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EP-4741261-A1 - OMNIDIRECTIONAL WHEEL ARRANGEMENT

EP4741261A1EP 4741261 A1EP4741261 A1EP 4741261A1EP-4741261-A1

Abstract

An omnidirectional wheel arrangement (1) comprises a first wheel (3a), a second wheel (3b), and a propulsion drive system (7a, 7b, 19, 20, 21, 22) to drive the first wheel (3a) to rotate around a first wheel axis (4a). The wheels (3a, 3b) are rotatable around a first steering axis (6a) and a second steering axis (6b) and a steering drive system (9, 9', 10, 17a, 17b) is configured to rotate the wheels (3a, 3b) around the steering axes (6a, 6b). The second steering axis (6b) is different from and parallel to the first steering axis (6a), the first steering axis (6a) is perpendicular to the first wheel axis (4a), and the second steering axis (6b) is perpendicular to the second wheel axis (4b). The wheels (3a, 3b) are coupled by the steering drive system (9, 9', 10, 17a, 17b) to enforce that the wheel axes (4a, 4b) are parallel.

Inventors

  • Bin Wan Nizar, Wan Muhammad Iqmal
  • Gkekas, Konstantinos
  • Dr. Newrzella, Sebastian
  • ZEIDLER, JOSEF

Assignees

  • Siemens Healthineers AG

Dates

Publication Date
20260513
Application Date
20241108

Claims (15)

  1. Omnidirectional wheel arrangement (1) for a vehicular device (11) wherein - the omnidirectional wheel arrangement (1) comprises a carrier (2) for mounting the omnidirectional wheel arrangement (1) to the vehicular device (11), a first wheel (3a) with a first wheel axis (4a), a second wheel (3b) with a second wheel axis (4b), and a propulsion drive system (7a, 7b, 19, 20, 21, 22), which is configured to drive the first wheel (3a) and the second wheel (3a) individually to rotate around the first wheel axis (4a) and the second wheel axis (4b), respectively; - the first wheel (3a) is mounted to the carrier (2) such that the first wheel (3a) is rotatable around a first steering axis (6a), the second wheel (3b) is mounted to the carrier (2) such that the second wheel (3b) is rotatable around a second steering axis (6b), and the omnidirectional wheel arrangement (1) comprises a steering drive system (9, 9', 10, 17a, 17b), which is configured to rotate the first wheel (3a) around the first steering axis (6a) and the second wheel (3b) around the second steering axis (6b); - the second steering axis (6b) is different from and parallel to the first steering axis (6a), the first steering axis (6a) is perpendicular to the first wheel axis (4a), and the second steering axis (6b) is perpendicular to the second wheel axis (4b); - the first wheel (3a) and the second wheel (3b) are coupled to each other by the steering drive system (9, 9', 10, 17a, 17b) to enforce that the first wheel axis (4a) and the second wheel axis (4b) are parallel to each other.
  2. Omnidirectional wheel arrangement (1) according to claim 1, wherein - the propulsion drive system (7a, 7b, 19, 20, 21, 22) comprises a first motor (7a) arranged and configured to drive the first wheel (3a) and a second motor (7b) arranged and configured to drive the second wheel (3b); and/or - the steering drive system (9, 9', 10, 17a, 17b) comprises at least one further motor (9, 9') arranged and configured to drive the first wheel (3a) and the second wheel (3b) to rotate around the first steering axis (6a) and the second steering axis (6b), respectively.
  3. Omnidirectional wheel arrangement (1) according to one of the preceding claims, wherein the first steering axis (6a) intersects the first wheel axis (4a) and/or the second steering axis (6b) intersects the second wheel axis (4b).
  4. Omnidirectional wheel arrangement (1) according to one of the preceding claims, wherein the steering drive system (9, 9', 10, 17a, 17b) is configured to rotate the first wheel (3a) and the second wheel (3b) individually around the first steering axis (6a) and the second steering axis (6b), respectively, such that it is enforced that the first wheel axis (4a) and the second wheel axis (4b) are parallel to each other.
  5. Omnidirectional wheel arrangement (1) according to one of the preceding claims, wherein the steering drive system (9, 9', 10, 17a, 17b) comprises a mechanical coupling element (10), which couples the first wheel (3a) and the second wheel (3b) to each other to enforce that the first wheel axis (4a) and the second wheel axis (4b) are parallel to each other.
  6. Omnidirectional wheel arrangement (1) according to claim 5, wherein the mechanical coupling element (10) comprises a transmission belt or a transmission chain or a gearbox or a Cardan shaft.
  7. Omnidirectional wheel arrangement (1) according to one of claims 5 or 6, wherein - the omnidirectional wheel arrangement (1) comprises a first roller or gear (17a) mounted to the carrier (2) such that the first roller or gear (17a) is rotatable around the first steering axis (6a) and the first roller or gear (17a) is mechanically coupled to the first wheel (3a) such that a rotation of the first roller or gear (17a) around the first steering axis (6a) causes the first wheel (3a) to rotate around the first steering axis (6a); - the omnidirectional wheel arrangement (1) comprises a second roller or gear (17b) mounted to the carrier (2) such that the second roller or gear (17b) is rotatable around the second steering axis (6b) and the second roller or gear (17b) is mechanically coupled to the second wheel (3b) such that a rotation of the second roller or gear (17b) around the second steering axis (6b) causes the second wheel (3b) to rotate around the second steering axis (6b); - the mechanical coupling element (10) comprises the transmission belt or the transmission chain, which couples the first roller or gear (17a) and the second roller or gear (17b) to each other to enforce that the first wheel axis (4a) and the second wheel axis (4b) are parallel to each other; and - the steering drive system (9, 9', 10, 17a, 17b) is configured to drive the first roller or gear (17a) to rotate around the first steering axis (6a) or to drive the second roller or gear (17b) to rotate around the second steering axis (6b) or to drive the mechanical coupling element (10).
  8. Omnidirectional wheel arrangement (1) according to one of the preceding claims, wherein the first wheel (3a) is mounted floatingly or spring-mounted at the carrier (2) and/or the second wheel (3b) is mounted floatingly or spring-mounted at the carrier (2).
  9. Omnidirectional wheel arrangement (1) according to one of the preceding claims comprising at least one support element (14a, 14b, 15a, 15b, 15c, 15d) for supporting the omnidirectional wheel arrangement (1) on a ground surface (13).
  10. Omnidirectional wheel arrangement (1) according to one of the preceding claims comprising at least one further wheel (15a, 15b, 15c, 15d) mounted to the carrier (2), wherein each further wheel (15a, 15b, 15c, 15d) is a passive wheel and is rotatable around a respective further steering axis, which is parallel to the first steering axis (6a).
  11. Omnidirectional wheel arrangement (1) according to claim 10, wherein the at least one further wheel (15a, 15b, 15c, 15d) comprises three or four further wheels (15a, 15b, 15c, 15d).
  12. Omnidirectional wheel arrangement (1) according to claim 11, wherein - the three or four further wheels (15a, 15b, 15c, 15d) are arranged at respective corners of a rectangle; and - the first wheel (3a) and the second wheel (3b) are arranged symmetrically with respect to a center of the rectangle.
  13. Vehicular device (11) comprising an omnidirectional wheel arrangement (1) according to one of the preceding claims, wherein the carrier (2) is mounted to the vehicular device (11).
  14. Vehicular device (11) according to claim 13, which is a mobile medical device or a hospital bed or a mobile medical imaging device (12) or a patient table or a robotic system for medical interventions.
  15. Vehicular device (11) according to one of claims 13 or 14, wherein - the omnidirectional wheel arrangement (1) is implemented according to one of claims 10 to 12; - the first wheel (3a) and the second wheel (3b) and the at least one further wheel is mounted at the carrier (2) such that, when the vehicular device (11) is placed on a ground surface (13) such that the first wheel (3a) and the second wheel (3b) and the at least one further wheel are in contact with the ground surface (13), a mechanical load on the first wheel (3a) due to a weight of the vehicular device (11) is less than a mechanical load on each further wheel and/or a mechanical load on the second wheel (3b) due to the weight of the vehicular device (11) is less than the mechanical load on each further wheel.

Description

The present invention is directed to an omnidirectional wheel arrangement for a vehicular device comprising a carrier for mounting the omnidirectional wheel arrangement to the vehicular device, a first wheel with a first wheel axis, and a second wheel with a second wheel axis. The invention is further directed to a vehicular device comprising said omnidirectional wheel arrangement. In the modern clinical setting, autonomous or semi-autonomous mobile medical devices, such as hospital beds, patient tables or mobile medical imaging devices, become more and more common. Such devices may for example be equipped with an omnidirectional drive system, for example based on so-called Mecanum wheels, also denoted as lion wheels. Ilon wheels may be driven by respective motors to allow the device to travel along arbitrary directions autonomously or semi-autonomously. Due to the asymmetric construction of the lion wheel, four individually driven wheels are required to achieve a resulting frictional force along any direction to enable the omnidirectional translational movement and a net torque to allow for a rotational movement. Consequently, four motors are required. Furthermore, the design of an lion wheel is comparatively complex since it comprises a plurality of individual rolls arranged along the circumference of the wheel, which makes the wheel prone to soiling, which could reduce the reliability or smoothness of the motion. It is an objective of the present invention to provide an improved concept for an omnidirectional wheel arrangement for a vehicular device, which overcomes the drawbacks of Ilon wheels at least in part. This objective is achieved by the subject matter of the independent claim. Further implementations and preferred embodiments are subject matter of the dependent claims. The invention is based on the idea to provide two actively driven wheels, each wheel being able to rotate not only around its respective wheel axis but also around a steering axis, which is perpendicular to the wheel axis, and to couple the two wheels to each other to enforce that the wheel axes are parallel to each other. According to an aspect of the invention, a wheel arrangement for a vehicular device, in particular an omnidirectional wheel arrangement for a vehicular device, is provided. The omnidirectional wheel arrangement comprises a carrier for mounting the omnidirectional wheel arrangement to the vehicular device, a first wheel with a first wheel axis, a second wheel with a second wheel axis, and a propulsion drive system. The propulsion drive system is configured to drive the first wheel and the second wheel individually to rotate the first wheel around the first wheel axis and the second wheel around the second wheel axis. The first wheel is mounted to the carrier such that the first wheel is rotatable around a first steering axis, the second wheel is mounted to the carrier such that the second wheel is rotatable around a second steering axis, and the omnidirectional wheel arrangement comprises a steering drive system. The steering drive system is configured to rotate the first wheel around the first steering axis and the second wheel around the second steering axis. Therein, the second steering axis is different from the first steering axis and parallel to the first steering axis, the first steering axis is perpendicular to the first wheel axis, and the second steering axis is perpendicular to the second wheel axis. The first wheel and the second wheel are coupled to each other by the steering drive system to enforce that the first wheel axis and the second wheel axis are parallel to each other. In other words, the steering drive system is designed and configured to enforce that the first wheel axis and the second wheel axis are parallel to each other by coupling the first wheel and the second wheel to each other. In yet other words, the steering drive system is designed and configured to enforce that a rotational position of the first wheel around the first steering axis is equal to a rotational position of the second wheel around the second steering axis, for example up to multiples of 180°. Here and in the following, the expressions perpendicular and parallel may be understood to include usual tolerances, for example in the order of one degree or few degrees, for example [0°, 10°]. Here and in the following, a vehicular device may be understood as a device with a self-propulsion. An omnidirectional wheel arrangement for a vehicular device may be understood as a wheel arrangement which implements the self-propulsion at least in part and, when mounted accordingly to the vehicular device, enables the vehicular device to carry out a translational movement along arbitrary directions and a rotation of the vehicle or device. The rotation of the vehicular device is not necessarily a rotation on the spot. A wheel axis may be understood as an axis of rotation of the respective wheel wherein, if the wheel has contact to a gro