KR20180065827A - Handheld tool for leveling uncoordinated motion - Google Patents

Abstract

A handheld tool includes a handle that a user grasps, an attachment arm extending from the handle that is configured to connect to a user-assistive device, a first inertial measurement unit (IMU) mounted to the attachment arm to acquire measurements of one or more of a motion or an orientation of the user-assistive device and to generate feedback data indicative of the measurements, an actuator assembly coupled to manipulate the user-assistive device via the attachment arm in at least two orthogonal dimensions, and a motion control system coupled to receive the feedback data from the first IMU and coupled to provide commands to the actuator assembly to provide auto-leveling of the user-assistive device to a frame of reference while the user manipulates the handheld tool. The auto-leveling functionality can help users who have uncoordinated muscle movements to have improved quality of life by providing greater independence and self-control over routine tasks.

Description

HANDHELD TOOL FOR LEVELING UNCOORDINATED MOTION BACKGROUND OF THE INVENTION [0001]

The present disclosure generally relates to a tool for leveling or stabilizing muscle motion.

Movement disorders refer to partial or total loss of body parts, usually limb function. This often occurs due to muscle weakness, poor physical fitness, or lack of exercise control. It is often a symptom of neurological disorders such as Parkinson's disease, ALS, stroke, multiple sclerosis, or cerebral palsy. There are few effective techniques that can be used to overcome movement disorders and exercise limits. As a result, many people have to rely on caregivers because they can not perform simple tasks such as eating themselves.

BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the invention, which are not intended to be limiting, are described with reference to the following drawings, wherein like reference numerals designate like parts throughout the various views unless otherwise indicated. The drawings are not necessarily drawn to scale, emphasis instead being placed upon illustrating the principles illustrated.
Figure 1A is a perspective view of a handheld tool that provides auto-leveling to a user-assisted device in accordance with an embodiment of the present disclosure.
1B is an exploded perspective view of a handheld tool that provides auto-leveling to a user-assisted device in accordance with an embodiment of the present disclosure.
1C is a top view illustration of a handheld tool that provides auto-leveling to a user-assisted device in accordance with an embodiment of the present disclosure.
1D is a side view illustration of a handheld tool that provides auto-leveling to a user-assisted device in accordance with an embodiment of the present disclosure.
2 is a functional block diagram illustrating components of a system circuit of a handheld tool that provides auto-leveling to a user-assisted device in accordance with an embodiment of the present disclosure.
3 is a functional block diagram illustrating components of a motion control system for providing a user-assisted device of a handheld tool with auto-leveling in accordance with an embodiment of the present disclosure.
Figure 4 is a perspective view of a handheld tool having a user-assisted device configured to hold a drinking cup according to an embodiment of the present disclosure.

Embodiments of devices, systems, and methods for providing auto-leveling of a user-assisted device of a handheld tool are described herein. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the embodiments. However, one of ordinary skill in the art will recognize that the techniques described herein may be practiced without one or more of the specific details, or with other methods, components, materials, and so on. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.

Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Moreover, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

Techniques have been developed to help overcome human tremor, but they may be unsuitable for a variety of situations where human tremors are either too extreme in their size, or in which movement disorders result in skewing or spill due to lack of muscle control have. Stabilized platforms using an inertial measurement unit (IMU) have been developed for cameras (eg, brushless gimbal controllers) in both military applications and for the hobbyists. A stabilized flight controller similarly stabilizes the moving platform in three-dimensional space. However, it is not feasible to integrate these solutions into small, lightweight handheld tools to help people with muscle strength or muscle control restrictions perform routine tasks such as eating, drinking, or otherwise. In addition, certain tasks (e. G., The surgical field) can benefit from tool leveling and / or stabilization in certain stressful environments such as operating rooms or even field hospitals.

Figures la-d illustrate a hand-held tool 105 that is capable of auto-leveling and, in some embodiments, stabilizing a user-assisted device 105 that is connected to an end of the handheld tool 100, in accordance with an embodiment of the present disclosure. (100). 1B is an exploded perspective view, FIG. 1C is a plan view, and FIG. 1D is a side view, all of which are the same implementations of the handheld tool 100. FIG. 1A is a perspective view of the handheld tool 100, Yes. The illustrated embodiment of the handheld tool 100 includes a user-assisted device 105, an attachment arm 110, an actuator assembly 115, a handle 120, and a system circuit. An illustrative embodiment of an actuator assembly 115 includes an actuator 125, an actuator 130, a link device 135, and a link device 140. The system circuit includes a leveling IMU 145, a motion control system 150, a power source 155, position sensors (not illustrated in Figures la-1d), a system controller 160, a system memory 165, (Not shown). In one embodiment, the handheld tool 100 may also include a tremor IMU 175.

The handheld tool 100 is an auto-leveling (and in some embodiments a tremor stabilized) platform that can be configured to hold a variety of different user-assist devices 105. The handheld tool 100 provides active leveling using electronic actuators and a feedback control system. 1a-d illustrate a user-assist device 105 as a spoon; However, the user-assist device 105 can be used to provide a variety of eating and drinking tools (e.g., see cup placement device 400 in FIG. 4), cosmetic devices, pointing devices, ), Or the like.

An illustrated embodiment of the handheld tool 100 includes a leveling IMU 145 disposed on an attachment arm 145 that includes a leveling IMU 145 that is positioned on a user-assisted device 145 to measure the movement and orientation of the user- (105). The leveling IMU 145 outputs feedback data indicative of the measured motion and orientation to the motion control system 150. The leveling IMU 145 may be implemented by a gyroscope and an accelerometer, or may even include a magnetometer. In one embodiment, the leveling IMU 145 is a solid state device.

In one embodiment, the motion control system 150 includes a leveling IMU 145 for linear accelerations, angular velocities, and orientations relative to a reference frame (e.g., a gravity vector) of the user-assist device 105 at a given instant ). The motion control system 150 then executes an algorithm for estimating the orientation of the user-assist device 105 in a three-dimensional (" 3D ") space relative to the reference frame. This estimated or estimated vector of gravity relative to the body-frame of the leveling IMU (and user-assisted device 105) is continuously updated in real time and also generates a command signal to drive and control the actuator assembly 115 in real time . In one embodiment, the command signal includes a roll command and a pitch command.

The actuator assembly 115 is connected to the user-assist device 105 for operating the user-assist device 105 in at least two orthogonal dimensions. In the illustrated embodiment, the two orthogonal dimensions include a rotation around the pitch axis 180 and a rotation about the roll axis 185. The pitch axis 180 is orthogonal to the roll axis 185 extending longitudinally through the handle 120. In other embodiments, the two motion dimensions need not be orthogonal. In addition, in other embodiments, additional degrees of freedom, such as linear motions or even yaw rotation, may be added to the actuator assembly 115.

Actuator assembly 115 may be used to move attachment arm 110 relative to handle 120 for auto-leveling and, in some embodiments, to stabilize vibration, and further to move user- Gt; handheld tool 100 < / RTI > If the user-assist device 105 is pitched or rolled relative to a fixed reference frame (e.g., gravity vector), the motion control system 150 commands the actuator assembly 115 to compensate for the level orientation and maintain Assist device 105 to move in opposite directions to provide offset orientation to counteract, or even counter, tremors. The overall effect is that the user-assisted device 105 remains in a fixed (or even stabilized) state in orientation, regardless of how the handle is oriented within the physical limits of the actuator assembly 115.

An illustrated embodiment of the actuator assembly 115 includes an actuator 125 that provides a rotational motion output about a roll axis 185. This roll motion is coupled to the actuator 130 via the link device 135 to cause the actuator 125 to physically rotate the actuator 130 about the roll axis 185. The illustrated embodiment of the actuator 130 provides rotational motion output about the pitch axis 180. The pitch and roll movements are coupled to the attachment arm and further to the user-assist device 105 via the linkage device 140 such that the actuator 130 rotates the user-assist device 105 while the actuator 125 is rolling the user- - Pitch auxiliary device (105). These orthogonal rotational movements are independently controlled.

In one embodiment, the handheld tool 100 includes two position sensors (not shown) that provide position information feedback to the motion control system 150 indicating rotational positions of outputs of the actuators 125 and 130 relative to the handle 120 . In other words, the position sensors represent the positions of the link devices 135 and 140 relative to the handle 120. In one embodiment, each position sensor is a Hall-effect sensor that monitors the positions of the link devices 135 or 140, respectively. Other position sensors including potentiometers, encoders, etc. may be implemented.

Conventional stabilization devices have attempted to provide stabilization using a weighted pendulum. However, a large mass is required to force the platform to remain in the leveling state. Disadvantages of such an implementation include the required volume and mass and the possibility of vibration and vibration of the pendulum at its natural frequency. The set-point (stabilized position) of the user-assisted device is also limited by the mechanical assembly and can not be easily adjusted. In addition, data about the user can not be collected by such purely mechanical means. In contrast, the feedback control system used in the handheld tool 100 can achieve much greater performance with a significantly smaller form-factor. No heavy weight is required, and motion control system 150 can be specially tuned to cope with various unintended movements (e.g., tremor stabilization). In practice, the motion control system 150 is adapted to both respond to uncoordinated movements (low frequency) for auto-leveling and to respond to unintended movements (high frequencies) for stabilization of human tremors Can be programmed.

In addition, the system controller 160 monitors data regarding the severity of the user's condition (e.g., the ability to maintain level orientation, the amount of feedback control assistance needed, the amount of unintentional tremor movements, etc.) And stores this data in the log in the system memory 165 for the last output via the communication interface 170. The logs may be analyzed and provided to the medical personnel to diagnose and treat the user / patient condition. Active control provided by motion control system 150 may be further programmed to automatically adjust to small increments over time as part of a treatment plan. The treatment plan can be monitored using logs and can also be customized on a patient-by-patient basis by referencing the logs. For example, the amount of active leveling / stabilization can be incrementally reduced at a specified rate as a kind of therapy or training, and the results can be periodically monitored with reference to the log.

In one embodiment, the attachment arm 110 is implemented as a permanent secure connection to a single user- In other embodiments, the attachment arm 110 may facilitate non-permanent attachment to remove or replace the user-assist device 105. Using non-permanent attachment allows the user to insert or attach different types of user-assisted devices 105 to the handheld tool 100. For example, the user-assist device 105 may include a variety of different dietary or drinking tools (e.g., spoons, knives, forks, cup holders), personal hygiene tools (e.g., toothbrushes, (E. G., A laser pointer or stick pointer), or the like, as well as other devices (e. G., Cosmetic devices, combs). Auto-leveling (and selective tremor stabilization) functionality allows users with unregulated (and / or unintentional) muscle movements to have improved self-control over greater independence and routine tasks Can help. In addition, the handheld tool 100 may have a professional use to assist those who are not affected by unaltered and / or unintentional muscle movements.

2 is a functional block diagram illustrating functional components of the system circuit 200, in accordance with an embodiment of the present disclosure. The system circuit 200 describes exemplary functional control components for operation of the handheld tool 100. Illustrated embodiments of the system circuit 200 include a motion control system 205, a system memory 210, a system controller 215, a communication interface 220, a power source 225, a leveling IMU 230, (235), and a tremor IMU (240).

The motion control system 205 receives (e. G. Polls) feedback data from the leveling IMU 230 to determine the orientation and movement of the user-assisted device 105, as described above. This feedback data is analyzed using a control algorithm to generate commands to operate the actuator assembly 115. In one embodiment, the motion control system 205 is implemented as a digital signal processing ("DSP") circuit. In another embodiment, the motion control system 205 is software / firmware logic stored on the system memory 210 and running on the system controller 215. In one embodiment, the system controller 215 is implemented as a microprocessor and the system memory 210 is a non-volatile memory (e.g., flash memory). Other types of memory and controllers may be used.

In one embodiment, communication interface 220 is communicatively coupled to system controller 215 for outputting data (e.g., a usage log) stored in system memory 210. The communication interface 220 may be implemented as a wired or wireless interface, such as a universal serial port (USB), a wireless Bluetooth interface, a Wi-Fi interface, a cellular interface, or the like.

As previously mentioned, the leveling IMU 230 is arranged to monitor the orientation and movement of the user-assist device 105. In the illustrated embodiment of Figs. La-d, the leveling IMU 145 is disposed on the attachment arm 145. Fig. In an embodiment in which the user-assist device 105 is permanently secured to the handheld tool 100, the leveling IMU 230 may be rigidly mounted to the user-assist device 105 itself, 110 may be considered to be an extension of the user-assisted device 105. Leveling IMU 230 may be implemented as a solid-state sensor comprising one or more of an accelerometer, gyroscope, or magnetometer.

The position sensors 235 are relative sensors that measure the relative positions of the outputs of the actuator assembly 115 with respect to the handle 120. In one embodiment, the position sensors 235 are Hall-effect sensors that monitor the position of the outputs of the actuators 125 and 130 by measuring the positions of the link devices 135 and 140. The relative position information output by the position sensors 235 may be recorded in a log in the system memory 210 to determine how much autoleveling the user requires and thereby diagnose the severity and progression of a given user .

In one embodiment, the handheld tool 100 may be rigidly mounted on the handle 120 to further include a torsional IMU 240 for measuring the movement / orientation of the handle 100. [ The tremble feedback information obtained by tremble IMU 240 may also be recorded in a log file in system memory 210 to facilitate diagnosis and treatment of the user's condition. In some embodiments, feedback data from the leveling IMU 230 may be sufficient and even desirable for both auto-leveling and stabilization of the user-assisted device 100, Data can also be used for feedback stabilization.

In the illustrated embodiment, the functional components of the system circuit 200 are powered by a power supply 225. In one embodiment, the power source 225 is a secondary battery (e.g., a lithium ion battery) disposed within the handle 120 of the handheld tool 100. Many of the other functional components of the system circuit 200 may also be disposed within the handle 120 to provide a compact and user-friendly form factor. For example, in various embodiments, some or all of the motion control system 205, the system memory 210, the system controller 215, the communication interface 220, the power source 225, Is disposed within the handle 120. As illustrated in Figs. La-d, actuator 125 and link device 135 are disposed at least partially within handle 120. Fig.

3 is a functional block diagram illustrating the functional components of motion control system 300 for providing auto-leveling to user-assisted device 105 of handheld tool 100, in accordance with an embodiment of the present disclosure . Motion control system 300 is one possible implementation of motion control system 150 or 205. The motion control system 300 may be implemented as software logic / instructions, firmware logic / instructions, hardware logic, or a combination thereof. In one embodiment, the motion control system 300 is a DSP circuit.

The illustrated embodiment of the motion control system 300 includes a rotation vector module 305, a low pass filter (LPF) 310, a complementary filter module 315, an estimation vector module 320, an inverse kinematic module 325 ), And a motion controller (330). Motion control system 300 is coupled to receive feedback data from leveling IMU 335 and position sensors 340. The illustrated embodiment of the leveling IMU 335 includes a gyroscope 345 and an accelerometer 350.

During operation, the gyroscope 345 is for outputting the gyro data _G Δ On the other hand, the accelerometer 350 outputs the accelerometer data Δ _A. The gyro data? _G is used by the rotation vector module 305 to adjust the previous error vector S _{n -1} to generate the current error vector S _n . The current error vector S _n is then provided to the complementary filter module 315. The complementary filter module 315 adjusts the current error vector S _n by a low-pass filtered version Δ ' _A of the accelerometer data Δ _A to generate an adjusted error vector S' _n . The adjustment error vector S ' _n is looped back to the estimation vector module 320 where it is latched or temporarily stored and provided to the vector module 305 rotated as the previous error vector S _{n -1} for the next cycle of operation .

The adjusted error vector S ' _n represents the difference vector between the reference frame (e.g., gravity vector) and the vector representing the current position of the user-assisted device 105. For example, the vector representing the current position of the user-assist device 105 may be a normal vector extending from the surface on which the leveling IMU 145 is placed. Of course, other vector orientations may be used to describe the user-assist device 105.

The gyroscope 345 is a high-speed motion sensor that outputs angular velocity data quickly, but it suffers from excessive drift time. In contrast, accelerometer 350 is a slow sensor that outputs accurate readings used by complementary filter 315 to update the current error vector S _{n and} to cancel out any drift. The accelerometer data [Delta] _A is low-pass filtered to remove high frequency variations due to sudden movements such as tremor movements, which are less useful for low frequency auto-leveling functions.

The adjusted error vector S ' _n is then provided to the inverse kinematics module 325. The inverse kinematics module 325 takes the adjusted error vector S ' _n along with the current position information of the actuator assembly 115 and generates error signals (e.g., pitch error (s)) that define the position parameters of the actuators 125 and 130 And roll error) to obtain the desired position of the user-assist device 105. [ The use of kinematic equations is known in the field of robot control systems.

The error signals are then input to the motion controller 330, which determines how to implement the actual commands (e.g., pitch command and roll command) to control the actuator assembly 115. In one embodiment, the motion controller 330 is implemented as a proportional-integral-derivative (PID) controller. Motion controller 330 attempts to reduce the correction overshoot and vibration while reducing error signals (e.g., pitch error and roll error).

In the illustrated embodiment, the motion control system 300 also includes a high frequency path 360 for the accelerometer data [Delta] _A to reach the motion controller 330. [ The high frequency path 360 allows unfiltered high frequency accelerometer data [Delta] _A to be analyzed by the motion controller 330 to implement shake stability control.

Some of the functional logic / software described above is described in terms of computer software and hardware. The described techniques may constitute machine-executable instructions embodied in a tangible or non-volatile machine (e.g., computer) readable storage medium, which, when executed by the machine, cause the machine to perform the described operations It will cause. In addition, the processes may be embodied in hardware such as a specific integrated circuit (ASIC) or the like.

Type of machine-readable storage medium can be accessed by a machine (e.g., a computer, a network device, a personal digital assistant, a manufacturing tool, or any device with one or more processors, etc.) And includes any mechanism for providing (i.e., storing) information in non-transitory forms. For example, a machine-readable storage medium may be any type of storage medium such as a recordable / non-recordable medium (e.g., read only memory (ROM), random access memory (RAM), magnetic disk storage medium, optical storage medium, flash memory device, .

The foregoing description of the illustrated embodiments of the invention including those described in the abstract is intended to be exhaustive or is not intended to limit the invention to the precise forms disclosed. While specific embodiments of the invention and examples for the invention have been described herein for purposes of illustration, various modifications are possible within the scope of the invention as recognized by those skilled in the art.

These modifications may be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed as limiting the invention to the specific embodiments disclosed in the specification. Rather, the scope of the present invention should be determined entirely by the following claims, which are to be construed in accordance with established principles of claim interpretation.

Claims (21)

As a handheld tool:
A handle for a user to hold the handheld tool;
An attachment arm extending from said handle, said attachment arm being configured to be connected to a user-assist device;
A first inertial measurement unit (IMU) mounted to the attachment arm for obtaining one or more measurements of movement or orientation of the user-assisted device and generating feedback data indicative of the measurements;
An actuator assembly coupled to manipulate the user-assist device through the attachment arm in at least two dimensions; And
And to provide the actuator assembly with commands to receive the feedback data from the first IMU and to provide auto-leveling of the user-assisted device to a reference frame while the user is manipulating the handheld tool Motion control system
/ RTI > 2. The handheld tool of claim 1, wherein the actuator assembly is operable to manipulate the user-assist device about two rotational axes with respect to the handle. The actuator assembly of claim 2, wherein the actuator assembly comprises:
A first actuator for controlling the rolling motion of the attachment arm; And
And a second actuator for controlling a pitching motion of the attachment arm
Handheld tools. 4. The actuator assembly of claim 3, wherein the actuator assembly comprises:
A first link device for mechanically coupling the rolling motion output from the first actuator to the second actuator, the first actuator for rolling the attachment arm by rolling the second actuator through the first link device Combined; And
Further comprising a second link device mechanically coupling the pitching motion output from the second actuator to the attachment arm
Handheld tools. The method of claim 3,
A first position sensor coupled to monitor a first relative position of a first output of the first actuator; And
A second position sensor coupled to monitor a second relative position of a second output of the second actuator,
, ≪ / RTI >
The first and second position sensors are coupled to feedback the position information to the motion control system
Handheld tools. 6. The method of claim 5,
A system controller disposed within the handle and coupled to collect position information from the first and second position sensors and to log the position information; And
A communication interface coupled to the system controller for outputting the log from the handheld tool;
The handheld device further comprising: 3. The handheld tool of claim 2, wherein the motion control system is further coupled to the actuator assembly to manipulate the actuator assembly about the two rotational axes to provide human-assist device with human tremor stabilization. 2. The apparatus of claim 1, further comprising a power source coupled to power the actuator assembly and the motion control system, wherein at least a portion of the power source, the motion control system, Held tools. 2. The handheld tool of claim 1, wherein the user-assisted device comprises one of a meal tool or a drinking tool. 6. The handheld tool of claim 1, wherein the user-assisted device comprises one of a pointer device, a decorating tool, a personal hygiene tool, or a professional tool. The method according to claim 1,
A second IMU connected rigidly to the handle for measuring human tremor while the user is holding and using the handheld tool,
The handheld device further comprising: At least one machine-accessible storage medium for providing instructions,
Wherein the instructions, when executed by a handheld tool, cause the handheld tool to:
Measuring at least one of the movement or orientation of the user-assisted device mounted at the distal end of the hand held tool by the IMU;
Outputting feedback data from the IMU based on the measurement;
Monitoring the feedback data in real time by a motion control system at least partially disposed within a handle of the handheld tool; And
Controlling the actuator assembly by the motion control system, wherein the actuator assembly includes at least two orthogonal dimensions to provide auto-leveling of the user-assisted device relative to a reference frame while the user is manipulating the handheld tool Assisted device to perform operations comprising: < RTI ID = 0.0 >
At least one machine-accessible storage medium. 13. The at least one machine-accessible storage medium of claim 12, wherein the at least two orthogonal dimensions comprise two rotational axes including a pitch axis and a roll axis. 14. The method of claim 13, wherein controlling the actuator assembly by the motion control system to provide auto-
Generating an error vector representing a position deviation from the reference vector of the user-assisted device based on the reference frame;
Updating the error vector based on the feedback data output from the IMU; And
Generating a pitch command for manipulating the actuator assembly about the pitch axis based at least in part on the error vector and a roll command for manipulating the actuator assembly about the roll axis
At least one machine-accessible storage medium. 15. The system of claim 14, wherein the IMU comprises a gyroscope and an accelerometer, the feedback data comprising gyroscope feedback data and accelerometer feedback data, and wherein the actuator assembly is controlled by the motion control system to provide the auto- The controlling step is:
Updating the error vector by the gyroscope feedback data; And
Further comprising low pass filtering the accelerometer feedback data prior to updating the error vector with the accelerometer feedback data
At least one machine-accessible storage medium. 14. The method of claim 13, further comprising: when executed by the handheld tool,
Further comprising instructions for causing the motion assembly to perform additional operations including controlling the actuator assembly by the motion control system about the two rotation axes to provide human vibration stabilization of the user-assisted device
At least one machine-accessible storage medium. 17. The method of claim 16, wherein controlling the actuator assembly by the motion control system about the two rotational axes to provide human tremor stabilization comprises:
And using accelerometer feedback data output from the accelerometer of the IMU without low pass filtering the accelerometer feedback data to provide feedback control for human tremor stabilization
At least one machine-accessible storage medium. 14. The method of claim 13, further comprising: when executed by the handheld tool,
Collecting position information from one or more position sensors coupled to monitor positions of the actuator assembly relative to the two rotational axes;
Recording the location information in a log; And
Further comprising instructions for causing the computer to perform additional operations including communicating the log from the handheld tool via a communication interface
At least one machine-accessible storage medium. 13. The method of claim 12, further comprising: when executed by the handheld tool,
Adjusting the amount of auto-leveling of the user-assisted device provided by the actuator assembly over time as part of a training plan or treatment plan to treat the user, To provide additional instructions to cause
At least one machine-accessible storage medium. 20. The at least one machine-accessible storage medium of claim 19, wherein the amount of auto-leveling provided by the actuator assembly is reduced over time as part of the treatment plan. 13. The system of claim 12, wherein a power source is disposed within the handle of the handheld tool and is also coupled to power the actuator assembly and the motion control system, wherein the user-assist device includes either a meal tool or a cup holder At least one machine-accessible storage medium.

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