Search

EP-4190644-B1 - GROUND VEHICLE BUMPER SYSTEM

EP4190644B1EP 4190644 B1EP4190644 B1EP 4190644B1EP-4190644-B1

Inventors

  • WORDEN, NATHANAEL ARLING
  • HECTOR, MICHAEL JOHN

Dates

Publication Date
20260513
Application Date
20220805

Claims (7)

  1. A vehicle (100) comprising: a body (102, 102a) having a first outer periphery (122a) in a first plane that is parallel to a surface on which the vehicle (100) moves in a horizontal direction; a bumper assembly (110, 110a, 310) having a second outer periphery (124a) in a second plane parallel to the first plane, the second outer periphery (124a) including portions that extend beyond the first outer periphery (122a) in the horizontal direction; one or more flexible couplings (120, 120a, 320) coupling the bumper assembly (110, 110a, 310) to the body (102, 102a), the one or more flexible couplings (120, 120a, 320) allowing for horizontal planar deflection of the bumper assembly (110, 110a, 310) relative to the body (102, 102a) when the bumper assembly (110, 110a, 310) impacts an obstacle when the vehicle (100) is moving in the horizontal direction; wherein each of the one or more flexible couplings (120, 120a, 320) comprise an extension spring (320, 410), an axis of the extension spring (320, 410) extending in a direction orthogonal to the horizontal direction when the extension spring is in a neutral position, and wherein a first end (312) of the extension spring (320, 410) is coupled to the bumper assembly (110, 110a, 310) and a second end (314) of the extension spring (320, 410) is coupled to the body (102, 102a), characterized in that when the bumper assembly is in horizontal planar deflection, the extension spring is bended and provides restorative force in the horizontal direction; one or more sensors (360a, 360b) mounted relative to the bumper assembly (110, 110a, 310) and to the body (102, 102a) to detect horizontal planar deflection of the bumper assembly (110, 110a, 310), the one or more sensors (360a, 360b) being configured to generate signals indicating the bumper assembly (110, 110a, 310) has deflected in the horizontal planar direction at least a threshold amount; and a drive system configured to propel the vehicle (100) in the horizontal direction and that receives, as input, the signals generated by the one or more sensors (360a, 360b) and in response to the signals indicating the bumper assembly (110, 110a, 310) has deflected in the horizontal planar direction at least a threshold amount, causes the vehicle (100) to stop moving in the horizontal planar direction.
  2. The vehicle (100) of claim 1, wherein the one or more sensors (360a, 360b) each comprise a proximity sensor, and, wherein optionally: a sensing face of the proximity sensor is mounted to the body (102, 102a); and a target of the proximity sensor is mounted to the bumper assembly (110, 110a, 310) so that the sensing face and target are in operative disposition from each other.
  3. The vehicle (100) of claim 2, wherein when the target is not within a specified proximity to the sensing face, the proximity sensor generates the signals indicating the bumper assembly (110, 110a, 310) has deflected in the horizontal planar direction at least a threshold amount.
  4. The vehicle (100) of any one of claims 1 to 3, wherein each of the one or more flexible couplings (120, 120a, 320) are in the neutral position in the horizontal direction when the bumper assembly (110, 110a, 310) is not in horizontal planar deflection, and apply the restorative force when the bumper assembly (110, 110a, 310) is in horizontal planar deflection that causes the bumper assembly (110, 110a, 310) to force toward the neutral position.
  5. The vehicle (100) of any one of claims 1 to 4, wherein the one or more flexible couplings (120, 120a, 320) allows for vertical deflection of the bumper assembly (110, 110a, 310) relative to the body (102, 102a), and wherein optionally the one or more flexible couplings (120, 120a, 320) each apply a restorative force to the bumper assembly (110, 110a, 310) in the vertical direction, the restorative force causing the bumper assembly (110, 110a, 310) to return to a neutral vertical position after a vertical deflection.
  6. The vehicle (100) of claim 1, wherein the first end (312) of the extension spring (320, 410) is coupled to a horizontal surface of the bumper assembly (110, 110a, 310) by a threaded plug (420).
  7. The vehicle (100) of any one of claims 1 to 6, wherein the vehicle (100) comprises an autonomous ground vehicle.

Description

TECHNICAL FIELD This specification relates generally to safety systems for automatic guided vehicles. BACKGROUND Automatic Guided Vehicle (AGV) systems use various obstacle detection devices, such as collapsible contact bumpers. These bumpers are instrumented to trigger a safety stop if they collide with an obstacle. If an AGV collides with an object, the safety stop can prevent or mitigate damage to the AGV and the obstacle. Bumper activation causes a safety stop within the collapsible range of the bumper and before the vehicle strikes the obstacle. Collapsible contact bumpers typically have large radii and/or edges with shallow angles, and are challenging to integrate into AGVs with rounded or complex shapes. US 4 397 372 A discloses bumper systems for use with automatically controlled, self-propelled vehicles to prevent damage to the vehicle and other obstacles. CN 106 427 444 A discloses a kind of robot chassis. TW 201 127 683 A discloses a storage rack used for a bike. US 2019/155277 A1 discloses an autonomous vehicle according to the preamble of claim 1. SUMMARY The claimed subject-matter is defined in the independent claim. Dependent claims describe embodiments thereof. Disclosed are systems for ground vehicle bumper systems. The disclosed systems can be implemented to detect collisions of ground vehicles, such as AGVs, by sensing the motion of a bumper mounted to a frame of the vehicle body. The bumper is a single rigid bumper mounted to the frame via a compliant mechanism. The single bumper deflects upon experiencing a collision, and springs back to a neutral position after being deflected. The disclosed system can be used to reduce the likelihood of damage to vehicles and obstacles. Deflection of the bumper can be monitored by sensors and a controller. The sensors can be configured to detect deflection of the bumper and output signals to the controller indicating the deflection. The controller can stop movement of the vehicle in response to receiving the signals. The controller can stop movement of the vehicle by outputting a vehicle stop command to a drive system of the vehicle. Sensing the motion of a rigid bumper allows for complex shaped bumper edges. The bumper can have any shape, such that at least a portion of the bumper extends beyond the periphery of the vehicle body in the plane of motion of the vehicle. This approach can be used to create an AGV safety bumper that has high flexibility in shape, stiffness, and travel distance. In general, one innovative aspect of the subject matter described in this specification can be embodied in a vehicle including a body having a first outer periphery in a first plane that is parallel to a surface on which the vehicle moves in a horizontal direction; a bumper assembly having a second outer periphery in a second plane parallel to the first plane, the second outer periphery including portions that extend beyond the first outer periphery in the horizontal direction; one or more flexible couplings coupling the bumper assembly to the body, the one or more flexible couplings allowing for horizontal planar deflection of the bumper assembly relative to the body when the bumper assembly impacts an obstacle when the vehicle is moving in the horizontal direction; one or more sensors mounted relative to the bumper assembly and to the body to detect horizontal planar deflection of the bumper assembly, the one or more sensors being configured to generate signals indicating the bumper assembly has deflected in the horizontal planar direction at least a threshold amount; and a drive system configured to propel the vehicle in the horizontal direction and that receives, as input, the signals generated by the one or more sensors and in response to the signals indicating the bumper assembly has deflected in the horizontal planar direction at least a threshold amount, causes the vehicle to stop moving in the horizontal planar direction. The foregoing and other embodiments can each optionally include one or more of the following features, alone or in combination, within the scope of the appended claims. In some implementations, the one or more sensors each include a proximity sensor. In some implementations, a sensing face of the proximity sensor is mounted to the body; and a target of the proximity sensor is mounted to the bumper assembly so that the sensing face and target are in operative disposition from each other. In some implementations, when the target is not within a specified proximity to the sensing face, the proximity sensor generates the signals indicating the bumper assembly has deflected in the horizontal planar direction at least a threshold amount. In some implementations, each of the one or more flexible couplings are in a neutral position in the horizontal direction when the bumper assembly is not in horizontal planar deflection, and apply a restorative force when the bumper assembly is in horizontal planar deflection that causes the bumper assembly to