WO2022241218A1 - Fauteuil roulant à actionnement de suspension passif-actif à axes multiples - Google Patents

Fauteuil roulant à actionnement de suspension passif-actif à axes multiples Download PDF

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Publication number
WO2022241218A1
WO2022241218A1 PCT/US2022/029196 US2022029196W WO2022241218A1 WO 2022241218 A1 WO2022241218 A1 WO 2022241218A1 US 2022029196 W US2022029196 W US 2022029196W WO 2022241218 A1 WO2022241218 A1 WO 2022241218A1
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WO
WIPO (PCT)
Prior art keywords
wheelchair
wheel
mass
center
wheel assembly
Prior art date
Application number
PCT/US2022/029196
Other languages
English (en)
Inventor
Rory A. Cooper
Benjamin GEBROSKY
Jorge CANDIOTTI
Joshua KANODE
Sivashankar SIVAKANTHAN
Original Assignee
The United States Government As Represented By The Department Of Veterans Affairs
University Of Pittsburgh -Of The Commonwealth System Of Higher Education
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Filing date
Publication date
Application filed by The United States Government As Represented By The Department Of Veterans Affairs, University Of Pittsburgh -Of The Commonwealth System Of Higher Education filed Critical The United States Government As Represented By The Department Of Veterans Affairs
Publication of WO2022241218A1 publication Critical patent/WO2022241218A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G17/00—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load
    • B60G17/015—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements
    • B60G17/016—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input
    • B60G17/0165—Resilient suspensions having means for adjusting the spring or vibration-damper characteristics, for regulating the distance between a supporting surface and a sprung part of vehicle or for locking suspension during use to meet varying vehicular or surface conditions, e.g. due to speed or load the regulating means comprising electric or electronic elements characterised by their responsiveness, when the vehicle is travelling, to specific motion, a specific condition, or driver input to an external condition, e.g. rough road surface, side wind
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
    • A61G5/04—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs motor-driven
    • A61G5/041—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs motor-driven having a specific drive-type
    • A61G5/043—Mid wheel drive
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
    • A61G5/06—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs with obstacle mounting facilities, e.g. for climbing stairs, kerbs or steps
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
    • A61G5/10—Parts, details or accessories
    • A61G5/1078—Parts, details or accessories with shock absorbers or other suspension arrangements between wheels and frame
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G3/00—Resilient suspensions for a single wheel
    • B60G3/02—Resilient suspensions for a single wheel with a single pivoted arm
    • B60G3/12—Resilient suspensions for a single wheel with a single pivoted arm the arm being essentially parallel to the longitudinal axis of the vehicle
    • B60G3/14—Resilient suspensions for a single wheel with a single pivoted arm the arm being essentially parallel to the longitudinal axis of the vehicle the arm being rigid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G9/00—Resilient suspensions of a rigid axle or axle housing for two or more wheels
    • B60G9/02—Resilient suspensions of a rigid axle or axle housing for two or more wheels the axle or housing being pivotally mounted on the vehicle, e.g. the pivotal axis being parallel to the longitudinal axis of the vehicle
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G2203/00—General characteristics of devices
    • A61G2203/10—General characteristics of devices characterised by specific control means, e.g. for adjustment or steering
    • A61G2203/14—Joysticks
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G2203/00—General characteristics of devices
    • A61G2203/30—General characteristics of devices characterised by sensor means
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G2203/00—General characteristics of devices
    • A61G2203/30—General characteristics of devices characterised by sensor means
    • A61G2203/32—General characteristics of devices characterised by sensor means for force
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
    • A61G2203/00—General characteristics of devices
    • A61G2203/30—General characteristics of devices characterised by sensor means
    • A61G2203/40—General characteristics of devices characterised by sensor means for distance
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2200/00—Indexing codes relating to suspension types
    • B60G2200/10—Independent suspensions
    • B60G2200/13—Independent suspensions with longitudinal arms only
    • B60G2200/132—Independent suspensions with longitudinal arms only with a single trailing arm
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2200/00—Indexing codes relating to suspension types
    • B60G2200/30—Rigid axle suspensions
    • B60G2200/32—Rigid axle suspensions pivoted
    • B60G2200/322—Rigid axle suspensions pivoted with a single pivot point and a straight axle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2202/00—Indexing codes relating to the type of spring, damper or actuator
    • B60G2202/40—Type of actuator
    • B60G2202/41—Fluid actuator
    • B60G2202/413—Hydraulic actuator
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2300/00—Indexing codes relating to the type of vehicle
    • B60G2300/24—Wheelchairs
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/05—Attitude
    • B60G2400/051—Angle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/10—Acceleration; Deceleration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/20—Speed
    • B60G2400/208—Speed of wheel rotation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/25—Stroke; Height; Displacement
    • B60G2400/252—Stroke; Height; Displacement vertical
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/60—Load
    • B60G2400/63—Location of the center of gravity
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/60—Load
    • B60G2400/64—Wheel forces, e.g. on hub, spindle or bearing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2400/00—Indexing codes relating to detected, measured or calculated conditions or factors
    • B60G2400/80—Exterior conditions
    • B60G2400/82—Ground surface
    • B60G2400/823—Obstacle sensing
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2401/00—Indexing codes relating to the type of sensors based on the principle of their operation
    • B60G2401/14—Photo or light sensitive means, e.g. Infrared
    • B60G2401/142—Visual Display Camera, e.g. LCD
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2401/00—Indexing codes relating to the type of sensors based on the principle of their operation
    • B60G2401/17—Magnetic/Electromagnetic
    • B60G2401/174—Radar
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2401/00—Indexing codes relating to the type of sensors based on the principle of their operation
    • B60G2401/21—Laser
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2500/00—Indexing codes relating to the regulated action or device
    • B60G2500/30—Height or ground clearance
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
    • B60G2600/09—Feedback signal
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
    • B60G2600/20—Manual control or setting means
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60G—VEHICLE SUSPENSION ARRANGEMENTS
    • B60G2600/00—Indexing codes relating to particular elements, systems or processes used on suspension systems or suspension control systems
    • B60G2600/20—Manual control or setting means
    • B60G2600/204—Joystick actuated suspension

Definitions

  • This application relates to personal mobility devices and, in particular, to suspension systems of wheelchairs.
  • Wheeled power mobility is critical to allowing individuals with mobility impairments to participate in life activities and advance their lives.
  • the ability to negotiate indoor and outdoor environments, and the obstacles that those environments present, is critical to achieving effective functional mobility.
  • To effectively negotiate the obstacles that are frequently encountered during use of personal powered mobility devices it is important to be able to smoothly navigate irregular and uneven surfaces and overcome curbs, slopes, cross slopes, dips, and bumps in a safe and comfortable manner.
  • a wheelchair comprising a frame coupled to a seat and a pluralit of wheel assemblies.
  • Each wheel assembly can comprise a swing arm that is pivotably coupled to the frame, a wheel rotatably coupled to the swing arm about a respective rotational axis, and an actuator system that is configured to adjust the position of the wheel relative to the frame.
  • the actuator system e g., a passive-active actuator system
  • At least one force sensor can be configured to provide an
  • At least one position sensor can be configured to provide an output associated with a position of the wheel.
  • the wheelchair can further comprise a memory storing therein at least one center of mass threshold and/or movement trajectory.
  • At least one processor can be in communication with the memory and in communication with the force sensor(s) and the position sensor(s) of each wheel assembly.
  • the at least one processor can be configured to: determine, based on the outputs of the force sensor(s) and position sensor(s) of each wheel assembly of the plurality of wheel assemblies, a center of mass of the wheelchair; compare the center of mass of the wheelchair to the at least one center of mass threshold; and adjust, using the actively controlled actuator of at least one wheel assembly of the plurality of wheel assemblies, the center of mass of the wheelchair if the center of mass exceeds the at least one threshold.
  • FIG. 1 is a perspective view of a wheelchair in accordance with embodiments disclosed herein.
  • FIG. 2A shows a side view of a wheel assembly of the wheelchair of FIG. 1.
  • FIG. 2B shows a side perspective view of the wheel assembly of the wheelchair of FIG. 1.
  • FIG. 3 A shows a rear perspective view of the wheel assembly of FIGS. 2A-2B.
  • FIG. 3B shows a rear view of the wheel assembly of FIGS. 2A-2B.
  • the large circles provided on the drawings represent pivot points.
  • FIG. 4 shows a top view of a wheel assembly for a drive wheel of the wheelchair of FIG. 1.
  • FIG. 5 shows a bottom view of the wheel assembly for the drive wheel of FIG. 4.
  • FIG. 6 shows a side perspective view of the wheel assembly for the drive wheel of FIG. 4.
  • FIG. 7 shows a block diagram of an exemplary control loop for controlling the movement of each of the wheel assemblies as disclosed herein.
  • FIG. 8A shows a schematic diagram of a center of mass in relation to center of mass thresholds.
  • FIG. 8B shows a schematic diagram of a cross-section of an ellipsoid-shaped threshold at a first height.
  • FIG. 8C shows a schematic diagram of a cross-section of the ellipsoid-shaped threshold at a second height.
  • FIG. 9 shows a block diagram of sensors and controls of the wheelchair as disclosed herein.
  • FIG. 10 illustrates a computing system comprising a computing device in accordance with embodiments disclosed herein.
  • FIG. 11 A illustrates a first step in climbing an obstacle, such as a curb.
  • FIG. 1 IB illustrates a second step in climbing the obstacle.
  • FIG. 11C illustrates a third step in climbing the obstacle.
  • FIG. 1 ID illustrates a fourth step in climbing the obstacle.
  • FIG. 11E illustrates a fifth step in climbing the obstacle.
  • FIG. 1 IF illustrates a sixth step in climbing the obstacle.
  • FIG. 12A illustrates a first step in descending an obstacle, such as a curb.
  • FIG. 12B illustrates a second step in descending the obstacle.
  • FIG. 12C illustrates a third step in descending the obstacle.
  • FIG. 12D illustrates a fourth step in descending the obstacle.
  • FIG. 12E illustrates a fifth step in descending the obstacle.
  • FIG. 12F illustrates a sixth step in descending the obstacle.
  • FIG. 13A depicts an exemplary machine vision sensor system.
  • FIG. 13B shows a sensed area and calculated data associated with the sensed area, the calculated data usable for traversing the sensed area and which can be provided on a display.
  • FIG. 14A illustrates a schematic diagram for an exemplary wheelchair as disclosed herein.
  • FIG. 14B shows a schematic diagram for a wheelchair without active actuation.
  • FIG. 15 shows four obstacles traversed by an exemplary wheelchair as disclosed herein.
  • FIGS. 16A-16B show respective charts of root mean square (RMS) and vibration dose values (VDV) for 1) a conventional electric wheelchair, 2) a wheelchair as disclosed herein without active suspension, and 3) a wheelchair as disclosed herein with active suspension across different obstacles.
  • RMS root mean square
  • VDV vibration dose values
  • FIGS. 17A-17B show respective charts of root mean square (RMS) and vibration dose values (VDV) for 1) a conventional electric wheelchair, 2) a wheelchair as disclosed herein without active suspension, and 3) a wheelchair as disclosed herein with active suspension across different obstacles.
  • RMS root mean square
  • VDV vibration dose values
  • FIG. 18 is a schematic showing input devices and user interface screens for operating an exemplary wheelchair as disclosed herein.
  • FIG. 19 shows an exemplary wheelchair in a raised configuration.
  • FIG. 20 shows a flow chart of an algorithm for ascending and descending an obstacle with the exemplary wheelchair as disclosed herein.
  • FIG. 21 is a simplified schematic diagram illustrating the linkage of a drive wheel and carriage. As shown, larger circles indicate pivot points that are not movable relative to the carriage, and smaller circles indicate pivot points that are movable relative to the carriage.
  • Ranges may be expressed herein as from “about” one particular value, and/or to “about” another particular value. When such a range is expressed, also specifically contemplated and considered disclosed is the range from the one particular value and/or to the other particular value unless the context specifically indicates otherwise. Similarly, when values are expressed as approximations, by use of the antecedent “about,” it will be understood that the particular value forms another, specifically contemplated embodiment that should be considered disclosed unless the context specifically indicates otherwise. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint unless the context specifically indicates otherwise.
  • the word “comprise” and variations of the word, such as “comprising” and “comprises,” means “including but not limited to,” and is not intended to exclude, for example, other additives, components, integers or steps.
  • each step comprises what is listed (unless that step includes a limiting term such as “consisting of’), meaning that each step is not intended to exclude, for example, other additives, components, integers or steps that are not listed in the step.
  • caster should be understood to include both conventional casters (e.g., wheels that swivel about an axis that is perpendicular to their axis of rotation) as well as omni-wheels, which include rollers that permit movement perpendicular to the axis of rotation of the wheel.
  • conventional casters e.g., wheels that swivel about an axis that is perpendicular to their axis of rotation
  • omni-wheels which include rollers that permit movement perpendicular to the axis of rotation of the wheel.
  • a wheelchair 10 having a seat 12 and a frame 14 coupled to the seat.
  • the wheelchair 10 can have a longitudinal axis 6 that extends between a front and a rear of the wheelchair 10 and a transverse axis 8 that is perpendicular to the longitudinal axis and extends between left and right sides of the wheelchair.
  • a plurality of wheel assemblies 20 can couple to the frame 14 so that the plurality of wheel assemblies distribute the weight of the wheelchair on the ground.
  • the plurality of wheel assemblies 20 can comprise a pair of drive wheel assemblies 22, with the two drive wheel assemblies of the pair being positioned on opposing sides of the frame 14.
  • the plurality of wheel assemblies 20 can further comprise at least one freely rotating wheel assembly 24.
  • the freely rotating wheel assembly (or assemblies) 24 can optionally be positioned rearwardly of the drive wheel assemblies 22 along the longitudinal axis 6.
  • the at least one freely rotating wheel assembly 24 can consist of a single freely rotating wheel assembly that is positioned rearwardly of the drive wheel assemblies 22 along the longitudinal axis 6.
  • the wheelchair can further comprise freely rotating front wheels 100.
  • the freely rotating wheel assembly 24 can comprise a swing arm 30 that is pivotably coupled to the frame 14 about a pivot axis 31. At least one wheel 32 can be coupled to the swing arm 30 and rotatable about a rotational axis 34.
  • An actuator system 36 can be configured to adjust the position of the swing arm 30 relative to the frame, thereby adjusting a vertical position of the wheel relative to the frame 14.
  • the actuator system 36 can comprise an actively controlled actuator 38 and a passive shock absorber 40 that is coupled to the actively controlled actuator 38 in series. That is, the actively controlled actuator 38 and the passive shock absorber 40 can each independently affect the vertical position of the wheel to which the actuators are coupled. Accordingly, each of the wheels can move in response to the driving surface through the shock absorber or in response to the movement of the active actuator.
  • the passive shock absorbers 40 can be linear shock absorbers having a first end 42 and a second end 44, wherein a biasing element (not shown, but as is conventionally provided within linear shock absorbers) can bias the first end away from the second end.
  • the biasing element can be, for example, a coil spring or a gas spring or both.
  • the first end 42 can couple to the swing arm 30, and the second end 44 can be coupled to the actively controlled actuator 38 via a linkage 46.
  • actuation of the actively controlled actuator can determine a position of the first end of the passive shock absorber, and the biasing element of the passive shock absorber can allow movement of the second end of the passive shock absorber relative to the first end to provide passive suspension of the wheel(s) 32.
  • the wheelchair disclosed herein can be driven via an on board power supply (e.g., a battery 116 - FIG. 9). It is contemplated that use of a passive shock absorber can significantly reduce an energy load on the power source as compared to using an active suspension to absorb small perturbations.
  • the linkage 46 can comprise a first linkage element 48 that is pivotably coupled to the frame 14 about a pivot axis 50, wherein a first end 52 of the first linkage element is coupled to the actively controlled actuator 38 (e.g., via a piston rod 54 of the actively controlled actuator).
  • a second end 56 of the first linkage element 48 can couple to a first end 58 of a second linkage element 60.
  • a third linkage element 62 can couple to the frame 14 at a first end 64.
  • a second end 66 of the second linkage element 60 can couple to a second end 68 of the third linkage element 62.
  • the second end 68 of the third linkage element 62 can couple to the second end of the passive shock absorber 40.
  • first, second, and third linkage elements 48, 56, 62 can define a four-bar linkage that can adjust the second end of the passive shock absorber 40.
  • the freely rotating wheel assembly 24 can comprise a pair of wheels 32 that are spaced along the transverse axis 8 on an axle 33.
  • the wheels 32 can couple to the swing arm 30 via a torsion joint 69 that can enable the wheels to pivot about a torsion axis 71 (that can optionally be parallel to, or coaxial with, the longitudinal axis 6).
  • the torsion joint 69 can be actively or passively controlled.
  • a passive biasing element 73 can bias the torsion joint toward a position in which a rotational axis 34 of the wheels is parallel to the transverse axis 8.
  • the passive biasing element 73 can comprise an elastomeric material (e.g., polyurethane).
  • the passive biasing element 73 can comprise first and second components on each side of the torsion axis 71.
  • the first and second components can be received between blind holes in each of the swing arm 30 and the axle 33 on either side of the torsion axis 71.
  • pivotal movement of the axle 33 relative to the swing arm 30 about the torsion axis 71 can apply a shear force to the elastomeric material.
  • the elastomeric material can comprise a rigid element (e g., a steel rod) that extends through the elastomeric material (optionally , through the center of the elastomeric material).
  • the rigid element can retain the elastomeric material in compression to inhibit tearing or shearing of the elastomeric material.
  • a rotational actuator can actively adjust the rotational axis of the wheels 34 about the torsion axis 71.
  • the actuator can be configured to actively maintain both of the wheels 32 in contact with the ground surface.
  • each of the drive wheel assemblies 22 can comprise a swing arm 70 that is pivotably coupled to the frame 14 about a pivot axis 72.
  • a drive wheel 74 can be rotatably coupled to the swing arm at a first end 80 about a rotational axis 76.
  • a drive motor 78 can be coupled to the drive wheel 74 and configured to cause the drive wheel to rotate.
  • An actuator sy stem 82 can be configured to adjust the vertical position of the drive wheel 72 relative to the frame 14.
  • the actuator system 82 can pivotably couple to the swing arm 70 at a pivotable coupling 83 at a second end of the swing arm with the pivot axis 72 between the coupling of the drive wheel 74 to the swing arm and the coupling between the actuation sy stem 82 and the swing arm.
  • each drive wheel assembly 22 can comprise an actively controlled actuator 84 coupled in series to a passive shock absorber 86
  • the actively controlled actuator 84 can be a linear actuator that has a first end that is pivotably coupled to the swing arm 70 at the pivotable coupling 83.
  • the actively controlled actuator 84 can comprise a piston rod 88 that is parallel or generally parallel to (e.g., within 15 degrees of, 10 degrees of, or 5 degrees of, or 1 degree of) the longitudinal axis 6 of the wheelchair.
  • the passive shock absorber 86 can have a first end 90 that is movable (e.g., axially movable) relative to a second end 92.
  • the first end 90 of the passive shock absorber 86 can couple to the carriage 95 at a pivot point 87.
  • the piston rod 88 can be coupled to the second end 92 of the passive shock absorber 86.
  • a linkage 94 e.g., a four-bar linkage
  • the linkage 94 can further set or establish a mechanical advantage between the movement of the passive shock absorber and the actively controlled actuator 84.
  • the linkage 94 can be configured so that movement of the piston rod 88 in a first direction can cause movement of the second end 92 of the passive shock absorber 86 in a second direction that is opposite or generally opposite the first direction (e.g., as shown and described for the freely rotating wheel assembly 24).
  • movement of the piston rod 88 in a first direction can cause movement of the second end 92 of the passive shock absorber 86 in a second direction that is opposite or generally opposite the first direction (e.g., as shown and described for the freely rotating wheel assembly 24).
  • forw ard movement of the piston rod 88 can cause rearward movement of the second end of the passive shock absorber.
  • This configuration can provide for a compact configuration.
  • each of the actively controlled actuator and the passive shock absorber can be elongate in the respective dimension in which it extends and retracts. Accordingly, in providing a linkage as described herein, the actively controlled actuator and the passive shock absorber can be positioned alongside each other. The same advantage can be appreciated with the configuration of the freely rotating wheel
  • the active actuators 38, 84 can be electrohydraulic actuators.
  • one or more electric motors 96 can be configured to provide hydraulic power to the hydraulic actuators.
  • Each of the wheel assemblies 20 can comprise a force sensor 102 that is configured to determine a ground force applied by the ground to the respective wheel.
  • the force sensor 102 can be positioned anywhere within the coupling between the wheel and the frame so that the weight against the wheel causes a proportional force against the force sensor.
  • the force sensor 102 of the drive wheel assembly 22 can be positioned between the linkage 94 and the swing arm 70 (e.g., between the swing
  • the force measured by force sensor 102 can be converted to the ground force experienced by the respective wheel.
  • Each of the wheel assemblies 20 can further comprise a position sensor 104 that is configured to provide an output associated with a position of the respective wheel.
  • the position sensor 104 can be a rotary sensor that is configured to detect a rotational position of the swing arm 30,70 (of a respective wheel assembly 20) that can be used to determine a position of the wheel relative to the frame (e.g., a vertical position of the wheel relative to the frame).
  • the position sensor 104 can be a linear sensor.
  • the linear sensor can be coupled to the swing arm and the frame at respective fixed points. Using geometry of the triangle defined by the hinge point of the swing arm and the fixed points, the angle of the swing arm can be determined.
  • the position sensors 104 can be linear or rotary encoders, potentiometers, and/or LVDs.
  • the wheelchair 10 can further comprise one or more orientation sensors 106.
  • the wheelchair 10 can further comprise one or more acceleration sensors 108 (e.g., accelerometers).
  • the acceleration sensors 108 can be configured to detect vibration (e.g., amplitude and/or frequency).
  • the acceleration sensors 108 can be configured to detect shock.
  • the accelerometers can be configured to determine speed and orientation (e.g., using numerical integration of acceleration measurements).
  • the wheelchair 10 can further comprise one or more speed sensors 110.
  • the speed sensors(s) 110 can be respective encoders that are in communication with each drive wheel 74.
  • the speed sensor(s) 110 can determine speed, for example, angular velocity of the drive wheels, to thereby determine linear speed of the wheelchair.
  • the wheelchair can, based on feedback from the speed sensors 110, regulate a top speed of the wheelchair. It is contemplated that the speed sensors can be used in conjunction with a computing device and various other sensors, further described herein, to determine a maximum speed for a particular circumstance or mode in order to limit overspeeding of the wheelchair.
  • the computing device is configured to regulate a maximum speed of the wheelchair based on a proximity of the center of mass to at least one threshold as further disclosed herein.
  • the maximum speed can be limited based on a quality of the terrain (e.g., bumpiness as measured by the
  • the wheelchair can have limited speed based on a mode such as, for example, during self-leveling, during curb ascending/descending, etc.
  • the wheelchair can comprise at least one machine vision sensor 112 (see also FIG. 13 A) such as, for example, one or more cameras, one or more laser range finders, and/or RADAR/LIDAR.
  • the cameras, LIDAR, and/or RADAR can be used in conjunction with a computing device, further disclosed herein, to detect and characterize obstacles for path determination.
  • the machine vision sensor(s) 112 can be used to detect a curb that the wheelchair is configured to traverse.
  • the machine vision sensor(s) 112 can be used detect a ramp (or other alternative path) to avoid a curb, stairs, or other obstacle.
  • the machine vision sensor(s) 112 can assist in accelerating negotiation of various terrain.
  • the wheelchair 10 can comprise a computing device 1001 (FIG. 10) that can be in communication with the various sensors (e.g., force sensors 102, position sensors 104, orientation sensor(s) 106, acceleration sensors 108, speed sensors 110, and/or machine vision sensors 112) of the wheelchair.
  • the computing device 1001 can be configured to control, based on feedback from the various sensors, various aspects of the wheelchair 10, including at least some (optionally, all) of the following: regulation of the seat orientation and attitude, obstacles detection and classification, path planning with flexible execution (i.e., path for curb climbing is statically stable and reversible at any point along the execution path), combined passive-active suspension for shock and vibration suppression.
  • the computing device 1001 can use one or more feedback loops that control the speed and direction of each vertical wheel movement and activation of its actuators to maintain a Center of Mass 118 (COM) within safety boundaries.
  • the computing device can have a memory 1012 that stores one or more center of mass thresholds 120.
  • the center of mass thresholds can be a forward threshold 120a, a rearward threshold 120b, a left-side threshold 120c and a right-side threshold 120d.
  • the center of mass threshold 120 can be defined by at least a portion of an ellipsoid. For example, FIG.
  • FIG. 8B shows a cross section of the center of mass threshold ellipsoid, taken at a first height from the ground
  • FIG. 8C shows a cross section of the center of mass threshold ellipsoid, taken from a second height that is greater than the first height.
  • the ellipsoid can have a center that corresponds to the center of mass when the user is seated on the wheelchair and
  • the wheelchair is on flat, level ground. Accordingly, in some aspects, the higher the center of mass of the wheelchair is, the less tilt can be allowable.
  • the center of mass threshold can be calibrated on a reference surface with the user in the wheelchair.
  • the center of mass threshold ellipsoid (or other threshold boundary) can be scaled by a safety factor from a maximum- tolerance center of mass threshold ellipsoid (or other threshold boundary). For example, the center of mass tolerance can be scaled as a fraction of maximum tolerance of the safety factor (e.g., (maximum tolerance)/ (safety factor)).
  • a safety factor of 2 can set the center of mass tolerances to half of the distance between the origin and the maximum tolerance center of mass threshold ellipses. Accordingly, the wheelchair can be configured to maintain the center of mass within 50% of the end point of the stability limit of each axis of the ellipsoid.
  • the threshold 120 can be modified based on the movement of the passive shock absorbers 40.
  • the wheelchair can increase the safety factor in response to detecting excessively bumpy terrain (e.g., as sensed by the accelerometers 108 or a sensor associated with the passive shock absorbers).
  • the actively controlled actuators 38 can move to adjust the center of mass away from a closest portion of threshold 120.
  • the computing device 1001 can begin by calculating a Center of Mass (COM) Reference Model, via each wheel arm (w, /), using Vertical Force (Fzw, i ) and Joint Angle (Ww, i ) that includes both the user and wheelchair mass.
  • the COM reference model can be used to determine the desired wheel arm vertical forces.
  • the computing device can use said desired wheel arm vertical forces for low-level control.
  • the low-level control can determine the speed and direction of each wheel arm based on the desired vertical force and estimated vertical position (I.w) and acceleration (tw) of each wheel arm.
  • the latter two variables can be estimated through the powered personal wheeled mobility device inverse kinematics.
  • a gain scheduling system can affects the direction and activation of each wheel based on threshold values set by the seat angles (pitch (Oscai) and roll (bk»)) and vertical acceleration (vibration ( ⁇ 3 ⁇ 4)) of the seat. For example, if a z is higher than a predetermined vibration threshold but the seat angles (or center of mass) are within
  • the actively controlled (swing arm) actuators 38,84 can be inhibited to offer a passive suspension via the shock absorbers; however, if the seat angles (or center of mass) are over their safety threshold, regardless of the vibration, then the actuators can be engaged to maintain the seat orientation and attitude. In this way, the wheelchair can avoid excessive actuator movement that can dram power or exhaust actuator duty cycle.
  • the COM location is calculated with powered personal wheeled mobility device dynamics to compare the reference model to the current state of the wheelchair.
  • the disclosed wheelchair can automatically, based on sensed parameters, alternate between position control, in which the active actuators 38 maintain the center of mass within the threshold(s) 120, and force control, in which the actuators actively accommodate ground forces of the wheelchair to keep the wheelchair stable and improve the comfort of the user.
  • determining the center of mass of the wheelchair as described herein can, by using ground force measurements, account for the weight of the user as well as the seated position of the user. This can be superior to actively controlled suspensions systems that neglect the weight of the user.
  • the computing device can inhibit actuation of the passive shock absorbers when the COM is outside of the thresholds.
  • the computing device can, based on the center of mass being outside of at least one threshold, lock the passive shock absorbers to inhibit further movement of the COM away from the threshold.
  • the passive shock absorbers 40 can comprise sensors that are configured to detect rate and/or amount of compression.
  • the passive shock absorbers can have variable dampening impedance.
  • the passive shock absorbers can be gas springs in which movement of the gas spring causes fluid to pass through an orifice. It is contemplated that the size of the orifice can be adjusted in order to change the dampening impedance of the actuators. In this way, the impedance dampening can be tuned to different frequencies and loads.
  • the computing device can adjust the impedance dampening of the passive shock absorber based on the vibration frequency detected by the acceleration sensors 108.
  • the shock absorbers can comprise an electro-hydraulic valve that is configured to change
  • the wheelchair can comprise pneumatic actuators that use an air source (e.g., a pump or a compressed gas cylinder) to adjust the impedance of the passive shock absorber.
  • an air source e.g., a pump or a compressed gas cylinder
  • the ground force measurements can be used to determine a weight of the user in the wheelchair.
  • the computing device can sum the ground forces of all of the wheel assemblies 20, subtract the weight of the wheelchair 10, and output the difference (e.g., to a display device 1011 (FIG. 10)).
  • the drive wheel assemblies 22 can be movable forwardly and rearwardly along the longitudinal axis relative to the frame 14 of the wheelchair 10.
  • the drive wheel assemblies 22 can couple to the frame by respective carriages 95 that are movable forwardly and rearwardly along the frame 14.
  • the carriages 95 can move along one or more tracks 97 (FIGS. 1 IB and 11C).
  • at least one track on each side of the frame can comprise a rack 98 defining teeth.
  • An actuator e.g., an electric motor
  • the drive wheels can be positioned to optimally distribute load for balance.
  • the forward and rearward movement of the drive wheels can enable traversing of obstacles as further described herein.
  • the computing device can cause the wheelchair to climb over an obstacle. Further details for obstacle climbing are described in U.S. Patent No. 10,912,688 (the ‘688 Patent), granted May 9, 2021, the entirety of which is hereby incorporated by reference herein. It should be understood that the wheels 32 can be raised and lowered via a single actively controlled actuator 38. Similarly, it is contemplated that the front casters 100 can be raised via a single actuator 130. Accordingly, it is contemplated that the methods for climbing a curb described in the ‘688 Patent can be consistent with operation of the wheelchair 10 described herein. Moreover, in optional aspects, a single actuator can raise and lower the wheels 32, and a single actuator can raise and lower the front casters 100. Further details of obstacle navigation are disclosed herein in Example 1 and with reference to FIGS. 11-12.
  • the computing device can, in conjunction with the machine vision sensors 112, perform obstacle detection and classification.
  • the computing device can further perform path planning with flexible execution. For example, a path for curb climbing can be used as it is statically stable and reversible at any point along the execution path).
  • the machine vision sensors 112 can detect an obstacle (e.g., a curb).
  • the computing device 1000 can determine one or more proposed paths. For example, a first proposed path can be circumventing the obstacle. A second proposed path can be, for example, a preferred path to climb the obstacle.
  • the path can include aligning the wheelchair with the longitudinal axis 6 orthogonal (or within 5 degrees or 10 degrees of horizontal) to the curb. The computing device 1000 can further verify that the curb height is within the capabilities of the wheelchair. The computing device 1000 can then display the proposed paths on the display device 1011 (optionally, providing a recommended option).
  • the computing device can receive, from the user, an input confirming a proposed path or a selection from the alternatives of the proposed paths. Upon receiving said user input, the computing device can control movement of the actuator.
  • the wheelchair can receive, from the user, an input device (e.g., via a joystick), allowing the user to move the wheelchair forward along the path, reverse movement along the path, or pause movement along the path.
  • feedback from the speed sensors 110 can be used in maintaining desired speeds of the wheelchair as it ascends or descends curbs. That is, the speed sensors can be used in speed control. For example, in curb climbing/descending, speed control can be used in approaching the curb to inhibit collision with, or falling over, the curb. The speed control can further be used to slowly rotate the drive wheels as the drive wheels contact the curb to draw the wheelchair forwardly upon contact. The speed control can further be used to move the wheelchair forwardly once the wheelchair has ascended/descended the curb.
  • the wheelchair as disclosed herein can provide several advantages over conventional powered wheelchairs.
  • the wheelchair as disclosed herein can sense ground reaction forces exerted on the wheels (e.g., the caster wheels and the drive wheels).
  • each of the wheels can be in engagement with the ground, and the total ground reaction forces, can be summed to determine the total ground reaction force between the wheelchair and the ground.
  • the wheelchair can determine a center of mass of both the wheelchair and the user, collectively.
  • the wheelchair can determine the orientation
  • the wheelchair can comprise passive shock absorbers that suppress small perturbations of the wheels for a more comfortable ride than conventional wheelchairs.
  • the wheelchair can comprise actively controlled actuators that are configured to adjust the position of the wheels of the wheelchair, and said actively controlled actuators can enable negotiation of large obstacles, such as, for example, curbs, slopes, cross-slopes, speed bumps, and potholes.
  • the passive shock absorbers can be in series with the actively controlled actuators.
  • the wheelchair can comprise a compliment of sensors that can include, for example, one or more of the following: ground-reaction force sensor(s), wheel/caster position sensor(s), seat/frame orientation sensor(s), seat/frame position sensor(s), seat/frame acceleration (i.e., vibration) sensor(s), machine vision (e.g., cameras, laser range finder, and RADAR) sensor(s), and/or wheel speed/acceleration sensor(s).
  • ground-reaction force sensor(s) wheel/caster position sensor(s), seat/frame orientation sensor(s), seat/frame position sensor(s), seat/frame acceleration (i.e., vibration) sensor(s), machine vision (e.g., cameras, laser range finder, and RADAR) sensor(s), and/or wheel speed/acceleration sensor(s).
  • the wheelchair can further include a distributed control system (e.g., a computing device) that regulates the seat orientation and attitude, performs obstacle detection and classification, path planning with flexible execution (e.g., path planning for curb climbing is statically stable and reversible at any point along the execution path).
  • a distributed control system e.g., a computing device
  • path planning with flexible execution e.g., path planning for curb climbing is statically stable and reversible at any point along the execution path.
  • FIG. 10 shows a system 1000 including an exemplary configuration of a computing device 1001 for use with the wheelchair 10.
  • the computing device 1001 can be integral to the wheelchair 10.
  • a separate computing device such as, for example, a tablet, smartphone, laptop, or desktop computer can communicate with the wheelchair 10 and can enable the user to interface with the wheelchair 10.
  • the computing device 1001 may comprise one or more processors 1003, a system memory 1012, and a bus 1013 that couples various components of the computing device 1001 including the one or more processors 1003 to the system memory 1012. In the case of multiple processors 1003, the computing device 1001 may utilize parallel computing.
  • the bus 1013 may comprise one or more of several possible types of bus structures, such as a memory bus, memory controller, a peripheral bus, an accelerated graphics port, and a processor or local bus using any of a variety of bus architectures.
  • the computing device 1001 may operate on and/or comprise a variety of computer readable media (e g., non-transitory).
  • Computer readable media may be any available media that is accessible by the computing device 1001 and comprises, non-transitory, volatile and/or non-volatile media, removable and non-removable media.
  • the system memory 1012 has computer readable media in the form of volatile memory, such as random access memory (RAM), and/or non-volatile memory, such as read only memory (ROM).
  • the system memory 1012 may store data such as sensor data 1007 (i.e., data from signals received by the electrodes) and/or program modules such as operating system 1005 and center of mass determination software 1006 that are accessible to and/or are operated on by the one or more processors 1003.
  • sensor data 1007 i.e., data from signals received by the electrodes
  • program modules such as operating system 1005 and center of mass determination software 1006 that are accessible to and/or are operated on by the one or more processors 1003.
  • the computing device 1001 may also comprise other removable/non-removable, volatile/non-volatile computer storage media.
  • the mass storage device 1004 may provide non-volatile storage of computer code, computer readable instructions, data structures, program modules, and other data for the computing device 1001.
  • the mass storage device 1004 may be a hard disk, a removable magnetic disk, a removable optical disk, magnetic cassettes or other magnetic storage devices, flash memory cards, CD-ROM, digital versatile disks (DVD) or other optical storage, random access memories (RAM), read only memories (ROM), electrically erasable programmable read-only memory (EEPROM), and the like.
  • Any number of program modules may be stored on the mass storage device 1004.
  • An operating system 1005 and center of mass determination software 1006 may be stored on the mass storage device 1004.
  • One or more of the operating system 1005 and center of mass determination software 1006 (or some combination thereof) may comprise program modules and the center of mass determination software 1006.
  • Sensor data 1007 may also be stored on the mass storage device 1004.
  • Sensor data 1007 may be stored in any of one or more databases known in the art. The databases may be centralized or distributed across multiple locations within the network 1015.
  • a user may enter commands and information into the computing device 1001 using an input device (or plurality of input devices 1016, as illustrated in FIG. 18, comprising a
  • Such input devices can comprise, but are not limited to, a joystick, a touchscreen display, a keyboard, a pointing device (e.g., a computer mouse, remote control), a microphone, a scanner, tactile input devices such as gloves, and other body coverings, motion sensor, speech recognition, and the like.
  • a human machine interface 1002 that is coupled to the bus 1013, but may be connected by other interface and bus structures, such as a parallel port, game port, an IEEE 1394 Port (also known as a Firewire port), a serial port, network adapter 1008, and/or a universal serial bus (USB).
  • a display device 1011 may also be connected to the bus 1013 using an interface, such as a display adapter 1009. It is contemplated that the computing device 1001 may have more than one display adapter 1009 and the computing device 1001 may have more than one display device 1011.
  • a display device 1011 may be a monitor, an LCD (Liquid Crystal Display), light emitting diode (LED) display, television, smart lens, smart glass, and / or a projector.
  • other output peripheral devices may comprise components such as speakers (not shown) and a printer (not shown) which may be connected to the computing device 1001 using Input/Output Interface 1010.
  • Any step and/or result of the methods may be output (or caused to be output) in any form to an output device.
  • Such output may be any form of visual representation, including, but not limited to, textual, graphical, animation, audio, tactile, and the like.
  • the display 1011 and computing device 1001 may be part of one device, or separate devices.
  • the computing device 1001 may operate in a networked environment using logical connections to one or more remote computing devices 1014a,b,c.
  • a remote computing device 1014a, b,c may be a personal computer, computing station (e.g., workstation), portable computer (e.g., laptop, mobile phone, tablet device), smart device (e.g., smartphone, smart watch, activity tracker, smart apparel, smart accessory), security and/or monitoring device, a server, a router, a network computer, a peer device, edge device or other common network node, and so on.
  • Logical connections between the computing device 1001 and a remote computing device 1014a, b,c may be made using a network 1015, such as a local area network (LAN) and/or a general wide area network (WAN), or a Cloud-based network. Such network connections may be through a network adapter 1008.
  • a network adapter 1008 may be implemented in both wired and wireless environments. Such networking environments are conventional and commonplace in dwellings, offices, enterprise-wide computer networks,
  • remote computing devices 1014a,b,c can optionally have some or all of the components disclosed as being part of computing device 1001.
  • some or all aspects of data processing described herein can be performed via cloud computing on one or more servers or other remote computing devices. Accordingly, at least a portion of the system 1000 can be configured with internet connectivity.
  • the user can control general movement of the wheelchair with the joystick, and the user can, via the touchscreen, toggle specific commands, such as raising up, lowering down, tilting forward, tilting backward, tilting left, tilting right, moving the carriage forward, or moving the carriage backward.
  • the touch screen can further enable the user to execute more advanced features such as automated navigation and obstacle traversing.
  • the driving mechanism of an exemplary wheelchair comprises two drive wheels operated by ajoystick R-NET controller (Curtiss-Wright Corp., Cheswick, PA, USA), while the driving wheel carriage is controlled by two DC motors (Dumore Corp., Mauston, WI, USA) to adjust its drive-wheel configuration.
  • Both drive wheel systems are equipped with incremental encoders (US-Digital, Vancouver, WA, USA) to monitor the drive wheels’ speed, acceleration, and translation with relation to the frame.
  • Built-in position sensors measured the pneumatics’ movement, which were translated to wheel height.
  • a nine-degree-of-freedom inertial measurement unit (Adafruit, New York, NY, USA) was mounted under the seat to monitor stability of the exemplary wheelchair (pitch and roll angles).
  • the multiple sensors were fed into an embedded system (Raspberry PI Foundation, Cambridge, U.K.) to control the height of each wheel and perform the control curb negotiation process.
  • a semiautomatic curb negotiation application was created based upon electric powered wheelchair (EPW) user feedback.
  • EW electric powered wheelchair
  • switch 5 can be a three-position switch, having positions corresponding to forward, pause, and reverse.
  • Inclusion criteria for participants were 18 years or older, weighed less than 113.4 kg (250 lb), had at least one year of experience using an EPW, and were able to tolerate sitting for 3 h. Participants with active pressure sores and/or back, pelvic, or thigh pain were excluded. The study was conducted at the National Veterans Wheelchair Games held in Orlando, Florida, and at the Human Engineering Research Laboratories in Pittsburgh, PA, USA. The study was approved by the Veterans Affairs Pittsburgh Healthcare System Institutional Review Boards (ID: PRO02495).
  • Participants were first briefed and consented about the study and then screened to meet the eligibility criteria. After consent, participants completed a demographics questionnaire and information about their own EPWs. Then, participants received training on the exemplary wheelchair’s features and the curb negotiation application. During training, participants ascended and descended curbs a minimum of two times; the training continued until participants and researchers felt comfortable using the exemplary wheelchair. The training lasted approximately 15 min.
  • AASHTO American Association of State Highway and Transportation Officials
  • Effectiveness was defined as how well the device accomplished the given tasks. Quantitative driving metrics, such as task completion time (seconds) and maximum/minimum changes in seat angle (pitch and roll angles), were collected to evaluate the exemplary wheelchair’s performance. These metrics were recorded to demonstrate design objectives D1 and D2.
  • the SUS questionnaire measures the usability of a device to perform tasks.
  • the questionnaire includes ten questions rated at a five-point Likert scale, 1 — “Strongly Disagree” to 5 — “Strongly Agree”.
  • the overall score ranges from 0 to 100, in which a SUS score of 69 is considered an acceptable score of usability among different studies.
  • Each assessment tool included a comment section in each subscale, in which participants could describe their responses toward the exemplary wheelchair and its curb negotiation application.
  • Demographics and categorical metrics such as completion time and angle deviations, were described in means and standard deviation (SD), whereas perception metrics, such as the NASA-TLX and SUS subscores, were described in interquartile (IQR 1- 3), medians, and box plots. The average and SD completion time to ascend and descend curbs
  • E-H actuators are recommended due to fast response time and linear control.
  • E-H actuators are popular in quadruped legged robots that traverse unknown environments due to their lifting capabilities, ease of control, and fast movement. These actuators provide similar lifting capabilities to the
  • E-H actuators Kaman Fluid, Pittsburgh, PA, USA are powered by batteries, which eliminates the need for an air supply.
  • GUI graphical user interface
  • the research offers a sensory system using Intel RealSense (Santa Clara, CA, USA) cameras that identifies curb characteristics for path planning prior ascending or descending curbs. Additionally, the sensory system offers a GUI to display the curb height or curb drop when the user requests to ascend or descend the curb, respectively.
  • One participant recommended the use of padding in the switches because they were uncomfortable. All participants showed dexterity to operate the interface, people with less upper range of motion may require alternative interfaces, which is possible with the exemplary wheelchair.
  • the use of a GUI reiterates the need of customizable options to select different applications.
  • the proposed study highlighted the need to ascend and descend curbs standardized by the AASHTO that commercial EPWs are unable to climb and accessibility to points of interests where ADA guidelines are not met.
  • the results of this study provide novel evidence of usability of robotic wheelchairs for obstacle negotiation with end-users using standardized quantitative and qualitative metrics.
  • the study contributes to the literature by outlining requirements of robotic wheelchairs to address user needs when facing less accessible environments.
  • An exemplary w'heelchair comprises six independently height-adjustable wheels with a modular drive-wheel configuration, omni-wheels as caster wheels to eliminate swivel, and a footprint comparable to that of commercially available EPWs.
  • Each wheel was linked to an active suspension (AS) system that included an adjustable pneumatic shock absorber and an electro-hydraulic motor in series (FIG. 14A).
  • AS active suspension
  • Shock absorbers provided a passive suspension to reduce vibration on uneven surfaces similar to EPWs; while electro-hydraulics were automatically controlled to maintain stability when surface irregularities (e.g., inclined surfaces) were detected.
  • electro-hydraulics can reduce whole body vibrations (WBV) in conjunction with shock absorbers when driving on surfaces transitions that combine an inclined surface with a threshold.
  • WBV whole body vibrations
  • No AS refers to the exemplary wheelchair with inhibited electro-hydraulic actuators and is only reliant on its shock absorbers.
  • the shock absorbers were air-pressured, adjustable, and set at 100 psi per wheel.
  • the selected commercial EPW was the Permobil F5 Corpus, a front-wheel-drive EPW with shock absorbers (FIG. 14B) in each wheel to ameliorate WBV exposure.
  • EPWs with a front-wheel-drive configuration assist with obstacle climbing, stability, and traction outdoors. Both EPWs used an R-Net controller to configure the same driving parameters (i.e., speed and acceleration).
  • the Shimmer 3 triaxial accelerometer (Shimmer, Boston, MA, USA) was mounted in the seat pan of each EPW with its z+ axis facing orthogonal to the seat.
  • the accelerometer incorporates a stand-alone microcontroller (STMicro LSM303AHTR) with a 14-bit resolution, high sensitivity (to detect +/ -8 g), and at a sampling frequency of 100 Hz.
  • the sampling frequency was selected in order to identify a suitable range of frequencies between 0.01 and 80 Hz according to the ISO 2631:1 standard.
  • Similar studies acquired vibration data through accelerometers at a sampling frequency between 50 and 102 Hz.
  • the sensor was validated for use in human health monitoring, monitoring activities of daily living, and environmental and habitat monitoring.
  • a 50th percentile Hybrid II anthropometric dummy of 100 kg was used to simulate a person seated in each EPW. Three trials were performed by driving each EPW on five selected surfaces for a total of 45 trials. Each EPW was controlled remotely by a researcher. The wheelchair speed was set to 1.2 m/s, which is the same as an average person's speed when walking across the street 127]
  • a MATLAB Graphical User Interface (GUI) was developed to measure the time-series accelerations in real-time during the completion of each trial. The GUI facilitated data collection by connecting to the accelerometer, recording data, and saving the data to a custom filename.
  • FIG. 15C 30 and 18.3 cm/m
  • FIG. 15D a series of potholes of up to 30.5 cm in diameter and 5.0 cm in depth
  • the 10° slope simulated conventional incline and decline ramps considered worst-case scenarios for wheelchair dynamic stability as part of the ANSI/RESNA wheelchair standards ISO 7176-2.
  • FIG. 15A shows an Up-Flat-Down 10° Ramp
  • FIG. 15B shows an Up-Flat-Down 10° Ramp with a 2.5 cm threshold in transition
  • FIG. 15C shows Surface roughness with adaptable slabs
  • FIG. 15D shows Potholes of 5.4 cm in depth.
  • Descriptive analysis e.g., means, standard deviation
  • a Totd (kx ⁇ x + ky y i k i) where T is the duration of the trials.
  • Results show no significant differences in average WBV (RMS and VDV) values between the commercial EPW, the exemplary wheelchair with AS, and the exemplary wheelchair with no AS when driving on surface transitions with different thresholds (FIG. 16).
  • FIG. 17 illustrates RMS total acceleration (Top) and VDV (Bottom) differences between surfaces with each EPW. Significant differences between surfaces are denoted with an asterisk (* p-value ⁇ 0.01 post-hoc Bonferrom correction).
  • the Permobil F5 is a high-end EPW with a front- wheel-drive configuration and all-terrain wheels designed to traverse environments with a threshold of up to 3.0 in. in height, according to the manufacturer.
  • the availability of high-end EPWs as such depends on the user's level of impairment and insurance coverage.
  • Alternative cost-effective EPWs have less weight for easier transportation but are limited to fewer seating features and less efficient drive motors.
  • the suspension dampening required to ameliorate WBV effects, particularly on these surfaces, is unknown. Further evaluation of WBV effects on EPWs is encouraged to reduce EPW users' discomfort on surfaces with thresholds.
  • the exemplary wheelchair’s EPW with active suspension was introduced in this study as an alternative suspension mechanism that combines a shock absorber and an electro- hydraulic actuator in series. There were no significant RMS differences between surface thresholds whether using the exemplary wheelchair with or without the AS mechanism. The vibration for each surface remained below 1.2 m/s 2 expect for potholes and the 10° ramp with a 2.5 cm threshold. These results demonstrated that the exemplary wheelchair can reduce the vibration with the use of shock absorbers alone; on the other hand, the use of actuators in the exemplar wheelchair for active suspension remains important to maintain stability on inclined and uneven surfaces to reduce tips and falls.
  • EPWs serve as a means of mobility for users to commute from home to work/school/shops, particularly when public or private transportation is not available or accessible.
  • the typical EPW user can drive at least 1 h/day assuming a normal speed of 1 m/s between locations. During travel, EPW users may drive on
  • FIG. 16 shows high WBV variance in the exemplary wheelchair with AS and no AS across all surfaces.
  • a possible cause is the low dampening settings of the shock absorbers, which caused a high degree of displacement of its suspension.
  • a delay in the activation of the legged-wheel actuators in the AS system may have caused the EPW to replicate the surface profile, causing a bounce effect.
  • the WBV variance in the EPW was only noticeable when driving on the surface with 5.0 cm potholes.
  • crash dummy also plays a passive role compared with a real end-user who may intentionally correct his/her posture and, hence, reducing the WBV variance.
  • the active suspension of the exemplary wheelchair did not reduce nor increase the vibration effects when traversing surface thresholds.
  • the exemplary wheelchair’s active suspension was designed to prevent tips and falls when driving on inclined surfaces by adjusting its legged-wheel actuators in the base.
  • the goal of the shock absorbers was to serve as a form of passive suspension to reduce vibration. The results only demonstrated that its actuators can be inhibited when driving on surfaces with thresholds to improve power consumption while prioritizing shock absorbers in these surface conditions.
  • the commercial EPW used had a front- wheel-drive configuration that is mostly used for active wheelchair users in the community.
  • WBVs may have different effects on EPW users.
  • mid-wheel drive provides high stability on flat surfaces and a small turning radius, but it is at risk of getting stuck on small thresholds and ramps.
  • Rear- wheel drive is a less common in EPWs and mostly used outdoors due to its fast speed but it is prone to tipping as its center of mass is located towards the back and its front wheels may be smaller than the suggested ADA thresholds.
  • EPW users were not recruited for the study to avoid WBV exposure.
  • a crash test dummy was used to prevent discomfort to end-users and for safety when operating the EPWs on challenging surfaces. Additionally, using a crash test dummy provided control over other factors that may influence the vibration exposure, such as weight shifting, repositioning, and weight distribution, commonly encountered with end-users.
  • EPW users can provide feedback in terms of health and comfort when exposed to the vibration levels on surface transitions. Their feedback is important to be able to offer the most adequate mobility assistive device to reduce WBV exposure. Further studies may include subject testing to evaluate the feasibility of EPW suspensions.
  • This study aimed to explore the WBV effects in EPWs when encountering challenging surfaces. While many studies have evaluated vibration in manual wheelchairs, there are few studies that evaluate the vibration effects in EPWs, particularly on surfaces with thresholds that end-users are exposed to daily. This is the first study to evaluate EPW suspensions on surfaces with different thresholds (heights) such as uneven sidewalks and curb-ramps that are not ADA-compliant. Likewise, this is the first study to compare two types of EPW suspension systems (passive and active suspension) to reduce WBV measures on the selected surfaces. The study introduced a novel EPW with active suspension to increase stability and the user's comfort.
  • EPW suspension systems should include end-users to obtain their perception of comfort and health with respect to the WBV exposure in every day environments.
  • a wheelchair comprising: a seat; a frame coupled to the seat; a plurality of wheel assemblies, each wheel assembly comprising: a swing arm that is pivotably coupled to the frame; a wheel rotatably coupled to the swing arm about a respective rotational axis; an actuator system that is configured to adjust the position of the wheel relative to the frame, wherein the actuator system comprises: an actively controlled actuator; and a passive shock absorber arranged in series with the actively controlled actuator; a force sensor that is configured to provide an output associated with a ground force applied by the ground to the wheel; a position sensor that is configured to provide an output associated with a position of the wheel; a memory storing therein at least one center of mass threshold; at least one processor in communication with the memory and in communication with the force sensor and the position sensor of each wheel assembly, wherein the at least one processor is configured to:
  • Aspect 2 The wheelchair of aspect 1, wherein the at least one processor is configured to inhibit the actuator of each wheel assembly of the plurality of wheel assemblies from actuating.
  • Aspect 3 The wheelchair of aspect 1 or aspect 2, wherein the at least one center of mass threshold comprises a forward seat pitch, a rearward seat pitch, a left seat roll, a right seat roll, or combinations thereof.
  • Aspect 4 The wheelchair of any one of aspects 1-3, wherein at least one wheel assembly of the plurality of w heel assemblies is a caster wheel assembly, wherein the wheel of the caster wheel assembly is freely rotatable about the respective rotational axis.
  • Aspect 5 The wheelchair of aspect 4, wherein the wheel of the caster wheel assembly is coupled to the swing arm via a torsion joint, wherein the torsion joint is configured to enable pivotal movement of the wheel of the caster wheel assembly relative to a longitudinal axis that extends between a front and a rear of the wheelchair.
  • Aspect 6 The wheelchair of aspect 4 or aspect 5, wherein only one wheel assembly of the plurality of wheel assemblies is a caster wheel assembly.
  • Aspect 7 The wheelchair of any one of the preceding aspects, wherein the center of mass of the wheelchair accounts for a weight of a user in the seat of the wheelchair.
  • Aspect 8 The wheelchair of any one of the preceding aspects, wherein the actively controlled actuator of the actuator system of at least one wheel assembly of the plurality of wheel assemblies comprises a piston rod that is movable in a first direction, wherein movement of the piston rod in the first direction causes movement of the passive shock
  • Aspect 9 The wheelchair of any one of the preceding aspects, wherein the passive shock absorber is a linear shock absorber actuator having a first end and a second end that is axially movable relative to the first end.
  • the passive shock absorber is a linear shock absorber actuator having a first end and a second end that is axially movable relative to the first end.
  • Aspect 10 The wheelchair of any one of the preceding aspects, wherein the actively controlled actuator comprises an electrohydraulic cylinder and a piston rod that moves axially along the electrohydraulic cylinder.
  • Aspect 11 The wheelchair of aspect 10, wherein the piston rod that moves axially along the electrohydraulic cylinder along a first axis, wherein the passive shock absorber is a linear shock absorber actuator having a first end and a second end that is axially movable relative to the first end along a second axis, wherein the first axis is within 15 degrees of parallel to the second axis.
  • the passive shock absorber is a linear shock absorber actuator having a first end and a second end that is axially movable relative to the first end along a second axis, wherein the first axis is within 15 degrees of parallel to the second axis.
  • Aspect 12 The wheelchair of any one of the preceding aspects, wherein the position sensor of each wheel assembly of the plurality of wheel assemblies is a rotational position sensor that is configured to provide an output based on a rotational position of the respective swing arm of the wheel assembly of the plurality of wheel assemblies.
  • Aspect 13 The wheelchair of any one of the preceding aspects, further comprising an acceleration sensor that is configured to detect vibration amplitude, wherein the acceleration sensor is in communication with the at least one processor, wherein the at least one processor is configured to cease adjustment of the center of mass of the wheelchair if the center of mass is within the threshold and the vibration amplitude is above a vibration threshold.
  • Aspect 14 The wheelchair of any one of the preceding aspects, further comprising a machine vision sensor in communication with the at least one processor, wherein the at least one processor is configured to modify a path of the wheelchair based on the machine visions sensor detecting an object.
  • Aspect 15 The wheelchair of any one of the preceding aspects, further comprising a speed sensor in communication with the at least one processor, wherein the processor is
  • Aspect 16 The wheelchair of any one of the preceding aspects, wherein the passive shock absorber of the actuator system of at least one wheel assembly of the plurality of wheel assemblies is configured to adjust a dampening impedance based on a proximity of the center of mass to the at least one threshold.
  • Aspect 17 The wheelchair of any one of the preceding aspects, wherein the passive shock absorber of the actuator system of at least one wheel assembly of the plurality of wheel assemblies is configured lock based on a proximity of the center of mass to the at least one threshold.
  • Aspect 18 The wheelchair of any one of the preceding aspects, wherein the at least one processor is configured to determine a future center of mass based on a current center of mass of the wheelchair and an angular trajectory of the frame.
  • Aspect 19 The wheelchair of any one of the preceding aspects, further comprising an output device, wherein the at least one processor is configured to determine a weight of a user in the wheelchair, and cause the output device to output the weight of the user.
  • a wheelchair comprising: a seat; a frame coupled to the seat; a plurality of wheel assemblies, each wheel assembly comprising: a swing arm that is pivotably coupled to the frame; a wheel rotatably coupled to the swing arm about a respective rotational axis; an actuator system that is configured to adjust the position of the wheel relative to the frame, wherein the actuator system comprises: an actively controlled actuator; and a passive shock absorber arranged in series with the actively controlled actuator.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)

Abstract

L'invention concerne un fauteuil roulant comprenant un cadre accouplé à un siège et une pluralité d'ensembles roues. Chaque ensemble roue peut comprendre un bras oscillant qui est accouplé en pivotement au cadre, une roue accouplée en rotation au bras oscillant autour d'un axe de rotation respectif et un système actionneur qui est conçu pour ajuster la position de la roue par rapport au cadre. Le système actionneur peut comprendre un actionneur à commande active et un amortisseur passif disposé en série avec l'actionneur à commande active.
PCT/US2022/029196 2021-05-14 2022-05-13 Fauteuil roulant à actionnement de suspension passif-actif à axes multiples WO2022241218A1 (fr)

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US63/188,591 2021-05-14

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US20230255141A1 (en) * 2022-02-15 2023-08-17 Cnh Industrial America Llc Systems and methods for monitoring the operational status of passive lift suppports and related work machines

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US3618968A (en) * 1969-05-01 1971-11-09 Edward M Greer Patient-operated wheelchair
WO1996023478A1 (fr) * 1995-02-03 1996-08-08 Deka Products Limited Partnership Vehicules et procedes de transport
US20050178590A1 (en) * 2004-02-13 2005-08-18 Martin-Woodin Audrey K. Weight measurement and support apparatus for a human and method of use
US20070194550A1 (en) * 2006-02-22 2007-08-23 Frank Wadelton Vehicle Wheel Suspension System
US20090045598A1 (en) * 2005-05-10 2009-02-19 Seung Youl Lee Skateboard capable of all-direction running
US20190290514A1 (en) * 2016-10-21 2019-09-26 Airbus Defence And Space Limited Vehicle wheel assembly
CN210330937U (zh) * 2019-05-17 2020-04-17 台州职业技术学院 一种基于机器视觉的智能轮椅
US20200121526A1 (en) * 2015-09-25 2020-04-23 University of Pittsburgh -Of The Commonwealth System of Higer Education Mobility enhancement wheelchair

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3618968A (en) * 1969-05-01 1971-11-09 Edward M Greer Patient-operated wheelchair
WO1996023478A1 (fr) * 1995-02-03 1996-08-08 Deka Products Limited Partnership Vehicules et procedes de transport
US20050178590A1 (en) * 2004-02-13 2005-08-18 Martin-Woodin Audrey K. Weight measurement and support apparatus for a human and method of use
US20090045598A1 (en) * 2005-05-10 2009-02-19 Seung Youl Lee Skateboard capable of all-direction running
US20070194550A1 (en) * 2006-02-22 2007-08-23 Frank Wadelton Vehicle Wheel Suspension System
US20200121526A1 (en) * 2015-09-25 2020-04-23 University of Pittsburgh -Of The Commonwealth System of Higer Education Mobility enhancement wheelchair
US20190290514A1 (en) * 2016-10-21 2019-09-26 Airbus Defence And Space Limited Vehicle wheel assembly
CN210330937U (zh) * 2019-05-17 2020-04-17 台州职业技术学院 一种基于机器视觉的智能轮椅

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20230255141A1 (en) * 2022-02-15 2023-08-17 Cnh Industrial America Llc Systems and methods for monitoring the operational status of passive lift suppports and related work machines

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