Patent Description:
In a surgical robotic system, a robotic arm that has a surgical tool attached to it its distal end is remotely operated by a surgeon. Applications include endoscopic surgery, which involves looking into a patient's body and performing surgery inside, for example the abdominal cavity, using endoscopes and other surgical tools that are attached to the ends of several robotic arms. The system gives the surgeon a close-up view of the surgery site, and also lets the surgeon operate the tool that is attached to the arm, all in real-time. The tool may be a gripper with jaws, a cutter, a video camera, or an energy emitter such as a laser used for coagulation. The tool is thus controlled in a precise manner with high dexterity in accordance with the surgeon manipulating a handheld controller.

In a typical surgical robotic session, there may be up to five arms that need to be ready for being deployed at a surgical robotic platform, such as a table or bed on which the patient is resting. Installed within each arm is a communications interface for receiving robotic commands from, and providing for example video data to, a computerized, surgical console at which the surgeon sits while viewing a display screen that shows the surgical site and while manipulating the hand controller. Also installed within each arm is arm joint driver and control circuitry, and tool driver and control circuitry; the arm joint driver and control circuitry can drive several motorized joints (actuators) to pivot or translate various links of the arm so that the distal end of the arm is moved to a desired position as dictated by a user command; the tool driver and control circuitry can drive for example a gripper or cutter actuator or an energy emitter in the surgical tool (as dictated by a user command. ) Electrical power that supplies the communications interface and the arm joint and tool driver and control circuitry may be delivered to the arm, via a power cable that is separate from the arm but connected to the arm at one end and to the surgical robotic platform at another end (e.g., to a power supply at the surgical table. ) Alternatively, power may delivered to the arm through the use of pogo pins that come into electrical contact at a physical interface between the arm and an arm adapter at the robotic platform, when the arm is attached to the arm adapter.

Robotic arms DLUS for performing surgical tasks are known from <CIT>. Therein disclosed are disposable loading units configured for mounting to a robotic arm and having at least one automatically actuated surgical tool for performing a surgical task. The robotic arm acts on the DLUs with the dexterity and mobility of a surgeon's hand and can be programmed via an actuation assembly to actuate the surgical tool to perform the surgical task. Actuation commands are transmitted by electrical signals via cables from the actuation assembly to an electro-mechanical assembly within the DLUs. The electro-mechanical assembly within each DLU is configured to move and operate the surgical tool for performing the surgical task.

A wirelessly chargeable and portable ultrasonic diagnostic device is known from <CIT>.

An embodiment is a surgical robotic arm having a wireless power supply interface to a surgical robotic platform. The arm has a proximal end portion and a distal end portion. The distal end portion is configured to receive a surgical tool. The proximal end portion is coupled to the surgical robotic platform, for example to an adapter of a surgical table on which a patient lies. The adapter adapts the surgical table to be coupled to the arm, so that the arm can be used for performing a surgery on the patient (while the patient is lying on the surgical table. ) In one embodiment, the functions of the adapter may be viewed as being provided by the platform. The arm may have several linkages and actuated (motorized) joints in between adjacent linkages. The linkages can thus be rotated about a pivot axis at each joint, or can otherwise moved, when power is supplied to arm joint driver circuitry that drives the actuators. The proximal end portion of the arm is also configured for being decoupled from the adapter, for storage of the arm until it is to be re-coupled for use during another surgical session at the platform.

To achieve wireless or contactless electrical power transfer between the surgical robotic platform and an electrical load in the arm, a resonant-mode transformer-coupled power converter is provided. The power converter has a primary side and a secondary side, where the primary side has a transformer primary coil that is in the adapter (of the platform), while the secondary side has a transformer secondary coil that is in the proximal end portion of the arm. Once the arm is coupled to the adapter, the primary and secondary coils are held at relative positions and orientations that enable mutual inductive coupling between them, for proper operation of the power converter which delivers the full power needed by the electrical load during the surgery. This avoids the need for pogo pins or separate power cables and power connectors, to deliver sufficient and reliable electrical power from the platform to the electrical load that is in the arm. This solution is especially desirable since the arm has to not only be coupled to the adapter, but then decoupled for storage once the surgery is over, and then recoupled to the adapter for another surgery, where this cycle repeats quite often (e.g., more than a handful of surgical sessions in a single day): the wireless power supply interface may be more reliable in the long term than electrical contact-based connectors or pogo pins which can degrade over time particularly at high current levels and are difficult to keep clean. Also, the no-contact wireless power supply interface may be washable in the operating room, another important convenience. The solution is also especially advantageous as there are several such arms that are coupled to the robotic platform and are needed for simultaneous operation during the surgery.

In one embodiment, the adapter at the robotic platform and the proximal end portion of the arm are configured so that the primary and secondary coils are fixed in position relative to each other once the arm has been coupled to the adapter, and remain in the same relative position while the arm is then used during a surgery.

In one embodiment, the adapter may have a pivot j oint. A mechanical latching mechanism is provided that latches the arm to the pivot joint in the adapter, in a detachable and re-attachable manner. The pivot joint in the adapter enables the arm to rotate about a pivot axis of the j oint. In that case, the secondary coil and the primary coil remain fixed in position relative to each other but move as one with the arm as the arm rotates around the pivot joint of the adapter.

As mentioned above, an electrical load in the arm is coupled to the output of the secondary side of the power converter. The load may include a communications interface and motor and energy emitter driver circuitry, where the latter drives several actuators (at multiple joints including one or more at the surgical tool) and, if attached, an energy emitting surgical tool. The driving is in accordance with several arm linkage joint control signals and one or more tool control signals, that are received by the communications interface, for example from a control tower. The control tower may have translated user commands received from a surgical console (signals that are sensing the orientation or position of a handheld controller), and based on robotic feedback information from the arm (e.g., accelerometer output data, thermal sensor output data, etc.) into robotic commands (arm linkage joint control signals in the arm's joint space, and one or more tool control signals) for the arm.

In one embodiment, the actuator control signals as well as any other control signals that are not part of the wireless electrical power delivery interface to the arm (which may be a resonant mode transformer coupled power converter as described above) are received and transmitted by the communications interface through a communications cable that may run from the arm to the control tower <NUM>. Such a communications cable is thus in addition to the wireless power delivery interface, at each arm. The communications interface may also give robotic status feedback to generate the next command, and other status such as power consumption, temperature from a sensor in the arm or in the tool, and position from an accelerometer in the arm or in the tool.

The above summary does not include an exhaustive list of all aspects of the present invention. It is contemplated that the invention includes all systems and methods that can be practiced from all suitable combinations of the various aspects summarized above, as well as those disclosed in the Detailed Description below and particularly pointed out in the claims filed with the application. Such combinations have particular advantages not specifically recited in the above summary.

The embodiments of the invention are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to "an" or "one" embodiment of the invention in this disclosure are not necessarily to the same embodiment, and they mean at least one. Also, in the interest of conciseness and reducing the total number of figures, a given figure may be used to illustrate the features of more than one embodiment of the invention, and not all elements in the figure may be required for a given embodiment.

Several embodiments with reference to the appended drawings are now explained. Whenever the shapes, relative positions and other aspects of the parts described in the embodiments are not explicitly defined, the scope of the invention is not limited only to the parts shown, which are meant merely for the purpose of illustration. Also, while numerous details are set forth, it is understood that some embodiments of the invention may be practiced without these details. In other instances, well-known circuits, structures, and techniques have not been shown in detail so as not to obscure the understanding of this description.

Referring to <FIG>, this is a pictorial view of an example surgical robotic system <NUM> in an operating arena. The robotic system <NUM> includes a user console <NUM>, a control tower <NUM>, and one or more surgical robotic arms <NUM> at a surgical robotic platform <NUM>, e.g., a table, a bed, etc. The system <NUM> can incorporate any number of devices, tools, or accessories used to perform surgery on a patient <NUM>. For example, the system <NUM> may include one or more surgical tools <NUM> used to perform surgery. A surgical tool <NUM> may be an end effector that is attached to a distal end of a surgical arm <NUM>, for executing a surgical procedure.

Each surgical tool <NUM> may be manipulated manually, robotically, or both, during the surgery. For example, the surgical tool <NUM> may be a tool used to enter, view, or manipulate an internal anatomy of the patient <NUM>. In an embodiment, the surgical tool <NUM> is a grasper that can grasp tissue of the patient. The surgical tool <NUM> may be controlled manually, by a bedside operator <NUM>; or it may be controlled robotically, via actuated movement of the surgical robotic arm <NUM> to which it is attached. The robotic arms <NUM> are shown as a table-mounted system, but in other configurations the arms <NUM> may be mounted in a cart, ceiling or sidewall, or in another suitable structural support.

Generally, a remote operator <NUM>, such as a surgeon or other operator, may use the user console <NUM> to remotely manipulate the arms <NUM> and/or the attached surgical tools <NUM>, e.g., teleoperation. The user console <NUM> may be located in the same operating room as the rest of the system <NUM>, as shown in <FIG>. In other environments however, the user console <NUM> may be located in an adjacent or nearby room, or it may be at a remote location, e.g., in a different building, city, or country. The user console <NUM> may comprise a seat <NUM>, foot-operated controls <NUM>, one or more handheld user input devices, UID <NUM>, and at least one user display <NUM> that is configured to display, for example, a view of the surgical site inside the patient <NUM>. In the example user console <NUM>, the remote operator <NUM> is sitting in the seat <NUM> and viewing the user display <NUM> while manipulating a foot-operated control <NUM> and a handheld UID <NUM> in order to remotely control the arms <NUM> and the surgical tools <NUM> (that are mounted on the distal ends of the arms <NUM>.

In some variations, the bedside operator <NUM> may also operate the system <NUM> in an "over the bed" mode, in which the beside operator <NUM> (user) is now at a side of the patient <NUM> and is simultaneously manipulating a robotically-driven tool (end effector as attached to the arm <NUM>), e.g., with a handheld UID <NUM> held in one hand, and a manual laparoscopic tool. For example, the bedside operator's left hand may be manipulating the handheld UID to control a robotic component, while the bedside operator's right hand may be manipulating a manual laparoscopic tool. Thus, in these variations, the bedside operator <NUM> may perform both robotic-assisted minimally invasive surgery and manual laparoscopic surgery on the patient <NUM>.

During an example procedure (surgery), the patient <NUM> is prepped and draped in a sterile fashion to achieve anesthesia. Initial access to the surgical site may be performed manually while the arms of the robotic system <NUM> are in a stowed configuration or withdrawn configuration (to facilitate access to the surgical site. ) Once access is completed, initial positioning or preparation of the robotic system <NUM> including its arms <NUM> may be performed. Next, the surgery proceeds with the remote operator <NUM> at the user console <NUM> utilizing the foot-operated controls <NUM> and the UIDs <NUM> to manipulate the various end effectors and perhaps an imaging system, to perform the surgery. Manual assistance may also be provided at the procedure bed or table, by sterile-gowned bedside personnel, e.g., the bedside operator <NUM> who may perform tasks such as retracting tissues, performing manual repositioning, and tool exchange upon one or more of the robotic arms <NUM>. Non-sterile personnel may also be present to assist the remote operator <NUM> at the user console <NUM>. When the procedure or surgery is completed, the system <NUM> and the user console <NUM> may be configured or set in a state to facilitate post-operative procedures such as cleaning or sterilization and healthcare record entry or printout via the user console <NUM>.

In one embodiment, the remote operator <NUM> holds and moves the UID <NUM> to provide an input command to move a robot arm actuator <NUM> in the robotic system <NUM>. The UID <NUM> may be communicatively coupled to the rest of the robotic system <NUM>, e.g., via a console computer system <NUM>. The UID <NUM> can generate spatial state signals corresponding to movement of the UID <NUM>, e.g. position and orientation of the handheld housing of the UID, and the spatial state signals may be input signals to control a motion of the robot arm actuator <NUM>. The robotic system <NUM> may use control signals derived from the spatial state signals, to control proportional motion of the actuator <NUM>. In one embodiment, a console processor of the console computer system <NUM> receives the spatial state signals and generates the corresponding control signals. Based on these control signals, which control how the actuator <NUM> is energized to move a segment or link of the arm <NUM>, the movement of a corresponding surgical tool that is attached to the arm may mimic the movement of the UID <NUM>. Similarly, interaction between the remote operator <NUM> and the UID <NUM> can generate for example a grip control signal that causes a jaw of a grasper of the surgical tool <NUM> to close and grip the tissue of patient <NUM>.

The surgical robotic system <NUM> may include several UIDs <NUM>, where respective control signals are generated for each UID that control the actuators and the surgical tool (end effector) of a respective arm <NUM>. For example, the remote operator <NUM> may move a first UID <NUM> to control the motion of an actuator <NUM> that is in a left robotic arm, where the actuator responds by moving linkages, gears, etc., in that arm <NUM>. Similarly, movement of a second UID <NUM> by the remote operator <NUM> controls the motion of another actuator <NUM>, which in turn moves other linkages, gears, etc., of the robotic system <NUM>. The robotic system <NUM> may include a right arm <NUM> that is secured to the bed or table to the right side of the patient, and a left arm <NUM> that is at the left side of the patient. An actuator <NUM> may include one or more motors that are controlled so that they drive the rotation of a joint of the arm <NUM>, to for example change, relative to the patient, an orientation of an endoscope or a grasper of the surgical tool <NUM> that is attached to that arm. Motion of several actuators <NUM> in the same arm <NUM> can be controlled by the spatial state signals generated from a particular UID <NUM>. The UIDs <NUM> can also control motion of respective surgical tool graspers. For example, each UID <NUM> can generate a respective grip signal to control motion of an actuator, e.g., a linear actuator, that opens or closes jaws of the grasper at a distal end of surgical tool <NUM> to grip tissue within patient <NUM>.

In some aspects, the communication between the platform <NUM> and the user console <NUM> may be through a control tower <NUM>, which may translate user commands that are received from the user console <NUM> (and more particularly from the console computer system <NUM>) into robotic control commands that transmitted to the arms <NUM> on the robotic platform <NUM>. The control tower <NUM> may also transmit status and feedback from the platform <NUM> back to the user console <NUM>. The communication connections between the robotic platform <NUM>, the user console <NUM>, and the control tower <NUM> may be via wired and/or wireless links, using any suitable ones of a variety of data communication protocols. Any wired connections may be optionally built into the floor and/or walls or ceiling of the operating room. The robotic system <NUM> may provide video output to one or more displays, including displays within the operating room as well as remote displays that are accessible via the Internet or other networks. The video output or feed may also be encrypted to ensure privacy and all or portions of the video output may be saved to a server or electronic healthcare record system.

A surgical robotic apparatus that has a wireless power supply interface is now described. Referring to <FIG>, an example of a robotic surgical arm <NUM> is shown that is supported by a wheeled cart <NUM> and is ready to be coupled to the surgical robotic platform <NUM> for use during surgery upon the patient <NUM>. Here, a human patient is shown as an example, lying flat on the upper face of a surgical tabletop <NUM>. In this example, the surgical robotic platform <NUM> includes a surgical table <NUM> composed of the tabletop <NUM> on which the patient is lying on, and a table support <NUM> such as a pedestal that has raised the tabletop <NUM> above a floor and is stabilized by a table base <NUM> that is on the floor. The table support <NUM> may allow the tabletop <NUM> to have adjustable height, pitch, yaw or roll so as to enable a user such as a surgeon or assistant surgeon or nurse to perform a surgical procedure upon the patient <NUM> at a desired orientation or position. The table support <NUM> may also enable the tabletop <NUM> to be adjustable horizontally, either in a length direction of the tabletop or in a width direction.

The robotic arm <NUM> has a proximal end portion <NUM> and a distal end portion <NUM>, between which are two or more (in the example shown here, three) arm joints <NUM>. Each joint <NUM> is coupled to an adjacent pair of linkages. In the example shown, the arm <NUM> has three linkages but in general there may be more. The joints are motorized to enable precise and dexterous positioning of the distal end portion <NUM> to which a surgical tool <NUM> is attached, so that the distal end of the tool <NUM> can be precisely positioned inside the patient <NUM> during surgery. The linkage at the distal end portion <NUM> is configured to receive any one of several types of surgical tools <NUM> (not shown) such as any one of those mentioned earlier in connection with <FIG>.

The robotic surgical arm <NUM> also has its proximal end portion <NUM> that is configured, by virtue of its coupling member <NUM>, to be coupled to an adapter <NUM> of the surgical robotic platform <NUM>, for use during a particular surgery session at the platform <NUM>. In the example shown, the adapter <NUM> is secured to a surgical table <NUM>. In other surgical platforms <NUM> however, the adapter <NUM> may be attached to for example a cart, a ceiling, a sidewall, or even another suitable support structure.

There may be several adapters <NUM> coupled to (or part of) the surgical robotic platform <NUM>, where each is to receive a respective arm <NUM>, but in the interest of conciseness <FIG> shows only one coupled to the surgical table <NUM>. Each adapter <NUM> has a mechanical latching mechanism that latches the coupling member <NUM> of the arm <NUM> to the adapter <NUM>, in a secure but detachable and re-attachable manner. The latching mechanism may be manually (human user) actuated by a lever or other hand-operated feature, or it may be motorized and automatically controlled to latch itself once the coupling member <NUM> of the arm <NUM> has been placed into position in a complementary part of the latching mechanism, as seen in <FIG> for example. The adapter <NUM> may be a rigid structural support member that mechanically engages with the coupling member <NUM> at the proximal end portion <NUM> of the arm <NUM>, so as to securely affix the proximal end portion of the arm <NUM> to the robotic platform <NUM> in what is referred to here as its coupled state (during the surgical operation. ) In the example shown, the adapter <NUM> is anchored to the tabletop support <NUM>, and extends laterally or horizontally outward from the tabletop support <NUM>. The adapter <NUM> may be affixed to the tabletop support <NUM> so as to move as one with the former, as the position and orientation of the tabletop <NUM> is adjusted. Alternatively, the adapter <NUM> may be affixed directly to the bottom or side of the tabletop <NUM>, or directly to the floor through a separate support member (that is separate from the tabletop support <NUM> and that may also be adjustable in position (height) or orientation.

In the robotic surgery arm <NUM>, the coupling member <NUM> is designed so that it can be de-coupled from the adapter <NUM> once the surgery session has ended, so that the arm <NUM> can then be stored (e.g., on the cart <NUM>), until the arm <NUM> is to be re-coupled to the adapter <NUM> for use during another surgical session at the platform. To illustrate this, <FIG> shows how the height of a support member <NUM> of the cart <NUM> has been adjusted so that a mouth of the coupling member <NUM> is brought to the same height as the adapter <NUM>. Next, the cart <NUM> is wheeled towards the surgical table <NUM> until the mouth of the coupling member <NUM> engages the outside end of the adapter <NUM>, and is then locked into that coupled position by the latching mechanism - see <FIG>. The cart <NUM> is then wheeled away from the surgical table <NUM> thereby leaving behind the coupled arm <NUM>, as seen in <FIG>. The arm <NUM> is now ready for use in the surgical operation. This procedure may be repeated to bring a total of two, three or more arms into their coupled states at the surgical table <NUM>, where each arm is locked into a fixed position at its respective adapter <NUM>.

It should be noted that while the figures illustrate the example where the coupling member <NUM> of the arm <NUM> is a receptacle that receives and holds a "male" outside end of the adapter <NUM>, an alternative is that the outside end of the adapter <NUM> is configured as a receptacle that receives and holds a male coupling member <NUM>.

In another embodiment of the invention, the adapter <NUM> can pivot around a pivot joint (not shown), such that once the arm <NUM> is in its coupled state, it too will pivot about the pivot joint. The mechanical latching mechanism in that case may latch the coupling member <NUM> of the arm <NUM> to a complementary part of the adapter <NUM> that also pivots. The pivot axis may, for example, be a vertical axis. The mechanical latching mechanism for this embodiment may also be configured to detach and re-attach the arm <NUM>, by for example being manually (human user) actuated by a lever or other hand-operated feature, or it may be motorized and automatically controlled to latch itself once the proximal end of the arm has been placed into position (at a complementary part of the latching mechanism that is on the pivot joint.

Still referring to <FIG>, these figures also illustrate how wireless power transfer can be achieved, from the surgical robotic platform <NUM> to the electrical load in the arm <NUM>, using a resonant mode transformer coupled power converter. The power converter may have a primary side <NUM> at the surgical platform <NUM>, e.g., attached to the surgical table <NUM> as shown, that is coupled via mutual inductance to a secondary side <NUM> that is in the arm <NUM>. The primary side <NUM> feeds power to a transformer primary part <NUM> that is in the adapter <NUM>, while a transformer secondary part <NUM> that is in the arm <NUM> receives that power and feeds it to the secondary side <NUM>. Examples of the transformer primary and secondary parts are shown in <FIG> and in <FIG> to be discussed below. More generally, the transformer primary part <NUM> has a transformer primary coil or multi-turn winding that may be housed in the adapter <NUM>, and the transformer secondary part <NUM> has a transformer secondary coil or multi-turn winding that may be housed in the proximal end portion <NUM> of the arm, and more specifically in the coupling member <NUM>. The primary and secondary coils, or the primary part <NUM> and the secondary part <NUM>, may be rigidly held at fixed positions and orientations relative to each other (once the arm <NUM> is coupled to the adapter <NUM> as seen for example in <FIG> and in <FIG>) that enable mutual inductive coupling between them for operation of the power converter.

As mentioned above, the electrical load in the arm <NUM> is powered by the output of the secondary side <NUM> of the power converter. The load may include a communications interface (communications circuity), arm joint motor driver and control circuitry including arm joint brake driver and control circuity (e.g., including brushless dc motor controllers), digital camera electronics, and energy emitter driver circuitry. The communications interface may be, for example, a serial peripheral interface bus, SPI, or other reliable digital communications interface that can deliver the arm linkage joint control and tool control signals from a computer system at the surgical platform <NUM>, e.g., the control tower <NUM>. The control tower <NUM> may have translated user commands received from the surgical console <NUM> (signals that are sensing the orientation or position of a handheld controller) and robotic feedback signals from the arm, into robotic commands, which may be the arm linkage joint control signals in the arm's joint space, and one or more tool control signals for the arm.

The arm joint motor driver and control circuitry drives or energizes several actuators (at multiple joints) in accordance with several arm linkage joint control signals that are received from the robotic surgical platform <NUM> (e.g., from the control tower <NUM> - see <FIG>), by the communications interface. The digital camera electronics forms part of a digital camera in the surgical tool <NUM>, e.g., an endoscopic camera. The energy emitter driver circuitry serves to energize one or more energy emitters that are in the surgical tool <NUM>, such as a coagulation laser or an ultrasonic emitter. In one embodiment, the actuator control signals as well as any other control signals that are not part of the wireless electrical power delivery interface to the arm <NUM> (which may include a resonant mode transformer coupled power converter as described above) are received and transmitted by the communications interface through a communications cable that may run from the arm <NUM> to the robotic surgical platform <NUM>, e.g., to the surgical table <NUM> and then to the control tower <NUM>.

<FIG> shows a circuit schematic of an example of the resonant mode transformer coupled power converter. The primary side <NUM> of the power converter has a group of solid state switches (depicted in the example here as metal oxide semiconductor field effect transistors) that route power from a dc voltage rail at Vin(dc). The primary side <NUM> be housed in the adapter <NUM> as shown in <FIG>, but it could alternatively be housed in the tabletop support <NUM>, in the base <NUM>, or elsewhere on the surgical table <NUM> or even in another element of the robotic surgical platform <NUM>. The dc voltage rail at Vin(dc) may be produced by a platform power supply (not shown), such as an ac-dc power converter that converts 120Vac/240Vac "wall power" that may be available in the operating room, to a suitable dc voltage. The platform power supply supplies the power that is drawn by the resonant mode power converter, which is in turn supplying the power that is drawn by the electrical load in the coupled arm <NUM>. In other words, the output Vout(dc) of the resonant mode power converter is a power supply to the communications interface circuitry and the arm joint and tool driver circuitry in the arm <NUM>, as described above. Just as an example, Vout(dc) may be 48Vdc at <NUM> Watts.

The switches in the primary side <NUM> route power from Vin(dc) to feed a transformer primary coil Lp. The latter is part of a primary side resonant circuit, which is formed together with a capacitor Cp in the primary side <NUM>. The switches are turned on and turned off under control of a switch mode power supply resonant controller also in the primary side <NUM>, e.g., a transformer driver that drives the primary side resonant circuit with a <NUM>% duty cycle square wave having a controlled working (switching) frequency, in order to transfer power to the secondary side <NUM> in a controlled, efficient manner, as needed by the electrical load in the arm <NUM> that is coupled to the output of the secondary side <NUM> at Vout(dc). The secondary side <NUM> has a transformer secondary coil Ls, which is part of a secondary side resonant circuit along with capacitor Cs. There is mutual inductive coupling of magnetic flux across a non-conductive (electrically insulating) gap <NUM> between the coils, from the transformer primary part <NUM> to the transformer secondary part <NUM>. This enables switch mode power transfer from the primary side <NUM> to the secondary side <NUM>. The power required by the load may be met by changing the switching frequency of the control signal of the resonant controller in the primary side <NUM>, e.g., by matching the switching frequency with the resonance frequency of the L-C based resonant circuit in the primary side in order to increase power transfer. The closer the switching frequency to the resonant frequency (fr) of Lp and Cp, the higher the voltage at the secondary side <NUM>. When Vout is lower than the setting voltage, which may be for example 48V, the feedback signals make the controller switching frequency closer to the resonant frequency (fr) to make Vout higher. When Vout great than the setting voltage, the feedback signal can force the switching frequency away from fr to make Vout lower. The feedback signal is an analog signal, e.g., Vfb, and as explained below may be converted into a PWM waveform before being passed over an optical interface over the gap, or alternatively by the communication interface circuitry mentioned above. Note that the turns ratio of the primary coil to the secondary coil need not be <NUM>:<NUM>.

The ac (switched) voltage at the output of the resonant circuit Ls-Cs is converted into dc by a rectifier (in this example, a full wave rectifier composed of the four diodes as shown) and then filtered by a filter capacitor Cf, resulting in the output voltage Vout(dc). If regulation of Vout(dc) is desired, then this may be achieved by configuring the resonant controller to vary the switching frequency of its control of the switches, in a feedback controlled manner. This would be in response to a feedback voltage Vfb that represents an error or difference between a reference voltage Vref and the power converter output voltage Vout(dc). The feedback voltage Vfb may be provided to the resonant controller, not in its original form but rather in the form of Vfb', where Vfb is converted in the secondary side <NUM> into a PWM signal, before it is then transmitted by an optical transmitter <NUM> of an optical coupler to an optical receiver <NUM> in the primary side <NUM>, where it is then converted back into analog form as Vfb' before being used by the resonant controller. The technique of converting the feedback signal into digital form (e.g., as a PWM signal) for its transfer from the arm <NUM> to the robotic surgical platform <NUM> increases immunity to noise during the transfer. Other techniques for delivering the feedback voltage Vfb from the secondary side <NUM> to the primary side <NUM> in a wireless or contact-less manner across the electrically insulating gap <NUM> include the use of an auxiliary transformer. In yet another embodiment, the feedback voltage Vfb' is received in the primary side <NUM> via a cabled communications interface with the secondary side <NUM> in the arm <NUM>, e.g., the same SPI that is used by the communications interface in the arm <NUM> for receiving the robotic commands from the control tower <NUM>.

<FIG> and <FIG> are perspective views of the two parts of an example multi-part transformer, that may be used in the resonant mode transformer coupled power converter of <FIG>. The transformer primary part <NUM>, which is in the proximal coupling member <NUM> of the arm <NUM> (see <FIG>), and has a primary coil that terminates in a pair of primary terminals <NUM>. There is also the transformer secondary part <NUM>, which is in the adapter <NUM> and has a secondary coil that terminates in a pair of secondary terminals <NUM>. <FIG> shows the transformer in its uncoupled state, when the arm <NUM> has been de-coupled from the adapter <NUM> for purposes of storage - see <FIG>: the primary part <NUM> is spaced so far apart from the secondary part <NUM> that there is insufficient mutual inductive coupling between them (to transfer enough power to supply the electrical load in the arm <NUM>. ) In contrast, <FIG> shows the transformer in its coupled state, when the arm <NUM> is coupled to the adapter <NUM> - see <FIG>. There, the primary part <NUM> has been brought close enough to the secondary part <NUM> such that the two are separated only by the gap <NUM> - see <FIG>. This state allows sufficient power to be transferred from the primary to the secondary (so as to supply the electrical load in the arm <NUM>.

In the particular example of <FIG> and <FIG>, the multi-part transformer may have a core form or a shell form in which each of the primary coil and the secondary coil is wound around a respective, magnetic or ferromagnetic core or shell portion that may be composed of laminated steel (steel sheets lying in the x-y plane and stacked in the z-direction. ) As seen in the figures, in each of the primary part <NUM> and the secondary part <NUM> of the transformer, there is a pair of support plates that support the coil of that part, one on the left side and another on the right side of the coil. The four support plates are all parallel to each other, and the two inner ones may be separated by less than <NUM> once the arm <NUM> has been coupled to the adapter <NUM> (resulting in the coupled state shown in <FIG>. ) For each of the primary part <NUM> and the secondary part <NUM> of the transformer, the core form or shell form part may be composed of magnetic or ferromagnetic material such as laminated steel.

The transformer primary part <NUM>, including the primary coil, may be entirely encapsulated by insulating material, as is the secondary part <NUM>. This may ensure that the coils are not exposed to touch, which is particularly desired when the coils support peak to peak voltages that are greater than <NUM> Vac. The encapsulation material may be selected to have sufficient magnetic permeability, e.g., containing ferrite particles, and it may fill the entire gap <NUM> as seen in <FIG>, where the flat outside face of the encapsulated primary part <NUM> will abut the flat outside face of the encapsulated secondary part <NUM> (so as to enable efficient mutual inductive coupling between the primary coil and the secondary coil at the switching frequency of the power converter.

As seen in the figures, each part of the multi-part transformer may have a flat face that becomes aligned with, and is held at a fixed distance from, the other part of the multi-part transformer, when the arm <NUM> has been coupled to the adapter <NUM>. Note that perfect alignment in the x, y and z-axes that are shown is not necessary during working or operation of the arm <NUM>. However, misalignment in any of the axes may result in a reduction in efficiency of the power transfer. In one embodiment, once the arm <NUM> is coupled to the adapter <NUM>, there may be an electrically insulating gap <NUM> of no more than <NUM> between the primary coil and the secondary coil, which may ensure sufficient mutual inductive coupling to deliver at Vout(dc), 200W at 48V. In one embodiment, the flat outside faces of the encapsulated primary and second parts abut each other, while maintaining the gap <NUM> between the primary and secondary coils.

In the example of <FIG>, the primary and secondary coils are positioned such that the mutual inductive coupling (magnetic flux) between them is through the lateral or side faces of their respective "housings", which are the adapter <NUM> and the coupling member <NUM>, respectively. They could however be positioned differently. For example, the primary and secondary coils could be positioned such that the mutual inductive coupling is through the top face of the adapter <NUM> and the inner top face of the coupling member <NUM>, at the interface or boundary between the two housings. In another example, the primary and secondary coils could be positioned so that the mutual inductive coupling is through the bottom face of the adapter <NUM> and the inner bottom face of the coupling member <NUM>.

In the example of <FIG>, the lateral or side faces of the two housings of the adapter <NUM> and the coupling member <NUM> define a vertical interface or boundary, through which the magnetic flux lines of the mutual inductive coupling pass from one housing to the other. This suggests that the primary and secondary coils could have the same orientation, e.g., the length axes of both may be vertical, as seen in <FIG>. But their orientation may be different such that the interface or boundary between them need not be vertical. For example, the two coils could be tilted in the same direction, such that the magnetic flux lines of their mutual inductive coupling cuts through a diagonal boundary line (rather than a vertical boundary as seen in <FIG>. ) In other words, the primary and secondary coils may be oriented differently than shown in <FIG> and in <FIG>, so that the magnetic flux lines of their mutual inductive coupling cross an interface boundary that is not vertical.

Claim 1:
A surgical robotic apparatus comprising:
a surgical robotic arm (<NUM>) having a proximal end portion (<NUM>) and a distal end portion (<NUM>), where the distal end portion is configured to receive a surgical tool (<NUM>), and the proximal end portion is configured to be removably coupled to a surgical robotic platform (<NUM>) for surgery and decoupled from the platform for storage;
characterised by
a secondary side (<NUM>) of a resonant-mode transformer-coupled power converter that also has a primary side (<NUM>),
wherein the secondary side of the power converter has a transformer secondary coil (<NUM>) in the proximal end portion of the arm, and wherein the primary side has a transformer primary coil (<NUM>) in the platform, and wherein the primary and secondary coils are held at positions and orientations that enable mutual inductive coupling between them for operation of the power converter when the arm is coupled to the platform for wireless power transfer through the transformer primary and secondary coils.