High amplitude tremor stabilization by a handheld tool

Systems and methods for tracking unintentional high amplitude muscle movements of a user and stabilizing a handheld tool are described. The method may include detecting motion of a housing of the handheld tool when manipulated by a user while the user is performing a task with a user-assistive device attached to an attachment arm of the handheld tool, and storing the detected motion in a memory of the handheld tool as motion data. Furthermore, the method may include controlling a first motion generating mechanism and a second motion generating mechanism by generating a first motion signal and a second motion signal that respectively drive the first motion generating mechanism in a first degree of freedom and the second motion generating mechanism in a second degree of freedom to stabilize motion of the user-assistive device attached to the attachment arm of the handheld tool.

TECHNICAL FIELD

This disclosure relates generally to unintentional muscle movements, and in particular but not exclusively, relates to tracking unintentional muscle movements of a user and stabilizing a handheld tool while it is being used by the user.

BACKGROUND INFORMATION

Movement disorders are often caused by chronic neurodegenerative diseases such as Parkinson's Disease (“PD”) and Essential Tremor (“ET”). Both of these conditions are currently incurable and cause unintentional muscle movements or human tremors—uncontrollable rhythmic oscillatory movements of the human body. In many cases human tremors can be severe enough to cause a significant degradation in quality of life, interfering with daily activities/tasks such as eating, drinking, or writing.

Currently, persons with chronic neurodegenerative diseases are typically medicated with drugs that vary in effectiveness. The alternative to pharmacological treatment is brain surgery, such as deep brain stimulation (DBS) surgery. Similar to pharmacological treatments, DBS surgery varies in its effectiveness while being invasive and dangerous. Both forms of treatment are therefore non-optimal for treating persons with chronic neurodegenerative diseases, especially with respect to performing daily activities.

DETAILED DESCRIPTION

Embodiments of an apparatus, system and process for tracking unintentional high amplitude muscle movements of a user while using a handheld tool and stabilizing the handheld tool while the handheld tool is used to perform an ordinary activity, are described herein. In the following description numerous specific details are set forth to provide a thorough understanding of the embodiments. One skilled in the relevant art will recognize, however, that the techniques described herein can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.

FIG. 1Aillustrates a handheld tool100that tracks unintentional high amplitude muscle movements and performs motion stabilization, in accordance with an embodiment of the disclosure. Handheld tool100is capable of detecting and compensating for unintentional high amplitude muscle movement (e.g. tremors). In one embodiment, the muscle movements are high amplitude when they occur in a range of approximately 1-2 centimeters about a central point of the handheld tool, although unintentional high amplitude muscle movements may be as large as 8-10 centimeters about a central point of the handheld tool. In the embodiments discussed herein, the handheld tool100tracks these unintentional high amplitude muscle movements, and stabilizes (i.e., centers) a position of implement106in spite of the unintentional high amplitude muscle movements while implement is being used by a user.

Accordingly, the illustrated embodiment of handheld tool100includes a tremor tracking module120for measuring and tracking user tremors, as well as two or more sensors (e.g., sensor122and124) for providing signals to the tremor tracking module120for compensating for those same tremors, as discussed herein. These subsystems may have distinct components, or share some components such as power systems, memory, and may even share one or more sensors.

Handheld tool100includes a housing106, which functions as a handle enabling a user to hold handheld tool100. Handheld tool100also includes an attachment arm104coupled to the housing106via motion generating mechanisms, as discussed in greater detail below. Attachment arm104is configured to accept an implement102(e.g., a user-assistive device, such as a spoon in the illustrated embodiment) to its end distal from housing106. In one embodiment, attachment arm104is integrated with a specific type of implement102(e.g., the spoon as illustrated). In other embodiments, attachment arm104can receive a variety of different implements102in a variety of ways including but not limited to a friction, snap, magnet, screw, or other form of locking mechanism.FIG. 1Cis a perspective view of one embodiment of the implement102detached from the attachment arm104of handheld tool100, such that a plurality of different implements can be selectively attached to attachment arm104.

Handheld tool100includes tremor tracking module (“TTM”)120for measuring and tracking tremors, such as unintentional high amplitude muscle movements of a user, as well as for controlling stabilization performed by the handheld tool using a first motion generating mechanism (e.g., the first actuator108, first gear reduction unit110, and first gearing unit112) and a second motion generating mechanism (e.g., the second actuator130, second gear reduction unit132, and second gearing unit134), discussed in greater detail below. In embodiments, the attachment arm104is coupled with the housing106via the coupling of the first motion generating mechanism with the second motion generating mechanism. Furthermore, one or more components of TTM120are rigidly attached to housing106to measure and track tremors of the handle that the user holds.FIG. 1Aillustrates TTM120as a single component within housing106; however, in other embodiments, TTM120includes several functional items that may assume a variety of different form factors and may further be spread throughout housing106, such as within attachment arm104.

The illustrated embodiment of handheld tool100further includes at least two motion sensors (e.g., a first motion sensor122placed along or within body and a second motion sensor124placed along or within attachment arm104). The motion sensors122and124respectively measure movements of housing106and attachment arm104, to enable TTM120to determine movements of housing106and attachment arm104relative to one another. The sensor122sends motion signals back to TTM120so that TTM120can determine, in real time or near real time, direction, speed, and magnitude of unintentional high amplitude muscle movements of a user using handheld tool100. These measured movements are provided to TTM120to enable TTM120to provide motion signals that drive the first and second motion generating mechanisms to stabilize the implement102despite the user's unintentional high amplitude muscle movements. In one embodiment, the motion sensors122and124are sensors including but not limited to one or more of an accelerometer, gyroscope, or combination of the two. In another embodiment, each of motion sensor122and124is a inertial measuring unit.

Handheld tool100further includes a portable power source140to power the TTM120, actuator108, and actuator130. The portable power source140can include one or more rechargeable batteries. In embodiments, the rechargeable batteries of portable power source140may be recharged via charging interface142to a charging power source, where charging interface142couples portable power source140to the charging power source via an indicative, wired, or other form of connection. Furthermore, power source140may utilize other options including but not limited to a solar panel, primary batteries, etc.

In one embodiment, the first motion sensor122and second motion sensor124are inertial motion sensors respectively distributed in housing106and attachment arm104. In another embodiment, the second motion sensor124can be an accelerometer with or without a gyroscope. In one embodiment, the first motion sensor122is responsible for measuring movements of the housing106and the second motion sensor124is responsible for measuring movements of the attachment arm104. The first and second motion sensors122and124provide motion signals, indicative of the measured movements, to TTM120for determining the motion of the housing106as well as the relative motions of the housing106and the attachment arm104. In embodiments, one or more of the components for tracking tremor motions and/or performing motion stabilization may be omitted and/or positions of sensors changed while still implementing the tremor tracking and motion stabilization functionality disclosed herein. As examples, rotary encoders, potentiometers, or other position tracking devices placed on the joints of movement of the handheld tool100, and a single motion sensor can be employed either in the tip (e.g., attachment arm104or implement102) or housing106. In these embodiments, the combination of sensors and placement on handheld tool100enable TTM120to infer (through device kinematics) where attachment arm104and housing106are, and their positions relative to each other, for tremor tracking and motion compensation purposes.

The first motion sensor122and second motion sensor124detect unintentional muscle movements and measure signals related to these unintentional muscle movements that are created when a user adversely affects motion of implement102(e.g., as a result of unintentional high amplitude muscle movements). These sensors also detect the motion of the stabilized output relative to the housing106. In one embodiment, the first motion sensor122detects movements of the housing106, although sensor124could also be used for detecting movements of the housing106. Furthermore, the combined measurements of the sensors122and124enable movements of the housing106and implement102relative to one another to also be detected. TTM120sends voltage commands in response to the detected motions to at least one of actuator108and actuator130. The voltage commands are chosen by TTM120to generate a complementary motion to the detected motions of housing106. In one embodiment, the complementary motion is a positioning of attachment arm104upon jointly driving actuator108and actuator130to stabilize implement102(e.g., maintain implement102in a centered position relative to the user's tremors or unintentional muscle movements effecting motion of the handle106). The voltage commands drive one or more of actuator108and actuator130to generate motion of the attachment arm104and therefore the implement102in a direction opposite to the detected user motions. Furthermore, the voltage commands further drive one or more of actuator108and actuator130to generate a motion of equal magnitude of the detected user motion. The voltage commands of TTM120therefore control motion of the implement102by jointly driving the motion generating mechanisms to cancel out the user's unintentional high amplitude motion thereby stabilizing the implement102relative to motion of the housing106by a user.

In one embodiment, the handheld tool100includes a first motion generating mechanism having the first actuator108, first gear reduction unit110, and first gearing unit112. In response to a first set of voltage commands of the TTM120, the first actuator108drives the first gearing unit112through the first gear reduction unit112to move the attachment arm104and the attached implement102on pivot150in a first degree of freedom152relative to the housing106. Similarly, in response to a second set of voltage commands of the TTM120, the second actuator130drives the second gearing unit134through the second gear reduction unit132to move the attachment arm104and the attached implement102on pivot160in a second degree of freedom162relative to the housing106. The first degree of freedom and the second degree of freedom are different, and in one embodiment, the first and second degrees of freedom are perpendicular to one another (e.g., 90 degrees different from one another). In embodiments, the first and/or second motion generating mechanisms employ gearing units that translate motion to orthogonal directions relative to the motions generated by their respective actuators. Such a translation of motion of the actuators to an orthogonal direction can be achieved through bevel gearing units, such as those illustrated inFIGS. 1A-1C. Other types of gearing or combinations of types of gearing, such as work gearing units, a work gearing unit and a bevel gearing unit, etc., capable of translating the actuators'108and130motions to orthogonal directions can be employed by the handheld tool100consistent with the discussion herein.

FIG. 1Billustrates a zoomed in perspective view of the first and second motion generating mechanisms, including the first actuator108, first gear reduction unit110, first gearing unit112that moves an attachment arm in a first degree of freedom through pivot150, as well as the second actuator130, second gear reduction unit132, second gearing unit134that moves the attachment arm in a second degree of freedom through pivot160. As noted above, the attachment arm of the handheld tool is coupled with the housing via the coupling of the first motion generating mechanism with the second motion generating mechanism, such as by having pivots150and160share a common, or connected, structure. Although the illustrated motion generating mechanisms utilize actuators that drive the movement of the attachment via shell gearing units and pivots, in embodiments, other types of actuators and drive units (e.g., direct drive actuators) could be used in the motion generating mechanisms consistent with the discussion herein.

Returning toFIG. 1A, in embodiments, the motions of the attachment arm104and the attached implement102in the first and second degrees of freedom enable TTM120to stabilize implement102in 360 degrees of freedom (e.g., responsive to any pattern and direction of unintentional muscle movements of a user). Furthermore, in embodiments, each of actuators108and130drive its respective gearing unit112and134a distance in the range of 2 cm from peak to peak in its respective degree of freedom, and up to a potential range of 10 cm from peak to peak in its respective degree of freedom. That is, voltage commands from TTM120that jointly drive a position of attachment arm104and the attached implement102via control of actuators108and130provide motion stabilization of implement102(e.g., centering of implement102at a single point in space) up to a total range of 10 cm about the stabilization point in 360 degrees of freedom. Such a range of motion stabilization, provided in real time as a user uses handheld tool100, enables the stabilization of implement102in a range suitable for cancelling unintentional high amplitude muscle movements of a user.

In embodiments, the first actuator108and the second actuator130are each disposed within handheld tool in an orientation parallel to housing106. That is, the first actuator108is parallel and in-line with the body of the housing106, and the second actuator130is parallel and in-line with the body of the body of the attachment arm104. For example, actuators108and130may be substantially cylindrical in shape, and placement of the actuators within and in line with the housing106and attachment arm104ensures that the diameter of the attachment arm and housing can be reduced to a minimum that accommodates the components of the handheld tool.

Then, in order to provide movement of the implement102in the first and second degrees of freedom, the actuators drive their respective gearing units112and134to control motions of the attachment arm104and the attached implement102. Furthermore, by orienting the actuators108and130in this direction, a form factor of the housing108can be reduced, for example, as compared to the form factor needed when an actuator is perpendicular (or another orientation) relative to a handheld tool's housing. Beneficially, reducing the form factor of the housing ensures the handheld tool102more closely resembles a tradition version of the handheld tool, thereby making the handheld tool easy to use. Additionally, users that use the handheld tool102which more closely resembles a tradition version of the handheld tool are more comfortable using such a tool, as it is more familiar and does not resemble a specialized/assistive device.

FIG. 2is a perspective view illustration of another embodiment, of a handheld tool. In the embodiment ofFIG. 2, a sealed handheld tool200that tracks unintentional high amplitude muscle movements and performs motion stabilization, in accordance with an embodiment of the disclosure, is illustrated. The sealed handheld tool200includes a housing206, attachment arm204, and implement202coupled to the attachment arm204. Furthermore, handheld tool200is similar to handheld tool100discussed above, in that it includes a power source, control circuit (e.g., a TTM), a plurality of motion sensors to track movements of the handheld tool200and attachment arm204/implement202, motion generating mechanisms, etc., each configured to perform the functions discussed above inFIG. 1A.

In one embodiment, handheld tool200is sealed to provide a moisture/debris resistance and/or proofing of the motion generating mechanism portions of the handheld tool200. In one embodiment, a barrier, such as a flexible sleeve260, is fixed to the housing206and the attachment arm204. In one embodiment, the flexible sleeve260may be a flexible tube constructed of moisture impermeable silicon, plastic, nylon, rubber, etc. Such a flexible sleeve will protect the gearing units, gear reduction units, and actuators from unwanted moisture and/or debris that may be encountered during use of the implement (e.g., while a user is eating with a spoon implement attached to the handheld tool200), as well as from moisture and debris working its way into the housing206and/or attachment arm204portions of handheld tool200. Beneficially, by providing protection of the motion generating mechanism portions of the handheld tool200, the tool becomes more sturdy and robust for everyday use.

Returning toFIG. 1A, in one embodiment, the voltage commands generated by TTM120drive the actuators, which may be motors that turn their respective gear units. In embodiments, the voltage commands/signals turn the gearing units in a coordinated manner to generate an equal and opposite motion of the attachment arm104and the attached implement102to the direction of detected unintentional high amplitude muscle movements of a user. This cancellation maintains and stabilizes a position of the implement102relative to the housing106.

One of ordinary skill in the art readily recognizes that a system and method in accordance with the present disclosure may utilize various implementations of TTM120that would be within the spirit and scope of the present disclosure. In one embodiment, TTM120comprises an electrical system capable of producing an electrical response from sensor inputs such as a programmable microcontroller a field-programmable gate array (FPGA), an application specific integrated circuit (“ASIC”), or otherwise. In one embodiment, TTM120comprises an 8-bit ATMEGA series programmable microcontroller manufactured by Atmel due to its overall low-cost, low-power consumption and ability to be utilized in high-volume applications.

One of ordinary skill in the art will readily recognize that an apparatus, a system, or method as described herein may be utilized for a variety of applications. For example, various different implements102may include user-assistive devices such as a manufacturing tool, a surgical tool, a kitchen utensil (e.g., fork, knife, spoon), a sporting tool, a yard tool, a grooming tool (e.g., comb, nail clippers, tweezers, make-up applicator, etc.), or a dental hygiene tool (e.g., toothbrush, flossing tool, etc.). The different implements may be detachably attached to the handheld tool100, or may be integrated therewith. Thus, handheld tool100may be useful in not only improving the quality of life for the multitudes of individuals suffering from neurological motion disorders, but also in assisting in a variety of applications where physiological tremor is an issue including but not limited to manufacturing, surgical and public safety applications.

FIG. 3is a functional block diagram illustrating a TTM300, in accordance with an embodiment of the disclosure. TTM300is one possible implementation of TTM120illustrated inFIG. 1A, and TTM220illustrated inFIGS. 2A and 2B. The illustrated embodiment of TTM300includes an inertial measurement unit (“IMU”)305, an IMU307communicably coupled with TTM300, a controller310, a memory unit315, and a communication interface320.

In one embodiment, IMU305is disposed in rigid contact with the housing of a handheld tool to directly measure the tremor motions of the handle and by extension the tremor motions of the user's hand. IMU307is disposed in, or in contact with, an attachment arm of the handheld tool and measures motions of the attachment arm. In one embodiment, IMU305and IMU307have a known orientation relative to one another (e.g., based on a known orientation of the attachment arm to the handle of the handheld tool). TTM300facilitates the measurement of human tremors using IMU305, and optionally IMU307, while a user is performing an everyday task, such as eating or grooming (e.g., applying makeup). This is an important distinction over conventional in-clinic evaluations that simply measure the tremor of a hand that a patient is attempting to hold steady. Measurement and tracking of tremors while the patient is performing an everyday task measures the condition under real-world scenarios that are most adversely impacted by human tremors. Accordingly, TTM300can be embedded within everyday items or tools that are used routinely by patients to accurately measure and track their condition. This can lead to improved evaluations.

Not only can TTM300of a handheld tool measure and track human tremors during a routine task, but it can conveniently do so over a period of time to obtain a more reliable dataset for statistical analysis. Furthermore, the handheld tool including TTM300can be used at home where the user is more relaxed and under less stress than a formal evaluation in a practitioner's office. Data collection within the home environment along with larger datasets than can be obtained in-clinic, can provide more reliable data for evaluation of a patient's symptoms. Improved evaluation and diagnosis of the patient's tremors facilitate improved treatments and interventions of the various diseases and the conditions that cause human tremors.

IMUs305and307may be implemented using a variety of devices that measure motions of the handle of handheld tool100, motions of the attachment arm of handheld tool100, and motions of the handle and attachment arm relative to one another. For example, IMUs305and307may include one or more accelerometers that measure linear accelerations. In one embodiment, IMUs305and307includes accelerometers capable of measuring translational accelerations of the handle and attachment arm in three orthogonal dimensions (e.g., x, y, and z dimensions). In one embodiment, IMUs305and307includes a gyroscope to measure rotational motions (e.g., angular velocity about an axis) of the handle and attachment arm of handheld tool100. In various embodiments, the gyroscope may be capable of measuring the rotational motions about one, two, or three orthogonal rotational axes. In one embodiment, IMUs305and307includes a magnetometer to measure motions of the handle and attachment arm relative to a magnetic field (e.g., Earth's magnetic field or other externally applied magnetic field). In various embodiments, IMUs305and307may include various combinations of some or all of the above listed motion measuring devices. Furthermore, these motion sensors may be disposed together in an IMU on a common substrate that is rigidly attached to housing or attachment arm, or disposed throughout. In one embodiment, by using the combined motion measurements of IMU305and307, other motion sensing devices (e.g., contactless position sensors) need not be deployed within a handheld tool, thereby simplifying the construction of the handheld tool, lowering the cost of the handheld tool, reducing power consumption by the handheld tool, simplifying motion stabilization control performed by controller310, etc.

Controller310is communicatively coupled to IMUs305and307and memory unit315to read motion data output from IMUs305and307and store the motion data into memory unit315. The motion data is collected over a period of time. For example, the motion data may be collected while the user performs an individual task, over the course of a day, a week, or other period of time. The collected motion data stored in memory unit315forms a motion log325. In one embodiment, motion log325may contain enough information about the user's motions (linear accelerations, rotational velocities, durations of these accelerations/velocities, orientation relative to a magnetic field, etc.), based upon the motion data output from IMUs305and307, to recreate those motions using motion log325. In one embodiment, motion log325may also record date/time stamps of when the motion data was collected and even include identifiers indicating the type of implement102that was attached to the handheld tool100when the motion data was collected. The type identifier provides an indication of the activity (e.g., eating with a fork, knife, or spoon, etc.) being performed by the user when the motion data was collected. This activity information and time/date stamps may be useful for the practitioner when evaluating the patient's motion log325to determine if the patient's tremors correlate to particular activities or time of day. In yet other embodiments, motion log325may also record battery voltage as a function of date/time, which may be used to analyzing system performance and battery usage. Tracking battery voltage is a sort of proxy for the amount of effort exerted by actuators108and130to stabilize implement102. As such, tracking battery voltage or battery consumption correlates to the degree of a user's tremors since battery consumption will rise with increased tremors.

In one embodiment, controller310further provides signals to actuators108and130for controlling motion of the attachment arm104and thus the implement102. As discussed herein, the signals generated by controller310cause actuators108and130to jointly move the attachment arm104and the implement102via gearing units112and134in equal and opposite directions as detected user motions of housing106. As discussed herein, the movement of implement102occurs through the combined/joint movement of attachment arm104by actuators108and130, providing stabilization for360degrees of user movement. That is, based on a known orientation of the housing to the implement, motion data collected by the IMUs305and307enables controller310to generate signals that simultaneously drive the first and second actuators in corresponding first and second degrees of freedom to stabilize the implement during high amplitude motion of the handle of a handheld tool.

Controller310may be implemented with a programmable microcontroller, an FPGA, an ASIC, or other devices capable of executing logical instructions. The logical instructions themselves may be hardware logic, software logic (e.g., stored within memory unit315or elsewhere), or a combination of both. Memory unit315may be implemented using volatile or non-volatile memory (e.g., flash memory).

Communication interface320is communicatively coupled to output the motion log325from memory unit315to remote server330via network335(e.g., the Internet). In one embodiment, communication interface320is a wireless communication interface (e.g., Bluetooth, WiFi, etc.). For example, communication interface320may establish a wireless link to a user's cellular phone which delivers motion log325to server330via an installed tremor tracking application. The application may enable the user to control privacy settings, add comments about their usage of handheld tool100, setup automatic periodic reporting of motion log325, initiate a one-time reporting of motion log325, determine a predominant direction of unintentional muscle movements detected by TTM300, receive instructions or an indication as to how to set implement102relative to housing106to enable motion stabilization in a single degree of freedom, along with other user functions. In yet another embodiment, communication interface320may be a wired communication port (e.g., USB port). For example, when the user connects handheld tool100to a charging dock to charge power source122, communication interface320may also establish a communication session with remote server330for delivery of motion log325thereto.

FIG. 4is a flow chart illustrating a process400for tracking unintentional muscle movements of a user while using a handheld tool and performing high amplitude motion stabilization by the handheld tool, in accordance with an embodiment of the disclosure. The process400is performed by processing logic that may comprise hardware (circuitry, dedicated logic, etc.), software (such as is run on a general purpose computer system or a dedicated machine), firmware, or a combination. In one embodiment, the process is performed by a tremor tracking module of a handheld tool (e.g., TTM120or220). Furthermore, the order in which some or all of the process blocks appear in process400should not be deemed limiting. Rather, one of ordinary skill in the art having the benefit of the present disclosure will understand that some of the process blocks may be executed in a variety of orders not illustrated, or even in parallel.

The process begins by handheld tool detecting manipulation by a user while performing an activity (processing block402). In one embodiment, the user uses the handheld tool (e.g., handheld tool100or200) to perform a task or activity, such as a routine everyday activity including eating or grooming. Of course, handheld tool may also be used for other non-routine activities, as described above. In one embodiment, handheld tool detects the manipulation by detecting movement of the handheld tool based on measurements collected from at least one sensor of the handheld tool.

Processing logic tracks user motions with at least two inertial measuring units while the user is manipulating the handheld tool (processing block404). In one embodiment, one of the inertial measuring units may include the sensor used to detect manipulation of the handheld tool by the user discussed above in processing block402. In one embodiment, processing logic detect motion of the handheld tool with the at least two inertial measuring units, and thus movement of a user. Processing logic continues to track user motions while the handheld tool is being manipulated by the user.

Processing logic generates a first motion signal and a second motion signal that respectively drive a first motion generating mechanism in a first degree of freedom and a second motion generating mechanism in a second degree of freedom to stabilize motion of an implement attached to the handheld tool (processing block406). As discussed herein, implement may be attached to an attachment arm of a handheld tool, as discussed above. In one embodiment, the first degree of freedom and the second degree of freedom are different, such as perpendicular to one another. Thus, the combined and simultaneous driving of the motion generating mechanisms in their respective degrees of freedom enables stabilization of the implement in 360 degrees of freedom.