Control unit for a surgical instrument

Abstract

The invention relates to a control unit (10) for a surgical instrument (1) with an instrument wrist (2) mechanically coupled to an end-effector (3) of the surgical instrument (1), comprising: a master handle (20) configured to be held by a surgeon. To provide a control unit that improves the operability by the surgeon, in particular by enabling intuitive, real-time mapping of the surgeon's hand movements to corresponding articulation of the surgical instrument, motion sensors (22) are included in the master handle (20) to detect pitch (P), and yaw (Y), and preferably roll (R) movements of the surgeon's hand, and a motor unit (30) is coupled to the master handle (20), the motor unit (30) comprising at least one motor (32) to map the detected pitch (P), and yaw (Y), and if applicable roll (R) movements of the master handle (20) to desired movements of the instrument wrist (2) and to create corresponding mechanical motion (p, y, r) of the surgical instrument (1), a transmission interface (40) for transmitting the motion (p, y, r) to the instrument wrist (2) of the surgical instrument (1) to move the end-effector (3).

Description

[0001] Control unit for a surgical instrument

[0002] Technical Field

[0003] The invention relates to a control unit for a surgical instrument with an instrument wrist.

[0004] Background

[0005] Today, known approaches to robotic-assisted laparoscopic surgery include Da Vinci, Dex Surgical, and HandX. Each implements a master-slave architecture that translates surgeon hand movements on a proximal control interface (master) to distal instrument wrist articulation (slave) with at least three degrees of freedom (roll, pitch, and yaw) enabling "around the corner" tissue manipulation in confined anatomical spaces. All three systems employ motorized actuation and electronic control units to replicate human wrist dexterity beyond the limitations of conventional laparoscopic instruments, operating through standard trocar ports (hollow tubes inserted through small abdominal incision to provide access points for laparoscopic instruments and cameras), while visualized via endoscopic cameras. Da Vinci utilizes a remote console separated from the patient, while Dex Surgical and HandX both function as handheld bedside devices. Despite their divergent form factors, they share the common objective of enhancing surgical precision through intuitive motion scaling and tremor filtration. However, they also share fundamental challenges: the translation of surgeon hand motion to instrument wrist movement often lacks intuitive correspondence, creating cognitive burden and motion interference, while the integration of motors, control electronics, and mechanical linkages results in substantial weight that causes surgeon fatigue and discomfort during prolonged procedures, especially in handheld configurations due to complex mapping, creating cognitive burden and motion interference.

[0006] In particular, the da Vinci system implements a master-slave architecture where the surgeon operates from a remote console manipulating mastercontrollers that translate hand movements to (e.g. EndoWrist) instruments with three degrees of freedom at the wrist (roll, pitch, yaw) plus grip, providing seven total degrees of freedom (DOF). The surgeon console requires the surgeon's head to be positioned in a 3D viewer for hand controller activation, which is detected by infrared sensors that trigger three audible beeps when the head is properly positioned, enabling the master controllers. Hand controls utilize thumb and middle finger loops with index finger free for clutch buttons, while foot pedals control camera movement, electrocautery, and clutch functions. The system employs motion scaling up to 5:1 and tremor filtration for sub-millimetre precision, but implements haptic-isolated control where force feedback is deliberately minimized to filter out body wall forces and torques, creating sensory isolation that separates the surgeon from direct patient contact and bedside team communication.

[0007] Dex Surgical Instrument is a handheld robotic-assisted laparoscopic instrument comprising a mechatronic handle interface and motorized articulating shaft, wherein the surgeon's hand movements are translated through a control handle to actuate a distal wrist mechanism providing seven degrees of freedom. The instrument-to-manipulator interface consists of an electronic control unit that processes surgeon inputs and drives cable-actuated joints at the instrument tip, enabling infinite rotation and precise tissue manipulation while preserving direct haptic feedback. However, the translation of surgeon hand motion to instrument wrist articulation requires cognitive adaptation as the mechanical linkage introduces non-intuitive kinematic mapping, and motion interference between the master handle and slave mechanism can reduce operability in complex manoeuvres.

[0008] Further, HandX from HumanXtensions is a software-driven electromechanical handheld surgical platform comprising a reusable control handle and detachable single-use instrument tips, wherein the surgeon interface utilizes natural grip positioning and finger-actuated controls to command eight degrees of freedom, of which are four manual and four motorized controls. The handpiece-to-instrument interface employs embedded microprocessorsthat interpret surgeon inputs and independently control motorized articulation at the distal tip, achieving up to 540° rotation through a 5mm shaft. However, the software-mediated translation between surgeon hand motion and instrument wrist movement introduces latency and non-linear mapping that lacks intuitive correspondence, with motion interference between manual and motorized axes complicating precise control in clinical applications. Further, the concentration of motors, batteries, and control electronics within the handheld unit creates substantial weight that exceeds traditional laparoscopic instruments, resulting in surgeon discomfort and fatigue despite the ambidextrous grip design and ergonomic positioning features.

[0009] Summary

[0010] An object of the present invention is thus to provide a control unit that improves the operability by the surgeon, in particular by enabling intuitive, real-time mapping of the surgeon's hand movements to corresponding articulation of the surgical instrument.

[0011] This object is solved by the subject-matters defined in the attached independent claim. Advantageous embodiments are defined in the dependent claims. Note that the features mentioned in the introductory part of this description may individually or in any combination thereof also be provided in the presently disclosed solution, if not mentioned or evident otherwise.

[0012] According to the invention, a control unit for a surgical instrument with an instrument wrist mechanically coupled to an end-effector of the surgical instrument comprises a master handle designed to be held by a surgeon. The master handle includes motion sensors to detect pitch, yaw, and preferably roll movements of the surgeon's hand. The control unit further comprises a motor unit coupled to the master handle, wherein the motor unit comprises at least one motor that maps the detected pitch, yaw, and roll movements into desired mechanical motions of the instrument wrist. The control unit further includes atransmission interface for transmitting these mechanical motions to the instrument wrist of the surgical instrument to move the end-effector.

[0013] The integration of motion sensors for pitch, yaw, and / or roll enables precise and responsive control of the surgical instrument's wrist, allowing for complex manoeuvrers in confined surgical spaces. The use of a dedicated motor unit ensures accurate mapping of the surgeon's hand movements to the instrument's mechanical actions, minimizing latency and enhancing operational reliability. The transmission interface ensures that the translated mechanical motions are efficiently and reliably transferred to the instrument wrist, maintaining the fidelity of the surgeon's intended movements.

[0014] The master handle may include a grasp to accommodate the surgeon’s hand. Motion sensors refer to devices that detect angular displacements of the master handle in specific directions, in particular but not limited to pitch, yaw and roll. A motor unit denotes a system of one or more motorized actuators that convert detected movements into mechanical forces or motions. A transmission interface may describe a mechanism that transfers mechanical motion from a source, such as the motor unit, to a target component, like the instrument wrist, ensuring alignment and synchronization of movements. The transfer may be carried out through electrical or mechanical means.

[0015] The invention addresses the technical problem of non-intuitive kinematic mapping and motion interference inherent in prior art robotic surgical systems, which rely on mechanical linkages, software-mediated translation, or indirect motion detection (e.g., head-triggered controls or segmented input devices). By integrating motion sensors directly into the master handle to detect pitch, yaw, and roll movements in real-time, the invention enables a more direct and intuitive correspondence between the surgeon's hand movement and gestures and the instrument wrist's articulation, reducing cognitive burden and operational complexity. The dedicated motor unit and transmission interface streamline the translation of detected movements into precise mechanical motion, possibly by scaling the detected movement when outputting thedesired movement of the surgical instrument, avoiding the latency, non-linear mapping, and weight-related fatigue issues caused by prior art's reliance on external consoles, software mediation, or bulky motor-electronic components. This design enhances surgical precision and ergonomics without requiring the surgeon to adapt to non-intuitive control schemes or endure the physical strain of handling heavier, cognitively complex devices.

[0016] The surgical instrument is preferably an articulated surgical instrument. An articulated surgical instrument is a type of advanced medical device designed with multiple segments or joints that can move independently, enabling enhanced dexterity and precision in surgical procedures. Unlike rigid instruments, articulation allows the instrument’s end-effector to navigate complex anatomical structures and reach otherwise inaccessible areas, such as deep recesses or tortuous pathways in the body. This is particularly helpful in minimally invasive surgeries, where small incisions and limited visibility require tools capable of adapting to three-dimensional surgical fields. For example, in robotic-assisted surgery, an articulated instrument might bend or pivot at multiple points to align with the target tissue while avoiding surrounding organs or blood vessels. The articulation is typically achieved through a combination of mechanical linkages, motorized joints, and software-controlled feedback systems, which work in tandem to ensure smooth, tremor-free motion and precise angular adjustments. Preferably the master handle is connected to the motor unit by a Cardan-type joint, wherein the axes of the joints intersect in a single point remote to the joints. End-effector refers to the active component of the surgical instrument that directly interacts with tissues, such as a cutting blade, grasper, needle driver or bone cutting instruments. For example, cutting blades may pivot around a fulcrum, creating a swinging motion with a defined angular range to control cutting depth and precision.

[0017] In a further embodiment, the control unit may be configured such that the roll, pitch, and yaw axes of the detected roll, pitch, and yaw movements of the surgeon's hand of the master handle intersect within a spherical volume centred in the surgeon's palm. This design enables intuitive one-to-onemapping of the surgeon's hand movements to the instrument wrist and ensures that the movement axes align with the natural pivoting points of the hand, reducing mechanical resistance and enhancing the intuitiveness of the control. By centralizing the axes within the palm, the system minimizes unintended rotational drift during operation, which improves precision in delicate surgical tasks. Additionally, the compact arrangement of intersecting axes allows for a more ergonomic handle design, accommodating a wider range of hand sizes and reducing user fatigue during prolonged procedures.

[0018] In another embodiment, the spherical volume may have a diameter in the range of up to 5 cm, especially in the range of up to 4 cm, in particular a diameter of 3 cm. A minimum size of the diameter of the spherical volume may be at least 1 cm, more preferably 2 cm. This specific sizing of the spherical volume ensures compatibility with the anatomical constraints of a human hand, allowing the control unit to remain compact while accommodating natural hand movements. The limited diameter minimizes spatial requirements for the handle, which is particularly advantageous in minimally invasive surgical scenarios where workspace is restricted. By defining a precise range and / or a preferred size, the design balances ergonomic usability with mechanical efficiency, ensuring that the intersection of movement axes remains within a physiologically intuitive volume for the surgeon. A defined diameter also standardizes the control unit's dimensions, facilitating consistent user experiences across different instruments and reducing the risk of operational errors due to unfamiliar handle geometries.

[0019] In an additional embodiment, the master handle may be configured to include at least two joints, in particular wherein the joints can enable independent rotational movements in accordance with the detected movements of pitch, yaw, and / or roll. This arrangement allows for decoupling of rotational axes within the handle, ensuring that movements in one direction (e.g. pitch) do not interfere with movements in another direction (e.g. yaw or roll). The independent rotational capability of the joints enhances the precision of motion mapping between the surgeon's hand and the surgical instrument's wrist,reducing mechanical cross-talk and improving the fidelity of control.

[0020] Additionally, the modular design of the joints facilitates compact construction of the master handle while accommodating a wide range of natural hand motions, thereby optimizing both ergonomic usability and operational accuracy during surgical procedures.

[0021] In a further embodiment, the at least two joints may be arranged serially in a kinematic chain. This configuration ensures that rotational movements detected in the master handle are sequentially translated through the joints, maintaining mechanical continuity and reducing cumulative errors in motion mapping. The serial arrangement allows for precise alignment of each joint's axis with the corresponding movement requirement of the surgical instrument's wrist, enhancing the fidelity of control. Additionally, the modular design of serial joints facilitates compact integration within the control unit, optimizing space efficiency while maintaining flexibility in adapting to different surgical tasks. Data pathways of the motion sensors to the motor unit may be arranged parallel to each other along the kinematic chain.

[0022] The described mappings can be arranged in permutations of pitch (P), yaw (Y), and roll (R) that can be tailored to specific operational needs. For instance, in passive swapped configurations, the master handle's grasp control unit transmits movements in the order P — > Y — > R, which are then converted to r — > p — > y at the motor unit, with roll motions bypassing the motor unit entirely by utilizing a circular bearing as described further below. This direct coupling of roll reduces mechanical latency and energy consumption, ideal for tasks requiring rapid, unidirectional adjustments. In passive mirror mappings, the sequence Y — > P — > R in the master handle is mirrored as r — > p — > y, enabling symmetrical motion translation also without motor unit intervention, which simplifies calibration for mirrored anatomical structures.

[0023] Active swapped and active mirror mappings involve the motor unit processing all movements, allowing dynamic reordering of axes (e.g., P ^ Y ^ R to r ^ p— > y or Y — > P — > R to r — > p — > y). This adaptability ensures that the instrument's wrist can achieve complex articulations, such as rotating around non-orthogonal axes, which is helpful in confined surgical environments. The adapted master mapping for third-party effectors reorders the master handle's inputs as R — > Y — > P, aligning with external instruments that require nonstandard axis sequences. Finally, active straight mappings (R — > P — > Y to r — > p — > y) preserve the natural anatomical order of human hand movements, minimizing the cognitive load on surgeons during procedures.

[0024] Collectively, these mappings demonstrate the system's ability to decouple input and output axes, reduce mechanical interference, and optimize precision while accommodating diverse surgical requirements and third-party compatibility. It is possible to introduce additional axes of movement that may be incorporated in the kinematic chain. The control unit may even have more axes than the surgical instrument, allowing for a finer adjustment of the surgical instrument’s end-effector.

[0025] In a further configuration, the master handle may be configured to provide pitch and yaw degrees of freedom, especially allowing the surgeon to manipulate the surgical instrument. Additional degrees of freedom can be integrated into the master handle. For example, by incorporating a third joint dedicated to roll movement, a full three-dimensional rotational control of the handle can be enabled. Furthermore, the master handle may include further joints, each corresponding to an additional degree of freedom, such as lateral displacement or gripping motion, to expand the range of manipulative capabilities. The inclusion of these joints ensures that the surgeon's hand movements are accurately translated into complex, multi-axis motions of the surgical instrument, enhancing dexterity and adaptability in intricate procedures. The modular arrangement of joints allows for scalable customization of the handle's functionality, accommodating diverse surgical requirements while maintaining mechanical clarity. By decoupling each degree of freedom into independent joints, the system minimizes mechanical couplingerrors, ensuring precise and intuitive control even during simultaneous multiaxis operations.

[0026] In a further aspect of the invention, the master handle may be configured to include a forceps grip, in particular wherein the forceps grip can translate the surgeon's finger actuation into mechanical action at a surgical instrument's end-effector. This design enables direct and intuitive control of the endeffector's functional movements, such as grasping or cutting, by leveraging natural finger motions. The forceps grip ensures a high degree of kinematic accuracy, minimizing the risk of unintended actuation or delayed response during critical surgical steps. Additionally, a mechanical linkage between finger actuation and end-effector action can enhance tactile feedback, allowing the surgeon to perceive resistance or force applied at the surgical site with greater precision. The integration of the forceps grip into the master handle further optimizes the ergonomic layout, consolidating control functions within a compact and user-friendly interface. Alternatively, or additionally, the master handle may include at least one input control to control the motion of the endeffector and / or for configuration purposes such as scaling factors to directly control the scaling of the detected movements to the desired movements.

[0027] A forceps grip refers to a mechanical linkage within the handle that mimics the operational principle of a surgical forceps, converting manual finger movements into proportional mechanical motions. An end-effector denotes the terminal component of the surgical instrument, such as jaws or blades, that performs the actual cutting, grasping, or other functional tasks during a procedure. Accordingly, the at least one input control may be configured to mimic the design and / or the movement of the end-effector.

[0028] The forceps grip can be ergonomically designed to minimize fatigue during prolonged surgical procedures. A contoured and / or adaptive shape of the forceps grip can be designed to align with the natural anatomy of the surgeon’s hand, reducing physical strain during prolonged procedures. This approach can use biomechanical modelling to identify optimal angles andpressure distribution for different hand sizes, while adjustable segments (e.g., telescoping or rotating parts) can incorporate customizable features to adapt to individual ergonomic needs. For instance, a saddle-like structure can be employed to redistribute pressure away from the thumb and index or middle finger, offering an optional yet effective solution for minimizing localized fatigue and enhancing comfort during extended surgical tasks.

[0029] In yet a further embodiment, the transmission interface may be configured to include a surgical instrument interface, in particular wherein the surgical instrument interface can be adapted to couple with the surgical instrument through an interchangeable adapter. This design allows for modular compatibility with different types of surgical instruments, enabling the control unit to interface with a variety of end-effectors or tool configurations. The interchangeable adapter facilitates rapid tool exchange during procedures, reducing setup time and minimizing workflow disruptions. Additionally, the use of an adapter standardizes coupling mechanisms, ensuring consistent mechanical and electrical connections between the transmission interface and the surgical instrument. The modular architecture also simplifies maintenance and upgrades, as adapters can be replaced or modified independently of the core transmission interface. By decoupling the instrument-specific coupling from the transmission system, the design enhances flexibility for multiinstrument surgeries while maintaining precise force and motion transfer.

[0030] A surgical instrument interface refers to a component of the transmission system that establishes mechanical or electrical connectivity between the control unit and the surgical instrument. An interchangeable adapter denotes a modular coupling element that adapts the transmission interface to different surgical instruments, ensuring compatibility through standardized or customizable attachment mechanisms.

[0031] In a further embodiment, the control unit may be configured to include a support unit, wherein the support unit can be designed to stabilize the surgical instrument during operation. The support unit may incorporate a built-inmechanical arm or counterbalance system that can automatically compensate for the weight of the instrument, reducing physical strain on the surgeon and allowing for more precise and controlled movements. This feature can be adjustable to accommodate different instrument weights, ensuring adaptability to a wide range of surgical tools and procedures. The integration of such a support mechanism enhances the ergonomic efficiency of the system, enabling the surgeon to maintain steady and fatigue-free operation over extended periods. Especially by dynamically balancing the instrument's weight, the system minimizes unintended vibrations or drift, thereby improving the accuracy of delicate manoeuvres. The adjustability of the compensation mechanism further ensures optimal performance across diverse surgical scenarios, from lightweight instruments requiring fine adjustments to heavier tools demanding robust stabilization. This design directly addresses ergonomic challenges in minimally invasive surgery while maintaining the precision required for complex procedures. The support unit may include a circular bearing allowing at least one of the movement axes of the surgeon’s hand to be carried out by the support unit instead of the master handle by moving the combined system of the control unit and the surgical instrument. This enables a direct link between movement of the surgeon’s hand and the instrument wrist. The movement of the support unit may preferably be the roll movement.

[0032] A mechanical arm denotes a robotic or articulated support structure capable of adjusting position and exerting controlled forces to offset the instrument's weight. A counterbalance system refers to a mechanism that uses springs, weights, or hydraulic elements to neutralize gravitational forces acting on the surgical instrument, ensuring effortless manoeuvrability.

[0033] In a further embodiment, the control unit may be configured to include a support unit, wherein the support unit can be mechanically coupled to the motor unit. This mechanical coupling ensures structural stability and efficient force transmission between the support system and the motor-driven components, enabling synchronized operation during instrument manipulation.The direct connection minimizes mechanical play or slack in the system, enhancing the precision of movements and reducing unintended deviations. Additionally, the integrated design allows for compact spatial arrangement, optimizing the system's footprint in surgical environments where space is constrained. By aligning the support and motor units mechanically, the system achieves improved load distribution, which directly translates to enhanced durability and reduced wear on individual components. A mechanical coupling may denote a direct physical connection between components, ensuring rigid or semi-rigid transmission of forces and motions.

[0034] In a further embodiment, the control unit may be configured to include a feedback system that transmits haptic, in particular tactile signals to the master handle using sensor data from the surgical instrument, providing the surgeon with real-time sensory information about tissue contact or force applied. Haptic signals are information-bearing stimuli delivered through the sense of touch. They consist of controlled tactile and kinaesthetic cues, such as vibration, force, pressure or motion, that convey events, states or commands to a user. Tactile signals are information-bearing stimuli that act specifically on the skin’s cutaneous receptors. This integration of sensor data into the haptic feedback loop enhances the precision of the procedure, as the operator can immediately respond to mechanical resistance or tissue deformation. It reduces the risk of overloading or tissue damage, particularly in delicate surgeries. Additionally, the dynamic adjustment of feedback intensity based on instrument-specific sensor data increases user-friendliness and flexibility. The combination of tactile and visual feedback optimizes hand-eye coordination, while real-time force data transmission supports controlled application of pressure or cutting movements. This configuration is particularly advantageous in minimally invasive procedures, where direct tactile sensation is limited.

[0035] A feedback system denotes a technical unit that converts sensor data into haptic or tactile impressions, enabling the user to perceive remote or non-visible processes physically. Real-time information describes data processedand transmitted to the user immediately after acquisition, without significant and / or notable delay. The sensor data may be coming from integrated sensors of the surgical instrument or additional sensors mounted to the surgical instrument and / or placed in proximity to the surgical instrument.

[0036] In a further embodiment, the control unit may be configured to include a feedback system that can include adjustable sensitivity settings, in particular to accommodate different surgical techniques or tissue types. This adaptability allows the surgeon and / or the system to dynamically adjust the intensity or responsiveness of tactile and / or haptic feedback based on the specific requirements of the procedure, such as the fragility of tissues or the precision needed for delicate manoeuvres.

[0037] In a further embodiment, the mapping by the motor unit can be configured to be adjustable based on the surgeon's hand position and / or the specific surgical task being performed, wherein the master handle allows for adjustable scaling of the detected motions. This adaptability of motion mapping enhances the system's flexibility, enabling it to respond to varying anatomical conditions or precision requirements. The scalable transmission of hand movements to instrument movements also reduces the surgeon's cognitive load, as complex maneuvers are simplified through targeted scaling. Particularly in minimally invasive procedures, where the workspace is limited, this feature enables more precise control by, for example, translating small hand movements in the master handle into larger or finer instrument movements. Additionally, dynamic adjustment to hand position supports ergonomics, allowing the surgeon to utilize an optimal range of motion during different surgical phases or patient positions. This design further increases safety by minimizing miscontrol caused by excessive scaling, especially in sensitive deep tissue areas. Roll, Yaw, and Pitch typically denote the rotational axes of the detected motions, which are transmitted via the master handle. Adjustable scaling of these axes enables targeted adaptation to the degrees of freedom of the surgical instrument.Further, the adjustment can be automated via machine learning algorithms trained on surgical data. This integration of data-driven models enables the system to dynamically adapt mapping parameters in real-time, optimizing precision and responsiveness based on historical or real-time procedural patterns. The use of machine learning enhances the system's ability to recognize and prioritize critical motion scaling for specific tasks, such as delicate dissection or force-sensitive suturing, while minimizing unnecessary adjustments during routine surgery. Additionally, continuous learning from surgical data improves long-term adaptability, allowing the system to refine its performance across diverse procedures and user preferences. This automation reduces manual calibration efforts, lowers cognitive load on the surgeon, and ensures consistent, task-specific accuracy, even in complex or variable surgical environments. The result is a more intuitive and responsive control interface that aligns with both anatomical constraints and procedural demands.

[0038] In a further embodiment, the motor unit can be configured to limit the range of motion of the surgical instrument's end-effector to prevent unintended tissue damage. This feature enhances procedural safety by restricting movement beyond predefined thresholds, particularly in anatomically sensitive or confined areas. By constraining the end-effector's range, the system reduces the risk of overextension, misalignment, or accidental contact with non-target tissues, which is very helpful in high-precision surgeries such as neurosurgery or delicate vascular interventions. The predefined limits can be dynamically adjusted based on real-time sensor data or surgical phase, ensuring compatibility with varying tissue properties and task requirements. This design supports both novice and experienced surgeons by minimizing human error and maintaining consistent adherence to safety protocols, even in complex or unpredictable environments.

[0039] Range of motion denotes the maximum displacement or angular movement permitted for the end-effector within a defined spatial or functional boundary. In the case of laparoscopic scissors, the motor unit may dynamically adjust thepivoting blades' angular range and integrates torque sensors to halt motion if excessive force is detected, ensuring precise tissue cutting while minimizing trauma. For electrocautery devices, the motor unit may enforce blade position limits and modulates motion based on thermal feedback, optimizing cauterization and cutting while preventing unintended tissue damage. When applied to robotic surgical tools, the motor unit may apply real-time angular constraints to the cutting edge, aligning blade movement with predefined anatomical trajectories to avoid deviations in delicate or confined surgical fields. In the context of needle drivers, the motor unit may restrict jaw angular motion and employs force-sensing feedback to pause or reverse action upon encountering resistance, enabling precise suture cutting without compromising adjacent tissue. Regarding bone-cutting instruments, the motor unit may limit blade oscillation and integrate pressure sensors to halt over-cutting, adapting to bone density measurements for safe, efficient bone sectioning.

[0040] In a further embodiment, the motion limitations can be adjusted via a user interface that may be accessible to the surgeon during the procedure. This adjustability allows for real-time optimization of the end-effector's movement constraints to match specific anatomical conditions or procedural requirements. By integrating a user interface, the risk of unintended interventions is reduced, as the surgeon can selectively modify parameters such as angular ranges, force thresholds, temperature or vibrations without losing direct control over the instrument. Additionally, this flexibility enhances precision in complex procedures, enabling dynamic adaptation to varying tissue conditions or unexpected anatomical constraints. The accessibility of the user interface also helps minimize the surgeon's cognitive load by providing real-time feedback and rapid adjustment options within a seamless workflow.

[0041] In a further embodiment, the motor unit can be configured to include a tremor filtering system, in particular comprising a mechanical tremor suppressor and / or a software-implemented low-pass filter to smooth hand movements, particularly in the 15Hz - 20Hz frequency range. This integration enhancesprecision by reducing unintended micro-movements and oscillations during delicate procedures, ensuring stable and intentional end-effector control. The mechanical tremor suppressor preferably dampens high-frequency vibrations, while the software filter dynamically attenuates motion in the specified frequency range, minimizing the risk of accidental tissue trauma. Especially combined, these features improve surgical safety and accuracy, especially in tasks requiring fine motor control, such as neurosurgery or vascular anastomosis, where even minor tremors could compromise outcomes.

[0042] Brief description of the figures

[0043] In the following, embodiments of the invention will be described with reference to the attached schematic figures. Features which correspond to one another with regard to their type and / or function may be assigned the same reference signs throughout the figures.

[0044] Fig. 1 shows a schematic illustration of a control unit according to a first embodiment of the invention.

[0045] Fig. 2 shows a schematic illustration of a control unit according to a second embodiment of the invention.

[0046] Fig. 3 shows a schematic illustration of a control unit according to a third embodiment of the invention.

[0047] Fig. 4 shows a schematic illustration of motion mapping in two passive embodiments

[0048] Fig. 5 shows a schematic illustration of motion mapping in two active embodiments

[0049] Fig. 6 shows a schematic illustration of motion mapping in an adapted active embodiment and in a straight active embodiment

[0050] Detailed description

[0051] Fig. 1 shows a control unit 10 in a schematic isometric view, comprising a master handle 20, a motor unit 30, and a transmission interface 40. Thecontrol unit 10 is designed to translate the surgeon’s hand movements into precise mechanical actions of a surgical instrument 1, which includes an instrument wrist 2 and an end-effector 3. The master handle 20 is ergonomically shaped to be gripped by the surgeon during surgery, featuring a dedicated centrally located grasp 21 for stable handling. A forceps grip 26 is positioned atop the grasp 21 , enabling the surgeon’s thumb to actuate the end-effector 3.

[0052] The master handle 20 further includes motion sensors 22 and at least two joints 24 arranged in a kinematic chain, allowing independent rotational movements in pitch P, yaw Y, and optionally roll R. The kinematic chain is a sequence of the joints 24 having decoupled axes of movements. These joints 24 are mechanically connected via structural elements 25 with a first joint 24, in this case revolving around the pitch axis P, of the kinematic chain linked to the grasp 21 and a final joint, in this case revolving around the yaw axis Y, connected to the motor unit 30. The structural element 25 between the grasp 21 and the first joint 24 is a round longitudinal collar, the structural element 25 between the first and second joints 24 is designed as an angled bracket and the structural element 25 between the second joint 24 and the motor unit 30 is designed as a straight bracket. The joints 24 and the structural elements 25 of the master handle 20 form an outer Cardan joint of the master handle 20.

[0053] The motor unit 30 processes sensor data from the motion sensors 22 located at the joints 24 to generate mechanical motion p, y for the surgical instrument 1, while a support unit 50 ensures stability during operation. The transmission interface 40 couples the motor unit 30 to the surgical instrument 1 via a surgical instrument interface 42 and an interchangeable adapter 44, enabling compatibility with different instruments.

[0054] The master handle 20 may be characterized by a spherical volume S centred in the assumed position of the surgeon’s palm, in which the axes of the movements R, P, Y, in this case only the pitch and yaw axes of the movements P, Y, of the handle’s movements should intersect. This ensuresthat the surgeon’s hand movements P, Y are intuitively mapped onto the instrument’s wrist without the need for complicated motions, thereby maintaining precision in translating hand movements to the surgical instrument’s 1 end-effector 3. In this example, the spherical volume S has a diameter d of 3 cm, a dimension derived from ergonomic studies to optimize natural hand motion while minimizing strain during prolonged use for most surgeons. The motion sensors 22 are strategically positioned at the joints 24 to monitor rotational movement, with the pitch and yaw joints 24 enabling independent manipulation of the instrument wrist 2. The grasp 21 is connected to the first joint 24 via a bent bracket 25, ensuring the surgeon’s palm remains centred within the spherical volume S. The forceps grip 26, located on top of the grasp 21 , transmits finger actuation to the end-effector 3 via the motor unit 30 and the transmission interface 40, allowing the surgeon to perform delicate tasks such as grasping or cutting.

[0055] The motor unit 30 processes the detected movements P, Y, R from the master handle 20 as well as from the forceps grip 26 and maps them to the surgical instrument’s 1 pitch p, yaw y, and roll r movements as well as the effector’s movement. In the current embodiment only the detected movements P and Y are mapped to the pitch p and yaw y of the end-effector. This mapping is achieved through at least one motor 32, which converts the sensor data into mechanical motion.

[0056] The support unit 50, which stabilizes the surgical instrument 1 during operation, particularly during high-precision manoeuvres, is mechanically coupled to the motor unit 30. The support unit 50 is designed to counteract external forces, ensuring the instrument remains steady even if the surgeon’s hand inadvertently shifts and supports the surgeon’s hand own weight when resting on the grasp 21. For this purpose, the support unit 50 comprises at least one fastening connector 52 to attach the support unit 50 to a supporting framework (not shown) or supporting beams (not shown). Further, the support unit 50 is configured as a circular bearing to allow movement, i.e. rotation, in a roll direction R, the support unit 50 having a stationary outer ring 54 and arotatable inner ring 56, the inner ring 56 being coupled to a housing 31 of the motor unit 30. This allows for a direct coupling of the roll movements R and r of both the control unit 10 and the surgical instrument 1.

[0057] The transmission interface 40, comprising a surgical instrument interface 42 and an interchangeable adapter 44, allows the control unit 10 to interface with various surgical instruments 1, enhancing its versatility. The interchangeable adapter 44 is particularly useful in multi-instrument procedures, enabling rapid tool changes without disrupting the surgical workflow.

[0058] Further, the master handle 20 can comprise a feedback system 28. The feedback system 28 enhances the surgeon’s tactile experience and precision. The feedback system 28 transmits tactile and haptic signals from the surgical instrument 1 back to the master handle 20, providing real-time feedback on forces and resistance encountered during surgery. This closed-loop system improves the surgeon’s sense of touch, reducing the risk of unintended tissue damage.

[0059] The motor unit 30 can include a tremor filtering system 36, preferably located inside the motor unit 30. The tremor filtering system 36 may comprise a mechanical tremor suppressor 37, e.g. a dampening element, and / or a low-pass filter 38, preferably software-implemented. The tremor filtering system 36 may combine the mechanical suppression and the low-pass filtering to smooth hand movements, particularly in the 15 Hz to 20 Hz frequency range, which corresponds to typical human tremor frequencies. By dampening these involuntary motions, the system ensures that only intentional movements are translated to the end-effector 3, further enhancing surgical accuracy.

[0060] Together, the components of the control unit 10 create a system that enhances surgical accuracy through ergonomic design and advanced motion control of the surgical instrument 1. The master handle’s 20 spherical volume S and kinematic chain ensure intuitive translation of hand movements into scaled actions of the end-effector 3, while the motor unit 30 and transmissioninterface 40 provide mechanical precision and adaptability. The support unit 50 and feedback system 28 further reinforce stability and tactile feedback, reducing the risk of errors. The interchangeable adapter 44 and modular design allow the control unit 10 to integrate seamlessly with a variety of surgical instruments 1 , making it a versatile tool in minimally invasive procedures.

[0061] In Fig. 2, a second embodiment of the control unit 10 according to the invention is shown. Only elements and components that differ are labeled in the drawing and described herein. The remaining elements, components and functions are the same as in the first embodiment shown in Fig. 1.

[0062] In the second embodiment shown in Fig. 2, the master handle 20 is modified to include an additional roll axis R, which is now realized through a dedicated joint 24 and a corresponding motion sensor 22. This roll joint 24, which is - in this example - positioned closest to the grasp 21 in the kinematic chain, allows the surgeon to initiate roll motions through subtle rotational adjustments of the wrist, which are captured by the dedicated motion sensor 22. This addition increases the dexterity of the system, particularly in tasks requiring fine rotational adjustments, such as reorienting the end-effector 3 for optimal tissue access.

[0063] This enhancement extends the kinematic chain of the master handle 20 to a sequence of roll R, pitch P, and yaw Y, with the grasp 21 connected to the roll joint 24. The roll joint 24 is mechanically linked to a pitch joint 24, which in turn connects to a yaw joint 24, culminating in a connection to the motor unit 30. A structural element 25 connecting the grasp 21 to the first joint 24 is designed as a round collar. A structural element 25 connecting the first joint 24 to the second joint 24 is designed as an angled bracket. A structural element 25 connecting the second joint 24 to the third joint 24 is also designed as an angled bracket. The introduction of the roll joint 24 allows for independent rotational movement around the roll axis R, enabling the surgeon tomanipulate the surgical instrument’s 1 roll motion r in addition to pitch p and yaw y.

[0064] The spherical volume S, previously defined by the intersection of pitch and yaw axes P, Y, now incorporates the roll axis R, ensuring that all three rotational axes intersect within the surgeon’s palm. This design maintains ergonomic efficiency by aligning the natural pivot points of the hand with the instrument’s movements, thereby enhancing intuitive control. Further, the forceps grip 26 also acts as a grasp 21 of the master handle 20, enabling the hand of the surgeon to rest on the forceps grip 26 while using two fingers to control the forceps grip 26. The spherical volume S is centred in a position inside the forceps grip 26.

[0065] The kinematic chain ensures that roll movements are decoupled from pitch and yaw, preventing unintended coupling between axes. This separation improves the accuracy of motion translation, as the motor unit 30 processes roll data independently via the dedicated sensor 22. The feedback system 28 also transmits tactile signals related to roll-specific forces, further refining the surgeon’s tactile perception. The tremor filtering system 36, which already dampens involuntary motions in the 15Hz to 20Hz range, now extends its suppression to roll-axis tremors, enhancing overall precision.

[0066] By integrating roll into the kinematic chain and assigning to it a dedicated sensor 22 and another joint 24, the system achieves a more comprehensive mapping of hand movements to the instrument’s degrees of freedom. This advancement supports complex surgical manoeuvres requiring simultaneous control of multiple axes. The modifications thus elevate the system’s versatility and precision in minimally invasive procedures.

[0067] In this embodiment shown in Fig. 2, the support unit 50 is detached from the motor unit 30. However, a connector element 33 protruding from the casing of the motor unit 30 can be seen that allows a support unit 50 to be attached to the motor unit 30.In Fig. 3, a third embodiment of the control unit 10 according to the invention is shown. Only elements and components that differ are labeled in the drawing and described herein. The remaining elements, components and functions are the same as in the first embodiment shown in Fig. 1.

[0068] In the third embodiment depicted in Fig. 3, the master handle 20 is modified to refine the structural configuration of its kinematic chain while maintaining the forceps grip 26 atop the grasp 21 as in the first embodiment. The structural elements 25 interconnecting the joints 24 of the master handle 20 exhibit distinct geometric adaptations compared to the embodiments shown in Figs. 1 and 2. Specifically, the structural element 25 between the grasp 21 and the first joint 24 (pitch axis P) is designed as a round longitudinal collar, akin to the configuration in Fig. 1. Further, the structural element 25 linking the first joint 24 (P) to the second joint 24 (yaw axis Y) is an angled bracket, whereas in Fig. 1, this intermediate element was also an angled bracket. The distinction lies in the structural element 25 connecting the second joint 24 (Y) to the third joint 24 (roll axis R), which is also an angled bracket, differing from the straight bracket used in Fig. 1 or 2. This angled bracket ensures a more compact alignment of the joints 24, optimizing spatial efficiency within the spherical volume S while preserving ergonomic alignment of the rotational axes.

[0069] The third joint 24 (roll axis R) in this embodiment is directly attached to the motor unit 30, eliminating the need for an intermediate structural element 25 that was present in the second embodiment. This direct coupling enhances mechanical rigidity and reduces potential play in the roll-axis transmission, thereby improving precision in translating subtle rotational adjustments of the surgeon’s wrist into the surgical instrument’s 1 roll motion r.

[0070] The spherical volume S, defined by the intersection of the pitch, yaw, and roll axes, remains centred within the surgeon’s palm inside the grasp 21, ensuring intuitive control. The angled brackets between the joints 24 and the direct connection to the motor unit 30 collectively reinforce the kinematic chain’sability to decouple roll movements from pitch and yaw, preventing unintended coupling and enhancing the accuracy of motion translation.

[0071] Fig. 4 to 6 show diagrams of possible configurations of the kinematic chain. The control unit 10 according to the invention may be arranged according to the configurations schematically illustrated in Fig. 4 to 6 to accommodate specific surgical requirements, such as passive or active axis reordering, third-party compatibility, or natural anatomical motion alignment. These examples, including passive swapped, active mirror, and adapted master configurations, highlight the system’s modular design and its ability to decouple input and output axes for optimized precision, reduced mechanical interference, and task-specific adaptability. Further configurations remain possible, as the control unit’s 10 architecture supports dynamic reordering of movement axes, direct coupling of certain motions, and integration of additional kinematic elements beyond those shown, enabling customization for diverse surgical environments, specialized instruments, or evolving procedural needs.

[0072] Fig. 4 first example (passive swapped) demonstrates a configuration where the master handle 20 transmits movements in the sequence P — > Y — > R to the motor unit 30, which then outputs r — > p — > y. Here, roll motions R are directly coupled via a circular bearing, circumventing the motor unit 30. This reduces latency and energy use, ideal for tasks requiring rapid roll adjustments. In Fig.

[0073] 4 second example (passive mirror), the master handle 20 maps Y — > P — > R to r — > p — > y, with roll R again bypassing the motor unit 30. This mirrored configuration simplifies calibration for anatomical structures requiring symmetrical motion translation.

[0074] Fig. 5 first example (active swapped) shows the motor unit 30 actively processing P — > Y — > R inputs to generate r — > p — > y outputs, enabling dynamic axis reordering. This allows the instrument wrist 2 to rotate around non-orthogonal axes, helpful in confined surgical spaces. In Fig. 5 second example (active mirror), the motor unit 30 mirrors Y ^ P ^ R to r ^ p ^ y, preserving the surgeon’s intent while adapting to mirrored anatomical layouts.Fig. 6 first example (adapted master) reorders the master handle 20’s inputs as R — > Y — > P, aligning with third-party effectors requiring non-standard sequences. In Fig. 6 second example (active straight), the motor unit 30 maps R ^ P ^ Y to r ^ p ^ y, preserving the natural anatomical order of hand movements to reduce cognitive load on the surgeon.

[0075] The figures above show that a control unit 10 according to the invention translates surgeon hand movements into precise surgical instrument actions via a kinematic chain with decoupled pitch, yaw, and roll joints. The motor unit 30 processes sensor data for mechanical motion, while the support unit 50 ensures stability. Modular configurations (Figs. 4-6) enable adaptable axis mapping, and feedback / tremor filtering enhance precision and tactile responsiveness in minimally invasive procedures.List of reference signs

[0076] 1 surgical instrument

[0077] 2 instrument wrist

[0078] 3 end-effector

[0079] 10 control unit

[0080] 20 master handle

[0081] 21 grasp

[0082] 22 motion sensors

[0083] 24 joints

[0084] 25 structural element

[0085] 26 forceps grip

[0086] 27 user interface

[0087] 28 feedback system

[0088] 30 motor unit

[0089] 31 housing

[0090] 32 motor

[0091] 33 connecting elements

[0092] 36 tremor filtering system

[0093] 37 mechanical tremor suppressor 38 software-implemented low-pass filter

[0094] 40 transmission interface

[0095] 42 surgical instrument interface

[0096] 44 interchangeable adapter

[0097] 50 support unit

[0098] 52 fastening connector

[0099] 54 outer ring

[0100] 56 inner ringP pitch of the master handle

[0101] R roll of the master handle

[0102] Y yaw of the master handle

[0103] p pitch of the surgical instrument r roll of the surgical instrument y yaw of the surgical instrument

[0104] S volume

[0105] d diameter

Claims

Claims1. A control unit (10) for a surgical instrument (1 ) with an instrument wrist (2) mechanically coupled to an end-effector (3) of the surgical instrument (1), comprising:a master handle (20) configured to be held by a surgeon,wherein the master handle (20) includes motion sensors (22) to detect pitch (P), and yaw (Y), and preferably roll (R) movements of the surgeon's hand, anda motor unit (30) coupled to the master handle (20), the motor unit (30) comprising at least one motor (32) to map the detected pitch (P), and yaw (Y), and if applicable roll (R) movements of the master handle (20) to desired movements of the instrument wrist (2) and to create corresponding mechanical motion (p, y, r) of the surgical instrument (1 ),a transmission interface (40) for transmitting the mechanical motion (p, y, r) to the instrument wrist (2) of the surgical instrument (1 ) to move the endeffector (3).

2. The control unit according to claim 1, characterized inthat roll, pitch, and yaw axes of the detected roll, pitch, and yaw movements of the surgeon's hand of the master handle (20) intersect within a spherical volume (S) centred in the surgeon's palm.

3. The control unit according to claim 2, characterized inthat the spherical volume (S) has a diameter (d) in the range of up to 5 cm, in particular the spherical volume (S) has a diameter (d) of 3 cm.

4. The control unit according to one of the previous claims, characterized inthat the master handle (20) comprises at least two joints (24), in particular wherein the joints (24) enable independent rotational movements in accordance with the detected movements (P, Y, R).

5. The control unit according to claim 4, characterized inin that the at least two joints (24) are arranged serially in a kinematic chain.

6. The control unit according to claim 4 or 5, characterized inthat the at least two joints are configured to provide pitch (P) and yaw (Y) degrees of freedom, especially allowing the surgeon to manipulate the surgical instrument.

7. The control unit according to one of the previous claims, characterized inthat the master handle (20) comprises a forceps grip (26), in particular wherein forceps grip (26) translates the surgeon's finger actuation into mechanical action at the surgical instrument’s (1) end-effector (3).

8. The control unit according to one of the previous claims, characterized inthat the transmission interface (40) comprises a surgical instrument interface (42) adapted to couple with the surgical instrument (1) in particular through an interchangeable adapter (44).

9. The control unit according to one of the previous claims, characterized infurther comprising a support unit (50), wherein the support unit (50) is configured to stabilize the surgical instrument (1) during operation.

10. The control unit according to claim 9, characterized inthat the support unit (50) is mechanically coupled to the motor unit (30).

11. The control unit according to one of the previous claims, characterized infurther comprising a feedback system (28) that transmits haptic signals to the master handle (20) using sensor data from the surgical instrument12. The control unit according to one of the previous claims, characterized inthat the mapping by the motor unit (30) is adjustable based on the surgeon's hand position and / or the specific surgical task being performed, in particular wherein the master handle (20) allows for an adjustable scaling of the detected motions (R, Y, P).

13. The control unit according to one of the previous claims, characterized inthat the motor unit (30) is configured to limit the range of motion of the surgical instrument's end-effector to prevent unintended tissue damage.

14. The control unit according to claim 13, characterized inthat the motion limitations are adjustable via a user interface.

15. The control unit according to one of the previous claims, characterized inthat the motor unit (30) includes a tremor filtering system (36), in particular including a mechanical tremor suppressor (37) and / or a software-implemented low-pass filter (38) to smooth hand movements, particularly in the 15Hz - 20Hz frequency range.

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