System and method for collision detection using sensed joint movement

Abstract

A computer-assisted system includes a robotic manipulation system and a control system. The robotic manipulation system includes a manipulator arm including a non-driven joint, including a joint sensor configured to sense joint movement of the non-driven joint, and a brake that applies a braking force to the non-driven joint. The control system is configured to modulate the braking force of the brake based on a current usage situation of the computer-assisted system such that a force or torque at the non-driven joint causes a movement of the non-driven joint, the force or torque being caused by a collision of the manipulator arm distal to the non-driven joint and exceeding a force or torque threshold set based on the current usage situation, and determine whether a collision has occurred based on whether the movement of the non-driven joint is detected by the joint sensor.

Description

SYSTEM AND METHOD FOR COLLISION DETECTION USING SENSED JOINT MOVEMENTCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to and the benefit of the filing date of U.S. Provisional Patent Application 63 / 542,974 filed on October 6, 2023, which is hereby incorporated by reference herein in its entirety.BACKGROUNDField of Invention

[0002] The present invention generally provides improved computer-assisted devices, systems, and methods.Overview

[0003] Computer-assisted systems can be used to perform a task at a worksite. For example, a computer-assisted system may comprise a handheld, motorized tool assembly. As another example, a computer-assisted system may comprise a drivable cart that itself may include one or more manipulators arms to manipulate instruments for performing the task.

[0004] Example computer-assisted systems include industrial and recreational robotic systems. Example computer-assisted systems also include medical robotic systems used in procedures for diagnosis, non-surgical treatment, surgical treatment, etc.

[0005] Some computer-assisted systems include one or more instruments that are articulated in order to perform various procedures. The computer-assisted system can be automated, semi- automated, teleoperated, etc. In a teleoperated example, a human operator manipulates one or more leader input controls to command motion of one or more follower instruments located in a workspace. In some examples, the teleoperated system is configured to support an instrument that includes an imaging device, such as an endoscope or a camera, that enables the operator to observe the workspace. In some instances, the field of view of the imaging device is directed to enable the operator to see the instrument(s) as the operator commands motion of the instrument(s).

[0006] In instances of computer-assisted systems comprising a drivable cart, the drivable cart may be transported or moved across a floor (e.g., within a room, between rooms, etc.). Movement of the drivable cart may result in the drivable cart, or one or more manipulator arms connected to the drivable cart, to collide with a generic object (e.g., wall,table, etc.) or a person. Accordingly, quick collision detection with high sensitivity (z.e., able to detect a collision with only a small force interaction between colliding items) may be desirable and beneficial.SUMMARY

[0007] In general, in one aspect, one or more embodiments relate to a computer- assisted system comprising: a robotic manipulation system with a manipulator arm comprising: a non-driven joint, comprising: a joint sensor configured to sense joint movement of the non-driven joint, and a brake that applies a braking force to the non-driven joint; and a control system configured to: modulate the braking force of the brake based on a current usage situation of the computer-assisted system such that a force or torque at the nondriven joint causes a movement of the non-driven joint, the force or torque being caused by a collision of the manipulator arm distal to the non-driven joint and exceeding a force or torque threshold set based on the current usage situation; and determine whether a collision has occurred based on whether the movement of the non-driven joint is detected by the joint sensor.

[0008] In general, in one aspect, one or more embodiments relate to a method for collision detection in a computer-assisted system using sensed joint movement of a robotic manipulation system with a manipulator arm comprising: a non-driven joint, comprising: a joint sensor configured to sense joint movement of the non-driven joint, and a brake that applies a braking force to the non-driven joint, and wherein the method comprises: modulating the braking force of the brake based on a current usage situation of the computer- assisted system such that a force or torque at the non-driven joint causes a movement of the non-driven joint, the force or torque being caused by a collision of the manipulator arm distal to the non-driven joint and exceeding a force or torque threshold set based on the current usage situation; and determining whether a collision has occurred based on whether the movement of the non-driven joint is detected by the joint sensor.

[0009] In general, in one aspect, one or more embodiments relate to a non-transitory machine-readable medium comprising a plurality of machine-readable instructions executed by one or more processors associated with a computer-assisted system, the plurality of machine-readable instructions causing the one or more processors to perform a method for collision detection using sensed joint movement of a robotic manipulation system with a manipulator arm comprising: a non-driven joint, comprising: a joint sensor configured to sense joint movement of the non-driven joint, and a brake that applies a braking force to thenon-driven joint, and wherein the method comprises: modulating the braking force of the brake based on a current usage situation of the computer-assisted system such that a force or torque at the non-driven joint causes a movement of the non-driven joint, the force or torque being caused by a collision of the manipulator arm distal to the non-driven joint and exceeding a force or torque threshold set based on the current usage situation; and determining whether a collision has occurred based on whether the movement of the nondriven joint is detected by the joint sensor.

[0010] Other aspects of the invention will be apparent from the following description and the appended claims.BRIEF DESCRIPTION OF DRAWINGS

[0011] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component that is illustrated in various figures may be represented by a like numeral. For purposes of clarity, not every component may be labeled in every drawing. In the drawings:

[0012] FIG. 1 depicts a computer-assisted system in accordance with one or more embodiments.

[0013] FIG. 2 depicts a drivable cart in accordance with one or more embodiments.

[0014] FIG. 3 depicts a primary control interface for a drivable cart in accordance with one or more embodiments.

[0015] FIG. 4A depicts a manipulator arm in accordance with one or more embodiments.

[0016] FIG. 4B depicts a simplified schematic of a manipulator arm in accordance with one or more embodiments.

[0017] FIG. 5 depicts a spring actuated electromagnetic brake system in accordance with one or more embodiments.

[0018] FIG. 6 depicts a floor plan of medical facility in accordance with one or more embodiments.

[0019] FIG. 7 depicts an operation room containing a computer-assisted system in a second usage situation in accordance with one or more embodiments.

[0020] FIG. 8 depicts an operation room containing a computer-assisted system in a third usage situation in accordance with one or more embodiments.

[0021] FIG. 9A depicts an example applied force plot in accordance with one or more embodiments.

[0022] FIG. 9B depicts an example relative joint movement plot in accordance with one or more embodiments.

[0023] FIG. 10 depicts a flowchart in accordance with one or more embodiments.DETAILED DESCRIPTION

[0024] In the following description, specific details are set forth describing some embodiments consistent with the present disclosure. Numerous specific details are set forth in order to provide a thorough understanding of the embodiments. It will be apparent, however, to one skilled in the art that some embodiments can be practiced without some or all of these specific details. The specific embodiments disclosed herein are meant to be illustrative but not limiting. One skilled in the art may realize other elements that, although not specifically described here, are within the scope and the spirit of this disclosure. In addition, to avoid unnecessary repetition, one or more features shown and described in association with one embodiment may be incorporated into other embodiments unless specifically described otherwise or if the one or more features would make an embodiment non-functional.

[0025] In some instances, well known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the embodiments. For example, devices and substitutes that provide or enable linear actuation, such as pneumatic cylinders and lead screws are well understood without detailed descriptions of aspects of such devices like gaskets, thread pitch, etc. Thus, specific descriptions regarding such devices, procedures, components, and how circuits can be integrated with, or used within, embodiments of the instant disclosure are omitted herein for concision where applicable without causing undue ambiguity or uncertainty.

[0026] Throughout the application, ordinal numbers (e.g., first, second, third, etc.) may be used as an adjective for an element (i.e., any noun in the application). The use of ordinal numbers is not to imply or create any particular ordering of the elements nor to limit any element to being only a single element unless expressly disclosed, such as using the terms “before,” “after,” “single,” and other such terminology. Rather, the use of ordinal numbers is to distinguish between the elements. By way of an example, a first element is distinct from a second element, and the first element can encompass more than one element and succeed (or precede) the second element in an ordering of elements.

[0027] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0028] Terms such as “approximately,” “substantially,” etc., mean that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0029] In the following description of Figs. 1-10, any component described with regard to a figure, in various embodiments disclosed herein, may be equivalent to one or more like-named components described with regard to any other figure. For brevity, descriptions of these components are not necessarily repeated with regard to each figure. Thus, each and every embodiment of the components of each figure is incorporated by reference and assumed to be optionally present within every other figure having one or more like-named components. Additionally, in accordance with various embodiments disclosed herein, any description of the components of a figure is to be interpreted as an optional embodiment which may be implemented in addition to, in conjunction with, or in place of the embodiments described with regard to a corresponding like-named component in any other figure.

[0030] Considering the figures, specific non-limiting embodiments are described in further detail. It should be understood that the various systems, components, features, and methods described relative to these embodiments can be used either individually and / or in any desired combination as the disclosure is not limited to only the specific embodiments described herein.

[0031] This disclosure describes various devices, elements, and portions of computer- assisted systems and elements in terms of their state in three-dimensional space. As used herein, the term “position” refers to the location of an element or a portion of an element (e.g., three degrees of translational freedom in a three-dimensional space, such as along Cartesian x-, y-, and z-coordinates). As used herein, the term “orientation” refers to the rotational placement of an element or a portion of an element (e.g., three degrees of rotational freedom in three-dimensional space, such as about roll, pitch, and yaw axes, represented in angle-axis, rotation matrix, quaternion representation, and / or the like). As used herein, and for a device with a kinematic series, such as with a repositionable structure with a plurality of links coupled by one or more joints, the term “proximal” refers to a direction toward a base of the kinematic series, and “distal” refers to a direction away from the base along the kinematic series.

[0032] As used herein, the term “pose” refers to the multi-degree of freedom (DOF) spatial position and orientation of a coordinate system of interest attached to a rigid body. In general, a pose includes a pose variable for each of the DOFs in the pose. For example, a full 6-DOF pose for a rigid body in three-dimensional space would include 6 pose variables corresponding to the 3 positional DOFs (e.g., x, y, and z) and the 3 orientational DOFs (e.g., roll, pitch, and yaw). A 3-DOF position only pose would include only pose variables for the 3 positional DOFs. Similarly, a 3-DOF orientation only pose would include only pose variables for the 3 rotational DOFs. Further, a velocity of the pose captures the change in pose over time (e.g., a first derivative of the pose). For a full 6-DOF pose of a rigid body in three-dimensional space, the velocity would include 3 translational velocities and 3 rotational velocities. Poses with other numbers of DOFs would have a corresponding number of velocities translational and / or rotational velocities.

[0033] Aspects of this disclosure are described in reference to computer-assisted systems, which can include devices that are teleoperated, externally manipulated, autonomous, semiautonomous, and / or the like. Further, aspects of this disclosure are described in terms of an implementation using a teleoperated surgical system, such as the da Vinci® Surgical System commercialized by Intuitive Surgical, Inc. of Sunnyvale, California. Knowledgeable persons will understand, however, that inventive aspects disclosed herein may be embodied and implemented in various ways, including teleoperated and nonteleoperated, and medical and non-medical embodiments and implementations. Implementations on da Vinci® Surgical Systems are merely exemplary and are not to be considered as limiting the scope of the inventive aspects disclosed herein. For example, techniques described with reference to surgical instruments and surgical methods may be used in other contexts. Thus, the instruments, systems, and methods described herein may be used for humans, animals, portions of human or animal anatomy, industrial systems, general robotic, or teleoperated systems. As further examples, the instruments, systems, and methods described herein may be used for non-medical purposes including industrial uses, general robotic uses, sensing or manipulating non-tissue work pieces, cosmetic improvements, imaging of human or animal anatomy, gathering data from human or animal anatomy, setting up or taking down systems, training medical or non-medical personnel, and / or the like. Additional example applications include use for procedures on tissue removed from human or animal anatomies (with or without return to a human or animal anatomy) and for procedures on human or animal cadavers. Further, these techniques can also be used for medical treatment or diagnosis procedures that include, or do not include, surgical aspects.

[0034] Specific embodiments of the disclosure will now be described in detail with reference to the accompanying figures. Like elements in the various figures are denoted by like reference numerals for consistency.

[0035] FIG. 1 depicts an example computer-assisted system that can be used for medical procedures (e.g., surgical procedures). As such, the example computer-assisted system (100) of FIG. 1 is herein also referred to as a computer-assisted medical system (100) (or, more simply, “medical system (100)”). As depicted, the computer-assisted system (100) may include a robotic manipulation system (102), a user control system (104), and an auxiliary system (106). The robotic manipulation system (102), user control system (104), and auxiliary system (106) may be, at least, communicatively coupled to one another using wireless or wired connections (117) or a combination of wireless and wired connections.

[0036] The computer-assisted system (100) can be used by one or more users working in conjunction to perform a computer-assisted procedure, e.g., a medical procedure. For example, the computer-assisted system (100) may be used to perform a computer-assisted medical diagnostic or therapeutic medical procedure on a patient (108) on an operating table (119). In the depiction of FIG. 1, the one or more users include a first clinician (101) (e.g., a surgeon), an assistant (103), a nurse, (105), and a second clinician (e.g., an anesthesiologist)(107). It is emphasized that the one or more users depicted in FIG. 1 are provided solely as an example. In general, additional, fewer, or alternative team members may be present during a medical procedure. As such, the listed users should not impose a limitation on the instant disclosure.

[0037] In accordance with one or more embodiments, the robotic manipulation system (102) can include a drivable cart (described below in reference to FIG. 2, not shown in FIG. 1), a primary control interface (111), a support column (described below in reference to FIG. 2, not shown in FIG. 1) that vertically extends from the drivable cart, a boom (113) extending from the support column, and at least one manipulator arm connected to the distal end of the boom (113). In the example of FIG. 1, the robotic manipulation system (102) is depicted with four manipulator arms, namely, a first manipulator arm (112), as second manipulator arm (114), a third manipulator arm (116), and a fourth manipulator arm (118). Each manipulator arm may support a removably coupled instrument (also called a tool). In the example of FIG. 1, the instrument may enter a workspace, such as the body of the patient(108), through an entry location (e.g., a natural orifice such as the throat or anus, or through an incision), while an operator (e.g., first clinician (101)) views the worksite with theinstrument (e.g., a surgical site in the surgical scenario) through the user control system (104).

[0038] An image of the worksite may be obtained by an imaging instrument including an imaging device (e.g., an endoscope, an optical camera, an ultrasonic probe, etc. in a medical example). The imaging instrument can be used for imaging the worksite, and may be manipulated by a manipulator arm (e.g., first manipulator arm (112)) of the robotic manipulation system (102) so as to position and orient the imaging instrument. The auxiliary system (106) may process the captured images in a variety of ways prior to any subsequent display on a display monitor (121). For example, the auxiliary system (106) may overlay the captured images with a virtual control interface prior to displaying the combined images to the operator (e.g., first clinician (101)) via the user control system (104) or other display systems located locally or remotely from the procedure. One or more separate displays (not shown in FIG. 1) may also be coupled with a computing system (e.g., a control system) and / or the auxiliary system (106) for local and / or remote display of images, such as images of the procedure site, or other related images.

[0039] The number of instruments used at one time generally depends on the task and space constraints, among other factors. If it is appropriate to change, clean, inspect, or reload one or more of the instruments being used during a procedure, an assistant (e.g., assistant (103)) may remove the instrument from the manipulator arm (e.g., first manipulator arm (112)), and replace it with the same instrument or another instrument.

[0040] The computer-assisted system (100) may include one or more control systems (142). A control system (142) may be used to process input provided by the user control system (104) from an operator (e.g., first clinician (101)). A control system (142) may further be used to provide an output, e.g., a video image for display. One or more control systems (142) may further be used to control aspects of the at least one manipulator arm, such as movement between kinematic configurations, braking or stopping of the at least one manipulator arm, and collision detection. In some instances, the control system (142) may be disposed within, or otherwise considered part of, the robotic manipulation system (102), the user control system (104), and / or the auxiliary system (106).

[0041] A control system (142) may include one or more computer processors, non- persistent storage (e.g., volatile memory, such as random access memory (RAM), cache memory), persistent storage (e.g., a hard disk, an optical drive such as a compact disk (CD) drive or digital versatile disk (DVD) drive, a flash memory, etc.), a communication interface(e.g., Bluetooth interface, infrared interface, network interface, optical interface, etc.), and numerous other elements and functionalities.

[0042] A computer processor of a control system (142) may be part or all of an integrated circuit for processing instructions. For example, the computer processor may be one or more cores or micro-cores of a processor. Control system(s) (142) may also communicate with one or more input devices, such as a touchscreen, keyboard, mouse, microphone, touchpad, electronic pen, or any other type of input device.

[0043] A communication interface of a control system (142) may include an integrated circuit for connecting the control system to a network (not shown) (e.g., a local area network (LAN), a wide area network (WAN) such as the Internet, mobile network, or any other type of network) and / or to another device, such as another control system (142).

[0044] Further, a control system (142) may communicate with one or more output devices, such as a display device (e.g., display monitor (121)). A display device may be a liquid crystal display (LCD), a plasma display, touchscreen, organic LED display (OLED), projector, or other display device. Output devices may include, but are not limited to, a printer, a speaker, external storage, or any other output device. One or more of the output devices may be the same or different from the input device(s). Many different types of control systems (142) exist, and the aforementioned input and output device(s) may take other forms.

[0045] Software instructions in the form of computer readable program code to perform embodiments of the disclosure may be stored, in whole or in part, temporarily or permanently, on a non-transitory computer readable medium such as a CD, DVD, storage device, a diskette, a tape, flash memory, physical memory, or any other computer readable storage medium. Specifically, the software instructions may correspond to computer readable program code that, when executed by a processor(s), is configured to perform one or more embodiments of the disclosure.

[0046] A control system (142) may be connected to or be a part of a network. The network may include multiple nodes. Each node may correspond to a control system, or a group of nodes. By way of an example, embodiments of the disclosure may be implemented on a node of a distributed system that is connected to other nodes. By way of another example, embodiments of the disclosure may be implemented on a distributed computing system having multiple nodes, where each portion of the disclosure may be located on a different node within the distributed computing system. Further, one or more elements of theaforementioned control system(s) (142) may be located at a remote location and connected to the other elements over a network.

[0047] FIG. 2 depicts an alternative viewpoint of the robotic manipulation system (102), in accordance with one or more embodiments. Specifically, the viewpoint of FIG. 2 depicts the drivable cart (202) and support column (204), in addition to some previously labelled components. The drivable cart (202) is configured to be moved across a floor (e.g., driven, by a motor, on a set of wheels). Movement of the drivable cart (202) results in the movement, or relocation, of the entire robotic manipulation system (102).

[0048] In one or more embodiments, the support column (204) may be raised or lowered (e.g., telescoping). Further, the boom (113) can be extended, retracted, pivoted, and so forth. The at least one manipulator arm (e.g., first manipulator arm (112)) is attached to the boom (113) and can be rotated relative to a first axis (206) such that the at least one manipulator arm can be “rotated out,” “brought in,” or otherwise manipulated according to a particular need or implementation. It will be understood that other movable components not explicitly illustrated herein may also be present on robotic manipulation system (102) or on other robotic manipulation system implementations.

[0049] FIG. 3 illustrates an example primary control interface (111). The primary control interface (111) may be used to control movement of the robotic manipulation system (102) (e.g., between two locations) on the drivable cart (202), control other aspects of the robotic manipulations system such as the position of the boom (113), and provide a touchscreen (310). In one or more embodiments, primary control interface (111) is implemented as a handlebar-based control interface integrated into robotic manipulation system (102) (i.e., built directly into the robotic manipulation system (102) such as on a side opposite to the extension of the boom (113)). FIG. 3 shows various controls that may be included in primary control interface (111). The primary control interface (111) includes a handlebar (301) with one or more drive switches. In the example of FIG. 3, two drive switches are shown, namely, a first drive switch (302) and a second drive switch (304). In general, depression of a drive switch drives the robotic manipulation system (102), where the use of two drive switches (as shown in FIG. 3) may allow an operator to steer or direct the drivable cart (202) of the robotic manipulation system (102) in a desired direction (e.g., forward, left, right, backward, etc.). In one or more embodiments, the one or more drive switches of the primary control interface (111) each include a pressure sensor (not shown) or position encoder (not shown) to determine (at least relatively) an applied force or displacement on the drive switch, respectively. Using the pressure sensor or positionencoder, the primary control interface (111) can alter the speed of the drivable cart (202), when moved, according to the sensed pressure or displacement. Typically, the greater the pressure or displacement applied to the one or more drive switches, the faster the movement of the drivable cart (202). In one or more embodiments, the speed of the drivable cart (202) is determined based on the sensed pressure of displacement of the one or more drive switches. In other embodiments, the drivable cart further includes a speedometer that measures the frequency of rotation of at least one wheel included in the drivable cart (202). As such, the speed of the drivable cart (202) may be determined given the frequency of rotation of the at least one wheel along with a knowledge of the diameter of the at least one wheel. An upper speed limit may be placed on the speed of the drivable cart (202). The upper speed limit may originate from a physical limitation of the drive mechanism of the drivable cart (202) (e.g., motor limitations) or may be governed according to a speed threshold. As will be described later, the speed threshold may be configured according to a usage situation of the robotic manipulation system (102).

[0050] As depicted in FIG. 3, the primary control interface (111) can include a boom position knob (306) that may be used to extend and retract, or enact other movement on, the boom (113). Further, the primary control interface (111) can include a boom height rocker switch (307) that can control the raising and lowering of the support column (204). Additionally, as further shown, the primary control interface (111) may include various buttons, such as emergency stop button (308) and power button (309) used to input an emergency stop command and power on and off the drivable cart (202), respectively.

[0051] Along with the controls described above, the primary control interface (111) can include a touchscreen (310). The touchscreen (310) can display a menu (not shown) providing additional control functionality of the drivable cart (202) to a user. For example, and as will be described in greater detail later in the instant disclosure, the touchscreen (310) may be used to, among other things, select a usage situation of the robotic manipulations system (102). The touchscreen (310) may provide visual feedback to a user. Further, it will be well understood that the primary control interface (111) may provide other suitable output mechanisms such as speakers, actuators, LEDs, buzzers, etc., for visual, audio, and / or other types of feedback (e.g., audible feedback, haptic feedback, etc.).

[0052] FIG. 4A depicts an example manipulator arm (400). The example manipulator arm (400) of FIG. 4A includes a base (402). The base (402) can be attached to a larger assembly, such as the depicted boom (113) in FIG. 4A, or other attachment location such as a rail or overhead mount. Typically, the base (402) is considered fixed in space duringoperation of the manipulator arm (400) such that operation of the manipulator arm (400) may be said to affect the position of a distal end (401) of the manipulator arm (400) relative to the base (402). In other words, the manipulator arm (400) can include a number of degrees of freedom between the base (402) and the distal end (401). The distal end (401) can be configured for the attachment of an instrument or tool. Herein, the term “tool” encompasses both general or industrial robotic tools and specialized robotic surgical instruments. Often, specialized robotic surgical instruments include a so-called “end effector” (e.g., end effector (403)) that is suitable for manipulation of tissue, treatment of tissue, imaging of tissue, or the like. For example, the end effector may be an actuatable gripping device. Attachment of a tool can be provided on the distal end (401) of the manipulator arm (400) through a quickdisconnect coupling or tool holder. Actuation of the end effector can be controlled by the manipulator arm (400) upon attachment of the tool.

[0053] As stated, operation of the manipulator arm (400) includes control of the position of the distal end (401) and / or a tool and end effector attached thereon relative to the base (402). Herein, the term “position” encompasses both location and orientation (e.g., translation and rotation). In minimally invasive scenarios, an instrument or tool may be positioned and manipulated through an entry location, so that a kinematic remote center is maintained at the entry location.

[0054] The manipulator arm (400) consists of a sequence of joints and links that move in coordination forming a kinematic configuration that determines the position of the distal end (401) and associated tool, if present. The joints of the robotic arm, in combination, may or may not have redundant degrees of freedom.

[0055] The manipulator arm (400) of FIG. 4A has ten labelled joints, namely, a first joint (Ji), a second joint (J2), and so on and so forth until the tenth joint (J10). In some instances, joints are connected by links. The manipulator arm (400) of FIG. 4A has seven links annotated as the first link (Li), second link (L2), and so on and so forth until the seventh link (L7). Generally, links provide a spatial separation between joints and introduce a greater range of motion to the manipulator arm (400). Joints can be rotary or prismatic. Joints, whether rotary or prismatic, may further be classified as driven or non-driven. Generally, non-driven joints do not have a motor and are positioned manually such as through physical contact by an operator. That said, non-driven joints may be configured for gravity compensation and may have an actuator. Additionally, in some embodiments, non-driven joints include a joint sensor to determine the state of the joint (e.g., position, velocity, acceleration) and a braking system (or, more simply, a “brake”) to maintain a stationaryposition of the joint relative to the base (402) or relative to a link proximal to the joint. An example brake of a non-driven joint is described later in the instant disclosure. Driven joints, in contrast, generally include a control board and a joint actuator, the joint actuator including all necessary components for operating and stopping the joint. For example, a joint actuator can include a motor, an encoder, gears, and / or a brake. In general, non-driven joints are manipulated to adjust a position of the kinematic remote center. Once a kinematic remote center is established, non-driven joints are fixed in place (e.g., through use of their brakes) and the driven joints are controlled to manipulate the distal end (401) of the manipulator arm (400) and / or end effector (403) while maintaining the kinematic remote center. The first, second, third, and fourth joints (Ji, J2, J3, and J4) of the example manipulator arm (400) of FIG. 4A may be considered non-driven joints while the remaining joints are driven joints.

[0056] The term “state” of a joint or the like will herein refer to the control variables associated with the joint. For example, the state of a rotary joint can include an angle (0) of the joint relative to an angular datum of the joint. Thus, the orientation of a rotary joint is known given its state or current angle. The state of a joint can further include the velocity (e.g., angular velocity (0)) at which the joint is moving. Similarly, the state of an axial or prismatic joint may refer to the joint’s axial position (x), and / or to its axial velocity (x). In one or more embodiments, the state of a joint is determined using, or based on, a joint sensor (e.g., non-driven joints) and / or a position encoder (e.g., included in the joint actuator of a driven joint). The joint sensor of a non-driven joint may be a position encoder. For driven joints, the control board of the joint can specify and determine the state of joint, where variations of the manipulator arm (400) may rely primarily or entirely on position controllers, acceleration controllers, or the like, where position, velocity, and acceleration can each be determined (or approximated) by each other using integration and derivation, where appropriate. Hence, movements of the driven joints and movements of an end effector, tool, and / or distal end (401) of the manipulator arm (400) described herein may be performed using a position control algorithm, a velocity control algorithm, a combination of both, and / or the like.

[0057] Thus, the kinematic configuration of the manipulator arm (400) is completely specified through the state of the joints in view of the relative positions and lengths / sizes of the intervening links, if any. In some instances, the kinematic configuration of the manipulator arm (400) may further include state information for position components external to the manipulator arm such as a boom (113) and support column (204). Operationof the manipulator arm (400), which primarily consists of controlling the manipulator arm (400) through a continuous space of joint states, is governed by a control system (142).

[0058] The control system (142) may perform at least some of the calculations to determine the kinematic configuration of the manipulator arm (400) and the sequence and timing of joint states that should be undertaken to achieve a desired kinematic configuration. Often, there will be many potential sequences of joint states that can achieve a desired kinematic configuration such that the control system (142) may also apply a constrained optimization routine to select a sequence of joint states (or select a path of traversal through a space of joint states) that is safe (i.e., avoids collisions between joints and links of the manipulator arm (400)) while optimizing some predefined criterion / criteria (e.g., a minimum length path through the space of joint states, maximizing the range of motion of all available joints upon achieving the desired kinematic configuration, etc.).

[0059] FIG. 4B depicts a simplified schematic view (450) of the example manipulator arm (400) depicted in FIG. 4A. In the simplified schematic view (450), rotary joints are represented as cylinders, prismatic joints are represented as dampers, and links are represented as solid lines with increased line thickness. Each joint defines a joint axis. The simplified schematic view (450) illustrates a joint axis for each joint (e.g., first axis of rotation (451)), axis of translation (e.g., first axis of translation (452), etc.). To avoid cluttering FIG. 4B, while all joint axes are illustrated, not all are labelled.

[0060] In the example manipulator arm (400), as depicted in FIG. 4B, the first joint (Ji) is directly connected to a base (402) (e.g., the distal end of the boom (113)). The second joint ( J2) , which is an axial or prismatic joint, has a proximal end in direct contact with the first joint (JI) and is coupled to the proximal end of the third joint (J3), through the first link (LI), on its distal end. As seen, the first link (LI) alters the direction of the kinematic chain of joints and links of the manipulator arm (400). The second link (L2) extends distally from the third joint (J3) and is connected to the fourth joint (J4) on its distal end. Similarly, the third link (L3) extends from the fourth joint (J4) and is connected to the fifth joint (J5) on its distal end. Proceeding distally, an alternating sequence of links and joints (e.g., fourth link (L5) to sixth joint (J6)) continues until the ninth joint (J9), at which point the tenth joint (J10) is directly connected.

[0061] As stated, the joints (e.g., non-driven joints) of a manipulator arm (e.g., manipulator arm (400)) may include a brake system (“brake”). The present disclosure places no limitation on the type or configuration of a brake so long a as a variable braking force may be applied. Herein, for consistency, the term “braking force” is used to describe the generalholding force applied by a brake system to an associated joint to prevent movement of said joint (rotation or translation), regardless of whether the joint is rotary or prismatic. As such, for rotary joints, or any joint that undergo some form of rotation, applied torques or moments may be referred to simply as applied forces. Variable braking force indicates that the general holding force applied to the associated joint by the brake is continuously adjustable (e.g., a continuous function of an analog voltage), or near-continuously adjustable (e.g., highly discretized). In general, the brake may be an electromagnetic brake or a mechanical brake (e.g., hydraulic, pneumatic, etc.).

[0062] FIG. 5 depicts an example spring actuated electromagnetic brake system (500) that may be included with a joint of the manipulator arm (400) (e.g., a non-driven joint). As illustrated, the spring actuated electromagnetic brake system (500) consists of a stator (502), a rotor (504) that may include a rotor hub (506), an armature (508), a plate (510), a spring (512), and a coil (514). In general, the stator (502) remains fixed or stationary relative to a local base such as the proximal end of an associated joint. The rotor (504) resides between the armature (508) and the plate (510), and, when no braking force is applied or when a sufficient force is applied to overcome the braking force, can rotate relative to the stator (502) about a first rotational axis (516). Without power, the spring (512) of the spring actuated electromagnetic brake system (500) pushes the armature (508) into the rotor (504) and the rotor (504) is consequently pushed into the plate (510). Contact of the armature (508) and the rotor (504), and the rotor (504) and the plate (510), results in friction between these components, where the frictional force (i.e., braking force) is proportional to the normal force (coaxial to the first rotational axis (516)) applied to the armature (508) by the spring (512).In some instances, high friction coefficient materials, or linings, may be applied to the contact surfaces of the armature (508), rotor (504), and plate (510) to increase the braking force for a given normal force. When powered, current, proportional to a supplied voltage, may flow through the coil (514) effectively creating an electromagnet from the stator (502). The electromagnet produces a magnetic force. The armature (508) is drawn toward the stator (502) by the magnetic force. The magnitude of the magnetic force is proportional to the current in the coil (514) and therefore the supplied voltage to the spring actuated electromagnetic brake system (500). The magnetic force can counteract the force of the spring (512) reducing the braking force and eventually allowing the rotor (504) to rotate given an applied force. In other words, in the spring actuated electromagnetic brake system (500), the rotor (504) rotates about the first rotational axis (516) proportionate to a net applied force (Fnet), where Fnet = sign(FaOpiied)*max(IFappiiedl - IFbnddngl, 0) and Fappiied is the appliedforce to the rotor, Fbraking is the braking force of the spring actuated electromagnetic brake system (500), the sign operator returns the sign of its enclosed parenthetical term, and the max operator returns the term with the highest value between its two or more enclosed parenthetical terms. Further, the braking force (Fbraking) is proportional to the normal force (Fnormai) exerted on the armature (508), where Fnormai = max(IFspringl-IFmagneticl, 0), where Fspring is the force applied to the armature (508) by the spring (512) and Fmagnetic is the counteracting force applied to the armature (508) by the electromagnet (i.e., created through current flowing in the coil (514) through the stator (502)).

[0063] In some instances, the polarity of the spring actuated electromagnetic brake system (500) can be reversed such that the magnetic force generated by the electromagnet acts with the spring (512) to push the armature (508) into the rotor (504). Thus, in these instances the braking force is increased and is given by Fbraking ~ Fnormai = Fspring + Fm gnetic, where - denotes proportionality.

[0064] In review, a spring actuated electromagnetic brake system (500) produces a braking force proportionate to a supplied voltage. The supplied voltage may be continuous or sufficiently discretized as to be nearly continuous (e.g., a bit depth of 12). Thus, a spring actuated electromagnetic brake system (500) produces a variable braking force. It is noted that while the braking force of the spring actuated electromagnetic brake system (500) is proportionate to the supplied voltage, the relationship between supplied voltage and braking force need not be linear. Further, the spring actuated electromagnetic brake system (500) prevents movement of a joint so long as the magnitude of the braking force exceeds the magnitude of an applied force imposed upon the joint.

[0065] Another example of a brake system that may be used in a joint (e.g., nondriven joint) of a manipulator arm (e.g., manipulator arm (400)) is an electromagnetic brake system. An electromagnetic brake system is similar in operation to a spring actuated electromagnetic brake system (500) except that, under normal operating conditions, the spring of the electromagnetic brake (sometimes distinguished by the term “leaf spring”) and the magnetic force of the electromagnetic brake have reverse roles. Namely, in an electromagnetic brake, the magnetic force, induced by a supplied voltage, serves to push the armature into the rotor and the leaf spring pushes the armature away from the rotor. Thus, under normal operation (i.e., without reversing polarity) a spring actuated electromagnetic brake system (500) reduces the braking force upon being powered (and applies a braking force without power) and an electromagnetic brake system increases the braking force upon being powered (and does not apply a braking force when not powered).

[0066] In accordance with one or more embodiments, the robotic manipulation system (102) can be used in, or encounter, various usage situations. FIG. 6 depicts a first usage situation for the robotic manipulation system (102). The first usage situation may also be known as a transportation of the robotic manipulation system (102) outside an operating room. FIG. 6 depicts an example floorplan (600) of a hospital or other medical facility. As seen, the medical facility includes a reception area (602), a hallway (604), a first operating room (606), a second operating room (608), and two auxiliary rooms (610) (e.g., storage areas, offices, etc.). The first usage situation consists of navigating the robotic manipulation system (102) from a first position (102-1) to a second position (102-2) along a first path (614), where the first path (614) resides or traverses, at least partially, an area outside of an operating room (e.g., hallway (604)). As illustrated in FIG. 6, the robotic manipulation system (102) is being transported from the first operating room (606) to the second operating room (608). FIG. 6 also depicts a person (612) present in the hallway (604). Consequently, to avoid a collision with the person (612), the first path (614) navigates the robotic manipulation system (102) around the person (612). In general, when transporting the robotic manipulation system (102) it is desirable to avoid colliding with objects (e.g., walls, overhead lights, etc.) or persons and to avoid damaging the robotic manipulation system (102), or components of the robotic manipulation system (e.g., manipulator arm (400)), and to prevent damage or injury to the proximate objects and persons, respectively.

[0067] FIG. 7 depicts a second usage situation for the robotic manipulation system (102), namely, a setup movement of the robotic manipulation system (102) inside an operating room (700). FIG. 7 depicts an operating room (700) with a computer-assisted system (100) including a robotic manipulation system (102), a user control system (104), and an auxiliary system (106). The operating room (700) further includes multiple obstacles (e.g., first obstacle (709), second obstacle (710), third obstacle (711), fourth obstacle). Examples of obstacles include an anesthesia cart, sink, instrument table, etc. The operating room (700) further includes an operating table (119). The second usage situation, or setup movement of the robotic manipulation system (102), may generally be defined as the positioning of the robotic manipulation system (102) within an operating room (700) in preparation for an upcoming procedure or operation. The setup movement of the robotic manipulation system (102) may include transporting the robotic manipulation system (102) from a third position (102-3), in the operating room (700), to a fourth position (102-4) approaching the operating table (119). FIG. 7 depicts the transportation of the robotic manipulation system (102) along a second path (702) that avoids the various obstacles in theoperating room (700). The setup movement of the robotic manipulation system (102) may further include draping one or more components (e.g., manipulator arm) of the robotic manipulation system (102). Draping, in general, consists of wrapping or enclosing portions of the robotic manipulation system (102) with one or more drapes to provide a sterile interface between components of the robotic manipulation system (102), such as a manipulator arm, and a patient. After the draping, the manipulator arms may remain in an extended configuration or may be returned to a stowed (folded) configuration.

[0068] FIG. 8 depicts a third usage situation for the robotic manipulation system (102). The third usage situation may be described a pre-procedure movement or docking approach of the robotic manipulation system (102). As seen in FIG. 8, the third usage situation may include transportation of the robotic manipulation system (102) from the fourth position (102-4), established during the second usage situation, to a fifth position (102-5), where the fifth position (102-5) is proximate the operating table (119). The fifth position (102-5) is such that, once positioned, a computer-assisted medical procedure may be performed on a patient with use of the robotic manipulation system (102) (e.g., by the at least one manipulator arm and associated instrument, if any) without further movement of the robotic manipulation system (102) as a whole. As illustrated, during the pre-procedure movement, the robotic manipulation system (102) may traverse a third path (802) towards the operating table (119). The pre-procedure movement or docking approach may further include draping one or more components (e.g., manipulator arm) of the drivable cart (e.g., when draping is not performed during the second usage situation). In some embodiments, the pre-procedure movement of the robotic manipulation system may further include an initial or approximate positioning of the at least one manipulator arm including extension of the support column (204), extension of the boom (113), and manipulation of one or more joints (e.g., non-driven joints) of a manipulator arm such that a meaningful kinematic remote center can be obtained and maintained for the procedure to be performed.

[0069] In accordance with one or more embodiments, the robotic manipulation system (102) further includes at least one drape sensor (not shown). The at least one drape sensor is configured to detect the presence of a drape on the robotic manipulation system (102) or a component of the robotic manipulation system (102) (e.g., manipulator arm). An example drape sensor is an inductance sensor that can detect an attached peripheral device containing a magnet, for example, in the case where a drape is attached to a manipulator arm with a magnet.

[0070] While three usage situations have been discussed, a distinction between any number of usage situations may be made, without departing from the disclosure.

[0071] In accordance with one or more embodiments, the computer-assisted system (e.g., computer-assisted system (100)) further includes a camera system (not shown). The camera system includes one or more cameras. Each camera of the camera system has a field of view (FOV). Field of view is used herein as a general term intended to indicate the extent of the observable world that is seen by a camera. Stated more technically, the field of view is a solid angle through which the detector of a camera is sensitive to electromagnetic radiation. Any type of camera technology, 2D or 3D, may be used. A camera may acquire images representative of the environment observable to the camera according to its FOV. In one or more embodiments, at least one of the one or more cameras of the camera system are disposed on the robotic manipulation system (102). In some embodiments, one or more cameras of the camera system may be disposed, for example, throughout an operating room in which the computer-assisted system is disposed.

[0072] In one or more embodiments, the computer-assisted system (100) may be outfitted with additional sensory systems. These sensory systems may include an ultrasonic system and a light detection and ranging (EiDAR) system each composed of one or more sources (e.g., ultrasonic transmitter, laser) and receivers or sensors. Similar to the camera system, sensors of any additional sensory system may be disposed on the robotic manipulation system (102) or throughout a surrounding environment encompassing, at least part of the computer-assisted system.

[0073] In general, in one or more embodiments, the computer-assisted system may be said to include at least one sensor, where the at least one sensor may be camera (of an included camera system), a drape sensor, a EiDAR sensor (of an included EiDAR system), and an ultrasonic sensor (of an included ultrasonic system). In accordance with one or more embodiments, sensor data (e.g., images) acquired by the at least one sensor (e.g., camera) of the computer-assisted system are processed to perform one or more of the following tasks: environment classification; object detection and classification; object avoidance; object proximity determination; and collision prediction.

[0074] Herein, environment classification consists of selecting a class, from a predefined set of classes, that describes the external surroundings or environment of the robotic manipulation system (102) of the computer-assisted system (100). In one or more embodiments, the pre-defined set of classes includes an “operating room environment” (i.e., within an operating room) and a “non-operating room environment” (e.g., hallway, storageroom, etc.). In other embodiments, the pre-defined set of classes includes an “operating room environment,” a “non-operating room environment,” and “an unknown or other environment.” A benefit to the latter pre-defined set of classes is that ambiguous environments can be indicated without forcing an assignation to either an operating room environment or non-operating room environment.

[0075] Object detection and classification includes both detecting the presence of an object in space (i.e., object localization) and assigning a class to the object where the class describes the object. With respect to object detection and classification, herein, the term “object” is broadly defined to include items conventionally considered objects (“generic objects”) such as walls, tables, chairs, plants, etc., but also people. In one or more embodiments, the object detection and classification task can further classify people as “patient” or “non-patient.”

[0076] In accordance with one or more embodiments, object avoidance encompasses the simultaneous self-locating and mapping of the surrounding environment of the robotic manipulation system (102), a process known as simultaneous localization and mapping (SLAM). Generally, SLAM is a method used principally by autonomous vehicles to map (spatially orient surrounding objects) and localize the vehicle in that map at the same time. A SLAM algorithm may be used to plan a path for the robotic manipulation system (102) to travel in order to safely arrive at desired destination (e.g., in an operating room). The SLAM algorithm can run in real-time or traceable time. Methods used by the SLAM algorithm may include, but are not limited to: particle filter; extended Kalman filter; and covariance intersection.

[0077] Object proximity determination includes determining, or at least approximating, the distance of one or more objects from the robotic manipulation system (102). In one or more embodiments, object proximity determination is performed through the joint use of an object segmentation process or model and a depth estimator. In general, a depth estimator, given an image, returns a depth field for the given image. The depth field indicates the distance, or depth, of every pixel in the image from the acquiring camera. The object segmentation process similarly processes a given image and segments the image into one or more objects. As such, a segmented object can be assigned a depth (or distance) by aggregating the depth field of the segmented object, where aggregation may include an average, minimum, or maximum operator applied pixelwise over the pixels enclosed by the segmented object. In other embodiments, object proximity determination is performed using an ultrasonic system or a LiDAR system, where at least the source and receiver of suchsystems are disposed on the robotic manipulation system (102). Still, in other embodiments, object proximity detection is performed using a stereoscopic technique with two or more cameras, where the two or more camaras may be disposed on the robotic manipulation system (102) or within a surrounding environment in view of the robotic manipulation system (102).

[0078] Collision prediction includes determining whether or not the robotic manipulation system (102) will collide with an object (e.g., wall, table, person: patient, nonpatient) given a current trajectory of the robotic manipulation system (102) and / or a given planned path that the robotic manipulation system (102) is traversing or is to traverse. For example, if the robotic manipulation system (102) is known to be proceeding toward an object, the distance to the object (i.e., object proximity determination) and the speed of the drivable cart (e.g., determined using the pressure sensor or speedometer) can be used to calculate a time to collision. If the time to collision is less than a pre-defined collision time threshold, then a collision may be predicted to be imminent. In such a case, the drivable cart may be automatically stopped, or slowed, to avoid collision.

[0079] While the tasks of environment classification, object detection and classification, object avoidance, object proximity determination, and collision prediction have been described separately, one with ordinary skill in the art will recognize that two or more of these tasks may be performed concurrently or in complimentary fashion (e.g., using a single process or model). In one or more embodiments, one or more of the aforementioned tasks are performed using one or more machine-learned models (e.g., a convolutional neural network (CNN)) and / or computer vision techniques operating on the sensor data (e.g., camera images, ultrasonic data, drape sensor, etc.). For example, regional based CNNs (R-CNNs) and / or single shot detectors (SSDs) (and their variants) may be employed for object detection and classification. In particular, in one or more embodiments, a You Only Look Once (YOLO) object detection model is employed for the object detection and classification task. Other machine-learned model types (e.g., vision transformer (ViT), neural network (NN), random forest (RF), etc.) and machine-learned model architectures, not explicitly referenced herein, may be used to perform any of the aforementioned tasks without departing from the scope of this disclosure. In accordance with one or more embodiments, one or more of the tasks of environment classification, object detection and classification, object avoidance, object proximity determination, and collision prediction are performed by a control system (142) of the computer-assisted system (100).

[0080] As discussed, non-driven joints of a manipulator arm (e.g., first manipulator arm (112)) of a robotic manipulation system (102) of a computer-assisted system (100), once positioned, may be held in position using brakes. The brakes can apply a well-resolved braking force (i.e., range of braking force is highly discretized or continuous). For example, in an electromagnetic brake system, the braking force is supplied by an electromagnet corresponding to a received voltage.

[0081] Embodiments of the disclosure control one or more of the brakes, for example, of the non-driven joint(s) of a manipulator arm (e.g., manipulator arm (400)) to facilitate detecting a collision between the manipulator arm and an object (e.g., a wall, a person, an equipment item). A collision may occur, for example when the entire robotic manipulation system (102) is moved, but also under other conditions. Embodiments disclosed herein relate to a system and method for modulating the braking force of a brake in a non-driven joint dynamically, and in real-time, based on at least one of: a usage situation, a kinematic configuration of the manipulator arm (including the configuration of the boom (113) and support column (204) of the robotic manipulation system (102)), and a speed of the drivable cart (e.g., determined using a pressure sensor associated with a drive switch of the primary control interface (111)). Furthermore, in some embodiments, modulation of the braking force may further depend on the detection of a patient and / or a determined proximity of the robotic manipulation system (102), or any of its components (e.g., manipulator arm), to the patient, if detected.

[0082] In general, an applied force exerted on a non-driven joint that exceeds a braking force of the non-driven joint will cause a displacement of that non-driven joint. The applied force may be imposed directly on the non-driven joint or may be an effect of a force or moment applied to any component of the manipulator arm distal to the given non-driven joint. Each non-driven joint of a manipulator arm includes a joint sensor (e.g., position encoder, torque approximator) that can sense joint movement (e.g., rotation, translation) of the non-driven joint. In one or more embodiments, a non-driven joint is associated with a movement threshold. If the sensed joint movement of a given non-driven joint exceeds its associated movement threshold, then a collision is said to have occurred at some location at, or distal to, the given non-driven joint. In one or more embodiments, the movement threshold of a non-driven joint is dependent on the location of the non-driven joint on the manipulator arm as well as the kinematic configuration of the manipulator arm. For example, a relatively proximal non-driven joint may have a smaller movement threshold than a moredistal non-driven joint. The movement threshold of a non-driven joint may be set to zero, or otherwise the smallest sensed joint movement as defined by the joint sensor.

[0083] The modulation of the braking force of a non-driven joint, in some embodiments, is performed such that only true collisions are detected (based on sensed joint movement), whereas applied forces imposed upon the non-driven joint not originating from a collision (e.g., inertial loads from the movement of the robotic manipulation system (102)) are not detected. Specifically, for example, modulating the brake of a non-driven joint to exert less braking force at the non-driven joint will allow smaller applied forces to cause detectable joint movement (i.e., exceeding the movement threshold), whereas tuning the same brake to exert more braking force at the joint may require larger forces to cause detectable joint movement. Accordingly, a brake may be tuned based on a current usage situation for optimal detection of collisions. Further, it may be desirable to limit the braking force (to a level below the braking force that is generated when the brake is fully engaged) such that a joint movement can occur without requiring a large force. It may further be desirable to set the braking force to at least a prespecified braking force such that displacement of the nondriven joint does not occur under normal movement of robotic manipulation system (102), or the associated manipulator arm of the non-driven joint, due to inertial loads, for example, while moving and stopping the drivable cart (202). Thus, in the present disclosure, the braking force each non-driven joint of a robotic manipulation system (102) is set to a force or torque threshold based on various factors that may be individualized to each non-driven joint, including: the current usage situation of the robotic manipulation system (102), the current kinematic configuration of the manipulator arm associated with a given non-driven joint, the speed of the drivable cart (202) (and perhaps the acceleration), and / or other factors.

[0084] A few examples of usage situations are subsequently discussed. For each usage situation, a possible tuning of the brake(s) that addresses the needs of operating in that usage situation is described. Importantly, in order to tune the brake(s), the usage situation must be known. Accordingly, the description of the usage situations is followed by a discussion of how the usage situations may be detected in order to tune the brake(s) as needed.

[0085] As previously discussed, a first usage situation may cover transportation of the robotic manipulation system (102) such that the robotic manipulation system (102) traverses a path (e.g., first path (614)) that is, at least partially, outside of an operating room (e.g., operating room (700)). During transportation, a manipulator arm (e.g., first manipulator arm (112)) of the robotic manipulation system (102) may collide with an object, where an objectmay be a person or a thing (e.g., wall, table, overhead light, etc.). In the first usage situation, the speed of the drivable cart (202) of the robotic manipulation system may be unrestricted or restricted to a first speed. Upon detecting a collision, e.g., when a manipulator arm collides with an obstacle such as a wall, the movement of the drivable cart (202) of the robotic manipulation system (102) may be allowed to continue. In other instances, upon detecting a collision, the drivable cart (202) may be forced to (i.e., automatically) stop and / or required to reverse direction before again proceeding in its original direction. Also, with the manipulator arms not being in a locked configuration (i.e., brakes not fully engaged), the kinematic configuration of the manipulator arm may change in response to the collision. In this usage situation, the brakes may be tuned to apply a braking force Fl that is appropriate for the detection of collisions at higher speed, while avoiding false positives.

[0086] A second usage situation may cover more limited movement of the drivable cart (202) of the robotic manipulation system (102). The second usage situation may apply, for example, inside an operating room (e.g., operating room (700)). Movement of the drivable cart (202) within an operating room may require the avoidance of equipment (e.g., other components of the computer-assisted system (100)), one or more users or medical staff, and / or the patient (if present). In the second usage situation, the speed of the drivable cart may be more restricted. For example, the speed of the cart may be restricted to a second speed where the second speed is strictly less than the first speed. Upon detecting a collision, the motion of the drivable cart (202) may still continue, although with the speed being limited. In other instances, upon detecting a collision, the drivable cart (202) is automatically stopped and / or required to reverse direction before again proceeding in its original direction. In this usage situation, the brakes may be tuned to apply a reduced braking force F2 (F2 < Fl) that is appropriate for the detection of collisions at lower speed and in a more delicate environment, while avoiding false positives.

[0087] A third usage situation may cover an even more limited movement of the drivable cart (202) of the robotic manipulation system (102). The third usage situation may apply, for example, when incremental movements are performed prior to a surgical procedure (i.e., a pre-procedure movement or docking approach). The docking approach is designed to reach a mechanical configuration of the robotic manipulation system (102) that allows coupling of a cannula that passes through an entry location (e.g., a natural orifice such as the throat or anus, or through an incision) to an instrument holder at the distal end of a manipulator arm (112), for subsequent insert of the instrument through the cannula. Such incremental movements may consist of positioning the at least one manipulator arm of therobotic manipulation system (102) within the range of motion of the at least one manipulator arm relative to a patient. In the third usage situation, the speed of the drivable cart (202) may be even more restricted. For example, the speed of the cart may be restricted to a third speed where the third speed is strictly less than the second speed. In the third usage situation, if movement of the drivable cart (202) has been stopped because of a detected collision, subsequent movement may be restricted to the reverse direction immediately prior to the collision. In some instances, upon an initial backtracking of the drivable cart (202), movement of the drivable cart (202) may be prohibited until receiving user input / confirmation (e.g., using the touchscreen (310)). Further, warnings may be provided to the user (audio signal, light signal, status message, etc.). In this usage situation, the brakes may be tuned to apply a minimal braking force F3 (F3 < F2) that is appropriate for the detection of collisions with a high sensitivity and at minimal speed, while avoiding false positives. During and after docking, no more movement of the drivable cart (202) is allowed (cart drive disabled), and the brake(s) of the non-driven joints may be fully locked and remain engaged.

[0088] In some embodiments the detection of usage situations and the resulting tuning of the brake(s) is continuously performed (e.g., in a loop) to enable dynamic or live adjustments as needed or desirable. For example, detection of a change in environment (e.g., from hallway to operating room) may result in a re-tuning of the brakes, as described. Similarly, when in the operating room, brakes may be re-tuned live, in a context-dependent manner. For example, more collision sensitivity may be desired when approaching a patient versus when approaching staff. Further, collision sensitivity may be dynamically increased according to proximity of the robotic manipulation system (102), or its one or more manipulator arms, to the patient.

[0089] The following discussion covers possible methods for detecting a current usage situation. In one or more embodiments, the usage situation is manually input by a user of the robotic manipulation system (102), for example, through selection of the usage situation using the touchscreen (310).

[0090] Usage situations may have certain characteristics that may be detectable in data. Accordingly various sensors may be used to collect different types of data that may be used to determine the usage situation. When a usage situation is determined through the use of sensor data, the usage situation, and all accompanying settings (e.g., speed restrictions, automatic stopping of the drivable cart (202), etc.), may be automatically applied to the robotic manipulation system (102). Or, in instances where a usage situation is input manuallyby a user, if a different usage situation is detected, the detected usage situation may override the previously manually input usage situation.

[0091] Sensors may include, for example, a camera. Image data obtained from the camera (and other sensor data) may be used to classify the environment (i.e., environment classification) and objects and persons in the environment (i.e., object detection and classification). For example, the environment classification may classify the environment of the robotic manipulation system (102) as an “operating room environment” or a “nonoperating room environment.” Further, the object detection and classification process(es) of the computer-assisted system may distinguish a patient from staff (or other users of the computer-assisted system) and may be able to classify different types of equipment in the operating room, etc.

[0092] Sensors may further include movement sensors such as wheel sensor (e.g., speedometer) on the drivable cart (202) that may report a velocity or frequency of rotation of at least one wheel. Speed may also be determined based on a user input (e.g., the user commanding a certain velocity of the drivable cart, magnitude of pressure applied to a drive switch, etc.).

[0093] Sensors may also include a drape sensor to detect whether the at least one manipulator arm of the robotic manipulation system (102) has been draped.

[0094] Other sensors may be included without departing from the disclosure.

[0095] First usage situation: A detection may be made, for example, using the camera. Classification of the image data may result in the detection of a hallway and / or other non-operating room environment. The detection, thus, indicates that the system is in a common, not particularly delicate environment. In response to the detection, the brakes may be tuned as previously discussed.

[0096] Second usage situation: A detection may be made, for example, using the camera. Classification of the image data may result in the detection of an operating room environment. The second usage situation may be distinguished from the third usage situation (also an operating room environment) based on, for example, the absence of the patient as detected using the camera, and / or a detection of an absence of draping by the drape sensor and / or by the camera. The detection, thus, indicates that the system is in a delicate environment, but that a medical procedure is not imminent. Accordingly, the second usage situation is assumed. In response to the detection, the brakes may be tuned as previously discussed.

[0097] Third usage situation: A detection may be made, for example, using the camera and the drape sensor. Classification of the image data may result in the detection of an operating room environment. Further, the presence of draping (detected by the drape sensor and / or the camera) may indicate that the robotic manipulation system (102), and other components of the robotic manipulation system (102) or the computer-assisted system, has been prepared for a medical procedure. Further, the presence of a patient (detected by the camera) may indicate that the medical procedure is imminent. The detection, thus, indicates that the system is in a delicate environment, and further that a medical procedure is imminent, and a docking approach may be the next step, prior to the medical procedure. Particularly careful operation is, thus, necessary. Accordingly, the third usage situation is assumed. In response to the detection, the brakes may be tuned as previously discussed.

[0098] In addition to the usage situations, other factors may affect the tuning of the brake(s). For example, the kinematic configuration of a manipulator arm may affect the tuning of the brake(s). A manipulator arm in an “extended” configuration relative to the nondriven joint provides greater leverage and greater inertia on the non-driven joint upon colliding with an object, compared to a manipulator arm that is in a compact “folded” configuration. Specific kinematic configurations may be associated with or may be typical for certain usage situations. For example, manipulator arms may be stowed away (in the folded configuration) for the first and potentially the second usage situation. Accordingly, the current kinematic configuration may also help determine the current usage situation, thereby affecting the tuning of the brake(s). Similarly, the speed of the drivable cart may affect the tuning of the brakes. For example, at higher speeds, a manipulator arm is more likely to move even in absence of collisions, e.g., during acceleration and braking.Accordingly, the brakes may be tuned to avoid arm movement that is merely based on inertia, thereby avoiding false positives in the detection of collisions. Furthermore, objects detected in the surrounding environment may also be indicative of the current usage situation, thereby affecting the tuning of the brake(s). For example, the presence of a patient suggests that the surrounding environment is an OR, thereby ruling out the first operating scenario. In addition, the patient on the operating table being within a certain distance may be indicative of the third operating scenario.

[0099] In one or more embodiments, a functional relationship between the force / torque threshold applied to a non-driven joint given the usage situation (which may be detected), the kinematic configuration of the associated manipulator arm, and speed of the cart (as well as known speed limits given the usage situation), may be parameterized by a set 1of calibration parameters, where the set of calibration parameters includes at least one calibration parameter. In general, each non-driven joint may have its own set of calibration parameters. In one or more embodiments, the set of calibration parameters for each nondriven joint are periodically determined through a sequence of physical tests defining a calibration procedure. Consequently, the set of calibration parameters for each non-driven joint may be updated with the evolution of time to account for changing brake system behavior (e.g., burnishing of the brake(s) with time).

[0100] FIGs. 9A and 9B depict fictional force and relative joint movement plots, respectively. While fictional (i.e., not based on observed data), these plots are illustrative of the dynamic modulation of a brake of a non-driven joint and the detection of a collision through sensed joint movement. The ordinate axis of the force plot of FIG. 9A represents a value of applied force imposed on a given non-driven joint of a manipulator arm. In the case of FIG. 9A, the applied force is given in normalized arbitrary units (a.u.). The abscissa axis represents time (e.g., seconds). FIG. 9A depicts an example force curve (901) indicating the applied force imposed on the given non-driven joint with respect to time. The force plot of FIG. 9A is also partitioned into six regions, referenced herein as the first region (902), second region (904), third region (906), fourth region (908), fifth region (910), and sixth region (912).

[0101] The ordinate axis of the relative joint movement plot of FIG. 9A represents a value of joint movement sensed on the given non-driven using its joint sensor (e.g., position encoder). Similar to FIG. 9A, the relative joint movement of FIG. 9B is displayed in arbitrary units (a.u.). For example, the units of the relative joint movement could be degrees for a rotary joint. The abscissa axis of FIG. 9B is identical to that of FIG. 9A and represents time (e.g., seconds). FIG. 9B depicts an example joint movement curve (907) indicating the sensed joint movement of the given non-driven joint relative to datum with respect to time. The relative joint movement plot of FIG. 9B is partitioned into the same regions as the force plot of FIG. 9A.

[0102] In the example of FIGs. 9A and 9B, the given non-driven joint is disposed on a robotic manipulation system (102) and the robotic manipulation system (102) is determined to be in the first usage situation (i.e., in a non-operating room environment) and will be transported. In the time elapsed during the first region (902), the robotic manipulation system (102) is stationary and without contact from any person or object. At this time, based on the kinematic configuration of the associated manipulator arm, the usage situation (i.e., first usage situation), and current speed of the cart (zero speed), the braking force of the givenjoint is set to a first force / torque threshold (903). In the second region (904) an operator instructs or otherwise commands the drivable cart (202) to move (e.g., by depressing a drive switch). At this point, due to the acceleration of the robotic manipulation system (102) and resistance to inertial loads of the manipulator arm, the non-driven joint experiences a temporary peak in applied force. As illustrated in FIG. 9B, the applied force in the second region (904) does not exceed the first force / torque threshold (903) and, consequently, the non-driven joint does not experience any joint movement (FIG. 9B).

[0103] In the third region (906), the drivable cart (202) achieves its maximum allowable speed (e.g., first speed) and the applied force imposed on the given non-driven joint experiences oscillations as the robotic manipulation system (102) proceeds down its path. In the fourth region, the speed of the drivable cart (202) is reduced. Noting the decreased speed of the cart, the control system (142) of the drivable cart (202) automatically adjusts the braking force of the given non-driven joint, reducing the braking force to the second force / torque threshold (905).

[0104] In the fifth region (910) the manipulator arm, on which the given non-driven joint is disposed, collides with an object (e.g., wall). The applied force imposed on the nondriven joint as a result of the collision of the manipulator arm exceeds the second force / torque threshold causing the non-driven joint to move. FIG. 9B depicts a non-zero movement threshold (909). Over a finite period, the movement of the non-driven joint, as sensed by the joint sensor, eventually exceeds the movement threshold (909). As such, a collision is detected. In this example, upon detecting a collision, the drivable cart (202) is configured to stop movement and the brake of the non-driven joint that detected the collision is configured to release. As such, the sixth region (912) depicts a stall in the relative joint movement (due to the stoppage of the drivable cart (202)) and a removal of applied force on the non-driven joint.

[0105] Turning to FIG. 10, a flowchart in accordance with one or more embodiments is shown. The flowchart of FIG. 10 depicts a method (1000) for computer-assisted systems. The method (1000) may be used to detect a collision distal to a non-driven joint of a manipulator arm of a computer-assisted system. The method may be executed on one or more processors, e.g., of the one or more control systems of the computer-assisted system.

[0106] While the various steps in the flowchart are presented and described sequentially, one of ordinary skill will appreciate that some or all of the steps may be executed in different orders, may be combined or omitted, and some or all of the steps may be executed in parallel. Additional steps may further be performed. Furthermore, the stepsmay be performed actively or passively. For example, some steps may be performed using polling or be interrupt driven in accordance with one or more embodiments of the disclosure.

[0107] Turning to the flowchart, in Step 1002, a usage situation for a robotic manipulation system of the computer-assisted system is determined. The robotic manipulation system includes a manipulator arm consisting of at least one non-driven joint. In one example, the usage situation is determined through reception of a manual input from a user or operator of the drivable cart. For example, the robotic manipulation system may have an integrated primary control interface by which a user or operator of the robotic manipulation system may indicate the usage situation of the robotic manipulation system. The computer-assisted system can include one or more sensors, such as a camera or ultrasonic sensor (and associated ultrasonic or acoustic source). The one or more sensors can be disposed on any component of the computer-assisted system (e.g., the robotic manipulation system) or can be proximate to, or in view of, the robotic manipulation system (e.g., disposed within the surroundings of the robotic manipulation system). Sensor data are collected from the one or more sensors. In one example, the speed of the drivable cart may be used to determine the usage situation. A first usage scenario (e.g., as illustrated in FIG. 6) is typically associated with higher speeds of the drivable cart, whereas a third usage scenario (e.g., as illustrated in FIG. 8) is typically associated with minimal speeds of the drivable cart. A second usage scenario (e.g., as illustrated in FIG. 7) may be associated with intermediate speeds of the drivable cart. Accordingly, the actual speed of the drivable cart may serve as a meaningful predictor for the current usage situation. Alternatively, or in addition to manual input of the usage situation, the sensor data (e.g., images, drape sensor data) are processed to determine the usage situation. Determination of the usage situation from the sensor data can occur automatically and be performed by one or more control systems of the computer- assisted system. Each control system including at least one computer processor.

[0108] In Step 1004, the kinematic configuration of the manipulator arm is determined. The kinematic configuration of the manipulator arm is completely specified through the state of the joints in view of the relative positions and lengths / sizes of the intervening links, if any. The kinematic configuration of the manipulator arm may further include state information for position components external to the manipulator arm such as a boom and support column of the robotic manipulation system. In one example, the state of a joint is determined using, or based on, a joint sensor (e.g., non-driven joints) and / or a position encoder (e.g., included in the joint actuator of a driven joint). The joint sensor of a nondriven joint may be a position encoder. Again, one or more control systems of the computer-assisted system may perform at least some of the calculations to determine the kinematic configuration of the manipulator arm.

[0109] In Step 1006, a movement threshold for each non-driven joint of the manipulator arm is obtained. The movement threshold specifies an allowable movement for a given joint, where absolute joint movements within the movement threshold do not result in a detected collision. For example, in some embodiments, the movement threshold is set to prevent inertial effects from being detected as collisions. Inertial effects may be a result of, for example, the drivable cart encountering a bump on the floor, causing some shaking. In some embodiments, the movement threshold is further set to allow detection of even relatively minor collisions at joints and links of the manipulator arm. In other words, the movement threshold may be a tradeoff between allowing movement associated with collisions (even minor collisions) at joints and links, while preventing movement associated with inertial effects. The movement threshold may be tunable. In some instances, the movement threshold of a given joint is set to zero, or otherwise not used, such that a joint movement exceeding the minimum measurable (or sensed) joint movement by the joint sensor of the given non-driven joint is indicative of a collision.

[0110] In Step 1008, for each non-driven joint of the manipulator arm a force or torque threshold is determined. The force / torque threshold(s) are based on, at least, the usage situation and the kinematic configuration. In some instances, the force / torque threshold(s) may further be based on sensor data (e.g., speed of cart, drape sensor, proximity to a detected patient, etc.). Additionally, in Step 1008, the force / torque threshold(s) are adjusted dynamically, in real-time, as dictated by changes in the usage situation, kinematic configuration (and all other factors used in the determination of the force / torque threshold (s)). The force / torque threshold of a given non-driven joint may further be configured by a set of calibration parameters. In some embodiments, the force / torque threshold is set such that the previously described inertial effects do not result in movement at the non-driven joint. While an actual collision of the drivable cart (but not the encountering of a bump by the drivable cart) would, have the potential to cause moment at the non-driven joint as a result of the significant inertial effects, the force / torque threshold does not need to be set to accommodate such collisions because a collision of the drivable cart would stop further movement of the drivable cart.

[0111] In Step 1010, the braking force of each non-driven joint of the manipulator arm is set to its respective force / torque threshold as determined in Step 1008. In one or more embodiments, the braking force for a given non-driven joint is applied by a braking system(e.g., a spring actuated electromagnetic braking system) where the braking force is proportionate to a supplied input variable (e.g., voltage) and the supplied input variable is continuous (e.g., analog) or highly discretized (e.g., a bit depth of 12). Changes in force / torque threshold(s) determined in Step 1008 are applied in real-time, or modulated, in Step 1010.

[0112] In Step 1012, the joint movement of each non-driven joint is monitored. Joint movement is sensed using a joint sensor (e.g., position encoder) of each non-drive joint. Thus, the join sensor can sense, or measure, joint movement (e.g., rotation, translation) of its associated non-driven joint.

[0113] In Step 1014, for each non-driven joint, the joint movement (see Step 1012) of the non-driven joint is compared to its associated movement threshold (see Step 1006). As such, Step 1014 represents a decision. If, for any non-driven joint, the joint movement of the non-driven joint exceeds its associated movement threshold, a collision is said to have occurred and the flowchart of FIG. 10 proceeds to Step 1016. In this case, a collision is detected. Alternatively or additionally, a similar decision may be made based on a total end effector movement compared against a total end effector movement threshold determined based on the kinematic chain of the manipulator arm. Upon detecting the collision (a collision that applies a force / torque to at least one non-driven joint that exceeds its associated force / torque threshold), a collision procedure is applied. A default collision procedure involves automatically stopping the drivable cart or slowing down the drivable cart and raising one or more audiovisual alarms or notifications. Alarms or notifications can include an audible sound, flashing lights on the affected manipulator alarm, and a displayed text message or graphic. In such a case, the collision procedure may further require that an operator of the drivable cart clear the alarm or notification (e.g., after adjusting the manipulator arm and / or drivable cart to resolve the collision), provide a manual override to the detected collision, and / or require the temporary reversal of the direction of the drivable cart before again proceeding in the previously undertaken direction. In some instances, the collision procedure may be dependent on the usage situation at the time the collision occurred and was detected. For example, a collision procedure for the first usage situation may not require the drivable cart to stop upon detecting a collision.

[0114] If, in Step 1014, none of non-driven joints have experienced joint movement in excess of their associated movement thresholds, no collision is detected, and the flowchart returns to Step 1008. In this way, the manipulator arm of the drivable cart is continually monitored for collisions, where collision sensitivity is adapted through application of variablebraking forces of the non-driven joints; the variable braking forces based on, at least, the usage situation and kinematic configuration.

[0115] While not shown, the execution of the method (1000) may, at least periodically, return to Step 1002, in order to determine whether the usage situation has changed.

[0116] Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

Claims

CLAIMSWhat is claimed is:

1. A computer-assisted system comprising: a robotic manipulation system with a manipulator arm comprising: a non-driven joint, comprising: a joint sensor configured to sense joint movement of the non-driven joint, and a brake that applies a braking force to the non-driven joint; and a control system configured to: modulate the braking force of the brake based on a current usage situation of the computer-assisted system such that a force or torque at the nondriven joint causes a movement of the non-driven joint, the force or torque being caused by a collision of the manipulator arm distal to the non-driven joint and exceeding a force or torque threshold set based on the current usage situation; and determine whether a collision has occurred based on whether the movement of the non-driven joint is detected by the joint sensor.

2. The computer-assisted system of claim 1, wherein modulating of the braking force based on the current usage situation is continuously performed in real-time.

3. The computer-assisted system of claim 1, wherein the robotic manipulation system further comprises a drivable cart, with the manipulator arm disposed on the drivable cart, and wherein the current usage situation is one of: a first usage situation defined as transportation of the drivable cart outside an operating room, a second usage situation defined as setup movements of the drivable cart inside the operating room, and a third usage situation defined as pre -procedure movements of the drivable cart inside the operating room.

4. The computer-assisted system of claim 3, wherein modulating the braking force when the current usage situation is the first usage situation comprises setting the braking force higher than when the current usage situation is the second usage situation.

5. The computer-assisted system of claim 3, wherein modulating the braking force when the current usage situation is the second usage situation comprises setting the braking force higher than when the current usage situation is the third usage situation.

6. The computer-assisted system of claim 3, wherein: when the current usage situation is the first usage situation and it is determined that a collision has occurred, a driving of the drivable cart is allowed to continue.

7. The computer-assisted system of claim 3, wherein: when the current usage situation is the second usage situation and it is determined that a collision has occurred, a driving of the drivable cart is allowed to continue at a reduced speed.

8. The computer-assisted system of claim 3, wherein: when the current usage situation is the third usage situation and it is determined that a collision has occurred, a driving of the drivable cart is stopped.

9. The computer-assisted system of claim 8, wherein after stopping the driving of the drivable cart, the driving of the drivable cart is allowed only in a reverse direction, away from the collision.

10. The computer-assisted system of claim 1, wherein the robotic manipulation system further comprises a drivable cart, with the manipulator arm disposed on the drivable cart, wherein the computer-assisted system further comprises at least one sensor, and wherein the control system is further configured to determine the current usage situation using the at least one sensor.

11. The computer-assisted system of claim 10, wherein determining the current usage situation using the at least one sensor is continuously performed in real-time.

12. The computer-assisted system of claim 10, wherein the at least one sensor comprises a camera, and wherein determining the current usage situation comprises classifying a current environment of the robotic manipulation system based on image data obtained from the camera.

13. The computer-assisted system of claim 12, wherein the current environment, based on the classification, is a non-operating room environment, and wherein determining the current usage situation, based on the classification, comprises determining that the current usage situation is a first usage situation defined as transportation of the robotic manipulation system outside an operating room.

14. The computer-assisted system of claim 12, wherein the at least one sensor further comprises a drape sensor, and wherein determining the current usage situation comprises classifying a current environment of the robotic manipulation system based on image data obtained from the camera, and determining whether the manipulator arm is draped.

15. The computer-assisted system of claim 14, wherein the current environment, based on the classification, is an operating room environment, wherein the manipulator arm is not draped, and wherein determining the current usage situation comprises, based on the classification and the manipulator arm not being draped, determining that the current usage situation is a second usage situation defined as setup movements of the robotic manipulation system inside an operating room.

16. The computer-assisted system of claim 14, wherein the current environment, based on the classification, is an operating room environment, wherein the manipulator arm is draped, and wherein determining the current usage situation comprises, based on the classification and the manipulator arm being draped, determining that the current usage situation is a third usage situation defined as pre-procedure movements of the robotic manipulation system inside an operating room.

17. The computer-assisted system of any of claims 1-16, wherein modulating the braking force comprises requiring at least a prespecified braking force to hold a kinematic configuration of the manipulator arm absent the collision.

18. The computer-assisted system of any of claims 1-16, wherein modulating the braking force comprises adjusting the braking force based on a current kinematic configuration of the manipulator arm.

19. The computer-assisted system of claim 18, wherein modulating of the braking force based on the current kinematic configuration is continuously performed in real-time.

20. The computer-assisted system of any of claims 1-16, wherein the manipulator arm further comprises another non-driven joint, the another non-driven joint disposed distally to the non-driven joint.

21. The computer-assisted system of claim 20, wherein modulating the braking force comprises setting the braking force of the non-driven joint higher than the another non-driven joint.

22. The computer-assisted system of claim 1, wherein the robotic manipulation system further comprises a drivable cart with the manipulator arm disposed on the drivable cart, and wherein modulating the braking force comprises adjusting the braking force based on a speed of the drivable cart.

23. The computer-assisted system of claim 22, wherein the computer-assisted system further comprises at least one sensor, and wherein the control system is further configured to determine the speed of the drivable cart using the at least one sensor.

24. The computer-assisted system of claim 23, wherein determining the speed of the drivable cart using the at least one sensor is continuously performed in real-time.

25. The computer-assisted system of claim 23, wherein the at least one sensor comprises a pressure sensor configured to sense a pressure applied to a primary control interface of the drivable cart, and wherein determining the speed of the drivable cart comprises calculating the speed of the drivable cart based on the pressure.

26. The computer-assisted system of any of claims 1-16, wherein the non-driven joint further comprises an actuator.

27. The computer-assisted system of any of claims 1-16, wherein the non-driven joint is configured to compensate for effects of gravity.

28. The computer-assisted system of claim 1, wherein the robotic manipulation system further comprises a drivable cart with the manipulator arm disposed on the drivable cart, and wherein the computer-assisted system further comprises at least one sensor and wherein the control system is further configured to detect and classify a first object proximate the drivable cart using the at least one sensor.

29. The computer-assisted system of claim 28, wherein the at least one sensor comprises a camera, and wherein detection and classification of the first object is based on image data obtained from the camera.

30. The computer-assisted system of claim 29, wherein the first object, based on the classification, is one of: a generic object, a nonpatient, and a patient.

31. The computer-assisted system of claim 30, wherein modulating the braking force when the first object is the generic object comprises setting the braking force higher than when the first object is the non-patient.

32. The computer-assisted system of claim 30, wherein modulating the braking force when the first object is the non-patient comprises setting the braking force higher than when the first object is the patient.

33. The computer-assisted system of any of claims 1-16, wherein the manipulator arm further comprises a driven joint distal to the non-driven joint, the driven joint comprising a motor, a control board, and a position encoder.

34. The computer-assisted system of claim 33, wherein the force or torque at the nondriven joint, caused by a collision of the manipulator arm distal to the non-driven joint, originated at the driven joint or distal to the driven joint.

35. A method for collision detection in a computer-assisted system using sensed joint movement of a robotic manipulation system with a manipulator arm comprising: a non-driven joint, comprising: a joint sensor configured to sense joint movement of the non-driven joint, and a brake that applies a braking force to the non-driven joint, and wherein the method comprises: modulating the braking force of the brake based on a current usage situation of the computer-assisted system such that a force or torque at the nondriven joint causes a movement of the non-driven joint, the force or torque being caused by a collision of the manipulator arm distal to the non-driven joint and exceeding a force or torque threshold set based on the current usage situation; and determining whether a collision has occurred based on whether the movement of the non-driven joint is detected by the joint sensor.

36. The method of claim 35 wherein modulating of the braking force based on the current usage situation is continuously performed in real-time.

37. The method of claim 35, wherein the robotic manipulation system further comprises a drivable cart, with the manipulator arm disposed on the drivable cart, and wherein the current usage situation is one of: a first usage situation defined as transportation of the drivable cart outside an operating room, a second usage situation defined as setup movements of the drivable cart inside the operating room, and a third usage situation defined as pre -procedure movements of the drivable cart inside the operating room.

38. The method of claim 37, wherein modulating the braking force when the current usage situation is the first usage situation comprises setting the braking force higher than when the current usage situation is the second usage situation.

39. The method of claim 37, wherein modulating the braking force when the current usage situation is the second usage situation comprises setting the braking force higher than when the current usage situation is the third usage situation.

40. The method of claim 37, wherein: when the current usage situation is the first usage situation and it is determined that a collision has occurred, a driving of the drivable cart is allowed to continue.

41. The method of claim 37, wherein: when the current usage situation is the second usage situation and it is determined that a collision has occurred, a driving of the drivable cart is allowed to continue at a reduced speed.

42. The method of claim 37, wherein: when the current usage situation is the third usage situation and it is determined that a collision has occurred, a driving of the drivable cart is stopped.

43. The method of claim 42, wherein after stopping the driving of the drivable cart, the driving of the drivable cart is allowed only in a reverse direction, away from the collision.

44. The method of claim 35, wherein the robotic manipulation system further comprises a drivable cart, with the manipulator arm disposed on the drivable cart, wherein the robotic manipulation system further comprises at least one sensor, and wherein the method further comprises determining the current usage situation using the at least one sensor.

45. The method of claim 44, wherein determining the current usage situation using the at least one sensor is continuously performed in real-time.

46. The method of claim 44, wherein the at least one sensor comprises a camera, andwherein determining the current usage situation comprises classifying a current environment of the robotic manipulation system based on image data obtained from the camera.

47. The method of claim 46, wherein the current environment, based on the classification, is a non-operating room environment, and wherein determining the current usage situation, based on the classification, comprises determining that the current usage situation is a first usage situation defined as transportation of the robotic manipulation system outside an operating room.

48. The method of claim 46, wherein the at least one sensor further comprises a drape sensor, and wherein determining the current usage situation comprises classifying a current environment of the robotic manipulation system based on image data obtained from the camera, and determining whether the manipulator arm is draped.

49. The method of claim 48, wherein the current environment, based on the classification, is an operating room environment, wherein the manipulator arm is not draped, and wherein determining the current usage situation comprises, based on the classification and the manipulator arm not being draped, determining that the current usage situation is a second usage situation defined as setup movements of the robotic manipulation system inside an operating room.

50. The method of claim 48, wherein the current environment, based on the classification, is an operating room environment, wherein the manipulator arm is draped, and wherein determining the current usage situation comprises, based on the classification and the manipulator arm being draped, determining that the current usagesituation is a third usage situation defined as pre-procedure movements of the robotic manipulation system inside an operating room.

51. The method of any of claims 35-50, wherein modulating the braking force comprises requiring at least a prespecified braking force to hold a kinematic configuration of the manipulator arm absent the collision.

52. The method of any of claims 35-50, wherein modulating the braking force comprises adjusting the braking force based on a current kinematic configuration of the manipulator arm.

53. The method of claim 52, wherein modulating of the braking force based on the current kinematic configuration is continuously performed in real-time.

54. The method of any of claims 35-50, wherein the manipulator arm further comprises another non-driven joint, the another non-driven joint disposed distally to the nondriven joint.

55. The method of claim 54, wherein modulating the braking force comprises setting the braking force of the non-driven joint higher than the another non-driven joint.

56. The method of claim 35, wherein the robotic manipulation system further comprises a drivable cart with the manipulator arm disposed on the drivable cart, and wherein modulating the braking force comprises adjusting the braking force based on a speed of the drivable cart.

57. The method of claim 56, wherein the computer-assisted system further comprises at least one sensor, and wherein the method further comprises determining the speed of the drivable cart using the at least one sensor.

58. The method of claim 57, wherein determining the speed of the drivable cart using the at least one sensor is continuously performed in real-time.

59. The method of claim 57, wherein the at least one sensor comprises a pressure sensor configured to sense a pressure applied to a primary control interface of the drivable cart, and wherein determining the speed of the drivable cart comprises calculating the speed of the drivable cart based on the pressure.

60. The method of any of claims 35-50, wherein the non-driven joint further comprises an actuator.

61. The method of any of claims 35-50, wherein the non-driven joint is configured to compensate for effects of gravity.

62. The method of claim 35, wherein the robotic manipulation system further comprises a drivable cart with the manipulator arm disposed on the drivable cart, and wherein the computer-assisted system further comprises at least one sensor and wherein the method further comprises detecting and classifying a first object proximate the drivable cart using the at least one sensor.

63. The method of claim 62, wherein the at least one sensor comprises a camera, and wherein detection and classification of the first object is based on image data obtained from the camera.

64. The method of claim 63, wherein the first object, based on the classification, is one of: a generic object, a nonpatient, and a patient.

65. The method of claim 64, wherein modulating the braking force when the first object is the generic object comprises setting the braking force higher than when the first object is the non-patient.

66. The method of claim 64, wherein modulating the braking force when the first object is the non-patient comprises setting the braking force higher than when the first object is the patient.

67. The method of any of claims 35-50, wherein the manipulator arm further comprises a driven joint distal to the non-driven joint, the driven joint comprising a motor, a control board, and a position encoder.

68. The method of claim 67, wherein the force or torque at the non-driven joint, caused by a collision of the manipulator arm distal to the non-driven joint, originated at the driven joint or distal to the driven joint.

69. A non-transitory machine-readable medium comprising a plurality of machine- readable instructions executed by one or more processors associated with a computer- assisted system, the plurality of machine-readable instructions causing the one or more processors to perform the method of any of claims 35 to 68.

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