Patent Publication Number: US-11026551-B2

Title: Suspension system, methods, and applications

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Provisional Patent Application Ser. No. 62/574,255, filed Oct. 19, 2017 and entitled “SUSPENSION SYSTEM, METHODS, AND APPLICATIONS,” the entire disclosure of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present disclosure is directed generally to a vehicle suspension system for a drivable platform; more particularly, to a suspension system for a vacuum cleaner; and, most particularly, to a suspension system for a robotic vacuum cleaner, associated methods, and applications. 
     BACKGROUND 
     Cleaning patterns available to be executed with existing robotic floor cleaners are limited by their architecture, control, sensing and drive systems. Commercial robotic vacuum cleaners such as the Dyson® Eye, the Roomba®, and many of Samsung&#39;s models use a non-holonomic drive system; i.e., the drives use two independently powered wheels and a caster to provide 3-point support for their robotic vacuum cleaners. The two independently powered wheels can be used to move the robot body in a straight line, a curved line, or to spin; however, each of these drive systems are only able to move the robotic vacuum cleaner in a direction that is not perpendicular to the assigned (fixed) orientation of the robotic vacuum cleaner. 
     When non-holonomic robots move, e.g., northerly and then easterly, the robot must drive north, spin 90 degrees to the right, and drive east or, alternatively; they could drive north, rotate 90 degrees to the right while moving forward through an arc, and then drive east. In any case, the non-holonomic drive robotic vacuum cleaner began facing in one direction (e.g., north, south, east, west) and finished facing in a different direction, e.g., (east, west). 
     A robotic vacuum cleaner equipped with a holonomic drive can drive in a given direction, e.g., north (with its assigned orientation being north) and move in a different direction, e.g., east, north-east, or any direction) while maintaining its assigned orientation or that of any desired portion of the robot such as an intake, bank of sensors, or any other portion of the robot that is needed for a particular maneuver. 
     Further, the wheels of a vacuum cleaner need to have a limited amount of movement to overcome small variations in the surface being vacuumed. The wheels of a robotic vacuum cleaner provide propulsion and turning ability to the robotic vacuum cleaner; therefore, it is important that the wheels maintain contact with the floor to maintain control, e.g., allowing it to climb over obstacles such as a door threshold without losing drive or control. 
     Using four ‘Omni’ wheels requires that each wheel be in good contact with the ground for accurate maneuvering. Normally, with a solid chassis, only three points will make ideal contact, which on an ‘Omni’ platform can lead to slippage and incorrect driving characteristics. 
     Accordingly, there is a need in the art for a suspension system for a robotic vacuum cleaner that has an independent suspension system for each wheel assembly to ensure that all the wheels are properly loaded and can properly maneuver the robotic vacuum cleaner. 
     SUMMARY 
     The present disclosure is directed to a robotic vacuum cleaner equipped with a holonomic drive that can drive in a given direction, e.g., north (with its assigned orientation being north) and move in a different direction, e.g., east, north-east, or any direction) while maintaining its assigned orientation or that of any desired portion of the robot such as an intake, bank of sensors, or any other portion of the robot that is needed for a particular maneuver. 
     Moreover, advantages and benefits are realized by a robotic vacuum cleaner (or floor cleaner) having enhanced cleaning and maneuvering capability enabled by an omni-directional and holonomic drive platform exhibiting decoupled rotational and translational degrees of freedom. The advantages of being able to uniquely maneuver a robotic floor cleaner with holonomic drive can be exploited during spot cleaning, cleaning the edges of an area, putting sensors in places they are needed, navigating obstacles, and others that would be recognized by those skilled in the art to realize more efficient cleaning. 
     According to an aspect the present invention is an independent suspension system for a robot vacuum cleaner. The independent suspension system for a robot vacuum cleaner includes a hinge component attached to an L-shaped bracket having a horizontal flange portion and a vertical flange portion. The vertical flange portion is attached to a wheel assembly of the robot vacuum cleaner and a spring is coupled to the horizontal flange portion. A pin is attached to and extends from the vertical flange portion. A holding component is within a wheel well of the robot vacuum cleaner and is movable between an engaged configuration with the pin and a disengaged configuration with the pin. 
     According to an embodiment, wheel assembly is rotatable approximately 180 degrees about the hinge component. 
     According to an embodiment, the spring is one of a leaf spring, a compression spring, and a torsion spring. 
     According to an embodiment, the independent suspension system also includes one or more bumpers attached to at least one of the horizontal flange portion and the vertical flange portion. 
     According to an embodiment, the bumpers are composed of resilient material. 
     According to another aspect, the independent suspension system for a robot vacuum cleaner includes a hinge component attached to an L-shaped bracket. The L-shaped bracket has a horizontal flange portion and a vertical flange portion. The vertical flange portion is attached to a motor pod of the robot vacuum cleaner. The motor pod houses the drive motor and motor controller of the robot vacuum cleaner. A clip is mounted to the motor pod and a suspension pin is mounted between two springs in a spring holster in a wheel well of the robot vacuum cleaner. The motor pod is rotatable about the hinge component between an open position wherein the suspension pin does not engage the clip and a closed position wherein the suspension pin engages the clip. 
     According to an embodiment, gussets extend between the horizontal flange portion and the vertical flange portion of the L-shaped bracket. 
     According to an embodiment, the two springs are compression springs. 
     According to an embodiment, the independent suspension system also includes a receptacle configured for connection to the motor controller. 
     These and other aspects of the invention will be apparent from the embodiments described below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which: 
         FIG. 1  is an exemplary robotic vacuum cleaner having four powered, maneuverable wheel assemblies, comprising the embodied suspension system(s). 
         FIG. 2A  is an underside view of the robotic vacuum cleaner showing one embodied independent suspension system connected to a wheel assembly. 
         FIG. 2B  is a four-wheel suspension system installed on the underside of the robotic platform. 
         FIG. 3  is an exemplary independent suspension system connected to a respective wheel assembly. 
         FIG. 4A  is a wheel well within the vacuum cleaner chassis and a pin holding component. 
         FIG. 4B  is the pin of the suspension system engaging the clip when the wheel bracket assembly is rotated about the hinge into the near horizontal/operational position. 
         FIG. 5A  is a front view of another exemplary independent suspension system connected to a respective motor pod/wheel assembly. 
         FIG. 5B  is a rear view of another exemplary independent suspension system connected to a respective motor pod/wheel assembly. 
         FIG. 6  is a tapered suspension pin, two compression springs, and a spring holster, which are mounted in each wheel well of the robotic platform. 
         FIG. 7  is the springs providing limited, independent up/down movement of each motor pod/wheel assembly. 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Aspects of the present invention and certain features, advantages, and details thereof, are explained more fully below with reference to the non-limiting examples illustrated in the accompanying drawings. Descriptions of well-known structures are omitted so as not to unnecessarily obscure the invention in detail. It should be understood, however, that the detailed description and the specific non-limiting examples, while indicating aspects of the invention, are given by way of illustration only, and are not by way of limitation. Various substitutions, modifications, additions, and/or arrangements, within the spirit and/or scope of the underlying inventive concepts will be apparent to those skilled in the art from this disclosure. 
     An aspect of the invention is a suspension system for a robotic vacuum cleaner. An exemplary robot vacuum cleaner is shown and described in U.S. patent application Ser. No. 16/162,463, the contents of which are hereby incorporated by referenced in their entirety. An embodied suspension system generally includes a hinge, one or more springs, and a holding mechanism. Resilient bumpers and/or a pin may be further included. A suspension assembly may further include a holding component engageable with a pin of the suspension system. A respective independent suspension system is associated with a respective wheel of the robotic vacuum cleaner, thus a robotic vacuum cleaner having four wheels would have four respective independent suspension systems. Such independent suspension systems allow the vacuum cleaner wheels to be pivoted, removed, and cleaned and/or serviced without the need for tools. The embodied suspension system for a robotic vacuum cleaner enables a small amount (e.g., &lt;0.5 inch) of independent movement of the wheels to enable the robot to traverse small bumps or discontinuities in the surface being vacuumed and also allows wheels to be pivoted for removal or replacement. 
     Referring now to the figures, wherein like reference numerals refer to like parts throughout,  FIG. 1  shows an exemplary robotic vacuum cleaner having four powered, maneuverable wheel assemblies, comprising the embodied suspension system(s). The suspension attaches the wheel assemblies to a chassis of the vacuum cleaner. Without compliance only three wheels will be in contact with the floor at any time. The independent suspension of each of the four wheels allows all four wheels to be in contact with the floor to drive and control the robotic vacuum. Though shown with ‘Omni’ or Mecanum wheels, this type of suspension may be used with other types of wheels. 
     Turning now to  FIG. 2A  there is shown an underside view of the robotic vacuum cleaner showing one embodied independent suspension system connected to a wheel assembly. Each of the four suspension systems are attached to the vacuum cleaner chassis through a simple hinge as shown. The hinge allows up and down movement of the wheel. The hinge may be screwed, welded, or otherwise attached to the vacuum cleaner base.  FIG. 2B  schematically illustrates the four-wheel suspension system installed on the underside of the robotic platform. Other embodiments of the suspension system described herein below will similarly attach to the underside of the vacuum cleaner platform. 
     Referring now to  FIG. 3 , there is shown an exemplary independent suspension system  100  connected to a respective wheel assembly. The independent suspension system  100  includes a hinge component  102  attached to an L-shaped bracket  104  characterized by a horizontal flange portion  104 A and a vertical flange portion  104 B. The vertical flange  104 B is attached to the wheel assembly as illustrated. The L-shaped bracket is advantageously made of metal or other suitable material providing sufficient strength, flexibility, durability, and cost effectiveness. 
     Still referring to  FIG. 3 , a simple leaf spring  106  is coupled to the horizontal flange portion  104 A and provides for limited (e.g., up to 0.5 in) resilient up/down movement of the wheel assembly while the robotic vacuum cleaner operationally moves along a floor. The spring  106  can be unique for each wheel to provide balanced support to the robotic vacuum. While a leaf spring  106  is shown, the spring force could also be provided by a compression or torsion spring as one skilled in the art would recognize. When the robotic vacuum cleaner is not in operational use, the hinge component  102  allows the suspension and attached wheel assembly to be swung away from the underside of the vacuum cleaner almost 180 degrees as limited by the wheel diameter, for cleaning, wheel removal, access, etc. 
     As shown in  FIG. 3 , a plurality of (advantageously, four) rubber or other resilient material bumpers  110  may be attached to the horizontal and vertical flanges  104 A,  104 B of the L-bracket  104  substantially as shown. The bumpers  110  cushion the robot when the wheel rolls over a bump or an abrupt surface change, or when the robot is dropped and the brackets  102  the full up/rotated position. The bumpers  110  also dampen the sound of the wheel brackets interacting with the vacuum cleaner housing. A pin  112  may be attached to the vertical flange  104 B. The pin  112 , when engaged with a holding component, described below, is used to limit the movement of the wheel towards the housing when the vacuum cleaner is in operational use.  FIG. 3  shows the pin  112  as a stud threaded into a PEM Nut of the bracket  104 . A simple screw can also be threaded into the PEM Nut and act as the pin  112 . 
     Turning now to  FIG. 4A , there is shown a wheel well within the vacuum cleaner chassis and a pin holding component  115 . As illustrated, the pin holding component  115  is a simple, commercial spring “tool hold” clip. The pin  112  of the suspension system  100  engages the clip  115  when the wheel bracket assembly is rotated about the hinge  102  into the near horizontal/operational position, as illustrated in  FIG. 4B . The pin holding component  115  and pin  112  are configured to allow a limited amount of vertical movement (up to approximately 0.5 in) of the suspension system  100 . 
     In normal operation, the spring  106  pushes the L-bracket  104  downward until the pin  112  reaches the bottom of the holding component  115 . Furthermore, the clip  115 , hinge  102 , and bracket  104  allow the wheel bracket to be pivoted from the clip  115  for service, removal or replacement of the wheel without the need for special tools. The engagement of the pin  112  with the holding component  115  is chosen to provide a low enough force for easy opening and closing of the suspension system  100  (about 1.5 lbs. depending upon materials), while maintaining sufficient force to hold the wheel assembly within the holding component  115  during lifting and normal handling of the robotic vacuum cleaner. Although a commercial “tool holder” spring clip  115  is shown for low cost and commercial availability, various spring clips or custom pin holders are envisioned. 
     Referring now to  FIGS. 5A and 5B , there are shown perspective front and rear views of another exemplary independent suspension system  1000  connected to a respective motor pod/wheel assembly. The system  1000  includes a hinge component  1002  attached to a metal bracket  1003  including a right-angled vertical flange portion  1004 . A plastic motor pod  1090  attaches to the vertical flange of the metal bracket  103 . The motor pod  1090  houses a drive motor and motor controller. Pressed to the motor end is a drive hub and quick connect clip for the wheel. A pod ring of low friction material is pressed about the outer diameter of the motor pod  1090 . The ring provides a low friction, low wear, bearing surface for the wheel. 
     As shown in  FIG. 5B , a receptacle  1008  for plugging to the wheel motor controller is located in the rear of the wheel bracket  1003  on the vertical flange portion  1003 . In the depicted embodiment, the bracket  1003  is shown stiffened with gussets  1009 . A spring steel tool clip  1010  is mounted to the top of the motor pod  1090 . The clip  1010  can be adjusted by tightening or loosening a mounting screw  1011 , which closes/opens the opening of the clip  1010 . The clip  1010  provides a flexible pinching force that can hold the wheel assembly in the closed position or easily be overcome to open the wheel assembly for cleaning or service. 
     Turning now to  FIG. 6 , there is shown a tapered suspension pin  1020 , two compression springs  1022 , and a spring holster  1023 , which are mounted in each wheel well of the robotic platform. As the suspension system  1000  is rotated from an open position to a near horizontal, operational closed position, the suspension pin  1020  engages the spring clip  1010 . Once seated, the springs  1022  provide limited, independent up/down movement of each motor pod/wheel assembly, as schematically illustrated in  FIG. 7 . The wheel bracket  1003  can be opened by rotating the wheel bracket  1003  until the suspension pin  1020  snaps out of the tool clip  1010 . The springs  1022  can be unique for each wheel to provide balanced support to the robotic vacuum. 
     The suspension system  1000  allows the wheel bracket  1003  to be pivoted from the clip  1010  for service, removal, or replacement of the wheel without the need for special tools. The engagement of the pin  1020  with the spring clip  1010  is chosen to provide a low enough force for easy opening and closing of the brackets  1003  (approximately 1.5 lbs.) while maintaining sufficient force to hold the wheel assemblies within the clip  1010  during lifting and normal handling of the robotic vacuum cleaner. A commercial “tool holder” spring clip  1010  is shown for low cost and commercial availability. Hardened springs  1022  provide consistent deflection and force over many cycles. The spring clip  1010  assembly may comprise other types of springs and clips as a person skilled in the art would appreciate. 
     While various embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, embodiments may be practiced otherwise than as specifically described and claimed. Embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the scope of the present disclosure. 
     The above-described embodiments of the described subject matter can be implemented in any of numerous ways. For example, some embodiments may be implemented using hardware, software or a combination thereof. When any aspect of an embodiment is implemented at least in part in software, the software code can be executed on any suitable processor or collection of processors, whether provided in a single device or computer or distributed among multiple devices/computers.