Patent Application
20240050246
Over 1.6 million people in the United States are living with lower limb amputation. This number is rising and is expected to double by 2050. Transtibial amputation, or below-knee amputation, has multiple disadvantages due to the loss of most of the calf muscle. Calf muscles, particularly the gastrocnemius and soles muscles, play an important role in supporting the body and propelling it forward.
Passive ankle foot prostheses are widely used due to their low cost, durability, and light weight. The main feature of these devices is their ability to recycle energy during walking. For example, from heel contact to midstance, the carbon fiber foot deforms from the body weight. As the center of mass of the body moves forward in the transition from midstance to terminal stance, the foot starts to return to its original shape, providing support and propulsion energy that was stored in the deformation of the foot. This mechanism of energy recycling is comparable with the calf muscles and Achilles tendon. The musculotendon function of an unimpaired individual can accommodate various walking conditions by manipulating the biological ankle's stiffness and energy return timing to optimally support and propel the body forward. However, the inventors of the present invention recognized downsides of this design. For example, the prostheses made with a carbon fiber blade, the most widely available design, only provide a single stiffness and has no ability to control the energy release timing, leading to improper walking behaviors, i.e., walking asymmetry, increased musculature demands, and excessive joint loads in different walking conditions [1], [2]. Thus, the inventors of the present invention recognized that it is important to have ankle prostheses which can rapidly alter their ankle stiffness to provide efficient and comfortable walking for people with lower limb amputation.
To improve upon single stiffness of ankle foot prostheses by providing an adaptable stiffness under various walking conditions, several semi active prosthetic designs which can alter the stiffness using a combination of elastic components and microprocessors have been suggested. For example, some conventional systems use a tension spring to adjust the torque-angle curve by applying pretension [3], [4]. The inventors of the present invention also recognized downsides of this design. Although the pretension of the spring can provide a fixed increase to the torque applied by the prosthesis, the level of stiffness (the slope of the torque-angle curve) does not change due to the intrinsic character of the applied spring. In order to manage the energy recycling of the prosthetic ankle joint, a highly stiff spring is required and providing pretension from this spring requires powerful actuators which leads to increases in device weight and size. Three-point bending of linear carbon fiber bar has also been suggested to control the level of stiffness [5], [6]. The fulcrum slides along a carbon fiber beam and creates the lowest stiffness when positioned toward the bending point. As the position of the fulcrum deviates from the bending point, the level of stiffness increases. This type of design can provide continuously adaptable stiffness; however, it requires having a stiff foot to maintain the fulcrum rail alignment. In addition to this, the maneuvering speed of the fulcrum may not be fast enough to change the stiffness because the movement of the fulcrum is coupled with an acme screw and requires many rotations of acme screw to move.
The use of a hydraulic cylinder is another approach to modulating the level of stiffness. Commercially available ankle foot prostheses are known that employ hydraulic components to the carbon fiber foot blade [7], [8], [9]. They are designed to adjust the level of impedance on the ankle joint using a hydraulic component to provide custom stiffness or absorb impact during heel contact to improve stability. The inventors of the present invention also recognized one or more downsides of this design. Although the hydraulic cylinders of these prostheses can adjust the level of ankle impedance, they typically act as resistive components that dissipate energy and cannot modulate energy return as they still have a pre-set single stiffness carbon fiber blade that manages energy return [10]. Pneumatic actuators and pneumatic cylinders behave similarly to mechanical springs and have the potential for enabling adjustable stiffness in a prosthesis. For example, pneumatic driven muscle-like actuators are another way to control ankle prostheses [11]. The pneumatic actuators are typically grouped in pairs, an agonist and an antagonist, to control plantarflexion and dorsiflexion because the actuators cannot generate contractile force. As a result, the set of actuators require a larger space than using a single pneumatic cylinder and consume greater amounts of pressurized air.
Prosthetic designs with a pneumatic cylinder also use pressurized air to store energy. Such designs include a semi-active mechanism to provide a wide range of motion for different activities [12]. The pneumatic cylinder compresses and stores energy during dorsiflexion of the ankle, which it returns to the user when the ankle is straightened. When higher pressure is needed to employ a high level of ankle stiffness, an external pressure source, a bike pump, is needed to increase the pressure of the cylinder and reservoir. When a lower pressure is needed, air is manually released from its pressurized chamber. However, in this design, an initial pressure is set and remains fixed during motion. Over time, the chamber will depressurize, and an external pressure supply is needed to recharge the cylinder and reservoir. Another disadvantage of this concept is when the operator increases cylinder pressure, the stable angle of the ankle will change and an unwanted moment will be applied to the body during the stance phase.
To avoid the challenges of integrating an external pressure source, a closed-loop pneumatic system has been suggested to control the stiffness of prosthesis. Such systems use a pneumatic orifice to control the flow of air into the pneumatic cylinder [13]. Dorsiflexion of the ankle joint during mid-terminal stance transfers air into the pneumatic cylinder through the orifice. The diameter of the orifice connecting the pneumatic both sides of the cylinder is modulated, controlling the flow rate of air between two sides of the cylinder and thus the impedance of prosthesis. In fact, changing the flow rate throw the orifice acts as a damper and dissipates energy rather than storing energy resulting in no energy return.
The inventors of the present invention recognized that controlling the level of air pressure and the timing of the release of the pressurized air of the pneumatic cylinder would potentially control of the level of stiffness and energy return timing, respectively. Although employing an external energy supply source (i.e., compressor) allows for this degree of control of the pneumatic cylinder, the inventors of the present invention recognized that compressors are generally heavy, bulky and noisy, so it may be extremely challenging to integrate them into a portable prosthesis which needs to be lightweight and have a compact size for practical use in daily living. Thus, the inventors of the present invention propose a semi-active ankle foot prosthesis that is capable of adjusting stiffness and energy return timing in real time using a hybrid closed loop pneumatic and hydraulic system that can be compact, lightweight, and energy efficient.
In one embodiment, an apparatus is provided for enhancing operation of a leg prothesis. The apparatus includes a variable stiffness module configured to be attached between a first portion and a second portion of a leg prothesis. The first portion is configured to move relative to the second portion in a first plane. The variable stiffness module defines an interior region configured to store pressurized fluid. A volume of the interior region is configured to be varied from a first volume to a second volume such that a stiffness of the variable stiffness module in the first plane is varied from a first stiffness to a second stiffness.
In another embodiment, a method is provided for enhancing operation of a leg prothesis. The method includes attaching a variable stiffness module between a first portion and a second portion of a leg prothesis. The method also includes moving, in a first plane, the first portion relative to the second portion. The method also includes adjusting a volume of an interior region configured to store pressurized fluid within the variable stiffness module from a first volume to a second volume such that a stiffness of the variable stiffness module in the first plane varies from a first stiffness to a second stiffness.
In another embodiment, a leg prosthesis is provided with an apparatus according to the above embodiment mounted thereon.
Still other aspects, features, and advantages are readily apparent from the following detailed description, simply by illustrating a number of particular embodiments and implementations, including the best mode contemplated for carrying out the invention. Other embodiments are also capable of other and different features and advantages, and its several details can be modified in various obvious respects, all without departing from the spirit and scope of the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.
Embodiments are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings in which like reference numerals refer to similar elements and in which:
A method and apparatus are described for enhancing the operation of leg prostheses and/or ankle protheses. In the following description, for the purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known structures and devices are shown in block diagram form in order to avoid unnecessarily obscuring the present invention.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope are approximations, the numerical values set forth in specific non-limiting examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements at the time of this writing. Furthermore, unless otherwise clear from the context, a numerical value presented herein has an implied precision given by the least significant digit. Thus, a value 1.1 implies a value from 1.05 to 1.15. The term “about” is used to indicate a broader range centered on the given value, and unless otherwise clear from the context implies a broader range around the least significant digit, such as “about 1.1” implies a range from 1.0 to 1.2. If the least significant digit is unclear, then the term “about” implies a factor of two, e.g., “about X” implies a value in the range from 0.5× to 2×, for example, about 100 implies a value in a range from 50 to 200. Moreover, all ranges disclosed herein are to be understood to encompass any and all sub-ranges subsumed therein. For example, a range of “less than 10” for a positive only parameter can include any and all sub-ranges between (and including) the minimum value of zero and the maximum value of 10, that is, any and all sub-ranges having a minimum value of equal to or greater than zero and a maximum value of equal to or less than 10, e.g., 1 to 4.
Some embodiments of the invention are described below in the context of enhancing the operation and functionality of leg protheses and/or ankle protheses. For purposes of this invention, “leg protheses” means one or more artificial body parts to replace any part of the leg and/or foot of a subject (e.g., human or non-human) that is not present (e.g., amputated). In an example embodiment, the leg protheses is one or more artificial body parts that replace one or more portions of the leg below the knee (e.g., for a transtibial amputation). In still other embodiments, the leg protheses is one or more artificial body parts that replace one or more portions of the leg above the knee (e.g., for subjects with above knee amputation). In other embodiments, the invention is described below in the context of improving the timing of stiffness adjustment of the leg prothesis based on conditions of movement (e.g., gait phase, speed of movement, incline of movement, surface of movement, etc.) of the user of the leg prothesis. In still other embodiments, the invention is described below in the context of a design of a variable stiffness module that can be applied to prosthetic devices (e.g., prosthetic foot, prosthetic knee or arm, etc.).
In an embodiment, an apparatus 110 is provided to enhance the operation of the leg prothesis 150. In one embodiment, the apparatus 110 excludes the leg prothesis 150. In an example embodiment, the apparatus 110 is a kit that can be installed on an existing leg prothesis to enhance the operation of an existing leg prothesis (e.g., provide adjustable stiffness to the leg prothesis based on movement conditions) and thus convert the existing leg prothesis into an improved leg prothesis. In another example embodiment, the system 100 includes the apparatus 110 and the leg prothesis 150.
In an embodiment, the apparatus 110 includes a variable stiffness module configured to be attached between the first portion (e.g., semi-rigid blade 112) and the second portion (e.g., frame 116) of the leg prothesis 150. As appreciated by one of ordinary skill in the art, different conditions of movement of the leg prothesis 150 (e.g., different gait phase, different speed, different incline, different surface, different gait phase, etc.) require different stiffness levels of the leg prothesis 150.
In an embodiment, the variable stiffness module defines an interior region (not shown in
In this embodiment, the linear actuator also includes a second end coupled to the second portion of the leg prothesis 150. In an example embodiment, the second end of the hydraulic cylinder 111 is rotatably coupled to the frame 116 at a hinge 118. In this embodiment, movement of the semi-rigid blade 112 relative to the frame 116 displaces a piston within the hydraulic cylinder 111 and consequently displaces a first fluid (e.g., hydraulic fluid) within the hydraulic cylinder 111. In an example embodiment, since the first and second ends of the hydraulic cylinder 111 are pivotally coupled to the semi-rigid blade 112 and the frame 116, the hydraulic cylinder 111 is configured to rotate within the first plane based on movement of the blade 112 relative to the frame 116 in the first plane. Although some embodiments disclose that the variable stiffness module is a linear actuator and in other embodiments the linear actuator is a hydraulic cylinder, in still other embodiments the variable stiffness module is not limited to a linear actuator and includes springs.
In one embodiment, the apparatus 110 further includes an accumulator 113 in flow communication with the linear actuator (e.g., hydraulic cylinder 111) to receive the displaced first fluid from the linear actuator and to pressurize a second fluid within the interior region. In some embodiments, the first fluid and second fluid are different (e.g., first fluid is hydraulic fluid and the second fluid is pneumatic fluid). In other embodiments, the first fluid and the second fluid are the same fluid (e.g., hydraulic fluid or pneumatic fluid). In one embodiment, a pneumatic manifold is implemented directly onto the accumulator 113 to reduce the need for piping, to reduce the design complexity and further reduce a risk of leakage. In this embodiment, pneumatic parts (e.g., the reservoir 124 and the pneumatic valves 122) will be mounted onto the accumulator 113 through the manifold to make the design compact (
In one embodiment, the linear actuator (e.g., hydraulic cylinder 111) is attached to the hinges 118, 120 such that it is oriented at an angle relative to the first portion (e.g., portion of the blade 112 that contacts a ground surface) and/or relative to a ground surface, where the angle is about 60 degrees or in a range from about 45 degrees to about 75 degrees or from about 25 degrees to about 75 degrees. The inventors of the present invention recognized that this orientation of the hydraulic cylinder 111 attached to the system further enhances the spatial efficiency of the system (e.g., so the apparatus can fit in the shoe of a user). In an embodiment, the angle is chosen based on certain factors. For example, if the angle is too small, the force will not transmit to the cylinder and prosthesis. In this example embodiment, the inventors recognized that selecting the angle within a range from about 25 degrees to about 75 degrees would effectively transmit this force to the cylinder and prothesis.
In an embodiment, the carbon fiber blade 112 of the passive prosthesis 150 bears most of the force in its deformation, allowing the hydraulic cylinder 111 to modulate the stiffness by increasing it an additional amount (e.g., about 20% or in a range from about 10% to about 30%). In some embodiments, the percentage that the stiffness is modulated can be wider if a bigger size cylinder is used that can manage higher pressure. However, in these embodiments, the bigger size cylinder will increase the overall size and weight of the prothesis.
In one embodiment, the frame 116 of the leg prothesis 150 is an aluminum frame. As shown in
In an embodiment, the goals of the design of the system 100 are to develop an affordable, lightweight ankle prosthesis which adjusts the stiffness and energy release timing of ankle joint during walking. In one embodiment, the variable stiffness module (e.g., hydraulic cylinder 111 and accumulator 113) is capable of increasing the stiffness (e.g., up to about 20%) of the commercially available compliant passive prosthetic blade. Since the prosthetic blade 112 provides a basis of stiffness, the variable stiffness module has a compact, lightweight size (e.g., about 1.4 kg), and aesthetically pleasing exterior that fits inside the user's shoe. In an example embodiment, both a hydraulic and a pneumatic system (e.g., hydraulic cylinder 111 and pneumatic actuator 113) are employed to control the level of stiffness and energy return timing of an ankle foot prosthesis. In an example embodiment, the design of the device combines a standard of care compliant stiffness passive prosthesis and a hydraulic cylinder (e.g., DSNU-32-20-P-S11©, Festo, Esslingen, Germany) to make the prosthesis compact in size and lightweight.
As shown in
In an embodiment, the linear actuator is the hydraulic cylinder 111 including a piston, where the first fluid is hydraulic fluid such that movement of the first portion (e.g., blade 112) relative to the second portion (e.g., frame 116) causes the piston to displace the hydraulic fluid. In this embodiment, the accumulator 113 is in flow communication with the hydraulic cylinder 111 through a hydraulic valve 114. The first chamber 206a of the accumulator 113 is configured to receive the hydraulic fluid from the hydraulic cylinder 111 when the hydraulic valve 114 is in an open position 209 (
In an example embodiment, as the user moves from a first gait phase (e.g., heel strike movement phase 154) to a second gait phase (e.g., mid stance movement phase 156), the weight of the body deforms the prosthetic blade 112, displacing the piston towards the hinge 118. This pushes hydraulic fluid out of the piston and into the accumulator 113, compressing air within the system. During a subsequent third gait phase (e.g., toe off movement phase 162), the pressurized air in hydraulic cylinder 111 applies force to the carbon fiber blade 112 by pushing the head of piston from the hinge 118 to the hinge 120. In this embodiment, this energy return supports and propels the body during walking.
In an embodiment, the first fluid is compressible fluid (e.g., pneumatic fluid) used in the interior region (e.g. second chamber 206b and reservoirs 124) since it can be compressed to act as a spring to restore energy. In this embodiment, the second fluid is incompressible fluid (e.g., hydraulic fluid) that is not used in the interior region since it cannot be compressed to restore energy in this manner. In this embodiment, incompressible fluid (e.g., hydraulic fluid) is used on the other side of the accumulator 113 (e.g. in the first chamber 206a and piping 204).
In an embodiment, as the user moves with the leg prothesis 150, the system 100 alternates between states: a charging mode 201 (
A level of stiffness of the apparatus 110 is based on an volume of the interior region (e.g. collective volume for storing the second fluid). Thus, in some embodiments, the level of stiffness of the apparatus 110 is varied by varying the volume of the interior region. As fluid flows into the accumulator 113, the diaphragm 208 is displaced, reducing the volume of the air chamber 206b and pressurizing it. The total initial volume of the contained air (interior region) depends on the states of the shut-off pneumatic valves 122a through 122d to different sized reservoir chambers 124a through 124d. Different combinations of available reservoirs 124a through 124d correspond to different initial volumes for the accumulator 113 (different interior region volumes). For example, if all shut off valves 122a through 122d are closed, then only the volume of accumulator (volume of the chamber 206b) will be pressurized by movements within the hydraulic system 100. On the other hand, when all shut off valves 122a through 122d are open, associated with the maximum total volume, the sensitivity of pressure to displacement from the hydraulic system 100 is minimized. In an example embodiment, with four unique reservoirs 124a through 124d, sixteen different combinations of initial volume are available corresponding to sixteen different stiffness levels of the prosthesis 150. In the example embodiment of
During the first discharging mode 203 (
In an embodiment, the apparatus 110 includes a sensor 206 configured to measure a value of a parameter that indicates a condition of movement (e.g., a gait phase, one or more of a speed, an incline, a surface of movement, etc.) of a user wearing the legal prothesis 150. In an example embodiment, the sensor 206 is an inertial measurement unit (IMU). In other embodiments, sensors 206 other than an IMU can be used, such as a load cell and a potentiometer that can measure the force and stroke displacement of the cylinder can be used to identify various motions. In an embodiment, the controller 201 is configured to transmit a signal to the valves 112, 114 to move one or more of the valves 112, 114 to an open or closed position. In an embodiment, the controller 201 is a controller board with an embedded sensor 206 (e.g., IMU sensor). In this embodiment,
In an embodiment, the controller 201 is communicatively coupled to the sensor 206 and the valves 114, 122. During operation of the system, the sensor 206 measures the value of the parameter (e.g., value of an acceleration measured by the IMU sensor due ground forces enacted on the leg prothesis 150 at one or more time increments) and transmits a first signal indicating the value of the parameter to the controller 201. In an example embodiment, the sensor 206 measures the value of the parameter that indicates one or more of a speed value, an incline angle value, a gait movement phase and a surface of movement of the user wearing the leg prothesis 150.
In one embodiment, the controller 201 receives the first signal from the sensor 206 indicating the value of the parameter. The controller 201 determines a desired level of stiffness based on the received value of the parameter from the sensor 206 and/or further determines a desired position of each valve 114, 122 to achieve the desired level of stiffness in the cylinder 111. In an example embodiment, the memory 203 of the controller 201 stores first data that indicates a desired level of stiffness of the cylinder 111 in the first plane based on the value of the parameter and/or second data that indicates a desired position of each valve 114, 122 (e.g., charging mode 201 of
In an example embodiment, upon the controller 201 receiving the first signal from the sensor 206 indicating a gait phase of movement of the user, the controller 201 determines a desired level of stiffness (e.g., from data in the memory 203) based on the gait phase. In an example embodiment, where the controller 201 determines that the first signal from the sensor 206 indicates that the user is moving from a heel strike movement phase 154 to a midstance movement phase 156, the controller 201 transmits a signal to the valves 114, 122 to achieve the charging mode 201 arrangement of
In some embodiments, the desired level of stiffness that is stored in the memory 203 is determined in various ways. In one embodiment, the desired level of stiffness is based on determining a level of stiffness attributable to the blade 112 based on the measured parameter from the sensor 206 (e.g. movement phase in the gait cycle 150, speed, etc.). In this embodiment, the level of stiffness of the blade 112 is determined by gathering first data (e.g., that indicates deformation of the blade 112) and second data (e.g., that indicates an amount of ground reaction force imparted by the blade 112 on the ground). In these embodiments, this first data and second data are combined in order to determine the level of stiffness attributed to the blade 112 based on the measured parameter from the sensor 206 (e.g. movement phase of the gait cycle 150).
In an example embodiment, to determine target stiffness levels for the design of the system, a participant was tested with unilateral transtibial amputation (e.g., age 37, weight 107 kg, K-level 4) to determine the range of stiffness for the system. The participant walked on overground force plates 178 (
In an embodiment, the desired level of stiffness that is stored in the memory 203 is based on not only the stiffness level attributable to the blade 112 but also the stiffness level attributable to the variable stiffness module (e.g. apparatus 110). In this embodiment, the desired stiffness level stored in the memory 203 is based on both the stiffness level attributable to the blade 112 and the stiffness level attributable to the variable stiffness module. Since the level of participant's prosthesis is prescribed for the normal walking speed, the stiffness required to achieve an ideal range of +/−10% of original stiffness was determined, intended to facilitate slow and fast walking speeds [16]. In an example embodiment, the design increases prosthetic stiffness, and thus a more compliant passive prosthesis was employed (Cheetah, Ottobock, Berlin, Germany) than the participants' prosthesis to set the minimum stiffness level. In this example embodiment, to generate greater levels of stiffness, the hydraulic cylinder 111 was installed on the prosthetic blade 112.
In step 301, the variable stiffness module (e.g., hydraulic cylinder 111) is attached between the first portion and the second portion of the leg prothesis 150. In one embodiment, in step 301 the hydraulic cylinder 111 is attached between the blade 112 and the frame 116 of the system 100. In an example embodiment, in step 301 the hydraulic cylinder 111 is mounted with the hinge 118 to the blade 112 and with the hinge 120 to the frame 116.
In step 302, the first portion of the leg prothesis is moved relative to the second portion of the leg prothesis in the first plane. In an embodiment, after attaching the leg prothesis 150 to the user in step 301, in step 302 the user initiates a gait cycle with the leg prothesis 150 along a surface. In an example embodiment, in step 302 the blade 112 moves within the PD plane 130 relative to the frame 116 and/or the pylon (e.g., due to effort of the user and/or ground reaction forces).
In step 304, a value of a parameter is measured that indicates a condition of movement of the leg prothesis 150 in step 302. In one embodiment, in step 304 the value of the parameter is measured by the sensor 206. In an example embodiment the parameter includes is one or more of speed, incline, surface of movement, gait movement phase and any other parameter that can be used to characterize a movement of the leg prothesis 150 (e.g., characterize a gait phase). In an example embodiment the sensor 206 is an IMU sensor and/or is configured to measure a current gait movement phase of the leg prothesis 150 at incremental time periods. In an example embodiment, in step 304 the sensor 206 transmits a first signal to the controller 201 that indicates the value of the parameter (e.g., the current movement phase of the gait cycle).
In step 306, a desired level of stiffness for the cylinder is determined based on the value of the parameter measured in step 304. In one embodiment, in step 306 a desired volume of the interior region (e.g., volume of the pneumatic fluid based on the second chamber 206b and one or more of the reservoirs 124a through 124d) is determined based on the desired level of stiffness of the cylinder 111 and/or the value of the parameter (e.g., the current movement phase of the gait cycle). In one embodiment, in step 306 a desired position of the valves 114, 122 (e.g., one of the charging mode 201, first discharging mode 203 and second discharging mode 205) is determined based on the desired level of stiffness and/or the value of the parameter. The position of the valves 114, 122 is adjusted to adjust the volume of the interior region (for the second fluid). In an example embodiment, the memory 203 of the controller 201 stores first data that indicates the desired level of stiffness (e.g., based on the value of the parameter and/or the current movement phase of the gait cycle) and/or second data that indicates the desired position of the valves 114, 122 (e.g., charging mode 201, discharging mode 203 or discharging mode 205). In an embodiment, in step 306 the controller 201 receives the first signal from the sensor 206 and uses the measured value of the parameter to determine the desired level of stiffness and/or desired position of the valves 114, 122 to achieve the desired level of stiffness.
In an example embodiment, the first data and the second data are obtained during a calibration process, e.g., where the leg prothesis 150 is moved at different conditions of movement (e.g., different speeds, different inclines, etc.) and the level of stiffness of the hydraulic cylinder 111 is measured at different positions of the valves 114, 122 (e.g., different interior region volumes). The position of the valves 114, 122 at which the desired level of stiffness in the cylinder 111 is attained is stored in the memory 203 for each movement condition (e.g., for each gait phase). In an example embodiment, the desired level of stiffness is known for different conditions of movement.
In step 308, the volume of the interior region is adjusted from a first volume to a desired volume such that the stiffness of the cylinder 111 is the desired level of stiffness from step 306. In this embodiment, in step 308 one or more of the valves 114, 122 are moved from a first position to a second position (e.g., desired position) such that the stiffness of the cylinder 111 in the second position is the desired level of stiffness determined in step 306.
In an embodiment, the method 300 includes a loop which repeats steps 302 through 308. For each loop of steps 304 through 308, if the movement condition of the leg prothesis (step 304) does not change, then no action is taken in steps 306 and 308.
A sequence of binary digits constitutes digital data that is used to represent a number or code for a character. A bus 410 includes many parallel conductors of information so that information is transferred quickly among devices coupled to the bus 410. One or more processors 402 for processing information are coupled with the bus 410. A processor 402 performs a set of operations on information. The set of operations include bringing information in from the bus 410 and placing information on the bus 410. The set of operations also typically include comparing two or more units of information, shifting positions of units of information, and combining two or more units of information, such as by addition or multiplication. A sequence of operations to be executed by the processor 402 constitutes computer instructions.
Computer system 400 also includes a memory 404 coupled to bus 410. The memory 404, such as a random access memory (RAM) or other dynamic storage device, stores information including computer instructions. Dynamic memory allows information stored therein to be changed by the computer system 400. RAM allows a unit of information stored at a location called a memory address to be stored and retrieved independently of information at neighboring addresses. The memory 404 is also used by the processor 402 to store temporary values during execution of computer instructions. The computer system 400 also includes a read only memory (ROM) 406 or other static storage device coupled to the bus 410 for storing static information, including instructions, that is not changed by the computer system 400. Also coupled to bus 410 is a non-volatile (persistent) storage device 408, such as a magnetic disk or optical disk, for storing information, including instructions, that persists even when the computer system 400 is turned off or otherwise loses power.
Information, including instructions, is provided to the bus 410 for use by the processor from an external input device 412, such as a keyboard containing alphanumeric keys operated by a human user, or a sensor. A sensor detects conditions in its vicinity and transforms those detections into signals compatible with the signals used to represent information in computer system 400. Other external devices coupled to bus 410, used primarily for interacting with humans, include a display device 414, such as a cathode ray tube (CRT) or a liquid crystal display (LCD), for presenting images, and a pointing device 416, such as a mouse or a trackball or cursor direction keys, for controlling a position of a small cursor image presented on the display 414 and issuing commands associated with graphical elements presented on the display 414.
In the illustrated embodiment, special purpose hardware, such as an application specific integrated circuit (IC) 420, is coupled to bus 410. The special purpose hardware is configured to perform operations not performed by processor 402 quickly enough for special purposes. Examples of application specific ICs include graphics accelerator cards for generating images for display 414, cryptographic boards for encrypting and decrypting messages sent over a network, speech recognition, and interfaces to special external devices, such as robotic arms and medical scanning equipment that repeatedly perform some complex sequence of operations that are more efficiently implemented in hardware.
Computer system 400 also includes one or more instances of a communications interface 470 coupled to bus 410. Communication interface 470 provides a two-way communication coupling to a variety of external devices that operate with their own processors, such as printers, scanners and external disks. In general, the coupling is with a network link 478 that is connected to a local network 480 to which a variety of external devices with their own processors are connected. For example, communication interface 470 may be a parallel port or a serial port or a universal serial bus (USB) port on a personal computer. In some embodiments, communications interface 470 is an integrated services digital network (ISDN) card or a digital subscriber line (DSL) card or a telephone modem that provides an information communication connection to a corresponding type of telephone line. In some embodiments, a communication interface 470 is a cable modem that converts signals on bus 410 into signals for a communication connection over a coaxial cable or into optical signals for a communication connection over a fiber optic cable. As another example, communications interface 470 may be a local area network (LAN) card to provide a data communication connection to a compatible LAN, such as Ethernet. Wireless links may also be implemented. Carrier waves, such as acoustic waves and electromagnetic waves, including radio, optical and infrared waves travel through space without wires or cables. Signals include man-made variations in amplitude, frequency, phase, polarization or other physical properties of carrier waves. For wireless links, the communications interface 470 sends and receives electrical, acoustic or electromagnetic signals, including infrared and optical signals, that carry information streams, such as digital data.
The term computer-readable medium is used herein to refer to any medium that participates in providing information to processor 402, including instructions for execution. Such a medium may take many forms, including, but not limited to, non-volatile media, volatile media and transmission media. Non-volatile media include, for example, optical or magnetic disks, such as storage device 408. Volatile media include, for example, dynamic memory 404. Transmission media include, for example, coaxial cables, copper wire, fiber optic cables, and waves that travel through space without wires or cables, such as acoustic waves and electromagnetic waves, including radio, optical and infrared waves. The term computer-readable storage medium is used herein to refer to any medium that participates in providing information to processor 402, except for transmission media.
Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, a hard disk, a magnetic tape, or any other magnetic medium, a compact disk ROM (CD-ROM), a digital video disk (DVD) or any other optical medium, punch cards, paper tape, or any other physical medium with patterns of holes, a RAM, a programmable ROM (PROM), an erasable PROM (EPROM), a FLASH-EPROM, or any other memory chip or cartridge, a carrier wave, or any other medium from which a computer can read. The term non-transitory computer-readable storage medium is used herein to refer to any medium that participates in providing information to processor 402, except for carrier waves and other signals.
Logic encoded in one or more tangible media includes one or both of processor instructions on a computer-readable storage media and special purpose hardware, such as ASIC *420.
Network link 478 typically provides information communication through one or more networks to other devices that use or process the information. For example, network link 478 may provide a connection through local network 480 to a host computer 482 or to equipment 484 operated by an Internet Service Provider (ISP). ISP equipment 484 in turn provides data communication services through the public, world-wide packet-switching communication network of networks now commonly referred to as the Internet 490. A computer called a server 492 connected to the Internet provides a service in response to information received over the Internet. For example, server 492 provides information representing video data for presentation at display 414.
The invention is related to the use of computer system 400 for implementing the techniques described herein. According to one embodiment of the invention, those techniques are performed by computer system 400 in response to processor 402 executing one or more sequences of one or more instructions contained in memory 404. Such instructions, also called software and program code, may be read into memory 404 from another computer-readable medium such as storage device 408. Execution of the sequences of instructions contained in memory 404 causes processor 402 to perform the method steps described herein. In alternative embodiments, hardware, such as application specific integrated circuit 420, may be used in place of or in combination with software to implement the invention. Thus, embodiments of the invention are not limited to any specific combination of hardware and software.
The signals transmitted over network link 478 and other networks through communications interface 470, carry information to and from computer system 400. Computer system 400 can send and receive information, including program code, through the networks 480, 490 among others, through network link 478 and communications interface 470. In an example using the Internet 490, a server 492 transmits program code for a particular application, requested by a message sent from computer 400, through Internet 490, ISP equipment 484, local network 480 and communications interface 470. The received code may be executed by processor 402 as it is received or may be stored in storage device 408 or other non-volatile storage for later execution, or both. In this manner, computer system 400 may obtain application program code in the form of a signal on a carrier wave.
Various forms of computer readable media may be involved in carrying one or more sequence of instructions or data or both to processor 402 for execution. For example, instructions and data may initially be carried on a magnetic disk of a remote computer such as host 482. The remote computer loads the instructions and data into its dynamic memory and sends the instructions and data over a telephone line using a modem. A modem local to the computer system 400 receives the instructions and data on a telephone line and uses an infra-red transmitter to convert the instructions and data to a signal on an infra-red a carrier wave serving as the network link 478. An infrared detector serving as communications interface 470 receives the instructions and data carried in the infrared signal and places information representing the instructions and data onto bus 410. Bus 410 carries the information to memory 404 from which processor 402 retrieves and executes the instructions using some of the data sent with the instructions. The instructions and data received in memory 404 may optionally be stored on storage device 408, either before or after execution by the processor 402.
In one embodiment, the chip set 500 includes a communication mechanism such as a bus 501 for passing information among the components of the chip set 500. A processor 503 has connectivity to the bus 501 to execute instructions and process information stored in, for example, a memory 505. The processor 503 may include one or more processing cores with each core configured to perform independently. A multi-core processor enables multiprocessing within a single physical package. Examples of a multi-core processor include two, four, eight, or greater numbers of processing cores. Alternatively, or in addition, the processor 503 may include one or more microprocessors configured in tandem via the bus 501 to enable independent execution of instructions, pipelining, and multithreading. The processor 503 may also be accompanied with one or more specialized components to perform certain processing functions and tasks such as one or more digital signal processors (DSP) 507, or one or more application-specific integrated circuits (ASIC) 509. A DSP 507 typically is configured to process real-world signals (e.g., sound) in real time independently of the processor 503. Similarly, an ASIC 509 can be configured to performed specialized functions not easily performed by a general purposed processor. Other specialized components to aid in performing the inventive functions described herein include one or more field programmable gate arrays (FPGA) (not shown), one or more controllers (not shown), or one or more other special-purpose computer chips.
The processor 503 and accompanying components have connectivity to the memory 505 via the bus 501. The memory 505 includes both dynamic memory (e.g., RAM, magnetic disk, writable optical disk, etc.) and static memory (e.g., ROM, CD-ROM, etc.) for storing executable instructions that when executed perform one or more steps of a method described herein. The memory 505 also stores the data associated with or generated by the execution of one or more steps of the methods described herein.
Pertinent internal components of the telephone include a Main Control Unit (MCU) 603, a Digital Signal Processor (DSP) 605, and a receiver/transmitter unit including a microphone gain control unit and a speaker gain control unit. A main display unit 607 provides a display to the user in support of various applications and mobile terminal functions that perform or support the steps as described herein. The display 607 includes display circuitry configured to display at least a portion of a user interface of the mobile terminal (e.g., mobile telephone). Additionally, the display 607 and display circuitry are configured to facilitate user control of at least some functions of the mobile terminal. An audio function circuitry 609 includes a microphone 611 and microphone amplifier that amplifies the speech signal output from the microphone 611. The amplified speech signal output from the microphone 611 is fed to a coder/decoder (CODEC) 613.
A radio section 615 amplifies power and converts frequency in order to communicate with a base station, which is included in a mobile communication system, via antenna 617. The power amplifier (PA) 619 and the transmitter/modulation circuitry are operationally responsive to the MCU 603, with an output from the PA 619 coupled to the duplexer 621 or circulator or antenna switch, as known in the art. The PA 619 also couples to a battery interface and power control unit 620.
In use, a user of mobile terminal 601 speaks into the microphone 611 and his or her voice along with any detected background noise is converted into an analog voltage. The analog voltage is then converted into a digital signal through the Analog to Digital Converter (ADC) 623. The control unit 603 routes the digital signal into the DSP 605 for processing therein, such as speech encoding, channel encoding, encrypting, and interleaving. In one embodiment, the processed voice signals are encoded, by units not separately shown, using a cellular transmission protocol such as enhanced data rates for global evolution (EDGE), general packet radio service (GPRS), global system for mobile communications (GSM), Internet protocol multimedia subsystem (IMS), universal mobile telecommunications system (UMTS), etc., as well as any other suitable wireless medium, e.g., microwave access (WiMAX), Long Term Evolution (LTE) networks, code division multiple access (CDMA), wideband code division multiple access (WCDMA), wireless fidelity (WiFi), satellite, and the like, or any combination thereof.
The encoded signals are then routed to an equalizer 625 for compensation of any frequency-dependent impairments that occur during transmission though the air such as phase and amplitude distortion. After equalizing the bit stream, the modulator 627 combines the signal with a RF signal generated in the RF interface 629. The modulator 627 generates a sine wave by way of frequency or phase modulation. In order to prepare the signal for transmission, an up-converter 631 combines the sine wave output from the modulator 627 with another sine wave generated by a synthesizer 633 to achieve the desired frequency of transmission. The signal is then sent through a PA 619 to increase the signal to an appropriate power level. In practical systems, the PA 619 acts as a variable gain amplifier whose gain is controlled by the DSP 605 from information received from a network base station. The signal is then filtered within the duplexer 621 and optionally sent to an antenna coupler 635 to match impedances to provide maximum power transfer. Finally, the signal is transmitted via antenna 617 to a local base station. An automatic gain control (AGC) can be supplied to control the gain of the final stages of the receiver. The signals may be forwarded from there to a remote telephone which may be another cellular telephone, any other mobile phone or a land-line connected to a Public Switched Telephone Network (PSTN), or other telephony networks.
Voice signals transmitted to the mobile terminal 601 are received via antenna 617 and immediately amplified by a low noise amplifier (LNA) 637. A down-converter 639 lowers the carrier frequency while the demodulator 641 strips away the RF leaving only a digital bit stream. The signal then goes through the equalizer 625 and is processed by the DSP 605. A Digital to Analog Converter (DAC) 643 converts the signal and the resulting output is transmitted to the user through the speaker 645, all under control of a Main Control Unit (MCU) 603 which can be implemented as a Central Processing Unit (CPU) (not shown).
The MCU 603 receives various signals including input signals from the keyboard 647. The keyboard 647 and/or the MCU 603 in combination with other user input components (e.g., the microphone 611) comprise a user interface circuitry for managing user input. The MCU 603 runs a user interface software to facilitate user control of at least some functions of the mobile terminal 601 as described herein. The MCU 603 also delivers a display command and a switch command to the display 607 and to the speech output switching controller, respectively. Further, the MCU 603 exchanges information with the DSP 605 and can access an optionally incorporated SIM card 649 and a memory 651. In addition, the MCU 603 executes various control functions required of the terminal. The DSP 605 may, depending upon the implementation, perform any of a variety of conventional digital processing functions on the voice signals. Additionally, DSP 605 determines the background noise level of the local environment from the signals detected by microphone 611 and sets the gain of microphone 611 to a level selected to compensate for the natural tendency of the user of the mobile terminal 601.
The CODEC 613 includes the ADC 623 and DAC 643. The memory 651 stores various data including call incoming tone data and is capable of storing other data including music data received via, e.g., the global Internet. The software module could reside in RAM memory, flash memory, registers, or any other form of writable storage medium known in the art. The memory device 651 may be, but not limited to, a single memory, CD, DVD, ROM, RAM, EEPROM, optical storage, magnetic disk storage, flash memory storage, or any other non-volatile storage medium capable of storing digital data.
An optionally incorporated SIM card 649 carries, for instance, important information, such as the cellular phone number, the carrier supplying service, subscription details, and security information. The SIM card 649 serves primarily to identify the mobile terminal 601 on a radio network. The card 649 also contains a memory for storing a personal telephone number registry, text messages, and user specific mobile terminal settings.
In some embodiments, the mobile terminal 601 includes a digital camera comprising an array of optical detectors, such as charge coupled device (CCD) array 665. The output of the array is image data that is transferred to the MCU for further processing or storage in the memory 651 or both. In the illustrated embodiment, the light impinges on the optical array through a lens 663, such as a pin-hole lens or a material lens made of an optical grade glass or plastic material. In the illustrated embodiment, the mobile terminal 601 includes a light source 661, such as a LED to illuminate a subject for capture by the optical array, e.g., CCD 665. The light source is powered by the battery interface and power control module 620 and controlled by the MCU 603 based on instructions stored or loaded into the MCU 603.
In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. Throughout this specification and the claims, unless the context requires otherwise, the word “comprise” and its variations, such as “comprises” and “comprising,” will be understood to imply the inclusion of a stated item, element or step or group of items, elements or steps but not the exclusion of any other item, element or step or group of items, elements or steps. Furthermore, the indefinite article “a” or “an” is meant to indicate one or more of the item, element or step modified by the article.
This application claims benefit of Provisional Appln. 63/126,683, filed 17 Dec. 2020, the entire contents of which are hereby incorporated by reference as if fully set forth herein, under 35 U.S.C. § 119(e).
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2021/063978 | 12/17/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 63126683 | Dec 2020 | US |
