Robot arm, ultrasound robot, and method for controlling a robot arm

Abstract

A robot arm (10) with a robot structure (12), wherein the robot structure (12) has an arm member chain (18), having at least one arm member (14) and at least one joint (16), and a tool (20) connected to the arm member chain (18) for connection to at least one end effector (32), with at least one end effector sensor (22) for detecting forces and / or torques which act on an end effector (32) connected to the tool (20); and with at least one structure sensor (24) for detecting forces and / or torques which act on the robot structure (12). Furthermore, an ultrasound robot (100) and a method for controlling a robot arm (10).

Description

[0001] Robot arm, ultrasonic robot and method for controlling a robot arm

[0002] The invention relates to a robot arm, an ultrasonic robot and a method for controlling a robot arm.

[0003] Robot arms are often used in industrial applications, such as automotive manufacturing, or in medical applications, such as robot-assisted surgery.

[0004] The target trajectories of a lightweight robot, e.g. a robot arm, can basically be generated in three ways:

[0005] - Autonomy: The system independently calculates the desired trajectories and monitors compliance. This requires precise knowledge of the robot's environment, particularly either because it is highly structured and static, or because the robot can acquire all relevant information using appropriate sensors. Furthermore, the ability to respond appropriately to unforeseen disturbances is generally assumed.

[0006] - Teleoperation: The human user is located far away from the robot arm and commands its movements via a suitable input device.

[0007] - Hands-on control / physical human-robot interaction: The human user interacts directly with the robot arm to influence its movements and behavior.

[0008] In the medical field, with its unstructured environment and the often direct contact between robot system and patient, physical human-robot interaction offers advantages in numerous applications. Compared to autonomous systems, the following advantages arise: Since the sensory abilities and expertise of the human user are incorporated into the robot control, the number of sensors in the robot system can be significantly reduced. Since the human user can intervene at any time in the event of malfunctions or unforeseen situations, the system's control software can be significantly simplified.

[0009] In contrast to systems with teleoperation, the following advantages arise: The human user can interact with the patient and the robotic system simultaneously. This provides the best possible information about the surgical process at all times, as well as full control over the subsequent procedure, especially up to the point of foregoing robotic assistance and continuing the procedure manually.

[0010] State-of-the-art robot arms are presented below.

[0011] DE 32 40 251 describes the control of a robot arm using an input device with an integrated force sensor. The input device records the forces and moments exerted by the user. These are transformed into an inertial system, and the desired translation and rotation speeds of the robot end effector are then calculated in the inertial system.

[0012] DE 10 2018 114 644 B3 describes a robot manipulator that has a sensor between the distal robot link and the end effector for detecting a force winder, as well as another sensor on the control housing for detecting a user force or a user moment. Based on the data from these two sensors, a computing unit uses a dynamic model of the robot to calculate a target force or a target moment for displacing the robot links, as well as a target force or a target moment for exerting on an external object by the end effector. DE 10 2013 019 869 A1 describes modular, manually operable input modules that can be mounted either between the mutually movable arm modules or on the tool interface of a robot arm. The user inputs on these modules can be used to control the axes of the robot arm located between the input module and the robot base and, for example, to teach a trajectory.

[0013] DE 10 2015 117 213 B4 describes an advantageous embodiment of the last two axes of a robot arm. The housing connected to the penultimate axis is cylindrically shaped around the last axis. This housing can optionally be equipped with a graphic output unit. Above this housing, one or more input elements are located, which can be rotated, in particular continuously with a detent or detachable clip connection, around the last axis. Below this, the tool interface is connected to the last axis and has a rigid extension for manual movement as well as at least one input element. The states of the input elements and the mechanical state of the robot arm, in particular positions and their derivatives, forces and moments, are used to generate the robot's control instructions.

[0014] DE 10 2016 222 675 A1 describes a robot handheld device that can be coupled to a robot arm via a coupling device between the end effector and the robot arm. The robot handheld device has a handle, several buttons, and a force sensor, at the distal end of which is the interface of the coupling device. Using this interface, the robot handheld device can be detachably connected to the coupling device on a robot arm. From this point on, the forces and moments exerted by the user on the handle can be measured and used to manually guide the robot. EP 2 194 434 B1 describes the control of an industrial robot using a portable programming device and a manual guidance device that is coupled to the movable robot structure or the end effector via quick-coupling devices.The manual guidance device can communicate wirelessly with its associated programming device. The programming device, in turn, is connected to the robot arm's control unit via cable or wirelessly. It is possible to configure the programming device or the control unit to selectively limit the robot's movements for one or more degrees of freedom.

[0015] Takacs2020 (Takacs, Bence, and Tamas Haidegger. "Autonomous applied robotics: Ultrasound-based robot-assisted needle insertion system concept and development." 2020 IEEE 15th International Conference of Systems Engineering (SoSE). IEEE, 2020.) describes a system for venous injection consisting of an LBR iiwa robot (KUKA, Augsburg, Germany), an ultrasound transducer, and a tool with three degrees of freedom for positioning and inserting the injection needle. The interaction forces between the tool and the patient can be measured using a force sensor between the tool and the robot's tool interface.

[0016] In the Innomedicus Artemis System (https: / / www.innomedicus.com / de / urology / artemis / ) for prostate biopsy, an ultrasound transducer is attached to a robotic arm, and the ultrasound image is registered against preoperative image data. A guide for the biopsy needle is located parallel to the longitudinal axis of the ultrasound transducer, allowing it to be precisely aligned to pre-planned points in the prostate.

[0017] Lim2019 (Lim, Sunghwan, et al. "Robotic transrectal ultrasound guided prostate biopsy." IEEE Transactions on Biomedical Engineering 66.9 (2019): 2527- 2537.) describes another robotic system for prostate biopsy, which has similar features and a similar workflow as the Innomedicus Artemis system.

[0018] Compared to the Innomedicus Artemis system, the iSR'obot™ Mona Lisa system (https: / / biobotsurgical.com / ) for prostate biopsy also offers the option of actuated adjustment of the position and orientation of the biopsy needle relative to the ultrasound transducer. The translational movement of the biopsy needle is also actuated.

[0019] Welleweerd2020 (Welleweerd, Marcel K., et al. "Design of an end-effector for robot-assisted ultrasound-guided breast biopsies." International Journal of Computer Assisted Radiology and Surgery 15.4 (2020): 681-690.) describes a system for ultrasound-guided breast biopsies. This system is designed as an end-effector for a lightweight robot that incorporates an ultrasound transducer, a stereo camera, and a needle guide actuated by three servomotors.

[0020] JP 5637883 B2 describes a control device for a robot with a sensor on an operating handle.

[0021] A disadvantage of state-of-the-art systems and methods is that the control of robot arms, particularly as shown here, is inaccurate.

[0022] The object of the invention is to provide a robot arm, an ultrasonic robot and a method for controlling a robot arm, wherein the control of the robot arm is optimized, in particular more precise.

[0023] The objects are achieved according to the invention by a robot arm according to claim 1, an ultrasound robot according to claim 12, and a method for controlling a robot arm according to claim 13. The robot arm according to the invention is, in particular, a medical robot arm. Particularly preferably, it is a hands-on robot arm. A hands-on robot arm within the scope of the present invention is, in particular, a robot arm designed for direct interaction of a user with the robot arm, in particular with one or more robot links, in order to influence the movements and / or behavior of the robot arm. The robot arm has a robot structure with an arm link chain and a tool. The arm link chain has at least one arm link and at least one joint. The at least one joint is, in particular, a joint with one, two, or three degrees of freedom.The at least one joint is preferably a cardan joint or a ball joint. At least one tool is connected to the arm link chain, in particular distally. The tool is designed for connection, in particular detachable or non-detachable, to at least one end effector. The robot arm further comprises at least one end effector sensor for detecting forces and / or moments acting on an end effector connected to the tool. Preferably, one end effector sensor is provided for each end effector to be connected or connected. The end effector sensor is in particular arranged and / or designed such that forces and / or moments acting on the end effector from the environment, in particular from a patient or a workpiece, are detected. The robot arm further comprises at least one structure sensor for detecting forces and / or moments acting on the robot structure.The structure sensor is in particular arranged and / or designed such that forces and / or moments acting on the robot structure by a user are detected. The user is in particular medical personnel. Preferably, the arm link chain is connected proximally to a fastening device, e.g. a stand. Preferably, the robot arm, in particular the tool, has an input interface for inputs from a user. The input interface has, for example, at least one button, a thumbstick, a directional pad and / or a touchscreen. Preferably, the robot arm, in particular the tool, has an output interface for optical and / or acoustic outputs to a user. The output interface has, for example, at least one LED, a display and / or a loudspeaker.

[0024] The invention makes it particularly advantageous to detect and quantify the physical contact of a user with the robot arm, in particular the arm structure. The present invention advantageously enables the detection of forces and / or moments acting on end effectors, in particular from the environment, such as a patient, and on the robot structure, in particular from a user. Preferably, a distinction can be made between forces on the end effector, in particular on the patient side, and forces on the tool and / or robot, in particular on the operator side, preferably through separate measurements. This represents a significant advantage over existing systems in which pure position control of the robot system takes place. This pure position control was found to be insufficient within the scope of the invention.In contrast to the prior art, the invention is particularly advantageous in permanently monitoring the interaction forces between the robot system and the patient, for example in order to be able to detect deviations from the desired process at an early stage and / or to be able to correctly use medical end effectors attached to the robot, e.g. ultrasound transducers, biopsy forceps, injection needles.

[0025] The invention thus provides particular advantages over most of the prior art systems, e.g., DE 10 2013 019 869 A1, DE 10 2015 117 213 B4, EP 2 194 434 B1, JP 5637883 B2, in which no differentiation is possible between the interaction forces between user and robot system, or between robot system and patient or workpiece. In DE 32 40 251, particularly in contrast to the invention, no dynamic decoupling of the components of the workspace is possible. Since the robot structure in DE 32 40 251 itself does not have any sensors, in particular force-torque sensors, user interactions cannot be recorded. Compared to DE 10 2018 114 644 B3, for example, there is the advantage that a specific design of the robot, especially between the last axis and the tool interface, is not required and thus implementation with common robots, especially lightweight robots, is possible.In contrast to the present invention, the Takacs2020 telemanipulation system does not allow direct user interaction and thus does not allow separate recording of interaction forces with the environment and user interaction forces. In contrast to the Innomedicus Artemis System, Lim2019, and iSR'obot™ Mona Lisa System, the present invention particularly advantageously enables recording of the interaction of the end effector with the environment and the arm structure with a user. This also applies in particular to the Welleweerd2020 system, which is designed for autonomous operation.

[0026] Further advantages of the invention over the prior art, which is specifically mentioned, are that the system of the present invention can be used with common robot arms, in particular lightweight robot arms, and / or that the system can be used for actuated end effectors.

[0027] In a preferred embodiment, the at least one end effector sensor is a force sensor, a torque sensor, or a force-torque sensor. The force-torque sensor is, in particular, a force-torque sensor with a degree of freedom of 2 to 6. On the other hand, it is also possible for the end effector sensor to be a force sensor with one degree of freedom, preferably in the longitudinal direction of the end effector. In a preferred embodiment, the at least one structural sensor is a force sensor, a torque sensor, or a force-torque sensor. The force-torque sensor is, in particular, a force-torque sensor with a degree of freedom of 2 to 6. A force-torque sensor with 6 degrees of freedom, also called a 6-DOF force-torque sensor, is particularly preferred.

[0028] In a preferred embodiment, the arm-link chain has a plurality of arm links and / or a plurality of joints. In particular, two adjacent arm links are movably connected to one another by a respective joint. The arm-link chain preferably has a plurality of arm links with joints arranged between them.

[0029] In a preferred embodiment, a structural sensor is located between the tool and the arm link chain for detecting forces and / or moments acting on the tool. This structural sensor is preferably a 6-DOF force-moment sensor. This structural sensor can, in particular, be the only structural sensor of the robot arm according to the invention; alternatively, at least one additional structural sensor can preferably be provided for detecting forces and / or moments acting on the robot structure.

[0030] In a preferred embodiment, a structural sensor is provided for at least one arm link to detect forces and / or moments acting on this arm link. Preferably, a structural sensor is provided for several arm links, particularly preferably for each arm link, to detect forces and / or moments acting on the respective arm link. In particular, this at least one structural sensor is connected to the respective arm link, preferably directly. This at least one structural sensor is preferably a 3-DOF force-moment sensor.

[0031] In a preferred embodiment, the robot arm has at least one end effector that is detachably or non-detachably connected to the tool. The at least one end effector is, in particular, an ultrasound transducer, a biopsy forceps, or an injection needle. In particular, several end effectors, preferably several of the above-mentioned end effectors, are connected to the tool. The several end effectors are, in particular, arranged in parallel. The at least one end effector is, in particular, movable or immovable; and / or actuated or non-actuated.

[0032] In a preferred embodiment, an end effector sensor for detecting forces and / or moments acting on the tool is arranged between the at least one end effector, in particular between each end effector, and the tool. This at least one end effector sensor is preferably connected, preferably directly, to the respective end effector and the tool.

[0033] In a preferred embodiment, the robot structure has a tool interface arranged between the arm link chain and the tool for connecting, in particular detachably, the tool to the tool interface. The tool interface has, in particular, a tool center point (TCP). The tool center point is not a real part, but rather a point defined relative to the last robot link. This point can, for example, also be located outside the tool. This point is used, in particular, to describe the movements of the tool in Cartesian space.

[0034] In a preferred embodiment, a structural sensor for detecting forces and / or moments acting on the tool interface, and thus in particular also on the tool, is arranged between the arm link chain and the tool interface. This structural sensor is preferably a 6-DOF force-moment sensor. This structural sensor can in particular be the only structural sensor of the robot arm according to the invention; alternatively, at least one further structural sensor can preferably be provided for detecting forces and / or moments acting on the robot structure. In a preferred embodiment, the robot arm further comprises a control unit for controlling the robot arm. The control unit comprises in particular a processor and / or a controller.The control unit is preferably configured to receive and, in particular, process the forces and / or moments detected by the end-effector sensor and the structural sensor. The control unit is preferably configured to move the robot structure and / or to actuate the at least one end-effector based on the forces and / or moments received and, in particular, processed by the end-effector sensor and the structural sensor.

[0035] In a preferred embodiment, the robot structure has at least one virtual fixture, in particular for limiting and / or damping the movement of the robot arm. The control unit is preferably configured to adjust the at least one virtual fixture based on the forces and / or moments received and in particular processed by the end effector sensor and the structure sensor. The virtual fixture is in particular not a real part. It is defined and parameterized in particular in software of the robot arm, preferably the control unit, in order to influence the behavior of the real robot arm, for example by preventing movements in certain areas.

[0036] The ultrasound robot according to the invention is, in particular, an ultrasound robot for facet joint injection. The ultrasound robot has a robot arm with one or more features of the robot arm according to the invention. Furthermore, the ultrasound robot has an ultrasound transducer connected to the tool as an end effector. It is preferred that the ultrasound robot further comprises an injection needle connected to the tool as a further end effector. The ultrasound transducer and injection needle are arranged in particular in parallel. The injection needle is preferably arranged in the image plane of the ultrasound transducer, but can in particular be moved and tilted therein.

[0037] One example in which the invention can be used particularly advantageously is robot-assisted treatment of facet joint inflammation using ultrasound imaging. In this procedure, pain-relieving and anti-inflammatory medications are injected into the facet joints of the human spine, with a live ultrasound image being used for correct needle positioning. Until now, such procedures have generally been performed manually, placing considerable coordination and cognitive demands on the physician performing the procedure. The physician must simultaneously guide the ultrasound transducer, interpret the ultrasound image, and coordinate the injection needle.Attaching the ultrasound transducer and needle guide to a robot arm enables reproducible, gravity-compensated movement of the ultrasound transducer (and, if desired, limitation of the range of motion) and simultaneously ensures the correct positioning of the needle guide relative to the ultrasound transducer. It has been determined that the quality of the ultrasound image depends heavily on the adequate orientation of the transducer and the contact pressure. Therefore, in robot-assisted scenarios, it is advantageous for the robot system to be able to measure the interaction forces between the ultrasound transducer and the patient. If the physician controls the system during the procedure using physical human-robot interaction, it is advantageous to ensure that the forces and moments exerted by the physician do not impair the measurement of the interaction forces.

[0038] The method according to the invention for controlling a robot arm is, in particular, a method for controlling a medical robot arm. It is preferably a method for controlling a robot arm with one or more features of the robot arm according to the invention or of the ultrasound robot according to the invention. The method relates, in particular, to the movement of the robot arm, preferably of the robot structure. The method preferably relates exclusively to the movement of the robot arm, preferably of the robot structure. In particular, the method does not relate to the control, preferably movement and / or actuation, of end effectors. However, the method preferably relates, for example, to the detection of forces during end effector actuation, for example during needle advancement. Thus, the method can preferably detect a collision, for example with a bone, and react accordingly.For example, in particular the feed can be reduced or stopped, or a return feed can take place, preferably by a predefined distance. The method comprises the step of detecting forces and / or moments acting on at least one end effector of the robot arm. The step of detecting forces and / or moments acting on at least one end effector of the robot arm is preferably carried out by means of at least one end effector sensor, preferably connected to at least one end effector. The method further comprises the step of detecting forces and / or moments acting on a robot structure of the robot arm. The step of detecting forces and / or moments acting on the robot structure of the robot arm is preferably carried out by means of at least one structure sensor, preferably connected to the robot structure.These two detection steps preferably occur at least partially simultaneously or sequentially. The method preferably further comprises the step of determining, in particular calculating, interaction forces and / or interaction moments of the robot arm based on the detected forces and / or moments. The determination of the interaction forces and / or interaction moments takes place in particular by means of a control unit of the robot arm.

[0039] In a preferred embodiment, the method comprises the further step of outputting the interaction forces and / or interaction moments, in particular to an overall control system of the robot arm. The "output" of the interaction forces and / or interaction moments involves, in particular, a transmission of the interaction forces and / or interaction moments and / or a visual display of the interaction forces and / or interaction moments.

[0040] The method further comprises, in particular, storing the interaction forces and / or interaction moments, e.g., for documentation purposes. Furthermore, the method can comprise further use of the recorded forces and / or moments in the system control. For example, the robot movement, e.g., the TCP of the robot, can be controlled in certain Cartesian spatial directions based on the end-effector forces and / or moments and / or in other Cartesian spatial directions based on the interaction forces and / or moments between user and tool or user and robot arm. In particular, it is also possible to use both pieces of information, whereby they are preferably weighted against each other either by fixed weighting factors or adjustable weighting functions. It is also possible, in particular, for signals to be processed before being passed on to the control system, e.g.,by signal filtering or adapting the signal frequency to the control frequency via downsampling and / or interpolation.

[0041] The invention is explained in more detail below using preferred embodiments with reference to the accompanying drawings.

[0042] They show:

[0043] Fig. 1 is a schematic representation of an embodiment of an ultrasound robot according to the invention with an embodiment of a robot arm according to the invention,

[0044] Fig. 2 is a schematic representation of a further embodiment of an ultrasonic robot according to the invention with a further embodiment of a robot arm according to the invention, Fig. 3 is a diagrammatic representation of an embodiment of a method according to the invention for controlling a robot arm,

[0045] Fig. 4 is a schematic representation of a robotic system for

[0046] Visualization of an embodiment of a robot arm according to the invention and for visualizing a method according to the invention for controlling a robot arm,

[0047] Figs. 5a-5b Network representations of teleoperation models for implementing an embodiment of an ultrasound robot according to the invention, an embodiment of a robot arm according to the invention and / or a method according to the invention for controlling a robot arm,

[0048] Fig. 6 a diagrammatic representation of a strategy for generating the

[0049] Controller inputs for implementing an embodiment of an ultrasonic robot according to the invention, an embodiment of a robot arm according to the invention and / or a method according to the invention for controlling a robot arm,

[0050] Fig. 7 is a schematic perspective view of a tool with

[0051] End effectors for implementation within the framework of a further embodiment of an ultrasound robot according to the invention and / or a further embodiment of a robot arm according to the invention,

[0052] Figs. 8a-8b show representations of a tool with an end effector for implementation within the scope of a further embodiment of an ultrasonic robot according to the invention and / or a further embodiment of a robot arm according to the invention, Fig. 9 shows a representation of a kinematics for implementation of an embodiment of an ultrasonic robot according to the invention, an embodiment of a robot arm according to the invention and / or a method according to the invention for controlling a robot arm,

[0053] Fig. 10 shows a representation of a further tool variant for implementation within the framework of a further embodiment of an ultrasonic robot according to the invention and / or a further embodiment of a robot arm according to the invention,

[0054] Figs. lla-llb show representations of a further tool variant for implementation within the framework of a further embodiment of an ultrasonic robot according to the invention and / or a further embodiment of a robot arm according to the invention, and

[0055] Figs. 12a-12b show representations of a further tool variant with an end effector within the framework of a further embodiment of an ultrasonic robot according to the invention and / or a further embodiment of a robot arm according to the invention.

[0056] Similar or identical components or elements are identified in the figures with the same reference numerals or variations thereof (e.g., 24 and 24i, 24i+i). Particularly for improved clarity, elements that have preferably already been identified are not provided with reference numerals in all figures. The described device features can be implemented, in particular, within the scope of the ultrasound robot 100 according to the invention and / or within the scope of the robot arm 10 according to the invention. The described method features, in turn, can be used, in particular, when carrying out the method according to the invention.Furthermore, the described method features can be implemented in particular within the scope of the ultrasonic robot 100 according to the invention and / or within the scope of the robot arm 10 according to the invention, wherein preferably the ultrasonic robot 100 and / or the robot arm 10, particularly preferably a control unit 23 of the ultrasonic robot 100 and / or the robot arm 10, is configured to execute at least one of the method features.

[0057] The concepts of the invention, in particular the embodiments, are applicable in the field of hardware as well as in medical applications, particularly in medical applications in which a rotationally symmetrical tool is to be positioned with robot support using intraoperative imaging, e.g., placing bone screws, taking biopsies. Likewise, the methods, in particular control concepts, are preferably transferable to other applications, for example, in which the interaction forces between the user and the robot arm, as well as between the robot arm and the environment, are to be measured synchronously.

[0058] Figure 1 shows an embodiment of an ultrasound robot 100 according to the invention, in particular for facet joint injection, with an embodiment of a robot arm 10 according to the invention.

[0059] The robot arm 10 has a robot structure 12 with an arm link chain 18 and a tool 20 connected distally to the arm link chain 18 via a tool interface 26.

[0060] The arm link chain 18 has two arm links 14i, 14i+i movably connected via a joint 16i+i. The arm link 14 is movably connected to a base 28 via a joint 16i. A tool interface 26 is connected distally to the arm link 14i+i. A tool 20 is connected, in particular detachably, to the tool interface 26. The tool interface 26 has a structural sensor 24. The structural sensor 24 is arranged in particular between the tool interface 26 and the tool 20 and / or between the tool interface 26 and the arm link chain 18. The structural sensor 24 is designed and / or arranged to detect forces and / or moments exerted by a user 102 on the tool 20. In particular, the structural sensor 24 is a 6-DOF force-torque sensor. The user 102 is, in particular, a medical professional who, for example, moves the tool 20 with the hand 106 and thus applies forces and / or torques to the tool 20.

[0061] Two end effectors 32a, 32b are connected, in particular detachably, to the tool 20. End effector 32a is an ultrasound transducer 32a, and end effector 32b is an injection needle 32b. The injection needle 32b is connected to the tool 20 via a needle guide 34b, which is in particular actuatable and / or movable.

[0062] Two end effector sensors 22a, 22b are provided to detect forces and / or moments acting on the end effectors 32a, 32b from the environment, in particular from patient 104, for example during an ultrasound-assisted facet joint injection. End effector sensor 22a is designed and / or arranged to detect forces and / or moments acting on the ultrasound transducer 32a. In particular, end effector sensor 22a is arranged between the ultrasound transducer 32a and the tool 20. End effector sensor 22b is designed and / or arranged to detect forces and / or moments acting on the injection needle 32b. In particular, the end effector sensor 22b is arranged between the injection needle 32b and the tool 20, preferably between the needle guide 34b and the tool 20.The end-effector sensor 22a and / or end-effector sensor 22b is, in particular, a force sensor, a torque sensor, or a force-torque sensor with two to six degrees of freedom, particularly preferably a 6-DOF force-torque sensor. Alternatively, the end-effector sensor 22a and / or end-effector sensor 22b can also be a 1-DOF force sensor. The end-effector sensor 22b is preferably a 1-DOF force sensor, which particularly detects the force in the longitudinal direction of the injection needle 32b.

[0063] The detected forces and / or moments acting on the tool 20 of user 102 and on the end effectors 32a, 32b of patient 104 are detected via the sensors 24, 22a, 22b and can be used to control the robot arm 10. In particular, the detected forces and / or moments are transmitted to a control unit 23 for the robot arm 10. From the detected forces and / or moments, interaction forces and / or interaction moments of the robot arm 10 can be calculated, preferably by the control unit 23, and these can preferably be incorporated into the overall control, in particular the overall control, of the robot arm 10.

[0064] Figure 2 shows a further embodiment of an ultrasound robot 100 according to the invention, in particular for facet joint injection, with a further embodiment of a robot arm 10 according to the invention.

[0065] In the embodiment of Figure 2, a structure sensor 24i, 24i+i is provided for each arm member 14i, 14i+i, in particular connected to the respective arm member 14i, 14i+i.

[0066] Furthermore, in particular a structural sensor 24i+2 is provided for detecting forces and / or moments on the tool 20, in particular connected to the tool interface 26.

[0067] The plurality of structural sensors 24i, 24i+i, 24i+z particularly advantageously enable the detection of forces, preferably exerted by a user 102, on the respective elements of the robot structure 12. Three end effectors 32a, 32b, 32c are shown connected, in particular detachably, to the tool 20. End effector 32a is shown as an ultrasound transducer 32a, which is connected to the tool 20 by means of two fastening elements 34a1, 34a2 movably connected via joint 30. Furthermore, an injection needle 32b is connected to the tool 20 via needle guide 34b, and biopsy forceps 32c are connected to the tool 20 via fastening element 34c as end effectors 32b, 32c. For each end effector 32a, 32b, 32c, an end effector sensor 22a, 22b, 22c is provided for detecting forces and / or moments on the respective end effector 32a, 32b, 32c, in particular arranged between the end effector 32a, 32b, 32c and the tool.

[0068] Preferably, the following method steps can be implemented and / or the robot arm 10 can be designed with the following method steps: The interaction forces of a user 102 and the robot structure 12 of the robot arm 10 between two sensors 24i, 24i+i can be calculated by subtracting the measured values ​​of two consecutive sensors 24i, 24i+i in the robot structure 12, taking into account the dynamic model of the robot arm 10. The interaction forces of user 102 and tool 20 can be calculated, taking into account the dynamic model of the tool 20, as the difference between the measured values ​​of the sensor of the tool interface 26 and the sum of the measured values ​​of the sensors 22a, 22b, 22c at the end effectors 32a, 32b, 32c; Alternatively, an external force sensor could also be used between tool interface 26 and tool 20.The interaction forces between end effectors 32a, 32b, 32c and the environment can be detected, in particular read, directly using the respective end effector sensors 22a, 22b, 22c. The force sensor 26 can in particular be integrated into the robot arm 10, preferably arranged between the arm link chain 18 and the tool interface 26, for example, approximately as shown in Fig. 2. With this arrangement, it is preferred that the weight and, in the case of dynamic movements, the mass inertia of the tool interface 26 are determined and, in particular, incorporated into the calculations of the tool interaction forces. Alternatively, the force sensor can in particular be arranged between the tool interface 26 and the tool 20.

[0069] A preferred embodiment of the method according to the invention for controlling a robot arm is described below with reference to Figure 2. However, the features described in the context of the following method can preferably also be implemented independently of the embodiment of Figure 2 within the framework of a method according to the invention for controlling a robot arm and / or within the framework of a control unit 23 of a robot arm 10 according to the invention and / or within the framework of a control unit 23 of an ultrasound robot 100 according to the invention. If the steps are implemented within the framework of a control unit 23, it is preferred that the control unit 23 is set up to carry out corresponding method steps, for example by means of a processor and / or FPGAs.

[0070] A first step consists in detecting forces and / or moments acting on the end effectors 32a, 32b, 32c of the robot arm 10, in particular by means of the corresponding end effector sensors 22a, 22b, 22c.

[0071] A second step consists in detecting forces and / or moments acting on the robot structure 12, in particular on the arm links 14i, 14i+i and / or the tool 20 of the robot arm 10, in particular by means of the corresponding structure sensors 24i, 24i+i, 24i+2.

[0072] In particular, the first and second steps may be carried out in the following order: first step 1, then step 2; or first step 2, then step 1; or step 1 and step 2 in parallel; or step 1 and step 2 overlapping.

[0073] A further step consists in determining, preferably calculating, interaction forces and / or interaction moments of the robot arm based on the detected forces and / or moments, in particular by the structural sensors 24i, 24i+i, 24i+2 and / or the end effector sensors 22a, 22b, 22c. The determination of the interaction forces and / or interaction moments takes place in particular by means of a control unit 23 (cf. Fig. 1) of the robot arm 10. Preferably, 6x1 force-moment vectors are calculated from the detected sensor data, whereby in particular forces and moments due to gravity and system dynamics are disregarded.

[0074] A preferred calculation procedure of the method and / or the control unit of the robot arm 10 is:

[0075] Fuser_ArmStructure_I — Fsensor_ArmStructure_I" Fsensor_ArmStructure_I+l" FDyn_ArmStructure_I

[0076] With Füyn Armstructure i : Weight force and forces resulting from movement of the arm limb i

[0077] Fuser Tool = Fsensor TCP-S" F'sensor.EndEffectorl- FDyn_ToolStructure

[0078] With Füyn Toolstructure : Weight force and forces resulting from movement of the tool

[0079] Where n: number of end effectors

[0080] FEndEffectorl — Fsensor_EndEffectorI FEndEffectorll — Fsensor_EndEffectorII FEndEffectorl II — Fsensor_EndEffectorIII where Fuser Armstructurei i is the external force-moment vector on the robot structure 12 between joint 16i and joint 16i+i, in particular between the two structure sensors 24i, 24i+i, Fsensor_Armstructurei is the force-moment vector measured at the joint 16i, in particular at the structure sensor 24i, Fuser _TOOI is the external force-moment vector on the tool 20, Fsensor TCP is the force-moment vector measured at the structure sensor 24I+2, at the tool interface 26 (TCP) of the robot arm, Fsensor _End Effecton is the force-moment vector measured at the end effector 32a, 32b, 32c with the respective End effector sensor 22a, 22b, 22c measured force-moment vector and FEndEffectorl is the external force-moment vector on the respective end effector 32a, 32b, 32c (see Fig. 2).The reference system can be fixed to the end effector or be a fixed (inertial) world coordinate system. However, it is preferred that all force-moment vectors be in the same reference system or be converted to it. The torques for the individual joints 16i, 16i+i, 16i+z can be calculated, in particular, from the Cartesian force-moment vectors by multiplying them by the corresponding Jacobian matrices, preferably fixed to the body or inertially. The variables F are, in particular, six-dimensional vectors with three forces and three moments.

[0081] Information regarding the preferred calculation procedure can be found in: Iskandar, Maged and Eiberger, Oliver and Albu-Schäffer, Alin and De Luca, Alessandro and Dietrich, Alexander (2021) Collision Detection, Identification, and Localization on the DLR. SARA Robot with Sensing Redundancy; In: 2021 IEEE International Conference on Robotics and Automation, ICRA 2021. In particular, within the scope of the present invention, it is preferred to implement the calculation procedure from this source, whereby within the scope of the invention, the method described there is particularly preferably implemented, showing how the second derivative of the measured joint position - i.e. the calculation of the acceleration - can be avoided in order to improve the signal-to-noise ratio.

[0082] The calculated 6x1 force-moment vectors can be used in particular to control the robot arm 10, preferably different joints 16i, 16i+i, 16i+2 of the robot arm 10. For example, the Füser_Arm-Structurall can be used to control the zero-space movement, and the Fuser_TOOI can be used to move the tool 20 at the tool interface 26 of the robot arm 10, whereby optionally virtual fixtures 318 based on FEndEffecton (see Fig. 5b) can limit the interaction forces with the environment.

[0083] A preferred control architecture of the method and / or the control unit consists of a control architecture with decoupled degrees of freedom. In particular, a task space controller TSC(x ~d vww as part of the process and / or the control unit in each task space coordinate x = (%, y, z, a, ß, y)T separately. In this way, either a Cartesian impedance controller / , which controls positions and orientations with the desired interaction dynamics (mass-spring-damper), or a force / torque controller F, which controls the forces and moments, is activated independently for all coordinates of the task space. The control processes in different coordinates are, in particular, dynamically decoupled to avoid crosstalk between the control processes in the different coordinates. For this purpose, a separate controller is implemented for each of the six degrees of freedom.

[0084] A preferred strategy for generating controller inputs of the method and / or the control unit 23 is: The desired inputs x ~d = (xd, yd, zd, ad, βd, yd)T for the impedance controller I or ww~d - (ffx,d, ffy,d, ffz,d, rx,d, ry,d, rz,d)T for the force / torque controller F are provided in particular by the high-level software of the robot system. If this only provides discrete setpoints, in particular a Cartesian interpolator is used to provide the desired states at the control rate. If the high-level software cannot provide a suitable input for a coordinate jj, the controller is switched in particular to Fjj-0 to control a zero force or zero torque for this particular coordinate jj. This makes the robot reversible in this coordinate. Since no forces are applied, the control is inherently safe.This allows the user to intervene by manually correcting or completing the respective subtask in HandsOn mode.

[0085] The method is preferably implemented and / or the control unit 23 is configured, in particular by means of high-level software, to identify the current step in the course of the operation based on the system state and the sensor data and to adapt the controller inputs based on this. If the current operation step cannot be determined with sufficient certainty, in particular either a user input can be requested or the strategy described above for generating the controller input without a suitable input comes into effect. In order to be able to make sufficiently precise statements about the reliability of determining the operation step, in addition to the sensor values, the associated error estimates are preferably also reported, preferably to the control unit 23, particularly preferably to the high-level software.

[0086] Furthermore, a combination of inertial scaling, haptic guidance with virtual fixtures, and force feedback is preferably implemented in the control unit 23, for example, in a controller of the control unit 23 or within the scope of the method. This preferably enables not only precise feedback of the measured forces to the user 102, but also modification of the measured values ​​through inertial scaling and virtual fixtures, particularly by means of the proposed controller.

[0087] A preferred strategy for optimizing retractability through inertial scaling of the method and / or the control unit 23 is: To further increase retractability, inertial scaling can preferably be implemented; in particular, the controllers can include inertial scaling. This modifies, in particular, the inertia perceived by the user 102 according to the requirements of the respective application. This can give the user, for example in hands-on mode, the feeling that the robot arm they are moving is, in particular almost, massless and / or frictionless. For this purpose, the weight of the remaining tool can preferably be compensated, so that the user preferably has the feeling of only moving the ultrasonic transducer.

[0088] Virtual fixtures are preferably implemented within the scope of the method and / or by means of the control unit 23: During the manual movement of the robot arm 10, in particular, virtual fixtures AVlrtualFlxture^x ~d, pVF,d) can be activated and parameterized by pVF,d, in particular to represent haptic guidance primitives and exclusion zone restrictions, which can reduce the cognitive load on the user and increase safety. The virtual forces FV resulting from the virtual fixtures can, in particular, be added to the pre-processed force-moment vectors at the end effectors FEndEffectori in order to implement virtual haptic guidance.

[0089] Preferably, disturbance observers and / or safety systems are implemented within the framework of the method and / or by means of the control unit 23: Preferably, at least one disturbance observer PDistObs(ww ^EE) monitors, in particular permanently, all F / T sensor information of the robot arm 10 in order to distinguish between unintentional collisions and intended user or environmental interactions. Safety is guaranteed in particular by limiting forces and speeds and ensuring the stability of the controlled system, for example, by passivity observers.

[0090] A preferred embodiment of the method according to the invention is illustrated in a flowchart in Figure 3. First, forces and / or moments of the robot structure 12 are detected, in particular by means of at least one structure sensor 24 (step 202), and forces and / or moments of the at least one end effector 32 are detected, in particular by means of at least one end effector sensor 22 (step 204).

[0091] Preferably, the detected forces and / or moments are preprocessed, for example, by filtering noise and / or compensating for a static offset (step 206). Subsequently, the preprocessed forces and / or moments, in particular, are used together with the forces and / or moments resulting from a dynamic model of the robot arm 10 (step 208) to calculate the interaction forces and / or moments (step 210). These are then preferably transformed into a common coordinate system (step 212) and preferably output to the control, in particular the closed-loop control, of the overall system of the robot arm 10 (step 214).

[0092] Figure 4 shows a schematic representation of a preferred robotic system 1000 implemented in an ultrasound robot 100 according to the invention and / or a robot arm 10 according to the invention. The forces F and masses M of the robotic system 1000 are shown in one degree of freedom. The system 1000 consists of the robot structure 12, the tool 20, and the end effector 32. The external force Fh acting on the system, for example, by a user 102, and the force Fe, by the environment 105, for example, a patient 106, can be determined using the respective sensors 22, 24, in particular designed as 6-DOF force-torque sensors. F c is the force applied to the robot arm 10 in this degree of freedom by a preferred force controller.

[0093] The two sensors 22, 24 supply as measured values ​​in particular the forces Fi and F2, whereby, preferably if the forces and / or moments resulting from the masses and mass inertias of the end effector and tool are not taken into account, the following applies: F2 = - Fe F1 = Fh - Fe, thus Fe = - F2Fh = Fi - F2.

[0094] The equation of motion of the entire system is therefore:

[0095] M t V = F c + Fh — F e — DK, where:

[0096] Mt = Mr + Mh + M P ,

[0097] V is the speed of the entire system, and

[0098] D is the damping of the robot. The actuating force of a force controller for inertial scaling can be calculated as F c = K*(Fh - Fe).

[0099] This results in the equation of motion of the entire system:

[0100] The last line describes the force Fh felt by the user when moving the tool. In particular, the user should ideally have the feeling of moving the end effector alone when moving the tool attached to the robot and of feeling its interaction forces with the environment Fe:

[0101] By adjusting the scaling factor K of the force controller accordingly, this behavior can almost be achieved:

[0102] The remaining disturbance due to the damping D can be calculated by inserting a damping term into F c be further reduced.

[0103] Figures 5a and 5b show network representations of teleoperation models for implementing an embodiment of an ultrasound robot 100 according to the invention, an embodiment of a robot arm 10 according to the invention and / or a method according to the invention for controlling a robot arm 10.

[0104] The system described above in Figure 4 can be converted, in particular, into the teleoperation model shown in Figure 5a. The real leader comprises the robot structure 12, and the virtual follower comprises the end effector 32, particularly with the desired dynamics. The PCR (Passive Coupling Reference) block 306 ensures that the overall system behaves passively, i.e., does not generate any energy.

[0105] The port network representation uses velocity (V) and force (F) sources. Specifically, if the user 102 moves the robot 12 at a velocity Vd, this will be communicated to the virtual follower, so that the virtual follower, specifically the end effector 32, also moves at the desired velocity Vd. This is done via the "V-Source" block 310. The desired velocity Vd is commanded to the Ctrl block, position controller 312, so that the Ctrl generates the force Fc to move the end effector 32 to follow the velocity Vd by comparing it with the end effector's velocity Vr.

[0106] Specifically for applications with shared control, virtual fixtures 318 are implemented in Fig. 5b to stop the movement of the end effector in specific directions by exerting a force Fv on the end effector. The end effector block 315 receives a weighted sum of the forces from Ctrl 312 and the virtual fixtures 318. That is, Fs=WcFc+WvFv, where the weights Wc and Wv determine the control authority of the forces Fc and Fv, in particular who has more control over the end effector 32. For example, if Wv=0, the end effector 32 is moved entirely by the user. For example, if Wc=0, the virtual fixtures have complete control over the movement of the end effector. The weights Wc and Wv can take values ​​between 0 and 1, depending on which degrees of freedom / directions of movement need to be controlled by the two controllers. These weights are determined by block 313 of the shared control.

[0107] Figure 5b shows an extension of the teleoperation model from Figure 5a by virtual fixtures 318. The forces generated by the virtual fixtures 318, in particular virtual ones, are passed on as additional forces to the virtual follower and forwarded to the user 102 via the force Ff generated by the force controller 308 on the leader side, where: Ff = K*(Fh - Fe - F v ).

[0108] User 102 and robot structure 12 are combined in block 303, end effector 32 and environment are combined in block 315.

[0109] Figure 6 shows a diagrammatic representation of a strategy for generating the controller inputs for implementing an embodiment of an ultrasonic robot 100 according to the invention, an embodiment of a robot arm 10 according to the invention and / or a method according to the invention for controlling a robot arm 10.

[0110] To ensure that the control system always receives valid default values, the setpoints (step 402) for forces and / or moments, e.g. from the control unit 23, in particular from high-level software, of the robot arm 10 are checked again (step 404) before being passed on to the control system, in particular the closed-loop control system, and modified if necessary (step 406). If the high-level software does not supply a valid setpoint for a coordinate j, a zero force is commanded in this coordinate. If the control unit 23, in particular the high-level software, supplies only a discrete value for a coordinate j, ie in particular with an update rate < the control rate of the robotic system, the input value for the controller is calculated for intermediate periods using a Cartesian interpolator and modified accordingly (step 410).Figure 7 shows a schematic, perspective view of a tool 20 with end effectors 32a, 32b for implementation within the scope of a further embodiment of an ultrasound robot 100 according to the invention and / or a further embodiment of a robot arm 10 according to the invention. The tool 20 is in particular a tool for ultrasound-assisted facet joint injection.

[0111] This tool 20 is particularly modular in design to support the use of different ultrasound transducers 32a and injection needles 32b.

[0112] The ultrasound transducer 32a is particularly designed to provide intraoperative images, for example, to correctly position the tip of the injection needle 32b at the facet joints of the spine. The ultrasound transducer 32a is releasably connected via the positive transducer mount 34a to an end-effector sensor 22a, particularly designed as a 6-DOF force-moment sensor, which can measure the interaction forces between the patient 106 and the ultrasound transducer 32a. The proximal side of the force-moment sensor is connected to the central structural part 52 of the tool 20.

[0113] The positioning and alignment of the needle guide 34b is achieved via an actuated translational degree of freedom 48 and an actuated rotational degree of freedom 50. A further actuated translational degree of freedom 40 is provided for moving the syringe 33b of the injection needle 32b along its longitudinal axis, with an end effector sensor 22b, in particular optional, detecting the interaction forces of the injection needle 32b. Preferably, a stereo camera 42 can be used to monitor movements of the patient 106 and provide an initial estimate for the positioning of the ultrasound transducer 32a. Integrated buttons 46 preferably serve as the input interface, and in particular, a ring of RGB LEDs 44 serves as the output interface for the user 102.

[0114] In general, it is advantageous to position and align the guide for the injection needle 32b as soon as the facet joint to be treated is clearly visible in the ultrasound image. The injection needle 32a should point towards the entrance to the facet joint, keep the path through the patient's tissue as short as possible, and run sufficiently close to the center of the ultrasound image, particularly since image quality decreases towards the edges. Since the injection needle 32a is intended to run in the image plane of the ultrasound image, this is a planar problem. Therefore, at least one rotational degree of freedom is preferred for the orientation of the needle guide 34a in the image plane. In addition, a second degree of freedom is advantageous to enable repositioning of the injection needle 32b without moving the ultrasound transducer 32a.This repositioning may be preferable if the injection needle 32b deviates from its desired path during insertion due to tissue conditions, and the planned injection site cannot therefore be reached. Movement of the ultrasound transducer 32a should be avoided, as this could impair registration between preoperative planning and the ultrasound image and, in addition, could contaminate the insertion site of the injection needle 32b with ultrasound gel.

[0115] Preferably, as shown in Figure 7, the tool 20 has a mounting option 62 for a stereo camera 60 or another, in particular similar, optical sensor. This sensor is mounted in particular such that it can detect the three-dimensional skin structure of the patient 106 in the vicinity of the ultrasound transducer 32b. The detected 3D surface can then be compared in particular with the data from the preoperative imaging, for example typically CT images, in order to identify the approximate position of the facet joint to be treated. In autonomous operation, the ultrasound transducer 32b is then positioned near the patient's spine, in particular based on this position estimate, which can preferably contain errors due, among other things, to the movement of the soft tissue of the patient 106.Subsequently, ultrasound images of the spine in the vicinity of the estimated position are compared with the image data from the preoperative planning and registered. In particular, once the ultrasound transducer 32b is positioned so that its image section corresponds to the image from the preoperative planning, the needle guide can be positioned and aligned according to the plan.

[0116] The described approximate positioning of the ultrasound transducer using the stereo camera 42 can be performed autonomously, i.e., without intervention by the user 102. On the other hand, it particularly reduces the search space for registering the ultrasound images and the preoperative image data. Since this registration is complex and computationally intensive due to the different imaging modalities, particularly preoperative CT images and intraoperative ultrasound images, the risk of errors and the computational effort can be reduced.

[0117] Since in particular the user 102 is to interact directly with the tool 22, the latter preferably has a user interface suitable for this purpose, consisting of input interface 46 and / or output interface 44.

[0118] The input interface 46 should, in particular, enable navigation through a simple menu structure, which is why 20 buttons, such as up, down, and confirmation / level change, were integrated into this tool. However, other interfaces such as thumbsticks, directional pads, or a touchscreen can also be used.

[0119] The output interface 44 is intended, in particular, to provide feedback to the user 102 about the current system status. In the present system, an RGB LED ring 44 is preferably provided for this purpose, particularly in the area of ​​the robot interface 46. Other possible designs would include, for example, individual status LEDs or a small display.

[0120] Figure 8a shows a sectional view of a tool 20, in particular a partial tool 20, with an end effector 32b for implementation within the scope of a further embodiment of an ultrasonic robot 100 according to the invention and / or a further embodiment of a robot arm 10 according to the invention. The partial tool 20 from Figure 8a is preferably a detailed view of section VIII from Figure 7.

[0121] Figure 8b shows a perspective, side view of the tool 20 from Figure 8a, in particular with transducer 32a, attachment 34a and sensor 22a.

[0122] The ultrasonic transducer 32a is connected to the distal side of an end-effector sensor 22a, in particular designed as a 6-DOF force-torque sensor, via a transducer mount 34a with a form-fit and / or friction-fit connector consisting of the elements 35a, 35b and a mounting plate 35c. The proximal side of the end-effector sensor 22a is connected to the central structural part 52 of the tool 20. The housing 21 of the tool 20 is designed in particular such that it does not touch the distal sensor side in order not to impair the measurement. In particular, both the latch 35a, which can be fixed via a hinge 64 and a knurled screw 56, and the negative mold 35b are transducer-specific, while the remaining components of the transducer mount 34a, in particular, can be used for various models of ultrasonic transducers 32a.

[0123] The preferred use of a separate mounting plate 35c allows the transducer mount 34a to be replaced when the ultrasonic transducer 32a is replaced without having to loosen the screw connection on the actual sensor. Since assembly errors, e.g., incorrect screw length or excessive torque, can lead to damage to the end effector sensor 22a during this screw connection, this particularly reduces the risk of damage. The attachment of the model-dependent transducer mount 34a to the mounting plate 34a can preferably be removed without tools, e.g., using click fasteners, magnets, or knurled screws. Likewise, the locking mechanism of the transducer mount 34a can preferably be fixed without tools.If the transducer attachment 34a is designed to be form-fitting to the ultrasonic transducer 32a, after a one-time calibration between the transducer position and the transducer attachment 34a, repeated insertion and removal of the ultrasonic transducer 32a is possible without the need for a calibration between the transducer position and the transducer attachment 34a each time.

[0124] To avoid disruptive forces from a cable 58 of the ultrasonic transducer 32a (see Fig. 7), it is preferable that the cable 58 be routed tension-free to the proximal side of the end effector sensor 22a and secured there, for example, by means of a clamp 60 (see Fig. 7). Since the ultrasonic transducer 32a can only move minimally in the transducer mount 34a, the disruptive forces and torques then occurring due to the cable 58 are, in particular, almost constant and can be easily taken into account when processing the sensor values.

[0125] The transducer attachment 34a is preferably located outside the housing 21 of the tool 22. This allows the ultrasonic transducer 22a to be attached and removed without opening the housing 21. This avoids possible damage to or contamination of the components inside the housing. In this case, it is preferred that there is an opening in the housing 21 in the area of ​​the end effector sensor 22a in order to prevent the force measurement from being impaired by the housing 21. To seal this opening against dirt and / or liquids, a seal is preferably provided which either functions without contact, e.g., a labyrinth seal, and / or has the lowest possible rigidity, e.g., silicone foam. This minimizes the disruptive forces and moments transmitted from the housing to the end effector sensor 22a.

[0126] Figure 9 shows a kinematics for implementing an embodiment of an ultrasound robot 100 according to the invention, an embodiment of a robot arm 10 according to the invention and / or a method according to the invention for controlling a robot arm 10. The kinematics in Figure 9 are used in particular for positioning and orienting the injection needle within the image plane of the US transducer.

[0127] Shown is a closed kinematic chain with two actuated degrees of freedom for positioning and aligning the needle guide 34b: The alignment of the needle guide 34b is achieved in particular via a translational actuated degree of freedom 502 and a rotational actuated degree of freedom 503, which are coupled to each other via two passive joints 504, 505. The translational degree of freedom 502 adjusts in particular the inclination of the needle guide 34b, while the rotational degree of freedom 503 sets the distance of the needle guide 34b from the ultrasound transducer 32a along a circular path. Since the rotational degree of freedom 503 preferably only carries out small angular changes, the needle guide 34b is moved predominantly horizontally by it and is only minimally lifted from the skin of the patient 106, whereby in particular the vertical movement for deflections up to 10° is less than 10% of the horizontal movement due to the trigonometric relationships.The needle 33b can be moved in particular relative to the needle guide 34b by a separate translational degree of freedom 508.

[0128] Since high rigidity of the needle guide is desirable, a closed kinematic chain with two driven degrees of freedom 502, 503 was chosen in the embodiment shown in Figure 9. Both degrees of freedom 502, 503 have a limit switch, particularly at one end of their range of motion, to enable an initialization run after the tool 20 is switched on. The range of motion of the needle guide 34b changes depending on the dimensions of the actuated degrees of freedom 502, 503.

[0129] Figure 10 shows a representation of a further tool variant, in particular a partial tool 20, for implementation within the framework of a further embodiment of an ultrasonic robot 100 according to the invention and / or a further embodiment of a robot arm 10 according to the invention.

[0130] A preferred motor 601 drives a toothed belt 602, which is positively connected to carriage 603 on linear rail 604. The pretension of toothed belt 602 is achieved, in particular, via an eccentric roller 605. Near the patient-side end of linear rail 604, an intermediate element 606 for securing needle guide 34b is mounted. In the illustrated embodiment of carriage 603, it is equipped with a magnet 608 for attaching a syringe attachment.

[0131] Preferably, the planned tool 20 should also support autonomous execution of the facet joint injection. For this purpose, it is preferred that the translational degree of freedom for the needle advancement be driven, for example, by means of motor 601 according to Figure 10.

[0132] At one end of the rail 604, there is, in particular, a limit switch to enable an initialization run after the tool 20 is switched on. The injection syringe 32b is attached to the carriage 063 in such a way that the syringe needle 33b is aligned with the needle guide 34b at the patient-side end of the profile rail guide.

[0133] Figure 11a shows a sectional view of another tool variant, in particular a partial tool 20, for implementation within the scope of another embodiment of an ultrasound robot 100 according to the invention and / or another embodiment of a robot arm 10 according to the invention. Preferably, particularly in the embodiment according to Figure 10, a parting plane is provided in the syringe attachment to enable sterile packaging ("draping") of the tool 20 during the surgical procedure. Both the injection needle insertion site and its surroundings must be kept sterile during a procedure, as must all system components that come into contact with it. The latter applies in particular to the injection needle 32b and the needle guide 34b.Since the tool 20 and the robot structure 12 are generally not sterilizable due to the electronic components they contain and their complex geometry, it is preferable to wrap them in a sterile drape during the surgical procedure. Preferably, the ultrasound transducer 32a either must not touch the puncture site during the procedure or must also be sterilely draped. Thus, it is preferable that the injection needle 34a is always located outside the sterile drape, while the rest of the tool 20 is located inside.

[0134] Figure 11a shows a possible embodiment, particularly based on the embodiment according to Figure 10, wherein the carriage 701 and syringe attachment with elements 702, 703 are designed separately and wherein the parts are coupled by means of magnets 704. The sterile drape can be passed between the two magnets 704 without being damaged.

[0135] In an alternative embodiment to the embodiment in Figure 11a according to Figure 11b, an intermediate element is inserted into the sterile drape in the area of ​​the syringe attachment. This can be, for example, a plastic frame. Depending on the embodiment, the tool 20, the intermediate element, and the syringe attachment 34b can be connected via various mechanisms, preferably those that can be fixed and released without tools, such as magnets, snap fasteners, or screws. Although this alternative solution is technically more complex, it is particularly advantageous if an electrical interface is also to be routed through the drape at this point.

[0136] A circuit board with several spring contact pins 706 and two spring-loaded pressure pieces 707 are attached to the carriage of the linear guide 705, or, for example, to another component located inside the drape. When draping the system, the two-part plastic frame with elements 708, 709, which is fixed in an opening in the drape, is first pushed onto the carriage 701 until the preferably slightly beveled sides of the carriage 701 come into contact with the also preferably slightly beveled sides of the recess in the plastic frame. This blocks all degrees of freedom except horizontal translation. By engaging the balls of the spring-loaded pressure pieces 710 in recesses in the plastic frame, this last degree of freedom is also blocked. A circuit board with contact pads on both sides 711 is already fixed in advance within the two-part plastic frame.Likewise, the sterile drape has already been secured in the tongue-and-groove connection 712 between the two frame parts. Now, the syringe attachment 713, with the attached circuit board and several spring contact pins 714, can be pushed horizontally into the right-hand recess of the plastic frame until the sides of the carriage 701, which are preferably slightly beveled, come into contact with the sides of the recess in the plastic frame, which are also preferably slightly beveled. Upon reaching the target position, the snaps 715 engage in the corresponding recesses in 719 and also block horizontal translation. The extensions 716 on the snaps 715 facilitate the release of the syringe attachment from the plastic frame.

[0137] The actuated mechanism for needle advancement is preferably equipped with an end effector sensor 22b, in particular designed as a force sensor, for measuring the force in the longitudinal direction of the injection needle 32b. This allows unexpected tissue conditions, e.g. scar tissue, and collisions with the bone of the spine to be immediately detected and the application of excessive forces to be prevented. The described sensor in particular has at least one measurement degree of freedom in the direction of the needle axis. However, sensors with more degrees of freedom can also be used, for example to be able to detect lateral forces on the needle as a result of patient movements. The end effector sensor 22b can be located either inside or outside the drape. When mounted inside the drape, the end effector sensor 22b is in particular no longer sterile packaged; however, forces acting on the drape can impair the measurement.When mounted outside the drape, such interference does not occur. However, the end-effector sensor 22b should be particularly sterile and thus either repeatedly sterilizable or a cost-effective disposable product. Furthermore, especially in this case, the power and communication lines of the end-effector sensor 22b should be routed through the sterile barrier.

[0138] Figure 12a shows a sectional view of a further tool variant, in particular of a partial tool 20, with an end effector 32b within the framework of a further embodiment of an ultrasonic robot 100 according to the invention and / or a further embodiment of a robot arm 10 according to the invention.

[0139] Figure 12a shows in particular an inexpensive disposable sensor for measuring the needle insertion forces.

[0140] The injection syringe 32b, which has a needle 33b, is fixed to the matching syringe holder 34b. This holder is movably mounted relative to the attachment 803 of the end effector sensor 22b, in particular designed as a force sensor.

[0141] In the embodiment according to Figure 12a, a bearing with translational mobility along two guide pins 805 is implemented. As soon as the forces along the needle axis exceed the weight of the syringe and syringe holder, the difference can be measured at the end effector sensor 22b and / or calculated as a moment equilibrium around the rotation axis based on the measured values ​​of the end effector sensor 22b. If forces below the weight of the syringe and syringe holder are to be detected, it is preferable to preload the syringe holder relative to the end effector sensor 22b, for example, using a spring-loaded pressure piece. In particular, the preload should be above the expected maximum weight of the syringe and syringe holder but significantly below the measurable maximum force of the force sensor.In addition, a further end effector sensor 808, for example a force measuring resistor, can be attached, particularly to the plunger of the syringe, using a suitable connecting element 807. This sensor measures, in particular, the forces applied by the user 102 to the plate 809 and thus monitors the maximum pressure applied during the injection of the medication. The central advantage of the concept shown, in addition to its fundamental usability for various injection applications, lies in the low price of the components used: For example, a single-axis MEMS force sensor is commercially available for around €30, suitable force measuring resistors for under €10, and a microcontroller board for evaluating the sensor signals also for under €10. Thus, the syringe attachment with the integrated sensor technology can be designed as a disposable component, which simplifies its sterilization.

[0142] Figure 12b shows a sectional view of a further tool variant, in particular of a partial tool 20, with an end effector 32b within the framework of a further embodiment of an ultrasonic robot 100 according to the invention and / or a further embodiment of a robot arm 10 according to the invention. The embodiment according to Figure 12b corresponds to the embodiment from Figure 12a, wherein in Figure 12b a bearing with rotational mobility around a shoulder fitting screw 806 is implemented instead of the bearing with translational mobility along two guide pins 805 (Figure 12a).

Claims

Claims Robot arm (10), in particular hands-on robot arm, with - a robot structure (12), wherein the robot structure (12) has an arm link chain (18) having at least one arm link (14) and at least one joint (16), and wherein the robot structure (12) further has a tool (20) connected to the arm link chain (18) for connection to at least one end effector (32); - at least one end effector sensor (22) for detecting forces and / or moments acting on an end effector (32) connected to the tool (20); and - at least one structural sensor (24) for detecting forces and / or moments acting on the robot structure (12). Robot arm (10) according to claim 1, characterized in that the at least one end effector sensor (22) and / or the at least one structural sensor (24) is: a force sensor, a moment sensor, or a force-moment sensor with two to six degrees of freedom. Robot arm (10) according to claim 1 or 2, characterized in that the arm link chain (18) has a plurality of arm links (14), each with joints (16) arranged therebetween. Robot arm (10) according to one of claims 1-3, characterized by a structural sensor (24) between the tool (20) and the arm link chain (18) for detecting forces and / or moments acting on the tool (20). Robot arm (10) according to one of claims 1-4, characterized in that for at least one arm member (14), in particular for each arm member (14), a structural sensor (24) for detecting forces and / or moments acting on the respective arm member (14) is provided, preferably connected to the respective arm member (14). Robot arm (10) according to one of claims 1-5, characterized by at least one end effector (32) detachably or non-detachably connected to the tool (20). Robot arm (10) according to claim 6, characterized in that an end effector sensor (22) for detecting forces and / or moments acting on the tool (20) is arranged between the at least one end effector (32), in particular between each end effector (32), and the tool (20). Robot arm (10) according to one of claims 1-7, characterized by a tool interface (26) arranged between the arm link chain and the tool (20) for, in particular detachably, connecting the tool (20) to the tool interface (26).Robot arm (10) according to claim 8, characterized in that a structural sensor (24) for detecting forces and / or moments acting on the tool interface (26) is arranged between the arm link chain (18) and the tool interface (26). Robot arm (10) according to one of claims 1-9, characterized by a control unit (23) for controlling the robot arm (10), wherein the control unit (23) is configured to receive and, in particular, process the forces and / or moments detected by the end effector sensor (22) and the structural sensor (24). Robot arm (10) according to claim 10, characterized in that the robot structure has at least one virtual fixture (318), in particular for limiting and / or damping the movement of the robot arm (10), wherein the control unit (23) is configured to adjust the at least one virtual fixture (318) based on the forces and / or moments detected by the end effector sensor (22) and the structure sensor (24). Ultrasonic robot (100) with a robot arm (10) according to one of claims 1-11, an ultrasonic transducer (32a) connected to the tool (20) as the end effector (32), and preferably an injection needle (32b) connected to the tool (20) as the further end effector (32). Method for controlling a robot arm (10), in particular a robot arm (10) according to one of claims 1-11 or an ultrasonic robot (100) according to claim 12, comprising the steps: - detecting forces and / or moments acting on an end effector (32) of the robot arm (10), - detecting forces and / or moments acting on a robot structure (12) of the robot arm (10), - Determining, in particular calculating, interaction forces and / or interaction moments of the robot arm (10) based on the detected forces and / or moments. Method according to claim 13, characterized by the further step: - Output of the interaction forces and / or interaction moments, in particular to an overall control of the robot arm (10).

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