WO2014088965A2

WO2014088965A2 - Apparatuses, systems and methods for force feedback

Info

Publication number: WO2014088965A2
Application number: PCT/US2013/072669
Authority: WO
Inventors: Joseph AARON; Charles SIDOTI; Charles O'connell
Original assignee: Northeastern University Boston
Current assignee: Northeastern University Boston
Priority date: 2012-12-03
Filing date: 2013-12-02
Publication date: 2014-06-12
Anticipated expiration: 2015-06-03
Also published as: WO2014088965A3

Abstract

Apparatuses, systems and methods of the present disclosure are directed generally to providing force feedback in a mechanical manner by dissipating energy via a frictional disk. Further, apparatuses, systems and methods of the present disclosure can adjust the amplification force without changing a mechanical motion.

Description

APPARATUSES, SYSTEMS AND METHODS FOR FORCE FEEDBACK

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority of United States Provisional Patent Application No. 61/732,758, filed December 3, 2012, which is incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

Humans can only detect force differences above a certain threshold. The percent difference in force that a human can detect depends on the magnitude of the force. For example, for forces ranging from 0.5-200 Newtons (0.11— 45 pounds), a human can detect differences as small as 7-10% of the applied force. For forces under this range, for example, the detectable differences may be 15-27%. Depending on the range within which an actuation force falls, it may be challenging for a human to detect a magnitude of the actuation force.

SUMMARY Apparatuses, systems and methods of the present disclosure are directed generally toward providing force feedback in a mechanical manner without requiring the use of electronic sensors. Further, apparatuses, systems and methods of the present disclosure can adjust the amplification force without changing a mechanical motion of the apparatus.

At least one aspect is directed to an apparatus for providing force feedback. In some embodiments, the apparatus includes an actuator coupled to a lever arm via a proximal shaft. The actuator can be configured to rotate the proximal shaft. The apparatus can include a frictional disk coupled to a distal portion of the lever arm. An axis of the frictional disk can be separated from the proximal shaft by a separation distance. The apparatus can include a first gear coupled to the frictional disk. The first gear can be configured to rotate the frictional disk about the proximal shaft and allow the frictional disk to spin about the axis of the frictional disk. The apparatus can include a second gear that meshes with the first gear. The second gear can be configured to rotate the frictional disk about the proximal shaft. The apparatus can include a frictional element coupled to a distal shaft. The distal shaft may be different from the proximal shaft and not directly coupled to one another. The frictional element can be configured to generate friction between the frictional element and the frictional disk. The frictional element can be configured to rotate the distal shaft. Upon actuation of the actuator, the frictional element can generate friction between the frictional element and the frictional disk as the frictional disk orbits about the central shaft and spins about its own axis. As the frictional disk pushes against the frictional element, the frictional element can rotate the distal shaft.

In some embodiments, the second gear is rotationally fixed. In some embodiments, the frictional disk is further configured to push against the frictional element as the frictional disk orbits about the proximal shaft.

In some embodiments, an amplified force is observed at the actuator. In some embodiments, the amplified force corresponds to a coefficient of friction between the frictional disk and the frictional element, a shaft radius of the lever arm, a first diameter of the first gear, a second diameter of the second gear, and the separation distance between the axis of the frictional disk and the proximal shaft. In some embodiments, the amplified force observed at the actuator is proportional to the separation distance between the axis of the frictional disk and the proximal shaft. In some embodiments, the amplified force is proportional to a sum of a force of the first gear and a force corresponding to a normal force on torque at the distal shaft. In some embodiments, the force of the first gear is proportional to a frictional force on the frictional disk, proportional to a radius of the frictional disk, and inversely proportional to a radius of the first gear.

In some embodiments, each component of the apparatus is configured to be sterilized. In some embodiments, the actuator includes a handle with a rack configured to drive a pinion gear. The actuator can also include a bevel gear coupled to the proximal shaft. The bevel gear can be fixed to the pinion gear. Upon actuation of the actuator, the actuator rotates the pinion gear, the bevel gear, the proximal shaft.

At least one aspect is directed to a hernia mesh fixation device. In some

embodiments, the device includes an actuator coupled to a lever arm via a proximal shaft. The actuator can include a handle with a rack configured to drive a pinion gear. The actuator can further include a bevel gear coupled to the proximal shaft. The bevel gear can be fixed to the pinion gear. Upon actuation of the actuator, the actuator can rotate the pinion gear, the bevel gear, the proximal shaft. The apparatus can include a frictional disk coupled to a distal portion of the lever arm. An axis of the frictional disk can be separated from the proximal shaft by a separation distance. The apparatus can include a first gear coupled to the frictional disk. The first gear can be configured to rotate the frictional disk about the proximal shaft and allow the frictional disk to spin about the axis of the frictional disk. The apparatus can include a second gear that meshes with the first gear and is rotationally fixed. The apparatus can include a frictional element coupled to a distal shaft and configured to generate friction between the frictional element and the frictional disk.

In some embodiments, upon actuation of the actuator, the frictional element applies friction to the frictional disk as the frictional disk orbits about the proximal shaft and rotates about its own axis. As the frictional disk pushes against the frictional element, the frictional element rotates the distal shaft. In some embodiments, the pinion gear and the bevel gear are coupled to the proximal shaft. In some embodiments, the actuator provides an amplification factor.

At least one aspect is directed to a method for providing force feedback in a sterile environment. The method can include rotating, by an actuator coupled to a lever arm via a proximal shaft, the proximal shaft. The method can include orbiting and rotating, via a first gear coupled to a frictional disk, the frictional disk about the proximal shaft and about an axis of the frictional disk, respectively. For example, the frictional disk may orbit about the proximal shaft, while rotating about its own axis. The frictional disk can be coupled to a distal portion of the lever arm, and an axis of the frictional can be disk separated from the proximal shaft by a separation distance. The method can include engaging a second gear with the first gear. The method can include generating, by a frictional element coupled to a distal shaft, responsive to actuation of the actuator, friction between the frictional element and the frictional disk as the frictional disk orbits about the second gear and rotates about its own axis. The method can include generating an amplified force that is an amplification of a force at the distal shaft.

In some embodiments, the method can include dissipating energy based on a coefficient of friction between the frictional disk and the frictional element. In some embodiments, the amplified force is proportional to the separation distance between the axis of the frictional disk and the proximal shaft. In some embodiments, the amplified force is proportional to a sum of a force of the first gear and a force corresponding to a normal force on torque at the distal shaft. In some embodiments, the force of the first gear is proportional to a frictional force on the frictional disk, proportional to a radius of the frictional disk, and inversely proportional to a radius of the first gear. In some embodiments, each component used to generate the amplified force is sterilized.

BRIEF DESCRIPTION OF THE DRAWINGS

The details of one or more embodiments of the subject matter described in this specification are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages of the subject matter will become apparent from the description, the drawings, and the claims.

FIG. 1 is an illustrative block diagram of one embodiment of a force feedback system.

FIG. 2 is an illustration of one embodiment of an example apparatus for providing force feedback.

FIG. 3 is an illustration of one embodiment of an example apparatus for providing force feedback.

FIG. 4 is an illustration of a block diagram for calculating an amplification factor for one embodiment of an apparatus for providing force feedback.

FIG. 5 is an illustration of one embodiment of a method for providing force feedback in a sterile environment. FIG. 6 is a block diagram illustrating a general architecture for a computer system that may be employed to implement various elements of the systems and methods described herein, in accordance with an embodiment.

Like reference numbers and designations in the various drawings indicate like elements.

DETAILED DESCRIPTION Apparatuses, systems and methods of the present disclosure are directed generally to providing force feedback in a mechanical manner without requiring the use of electronic sensors. Further, apparatuses, systems and methods of the present disclosure can adjust the amplification factor without changing a mechanical motion. In an illustrative embodiment, the present technology is directed to apparatuses, systems and methods that provide a surgeon with "biofeedback", which, in the context of hernia mesh fixation, refers to the surgeon's ability to feel whether or not a fastener was properly inserted during surgery. During surgery, a surgeon squeezes a handle of a hernia mesh fixation device which rotates a distal end of the device in order to screw a fastener into tissue. The number of rotations and axial distance traveled may be referred to as the mechanical motion, and mechanical motion may need to be fixed in order to properly insert the fastener, for example. In order to feel whether or not a fastener was properly inserted, the miniscule force seen at the fastener during delivery is amplified into the handle of the system. Thus, when the surgeon pulls the handle, a greater force will be felt if the fastener is being driven into tissue as opposed to a failed delivery into no tissue.

More specifically, and in some embodiments, the system includes a rotating frictional disk on a lever arm that is driven by an actuator/handle on the proximal portion of the rotator. As the fastener is rotated into tissue, the frictional disk pushes against a frictional element that is attached to the distal portion of the rotator. As the torque to deliver a fastener increases, the normal force between the lever arm and frictional disk increases, intensifying the required depression force to the actuator/handle. This system supplies feedback that signifies a successful delivery to the user, which appeals to surgeons. Systems, apparatuses, and methods of the present disclosure can be implemented in any rotational system and could be adapted for a linear system as well.

FIG. 1 illustrates the general concepts used to amplify force in one embodiment of a force feedback system 100. In brief overview, the system 100 includes a distal portion 105 (or a connection to a distal portion) that delivers a drive force and generates a resistive force. The system 100 includes a force transmission element 110 that mechanically transmits, conveys, transfers or otherwise provides the resistive force generated at the distal portion 105 to a frictional element 115. The system 100 includes the frictional element 1 15 that receives the resistive force. The system 100 can include a frictional disk. The resistive force can be applied as a normal force to the frictional disk 120 via the frictional element 115. The system 100 includes a shaft 125 that is configured to rotate the frictional disk 120. The system 100 includes an actuator 130, such as a handle, that is configured to generate a drive force to rotate the shaft 125. The actuator 130 can also be configured to receive a feedback force. In further detail, and in some embodiments, the system 100 includes a distal portion 105 designed and constructed to deliver a drive force generated by the actuator 130. The drive force can be a rotational force or a torque. For example, in the context of a hernia mesh fixation surgery, the drive force can be used to insert a fastener into tissue. The fastener may be inserted in a rotational manner. The distal portion 105 may include a coupling mechanism to temporarily hold a member during delivery. In various embodiments, the distal portion may include any component configured to deliver a force externally. In some embodiments, delivering a drive force by the distal portion 105 may correspond to a predetermined number of rotations. For example, properly inserting a fastener may require a predetermined number of rotations (e.g., 9 rotations). Further, this number of rotations may correspond to a fixed number or degree of actuation by the actuator 130. By adjusting properties associated with the frictional element and frictional disk (e.g., diameters of associated gears, coefficients of friction, lever arm lengths, etc.), the system 100 may be configured to adjust the amplification without altering the predetermined number of rotations at the distal portion 105 and actuations at the actuator 130.

In some embodiments, the system 100 includes a force transmission device 110 designed and constructed to convey, transmit or otherwise mechanically transfer a force from the actuator 130 to the distal portion 105, as well as transfer a resistive force from the distal portion 105 back to the actuator 130. In some embodiments, the force transmission device 110 includes a rotational force transmission device, such as a shaft that is configured to rotate about a central axis. In some embodiments, the force transmission device 1 10 includes a lateral force transmission device such as a spring loaded force transmission device. In some embodiments, the force transmission device 100 includes a complex force transmission device that employs a combination of rotational and lateral force transmission techniques. The force transmission device 1 10 may be coupled to the distal portion 105 and the frictional element 115 or the frictional disk 120. The force transmission device 110 may be directly coupled to the frictional element 1 15, or coupled via one or more other components (such as, e.g., gears, pinion gears, bevel gears, fasteners, etc.).

In some embodiments, the system 100 includes a frictional element 115. The frictional element 115 can include any frictional element having a desired coefficient of friction and designed and constructed to transfer a normal force to a frictional disk 120. As the normal force on the frictional element 115 increases, the force due to friction increases. Thus, the frictional force can be proportional to the product of the coefficient of friction between the frictional element 1 15 and the frictional disk 120 and the normal force (which corresponds to the resistive force generated at the distal portion 105).

In some embodiments, the frictional element 1 15 may include a metal bar with a frictional coefficient. In some embodiments, the coefficient of friction can range from about 0.2 to about 1.5. The frictional element 1 15 can include any type of metal or material, including, e.g., stainless steel, titanium, tungsten carbide, gold, silver, platinum, plastic, glass, metal alloys, or any other material that can facilitate force feedback. In some embodiments, the frictional element 115 can be modified to adjust a coefficient of friction. For example, the frictional element 1 15 can be smoothened in order to decrease a coefficient of friction, thus decreasing the amount of force feedback amplification. In another example, the frictional element 115 can be made rougher by abrasion in order to increase the coefficient of friction, thus increasing the force feedback amplification.

In some embodiments, the system 100 includes a frictional disk 120. The frictional disk 120 can be designed and constructed to spin about a central axis (e.g., an axis in the center of the frictional disk or another point within the circumference of the central disk such that the frictional disk 120 spins or rotates). The frictional disk 120 may be coupled to one or more gears that facilitate rotating the frictional disk. In some embodiments, the frictional disk 120 may further be configured to rotate about an axis external to the frictional disk 120, such as a shaft 125 or other lever arm. The frictional disk 120 may include any type of material including, e.g., stainless steel, titanium, tungsten carbide, gold, silver, platinum, plastic, glass, metal alloys, or any other material that can facilitate force feedback. In some embodiments, the frictional disk 125 may be the same material as the frictional element 115, while in some embodiments the frictional disk 125 is a different material than the frictional element 1 15. In some embodiments, the coefficient of friction of the frictional disk 125 can range from about 0.2 to about 1.5. In some embodiments, the frictional disk 125 can be circular in shape and include a diameter. The diameter can vary based on the application or desired amount of force feedback amplification.

In some embodiments, the system 100 includes a shaft 125 that is configured to convey, transmit, or otherwise mechanically transfer a drive force generated by the actuator 130 to the frictional disk 120, and convey, transmit, or otherwise mechanically transfer resistive force generated at the distal portion back to the actuator 130. The shaft 125 can include a length and include any type of material including, e.g., stainless steel, titanium, tungsten carbide, gold, silver, platinum, plastic, glass, metal alloys, or any other material that can facilitate force feedback. The shaft 125 can be designed and constructed to rotate or otherwise transmit the force. For example, the shaft 125 can rotate about a central axis responsive to actuation of the actuator 130. The shaft 130 may be coupled to the frictional disk 120 and the actuator 130. The shaft may be directly coupled to the frictional disk 120 and the actuator 130, or coupled via one or more other components (such as, e.g., gears, pinion gears, bevel gears, fasteners, etc.).

In some implementations, the system 100 includes an actuator 130 designed and constructed to generate a drive force and receive a feedback force. In some embodiments, the actuator 130 includes a handle. In some embodiments, the actuator 130 includes a rack and pinion configuration. In some embodiments, the actuator includes a pneumatic mechanism to deliver force. In some embodiments, the actuator 130 is coupled to the shaft 125 via one or more components such as gears, bevel gears, pinion gears, etc. The actuator 130 can include any type of material including, e.g., stainless steel, titanium, tungsten carbide, gold, silver, platinum, plastic, glass, metal alloys, or any other material that can facilitate force feedback. In some embodiments, the actuator 130 can be handheld and designed and constructed to be operated by a human in a surgical and sterile environment.

Upon actuation of the actuator 130, system 100 can provide force feedback by dissipating energy via the frictional element 115 and frictional disk 120. In some

embodiments, upon actuation of the actuator 130, the actuator drives the actuation of the shaft 125 proximate to the actuator 130. In addition, actuation of the actuator 130 moves the frictional disk 120 such that it pushes against a frictional element 1 15, thus generating a frictional force that increases as the force seen during delivery increases (e.g., the resistive force generated at the distal portion 105). As the force of friction increases between the frictional disk 120 and frictional element 1 15, a moment is transferred through, e.g., gears or belts, to the actuator 130, making it harder to actuate the actuator (e.g., depress a handle), thereby amplifying a force at the distal portion 105. Various designs may use this concept. The designs can vary based on the types of actuation (e.g., rotational, translational, or complex).

FIG. 2 is an illustration of one embodiment of an example apparatus 200 for providing force feedback. In brief overview, the apparatus 200 includes a proximal shaft 125. The apparatus 200 can include a lever arm 215. The lever arm 215 can include a first portion that is on the proximal shaft 125 and a distal portion that is away from the proximal shaft 125. The apparatus 200 can include a frictional disk 120 that is coupled to the distal portion of the lever arm 215. The apparatus 200 can include a frictional element 115 that is on a distal shaft 105 and configured to push against the frictional disk 120 (or the frictional disk 120 is configured to push against the frictional element 1 15). The apparatus 200 can include a first gear 205 that meshes or engages with a second gear 210. The first gear 205 can facilitate the rotation and spinning of the frictional disk 120. The apparatus 200 can include a distal shaft 105 that delivers a drive force received via the proximal shaft 125. For example, the frictional disk 120 can push against the frictional element 1 15. The frictional element 115, which is coupled to the distal shaft 105, can rotate the distal portion 105 as the frictional disk 120 pushes against the frictional element 115. The distal shaft 105 can also receive a resistive force. Each component of the apparatus 200 can include any type of material including, e.g., stainless steel, titanium, tungsten carbide, gold, silver, platinum, plastic, glass, metal alloys, or any other material that can facilitate force feedback.

Components of the apparatus 200 can include the same material or different materials.

In further detail, and in some embodiments, the apparatus 200 includes a proximal shaft 125. The proximal shaft 125 can be coupled to an actuator 130. The proximal shaft 125 can transmit a drive force received from the actuator 130. In some embodiments, the proximal shaft 125 can include a cylindrical shape with a length and a radius. In some embodiments, the proximal shaft 125 can include a rectangular shape with a depth, length and height. In some embodiments, the proximal shaft 125 can include an hexagonal, octagonal, or other n-sided shape with a corresponding length, depth, and height and other dimensions corresponding to the shape. The apparatus 200 can include a lever arm 215 having a first portion that is on the proximal shaft 125 and a second portion that is away from the proximal shaft 125. The first and second portions of the lever arm may be separated by a separation distance 220. The lever arm 215 can coupled to the proximal shaft 125 such that the lever arm 215 can rotate about the proximal shaft 125. During rotation, the separation distance 215 remains constant. In some embodiments, the apparatus 200 includes a frictional disk 120 designed and constructed to push against a frictional element 1 15 responsive to rotation force applied to the proximal shaft 125 via an actuator 130. The frictional disk 120 can be coupled directly to the lever arm 215 or coupled via a shaft or other component such that the frictional disk 120 can orbit or move around in a circular motion about an axis of the proximal shaft 125. The frictional disk 120 can be coupled to a second portion of the lever arm 215 that is at a distal end from the proximal shaft 125. In some embodiments, the frictional disk 120 can be circular in shape and include a radius and thickness. The radius of the frictional disk 120 may correspond to a desired amplification factor. The frictional disk 120 may be designed and constructed such that it has a center of gravity at a central axis that is in the center of the frictional disk 120, which corresponds to where the frictional disk 120 is coupled to the lever arm 215. The frictional disk 120 may include holes, slots, protrusions, or other features. For example, the frictional disk 120 may include smaller circular holes that form a concentric circle around a central axis of the frictional disk 120. The number and placement of the holes may maintain structural rigidity of the frictional disk and a center of gravity at a central axis of the frictional disk, while also reducing the overall weight of the frictional disk.

In some embodiments, the apparatus 200 includes a frictional element 1 15 designed and constructed to push against the frictional disk 120 in order to convey a normal force. In some embodiments, the frictional element 1 15 can include a frictional bar. The frictional element 115 can include a first portion that is on a distal shaft 105, and a second portion that is at a distal end from the distal shaft 105. The second portion of the frictional element 1 15 may touch the frictional disk 120. The frictional element 1 15 may be coupled to the distal shaft 105 such that the frictional element 1 15 can rotate the distal shaft 105 and such that the normal force applied by the frictional element 115 to the frictional disk 120 increases as the resistive force at the distal shaft 105 increases. Accordingly, as the resistive force at the distal shaft 105 decreases, the normal force applied by the frictional element 115 to the frictional disk 120 may also decrease. In various embodiments, the frictional element 115 may be any shape that facilitates applying a normal force to the frictional disk 120 including, e.g., a rectangular, cylindrical, hexagonal, octagonal, other or n-sided shape. In some embodiments, the frictional element 115 can include holes, slots, protrusions, or other features. For example, the frictional element 1 15 can include a hole at the distal portion of the frictional element. The hole may serve to reduce the weight of the frictional element, while maintaining the structural rigidity of the frictional element 1 15. In some embodiments, the apparatus 200 includes a distal shaft 105. The distal shaft 105 can receive a drive force from the proximal shaft 125 via the frictional element 115. In some embodiments, the distal shaft 105 is not directly coupled to the proximal shaft 125. Rather, the proximal shaft 125 is driven by an actuator and the distal shaft 105 is driven via the feedback system, such as the frictional disk 120 and frictional element 1 15. For example, the frictional disk 120 and lever arm 215 are rotated and spun by the proximal shaft 125 and actuator, and the distal shaft 105 is rotated by the movement of the frictional element 115.

In some embodiments, the distal shaft 105 can include a cylindrical shape with a length and a radius. In some embodiments, the distal shaft 105 can include a rectangular shape with a depth, length and height. In some embodiments, the distal shaft 105 can include an hexagonal, octagonal, or other n-sided shape with a corresponding length, depth, and height and other dimensions corresponding to the shape. In some embodiments, the distal shaft 105 can include a connection to various other components or a work load (e.g., a fastener that is to be inserted into tissue). In some embodiments, the apparatus 200 includes a first gear 205 and a second gear

210. In some embodiments, the first gear 205 can be coupled to the frictional disk 120 and configured to rotate the frictional disk 120 about the axis of the frictional disk 120. The first and second gear 205 and 210 can include a plurality of teeth that mesh with or engage with each other. The second gear 210 can be rotationally fixed such that the first gear 205 orbits about the second gear 210. In some embodiments, the second gear 210 is rotationally fixed relative to the frictional element 1 15. The first and second gears 205 and 210 can have the same or different diameters and thicknesses. In some embodiments, the first and second gears 205 and 210 may include pinion gears, annular gears, bevel gears, belts or any other type of gear that facilitates force feedback amplification. In operation, when the proximal shaft 125 rotates, the torque seen at the distal shaft

105 is amplified at the proximal shaft 125. That is, the apparatus 200 amplifies a rotational force seen at the distal shaft 105 as opposed to a translational force seen at the distal shaft 105. The apparatus 200 utilizes the spinning frictional disk 120 on the lever arm 1 15 that is driven by the actuator 130. The frictional disk 120 pushes against the frictional element 1 15 that is attached to the distal shaft 105, thus rotating the distal shaft 105. As the proximal shaft 125 spins, the attached lever arm 215 also spins. This lever arm 215 moves the frictional disk 120 around in a circle or orbit. The frictional disk 120 also spins relative to its own axis because it has an attached first gear 205 that meshes with a second gear 210 that is rotationally fixed. As the frictional disk 120 spins around the proximal shaft 125 as well is its own axis, the frictional disk 120 pushes the frictional element 1 15, which rotates the distal shaft 105. The apparatus 200 is configured to amplify force by amplifying the normal force seen at the frictional disk 120, which may correspond to a rotational or resistive force seen at the distal shaft 105. An increase in the rotational force increases the normal force at the frictional element 115, thus resulting in force amplification. For example, the increased normal force can account for an increased frictional force. By preventing the frictional disk 120 from spinning as easily, a larger force may be required to actuate the actuator 130.

Forces are also amplified because they are being applied at a distance from the proximal shaft 125, e.g., the separation distance 220. The further the forces are applied from the proximal shaft 125, the more they are amplified.

In some implementations, one or more components (e.g., frictional disk and frictional element) of apparatus 300 may undergo frictional wear as particles from materials rub against each other. In some applications, this may not be an issue, while in other applications (e.g., a medical device), these particles can cause adverse effects if they migrate through the device and into the body of a patient. The frictional wear of metal on metal may be directly proportional to the sliding distance and an applied load. The wear volume may be determined using the following equation: W = KsPI p_m , where ^ is the wear volume, K is a constant related to the probability per unit encounter of production of a wear palticle, s is the sliding distance, P is the applied load, and p_m is the flow pressure of the softer material. The sliding distance s may be determined based on the circumference of the frictional disk and the number of rotations expected per use of the apparatus 300 (e.g., 9 rotations per actuation of mesh fixation apparatus to apply a fastener). To prevent wear particles from entering undesired areas, in some embodiments, the frictional disk and frictional element may be enclosed. The enclosure may be configured to allow the apparatus 300 to function properly, while trapping any wear particles from the frictional disk and frictional element.

FIG. 3 is an illustration of one embodiment of an example apparatus 300 for providing force feedback. In some embodiments, the apparatus 300 may be substantially similar to apparatus 200. However, apparatus 300 includes an actuator 305 configured to rotate or spin the proximal shaft 125. In some embodiments, the actuator 300 includes a handle 330 that includes a rack 325 that includes a plurality of teeth that engage with a pinion gear 320. When the handle 330 is depressed or actuated, the rack 325 moves and engage with the pinion gear 320, thus rotating the pinion gear 320. The pinion gear 320 is fixed to a bevel gear 310, which rotates the proximal shaft 125 through the second bevel gear 315. As the force is amplified by the frictional disk 120 and frictional element 1 15, the handle 330 may be harder to actuate or depress, thus providing force feedback to a user of the actuator 305.

FIG. 4 is an illustration of a block diagram 400 for calculating an amplification factor for one embodiment of an apparatus for providing force feedback. In brief overview, the block diagram 400 includes parameters associated with a frictional disk 405 (e.g., frictional disk 120), a pinion gear 410 (e.g., gear 205), and a distal shaft 415 (e.g., shaft 105).

Additional parameters identified in Table 1 below can be used to calculate the amplification factor. To determine the amplification, the amplification calculator receives an input torque "T" (e.g., a torque seen at the distal shaft such as a torque needed to drive a fastener), a shaft radius of the lever arm, "Rs", the kinetic coefficient of friction between the frictional elements (e.g., the frictional disk 120 and the frictional element 1 15), the diameter of the frictional disk, Df, the diameter of the gear attached to the disk, Dp, and an added distance between the lever arm shaft and the distal shaft or the proximal shaft so that there is room for the system to spin, h. Each set of inputs will yield a resultant torque based on the equations in Table 1. Using the Amplification Calculator, the inputs can be changed to achieve a desired amplification.

The force amplification system not only amplifies the force of insertion, but it also amplifies the force it takes to deliver a fastener without insertion. To provide a noticeable feedback force to an actuator or handle, the torque to deliver a fastener without insertion forces may not be excessively higher than the torque of insertion.

Table 1 : Force Amplification Calculator with illustrative values

Table 1 describes the equations and input values used to calculate an amplification factor, which, for example, is T'/T = 0.5263/0.3 = 1.7543. Some or all input values may be used to calculate the amplification factor, while other inputs may be relevant to only some embodiments of the force feedback systems. Any other input values can be used to design a system with a different amplification factor. This system, and consequently calculator, can be implemented into any current or future product on the market that uses rotational motion to install a fastener.

The Amplification Calculator, however, may require additional input values of the actuator in order to calculate the torques and forces all the way to the handle of the user. To compute these values, more information about the actuator is needed. In an illustrative example, such as the threaded rotator actuator 305 shown in FIG. 3, the gear system, from handle to shaft, has its own amplification factor. This factor could be greater or less than I , depending on if there is a mechanical advantage or disadvantage present. For example, if the rotator needs to spin a certain number of times to deliver a fastener (e.g., 9 times), a mechanical disadvantage may be present. This means that the force for deployment is already being multiplied to the handle. Table 2 includes illustrative values for the amplification system. While the frictional coefficient is 0.45 in this example, materials with other frictional coefficients can be used and if the amplification is not high enough, the material can be made rougher by abrasion. Or if the amplification is too high enough, the metal can be sanded smooth, polished, or lubricated.

Table 2: Illustrative Input Values for Force Amplification

FIG. 5 is an illustration of one embodiment of a method for providing force feedback in a sterile environment. The method 500 can include rotating, by an actuator coupled to a lever arm via a proximal shaft, the proximal shaft (505). The method 500 can include rotating, via a first gear coupled to a frictional disk, the frictional disk about the proximal shaft and about an axis of the frictional disk (510). The frictional disk can be coupled to a distal portion of the lever arm, and an axis of the frictional can be disk separated from the proximal shaft by a separation distance. The method 500 can include engaging a second gear with the first gear (515). The method 500 can include generating, by a frictional element coupled to a distal shaft, responsive to actuation of the actuator, friction between the frictional element and the frictional disk as the frictional disk orbits about the second gear and rotates about its own axis (520). The frictional disk can push against the frictional element, thus rotating the distal shaft which may be rotationally fixed to the frictional element. The method 500 can include generating an amplified force that is an amplification of a force at the distal shaft (525).

FIG. 6 is a block diagram illustrating a general architecture for a computer system that may be employed to implement various elements of the systems and methods described herein, in accordance with an embodiment. In some embodiments, computer system 600 may be employed to implement one or more aspects of the amplification calculator of Table 1 as described in relation to FIG. 4. For example, some or all of Table 1 can be stored in a data structure in memory element 605. Upon receiving input via the input device 630, processor 610 can access the data structure stored in memory element 605 and execute, perform, or otherwise determine one or more value shown in Table 1 using one or more equations shown in Table 1. In some embodiments, the processor 610 may determine a resulting amplification value or amplification factor and output this information via a display 635 or other networked device.

In some embodiments, the processor 610 may prompt or otherwise request a user of the computer system 600 to provide additional information to facilitate computing an amplification factor. In some embodiments, the computer system 600 may be configured to receive a desired amplification factor and compute one or more other values of Table 1 in order to facilitate designing a force feedback system in accordance with one or more embodiment. For example, a user may desire to design a system and provide, as input, the amplification factor and coefficient of friction. Using this information, the processor 610 can access the memory element 605 storing a data structure comprising some or all the equations of Table 1 in order to compute the various parameters including, e.g., a radius, length, shaft separation, separation distance, etc.

The computing system 600 includes a bus 605 or other communication component for communicating information and a processor 610 or processing circuit coupled to the bus 605 for processing information. The computing system 600 can also include one or more processors 610 or processing circuits coupled to the bus for processing information. The computing system 600 also includes main memory 615, such as a random access memory (RAM) or other dynamic storage device, coupled to the bus 605 for storing information, and instructions to be executed by the processor 610. Main memory 615 can also be used for storing position information, temporary variables, or other intermediate information during execution of instructions by the processor 610. The computing system 600 may further include a read only memory (ROM) 620 or other static storage device coupled to the bus 605 for storing static information and instructions for the processor 610. A storage device 625, such as a solid state device, magnetic disk or optical disk, is coupled to the bus 605 for persistently storing information and instructions.

The computing system 600 may be coupled via the bus 605 to a display 635, such as a liquid crystal display, or active matrix display, for displaying information to a user. An input device 630, such as a keyboard including alphanumeric and other keys, may be coupled to the bus 605 for communicating information and command selections to the processor 610. In another implementation, the input device 630 has a touch screen display 635. The input device 630 can include a cursor control, such as a mouse, a trackball, or cursor direction keys, for communicating direction information and command selections to the processor 610 and for controlling cursor movement on the display 635.

According to various implementations, the processes described herein can be implemented by the computing system 600 in response to the processor 610 executing an arrangement of instructions contained in main memory 615. Such instructions can be read into main memory 615 from another computer-readable medium, such as the storage device 625. Execution of the arrangement of instructions contained in main memory 615 causes the computing system 600 to perform the illustrative processes described herein. One or more processors in a multi-processing arrangement may also be employed to execute the instructions contained in main memory 615. In alternative implementations, hard-wired circuitry may be used in place of or in combination with software instructions to effect illustrative implementations. Thus, implementations are not limited to any specific combination of hardware circuitry and software.

Although an example computing system has been described in FIG. 6,

implementations of the subject matter and the functional operations described in this specification can be implemented in other types of digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them.

Implementations of the subject matter and the operations described in this specification can be implemented in digital electronic circuitry, or in computer software, firmware, or hardware, including the structures disclosed in this specification and their structural equivalents, or in combinations of one or more of them. The subject matter described in this specification can be implemented as one or more computer programs, i.e., one or more circuits of computer program instructions, encoded on one or more computer storage media for execution by, or to control the operation of, data processing apparatus. Alternatively or in addition, the program instructions can be encoded on an artificially generated propagated signal, e.g., a machine-generated electrical, optical, or electromagnetic signal that is generated to encode information for transmission to suitable receiver apparatus for execution by a data processing apparatus. A computer storage medium can be, or be included in, a computer-readable storage device, a computer-readable storage substrate, a random or serial access memory array or device, or a combination of one or more of them. Moreover, while a computer storage medium is not a propagated signal, a computer storage medium can be a source or destination of computer program instructions encoded in an artificially generated propagated signal. The computer storage medium can also be, or be included in, one or more separate components or media (e.g., multiple CDs, disks, or other storage devices).

The term "data processing apparatus" or "computing device" encompasses various apparatuses, devices, and machines for processing data, including by way of example a programmable processor, a computer, a system on a chip, or multiple ones, or combinations of the foregoing. The apparatus can include special purpose logic circuitry, e.g., an FPGA (field programmable gate array) or an ASIC (application specific integrated circuit). The apparatus can also include, in addition to hardware, code that creates an execution environment for the computer program in question, e.g., code that constitutes processor firmware, a protocol stack, a database management system, an operating system, a cross- platform runtime environment, a virtual machine, or a combination of one or more of them. The apparatus and execution environment can realize various different computing model infrastructures, such as web services, distributed computing and grid computing

infrastructures.

A computer program (also known as a program, software, software application, script, or code) can be written in any form of programming language, including compiled or interpreted languages, declarative or procedural languages, and it can be deployed in any form, including as a stand-alone program or as a circuit, component, subroutine, object, or other unit suitable for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program can be stored in a portion of a file that holds other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordinated files (e.g., files that store one or more circuits, sub programs, or portions of code). A computer program can be deployed to be executed on one computer or on multiple computers that are located at one site or distributed across multiple sites and interconnected by a communication network. Processors suitable for the execution of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read only memory or a random access memory or both. The essential elements of a computer are a processor for performing actions in accordance with instructions and one or more memory devices for storing instructions and data. Generally, a computer will also include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto optical disks, or optical disks. However, a computer need not have such devices. Moreover, a computer can be embedded in another device, e.g., a mobile telephone, a personal digital assistant (PDA), a mobile audio or video player, a game console, a Global Positioning System (GPS) receiver, or a portable storage device (e.g., a universal serial bus (USB) flash drive), to name just a few. Devices suitable for storing computer program instructions and data include all forms of non-volatile memory, media and memory devices, including by way of example

semiconductor memory devices, e.g., EPROM, EEPROM, and flash memory devices;

magnetic disks, e.g., internal hard disks or removable disks; magneto optical disks; and CD ROM and DVD-ROM disks. The processor and the memory can be supplemented by, or incorporated in, special purpose logic circuitry.

To provide for interaction with a user, implementations of the subject matter described in this specification can be implemented on a computer having a display device, e.g., a CRT (cathode ray tube) or LCD (liquid crystal display) monitor, for displaying information to the user and a keyboard and a pointing device, e.g., a mouse or a trackball, by which the user can provide input to the computer. Other kinds of devices can be used to provide for interaction with a user as well; for example, feedback provided to the user can be any form of sensory feedback, e.g., visual feedback, auditory feedback, or tactile feedback; and input from the user can be received in any form, including acoustic, speech, or tactile input.

While this specification contains many specific implementation details, these should not be construed as limitations on the scope of any inventions or of what may be claimed, but rather as descriptions of features specific to particular implementations of particular inventions. Certain features described in this specification in the context of separate embodiments can also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment can also be implemented in multiple embodiments separately or in any suitable subcombination. Moreover, although features may be described above as acting in certain combinations and even initially claimed as such, one or more features from a claimed combination can in some cases be excised from the combination, and the claimed combination may be directed to a subcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Moreover, the separation of various system components in the embodiments described above should not be understood as requiring such separation in all embodiments, and it should be understood that the described program components and systems can generally be integrated in a single software product or packaged into multiple software products.

References to "or" may be construed as inclusive so that any terms described using "or" may indicate any of a single, more than one, and all of the described terms.

Thus, particular embodiments of the subject matter have been described. Other embodiments are within the scope of the following claims. In some cases, the actions recited in the claims can be performed in a different order and still achieve desirable results. In addition, the processes depicted in the accompanying figures do not necessarily require the particular order shown, or sequential order, to achieve desirable results.

Claims

What is claimed is:

1. An apparatus for providing force feedback, comprising:

an actuator coupled to a lever arm via a proximal shaft, the actuator configured to rotate the proximal shaft;

a frictional disk coupled to a distal portion of the lever arm, an axis of the frictional disk separated from the proximal shaft by a separation distance;

a first gear coupled to the frictional disk and configured to rotate the frictional disk about the axis of the frictional disk;

a second gear that meshes with the first gear, the second gear configured to rotate the frictional disk about the proximal shaft; and

a frictional element coupled to a distal shaft and configured to generate friction between the frictional element and the frictional disk, the frictional element configured to rotate the distal shaft;

wherein upon actuation of the actuator, the frictional element generates friction between the frictional element and the frictional disk as the frictional disk orbits about the proximal shaft and spins about its own axis.

2. The apparatus of claim 1, wherein the second gear is rotationally fixed.

3. The apparatus of claim 1, wherein the frictional disk is further configured to push against the frictional element as the frictional disk orbits about the proximal shaft.

4. The apparatus of claim 1 , wherein an amplified force is observed at the actuator.

5. The apparatus of claim 4, wherein the amplified force corresponds to a coefficient of friction between the frictional disk and the frictional element, a shaft radius of the lever arm, a first diameter of the first gear, a second diameter of the second gear, and the separation distance between the axis of the frictional disk and the proximal shaft.

6. The apparatus of claim 1, wherein an amplified force observed at the actuator is proportional to the separation distance between the axis of the frictional disk and the proximal shaft.

7. The apparatus of claim 1, wherein an amplified force is proportional to a sum of a force of the first gear and a force corresponding to a normal force on torque at a distal end of the distal shaft.

8. The apparatus of claim 7, wherein the force of the first gear is proportional to a frictional force on the frictional disk, proportional to a radius of the frictional disk, and inversely proportional to a radius of the first gear.

9. The apparatus of claim 1, wherein each component of the apparatus is configured to be sterilized.

10. The apparatus of claim 1, wherein the actuator comprises:

a handle with a rack configured to drive a pinion gear; and

a bevel gear coupled to the proximal shaft, the bevel gear engaging with the pinion gear,

wherein actuation of the actuator rotates the pinion gear, the bevel gear, the proximal shaft.

11. A hernia mesh fixation device comprising:

an actuator coupled to a lever arm via a proximal shaft, comprising:

a handle with a rack configured to drive a pinion gear; and

a bevel gear coupled to the proximal shaft, the bevel gear fixed to the pinion gear,

a first gear coupled to the frictional disk and configured to orbit the frictional disk about the proximal shaft and allow the frictional disk to rotate about the axis of the frictional disk;

a second gear that meshes with the first gear and is rotationally fixed; and a frictional element coupled to a distal shaft and configured to generate friction between the frictional element and the frictional disk, the frictional element configured to rotate the distal shaft.

12. The device of claim 11, wherein upon actuation of the actuator, the frictional element applies friction to the frictional disk as the frictional disk orbits about the proximal shaft and rotates about its own axis.

13. The device of claim 11, wherein the pinion gear and the bevel gear are coupled to the proximal shaft.

14. The device of claim 11, wherein the actuator provides an amplification factor.

15. A method for providing force feedback in a sterile environment, comprising:

rotating, by an actuator coupled to a lever arm via a proximal shaft, the proximal shaft;

orbiting and rotating, via a first gear coupled to a frictional disk, the frictional disk about the proximal shaft and about an axis of the frictional disk, respectively, the frictional disk coupled to a distal portion of the lever arm, an axis of the frictional disk separated from the proximal shaft by a separation distance;

engaging, by the first gear, a second gear;

generating, by a frictional element coupled to a distal shaft, responsive to actuation of the actuator, friction between the frictional element and the frictional disk as the frictional disk orbits about the second gear and rotates about its own axis; and

generating an amplified force that is an amplification of a force at a distal shaft.

16. The method of claim 15, further comprising:

dissipating energy based on a coefficient of friction between the frictional disk and the frictional element.

17. The method of claim 15, wherein the amplified force is proportional to the separation distance between the axis of the frictional disk and the proximal shaft.

18. The method of claim 15, wherein the amplified force is proportional to a sum of a force of the first gear and a force corresponding to a normal force on torque at the distal shaft.

19. The method of claim 18, wherein the force of the first gear is proportional to a frictional force on the frictional disk, proportional to a radius of the frictional disk, and inversely proportional to a radius of the first gear.

20. The method of claim 15, wherein each component used to generate the amplified force is sterilized.