Robot arm with modular drive units and modular drive unit therefor

Abstract

A modular drive unit (A1, A2, A3, A4, A5, A6, A7) for adjusting a rotary joint of a robot arm (100) has: a servo motor with a motor housing (1, 1.1, 1.2, 1.3) and a drive shaft (2); a strain wave gear (4.1, 4.2) coupled to the drive shaft; a holding brake (3) coupled to the drive shaft; a drive encoder (5.1) for detecting a position of the drive shaft; an output encoder (5.2) for detecting a position of an output (4) of the strain wave gear; a servo controller (6) signal-connected to the drive encoder and the output encoder; a load sensor (7); and a hollow shaft (8) for passing the cable axially through the drive unit. The invention also relates to a robot arm having the drive unit.

Description

[0001] Description

[0002] Robot arm with modular drive units and modular drive unit for this purpose

[0003] The present invention relates to a robot arm with several rotary drives for adjusting one rotary joint of the robot arm and a modular drive unit for adjusting one rotary joint of the robot arm.

[0004] The object of the present invention is to improve a robot arm, preferably its manufacture, maintenance and / or operation, and / or to provide a drive unit for adjusting a rotary joint of a robot arm, with which a robot arm, preferably its manufacture, maintenance and / or operation, can be improved.

[0005] This problem is solved by a modular drive unit with the features of claim 1. Claim 7 provides protection for a robot arm with several rotary drives for adjusting each of the rotary joints of the robot arm, wherein one or more of these rotary drives (each) preferably comprises a drive unit as described herein. The dependent claims relate to advantageous embodiments.

[0006] According to one embodiment of the present invention, a modular drive unit for adjusting a rotary joint of a robot arm comprises:

[0007] - a servo motor with:

[0008] - a one-piece or multi-piece engine housing, which may in particular include one or more gearbox housing parts; and

[0009] - a one- or multi-part drive shaft, preferably a one- or multi-part hollow shaft, wherein the drive shaft is in one embodiment non-rotatably connected to a rotor of the servo motor, and in a further development non-rotatably connected;

[0010] - a wave gear coupled to the drive shaft, which is available in one version

[0011] - a wave generator, preferably non-rotatably connected to the drive shaft, preferably in a non-rotatable manner; - a circular spline, preferably non-rotatably connected to the motor housing; and

[0012] - a flexspline which in one embodiment forms an output of the wave gear or part of an output of the wave gear or is coupled to an output of the wave gear, preferably rotationally fixed, in one embodiment rotationally fixed; has;

[0013] - a holding brake coupled to the drive shaft, preferably non-rotatably connected;

[0014] - a drive encoder that detects, is set up for, or is used to detect the position of the drive shaft;

[0015] - an output encoder that detects the position of one or the output of the wave gear, or is set up or used for this purpose;

[0016] - a signal-connected servo controller, in one version wired to the drive encoder and the output encoder, which is preferably integrated into the modular drive unit;

[0017] - a load sensor, preferably a single- or multi-axis force and / or torque sensor and / or for detecting a load acting on the output, in particular a force acting on the output and / or a torque acting on the output; and

[0018] - a hollow shaft, preferably non-rotatably connected to the motor housing, through which one or more cables, preferably for power supply and / or control of the servo motor and / or the holding brake and / or for communication with a servo controller connected in series with the servo controller of a subsequent drive unit and / or a power supply of a subsequent drive unit, can be guided axially through the drive unit, in a particular embodiment, or which is equipped or used for this purpose.

[0019] This allows for a fully integrated and modular drive solution for the robot arm in a single design, in which the aforementioned components are fully integrated, enabling particularly advantageous operation of the robot arm. Additionally or alternatively, this can improve, and in particular simplify and / or accelerate, the assembly and / or (partial) disassembly and / or maintenance of the robot arm.

[0020] By using the wave gear, which is advantageously integrated into the drive unit, advantageous transmission ratios can be achieved particularly advantageously, especially precisely, and thereby the robot arm or the corresponding rotary joint can be adjusted particularly efficiently and / or precisely.

[0021] By using the holding brake, which is advantageously integrated into the drive unit, the corresponding swivel joint can be set particularly efficiently and / or precisely when required.

[0022] By using a combination of a (gearbox)-side drive encoder and a (gearbox)-side output encoder, advantageously integrated into the drive unit, the (re)calibration effort can be advantageously reduced and / or a difference between the input and output speeds of the wave gear can be determined, and based on this, for example, a load torque can be determined and / or a safety check can be carried out, for example, an error reaction can be triggered if a difference between the input and output speeds, taking into account a target gear ratio of the wave gear, exceeds a predetermined tolerance range.

[0023] In one embodiment, the drive encoder and / or the output encoder (each) is an absolute (measuring) encoder. This advantageously reduces the (re)calibration effort. In one embodiment, the drive encoder detects a rotation or rotational position of the drive shaft relative to the motor housing, and / or the output encoder detects a rotation or rotational position of the output of the wave gear relative to the motor housing. In one embodiment, the servo controller (wave gear) is arranged on the output side.

[0024] By integrating the servo controller directly into the drive unit, the assembly and / or (partial) disassembly and / or maintenance of the robot arm can be improved, in particular simplified and / or accelerated. In one embodiment, the servo controllers of several drives are connected to each other in series via signals, preferably daisy-chained, so that one or more servo controllers each transmit signals from a subsequent servo controller, preferably also signals transmitted by this subsequent servo controller to one or more further subsequent servo controllers, towards an interface of the robot arm, in particular to the interface or a preceding servo controller, and / or output signals from the interface to a subsequent servo controller, preferably also signals to be transmitted by this subsequent servo controller to one or more further subsequent servo controllers, or are configured or used for this purpose.This allows for a particularly advantageous operation of the robot arm in one embodiment and / or improves, in particular simplifies and / or accelerates, the assembly and / or (partial) disassembly and / or maintenance of the robot arm.

[0025] By using a load sensor, advantageously integrated into the drive unit, a particularly advantageous operation of the robot arm can be achieved in one embodiment, and / or the assembly and / or (partial) disassembly and / or maintenance of the robot arm can be improved, in particular simplified and / or accelerated. In particular, this can advantageously enable compliance control, especially impedance control, of the robot arm, in which loads acting on the robot arm are detected by means of the load sensor(s) and the robot arm is controlled to avoid or follow these loads. In one embodiment, the load sensor is signal-connected to the servo controller, preferably such that the servo controller can transmit data based on signals from the load sensor, optionally via further servo controllers, to a robot arm controller or interface.

[0026] The possibility of axial cable routing through the drive unit via the hollow shaft improves cable management within the robot arm and / or facilitates, in particular simplifies and / or accelerates, the assembly and / or (partial) disassembly and / or maintenance of the robot arm. In one embodiment, the drive shaft is rotatably mounted on, preferably within, the motor housing, preferably via one or more rolling bearings. Additionally or alternatively, in another embodiment, the drive shaft and the output shaft of the wave gear are rotatably mounted to one another, preferably via one or more rolling bearings. Additionally or alternatively, in one embodiment, the drive shaft engages the hollow shaft, preferably concentrically, or in another embodiment, the hollow shaft passes through the drive shaft. Additionally or alternatively, in another embodiment, the output shaft of the wave gear is rotatably mounted on the motor housing, preferably via one or more rolling bearings.

[0027] One or more of these features can improve, in particular simplify and / or accelerate, the assembly and / or (partial) disassembly and / or maintenance of the robot arm in a given design. Additionally or alternatively, one or more of these features can advantageously increase rigidity and / or reduce weight and / or installation space in a given design.

[0028] In one embodiment, the holding brake is an electrically operated (actuated) and / or self-closing brake, or one that closes without a power supply or actuation. Additionally or alternatively, in another embodiment, the holding brake is arranged in the motor housing, preferably at the edge.

[0029] One or more of these features can improve, in particular simplify and / or accelerate, the assembly and / or (partial) disassembly and / or maintenance of the robot arm in a given design. Additionally or alternatively, one or more of these features can enhance safety in a given design.

[0030] In one embodiment, the holding brake and the servo controller are arranged on opposite sides of the wave gear. Additionally or alternatively, in another embodiment, the servo controller and the drive encoder are arranged on the same side of the wave gear. Additionally or alternatively, in yet another embodiment, the servo controller and the output encoder are arranged on the same side of the wave gear.

[0031] One or more of these features can improve, in particular simplify and / or accelerate, the assembly and / or (partial) disassembly and / or maintenance of the robot arm in a given design. Additionally or alternatively, one or more of these features can improve, in particular simplify, cable routing in a given design.

[0032] In one embodiment, the stator of the servo motor is bonded to the motor housing; in a further development, it is glued to the motor housing. Additionally or alternatively, in one embodiment, the motor housing has a cover through which the stator of the servo motor and / or the holding brake is inserted, or which is provided for or used for this purpose. Additionally or alternatively, in one embodiment, the motor housing has at least one gearbox housing section in which the wave gear is at least partially arranged and / or on which the output of the wave gear is rotatably mounted. One or more of these features can improve, in particular simplify and / or accelerate, the assembly and / or (partial) disassembly and / or maintenance of the robot arm in one embodiment.Additionally or alternatively, this can improve the support of the output in one design and / or provide an advantageous, in particular more protected and / or more compact, accommodation for the wave gear.

[0033] In one embodiment, the drive unit has a temperature sensor that detects the temperature of the drive unit, preferably the servo motor and / or wave gear and / or servo controller, and preferably reports this temperature to the servo controller, or is configured or used for this purpose. In one embodiment, the temperature sensor is arranged on the stator of the servo motor; in a further development, it is integrated into the stator.

[0034] This allows, in particular, the operation of the robot arm to be improved, for example, by taking into account the temperature(s) detected during operation and / or shutdown of the robot arm. According to one embodiment of the present invention, a robot arm has several rotary drives, each of which adjusts a rotary joint of the robot arm or is configured or used for this purpose, wherein one or more of these rotary drives (each) comprise a modular drive unit as described herein, or in a further development (each) is a modular drive unit as described herein.

[0035] In one embodiment, the robot arm has a base, preferably stationary or mobile, and an end flange, preferably with an interface for attaching an end effector and / or an end effector. In a further embodiment, in one or more of the drive units, the motor housing, preferably fixed, is connected to an end-flange-side or distal structural member of the robot, and the output of the wave gear is connected to a base-side or proximal structural member of the robot, which in one embodiment are connected to each other by the joint adjustable by the drive unit.

[0036] This can improve, in particular simplify and / or accelerate, the assembly and / or (partial) disassembly and / or maintenance of the robot arm in one version. Additionally or alternatively, this can improve, in particular simplify, cable routing in another version.

[0037] In one embodiment, several of the drive units, preferably their servo controllers, are connected to each other in series via cables, preferably in a daisy-chain configuration. Additionally or alternatively, a servo controller, preferably a fixed-base model, of a proximal drive unit is connected to a robot arm controller via a signal interface, particularly via cables.

[0038] This allows, in one embodiment, the assembly and / or (partial) disassembly and / or maintenance of the robot arm to be improved, in particular simplified and / or accelerated. Additionally or alternatively, this allows, in another embodiment, the cable routing to be improved, in particular simplified. In one embodiment, the robot arm has at least six, and in a further development at least seven, rotary joints adjustable by the drive units. Additionally or alternatively, in one embodiment, it is configured as a cobot or collaborative robot that works in direct contact with humans, or is used as a cobot.

[0039] The present invention is particularly advantageous for such robot arms, especially due to the integrated sensors.

[0040] Further advantages and features will become apparent from the dependent claims and the exemplary embodiments. These are shown, in part schematically:

[0041] Fig. 1: a robot arm with several modular drive units according to one embodiment of the present invention; and

[0042] Fig. 2: one of the drive units in an axial section.

[0043] Fig. 1 shows a robot arm 100 with several rotary joints, which are indicated in Fig. 1 by dashed-dotted axes of rotation.

[0044] The robot arm 100 has a base 110 and an end flange 120 and is controlled by a robot arm controller 200, preferably via EtherCat, in particular FOE&FSOE.

[0045] For adjusting the rotary joints – indicated by a movement arrow in Fig. 1 – the robot arm has modular drive units A1-A7 according to one embodiment of the present invention, one of which is shown in an axial section in Fig. 2. Preferably, several, or in one embodiment all, of the drive units A1-A7 are each a drive unit, as explained below with reference to Fig. 2.

[0046] The drive unit shown in an axial section in Fig. 2 according to an embodiment of the present invention comprises a servo motor with a motor housing 1 and a drive shaft 2. An electrically operated and self-closing holding brake 3, coupled to the drive shaft 2, is arranged at the edge (right side in Fig. 2) of the motor housing 1 and connected to a receiving flange 1.3 of the multi-part motor housing.

[0047] A wave gear is also coupled to the drive shaft 2. For this purpose, the drive shaft 2 has a wave generator of the wave gear or is rotationally fixed to it. A flex spline 4.1 of the wave gear forms part of its output 4 or is rotationally fixed to it. A circular spline 4.2 of the wave gear is partially arranged in a gearbox housing part 1.1 of the motor housing.

[0048] A drive encoder 5.1 is coupled to the drive shaft 2, and an output encoder 5.2 is coupled to the output of the wave gear.

[0049] The drive encoder 5.1 and the output encoder 5.2 are connected to a servo controller 6, which is also connected to a load sensor 7, in order to transmit data based on signals from the load sensor, possibly via further servo controllers, to the robot arm controller 200.

[0050] A hollow shaft 8 for axial cable routing through the drive unit is firmly connected to the motor housing 1.

[0051] The drive shaft 2 is rotatably mounted on the motor housing via a rolling bearing 9 and on the output of the wave gear via a rolling bearing 10 and surrounds the hollow shaft 8.

[0052] The output of the wave gear is rotatably mounted on the gearbox housing part 1.1 of the motor housing via a roller bearing 11.

[0053] The holding brake 3 and the servo controller 6 are arranged on opposite sides of the wave gear, the servo controller 6, the drive encoder 5.1 and the output encoder 5.2 on the same side of the wave gear (left in Fig. 2).

[0054] A stator 12 of the servomotor is bonded to the motor housing 1. The motor housing 1 has a cover 1.2 for inserting the stator and the holding brake, through which the supply cables of the servomotor and the holding brake are led into the interior of the motor housing 1.

[0055] The drive unit has a temperature sensor 13 integrated in the stator 12 for detecting the temperature of the drive unit, which communicates with the servo controller 6.

[0056] In the robot arm 100, one or more of the drive units A1-A7 are configured as described above with reference to Fig. 2, wherein preferably in one or more of these drive units the motor housing 1 is connected to an end-flange-side structural member of the robot and the output of the wave gear is connected to a base-side structural member of the robot. For clarity, the motor housing 1 of drive units A1 and A2 is schematically indicated by bold dashed lines.

[0057] The drive units A1-A7, in particular their servo controllers 6, are connected to each other in series by cable, wherein the base-fixed servo controller of the drive unit A1 is connected by signal or cable to an interface 130 for communication with the robot arm control 200.

[0058] The drive shaft 2 is sealed via radial shaft seals 14, 15, the output of the wave gear via radial shaft seal 16.

[0059] The rotary bearing 11 is connected via an inner bearing cover 17.1 and an outer bearing cover 17.2.

[0060] In the present disclosure, "has an X" does not generally imply an exhaustive list, but is a shorthand for "has at least one X" and also includes "has two or more X" as well as "has Y in addition to X". Although exemplary implementations were explained in the preceding description, it should be noted that a multitude of variations are possible. Furthermore, it should be noted that the exemplary implementations are merely examples and are not intended to limit the scope of protection, applications, or structure in any way.Rather, the preceding description provides the skilled person with a guide for implementing at least one exemplary embodiment, whereby various modifications, particularly with regard to the function and arrangement of the described components, can be made without leaving the scope of protection as defined by the claims and these equivalent combinations of features.

[0061] Reference symbol list

[0062] 1 Motor housing

[0063] 1.1 Gearbox housing part

[0064] 1.2 Lid

[0065] 1.3 Mounting flange

[0066] 2 Drive shaft

[0067] 3 Holding brake

[0068] 4 Drive

[0069] 4.1 Flexspline

[0070] 4.2 Circular Spline

[0071] 5.1 Drive encoders

[0072] 5.2 Output encoder

[0073] 6 servo controllers

[0074] 7 Load sensor

[0075] 8 Hollow shaft

[0076] 9, 10 warehouses

[0077] 11 (rotary) bearings

[0078] 12 Stator

[0079] 13 Temperature sensor

[0080] 14, 15 Radial shaft seal

[0081] 16 Radial shaft seal

[0082] 17.1 inner bearing cap

[0083] 17.2 outer bearing cap

[0084] 100 robot arms

[0085] 110 base

[0086] 120 End flange

[0087] 130 interface

[0088] 200 robot arm controllers

[0089] A1, A2, A3, A4,

[0090] A5, A6, A7 drive unit; rotary drive

Claims

Patent claims 1. Modular drive unit (A1, A2, A3, A4, A5, A6, A7) for adjusting a rotary joint of a robot arm (100), the drive unit comprising: a servo motor with a motor housing (1, 1.1, 1.2, 1.3) and a drive shaft (2); a wave gear coupled to the drive shaft (4.1, 4.2); a holding brake coupled to the drive shaft (3); a drive encoder (5.1) for detecting a position of the drive shaft; an output encoder (5.2) for detecting a position of an output (4) of the wave gear; a servo controller (6) signal-connected to the drive encoder and the output encoder; a load sensor (7); and a hollow shaft (8) for axial cable passage through the drive unit.

2. Drive unit according to claim 1, characterized in that the drive shaft (2) is rotatably mounted on the motor housing (1) and / or the output (4) of the wave gear and / or surrounds the hollow shaft (8) and / or the output (4) of the wave gear is rotatably mounted on the motor housing (1, 1.2).

3. Drive unit according to one of the preceding claims, characterized in that the holding brake is an electric and / or self-closing brake and / or, in particular, is arranged at the edge of the motor housing.

4. Drive unit according to one of the preceding claims, characterized in that the holding brake and the servo controller are arranged on opposite sides of the wave gear and / or the servo controller and the drive encoder and / or output encoder are arranged on the same side of the wave gear.

5. Drive unit according to one of the preceding claims, characterized in that a stator (12) of the servomotor is materially bonded to the motor housing and / or the motor housing has a cover (1.2) for The stator and / or holding brake and / or at least one gearbox housing part (1.1) is inserted.

6. Drive unit according to one of the preceding claims, characterized in that the drive unit has a temperature sensor (13) for detecting a temperature of the drive unit.

7. Robot arm (100) with several rotary drives (A1 , A2, A3, A4, A5, A6, A7) for adjusting each of a rotary joint of the robot arm, wherein at least one of these rotary drives has a drive unit according to one of the preceding claims.

8. Robot arm according to the preceding claim, characterized in that the robot arm has a base (110) and an end flange (120) and in at least one of the drive units the motor housing is connected to an end flange-side structural member of the robot and the output of the wave gear is connected to a base-side structural member of the robot.

9. Robot arm according to one of the preceding claims 7-8, characterized in that several of the drive units are connected to each other in series by cable and / or at least one servo controller of a drive unit is connected to an interface (130) of the robot arm for communication with a robot arm controller (200) via a signal.

10. Robot arm according to one of the preceding claims 7-9, characterized in that it has at least six, in particular at least seven, rotary joints adjustable by the drive units and / or is configured as a cobot.

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