BACKGROUND OF THE INVENTION
The present invention is in the technical field of footwear. More particularly, the present invention is in the technical field of active prosthetic device.
Conventional in-shoe orthoses, (pedorthics) which combine an arch support and medial heel posting (a wedge on the inside of the heel) are commonly used to realign the flat foot into a more neutral position and thus improve gait mechanics. These pedorthics have been shown to improve gait mechanics by supporting the longitudinal arch while reducing plantar and medial soft tissue strain.
Currently available orthotics improve gait biomechanics in flatfoot by passively raising the arch and tilting the hind foot back to neutral. Unfortunately, this static realignment does not mimic the natural function of the foot. In such a fixed position, the foot is too rigid at heel strike and too flexible at toe-off.
SUMMARY OF THE INVENTION
The present invention is an active orthotic device to aid a user's natural foot function. In one embodiment, an active orthotic adjusts the height of the arch and the tilt of the hind foot depending on the phase of the gait cycle. Such an orthotic allows the foot to be supple at heel strike and to be rigid at toe-off, and thus more closely reproduces natural foot function.
In accordance with one aspect of the present invention, an active orthotic device comprises a first insole, a second insole and a plurality of hydraulic chambers disposed between the first insole and the second insole. The hydraulic chambers are configured to hold liquid within an interior of the chamber. The first insole is arranged and configured to bias the plurality of hydraulic chambers in a downward direction. A plurality of tube fittings are provided, where each tube fitting coupled to the plurality of hydraulic chambers.
Then active orthotic device further comprises a plantar pressure sensor disposed on a surface of the first insole and a microprocessor coupled to the plantar pressure sensor. The microprocessor is configured for receiving signals from the plantar pressure sensor and controlling the amount of liquid in the plurality of hydraulic chambers.
Then active orthotic device also has a plurality of hydraulic actuators coupled to the microprocessor and to one of the plurality of hydraulic chambers through one of the plurality of tube fittings. The plurality of hydraulic actuators further has a geared electric motor and a piston, where the piston is configured to add liquid to and remove liquid from the interior of the hydraulic chamber. In addition, the geared electric motor is configured to position the piston in response to signals from the microprocessor. A device compartment is also provided for storing the microprocessor and the plurality of hydraulic actuators.
In accordance with another aspect of the present invention, a method of correcting a user's arch support using an active orthotic device is provided. First, an active orthotic device for correcting a user's arch support is provided, where the active orthotic device has a first insole, a second insole, and a plurality of hydraulic chambers disposed between the first insole and the second insole configured to hold liquid within an interior of the chamber. The first insole is positioned relative the plurality of hydraulic chambers to bias the plurality of hydraulic chambers in a downward direction. The orthotic device also has a plantar pressure sensor disposed on a surface of the first insole configured for detecting the pressure from the arch of a user's foot and a plurality of hydraulic actuators, each coupled to one of the plurality of hydraulic chambers. The plurality of hydraulic actuators are configured to control the amount of liquid in the plurality of hydraulic chambers. Finally, the active orthotic device has a microprocessor coupled to the plantar pressure sensor and the plurality of hydraulic actuator configured for receiving one or more signals from the plantar pressure sensor, and, in response to the one or more signals, controlling movement of the plurality of hydraulic actuators to regulate the quantity of liquid in the plurality of hydraulic chambers.
Then, the system measures the plantar pressure distribution from a user's foot, determines the stepping frequency of the user, and reads statistical information regarding the user's previous steps and, in response, provides an optimized arch support by triggering one or more of the plurality of hydraulic actuators to add or remove liquid from one or more of the plurality of hydraulic chambers in a medial section of the active orthotic device, resulting in raising or lowering of the plurality of hydraulic chambers of the active orthotic device in the medial section. Finally, the system detects the position of the user in the walking cycle, detects the heel angle and detects the stepping frequency of the user and, in response, provides an optimized heel tilt by triggering one or more of the plurality of hydraulic actuators to add or remove liquid from one or more of the plurality of hydraulic chambers in a heel section of the active orthotic device, resulting in raising or lowering of the plurality of hydraulic chambers of the active orthotic device in the heel section of the active orthotic device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of an Active Prosthetic Shoe Device (APSD) according to one embodiment of the present invention showing a device that the user would use on his/her right foot.
FIG. 2 is a side view of the APSD according to one embodiment of the present invention showing the hydraulic chambers (rubber bellows) that separate the bottom and top insole layers.
FIG. 3 is a top view of one embodiment of an APSD; showing the rigid layer to distribute the pressure points from the hydraulic chambers.
FIG. 4 is a bottom view of an AASI according to one embodiment of the present invention showing the layout of the of hydraulic chambers (rubber bellows) in the sole of the shoe of the present invention; and it outlines the path of the fluid lines that lead to the 90 degree tube fittings.
FIG. 5 is a view of the comfort insole that serves to house the hydraulic chambers while they are not inflated.
FIG. 6 shows a condensed hardware outline of the entire system.
FIG. 7 illustrates an isometric view of hydraulic actuator.
FIG. 8 illustrates a compartment that houses all the hardware used in the APSD system.
FIG. 9 top and bottom view of a compartment according to one embodiment of the present invention.
FIG. 10 is a front view of a compartment showing the side view of the hydraulic actuators.
FIG. 11 illustrates a rear isometric view of a compartment according to one embodiment of the present invention showing all the components.
FIG. 12 illustrates a human walking gait cycle.
FIG. 13 shows a flow diagram that illustrates the operation of the active arch mechanism.
FIG. 14 shows a flow diagram that illustrates the operation of the heel tilt mechanism.
FIG. 15 shows a flow diagram that illustrates the hardening of the bottom insole to increase walking efficiency.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1-5 illustrate one embodiment of an Active Prosthetic Shoe Device (APSD) 10 in accordance with one aspect of the present invention. The illustrated embodiment is comprised of three primary active functions. The medial section of the APSD is comprised of a matrix of hydraulic chambers 13. The chambers are typically made of circular channels of a flexible and durable plastic (rubber bellows) that trap fluid and expand depending on the volume of the fluid content found inside. In the illustrated device 10, hydraulic chambers are located in the medial section of the device to actively modify the arch support of a shoe. Continuing with the illustrated embodiment, three hydraulic chambers are located at the heel to actively tilt the heel to the desired angle. In addition, a system is located in the frontal region 30 that makes the plantar side of the device harden at the point before push-off to create a rigid lever and assure an increased transfer of energy.
As shown, the insole 12 is held horizontal above the bottom insole 15 at the point where the foot will contact the device. Typically, the two insoles 12 and 15 are held in the stacked arrangement shown in FIGS. 1 and 2. Insole 12 also serves to push or bias hydraulic cylinders 13 in a downward direction. The APSD 10 dimensions could be modified to suit users of several shoe sizes. The outer edges on the exterior side of the APSD are sown 19 to help align both insoles. On the top of the insole 12 a support insole 11 is located that helps distribute the point forces from the hydraulic chambers and the hydraulic chambers that tilt the heel. In the illustrated embodiment, comfort insole 14 is sandwiched between insole 12 and insole 15 and serves as a housing for the hydraulic chambers. The cylinders are typically housed at cut-outs 19 and 20 when the hydraulic chambers are empty. In operation, the chambers are inflated by directing fluid through the tube fittings 16 and passing through the channels 17 found in the bottom insole 15.
As shown in FIGS. 5 and 6, still referring to the embodiment illustrated in FIGS. 1-5, APSD 10 is shown coupled to a schematic of the hardware involved in the system. The system is typically comprised of a plantar pressure sensor 21 that captures the dynamic in-shoe pressure distribution, which allows determination of accurate pressure patterns during gait and determination of the user's activity or stepping frequency. This sensor 21 is linked to the microprocessor 28, which in turn directs the motor driver 32 to power the geared electric motor 23 using pulse width modulation at high frequencies to allow for precise proportional control. The geared electric motor 23 turns the output gear 35 having an internal thread 25 that matches the thread of the threaded rod 25. By turning the output gear 35 using the geared motor 23 and motor output gear 34, the motor-threaded rod mechanism is converted into a linear actuator that drives piston 26 along hydraulic actuator 22. Typically, the components of each hydraulic actuator 22 are held together by an aluminum bracket 36. The bracket also serves to mount each hydraulic actuator 22 to portable compartment 31 illustrated and described with respect to FIGS. 8-11. The quantity of liquid in each hydraulic chamber 13 is typically determined by the position of the piston 26 along the hydraulic actuator 22, and the position of the piston 26 is determined by an encoder 24 located at the end of the motor responsible for reading the motors turns. Liquid is dispensed to the fittings 16 coupled to the hydraulic chambers 13 through the exhaust 37 of the hydraulic actuator 22. The amount of liquid in each hydraulic chamber 13 creates the correct arch form to help the user's foot function properly and complete a close-loop control system with the reaction forces produced on the plantar pressure sensor 21 by the user's foot.
In the illustrated embodiment, the system is powered by a portable battery 29. Continuing with the illustrated embodiment as shown, each hydraulic chamber 13 is actuated by its own hydraulic actuator. The electronic components in the system, such as the pressure sensors 21, communicate and are powered through data lines 27 that couple the sensor 21 to the microprocessor 28.
Referring to the illustrated embodiment in FIG. 1, the system (sensors, actuators, battery, and all relevant electronics) should be sufficiently small and light weight to wear around the waist or the back. FIGS. 8-11 illustrate a compartment 31 that houses components and is configured to be worn around the back.
In order to better understand the operation of the system, the function in one walking cycle is illustrated and described. The proposed system works by tracking the stepping frequency and the position of the foot in a walking cycle by using a plantar pressure sensor 27 array. The system of the illustrated embodiment is typically comprised of three functions: modifying arch support, tilting the heel and providing a rigid lever at push-of, each function depending upon the variables associated with a person's gait cycle. A typical human's walking gait cycle is illustrated in FIG. 12.
At initial contact with the ground 40 (right foot), as illustrated in FIG. 12, the system of the illustrated embodiment aids the foot by absorbing impact and stabilizing the foot as it makes contact with the ground. The system is configured to zero the hydraulic actuators 46 and run, and then proceed to measure plantar pressure distribution 47, determine stepping frequency 48, read user preferences 49, and access statistical information of the user's previous steps 50. The system provides the user with an optimized arch 51 support in the loading response section 41 of the gait cycle, as illustrated in FIG. 12. If the arch support needs correction 53, the hydraulic actuators 13 are either raised 54 or lowered 55. If the system does not require correction, the system typically enters sleep mode 57 and the timer loop 56 is reset. During mid-stance 42, an optimized arch and heel support should be created for both feet. As the user approaches terminal stance 43, the left foot should be ready to absorb ground reaction forces and prepare the arch support design, and the right foot should be starting to form a rigid lever to help the user push-off the ground. At the point of pre-swing 44, the system should be helping the user support its left foot and help propel its right foot by hardening the bottom of the insole at the proper location, with the proper force and timing (duration). In the last phase of the human walking cycle, called swing 45, the user should have its left foot supported by the APSD 10, system and three mechanisms described above should be relaxed on the right foot, saving energy, and preparing to contact the ground and repeat the cycle.
The system that controls the heel tilt illustrated in FIG. 14, functions by detecting the position of the user in the walking cycle 58, detects the heel angle 59, and finally detects the user's speed (steeping frequency) 60. The system then processes the inputs 61, detects the location of the hydraulic actuators 62, and applies the adequate correction to the heel tilt 63.
The system adjusts the height of the hydraulic chambers 13 by actively filling and emptying the hydraulic chambers 13 in the medial section of the APSD 10 to reproduce an effective arch design that best helps the foot perform its natural function in that walking cycle.
The system that creates the rigid lever in order to increase walking efficiency in flatfoot, found in FIG. 15, will be described. The system initiates and begins by collecting data on past user statistics 64 (where the user typically bends the shoe before push-off, how much force the user applies in that area, and other relevant information). The system detects the stepping frequency of the user 65 and read the user's past settings 66. Once this operation is accomplished, the system detects the user's position in the walking cycle 67 and calculates the following: force to apply 68, position to apply force 69, and time to apply force 70. One these parameters have been calculated and verified, the system actuates the bottom of the insole 71.
The system may be set to change its arch support under a certain condition that a certain percent change in pressure distribution in the medial section of the APSD 10 occurs. Such a change could be caused by the user changing his/her walking speed or taking part in another activity. By using this mode, the system may greatly decrease its power consumption. The mechanism that varies the tilt of the heel is typically active during each cycle as well as the mechanism that hardens the insole before push-off 30. The three hydraulic chambers 13 located in the heel changes their height, and therefore results in that section of the heel to tilt inward or outward (varus or valgus) at a specific point in the walking cycle. The arch design and heel tilt angles depend on the activity, stepping frequency, pressure feedback collected by system (the plantar pressure sensor 27), and statistical values collected from previous walking cycles. The system computes the best arch form, heel tilt, and rigidity factor at push-off to aid an individual reproduce a healthy and optimized foot function. The function of each mechanism is outlined in the flow diagram in FIG. 13.
To determine what configuration will work best for each user, an optimized pressure distribution model may be developed and calibrated from experimental results to suit each user. A large data set is collected from a series of controlled multistep experiments. The results are used to form a conservative arch design that best stabilizes the foot. The computer model is verified by examining the trial-to-trial repeatability and continues to adapt over time to suit the individual needs of that particular person. A feedback controller efficiently manages the arch support of the shoe depending on an optimized mathematical model that determines the form of the arch for a certain stepping frequency and activity.
The construction details of the APSD 10 of the illustrated embodiment shown in FIGS. 1-5 are as follows: top insole layer 12 may be made of leather or any other material that is flexible, has a high friction coefficient, and withstands wear, such as, for example, a neoprene plastic or foam covered with textile. Layer 11 is typically made of a material that is more rigid then layer 12, so as to make sure that the forces exerted upward by the hydraulic chambers 13 are better distributed onto the foot. Hydraulic chambers 13 are typically made of a material such as rubber or silicon that expands and can handle multiple cycles of use without cracking or leaking. The outer wall of the hydraulic chambers 13 is typically reinforced with a textile sleeve to limit hydraulic chamber's 13 lateral expansion. Layer 14 provides a space for the fluid chambers to settle when they are not fully inflated. Layer 14 also serves as a way to bias initial expansion. Layer 14 may be manufactured of a material that is comfortable, such as a gel or silicone. Bottom layer 15 may be casted into a mold that maintains its outer counter and traps the fluid chambers (rubber bellows), fluid lines and tube fittings. This material should be flexible once casted so as to allow for it to flex under use. The interconnections between the fluid chambers, fluid lines, and fluid fittings shall not leak. In one embodiment, the hydraulic actuator is made of 2024 aluminum and uses a double lip o-ring seal. The output gears 34 are typically made out of brass, but any suitable material may be used without departing from the intended scope and spirit of the present invention.
A novel perdorthic device is described that is versatile and adaptive, more so then current static in-shoe orthopedic devices. The present invention illustrated and described with respect to FIGS. 1-15 is an active orthotic that principles may be applied to office chairs or beds. For example, an array of hydraulic chambers 13 would line the seat and backrest of an office chair. The chair itself would compute the pressure distribution being exerted on the chair by the user and would adjust the pressure in each chamber to both modify the user's poster and to equalize the pressure distribution to a predetermined optimized model. In a similar fashion, if hydraulic chambers 13 line the top of a bed, then the system could measure the reaction forces of the person lying on the bed using a pressure sensor array and modify the shape of the hydraulic chambers 13 to best accommodate the shape of the person, ultimately better distributing contact pressure and reducing peak pressure points. Instead of using a higher density liquid, the hydraulic chambers 13 may be inflated with air.
While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention.
Patent Application
20130219745
