Rotary joint device for a robot and robot

Abstract

Rotary joint device (100, 200, 300, 400, 500, 600, 700) for a robot, the rotary joint device (100, 200, 300, 400, 500, 600, 700) comprising a first joint element (102, 218) and a second joint element (108, 220) with a common joint axis (116) about which the first joint element (102, 218) and the second joint element (108, 220) are rotatable together and relative to each other, characterized in that the rotary joint device (100, 200, 300, 400, 500, 600, 700) has at least one roller axis rotatable about a first roller axis on the first joint element (102, 218) radially spaced from the joint axis (116). a first roller (104, 106) arranged and rotatable with the first joint element (102, 218) about the joint axis (116), at least one second roller (110) radially spaced from the joint axis (116), rotatably arranged on the second joint element (108, 220) about a second roller axis and rotatable with the second joint element (108, 220) about the joint axis (116).112) and has at least one elastic tensile element (114, 202) that loops around at least one first roller (104, 106) and at least one second roller (110, 112).

Description

[0001] The invention relates to a rotary joint device for a robot, the rotary joint device comprising a first joint element and a second joint element with a common joint axis about which the first joint element and the second joint element are rotatable together and can be rotated relative to one another. The invention also relates to a robot.

[0002] From the document DE 10 2006 020 013 A1 a robot joint is known, with two articulated arms each connected to a joint element, wherein when the articulated arms are pivoted the joint elements slide against each other, and at least one holding element connected to one of the joint elements for holding the joint elements in contact, wherein the holding element has a deformation element in order to enable the contact between the joint elements to be released when overloads occur.

[0003] The document "Friedl, Werner & Chalon, Maxime & Reinecke, Jens & Grebenstein, Markus. (2011). FAS: A flexible antagonistic spring element for a high performance over actuated hand. 1366 -1372. 10.1109 / IROS.2011.6048177." describes an antagonistic tendon mechanism that requires little space, is adaptable, can absorb energy, and has low power consumption. The mechanism features fixed sheaves, spring-loaded sheaves, tendon-like traction devices, and winders / unwinders.

[0004] From the document DE 10 2011 105 200 A1, a leg-based robot is known with at least two legs, each leg having at least one joint with a pivotable joint element, each joint element being driven by a drive unit for generating a pivoting movement, the drive unit of each joint consisting of two drive devices, each connected to the joint element via a force transmission device, each force transmission device having an energy storage device for storing potential energy, and each drive device being drivable in two drive directions, the drive devices being operable as synergists for applying a torque in the same direction to the joint element and as antagonists for applying an opposing torque to the joint element. The energy storage device is designed as an elastic element with a non-linear characteristic curve.It is proposed to design the elastic elements as a spring, for example a compression spring or tension spring.

[0005] From the document DE 10 2016 209 639 A1 a robot hand is known with at least two fingers and two thumbs, at least one motion motor for driving each finger and each thumb, having at least one stiffness adjustment element for adjusting the stiffness of the fingers and at least one stiffness adjustment element for adjusting the stiffness of the thumbs.

[0006] From the German patent application filed on June 20, 2018 with the file number DE 10 2018 114 756.2, a rotary joint is known with a spring device for a robot, the rotary joint having a first joint element, a second joint element and a joint axis about which the first joint element and the second joint element are rotatable relative to one another, the spring device having at least one spring acting between the first joint element and the second joint element with an at least partially non-linear characteristic curve, characterized in that the at least one spring has a first clamping section, a second clamping section and a spring axis about which the first clamping section and the second clamping section are rotatable to a limited extent relative to one another, and the spring axis is arranged at least approximately coaxially to the joint axis.

[0007] From the document DE 10 2017 204 735 A1 a robot joint is known with a first segment connected to a base via a first joint, a second segment connected to the first segment via a second joint, a first braking device connected to the first joint and a first actuator and a second actuator, wherein the first actuator and the second actuator are each connected to the first segment and the second segment via a cable pull for transmitting a movement of the actuators to the first segment and / or the second segment, wherein a movement of the first actuator and / or the second actuator activates the first braking device to block the movement of the first joint and / or the second joint.

[0008] From the document DE 43 33 207 C2 an industrial robot is known with a stationary and a rotating arm, an actuator for driving the rotating arm via a rotary joint that connects the arms to one another, and with a spring that exerts a force between the stationary and the rotating arm in order to counteract a gravitational torque of the rotating arm, characterized by a device for changing the attachment point of the spring on the rotating arm in such a way that, depending on the installation position of the industrial robot and the resulting direction of the action of the gravitational force, a compensating torque generated by the spring is in each case opposite to the gravitational force.

[0009] From document US 2018 / 0085931 A1, a robot is known comprising a first link, a second link provided to be movable around the first link, and a gear device that transmits the driving force from one of the first link and the second link to the other. The gear device includes an internal gear, a flexible external gear having an external tooth portion partially meshing with the internal gear and a body portion connected to the external tooth portion in the direction of a rotation axis, and a wave generator that contacts the external gear and moves to a position where the internal gear and the external gear mesh with each other in a circumferential direction. An outer surface of the body portion has an oil-repellent part whose oil-repellent effect is higher than the oil-repellent effect of an outer surface of the external tooth portion.

[0010] From document US 2016 / 0360949 A1, a slack correction mechanism is known comprising a pulley at the distal end that is rotatable with respect to a given axis, a wire at the distal end that is wound around the pulley at the distal end, a first support member having a first base, a first friction portion around which the wire at the distal end is wound on one side, and a first biasing portion that biases the wire at the distal end in a pulling direction on one end side with respect to the first friction portion, wherein the first support member is configured to support one side of the wire at the distal end, and a second support member having a second base, a second friction portion around which the wire at the distal end is wound on the other side, and a second biasing portion that biases the wire at the distal end in a pulling direction on the other side with respect to the second friction portion.wherein the second support member is adapted to support the other side of the wire at the distal end.,

[0011] Document US 8,777,195 B2 concerns spiral torsion springs, nonlinear torsion springs, and nonlinear torsion spring assemblies. These devices are useful in damping applications, orthotic joint applications, and servo control applications.

[0012] Document US 2011 / 0167946 A1 relates to a robot joint drive device and a robot incorporating the same. The robot joint drive device operates smoothly without generating feedback. The robot includes the robot joint drive device. The robot joint drive device includes an internal gear in a ring shape, a main pulley arranged at a center of the internal gear and connected to a power source, first and second pinion gears arranged on either side of the main pulley and meshing with the internal gear, first and second pulleys respectively attached to the first and second pinion gears, first and second belts respectively connecting the main pulleys and the first and second pulleys, and tension adjustment units for adjusting the tensions of the first and second belts.

[0013] The invention is based on the object of structurally and / or functionally improving a rotary joint device mentioned above. Furthermore, the invention is based on the object of structurally and / or functionally improving a robot mentioned above.

[0014] The object is achieved with a rotary joint device having the features of claim 1. Furthermore, the object is achieved with a robot having the features of claim 14. Advantageous embodiments and / or further developments are the subject of the subclaims.

[0015] The rotary joint device can have a degree of freedom f=1. The rotary joint device can be used to connect two robot limbs of a robot to each other in a rotationally movable manner.

[0016] The first joint element may have a first connecting portion. The first connecting portion may serve for a fixed connection to a first robot link. The first connecting portion may have a flange-like shape. The first joint element may have a first receiving portion. The first receiving portion may serve to receive the first rollers. The first rollers may also be referred to as cable pulleys and / or drive pulleys. The first receiving portion may have a circular ring shape.

[0017] The second joint element may have a second connecting portion. The second connecting portion may serve for a fixed connection to a second robot link. The second connecting portion may have a flange-like shape. The second joint element may have a second receiving portion. The second receiving portion may serve to receive the second rollers. The second rollers may also be referred to as cable pulleys, tension pulleys, and / or output pulleys. The second receiving portion may have a circular ring shape.

[0018] The first receiving portion may have a circular ring shape with a smaller radius than the second receiving portion. The second receiving portion may have a circular ring shape with a larger radius than the first receiving portion. The first receiving portion and the second receiving portion may be arranged to engage one another.

[0019] The joint axis, the roller axis of the at least one first roller and the roller axis of the at least one second roller can be arranged parallel to one another.

[0020] Unless otherwise stated or the context indicates otherwise, the terms "axial," "radial," and "circumferential" refer to a direction of extension of the joint axis. "Axial" then corresponds to a direction of extension of the joint axis. "Radial" then refers to a direction perpendicular to the direction of extension of the joint axis and intersecting the joint axis. "Circumferential" then corresponds to a direction of a circular arc around the joint axis.

[0021] In the present case, “loop-shaped” refers in particular to a closed shape or a closed section of the at least one tensioning means. The at least one tensioning means can be closed all the way around. The at least one tensioning means can be closed in a ring shape. The at least one tensioning means can have a first end and a second end. The at least one tensioning means can be arranged without any crossover(s). The at least one tensioning means can form a single loop. The at least one tensioning means can be arranged with any crossover(s). The at least one tensioning means can form a plurality of loops. A crossover of the at least one tensioning means can be a crossover in an axial view. A crossover of the at least one tensioning means can be designed to be contact-free. A crossover of the at least one tensioning means can be contact-free. The at least one tensioning means can be flexible.The at least one traction element can be elastic. The at least one traction element can also be referred to as a rope.

[0022] The at least one traction means can wrap around the at least one first roller and the at least one second roller in a pre-tensioned manner. The at least one traction means can serve to non-positively connect the at least one first roller and the at least one second roller. The at least one traction means can serve to transmit force between the at least one first roller and the at least one second roller. The at least one traction means can serve to transmit torque between the first joint element and the second joint element.

[0023] The elasticity of the at least one tensioning means can result from the extensibility of the at least one tensioning means itself. The at least one tensioning means can have at least one separate elastic element to represent elasticity. The at least one elastic element can be designed as a tension spring. The at least one elastic tensioning means can serve to enable compliance of the swivel joint. The compliance can be compliance with respect to external mechanical influences on the swivel joint device. The at least one elastic tensioning means can have a linear or non-linear characteristic curve.

[0024] The rotary joint device can exhibit non-linear spring behavior. The rotary joint device can exhibit periodic spring behavior. The rotary joint device can form an overload clutch. When the first joint element and the second joint element rotate relative to one another, the rotary joint device can pass through at least one drive range, at least one dead center position, at least one over-center range, and / or at least one detent position. When the first joint element and the second joint element rotate relative to one another, the rotary joint device can periodically pass through a drive range, a dead center position, an over-center range, and a detent position.

[0025] The at least one traction means can apply a resultant force to the at least one first roller. The resultant force can comprise a pretensioning force of the at least one traction means and a force resulting from a torque introduced via the first joint element. The resultant force can cause a torque acting between the first joint element and the second joint element. Upon rotation of the first joint element and the second joint element relative to one another, the torque can periodically alternate between a positive maximum value and a negative maximum value, which can also be referred to as a minimum value, with a zero crossing.

[0026] In the at least one drive region, a positive torque can be present when the first joint element and the second joint element rotate relative to each other. In the at least one drive region, the torque can initially rise to the maximum value and then decrease again. In the at least one drive region, a torque can be transmitted between the first joint element and the second joint element using the at least one traction means.

[0027] At the dead center position, the torque curve may exhibit a zero crossing. The dead center position may be an unstable position.

[0028] In the at least one over-center region, a negative torque may be present when the first joint element and the second joint element rotate relative to each other. In the at least one over-center region, the torque may initially drop further to the minimum value and then rise again. In the at least one over-center region, the first joint element and the second joint element can be biased toward the locking position by means of the at least one traction means.

[0029] In the detent position, the torque curve may exhibit a zero crossing. The detent position may be a stable position. The detent position may be a preferred position.

[0030] The at least one first roller can be arranged with the first roller axis on a first roller axis circle. The first roller axis circle can be arranged on the first receiving section. The at least one second roller can be arranged with the second roller axis on a second roller axis circle. The second roller axis circle can be arranged on the second receiving section. The first roller axis circle can have a smaller radius than the second roller axis circle. The second roller axis circle can have a larger radius than the first roller axis circle.

[0031] The at least one first roller can be rotatable radially within the second roller axis circle about the joint axis. The at least one first roller can be rotatable radially within the second roller axis circle about the joint axis.

[0032] The pivot joint device can have a plurality of first rollers. The pivot joint device can have two, three, four, or six first rollers. The first rollers can be distributed along the first roller axis circle. The first rollers can be evenly distributed along the first roller axis circle.

[0033] The pivot joint device can have a plurality of second rollers. The pivot joint device can have two, three, or five first rollers. The second rollers can be distributed along the second roller axis circle. The second rollers can be evenly distributed along the second roller axis circle.

[0034] The pivot joint device can have a single traction element. The single traction element can be arranged in a single traction element plane. The single traction element can be distributed across multiple traction element planes. The pivot joint device can have multiple traction elements. The pivot joint device can have a first traction element and a second traction element. The traction elements can each be arranged in separate traction element planes. The traction element plane(s) can be arranged perpendicular to the joint axis. The traction element planes can be arranged parallel to one another and spaced apart from one another.

[0035] The at least one first roller can have a helical traction mechanism groove. The at least one second roller can have a helical traction mechanism groove. The at least one first roller can have a spiral traction mechanism groove with a pitch. The at least one second roller can have a spiral traction mechanism groove with a pitch. The at least one first roller can have an annular traction mechanism groove without a pitch. The at least one second roller can have an annular traction mechanism groove without a pitch.

[0036] The at least one traction means can form a single loop. The at least one traction means can form multiple loops. The at least one traction means can form four or six loops.

[0037] The at least one traction means can wrap around a single pulley with a loop. A loop of the at least one traction means can wrap around a single pulley. The at least one traction means can wrap around multiple pulleys with a loop. A loop of the at least one traction means can wrap around multiple pulleys. A loop of the at least one traction means can wrap around at least one first pulley and at least one second pulley. A loop of the at least one traction means can wrap around two first pulleys and two second pulleys. A loop of the at least one traction means can wrap around two first pulleys and three second pulleys. A loop of the at least one traction means can wrap around two first pulleys and four second pulleys. A loop of the at least one traction means can wrap around two first pulleys. A loop of the at least one traction means can wrap around three first pulleys.

[0038] The pretension of the at least one traction mechanism can be adjustable. The pivot joint device can have at least one actuator for adjusting the pretension of the at least one traction mechanism. The at least one actuator can have a motor and / or a transmission. The at least one actuator can be electrically controllable.

[0039] The robot can be a mobile robot, an autonomous robot, an industrial robot, a medical robot, a service robot, a toy robot, an exploration robot, and / or a humanoid robot. The robot can have at least a first robot limb and at least one second robot limb. The at least one first robot limb and the at least one second robot limb can be hingedly connected to one another. The at least one first robot limb and the at least one second robot limb can be connected to one another by means of the at least one rotary joint device. The first joint element can be fixedly connected to the first robot limb. The second joint element can be fixedly connected to the second robot limb.

[0040] The rotary joint device can be used in a prosthesis, in orthopedics, in the automotive industry, in agricultural machinery, in mobile drones and / or in general mechanical engineering.

[0041] In summary and in other words, the invention thus results, among other things, in an eccentric pulley coupling with non-linear periodic spring behavior.

[0042] A mechanism with nonlinear periodic spring behavior can be used, whose simultaneous function corresponds to that of an overload clutch. The mechanism can utilize the elasticity of a rope and kinematic conditions to exhibit the nonlinear periodic spring behavior. Additional common or special spring elements can be omitted, but can be connected in series with the rope if necessary.

[0043] By arranging n an Drive pulleys and n ab Output pulleys in uniform angular steps θ an and θ ab (Eq. 1) a renewed independent locking into a locking position in n inc Angle increments φ inc(Eq. 2). The rope pulleys can be arranged on one rope plane or axially along a drive axis of rotation on several rope planes.

[0044] The non-linear behavior, in particular a spring characteristic, can be variably changed by decreasing or increasing a cable pre-tension.

[0045] The risk of collision with other components is avoided.

[0046] Depending on the configuration, the spring characteristic curve can have a quadratic function in a required working range, resulting in a linear stiffness characteristic curve that is favorable for control.

[0047] The entire mechanism can be positioned rotationally symmetrically around the drive axis. This results in a more space-efficient design. Modularization is also possible. Equations: θ an , θ ab Angle steps for placing the pulleys (drive / output) nan , n ab Number of pulleys (drive / output) n inc Number of locking positions or zero positions of the torque per 180° φ inc Detent angle increment Vector of the force resultant of pulley i F i (φ) Amount of the force resultant of pulley i Direction vector of the force resultant of pulley i F S (φ) Amount of rope force α i (φ) Wrap angle of pulley i d i (φ) lever arm of the force resultant of pulley i τ(φ) total torque θan=2⋅πnan;θab=2⋅πnab ninc=πφincwithφinc={π0.5⋅(nan+nab+|nan−nab|)if mod(|nan−nab|.2)=0πnan⋅nab,else F⇀i(φ)=Fi(φ)⋅u⇀i(φ)‖u⇀i(φ)‖with Fi(φ)=Fs(φ)⋅2⋅(1+cos(π−αi(φ))) τ(φ)=∑iFi(φ)⋅di(φ)

[0048] The invention enables nonlinear compliance and overload protection. Damage is avoided. Installation space requirements are reduced. Tolerance requirements are reduced. Efforts such as design effort, adaptation effort, cost effort, and / or calibration effort are reduced. The working range is increased.

[0049] In the following, embodiments of the invention are described in more detail with reference to figures, which show schematically and by way of example: Fig. 1 a joint device with a drive-side joint element, two drive-side rollers, a driven-side joint element, two driven-side rollers and an elastic traction means wrapping around the rollers, Fig. 2 a kinematics of a joint device with a drive-side joint element, drive-side rollers, a driven-side joint element, driven-side rollers and an elastic traction means wrapping around the rollers, Fig. 3 a torque curve at the drive-side joint element when the joint elements are rotated relative to each other, Fig. 4 a joint device with a drive-side joint element, two drive-side rollers, a driven-side joint element, two driven-side rollers and an elastic traction means with adjustable pretension wrapping around the rollers, Fig. 5 preload-dependent torque curves on the drive-side joint element when the joint elements are rotated relative to each other, Fig. 6 a joint device with a drive-side joint element, three drive-side rollers, a driven-side joint element, two driven-side rollers and an elastic traction means wrapping around the rollers, Fig. 7 a joint device with a drive-side joint element, four drive-side rollers, a driven-side joint element, two driven-side rollers and an elastic traction means wrapping around the rollers, Fig. 8 a joint device with a drive-side joint element, six drive-side rollers, a driven-side joint element, two driven-side rollers and two elastic traction means wrapping around the rollers in separate traction center planes, Fig. 9 a joint device with a drive-side joint element, two drive-side rollers, a driven-side joint element, three driven-side rollers and an elastic traction means wrapping around the rollers over several traction center planes and Fig. 10 a joint device with a drive-side joint element, three drive-side rollers, a driven-side joint element, five driven-side rollers and an elastic traction means wrapping around the rollers over several traction center planes,

[0050] Fig. 1 shows a joint device 100 with a first joint element 102, two first rollers 104, 106, a second joint element 108, two second rollers 110, 112 and an elastic tension means 114 that wraps around the rollers 104, 106, 110, 112 in a pre-tensioned manner.

[0051] The traction means 114 serves for the force-locking connection of the first rollers 104, 106 and the second rollers 110, 112 and thus for the force transmission between the first rollers 104, 106 and the second rollers 110, 112 and for the torque transmission between the first joint element 102 and the second joint element 108.

[0052] The rotary joint device 100 serves, for example, to articulate two robot limbs of a robot. In this case, the first joint element 102 is firmly connected to a first robot limb, and the second joint element 108 is firmly connected to a second robot limb. In this case, the first joint element 102 serves as the drive, and the second joint element 108 serves as the output.

[0053] The first joint element 102 and the second joint element 108 have a common joint axis 116 about which the first joint element 102 and the second joint element 108 can rotate together and can be rotated relative to one another. The first rollers 104, 106 are arranged on the first joint element 102 diametrically opposite one another from the joint axis 116, each radially spaced equally apart, and are each rotatable about a first roller axis. The second rollers 110, 112 are arranged on the second joint element 108 diametrically opposite one another from the joint axis 116, each radially spaced equally apart, and are each rotatable about a second roller axis.

[0054] The first rollers 104, 106 are arranged with their roller axes on a first roller axis circle 118. The second rollers 110, 112 are arranged with their roller axes on a second roller axis circle 120. The first roller axis circle 118 has a radius smaller than the second roller axis circle 120 such that when the first joint element 102 and the second joint element 108 are rotated relative to one another, the first rollers 104, 106 can rotate radially within the second roller axis circle around the joint axis 118.

[0055] In the following, a rotation of the first joint element 102 with the second joint element 108 stationary in the direction of rotation angle φ is considered and in particular Fig. 2, which shows a kinematics of the joint device 100. Fig. 3 shows a torque curve 122 occurring at the first joint element 102, wherein a deflection φ is plotted on an x-axis and a torque τ is plotted on a y-axis.

[0056] Starting from a locking position at a deflection φ = 0, in which the first roller axes, the second roller axes and the joint axis 118 lie on a common line, first, as in Fig. 1, a drive range is passed through until a dead center position is reached at a deflection of φ = π / 2. Subsequently, an over-dead center range is passed through until the detent position is reached again at a deflection of φ = π.

[0057] The traction means 114 applies a resulting force to the first rollers 104, 106 F⇀i(φ), which comprises a pre-tensioning force of the traction means 114 and a force resulting from a torque introduced via the first joint element 102. In the drive range, the torque τ increases from a value τ = 0 in the locking position to a maximum value τ max and subsequently drops back to a value τ = 0 in the dead center position. In the over-dead center range, the torque τ initially drops further from a value τ = 0 in the dead center position to a minimum value -τ max and subsequently rises again to a value τ = 0 in the locking position.

[0058] In the drive area, a predetermined maximum torque can be transmitted from the first joint element 102 to the second joint element 108 using the traction mechanism 114. If the maximum torque is exceeded, the unstable dead center position is passed through and the locking position is initially assumed as the preferred position. Upon further application of torque to the first joint element 102, torque is again transmitted to the second joint element 108 in the drive area. The rotary joint device 100 thus exhibits a nonlinear periodic spring behavior and forms an overload clutch.

[0059] The rotary joint device 100 has n an = 2 drive rollers, n ab = 2 output rollers, n inc = 2 locking positions per 180° and one locking angle increment φ inc = 90°.

[0060] Fig. 4 shows a joint device 200 in which the pretension of the traction means 202 is adjustable. The traction means 202 has a first end 204 and a second end 206. The joint device 200 has an actuator 208. The first end 204 is fixedly arranged, and the second end 206 is connected to the actuator 208 for adjusting the pretension of the traction means 202. A spring element 209 is arranged between the actuator 208 and the second end 206 of the traction means 202.

[0061] Fig. Figure 5 shows, depending on the pretension of the traction device 202, different torque curves 210, 212, 214, 216 when the first joint element 218 is rotated in the direction of rotation angle φ and the second joint element 220 is stationary, with a deflection φ being plotted on an x-axis and a torque τ being plotted on a y-axis. With increasing pretension of the traction device 202, the maximum value τ max and the minimum value -τ max ·

[0062] In addition to the joint device 200, particular attention is drawn to Fig. 1 to Fig. 3 and the corresponding description.

[0063] Fig. 6 shows a joint device 300 with n an = 3 drive rollers, n ab = 2 output rollers, n inc = 6 locking positions per 180° and one locking angle increment φ inc = 30°. In addition to the joint device 300, particular attention is paid to Fig. 1 to Fig. 3 and the corresponding description.

[0064] Fig. 7 shows a joint device 400 with n an = 4 drive rollers, n ab = 2 output rollers, n inc = 4 locking positions per 180° and one locking angle increment φ inc = 45°. In addition to the joint device 400, particular attention is paid to Fig. 1 to Fig. 3 and the corresponding description.

[0065] Fig. 8 shows a joint device 500 with n an= 6 drive rollers arranged in two traction center planes, n ab = 2 output rollers, n inc = 6 locking positions per 180° and one locking angle increment φ inc = 30°. The traction mechanism is guided over the two traction center planes. In addition to the joint device 500, in particular Fig. 1 to Fig. 3 and the corresponding description.

[0066] Fig. 9 shows a joint device 600 with n an = 2 drive rollers, n ab = 3 output rollers, n inc = 6 locking positions per 180° and one locking angle increment φ inc = 30°. The traction mechanism is guided over three traction center planes. In addition to the joint device 600, in particular Fig. 1 to Fig. 3 and the corresponding description.

[0067] Fig. 10 shows a joint device 700 with n an = 3 drive rollers, n ab = 5 output rollers, n inc= 15 locking positions per 180° and one locking angle increment φ inc = 12°. The traction mechanism is guided over three traction center planes. In addition to the joint device 700, in particular Fig. 1 to Fig. 3 and the corresponding description.

[0068] The Fig. The joint device 100 shown in Figure 1 forms a serially elastic actuator based on an effect based on the kinematics of the mechanism and the elasticity of the traction means 114. Here, the first joint element 102 initiates a torque on the eccentric first rollers 104, 106, which are firmly connected to the first joint element 102. With the second joint element 108 stationary, a transverse force is thereby transmitted through the first rollers 104, 106 into the traction means 114. The traction means 114 thereby experiences an elongation Δl(φ) and an increase in the traction means tension F S (φ) in addition to the already existing prestress F S0of the traction means 114 by the second rollers 110, 112. With progressive rotation φ of the first joint element 102, the lever arm d decreases i (φ) of the force resultant F⇀i(φ) of the i-th first roller to the joint axis 116, but the force resultant grows in a non-linear relationship to the lever arm, see Fig. 2. This effect leads to the above-mentioned non-linear periodic spring behavior of the entire system and repeats itself periodically in the Fig. 1 to Fig. 3 shown embodiment with two eccentric first rollers 104, 106 every 180°. Further exemplary embodiments with more than two first rollers 104, 106 (drive) and / or second rollers (output) are Fig. 6 to Fig. 10.

[0069] Fig. 4 shows the same mechanism Fig. 1, but designed as a variable stiffness actuator. The variability of the stiffness is achieved by an additional actuator 208 for adjusting the tension of the traction mechanism. In addition, it is possible to modify the tensile stiffness of the traction mechanism 202 by an additional spring element 209. This is also possible in the mechanism according to Fig. 1 possible.

[0070] Finally, in all designs, depending on the geometric specifications, the preload of the traction device(s) and eccentric roller configurations, a resulting torque τ(φ) is generated according to (Eq. 4).

[0071] "May" refers in particular to optional features of the invention. Accordingly, there are also further developments and / or embodiments of the invention that additionally or alternatively comprise the respective feature(s). Reference symbol 100 joint device 102 first joint element 104 first role 106 first role 108 second joint element 110 second roll 112 second role 114 traction devices 116 Joint axis 118 first roller axis circle 120 second roller axis circle 122 Torque curve 200 joint device 202 traction devices 204 first end 206 second end 208 Actuator 209 spring element 210 torque curve 212 Torque curve 214 Torque curve 216 Torque curve 218 first joint element 220 second joint element 300 joint device 400 joint device 500 joint device 600 joint device 700 joint device

Claims

[1] A rotary joint device (100, 200, 300, 400, 500, 600, 700) for a robot, the rotary joint device (100, 200, 300, 400, 500, 600, 700) comprising a first joint element (102, 218) and a second joint element (108, 220) with a common joint axis (116) about which the first joint element (102, 218) and the second joint element (108, 220) are rotatable together and rotatable relative to one another, characterized bythat the rotary joint device (100, 200, 300, 400, 500, 600, 700) comprises at least one first roller (104, 106) which is radially spaced from the joint axis (116), is arranged on the first joint element (102, 218) so as to be rotatable about a first roller axis and is rotatable with the first joint element (102, 218) about the joint axis (116), at least one second roller (110, 112) which is radially spaced from the joint axis (116), is arranged on the second joint element (108, 220) so as to be rotatable about a second roller axis and is rotatable with the second joint element (108, 220) about the joint axis (116), and at least one elastic element which loops around the at least one first roller (104, 106) and the at least one second roller (110, 112). traction means (114, 202). [2] Swivel joint device (100, 200, 300, 400, 500, 600, 700) according to claim 1, characterized bythat the at least one first roller (104, 106) is arranged with the first roller axis on a first roller axis circle (118), the at least one second roller (110, 112) is arranged with the second roller axis on a second roller axis circle (120), the first roller axis circle (118) has a smaller radius and the second roller axis circle (120) has a larger radius. [3] Swivel joint device (100, 200, 300, 400, 500, 600, 700) according to claim 2, characterized by that the at least one first roller (104, 106) is rotatable radially within the second roller axis circle (120) about the joint axis (116). [4] Swivel joint device (100, 200, 300, 400, 500, 600, 700) according to at least one of claims 2 to 3, characterized bythat the rotary joint device (100, 200, 300, 400, 500, 600, 700) has a plurality of first rollers (104, 106) distributed on the first roller axis circle (118) and / or a plurality of second rollers (110, 112) distributed on the second roller axis circle (120). [5] Swivel joint device (100, 200, 300, 400, 600, 700) according to at least one of claims 1 to 4, characterized by that the rotary joint device (100, 200, 300, 400, 600, 700) has a single traction means (114, 202) arranged in a traction center plane. [6] Swivel joint device (600, 700) according to at least one of claims 1 to 4, characterized by that the rotary joint device (600, 700) has a single traction means (114, 202) distributed over several traction means planes. [7] Swivel joint device (600, 700) according to claim 6, characterized bythat the at least one first roller (104, 106) and / or the at least one second roller (110, 112) have / have a helically extending traction means groove. [8] Swivel joint device (500) according to at least one of claims 1 to 4, characterized by that the rotary joint device (500) has a plurality of traction means (114, 202) each arranged in separate traction center planes. [9] Swivel joint device (100, 200, 300, 400, 500) according to at least one of claims 1 to 8, characterized by that the at least one traction means (114, 202) forms a single loop. [10] Swivel joint device (600, 700) according to at least one of claims 1 to 8, characterized by that the at least one traction means (114, 202) forms several loops. [11] Swivel joint device (600, 700) according to at least one of claims 1 to 10, characterized by that the at least one traction means (114, 202) wraps around a single roller with a loop. [12] Swivel joint device (100, 200, 300, 400, 500, 600, 700) according to at least one of claims 1 to 11, characterized by that the at least one traction means (114, 202) wraps around several rollers (104, 106, 110, 112) with a loop. [13] Swivel joint device (200) according to at least one of claims 1 to 12, characterized by that a pretension of the at least one traction means (114, 202) is adjustable. [14] Robots, characterized by that the robot has at least one rotary joint device (100, 200, 300, 400, 500, 600, 700) according to at least one of claims 1 to 13.

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