EARLIEST PRIORITY DATE:

This Application claims priority from a Complete patent application filed in India having Patent Application No. 202121008590, filed on March 01, 2021 and titled “A BOGIE SUSPENSION SYSTEM FOR AN UNMANNED GROUND VEHICLE”.

FIELD OF INVENTION

Embodiments of a present invention relate to an unmanned vehicle, and more particularly, to a bogie suspension system for an unmanned ground vehicle (UGV).

BACKGROUND An unmanned ground vehicle (UGV) is a vehicle that operates while in contact with the ground and without an onboard human presence. UGVs have a broad range of applications mostly in areas where a human presence is dangerous or not possible. The UGVs generally includes a set of sensors to observe the environment, and will either autonomously make decisions about its behavior or pass the information to a human operator at a different location who will control the vehicle through wireless communication. In such conventional UGVs, there is no provision for wheel travel with respect to a chassis of the UGV, wherein the wheels are rigidly mounted and can only rotate. Due to such limitation, the impact and shocks which gets generated are transmitted to the other parts of the UGV. This causes uneven traction at the wheels, thereby such UGV designs hamper the directional stability, which in turn reduces the life of the components and makes the ride of the UGV uncomfortable. In addition, tire wear and jerk level is high in such designs, due to which high maintenance is required, which makes such UGVs expensive. Furthermore, springs and dampers are provided to absorb the shocks and to the unevenness of the landscape. This design provides limited wheel travel and is prone to bottoming out, if the UGV is overloaded or if it is travelling in over -rugged terrains. In addition, the conventional design of the UGVs includes many components and hence are more prone to wear and tear, and maintenance. Such limitations increases un-sprung weight and reduces ride comfort. In order to minimize the rolling of UGV during cornering, Sway bars or Anti roll bars are provided, which in turn increases weight of the UGVs and also makes it expensive.

Hence, there is a need for an improved bogie suspension system for an unmanned ground vehicle to address the aforementioned issues.

BRIEF DESCRIPTION

In accordance with one embodiment of the disclosure, a bogie suspension system for an unmanned ground vehicle is provided. The system includes at least four bogie axles, wherein at least two of the at least four bogie axles are parallelly coupled to each longitudinal side of a chassis of the unmanned ground vehicle. Each of the at least four bogie axles include a bogie beam including at least two wheel hubs. Each of the at least four bogie axles also include a supporting tube operatively coupled along a pivot axis. Each of the at least four bogie axles also include a propeller shaft housed within the supporting tube configured to provide propulsion and tractive effort for the unmanned ground vehicle. The system also includes an obstacle detection unit operatively coupled the corresponding at least four bogie axles. The obstacle detection unit includes a front set of sensors housed at a front end of the unmanned ground vehicle. The obstacle detection unit includes a rear set of sensors housed at a rear end of the unmanned ground vehicle. The front set of sensors and the rear set of sensors are configured to detect one or more obstacles present on the front end and the rear end of the unmanned ground vehicle respectively, while travelling on the terrain. The system also includes a suspension control unit operatively coupled to the obstacle detection unit. The suspension control unit includes a swivel motor operatively coupled to the corresponding bogie beam. The swivel motor is configured to rotate the bogie beam to nullify an uneven effect of the terrain while the unmanned ground vehicle is travelling on the terrain. The obstacle detection unit also includes a rotary encoder operatively coupled to the corresponding bogie beam. The rotary encoder is configured to determine a position of the bogie beam to calculate an amount of rotation of the corresponding bogie beam to operate the bogie suspension system on the terrain. To further clarify the advantages and features of the present disclosure, a more particular description of the disclosure will follow by reference to specific embodiments thereof, which are illustrated in the appended figures. It is to be appreciated that these figures depict only typical embodiments of the disclosure and are therefore not to be considered limiting in scope. The disclosure will be described and explained with additional specificity and detail with the appended figures.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure will be described and explained with additional specificity and detail with the accompanying figures in which: FIG. 1 is a schematic representation of a top view of a bogie suspension system for an unmanned ground vehicle (UGV) in accordance with an embodiment of the present disclosure;

FIG. 2 is a schematic representation of a top view of an embodiment of the bogie suspension system for an unmanned ground vehicle (UGV) of FIG. 1 in accordance with an embodiment of the present disclosure;

FIG. 3 is a schematic representation of a top view of a bogie axle of the UGV of FIG. 1 in accordance with an embodiment of the present disclosure;

FIG. 4 is a schematic representation of a side view of a plurality of wheels of the UGV while travelling on an even terrain of FIG. 1 in accordance with an embodiment of the present disclosure; and

FIG. 5 is a schematic representation of a side view of a plurality of wheels of the UGV while travelling on an uneven terrain of FIG. 1 in accordance with an embodiment of the present disclosure.

Further, those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and may not have necessarily been drawn to scale. Furthermore, in terms of the construction of the device, one or more components of the device may have been represented in the figures by conventional symbols, and the figures may show only those specific details that are pertinent to understanding the embodiments of the present disclosure so as not to obscure the figures with details that will be readily apparent to those skilled in the art having the benefit of the description herein.

DETAILED DESCRIPTION For the purpose of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiment illustrated in the figures and specific language will be used to describe them. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended. Such alterations and further modifications in the illustrated system, and such further applications of the principles of the disclosure as would normally occur to those skilled in the art are to be construed as being within the scope of the present disclosure.

The terms "comprises", "comprising", or any other variations thereof, are intended to cover a non-exclusive inclusion, such that a process or method that comprises a list of steps does not include only those steps but may include other steps not expressly listed or inherent to such a process or method. Similarly, one or more devices or sub-systems or elements or structures or components preceded by "comprises... a" does not, without more constraints, preclude the existence of other devices, sub-systems, elements, structures, components, additional devices, additional sub-systems, additional elements, additional structures or additional components. Appearances of the phrase "in an embodiment", "in another embodiment" and similar language throughout this specification may, but not necessarily do, all refer to the same embodiment.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure belongs. The system, methods, and examples provided herein are only illustrative and not intended to be limiting.

In the following specification and the claims, reference will be made to a number of terms, which shall be defined to have the following meanings. The singular forms “a”, “an”, and “the” include plural references unless the context clearly dictates otherwise. Embodiments of the present disclosure relate to a bogie suspension system for an unmanned ground vehicle (UGV). As used herein, the term ‘UGV’ is defined as type of a vehicle that operates while in contact with the ground and without an onboard human presence. Also, the term ‘bogie’ is defined as is a chassis or framework that carries a wheelset, attached to a vehicle or a subassembly of wheels and axles. Further, the term

‘suspension system’ is defined as a system comprising multiple components which are connected between a vehicle and a set of wheels which allows a relation motion between the same.

Turning to FIGs 1, 2 and 3, FIG. 1 is a schematic representation of a top view of a bogie suspension system (10) for an unmanned ground vehicle (UGV) (20) in accordance with an embodiment of the present disclosure. FIG. 2 is a schematic representation of a top view of an embodiment of the bogie suspension system (10) for an unmanned ground vehicle (UGV) (20) of FIG. 1 in accordance with an embodiment of the present disclosure. FIG. 3 is a schematic representation of a top view of a bogie axle (30) of the UGV (20) of FIG. 1 in accordance with an embodiment of the present disclosure.

The system (10) includes at least four bogie axles (30) (as shown in FIG. 3). At least two of the at least four bogie axles (30) are parallelly coupled to each longitudinal side of a chassis of the unmanned ground vehicle (20). More specifically, each side of the UGV (20) includes two bogie axles each (30). In one embodiment, the at least four bogie axles (30) may be one of a non-floating type, a semi-floating type or a full floating type. In another embodiment, the at least four bogie axles (30) may be one of a normal (straight) axle or a portal (offset) axle. More specifically, Wheels hubs (50) are inline or offset with respect to the pivot axis (80).

Further, each of the at least four bogie axles (30) include a bogie beam (40). The bogie beam (40) includes at least two wheel hubs (50). Each of the bogie beam (40) is configured to hold a wheel (60) each via the corresponding at least two wheel hubs (50). More specifically, each of the at least two wheel hubs (50) are mechanically coupled with a wheel (60). In light of the above, in one embodiment, each side of the UGV (20) may include at least four wheels (60), wherein two of the at least four wheels (60) may be coupled to a first axle of the at least four bogie axle (30) and another two of the at least four wheels (60) may be coupled to a second axle of the at least four bogie axles (30). In one specific embodiment, the bogie beam (40) may correspond to a rectilinear cross-sectional tubular structure. In one exemplary embodiment, the wheel (60) may be an aired tired. In another exemplary embodiment, the wheel (60) may be composed of any of a Resilient Material. In one specific embodiment, the wheel (60) may be enclosed in track composed of either a metal, a rubber, or the like; a chain or the like to increase traction.

Each of the at least four bogie axles (30) also include a supporting tube (70) operatively coupled along a pivot axis (80). The supporting tube (70) is configured to support the bogie beam (30). In one embodiment, the supporting tube (70) may correspond to a hollow cylindrical tube. Furthermore, the of the at least four bogie axles (30) also include a propeller shaft (90) housed within the supporting tube (70). The propeller shaft (90) is driven by a prime mover, wherein the propeller shaft (90) is configured to provide propulsion and tractive effort for the unmanned ground vehicle (20). As used herein, the term ‘propulsion’ is defined as an action or a process of pushing or pulling an object in order to drive the same in a forward or a backward direction. Also, the term ‘tractive effort’ is defined as total traction that a vehicle exerts on a surface, where traction is a type of used force used to generate motion between a body and a tangential surface. In one exemplary embodiment, the propeller shaft (90) may be one of a hollow or a solid cylindrical tube. Each of the at least four bogie axles (30) rotate according to one or more unevenness while travelling on a terrain. The term ‘terrain’ is defined as a stretch of land, especially with regard to its physical features. In such embodiment, the terrain may be an uneven surface or a even surface. Further, in one exemplary embodiment, the each of the at least four bogie axles (30) are configured to independently rotate along the pivotal axis (80). In such embodiment, each of the at least four bogie axles (30) operate in either forward direction or in a reverse direction.

In one specific embodiment, the prime mover may be one of an IC engine, an electric motor, a jet engine, or the like which may be configured to Propulsion and Tractive effort. Furthermore, transmission of the UGV may include one of a shaft drive, a chain drive, gear drive, a fluid drive or a combination thereof. The system (10) also includes an obstacle detection unit (100) operatively coupled the corresponding at least four bogie axles (30). The obstacle detection unit (100) includes a front set of sensors (110) housed at a front end of the unmanned ground vehicle (20). In one embodiment, the front set of sensors (110) may include one of a LiDAR, a RADAR, a Sonar, or the like.

The obstacle detection unit (100) also includes a rear set of sensors (120) housed at a rear end of the unmanned ground vehicle (20). In one embodiment, In one embodiment, the rear set of sensors (110) may include one of a LiDAR, a RADAR, a Sonar, or the like. The front set of sensors (110) and the rear set of sensors (120) are configured to detect one or more obstacles present on the front end and the rear end of the unmanned ground vehicle (20) respectively, while travelling on the terrain. In one embodiment, the obstacles may include a hump, a rock or the like.

Furthermore, the system (10) includes a suspension control unit (130) operatively coupled to the obstacle detection unit (100). The suspension control unit (130) includes a swivel motor (140) operatively coupled to the corresponding bogie beam (40) of the corresponding at least four bogie axles (30). The swivel motor (140) is configured to rotate the bogie beam (40) to nullify an uneven effect of the terrain while the unmanned ground vehicle (20) is travelling on the terrain (170) (as shown in FIG. 5). In one embodiment, the swivel motor (140) may be a rotary actuator. In a specific embodiment, the UGV may travel smoothly on an even terrain (160) (as shown in FIG. 4). In one exemplary embodiment, the bogie beam (40) may be rotated to more than 360 degrees.

The suspension control unit (130) also includes a rotary encoder (150) operatively coupled to the corresponding bogie beam (40). The suspension control unit (130) is configured to determine a position of the bogie beam (40) to calculate an amount of rotation of the corresponding bogie beam (40) to operate the bogie suspension system (10) on the terrain. In one embodiment, the swivel motor (140) may include one of an electric motor, a hydraulic motor, a rotary actuator, or a combination thereof. Referring back to the above mentioned embodiment, the swivel motor (140) may be configured to operate in about 360 degrees in either the forward direction or in the reverse direction. In such embodiment, the swivel motor (140) may be switched ON and OFF at any time during operation of the UGV (20) on the terrain. In such embodiment, when the swivel motor (140) may be turned OFF, Bogie Balancing is required to operate the UGV (20). In one exemplary embodiment, if the swivel motor (140) may be switched OFF, Bogie Balancing is required. Further, dedicated Bogie Balancing Mechanism may be coupled to achieve the bogie balancing; also, when reversible mechanism is used to transmit power from Swivel Motor to Bogie Beam

In one exemplary embodiment, the system (10) may further include a Skid-steer operatively coupled to the corresponding at least four bogie axles (30). The Skid-steer is configured to manage direction of operation of the unmanned ground vehicle (20) while traveling on the terrain.

In one specific embodiment, the system (10) may further include at least one hub motor operatively coupled to the corresponding bogie beam (40). The at least one hub motor may be configured to provide torque to the corresponding wheel (60) of the is motor is configured to provide torque to the corresponding wheel (60) of the corresponding bogie beam (40). In one exemplary embodiment, the at least one hub motor may include one of an electric motor, a hydraulic motor or a combination thereof.

Furthermore, in a specific embodiment, the UGV (20) may be controlled by applying one or more brakes. In such embodiment, the one or more brakes may be employed on each of the at least two wheel hubs (50). In such another embodiment, the one or more brakes may be employed unitarily for each of the at least four bogie axles (30). In another specific embodiment, rotary union may also be used for fluid transmission through the joint. In some embodiments, at least one slip rings may also be used to transmit electric current/signals through the joint. In operation, the front set of sensors (110) and the rear set of sensors (120) are employed into the UGV (20) for scanning, detection and ranging of surroundings of the terrain. Inputs from the corresponding front set of sensors (110) and the rear set of sensors (120) is processed using a processing device and virtual terrain map is created. The virtual map is further used to determine obstacles and disturbances in the terrain. Upon detecting the one or more obstacles, a signal to actuate the swivel motor (140) to overcome the disturbance or to nullify its effect on the UGV (20) due to the presence of the one or more obstacles. Depending on intensity of obstruction by the one or more obstacles, the swivel motor (140) rotates in corresponding direction at a required angle. The rotation of the swivel motor (140) makes the bogie beam (40) to rotate and thus nullifying the effect of uneven terrain. Further, the rotary encoder is used to determine the position of the Bogie Beam (40) and the amount of rotation done.

Various embodiments of the present disclosure enable the bogie suspension system to eliminate the need of Springs and Dampers to absorb the impact and unevenness provided by the terrain to the UGVs. the Bogie Axle Travel is always parallel to the longitudinal axis of the UGV, there is no body roll and this eliminates the need of sway bar or anti-roll bar. In addition, as the Bogie Axle Travel is always parallel to the longitudinal axis of UGV, there is no change in the camber of the wheels, hence no need of camber control units. Furthermore, as the system does not include springs and dampers, the anti-dive and anti-squat characteristics entirely depend on the properties of the wheels and tires.

Also, since each of the bogie axle is independent of each other, can rotate as per the unevenness of the terrain which in turn provides maximum comfort and stable ride, thereby making the system more reliable and efficient for its application. In addition, maximum possible wheel travel can be achieved by the system as bogie axles are entirely outside of the body of the UGV, this design does not limit the amount of wheel travel on the terrain. Further, the system is configured to achieve maximum traction as the amount of wheel travel is entirely dictated by the unevenness of the terrain. Further, the cross-country mobility is improved as the tractive effort is provided to all the wheels.

Moreover, the system comprises of lesser number of components. This reduces wear and tear of the components of the UGV, which in-turn reduces maintenance cost and weight of the UGV, thereby making the system less expensive as compared to the conventional UGVs. In addition, the mechanism used to transmit power from Swivel Motor to the Bogie Beam can be of Reversible or Non-reversible type. Each Bogie Beam has its own brake to maintain its position with respect to the Chassis. While specific language has been used to describe the disclosure, any limitations arising on account of the same are not intended. As would be apparent to a person skilled in the art, various working modifications may be made to the method in order to implement the inventive concept as taught herein. The figures and the foregoing description give examples of embodiments. Those skilled in the art will appreciate that one or more of the described elements may well be combined into a single functional element. Alternatively, certain elements may be split into multiple functional elements. Elements from one embodiment may be added to another embodiment. For example, order of processes described herein may be changed and are not limited to the manner described herein. Moreover, the actions of any flow diagram need not be implemented in the order shown; nor do all of the acts need to be necessarily performed. Also, those acts that are not dependent on other acts may be performed in parallel with the other acts. The scope of embodiments is by no means limited by these specific examples.