CN108201477B

CN108201477B - Hand-held tool for leveling uncoordinated actions

Info

Publication number: CN108201477B
Application number: CN201611272927.6A
Authority: CN
Inventors: A·J·帕塔克; M·M·艾伦
Original assignee: Verily Life Sciences LLC
Current assignee: Verily Life Sciences LLC
Priority date: 2016-12-16
Filing date: 2016-12-16
Publication date: 2020-07-17
Anticipated expiration: 2036-12-16
Also published as: CN108201477A

Abstract

A hand tool comprising a handle for holding by a user, a linking arm extending from the handle configured to connect to a user-assistive device, a first inertial measurement unit ("IMU") mounted to the linking arm to acquire measurements for one or more of motion or orientation of the assistive device and generate feedback data indicative of the measurements, an actuator assembly connected to manipulate the user-assistive device in at least two orthogonal dimensions through the linking arm, and a motion control system connected to receive the feedback data from the first IMU and to connect to provide instructions to the actuator assembly to provide automatic leveling of a reference frame by the user-assistive device as the user manipulates the hand tool.

Description

Hand-held tool for leveling uncoordinated actions

Technical Field

The present application relates generally to tools for leveling or stabilizing muscle movements.

Background

Generally, the symptoms of neurological disorders such as Parkinson' S disease, A L S, stroke, multiple sclerosis, or cerebral palsy are signs.

Drawings

Non-limiting or non-exclusive embodiments are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles described.

Fig. 1A is a perspective view of a handheld tool providing self-leveling for a user-assistive device, according to an embodiment of the present disclosure.

Fig. 1B is a partially cut-away perspective view of a handheld tool providing self-leveling for a user-assistive device, according to an embodiment of the present disclosure.

Fig. 1C is a plan view of a handheld tool providing self-leveling for a user-assistive device, according to an embodiment of the present disclosure.

Fig. 1D is a side view of a handheld tool providing self-leveling for a user-assistive device, according to an embodiment of the present disclosure.

Fig. 2 is a functional block diagram illustrating components of a system circuit of a handheld tool providing self-leveling for a user-assistive device, according to an embodiment of the present disclosure.

Fig. 3 is a functional block diagram illustrating components of a motion control system that provides self-leveling for a user-assist device of a handheld tool, in accordance with an embodiment of the present disclosure.

Fig. 4 is a perspective view of a hand tool with a user-assist device made (washed) to hold a cup for drinking according to an embodiment of the present disclosure.

Detailed Description

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

Reference throughout this application 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 present application. Thus, the 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. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

Techniques for assisting human tremor have been developed, but they are not suitable for various situations where human tremor is too extreme in magnitude or tiptoe falls or falls due to lack of muscular control dysfunction. Stabilized platforms using inertial measurement units ("IMUs") have been developed for cameras (e.g., brushless pan-tilt (gimbal) controllers) both in the military and for enthusiasts. The stabilized flight controller similarly stabilizes the mobile platform in three-dimensional space. However, these solutions have not been found feasible to incorporate into small lightweight hand tools to assist people with muscle strength or muscle control limitations to perform everyday tasks such as eating, drinking, or other. Furthermore, certain occupations (e.g., the field of surgery) may benefit from tool leveling and/or stabilization, particularly in high pressure environments, such as operating rooms or even mobile military surgical hospitals.

Fig. 1A-D illustrate a handheld tool 100 capable of self-leveling, and in some embodiments, stabilizing, a user-assistive device 105 attached to the end of the handheld tool 100, according to embodiments of the present application. Fig. 1A is a perspective view of the hand tool 100 and fig. 1B is a partially cut-away perspective view, fig. 1C is a plan view and fig. 1D is a side view, all of the same embodiment of the hand tool 100. The illustrated embodiment of the handheld tool 100 includes a user-assistive device 105, a connecting arm 110, an actuator assembly 115, a handle 120, and system circuitry. The illustrated embodiment of the actuator assembly 115 includes an actuator 125, an actuator 130, a coupling 135, and a coupling 140. The system circuitry includes a leveling IMU145, a motion control system 150, a power source 155, a position sensor (not shown in fig. 1A-D), a system controller 160, a system memory 165, and a communication interface 170. In one embodiment, the handheld tool 100 may also include a shivering IMU 175.

The handheld tool 100 is a self-leveling (and in some embodiments trembling stable) platform that may be adapted to hold a variety of different user-assistive devices 105. The handheld tool 100 provides effective leveling using electronic actuators and a feedback control system. Fig. 1A-D illustrate the user-assistive device 105 as a spoon, however, the user-assistive device 105 may be embodied as a number of different eating implements, drinking implements (see, e.g., cup holder 400 in fig. 4), cosmetic applicators, indicating devices, various professional tools (e.g., surgical tools), or otherwise.

The illustrated embodiment of the handheld tool 100 includes a leveling IMU145 disposed on the attachment arm 145 that is rigidly connected to the user-assistive device 105 to measure the motion and orientation of the user-assistive device 105. The leveling IMU145 outputs feedback data representative of the measured motion and orientation to the motion control system 150. Leveling IMU145 may be implemented with gyroscopes as well as accelerometers, or even additionally include magnetometers. In one embodiment, the leveling IMU145 is a solid state device.

In one embodiment, the motion control system 150 queries the leveling IMU145 for linear acceleration, angular velocity, and orientation relative to a reference frame (e.g., gravity vector) of the user-assistive device 105 at a given time. The motion control system 150 then executes an algorithm to evaluate the orientation of the user-assistive device 105 in three-dimensional space (3D) relative to a reference frame. This estimated or estimated vector of gravity with respect to the leveling IMU (and user-assistive device 105) body frame is continuously updated in real time and used to generate command signals for driving and controlling 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-assistive device 105 to operate the user-assistive device 105 in at least two orthogonal dimensions. In this illustrated embodiment, the two orthogonal dimensions include rotation about pitch axis 180 and rotation about roll axis 185. The pitch axis 180 is orthogonal to the roll axis 185 and extends longitudinally through the handle 120. In other embodiments, the two motion dimensions need not be orthogonal. Moreover, in still further embodiments, additional degrees of freedom may be added to the actuator assembly 115, such as linear motion and even yaw rotation.

An actuator assembly 115 is present in the hand tool 100 to move the connecting arm 110 and to self-level, and in some cases, jerk-stable by extending the user-assistive device 105 relative to the handle 120. If the user-assistive device 105 pitches or rolls relative to a fixed reference frame (e.g., a gravity vector), the motion control system 150 will instruct the actuator assembly 115 to move the user-assistive device 105 in the opposite direction to compensate for and maintain the leveling orientation or even provide an offset orientation to counteract the tremor. The overall effect is that the user-assistive device 105 remains fixed (or even stable) in orientation, regardless of how the handle is oriented within the physical limits of the actuator assembly 115.

The illustrated embodiment of actuator assembly 115 includes an actuator 125 that provides an output rotational motion about a tumble axis 185. This flipping action is connected to actuator 130 via connection 135 such that actuator 125 physically rotates actuator 130 about flipping axis 185. The illustrated embodiment of the actuator 130 provides an output rotational motion about a pitch axis 180. The pitch and roll motions are connected to the link arms and by extending the user-assistive device 105, via the connection 140, cause the actuator 130 to pitch the user-assistive device 105 and the actuator 125 to roll the user-assistive device 105. These orthogonal rotational movements are controlled independently.

In one embodiment, the hand tool 100 further includes two position sensors that provide feedback position information to the motion control system 150 indicative of the rotational position of the outputs of the

actuators

125 and 130 relative to the handle 120. In other words, the position sensor indicates the position of the

connection parts

135 and 140 with respect to the handle 120. In one embodiment, each position sensor is a hall sensor that monitors the position of its

respective connection

135 or 140. Other position sensors including potentiometers, encoders, etc. may also be implemented.

Conventional stabilization devices attempt to provide stabilization using a weighted pendulum (pendulum). However, a heavy mass is required to force the platform to be horizontal. Disadvantages of such an implementation include the required volume and mass and the potential for the pendulum to oscillate and oscillate at its natural frequency. The set point (balance point) of the user-assistive device is limited by the mechanical assembly and cannot be conveniently adjusted. Furthermore, user-related data cannot be collected by these purely mechanical means. In contrast, the feedback control system used in the hand tool 100 is able to achieve much better performance with significantly smaller specifications. No heavy mass is required and the motion control system 150 can be specifically tuned to respond to various involuntary motions (e.g., tremor stabilization). In practice, the motion control system 150 is programmable to respond to uncoordinated motion (low frequency) for automatic leveling and to respond to involuntary motion (high frequency) to stabilize human tremors.

In addition, the system controller 160 may be programmed to monitor and collect data regarding the severity of the user's health condition (e.g., the ability to maintain a horizontal orientation, the amount of reactive control assistance required, the amount of involuntary tremor actions, etc.) and store this data in a log within the system memory 165 for eventual output via the communication interface 170. The log may be analyzed and provided to medical personnel to diagnose and treat the health of the user/patient. The active control provided by motion control system 150 may be further programmed to adjust in smaller increments over time as part of a treatment plan. The treatment plan may be monitored using a diary and customized on a per patient basis by reference to the diary. For example, as one of therapy or training, the amount of active leveling/stabilization is incrementally decreased at a predetermined rate, and the results are periodically monitored with reference to the log.

In one embodiment, the connection arm 110 is implemented as a permanent, fixed connection to a single user-assistive device 105. In other embodiments, the connection arm 110 may facilitate a non-permanent connection to remove or replace the user-assistive device 105. The use of a non-permanent connection enables a user to insert or connect different types of user-assistive devices 105 into the handheld tool 100. For example, the user-assistive device 105 may be implemented as a variety of different eating or drinking utensils (e.g., spoons, knives, teas, cupholders), personal hygiene tools (e.g., toothbrushes, floss bars), grooming tools (e.g., cosmetic applicators, combs), occupational tools (e.g., surgical tools), indicating devices (e.g., laser pens or ferulae), or otherwise. This self-leveling (and optionally tremor stabilization) function may help users with uncoordinated (or involuntary) muscle movements to have improved quality of life by providing greater independent and self-control over daily tasks. Further, the handheld tool 100 may have occupational uses that aid those not suffering from uncoordinated/involuntary muscle movements.

Fig. 2 is a functional block diagram illustrating functional components of a system circuit 200 according to an embodiment of the present invention. The system circuitry 200 illustrates example functional control components for operation of the handheld tool 100. The illustrated embodiment of the system circuitry 200 includes a motion control system 205, a system memory 210, a system controller 215, a communication interface 220, a power supply 225, a leveling IMU230, a position sensor 235, and a tremor IMU 240.

As described above, the motion control system 205 receives (e.g., queries) feedback data from the leveling IMU230 to determine the orientation and motion of the user-assistive device 105. This feedback data is analyzed using a control algorithm to generate commands for manipulating the actuator assembly 115. In one embodiment, motion control system 205 executes as digital signal processing ("DSP") circuitry. In another embodiment, action control system 205 is software/firmware logic executing on system controller 215 and stored in system memory 210. In one embodiment, system controller 215 is implemented as a microprocessor and system memory 210 is a non-volatile memory (e.g., flash memory). Other types of memory and controllers may be used.

In one embodiment, the communication interface 220 is communicatively coupled to the system controller 215 to output data (e.g., usage logs) stored in the system memory 210. The communication interface 220 may be implemented as a wired or wireless interface, such as a universal serial bus ("USB"), a wireless bluetooth interface, a WIFI interface, a cellular interface, or others.

As described above, the leveling IMU230 is configured to monitor the orientation and motion of the user-assistive device 105. In the embodiment shown in fig. 1A-D, the leveling IMU145 is disposed on the attachment arm 145. In embodiments where the user-assistive device 105 is permanently affixed to the handheld tool 100, the leveling IMU230 may also be rigidly mounted to the user-assistive device 105 itself or the attachment arm 110 may be considered an extension of the user-assistive device 105. The leveling IMU230 may be implemented as a solid state sensor including one or more accelerometers, gyroscopes, or magnetometers.

The position sensor 235 is a relative sensor that measures the relative position of the output of the actuator assembly 115 with respect to the handle 120. In one embodiment, the position sensor 235 is a hall sensor that monitors the position of the output of the

actuators

125 and 130 by measuring the position of the

connections

135 and 140. The relative position information output by the position sensor 235 may be logged into a log within the system memory 210 to determine how much auto-leveling the user needs and thus diagnose the severity and progression of a given user.

In one embodiment, the handheld tool 100 may further include a tremor IMU240 rigidly connected to the handle 120 to measure the motion/orientation of the handle 120. Tremor feedback information required by the tremor IMU240 may also be recorded in a log file in the system memory 210 to assist in the diagnosis and treatment of the user's condition. In some embodiments, feedback information from the shivering IMU240 may also be used for feedback stabilization, although feedback information from the leveling IMU230 is sufficient and even preferred for both automatic leveling and stabilization of the user-assistive device 105.

In the illustrated embodiment, the functional components of system circuit 200 may be powered by a power supply 225. In one embodiment, the power source 225 is a rechargeable battery (e.g., a lithium ion battery) disposed within the handle 120 of the hand tool 100. Many other functional components of the system circuit 200 may also be disposed within the handle 120 to provide a compact, 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 supply 225, and the judder IMU240 are disposed within the handle 120. As shown in fig. 1A-D, the actuator 125 and the coupling 135 are at least partially disposed within the handle 120.

Fig. 3 is a functional block diagram illustrating functional components of a motion control system 300 for providing automatic leveling to the user-assistive device 105 of the handheld tool 100, in accordance with an embodiment of the present application. 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, as firmware logic/instructions, as hardware logic, or a combination thereof. In one embodiment, 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 ("L PF") 310, a compensation filter module 315, an evaluation vector module 320, an inverse motion module 325, and a motion controller 330 the motion control system 300 is connected to receive feedback data from a leveling IMU335 and a position sensor 340. the illustrated embodiment of the leveling IMU335 includes a gyroscope 345 and an accelerometer 350.

During operation, gyroscope 345 outputs gyroscope data Δ G and accelerometer 350 outputs acceleration data Δ a. The gyroscope data Δ G is used by the rotation vector module 305 to adjust the previous error vector Sn-1 to produce the current error vector Sn. The current error vector Sn is then provided to the compensation filter module 315. The compensation filter module 315 adjusts the current error vector using a low pass filtered version Δ, a of the accelerometer data Δ a to produce an adjusted error vector S, n. The adjusted error vector S, n is sent back to the estimate vector module 320 where it is locked or temporarily stored and provided to the rotation vector module 305 as the previous error vector Sn-1 for the next cycle of operation.

The adjusted error vector S, n represents a difference vector between a reference frame (e.g., a gravity vector) and a vector representing the current position of the user-assistive device 105. For example, the vector representing the current position of the user-assistive device 105 may be a normal vector extending from a surface on which the leveling IMU145 is disposed. Of course, other vector directions for describing the user-assistive device 105 may be used.

The gyroscope 345 is a fast operating sensor that outputs angular velocity data quickly, but suffers from drift over time. Instead, the accelerometer 350 is a slow sensor that outputs an accurate reading that is used by the compensation filter 315 to update the current error vector Sn and remove any drift. The accelerometer data Δ a is low pass filtered to remove high frequency changes due to sudden jerks, such as judder motion, which are not useful for the low frequency auto-leveling function.

The adjusted error vector S, n is then provided to the inverse motion module 325. The inverse motion module 325 obtains the adjusted error vector S, n and the current position information of the actuator assembly 115 and generates error signals (e.g., pitch error and roll error) that define the position parameters of the

actuators

125 and 130 to obtain the desired position of the user-assistive device 105. The use of kinetic equations is known in robotic control systems.

The error signal is then input into a motion controller 330 that determines how to implement the actual instructions (e.g., pitch instructions and roll instructions) for controlling the actuator assembly 115. In one embodiment, motion controller 330 is implemented as a proportional-integral-derivative ("PID") controller. Motion controller 330 attempts to reduce the error signals (e.g., pitch error and roll error) while also reducing the correction overshoot and oscillation.

In the illustrated embodiment, the motion control system 300 also includes a high frequency path 360 for the accelerometer data Δ a to reach the motion controller 330. The high frequency path 360 allows the unfiltered high frequency accelerometer data Δ a to be analyzed by the motion controller 330 to implement judder stabilization control.

Some of the functional logic/software explained above is described in terms of computer software and hardware. The described techniques may constitute machine-executable instructions embodied within a tangible or non-transitory machine (e.g., computer) readable storage medium, that when executed by a machine, cause the machine to perform the operations described. Further, the process may be implemented within hardware, such as an application specific integrated circuit ("ASIC") or otherwise.

A tangible machine-readable storage medium includes any mechanism that provides (e.g., stores) information in a non-transitory form accessible by a machine (e.g., a computer, an internet appliance, a personal digital assistant, a manufacturing tool, any device with one or more processors, etc.). For example, a machine-readable storage medium includes recordable/non-recordable media (e.g., Read Only Memory (ROM), Random Access Memory (RAM), magnetic disk storage media, optical storage media, flash memory, etc.).

The above description of illustrated embodiments of the invention, including those described in the abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize.

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

Claims

1. A hand tool, comprising:

a handle for holding by a user of the hand tool;

a connecting arm extending from the handle, the connecting arm adapted to mechanically couple to a user-assistive device;

a first inertial measurement unit ("IMU") mounted on the linkage arm to acquire one or more measurements of a motion or orientation of the user-assistive device and to generate feedback data indicative thereof;

an actuator assembly adapted to mechanically connect to the user-assistive device to manipulate the user-assistive device in at least two dimensions through the connecting arm, wherein the actuator assembly comprises:

a first actuator; and

a second actuator, wherein the first actuator is disposed in a handle and the second actuator is disposed outside of the handle; and

a motion control system connected to receive feedback data from the first IMU and connected to provide instructions to the actuator assembly to provide user-assisted automatic leveling of the reference frame as the user operates the handheld tool.

2. A hand tool according to claim 1 wherein the actuator assembly is connected to operate the user-assist device relative to the handle about two axes of rotation.

3. The hand-held tool of claim 2 wherein:

the first actuator controls the overturning action of the connecting arm; and

the second actuator controls the pitch of the connecting arm.

4. The hand-held tool of claim 1, wherein the first IMU is rigidly mounted to the connecting arm.

5. The hand-held tool of claim 3 wherein the actuator assembly further comprises:

a first connection mechanically connecting the flipping motion output from the first actuator to the second actuator, wherein the first actuator is connected to flip the connecting arm by flipping the second actuator via the first connection; and

a second connection mechanically connecting the pitch motion output from the second actuator to the link arm.

6. The hand-held tool of claim 5, wherein the second connection portion is external to the handle.

7. The hand tool of claim 3, further comprising:

a first position sensor connected to monitor a first relative position of a first output of the first actuator; and

a second position sensor connected to monitor a second relative position of a second output of the second actuator,

wherein the first and second position sensors are coupled to feed position information back to the motion control system.

8. The hand-held tool of claim 7, further comprising:

a system controller disposed within the handle and connected to collect position information from the first and second position sensors and record the position information into a log; and

a communication interface connected to the system controller to output the log from the handheld tool.

9. The hand-held tool of claim 2, wherein the motion control system is further coupled to the actuator assembly to manipulate the actuator assembly about two axes of rotation to provide human tremor stabilization to the user-assistive device.

10. The hand-held tool of claim 1 further comprising a power source connected to power the actuator assembly and the motion control system, wherein the power source, the motion control system, and at least a portion of the actuator assembly are disposed within the handle.

11. The hand tool of claim 1, wherein the user-assistive device comprises any one of a eating utensil or a drinking utensil.

12. The hand-held tool of claim 1, wherein the user-assistive device comprises one of an indicating device, a grooming tool, a personal hygiene tool, or an occupational tool.

13. The hand-held tool of claim 1, further comprising:

a second IMU rigidly connected to the handle to measure human tremor while the user is holding and using the handheld tool.

14. At least one machine accessible storage medium providing instructions that, when executed by a handheld tool, cause the handheld tool to perform operations comprising:

measuring at least one of a motion or an orientation of a user-assistive device mounted distally to the handheld tool using an inertial measurement unit ("IMU");

outputting feedback data from the IMU based on the measurement;

monitoring the feedback data in real time using a motion control system disposed at least partially within the hand tool handle; and

controlling an actuator assembly with a motion control system, wherein the actuator assembly is connected to manipulate the user-assistive device in at least two orthogonal dimensions to provide automatic leveling of a reference frame by the user-assistive device when the user manipulates the handheld tool, wherein the actuator assembly comprises a first actuator and a second actuator, and wherein the first actuator is disposed within the handle and the second actuator is disposed outside of the handle.

15. The at least one machine accessible storage medium of claim 14, wherein the at least two orthogonal dimensions include two axes of rotation including a pitch axis and a roll axis.

16. The at least one machine accessible storage medium of claim 15, wherein controlling the actuator assembly with the motion control system to provide self-leveling comprises:

generating an error vector based on the reference frame, which represents a positional deviation of the user-assistive device from the reference vector;

outputting an updated error vector based on feedback data from the IMU; and

based at least in part on the error vector, a pitch instruction to steer the actuator assembly about the pitch axis and a roll instruction to steer the actuator assembly about the roll axis are generated.

17. The at least one machine accessible storage medium of claim 16, wherein the IMU includes a gyroscope and an accelerometer, wherein the feedback data includes gyroscope feedback data and accelerometer feedback data, and wherein controlling an actuator assembly to provide auto-leveling with a motion control system further comprises:

updating the error vector using gyroscope feedback data; and

the accelerometer feedback data is low pass filtered before updating the error vector with the accelerometer feedback data.

18. The at least one machine accessible storage medium of claim 15, further providing instructions that, when executed by the handheld tool, cause the handheld tool to perform further operations comprising:

the actuator assembly is controlled about two axes of rotation with a motion control system to provide human tremor stabilization of the user-assistive device.

19. The at least one machine accessible storage medium of claim 18, wherein controlling actuator components around the two axes of rotation with a motion control system to provide human tremor stabilization comprises:

the accelerometer feedback data output from the accelerometer of the IMU is used without low pass filtered accelerometer feedback data to provide feedback control for human tremor stabilization.

20. The at least one machine accessible storage medium of claim 15, further providing instructions that, when executed by a handheld tool, cause the handheld tool to perform further operations comprising:

collecting position information from one or more position sensors coupled to monitor the position of the actuator assembly relative to the two axes of rotation;

logging the location information into a log; and

the log is output out of the handheld tool through a communication interface.

21. The at least one machine accessible storage medium of claim 14, further providing instructions that, when executed by the handheld tool, cause the handheld tool to perform further operations comprising:

the amount of self-leveling of the user-assistive device provided by the actuator assembly is adjusted over time for treating the user as part of a training plan or treatment plan.

22. The at least one machine accessible storage medium of claim 21, wherein an amount of auto-leveling provided by the actuator assembly decreases over time as part of a treatment plan.

23. The at least one machine accessible storage medium of claim 14, wherein a power source is disposed within a handle of the hand tool and connected to power the actuator assembly and the motion control system and wherein the user-assistive device comprises any one of a eating utensil or a cup holder.