# US 11,077,708 B2 · Mobile robot having an improved suspension system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,077,708 B2 - Document ID: US11077708B2 - Status: Granted - Kind: B2 - Application number: 16/221,865 - Filed: 2018-12-17 - Published: 2019-06-20 - Granted: 2021-08-03 - Earliest claimed: 2017-12-18 - Assignees: Locus Robotics Corp. - Applicants: Locus Robotics Corp. - Inventors: Hian Kai Kwa; Peter Sussman; Michael Sussman - Web page: https://patentgrep.com/patent/US11077708B2 ## CPC - B60B 33/045: {mounted resiliently, by means of dampers} - B25J 5/007: {mounted on wheels} - B25J 19/0091: {Shock absorbers (in general F16F)} - B25J 19/022: {using lasers} - B60G 3/02: with a single pivoted arm - B60G 11/18: having torsion-bar springs only {(B60G11/006 takes precedence; having rubber springs of the torsional-energy-absorption type B60G11/23)} - B62D 21/11: with resilient means for suspension {, e.g. of wheels or engine; sub-frames for mounting engine or suspensions} - B62D 21/18: characterised by the vehicle type and not provided for in groups B62D21/02 - B62D21/17 - B62D 61/04: with two other wheels which are coaxial - B60B 2900/131: Vibrations - B60B: VEHICLE WHEELS (making wheels or wheel parts by rolling B21H1/00, by forging, hammering or pressing B21K1/28); CASTORS; AXLES FOR WHEELS OR CASTORS; INCREASING WHEEL ADHESION - B25J: MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES ({manipulators specially adapted for use in surgery A61B34/70; manipulators used in cleaning hollow articles B08B9/04}; manipulators associated with rolling mills B21B39/20; manipulators associated with forging machines B21J13/10; {manipulators associated with picking-up and placing mechanisms B23P19/007}; means for holding wheels or parts thereof B60B30/00; {vehicles with ground-engaging propulsion means, e.g. walking members B62D57/02, B62D57/032; devices for picking-up and depositing articles or materials between conveyors B65G47/90, B65G47/91; manipulators with gripping or holding means for transferring packages B65H67/065}; cranes B66C; {manipulators used in the protection or supervision of pipe-line installations F17D5/00; walking equipment adapted for nuclear steam-generators F22B37/006}; manipulators specially adapted for, or associated with, nuclear reactors G21C; {apparatus used for handling wafers during manufacture or treatment of semiconductor H10P72/50}) - B60G: VEHICLE SUSPENSION ARRANGEMENTS (air-cushion vehicles B60V; {cycle suspensions B62K25/00}) - B62D: MOTOR VEHICLES; TRAILERS (steering, or guiding on a desired track, of agricultural machines or implements A01B69/00; wheels, castors, axles, increasing wheel adhesion B60B; vehicle tyres, tyre inflation or tyre changing B60C; connections between vehicles of a train or the like B60D; vehicles for use on rail and road, amphibious or convertible vehicles B60F; suspension arrangements B60G; heating, cooling, ventilating or other air treating devices B60H; windows, windscreens, non-fixed roofs, doors or similar devices, protective coverings for vehicles not in use B60J; propulsion plant arrangements, auxiliary drives, transmissions, controls, instrumentation or dashboards B60K; electric equipment or propulsion of electrically-propelled vehicles B60L; power supply for electrically-propelled vehicles B60M; passenger accommodation not otherwise provided for B60N; adaptations for load transportation or to carry special loads or objects B60P; arrangement of signalling or lighting devices, the mounting or supporting thereof or circuits therefor, for vehicles in general B60Q; vehicles, vehicle fittings or vehicle parts not otherwise provided for B60R; servicing, cleaning, repairing, supporting, lifting, or manoeuvring, not otherwise provided for, B60S; brake arrangements, brake control systems or parts thereof B60T; air-cushion vehicles B60V; motor-cycles, accessories therefor B62J, B62K; testing of vehicles G01M) ## Abstract A mobile robot configured to drive on a surface with irregularities, comprising: a chassis having a front end facing a forward direction of travel, a back end, a first side, and a second side. There is a first drive wheel rigidly affixed to the chassis proximate the first side and interconnected to a motor to propel it. There is a second drive wheel rigidly affixed to the chassis proximate the second side and interconnected to a motor to propel it. A first caster assembly is rigidly affixed to the chassis proximate the front end and includes a first caster wheel configured to rotate about a first swivel axis. A second caster assembly is rigidly affixed to the chassis proximate the back end and includes a second caster wheel configured to rotate about a second swivel axis and it includes a compliant member to absorb the irregularities. ## Claims ### Claim 1 A mobile robot configured to drive on a surface with irregularities, comprising: a chassis having a front end facing a forward direction of travel of the mobile robot, a back end, a first side, and a second side; a first drive wheel rigidly affixed to the chassis proximate the first side and interconnected to at least one motor to propel the first drive wheel; a second drive wheel rigidly affixed to the chassis proximate the second side and interconnected to the at least one motor to propel the second drive wheel; a first caster assembly rigidly affixed to the chassis proximate the front end of the chassis; wherein the first caster assembly includes a first swivel mechanism to which a first caster wheel is rotatably affixed via a rigid interconnection member to rotate about a first swivel axis; and a second caster assembly rigidly affixed to the chassis proximate the back end of the chassis; wherein the second caster assembly includes a second swivel mechanism to which a second caster wheel is rotatably affixed via a compliant interconnection member to rotate about a second swivel axis; a laser-radar sensor located proximate the front end of the chassis configured to provide sensor data to a robot controller for navigation of the mobile robot; wherein when the at least one motor propels the first and second drive wheels, thereby causing the mobile robot to drive on the surface, the compliant interconnection member of the second caster assembly absorbing the irregularities in the surface and the rigid interconnection member of the first caster assembly maintaining the front end of the chassis level with the surface to provide a consistent scan plane for the laser-radar sensor. ### Claim 2 (depends on 1) The mobile robot of claim 1 further including a platform supported by the chassis and configured to carry a load. ### Claim 3 (depends on 2) The mobile robot of claim 2 wherein the at least one motor includes a first motor connected to the first drive wheel via a first axle and a second motor connected to the second drive wheel via a second axle, thereby allowing the first and second drive wheels to be propelled independently. ### Claim 4 (depends on 3) The mobile robot of claim 3 wherein the chassis includes a bottom surface having a first cavity in which the first caster assembly is disposed and a second cavity in which the second caster assembly is disposed. ### Claim 5 (depends on 4) The mobile robot of claim 4 wherein the first swivel mechanism is rigidly affixed to a base of the first cavity and the rigid interconnection member includes a bracket which is rotatably connected at a first end to the first swivel mechanism and at a second end of the bracket the first caster wheel is connected. ### Claim 6 (depends on 5) The mobile robot of claim 5 wherein the second swivel mechanism is rigidly affixed to a base of the second cavity and the compliant interconnection member includes a spring which is rotatably connected at a first end to the second swivel mechanism and at a second end of the spring the second caster wheel is connected. ### Claim 7 (depends on 6) The mobile robot of claim 6 wherein the spring is a torque spring. ### Claim 8 (depends on 1) The mobile robot of claim 1 wherein the first and second drive wheels are positioned between the first caster assembly proximate the front end of the chassis and the second caster assembly proximate the back end of the chassis. ### Claim 9 (depends on 1) The mobile robot of claim 1 wherein the second swivel mechanism is affixed to the chassis and wherein the second swivel mechanism is positioned above the compliant interconnection member relative the surface.