which the following applies: A _M IN i A <A _B or A _M IN i A <A _B and A _B <A _M AX- In this

In a further development, collision monitoring for the active elements WE _{n = 1 2 is} only carried out if the active elements WE _{n = i, 2 have} a distance A for which the following applies: A> A _B or A> A _B. The active elements (gripper jaws) of the parallel jaw gripper particularly preferably have no sensors.

In an advantageous development of the robot gripper, the sensor system has a or several of the following sensors: a position sensor for determining a position q _{AE of} the drive unit AE and / or a position sensor for determining a

Position q _{AS of} the output train AS and / or a speed sensor for determining a drive unit speed q _{AE of the} drive unit AE and / or a speed sensor for determining a output train speed q _{AS of} the output train AS and / or a torque sensor for determining a

Torque t _{AE of} the drive unit AE and / or a torque sensor for

Determination of a torque T _AS in the output train AS and / or a current sensor for determining the motor current I _{M of} an electric motor of the drive unit AE.

In an advantageous development of the proposed robot gripper is

Control unit designed and set up in such a way that the collision monitoring takes place on the basis of a predetermined dynamic model of the robot gripper.

The control unit is advantageously designed and set up such that the

Collision monitoring is carried out using a disturbance variable observer,

in particular by a performance observer or an impulse observer or a speed observer or an acceleration observer.

One or more of the measured variables are advantageously used for collision monitoring: q _AE , q _AS , q _AE , q _AE, q _AS , q _AS, t _AE , t _AS , l _M. The

Quantities: q _AE , q _AE or q _AS , q _{AS can} also be determined on the basis of corresponding time derivatives from the quantities: q _AE or q _AS .

An advantageous further development of the robot gripper is characterized in that the drive unit AE is a motor which is coupled to the output strand AS via a transmission, and that a torque sensor for determining a torque T _AS im

Output train AS is connected between gearbox and output train. The motor is advantageously an electric motor.

The control unit is advantageously designed and set up in such a way that the operation is selected from the following options from a non-exhaustive list: Stopping the drive unit AE,

Control of the drive unit AE for gravitation compensation,

Control of the drive unit AE for friction compensation,

The robot gripper advantageously has a housing into which at least the

Drive unit AE and the control unit are integrated. The control unit advantageously comprises a processor, a memory unit and an interface for specifying setpoint control variables, for example from a central computer for controlling a

Robot to which the robot gripper is connected.

The invention finally relates to a robot or humanoid with a

Robotic gripper as described above.

Further advantages, features and details emerge from the following description in which at least one exemplary embodiment is described in detail - possibly with reference to the drawings. Same, similar and / or

functionally equivalent parts are provided with the same reference symbols.

Show it:

1 shows a highly schematic process sequence, and

2 shows a highly schematic structure of a proposed

Robotic gripper

1 shows a highly schematic sequence of a method for operating a robot gripper, the robot gripper comprising: at least one drive unit AE for driving a drive train AS with a number N of active elements WE _n , the active elements WE _n each being arranged one body-fixed relative to the robot gripper Have work area in which the active elements WE _{n are} movable and they can achieve a control unit for controlling the drive unit AE, and a sensor system connected to the control unit for determining forces / _torques F _{ext, WEn} (t) externally applied to the individual active elements WE _n , with n = 1, 2, ... , N and N> 1.

The control unit is configured and adapted for operative elements WE _n a collision monitoring autonomously and locally executable (that is, without requiring an external control unit or an external processor), and that when a working element WE _n detected collision event the drive unit according to a predetermined Operation is controlled autonomously and locally.

The method comprises the following steps, which are carried out when the robot gripper is in operation, in particular when the robot gripper grips an object.

In a first step 201 is carried out for the operating elements WE _n each providing a defined area B _n within the associated working area AB _n.

When the robot gripper is activated to carry out a gripping task, for example controlled by an external central control unit of a robot to which the robot gripper is connected, the control unit takes place in step 202

The robot gripper enables collision monitoring to be carried out autonomously for the

Active elements WE _n always when the respective active elements WE _{n are} outside the area B and a deactivation of the collision monitoring for the

Active elements WE _n when the respective active elements WE _{n are} at least partially within area B.

The control unit of the robot gripper advantageously generates a collision signal if a collision is detected for one of the active elements WE _n . The

Control unit of the robot gripper a deactivation signal if the

Collision monitoring for an active element WE _{n is} deactivated. The robot gripper advantageously provides the collision signal and / or the deactivation signal to a

Interface ready so that they can be forwarded to external control units.

In one embodiment of the proposed method, the collision monitoring deactivated for all active elements WE _n if at least one active element WE _{n is} at least partially within the assigned area B _n .

2 shows a highly schematic structure of a proposed robot gripper 100, which is designed as a parallel jaw gripper. The robot gripper 100 comprises: a drive unit 101, which in the present case is designed as an electric motor with a downstream gear 110, and which is used to drive a drive train 102 with a number N = 2 of active elements WE _{n = 1 2} 103 (also called: gripping jaws) . The drive unit 101 drives the active elements WE _{n = i, 2} 103 via the drive train 102 in such a way that they either move towards or away from one another and thus the distance A of the active elements WE _{n = i, 2} 103 changes accordingly.

The two active elements WE _{n = 1, 2} 103 have a common working area AB which is arranged fixed to the body relative to the robot gripper and in which the active elements WE _{n = 1 2} 103 can be moved or which they can occupy. The work area AB is composed in the present case of a first work area AB _{n = 1 of} the upper gripping jaw 103a shown in FIG. 2, which is from the position shown extends to a middle (dash-dot-dot line) and a second working area AB _{n = 2} in FIG

shown lower gripping jaw 103b, which from the position shown up to the middle (dash-dot-dot line) extends together.

The combined working area AB of the parallel jaw gripper thus corresponds in the present case to all distances A of the active elements WE _{n = i, 2} 103 from A = 0 (minimum distance between the active elements WE _{n = 1 2} ) up to or including the maximum distance which the active elements WE _{n = i, 2} 103 can assume from each other (marked in FIG. 2 as AB).

The parallel jaw gripper also has a control unit 104 for controlling the drive unit 101 and a sensor system 105 connected to the control unit 104 for ascertaining externally applied elements WE _{n = 1 2}

Forces / moments F _{ext, WEn} (t), with n = 1, 2, ..., N and N> 1.

In the present case, the sensor system 105 comprises a position sensor for determining a motor position q _{AE of} the electric motor, a current sensor for determining a Motor current I _{AE of} the electric motor and a torque sensor connected between the transmission 110 and the output train 102 for determining the torque T _AS . The measured variables q _AE , I _AE and T _AS are made available to the control unit 104.

The parallel jaw gripper 100 furthermore has an interface 11 for electrical energy and a control signal from an external control unit. The interface 1 1 1 is connected to the control unit 104 by at least one signal line 1 12 and at least one electrical line 1 13.

If the parallel jaw gripper 100 is connected, for example, as an effector to a manipulator of a robot, then the interface 1 1 1, for example

Control signals from a central control unit of the robot and electrical energy for the parallel jaw gripper 100 are provided.

The control unit 104 is designed and set up in such a way that collision monitoring can be carried out for the active elements WE _{n = 1 2} 103; the collision monitoring for the active elements WE _{n = i,} 2 103 is only carried out if the respective

Active elements WE _{n = 1 2} 103 are located outside a predetermined area B lying within the working area AB; the collision monitoring for the active elements WE _{n = 1 2} 103 is deactivated if the respective active elements WE _{n = 1 2} 103 are at least partially within the area B, and if a collision event is detected for an active element WE _{n = 1 2} , the drive unit 101 is driven according to a predetermined operation.

This collision monitoring is always carried out independently of control commands, for example an external robot malfunction.

The area B, i.e. the area in which the collision monitoring

is deactivated according to the invention, depending on the task at hand, is given by a distance limit value A _B , the area B being defined by a distance A between the active elements WE _{n = i} , 2, for which the following applies: A <A _B or A <A _B and A _B <A _MAc . In this development, collision monitoring for the active elements WE _{n = i} , 2 is only carried out if the active elements WE _{n = i} , 2 are at a distance of>or> A _B. The active elements particularly preferably have (Gripper jaws) of the parallel jaw gripper does not pick up any sensors.

In Fig. 2, the ranges given above are for a situation

illustrated in which a ball (in cross section) is arranged centrally between the gripper jaws 103a, 103b, the gripper jaws 103a, 103b each in the position of their maximum deflection, i.e. their maximum distance. The maximum distance between the gripper jaws shown defines the working area AB. Area B lying within working area AB specifies the area in which collision monitoring is deactivated. The area B is present by the

Diameter D = AG of the ball and defined by a safety zone DB / 2 on both sides of the ball.

If external forces / moments are exerted on the gripper jaws when gripping the ball, in which the gripper jaws are moved towards one another from the position shown, a corresponding collision is detected, provided that the gripper jaws are located outside of area B. The dedicated collision leads to a predetermined operation, in particular to a stop of the drive unit. Furthermore, a

Collision signal provided at the interface 1 1 1 for forwarding to an external control unit.

The collision monitoring in the control unit 104 takes place on the basis of a predetermined dynamic model of the parallel jaw gripper 100

Collision monitoring in the control unit 104 using a

Disturbance observer.

List of reference symbols

100 robot grippers

101 drive unit

102 output train

103 active elements WE _n

104 control unit

105 sensor system

1 10 gear

1 1 1 Interface for electrical energy and control signal from an external

Control unit

1 12 control signal line

1 13 electrical power line

201, 202 process steps

Claims

1. A method for operating a robot gripper, wherein the robot gripper (100)

includes:

at least one drive unit AE (101) for driving an output train AS (102) with a number N of active elements WE _n (103), each active element WE _n (103) having a work area AB _{n which is} fixed to the body relative to the robot gripper and in which the respective Active element

WE _{n is} movable and which it can reach

a control unit (104) for controlling the at least one drive unit AE (101), and

a sensor system (105) connected to the control unit (104) for determining external forces / moments F _{ext, WEn} (t) applied to the individual active elements WE _n (103), with n = 1, 2, ..., N and N> 1, the control unit (104) being designed and set up in such a way that collision monitoring can be carried out for the active elements WE _n (103), and that in the event of a collision event detected for an active element WE _n (103) the

Drive unit AE (101) is controlled according to a specified operation, with the following steps:

for each of the active elements WE _n providing (201) a defined area B _n within the respective working area AB _n , and

Carrying out (202) the collision monitoring for the active elements WE _n (103) only when the respective active elements WE _n (103) are outside the assigned area B _n and deactivates the

Collision monitoring for the active elements WE _n when the respective active elements WE _{n are} at least partially within the assigned area B _n .

2. The method according to claim 1,

in which the robot gripper (100) is a parallel jaw gripper with two active elements WE _{n = 1, 2} (103), where

a common working area AB of the two active elements WE _{n = 1 2} (103) and a common area B are defined by respective distance areas, specify the distances A of the active elements WE _{n = i, 2} (103) from one another, the working area AB all distances A of the active elements WE _{n = 1 2} (103) from a minimum distance A _M IN to a maximum distance A _M AX, the the active elements WE _{n = 1 2} can each occupy one another, comprises, the area B comprises all distances A of the active elements WE _{n = i, 2} (103) from A _M IN up to a predetermined distance A _B , where: A _{M | N} s A <A _B or A _{M | N} <A <A _B and A _B <AMAX, and

a collision monitoring for the active elements WE _{n = 1 2} (103) is only carried out if the active elements WE _{n = i, 2} (103) have a distance A>or> A _B.

Method according to one of Claims 1 or 2,

in which the collision monitoring takes place on the basis of a specified dynamic model of the robot gripper (100).

Method according to one of Claims 1 to 3,

in which the collision monitoring is carried out using a disturbance variable observer, in particular by a performance observer or a

Impulse observer or a speed observer or a

Acceleration observer.

Method according to one of Claims 1 to 4,

in which the sensor system (105) determines a position q _{AE of} the drive unit AE (101) with a position sensor and / or determines a position q _AS of the drive train AS (102) with a position sensor and / or with a

Speed sensor a drive unit speed q _AE the

Drive unit AE (101) determines and / or determines a drive train speed q _AS of drive train AS (102) with a speed sensor and / or determines a torque t _AE of drive unit AE (101) with a torque sensor and / or determines a torque T _AS with a torque sensor in the

Output train AS (102) determined and / or with a current sensor

Motor current I _{M of} the drive unit AE (101) is determined. Method according to claim 5,

one or more of the measured values for collision monitoring: be used .

Method according to one of Claims 1 to 6,

where the operation is selected from the following:

Stopping the drive unit AE (101),

Control of the drive unit AE (101) for gravity compensation, control of the drive unit AE (101) for friction compensation in the system drive unit AE (101) - output train AS (102),

Controlling the drive unit AE (101) in such a way that the active elements WE _n are continuously moved away from one another in a controlled manner, the drive unit AE (101) controlled in such a way that the active elements WE _n move away from one another in a reflex-like manner.

Method according to one of Claims 1 to 7,

in which the definition (201) of the areas B _n within the working areas AB _{n is carried out} by a manual or automated teach-in process on the robot gripper, and the teach-in process comprises the following steps:

Gripping an object in such a way that each of the active elements WE _n (103) makes mechanical contact with the object, the area enclosed by the active elements WE _n (103) defining the areas AG _n ,

Determine the areas B _n by turning the areas AG _n outwards

predefined delta areas DB _{P are} expanded so that: B _n = AG _n + DB _P , and

Save B _n .

Robotic gripper (100) comprising:

at least one drive unit AE (101) for driving an output train AS (102) with a number N of active elements WE _n (103), the active elements WE _n (103) each having working areas AB _n arranged fixedly relative to the robot gripper (100), in which the active elements WE _n (103) are each movable and which they can reach,

a control unit (104) for controlling and regulating the at least one drive unit AE (101), and a sensor system (105) connected to the control unit (104) for

Determination of forces / moments F _{ext, WEn} (t) applied externally to the individual active elements WE _n (103), with n = 1, 2, N and N> 1, the control unit (104) being designed and set up in such a way that a collision monitoring can be carried out for the active elements WE _n (103),

the collision monitoring for the active elements WE _n (103) is only carried out if the respective active elements WE _n (103) are located outside of a predetermined assigned area B _n lying within the working area AB _n ,

the collision monitoring for the active elements WE _n (103) is deactivated if the respective active elements WE _n (103) are at least partially within the assigned area B _n , and if a collision event is detected for an active element WE _n (103), the drive unit (101) is driven according to a predetermined operation.

10. Robot gripper (100) according to claim 9,

in which the sensor system (105) has: a position sensor for determining a position q _{AE of} the drive unit AE (101) and / or a position sensor for

Determination of a position q _{AS of} the output train AS (102) and / or a

Speed sensor for determining a drive unit speed q _{AE of} the drive unit AE (101) and / or a speed sensor for determining a drive train speed q _AS of the drive train AS (102) and / or a torque sensor for determining a torque t _AE of

Drive unit AE (101) and / or a torque sensor for determining a torque T _AS in the output train AS (102) and / or a current sensor for determining a motor current I _{M of} an electric motor of the drive unit AE (101).

1 1. Robot gripper (100) according to claim 9 or 10,

in which the drive unit AE (101) is a motor which is coupled to the output train (102) via a gear (1 10), and a torque sensor for determining a torque T _AS in the output train AS (102) between the gear (1 10) and Output train AS (102) is switched.

12. Robot or humanoid with a robot gripper (100) according to one of claims 9 to 1 1.