WO2023194707A1 - Accouplement de joint - Google Patents

Accouplement de joint Download PDF

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Publication number
WO2023194707A1
WO2023194707A1 PCT/GB2023/050867 GB2023050867W WO2023194707A1 WO 2023194707 A1 WO2023194707 A1 WO 2023194707A1 GB 2023050867 W GB2023050867 W GB 2023050867W WO 2023194707 A1 WO2023194707 A1 WO 2023194707A1
Authority
WO
WIPO (PCT)
Prior art keywords
joint
joint coupling
resiliently compressible
formations
limb
Prior art date
Application number
PCT/GB2023/050867
Other languages
English (en)
Inventor
Michele Camerlengo
Jindong LIU
Original Assignee
Precision Robotics Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Precision Robotics Limited filed Critical Precision Robotics Limited
Publication of WO2023194707A1 publication Critical patent/WO2023194707A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J13/00—Controls for manipulators
    • B25J13/02—Hand grip control means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J17/00—Joints
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/30—Surgical robots
    • A61B34/37—Master-slave robots
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B34/00—Computer-aided surgery; Manipulators or robots specially adapted for use in surgery
    • A61B34/70—Manipulators specially adapted for use in surgery
    • A61B34/74—Manipulators with manual electric input means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
    • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
    • B25J19/00—Accessories fitted to manipulators, e.g. for monitoring, for viewing; Safety devices combined with or specially adapted for use in connection with manipulators
    • B25J19/0091—Shock absorbers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D7/00—Slip couplings, e.g. slipping on overload, for absorbing shock
    • F16D7/002—Slip couplings, e.g. slipping on overload, for absorbing shock the torque being transmitted and limited by yielding of an elastomeric race

Definitions

  • This invention relates to a joint coupling for a movable joint, and more particularly although not exclusively, to a joint coupling for a movable joint forming part of an articulated manipulator which, in turn, forms part of a master controller.
  • Known remote-control systems comprise a master controller, situated locally to an operator, and a slave device, situated remotely to the operator, wherein the system allows the slave device to be manipulated by the operator at a distance.
  • a slave device may be used to carry out a minimally invasive surgical procedure in which direct manipulation of surgical tools by a surgeon is not possible due to restricted access to the patient’s internal tissues and organs.
  • Other examples may include military applications such as bomb disposal, emergency service applications such as search and rescue, and scientific research activities such as carrying out tasks in inhospitable environments (e.g., vacuums or high levels of reactivity) where direct manipulation could be hazardous or impossible.
  • a master controller In remote robotic surgery, a master controller is needed for transferring a surgeon’s hand motion to a remote robotic instrument motion.
  • Known master controllers comprise two articulated manipulator arms for bimanual (two-handed) control that allows the control of a robotic instrument with each hand simultaneously.
  • the surgeon holds a handle at the end of each manipulator arm via fingers or the whole hand and moves the handle to control the robotic instruments while he or she monitors the robotic instruments via an endoscope image, for example.
  • the manipulator arms can be classified into two categories: active and passive.
  • An active manipulator arm has a motor to drive each joint and these motors allow the pose of the whole manipulator arm to be maintained regardless of whether the surgeon continues to hold the handle of the manipulator arm. This means that the surgeon can let go of the manipulator arm without risk of the manipulator arm dropping under the effect of gravity and a corresponding motion being replicated by the robotic instrument with the potential of harming a patient.
  • the risk associated with dropping a manipulator arm handle is reduced and the surgeon may readily pause control of the robotic instrument to carry out a different task.
  • passive manipulator arms measure the position of each joint in the arm but do not actively drive each joint. This means that the manipulator arm will return to a ‘floppy’ state when the surgeon’s hand releases the handle, and the manipulator arm will drop under the effect of gravity.
  • a passive manipulator arm returns to a floppy state when released by the operator
  • known passive manipulator arms are lockable.
  • the manipulator arms are configured so that each joint in the manipulator arm is locked when the handle is released and are unlocked only when an operator re-grasps the handle or otherwise triggers disengagement of the locks.
  • a joint coupling for a movable joint comprising: a first body comprising a first formation; a second body movable relative to the first body, the second body comprising a second formation slidably engageable with the first formation; a cavity formed by one or more of the first and second bodies, the cavity having a length along which at least one of the first and second formations can travel on movement of the second body relative to the first body; and first and second resiliently compressible members received within the cavity in a partially compressed configuration, the first and second resiliently compressible members separated from one another by the first and second formations thereby biasing the first and second bodies towards a balanced configuration in which the first and second formations are aligned with one another.
  • such a joint coupling may be applied to a movable joint comprising a first limb and a second limb that are movable with respect to one another and, also, lockable in a particular configuration depending on the intent of a user. More specifically, the first body of the joint coupling may be coupled to the first limb and the second body may be coupled to the second limb.
  • first and second bodies will hold the balanced configuration, in which the first and second formations are aligned or, at least, substantially aligned bearing in mind manufacturing tolerances. This means the movable joint will hold its intended position.
  • first and second bodies will continue to hold the balanced configuration.
  • This rigidity of the joint when small forces are being applied is useful because it prevents a locked movable joint from moving away from its intended position at the slightest touch or merely due to the effect of gravity, for example.
  • the rigidity of the joint coupling also means that when the movable joint is unlocked and being operated by a user, no backlash is introduced to the movable joint by the presence of the joint coupling.
  • the movable joint will be moved accordingly.
  • a movable joint may be coupled in such a way that, when locked or otherwise immobilised in a particular configuration, the movable joint remains rigid against small forces acting on it but is also resiliently flexible when larger forces are applied.
  • each of the first and second resiliently compressible members may have a predefined restoring force such that an applied force exceeding the predefined restoring force of the first or second resiliently compressible member is required to cause further compression of the respective resiliently compressible member to move the first and second bodies away from the balanced configuration.
  • the predefined restoring force of each of the first and second resiliently compressible members may depend on the size, material and/or configuration of that resiliently compressible member. Accordingly, through selection of each resiliently compressible member, the predefined restoring force may be defined such that a suitable amount of force is required to further compress the respective resiliently compressible member. For example, the predefined restoring force may be defined to ensure that the weight of an articulated manipulator comprising the joint coupling is not sufficient to cause a force that could further compress the respective resiliently compressible member. In some embodiments of the invention, the predefined restoring force may be the same for each of the first and second resiliently compressible members in order that the joint coupling is equally resilient to movement of the second body relative to the first body (or vice versa) in either direction.
  • the predefined restoring force may be different for each of the first and second resiliently compressible members in order that the joint coupling acts differently depending on the direction of a force applied to it.
  • the predefined restoring force of each resiliently compressible member may be defined to substantially eliminate the effect of gravity on the movable joint.
  • the first and second formations may be any shape suitable to allow the first and second resiliently compressible members to exert a force against them, thereby biasing the first and second formations towards alignment with one another.
  • Each of the first and second formations may comprise first and second faces wherein each of the first and second resiliently compressible members may be abuttable against the respective face of each of the first and second formations.
  • the abutment of each of the first and second resiliently compressible members against the respective face of one or both of the first and second formations may ensure that the resiliently compressible member reliably exerts a force against at least one of the first and second formations.
  • first faces of the first and second formations may be aligned with one another and the second faces of the first and second formations may also be aligned with one another.
  • the first and second formations may be interlockable, each having at least one portion which overlaps at least one portion of the other formation. This may ensure that each of the first and second resiliently compressible members is abuttable against the respective face of each of the first and second formations with there being a plurality of contact points between the resiliently compressible member and the formation face.
  • the interlockable first and second formations may, further, be configured such that there is at least three separate contact points between each resiliently compressible member and the respective face of each formation and, optionally, such that the at least three contact points are substantially evenly spaced apart from one another.
  • each resiliently compressible member may abut the respective face of each formation stably and reliably, with reduced risk of the resiliently compressible member deforming and either slipping past the face of a formation or becoming jammed within the cavity.
  • the second body may be rotatably movable relative to the first body and the first and second formations may be configured to slide past one another tangentially.
  • the joint coupling may be used to couple a first limb to a second limb which pivots relative to the first limb (similarly to an elbow or a hinge).
  • the joint coupling may also be used to couple a rotatable joint in which a first limb is axially rotatable relative to a second limb (similarly to a doorknob).
  • the second body may be linearly movable relative to the first body and the first and second formations may be configured to slide past one another translationally.
  • Such embodiments of the invention may be useful for coupling a linearly movable joint in which a first limb moves telescopically relative to a second limb.
  • torque may be used with respect to embodiments of the inventions that are rotatably movable and the term “force” may used with respect to embodiments of the invention that are linearly movable. Further, these terms are essentially interchangeable within the context of this invention, particularly in terms of the overall functionality.
  • each of first and second resiliently compressible members may comprise a spring or elastomeric block.
  • Specific characteristics of the spring or elastomeric block may be selected to define the restoring force of that resiliently compressible member.
  • characteristics such as the number of coils may be adapted to vary the spring’s resilience to compression.
  • the material composition may be selected to provide the desired resilience to compression.
  • the elastomeric block may comprise one or more of the following elastomeric materials: rubber, silicone, nitrile, vinyl and neoprene.
  • the first and second bodies may comprise a plurality of first and second formations
  • the joint coupling may comprise a respective plurality of cavities and first and second resiliently compressible members.
  • the plurality of first resiliently compressible members may work in unison to bias the first and second formations towards alignment with respect to one direction of movement of the second body relative to the first body.
  • the plurality of second resiliently compressible members may work in unison to bias the first and second formations towards alignment with respect to an opposite direction of movement of the second body relative to the first body.
  • first and second resiliently compressible members By incorporating a plurality of first and second resiliently compressible members it is therefore possible to increase the joint coupling’s overall resilience to movement, particularly if only a small range of movement is to be allowed by the joint coupling.
  • the joint coupling may further comprise a third body coupled to the first body, wherein: the first body may comprise a first gripping surface and the third body may comprise a second gripping surface; and the first and second gripping surfaces may be configured to grip a limb of a movable joint with a predefined gripping force such that an applied force exceeding the predefined gripping force is required to move the joint coupling relative to the limb of the movable joint.
  • the joint coupling may be linearly movable relative to the limb of the movable joint. In other such embodiments, the joint coupling may be rotatably movable relative to the limb of the movable joint.
  • predefined gripping force may be used interchangeably with the term ‘predefined gripping torque’ as appropriate for the type of movement available.
  • the first and second gripping surfaces may be configured to grip a limb of a movable joint with a predefined gripping torque such that an applied torque exceeding the predefined gripping torque is required to rotate the joint coupling relative to the limb of the movable joint.
  • a joint coupling may be applied to a movable joint comprising a first limb and a second limb that are movable with respect to one another and, also, lockable in a particular configuration depending on the intent of a user. More specifically, the first body of the joint coupling may be movably coupled to the first limb by way of the first and third bodies gripping the first limb. Meanwhile, the second body may be coupled to the second limb.
  • the joint coupling will either remain rigid or flex, as described above.
  • the relationship between the first and second limbs essentially mirrors the relationship between the first and second bodies.
  • the movable joint is rigid when the joint coupling is rigid but when the joint coupling flexes, so too does the movable joint.
  • the first and third bodies may lose traction against the first limb. Once traction is lost, the entire joint coupling is movable relative to the first limb and, therefore, the second limb is also movable relative to the first limb.
  • Traction between the first and third bodies and the limb may be restored once the force being applied reduces below the predefined gripping force.
  • any displacement of the second limb relative to the first limb which occurred while traction had been lost may not be recovered. Therefore, if the movable joint forms part of a manipulator used to remotely control a robot, the robot may require recalibration to a new configuration of the manipulator. That being said, the surgical robot may be returned to an operable state through recalibration much more quickly than would be the case if an excessive force applied to the manipulator has caused it to break.
  • the joint coupling may further comprise a tightening mechanism adjustably coupling the third body to the first body.
  • the tightening mechanism may be tightened or loosened to adjust the predefined gripping force.
  • the tightening mechanism may be any mechanism suitable to adjust the positioning of the third body relative to the first body and, in turn, adjust how tightly the first and third bodies grip the limb.
  • the tightening mechanism may comprise a nut and screw adjustably receivable within the nut.
  • the tightening mechanism may comprise a biasing element, such as a spring, biasing the third body towards the first body.
  • the resilience to compression of the biasing element may, at least partially, contribute to the predefined gripping force. That is, the greater the resilience to compression of the biasing element, the greater the associated predefined gripping force will be.
  • the friction factor between the first and second gripping surfaces and the limb of the movable joint may also contribute to the predefined gripping force such that the greater the friction factor, the greater the predefined gripping force.
  • the predefined gripping force may be considered as the effect that results from the combination of the resilience to compression of the biasing element and the friction factor between the first and second gripping surfaces and the limb. Or, more simply, the predefined gripping force may be considered as equivalent to the force required to overcome the friction caused by the biasing element and the friction factor between the first and second gripping surfaces and the limb.
  • the predefined gripping force may be greater than the predefined restoring force so that the second body may recoverably move relative to the first body before the joint coupling is irrecoverably moved relative to the limb of the movable joint.
  • the joint coupling will only slip relative to the limb if a force being applied to it is large enough that the integrity of the movable joint is at risk despite it complying to the force which is being applied to some degree.
  • each of the first and second resiliently compressible members is still further compressible with a force greater than the predetermined gripping force. This prevents a maximum amount of possible movement between the first and second bodies being reached prior to the joint coupling being able to slip relative to the limb of the movable joint. In other words, it prevents there being an intermediate range of forces, between the predefined restoring force and the predefined gripping force, which could cause the joint to become rigid, as this would expose the joint to increased risk of failure.
  • an articulated manipulator comprising: a first limb; a second limb; and a joint coupling, according to the first aspect of the invention, coupling the second limb to the first limb.
  • the joint coupling may be configured to suit the specific characteristics of the first and second limbs which it is to couple.
  • the joint coupling may be configured to be suitable for the required mode of movement, i.e., pivotal rotation, axial rotation or linear translation.
  • the joint coupling may also be configured to be a suitable size for the associated limbs.
  • the predefined restoring force and/or the predefined gripping force may also be defined for the specific application in which the movable joint is to be used.
  • an articulated manipulator for a surgical robot controller comprising a movable joint according to the second aspect of the invention.
  • the articulated manipulator may be more robust than known articulated manipulators lacking a joint coupling that allows joints of the articulated manipulator to comply to an applied force which might otherwise cause failure of the joint.
  • Figures 1 and 2 are schematic representations of a joint coupling according to an embodiment of the first aspect of the invention
  • Figures 3 and 4 show the joint coupling of Figures 1 and 2 when moved to a different configuration
  • Figure 5 is a schematic representation of a master controller comprising a pair of articulated manipulators according to the third aspect of the invention.
  • Figure 6 is a schematic representation of a movable joint according to the second aspect of the invention
  • Figure 7 shows a cross-sectional view of the movable joint shown in Figure 6;
  • Figure 8 shows a cross-sectional view of the movable joint shown in Figure 6 when moved to a different configuration to that shown in Figure 7;
  • Figure 9 shows a further cross-sectional view of the movable joint shown in Figure 6;
  • Figure 10 shows another cross-sectional view of the movable joint shown in Figure 6;
  • Figure 11 is a schematic representation of a third body forming part of the movable joint shown in Figure 6;
  • Figure 12 is a schematic representation of a first body forming part of the movable joint shown in Figure 6;
  • Figure 13 is a graphical representation of the torque required to rotate the movable joint shown in Figure 6;
  • Figures 14 and 15 are schematic representations of a joint coupling according to another embodiment of the first aspect of the invention.
  • Figures 16 and 17 show the joint coupling of Figures 14 and 15 when moved to a different configuration.
  • a joint coupling according to an embodiment of the invention is designated generally by the reference numeral 2.
  • the joint coupling 2 comprises a first body 4, comprising a first formation 10, and a second body 6, comprising a second formation 12.
  • the second body 6 is movable relative to the first body 4, and vice versa, and the second formation 12 is slidably engageable with the first formation 10 whereby movement of the first and second bodies 4, 6 relative to one another causes the first and second formations 10, 12 to slide past one another.
  • the second body 6 is linearly movable relative to the first body 4, and vice versa, and the first and second formations 10, 12 are configured to slide past one another in a translational sense.
  • the joint coupling 2 may therefore be used to couple a translational or telescopic style of joint, for example.
  • the joint coupling 2 further comprises a cavity 14.
  • the cavity is formed by a combination of the first and second bodies 4, 6 wherein the shape of the first body 4, in particular, defines a first end 15 and a second end 16 of the cavity 14.
  • the first and second formations 10, 12 each comprise a first face 22, facing towards the first end 15 of the cavity 14, and a second face 24, facing towards the second end 16.
  • the cavity 14 has a length that extends from the first end 15 to the second end 16.
  • the first and second formations 10, 12 each extend into the cavity 14, transversely to the length of the cavity 14.
  • the joint coupling 2 also comprises first and second resiliently compressible members 18, 20, each of which is received within the cavity 14 in a partially compressed configuration.
  • first resiliently compressible member 18 extends between, and abuts against, the first end 15 of the cavity 14 and the first face 22 of the first and second formations 10, 12 while the second resiliently compressible member extends between, and abuts against, the second end 16 of the cavity 14 and the second face 24 of the first and second formations 10, 12.
  • first and second resiliently compressible members 18, 20 are partially compressed means that each of the resiliently compressible members 18, 20 exert a force against the first and second formations 10, 12. Therefore, although the first and second bodies 4, 6 are movable relative to one another, they are biased towards a balanced configuration in which the first and second formations 10, 12 are aligned with one another, as shown in Figures 1 and 2.
  • each resiliently compressible member 18, 20 is a spring having a predefined restoring force.
  • the resiliently compressible members 18, 20 are each configured such that an applied force exceeding the predefined restoring force of the respective resiliently compressible member 18, 20 is required to cause further compression of that resiliently compressible member 18, 20 from the configuration in which it is shown in Figures 1 and 2.
  • the joint coupling 2 will remain rigid, i.e., the first and second bodies 4, 6 will remain in the balanced configuration.
  • a force exceeding the predefined restoring force is applied to the first body 4 and/or the second body 6, the first and second bodies 4, 6 will be moved away from the balanced configuration.
  • the first resiliently compressible member 18 will exert sufficient force on the second formation 12 to move it back along the length of the cavity and into alignment with the first formation 10.
  • the second body 6 will, therefore, be moved so that the first and second bodies 4, 6 are back in the balanced configuration shown in Figures 1 and 2.
  • the joint coupling 2 inherently restores to the balanced configuration allows a movable joint to ‘flex’ if a sufficiently large force is applied to it without permanently losing its intended configuration.
  • Stresses associated with a force being applied to the movable joint are essentially absorbed by one of the resiliently compressible members 18, 20, thereby reducing the likelihood of breakage or failure occurring stresses accumulating within a fragile or vulnerable component.
  • a master controller 60 for a remotely operated surgical robot (not shown) comprises a pair of articulated manipulators 50.
  • Each manipulator 50 comprises a movable joint 40, specifically a rotatably movable joint.
  • Each movable joint 40 allows rotation between a first limb 42 and a second limb 44.
  • each manipulator 50 is passive and each movable joint 40 is lockable in order that the manipulators 50 may be locked in a particular configuration when not being operated by a user.
  • each movable joint 40 comprises a gear 46 coupled to the first limb 42 and a locking latch 47 coupled to the second limb 44 (not shown in Figure 6 in order to reveal the internal components).
  • the locking latch 47 may be engaged with the gear 46, thereby preventing the second limb from rotating, about a joint axis 48, relative to the first limb 42.
  • the locking latch 47 may be disengaged so that first and second limbs can rotate relative to one another about the joint axis 48.
  • the gear 46 is coupled to the first limb 42 via a joint coupling 102 similar to the joint coupling 2 shown in Figures 1 to 4 except that the second body 106 is rotatably movable relative to the first body 104 rather than linearly movable. Further, in this embodiment of the invention, the gear 46 and the second body 106 are integral.
  • the manipulators may be active.
  • the second limb may comprise a motor-driven gear which is always in engagement with the gear of the movable joint.
  • the motor-driven gear may be rotated so that it travels around the gear of the movable joint.
  • each joint coupling may function in exactly the same way as the joint coupling 102, described in more detail below.
  • a cavity 114 is formed by a combination of the first and second bodies 104, 106 whereby the cavity 114 extends in a tangential fashion around the joint axis 48 (shown in Figure 6), rather than in a linear fashion like the cavity 14 shown in Figures 1 to 4.
  • the cavity 114 also differs from the cavity 14 in that it is the shape of the second body 106, rather than the first body 104, which defines a first end 115 and a second end 116 of the cavity 114.
  • the length of the cavity 114 is therefore defined by the second body 106.
  • the joint coupling 102 also comprises first and second resiliently compressible members 118, 120 separated from one another by the first and second formations 110, 112. As with the embodiment of the invention shown in Figures 1 to 4, each of first and second resiliently compressible members 118, 120 is received within the cavity 114 in a partially compressed configuration so that the first and second bodies 104, 106 are biased towards a balanced configuration as shown in Figure 7.
  • the resiliently compressible members 118, 120 are also configured to each have a predefined restoring force such that an applied force exceeding the predefined restoring force of the respective resiliently compressible member 118, 120 is required to cause further compression of that resiliently compressible member 18, 20 from the configuration in which it is shown in Figure 7.
  • both the joint coupling 102 and the locked movable joint 40 will remain rigid, i.e., the first and second bodies 104, 106 will remain in the balanced configuration.
  • a torque is being applied to the second limb 44 so that a force greater than the predefined restoring force is being applied to the first resiliently compressible member 118.
  • the torque is being applied in a clockwise direction (as viewed on the page).
  • the torque is therefore large enough to cause the first formation 110 to travel along the length of the cavity 114, and thus, to cause the second body 106 to rotate relative to the first body 104.
  • the first resiliently compressible member 118 will exert sufficient force on the first formation 110 to move it (relative to the second body 106) back along the length of the cavity 114 and into alignment with the second formation 112.
  • the first and second bodies 104, 106 will, therefore, be restored to the balanced configuration shown in Figure 7.
  • first and second formations 110, 112 are interlockable.
  • the first and second formations 110, 112 overlap one another with a labyrinthine structure as they fit together.
  • first resiliently compressible member 118 may abut against the first face 122 of each of the first and second formations 110, 112 at a plurality of contact points 126.
  • second resiliently compressible member 120 contacting the second face of each of the first and second formations 110, 112, although this is shown not in Figure 9.
  • the first and second formations 110, 112 are configured to interlock in such a way that each resiliently compressible member 118, 120 contacts the respective face of each formation 110, 112 with three separate contact points 126. Further, the three contact points are substantially equally spaced apart from one another. Each resiliently compressible member 118, 120 may therefore abut against each formation 110, 112 in a balanced and stable manner, even if the formations 110, 112 are not aligned with one another.
  • the joint coupling 102 further comprises a third body 108 coupled to the first body 104.
  • the first body 104 comprises a first gripping surface 136
  • the third body 108 comprises a second gripping surface 138 wherein the first and second gripping surfaces 136, 138 are configured to grip the first limb 42 with a predefined gripping torque.
  • the predefined gripping torque is defined by a combination of a tightness with which the first and third bodies are coupled and a friction factor between the first and second gripping surfaces 136, 138 and the first limb 42.
  • the joint coupling 102 further comprises a tightening mechanism 130 coupling the third body 108 to the first body 104 with an adjustable degree of tightness.
  • the tightening mechanism comprises a screw 134 and a nut 135 which may be tightened or loosened by applying a torsional force to the screw 134.
  • the tightening mechanism further comprises a biasing element 132, which is a spring in this embodiment of the invention, biasing the third body 108 towards the first body 108. Accordingly, the tightness of the coupling of the third and first bodies is defined by the tightness of the screw 134 and nut 135 as well as the resilience against compression of the biasing element 132.
  • Figure 13 shows a graph 100 representing the possible rotation of the second limb 44 relative to the first limb 42 while the second limb 44 is in locked engagement with the joint coupling 102 via the gear 46 and locking latch 47.
  • the predefined restoring force of both resiliently compressible members is 10 N and the predefined gripping torque with which the first limb 42 is gripped by the first and second gripping surfaces 36, 38 is 20 N. If less than 10 Nm of torque is applied to the second limb 44, the joint coupling 102 maintains a ‘rigid’ state 172 in which no rotation occurs because the predefined restoring force is not exceeded and the first or second resiliently compressible member causes the first and second formations 110, 112 to stay in alignment with one another.
  • the rigid state 172 is useful because it prevents the movable joint 40 and, more broadly, the articulated manipulator 50 from moving away from its intended position at the slightest touch while the movable joint 40 is locked.
  • the joint coupling 102 enters a ‘flexing’ state 174.
  • the flexing state 174 exists because the predefined restoring force of one of the first and second resiliently compressible members is now being exceeded and so that resiliently compressible member is being compressed by virtue of the first and second formations 10, 12 being move out of alignment with one another.
  • the flexing state 174 usefully allows the movable joint 40 to temporarily comply if a large enough force is being applied to it. This greatly reduces the likelihood of an accidental knock causing a failure of the locked movable joint due to stresses building up at a fragile component, such as the locking latch 47 for example.
  • the ability of the movable joint to flex may protect the expensive motor-driven components from excessive stresses and possible failure.
  • the joint coupling is configured to allow a rotation of up to 20° in the flexing state 174 before the predefined gripping torque is exceeded.
  • the amount of rotation allowed in the flexing state may be defined by the size and resilience to compression of the resiliently compressible biasing members 118, 120.
  • each of the resiliently compressible members 118, 120 are still further compressible with a force greater than the predefined gripping torque.
  • the resiliently compressible members 118, 120 are not at the maximum limit of their range of potential compression when the predefined gripping torque is exceeded. This ensures that Hooke’s law applies throughout the flexing state 174 so that the degree of rotation remains proportional to the torque being applied.
  • the joint coupling 102 In the slipping state 176, the joint coupling 102 essentially slips past the first limb 42 because the first limb 42 is no longer being gripped tightly enough by the gripping surfaces 136, 138 for the joint coupling 102 to hold its position relative to the first limb 42. This allows the second limb 44 to be moved freely relative to the first limb 42.
  • the slipping state 176 prevents large external forces/torques, which might fully compress one of the resiliently compressible members 118, 120, from causing damage to the locked movable joint 40. Such a force/torque might be accidentally applied by a person attempting to move the articulated manipulator without knowing to first disengage the locking latch 47 or forgetting to do so on that occasion. Alternatively, the locking latch may have failed in the locked position and the operator might be unaware of the failure. If the movable joint were part of an active manipulator, the movable joint may essentially be locked when no power is supplied to the manipulator and the ability for the joint to slip would, therefore, also help to protect the movable joint of an active manipulator.
  • any additional rotation of the second limb 44 relative to the first limb which occurs in the slipping state may not be reversed by the joint coupling 102 as there is no component equivalent to the resiliently compressible members 118, 120 which biases the second limb 44 back to its starting position (the origin of the y- axis). Instead, any additional rotation that occurs in the slipping state 176 may be maintained, resulting in a displacement 178 of the second limb 44 relative to the first limb 42.
  • the master controller 60 may require recalibration with the surgical robot it is configured to control.
  • a joint coupling 202 is shown which is similar to the joint coupling 102 of Figures 6 to 10, in that the second body 206 is rotatably movable relative to the first body 204.
  • each resiliently compressible member 218, 220 comprises an elastomeric block, made of a rubber material for example, rather than a spring.
  • the joint coupling 202 comprises two lots of each of these features, it functions in much the same way as the joint coupling 102 of Figures 6 to 10, whereby each pair of the first and second formations is biased towards alignment so that the first and second bodies 204, 206 are forced towards the balanced configuration shown in Figures 14 and 15.
  • each of the first and second resiliently compressible members 218, 220 has a predefined restoring force.
  • the two first resiliently compressible members 218 work together, as do the two second resiliently compressible members 220. Therefore, in order to move the second body 206 relative to the first body 204, a torque must be applied which is great enough to apply a force that exceeds the predefined restoring force of both first resiliently compressible members 218 or of both second resiliently compressible members 220.
  • the applied force must be about twice as large to further compress the resiliently compressible members 218, 220 when compared to the force that would be required if there was only one pair of first 218 and second 220 compressible members which have the same predefined restoring force.
  • Figures 16 and 17 show the joint coupling 202 if such a torque were being applied to the second body 206 in a clockwise sense (as viewed on the page). As can be seen, both of the second resiliently compressible members 220 are being further compressed in order to rotate the second body 206 relative to the first body 204.
  • joint couplings 2 and 202 shown in Figures 1 to 4 and 14 to 17 respectively should be regarded as having been disclosed in combination with a third body which functions equivalently to the third body 108 shown in Figure 10, that is, combining with the respective first body to grip a limb of a movable joint.

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  • Engineering & Computer Science (AREA)
  • Robotics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Surgery (AREA)
  • Heart & Thoracic Surgery (AREA)
  • Biomedical Technology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Medical Informatics (AREA)
  • Molecular Biology (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Manipulator (AREA)
  • Quick-Acting Or Multi-Walled Pipe Joints (AREA)

Abstract

L'invention concerne un accouplement de joint (2) pour un joint mobile, l'accouplement de joint (2) comprenant : un premier corps (4) comprenant une première formation (10) ; un second corps (6) mobile par rapport au premier corps (4), le second corps (6) comprenant une seconde formation (12) pouvant venir en prise de manière coulissante avec la première formation (10) ; une cavité (14) formée par un ou plusieurs des premier et second corps (4, 6), la cavité (14) ayant une longueur le long de laquelle au moins l'une des première et seconde formations (10, 12) peut se déplacer sur un mouvement du second corps (6) par rapport au premier corps (4) ; et des premier (18) et second (20) éléments élastiquement compressibles reçus à l'intérieur de la cavité (14) dans une configuration partiellement comprimée, les premier et second éléments élastiquement compressibles (18, 20) étant séparés l'un de l'autre par les première et seconde formations (10, 12), sollicitant ainsi les premier et second corps (4, 6) vers une configuration équilibrée dans laquelle les première et seconde formations (10, 12) sont alignées l'une avec l'autre.
PCT/GB2023/050867 2022-04-05 2023-03-31 Accouplement de joint WO2023194707A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB2204988.6A GB2617354B (en) 2022-04-05 2022-04-05 A joint coupling
GB2204988.6 2022-04-05

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WO2023194707A1 true WO2023194707A1 (fr) 2023-10-12

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01193189A (ja) * 1988-01-26 1989-08-03 Toshiba Mach Co Ltd ロボットハンドの追従機構
CN112338957A (zh) * 2020-10-30 2021-02-09 山东大学 基于串联弹性驱动器的腿部关节、腿结构及水下机器人
FR3101802A1 (fr) * 2019-10-15 2021-04-16 Psa Automobiles Sa Dispositif d’interface pour coupler un bras de robot à un outil opérant sur un élément mobile
DE102020102121A1 (de) * 2020-01-29 2021-07-29 Linde Material Handling Gmbh Mobiler Kommissionierroboter und Verfahren zu seinem Betrieb

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102013204588A1 (de) * 2013-03-15 2014-09-18 Siemens Aktiengesellschaft Drehmomentübertragungsvorrichtung, Aktor, Roboter
CN112405594B (zh) * 2020-11-10 2022-02-01 珠海格力电器股份有限公司 机器人关节减振装置及机器人

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH01193189A (ja) * 1988-01-26 1989-08-03 Toshiba Mach Co Ltd ロボットハンドの追従機構
FR3101802A1 (fr) * 2019-10-15 2021-04-16 Psa Automobiles Sa Dispositif d’interface pour coupler un bras de robot à un outil opérant sur un élément mobile
DE102020102121A1 (de) * 2020-01-29 2021-07-29 Linde Material Handling Gmbh Mobiler Kommissionierroboter und Verfahren zu seinem Betrieb
CN112338957A (zh) * 2020-10-30 2021-02-09 山东大学 基于串联弹性驱动器的腿部关节、腿结构及水下机器人

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GB202204988D0 (en) 2022-05-18
GB2617354A (en) 2023-10-11

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