Patent Publication Number: US-2021171104-A1

Title: Adaptive chassis and robot

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is based upon and claims priority to Chinese patent application No. 201810191643.7 filed on Mar. 8, 2018, the disclosure of which is hereby incorporated by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to the technology of chassis, and in particular to an adaptive chassis and a robot. 
     BACKGROUND 
     A chassis is an important part of a vehicle, and the vehicle moves on a supporting surface through wheels on the chassis. Common vehicles are provided with multiple wheels, so that the vehicles and objects carried by the vehicles may be supported by the multiple wheels, thus the pressure on each wheel may be reduced. The chassis in the prior art is typically provided with four wheels, and the chassis is supported by the four wheels. However, if the chassis is rigidly supported by four wheels, an over-positioning phenomenon will occur, which causes one of the four wheels to get out of contact with the supporting surface. If the wheel gets out of contact with or in virtual contact with the supporting surface is a driving wheel, the vehicle is prone to control overshoot, which affects the running stability of the vehicle, and even affects the security. 
     SUMMARY 
     To solve the above technical problems, embodiments of the present disclosure provide an adaptive chassis and a robot. 
     The technical solutions of the embodiments of the present disclosure are as follows. 
     The embodiments of the present disclosure provide a chassis. The chassis includes: a support, a first wheel and a second wheel arranged at two sides of a first end of the support, a first suspension seat arranged at the bottom side of the second end of the support, a first rotating shaft arranged on the first suspension seat, a first crossbeam connected with the first rotating shaft and being capable of rotating around the first rotating shaft, and a third wheel and a fourth wheel arranged on two ends of the first crossbeam. 
     An axis of the first rotating shaft is consistent with a moving direction of the chassis. 
     When a state of a supporting surface changes and one of the third wheel and the fourth wheel gets out of contact with the supporting surface, the out-of-contact one of the third wheel and the fourth wheel can rotate around the first rotating shaft by means of the first crossbeam to make contact with the supporting surface. 
     In some optional implementation modes, the chassis further includes a first plate spring. A middle of the plate spring is fixed on the first suspension seat. The two sides of the first crossbeam with respect to the first suspension seat are respectively provided with a first position limiting seat and a second position limiting seat. The first position limiting seat is provided with a first through groove mating with a first end of the first plate spring, and the second position limiting seat is provided with a second through groove mating with a second end of the first plate spring. 
     The first end of the first plate spring is inserted in the first through groove and is capable of sliding in the first through groove. The second end of the first plate spring is inserted in the second through groove and is capable of sliding in the second through groove. 
     In some optional implementation modes, the first wheel and the second wheel are driving wheels, and the third wheel and the fourth wheel are driven wheels; or 
     the third wheel and the fourth wheel are the driving wheels, and the first wheel and the second wheel are the driven wheels; or 
     all of the first wheel, the second wheel, the third wheel and the fourth wheel are the driving wheels. 
     In some optional implementation modes, each driven wheel is a universal wheel, and a middle of each driving wheel is provided with a wheel hub motor. 
     In some optional implementation modes, a connecting seat is arranged at a top side of the support, a connecting shaft being arranged on the connecting seat, and an axis of the connecting shaft being vertical to the axis of the first rotating shaft. 
     The chassis further includes a supporting bracket. There is a wheel set arranged on a rear end of the supporting bracket, and a middle of the supporting bracket is connected with the connecting shaft and is capable of rotating around the connecting shaft. 
     When the support pulls, by means of the connecting shaft, the supporting bracket to move over the supporting surface, the wheel set rotates around the connecting shaft by means of the supporting bracket to make contact with the supporting surface. 
     In some optional implementation modes, the connecting seat includes a first connecting seat and a second connecting seat arranged at opposite sides of the top side of the support. The connecting shaft includes a first connecting shaft arranged on the first connecting seat and a second connecting shaft arranged on the second connecting seat. The axis of the first connecting shaft is vertical to an axis of the first rotating shaft; and an axis of the first connecting shaft is collinear with an axis of the second connecting shaft. 
     Two sides of the middle of the supporting bracket are respectively provided with a first connecting hole mating with the first connecting shaft and a second connecting hole mating with the second connecting shaft. The first connecting shaft is arranged in the first connecting hole, and the first connecting shaft is in clearance fit with the first connecting hole. The second connecting shaft is arranged in the second connecting hole, and the second connecting shaft is in clearance fit with the second connecting hole. 
     When the support pulls, by means of the first connecting shaft and the second connecting shaft, the supporting bracket to move over the supporting surface, the wheel set rotates around the first connecting shaft and the second connecting shaft by means of the supporting bracket to make contact with the supporting surface. 
     In some optional implementation modes, the chassis further includes a second plate spring and a third plate spring. 
     A middle of the second plate spring is fixed on the first connecting seat. Two sides of the supporting bracket with respect to the first connecting seat are respectively provided with a third position limiting seat and a fourth position limiting seat. The third position limiting seat is provided with a third through groove mating with a first end of the second plate spring, and the fourth position limiting seat is provided with a fourth through groove mating with a second end of the second plate spring. The first end of the second plate spring is inserted in the third through groove and is capable of sliding in the third through groove, and the second end of the second plate spring is inserted in the fourth through groove and is capable of sliding in the fourth through groove. 
     A middle of the third plate spring is fixed on the second connecting seat. Two sides of the supporting bracket with respect to the second connecting seat are respectively provided with a fifth position limiting seat and a sixth position limiting seat. The fifth position limiting seat is provided with a fifth through groove mating with a first end of the third plate spring, and the sixth position limiting seat is provided with a sixth through groove mating with a second end of the third plate spring. The first end of the third plate spring is inserted in the fifth through groove and is capable of sliding in the fifth through groove, and the second end of the third plate spring is inserted in the sixth through groove and is capable of sliding in the sixth through groove. 
     In some optional implementation modes, the first connecting seat and the second connecting seat are respectively at opposite sides of a top side of the second end of the support, a front end of the supporting bracket is correspondingly at a top side of the first end of the support, and the third wheel and the fourth wheel are arranged at the middle of the supporting bracket; or, 
     the first connecting seat and the second connecting seat are respectively at the opposite sides of the top side of the first end of the support, the front end of the supporting bracket is correspondingly at the top side of the second end of the support, and the first wheel and the second wheel are arranged at the middle of the supporting bracket. 
     In some optional implementation modes, the wheel set includes a fifth wheel and a sixth wheel. The third wheel and the fourth wheel arranged at the middle of the supporting bracket are the driving wheels, and the first wheel, the second wheel, the fifth wheel and the sixth wheel are the driven wheels. Distances from a center between the third wheel and the fourth wheel to the first wheel, the second wheel, the fifth wheel and the sixth wheel are equal, and the center between the third wheel and the fourth wheel is at an intersection of two diagonals formed by the first wheel, the second wheel, the fifth wheel and the sixth wheel; or 
     the first wheel and the second wheel arranged at the middle of the supporting bracket are the driving wheels, and the third wheel, the fourth wheel, the fifth wheel and the sixth wheel are the driven wheels; distances from a center between the first wheel and the second wheel to the third wheel, the fourth wheel, the fifth wheel and the sixth wheel are equal, and the center between the first wheel and the second wheel is at an intersection of two diagonals formed by the third wheel, the fourth wheel, the fifth wheel and the sixth wheel. 
     In some optional implementation modes, the chassis further includes a second suspension seat arranged at a bottom side of the rear end of the supporting bracket, a second rotating shaft arranged on the second suspension seat, and a second crossbeam connected with the second rotating shaft and being capable of rotating around the second rotating shaft; the wheel set includes a fifth wheel and a sixth wheel arranged on two ends of the second crossbeam. 
     An axis of the second rotating shaft is consistent with the moving direction of the chassis. 
     When the support pulls, by means of the connecting shaft, the supporting bracket to move over the supporting surface, and when the state of the supporting surface changes and one of the fifth wheel and the sixth wheel gets out of contact with the supporting surface, the out-of-contact one of the fifth wheel and the sixth wheel can rotate around the second rotating shaft by means of the second crossbeam to make contact with the supporting surface. 
     In some optional implementation modes, the chassis further includes a supporting plate arranged at the bottom side of the rear end of the supporting bracket, and an accommodating space arranged at a top side of the supporting plate. 
     The second suspension seat is arranged at the top side of the supporting plate and in the accommodating space. Positions, corresponding to the fifth wheel and the sixth wheel, of the supporting plate are respectively provided with openings. The fifth wheel and the sixth wheel are at the bottom side of the supporting plate after passing through respective openings; and the second crossbeam can rotate in the accommodating space around the second rotating shaft. 
     In some optional implementation modes, the chassis further includes position limiting slots arranged at the bottom side of the rear end of the supporting bracket and respectively mating with two ends of the second crossbeam. The two ends of the second crossbeam are inserted in respective position limiting slots, and preset clearances are formed between the two ends of the second crossbeam and the respective position limiting slots in a rotating direction of the second crossbeam. 
     When the second crossbeam rotates in the accommodating space around the second rotating shaft, the two ends of the second crossbeam limit a rotation angle of the second crossbeam by means of the position limiting slots. 
     The embodiments of the present disclosure also provide a robot. The robot includes the adaptive chassis recorded in the embodiments of the present disclosure. 
     In the embodiments of the present disclosure, when the state of the supporting surface changes and one of the third wheel and the fourth wheel gets out of contact with the supporting surface, the out-of-contact one of the third wheel and the fourth wheel can rotate around the first rotating shaft by means of the first crossbeam to make contact with the supporting surface. The embodiments solve the problem of over-positioning phenomenon occurring between the chassis rigidly supported by four wheels and the supporting surface, so that the four wheels can contact with the supporting surface in the moving process, thus the running stability and security of the vehicle in moving is improved. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a schematic diagram of an optional structure of a chassis according to an embodiment of the present disclosure. 
         FIG. 2  illustrates a schematic diagram of another optional structure of a chassis according to an embodiment of the present disclosure. 
         FIG. 3  illustrates a partial diagram of another optional structure of a chassis according to an embodiment of the present disclosure. 
         FIG. 4  illustrates a schematic diagram of an optional structure of a fifth position limiting seat in a chassis according to an embodiment of the present disclosure. 
         FIG. 5  illustrates a schematic diagram of another optional structure of a chassis according to an embodiment of the present disclosure. 
         FIG. 6  illustrates a schematic diagram of an optional structure of a supporting bracket in a chassis according to an embodiment of the present disclosure. 
         FIG. 7  illustrates a schematic diagram of another optional structure of a chassis according to an embodiment of the present disclosure. 
         FIG. 8  illustrates a partial view of another optional structure of a chassis according to an embodiment of the present disclosure. 
         FIG. 9  illustrates a schematic diagram of another optional structure of a supporting bracket in a chassis according to an embodiment of the present disclosure. 
         FIG. 10  illustrates a schematic diagram of another optional structure of a supporting bracket in a chassis according to an embodiment of the present disclosure. 
         FIG. 11  illustrates a schematic diagram of another optional structure of a supporting bracket in a chassis according to an embodiment of the present disclosure. 
     
    
    
     Reference numbers in the accompanying drawings are as follows:  110  support;  101  first wheel;  102  second wheel;  103  third wheel;  104  fourth wheel;  120  first suspension seat;  121  first rotating shaft;  130  first crossbeam;  140  first plate spring;  141  first position limiting seat;  142  second position limiting seat;  143  first through groove;  144  second through groove;  150  supporting bracket;  151  fifth wheel;  152  sixth wheel;  153  clamping hook;  154  second suspension seat;  155  second rotating shaft;  156  second crossbeam;  157  supporting plate;  158  opening;  159  position limiting slot;  160  second connecting seat;  161  second connecting shaft;  170  third plate spring;  171  fifth position limiting seat;  172  sixth position limiting seat;  173  fifth through groove;  174  sixth through groove;  180  first connecting seat; and  181  first connecting shaft. 
     DETAILED DESCRIPTION 
     The present disclosure is further elaborated below in combination with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used for explaining the present disclosure, but not for limiting the present disclosure. 
     In the embodiments of the present disclosure, it is to be noted that unless otherwise definitely specified and limited, the term “connection” should be broadly understood. For example, the term may refer to electrical connection, and may refer to communication in two components. The term may refer to direct connection, may also refer to indirect connection through a medium. For those of ordinary skill in the art, specific meanings of the term can be understood according to a specific condition. 
     It is to be noted that the terms “first/second/third” in the embodiments of the present disclosure are only used for distinguishing similar objects rather than representing a specific sequence of the objects. Understandably, a particular order or sequence of the terms “first/second/third” may be interchanged if permitted. It should be understood that the objects distinguished by “first/second/third” may be exchanged under appropriate circumstances, so that the embodiments of the present disclosure described here may be implemented in an order different from that described or shown herein. 
     The embodiments of the present disclosure provide an adaptive chassis. The chassis in the embodiments of the present disclosure is elaborated below with reference to  FIG. 1  to  FIG. 8 . 
     As illustrated in  FIG. 1  and  FIG. 2 , the chassis provided by the embodiments of the present disclosure includes: a support  110 , a first wheel  101  and a second wheel  102  arranged at two sides of a first end of the support  110 , a first suspension seat  120  arranged at the bottom side of the second end of the support  110 , a first rotating shaft  121  arranged on the first suspension seat  120 , a first crossbeam  130  connected with the first rotating shaft  121  and being capable of rotating around the first rotating shaft  121 , and a third wheel  103  and a fourth wheel  104  arranged on two ends of the first crossbeam  130 . The axis of the first rotating shaft  121  is consistent with the moving direction of the chassis. When the state of a supporting surface changes and one of the third wheel  103  and the fourth wheel  104  gets out of contact with the supporting surface, the out-of-contact one of the third wheel  103  and the fourth wheel  104  can rotate around the first rotating shaft  121  by means of the first crossbeam  130  to make contact with the supporting surface. 
     In the embodiment, as shown in  FIG. 2 , the axis of the first rotating shaft  121  is consistent with the moving direction of the chassis, when the state of the supporting surface changes and one of the third wheel  103  and the fourth wheel  104  gets out of contact with the supporting surface, the out-of-contact one of the third wheel  103  and the fourth wheel  104  can rotate around the first rotating shaft  121  by means of the first crossbeam  130  to make contact with the supporting surface, so the problem of over-positioning of the chassis rigidly supported by four wheels may be solved, and it is ensured that the four wheels of the chassis contact with the supporting surface in the moving process. 
     Those skilled in the art should understand that the first end of the support  110  may be at the front side of the chassis, and may also be at the rear side of the chassis. When the first end of the support  110  is at the front side of the chassis, the second end of the support  110  is at the rear side of the chassis; correspondingly, the first wheel  101  and the second wheel  102  are at the front side of the chassis, and the third wheel  103  and the fourth wheel  104  are at the rear side of the chassis. When the first end of the support  110  is at the rear side of the chassis, the second end of the support  110  is at the front side of the chassis; correspondingly, the first wheel  101  and the second wheel  102  are at the rear side of the chassis, and the third wheel  103  and the fourth wheel  104  are at the front side of the chassis. The direction from the rear side of the chassis to the front side of the chassis is the direction of moving forward of the chassis, and the direction from the front side of the chassis to the rear side of the chassis is the direction of moving backward of the chassis. 
     The first wheel  101  and the second wheel  102  in the embodiment may be the driving wheels, and may also be the driven wheels. When the first wheel  101  and the second wheel  102  are the driving wheels, the third wheel  103  and the fourth wheel  104  are the driven wheels; when the third wheel  103  and the fourth wheel  104  are the driving wheels, the first wheel  101  and the second wheel  102  are the driven wheels. As an example, the driven wheel here may be a universal wheel, and the middle of the driving wheel may be provided with a wheel hub motor, so the chassis may be driven by means of the wheel hub motor provided in the middle of the driving wheel, and the change of the moving direction of the chassis may be flexibly adapted by means of the universal wheel.  FIG. 1  and  FIG. 2  exemplarily illustrate that the first wheel  101  and the second wheel  102  are the universal wheels, and the third wheel  103  and the fourth wheel  104  are the driving wheels. Certainly, all of the first wheel  101 , the second wheel  102 , the third wheel  103  and the fourth wheel  104  may be the driving wheels. 
     In some optional implementation modes of the embodiment, as illustrated in  FIG. 2  and  FIG. 3 , in order to prevent the first crossbeam  130  from rotating too much around the first rotating shaft  121  to affect the smooth moving of the chassis, the chassis further includes a first plate spring  140 , the middle of which is fixed on the first suspension seat  120 . The two sides, relative to the first suspension seat  120 , of the first crossbeam  130  are respectively provided with a first position limiting seat  141  and a second position limiting seat  142 . The first position limiting seat  141  is provided with a first through groove  143  mating with the first end of the first plate spring  140 , and the second position limiting seat  142  is provided with a second through groove  144  mating with the second end of the first plate spring  140 . The first end of the first plate spring  140  is inserted in the first through groove  143  and is capable of sliding in the first through groove  143 . The second end of the first plate spring  140  is inserted in the second through groove  144  and is capable of sliding in the second through groove  144 . 
     Here, the way of fixing the middle of the first plate spring  140  on the first suspension seat  120  is not limited. The middle of the first plate spring  140  may be welded on the first suspension seat  120 , and may also be fixed on the first suspension seat  120  by a screw.  FIG. 3  exemplarily illustrates that the middle of the first plate spring  140  is fixed on the first suspension seat  120  by a screw. The position where the middle of the first plate spring  140  is fixed on the first suspension seat  120  is not limited.  FIG. 3  exemplarily illustrates that the first rotating shaft  121  is arranged at one side of the first suspension seat  120 , and the middle of the first plate spring  140  is fixed on the bottom side of the first suspension seat  120 . 
     Here, the cross-section shape of the first end of the first plate spring  140  may be a triangle, and may also be a trapezoid. The cross-section shape of the second end of the first plate spring  140  and the cross-section shape of the first end of the first plate spring  140  may be the same, and may also be different.  FIG. 3  exemplarily illustrates that the cross-section shape of the first end of the first plate spring  140  and the cross-section shape of the second end of the first plate spring  140  are the same, and are all rectangles. 
     As illustrated in  FIG. 3 , the way of arranging the first position limiting seat  141  at one side of the first crossbeam  130  is not limited. The first position limiting seat  141  is provided with the first through groove  143  mating with the first end of the first plate spring  140 . Here, the cross-section shape of the first through groove  143  may be set according to actual needs, as long as the first end of the first plate spring  140  may be inserted in the first through groove  143 , and may slide in the first through groove  143 . The way of arranging the second position limiting seat  142  at the other side of the first crossbeam  130  is not limited. The second position limiting seat  142  is provided with the second through groove  144  mating with the second end of the first plate spring  140 . Here, the cross-section shape of the second through groove  144  may be set according to actual needs, as long as the second end of the first plate spring  140  may be inserted in the second through groove  144 , and may slide in the second through groove  144 . 
       FIG. 3  exemplarily illustrates that the structure of the first position limiting seat  141  and the structure of the second position limiting seat  142  are the same, and they are fixed on the first crossbeam  130  by a bolt. The cross-section shape of the first end of the first plate spring  140  and the cross-section shape of the first through groove  143  are the same, and are all rectangles. The cross-section shape of the first through groove  143  and the cross-section shape of the second through groove  144  are the same, and are all rectangles. 
     In some optional implementation modes of the embodiment, as illustrated in  FIG. 4  to  FIG. 8 , the top side of the support  110  is provided with a connecting seat on which a connecting shaft is provided. The axis of the connecting shaft is vertical to the axis of the first rotating shaft  121 . The chassis further includes a supporting bracket  150 . The rear side of the supporting bracket  150  is provided with a wheel set. The middle of the supporting bracket  150  is connected with the connecting shaft and is capable of rotating around the connecting shaft. When the support pulls, by means of the connecting shaft, the supporting bracket  150  to move over the supporting surface, the wheel set rotates around the connecting shaft by means of the supporting bracket  150  to make contact with the supporting surface. 
     In the implementation mode, the supporting bracket  150  is used for supporting goods. The goods may be placed on the supporting bracket  150 , and the support  110  pulls the goods on the supporting bracket  150  by means of the connecting shaft. When the state of the supporting surface changes, the wheel set rotates around the connecting shaft by means of the supporting bracket  150  to make contact with the supporting surface, so as to ensure the wheel set of the supporting bracket  150  to provide a stable supporting force for the supporting bracket  150 . The structure and shape of the supporting bracket  150  may be set according to actual needs. As an example, as illustrated in  FIG. 5  to  FIG. 7 , the front end of the supporting bracket  150  is provided with a clamping hook  153 . The first end of the support  110  is clamped at the inner side of the clamping hook  153 , and there is a preset distance between the first end of the support  110  and the clamping hook  153 . When the preset distance satisfies that the supporting bracket  150  rotates around the connecting shaft, the first end of the support  110  does not collide with the clamping hook  153 . 
     In the implementation mode, the axis of the connecting shaft is vertical to the axis of the first rotating shaft  121 , that is, the connecting shaft is vertical to the first rotating shaft  121 . When the chassis is moving, the first crossbeam  130  rotates left and right, and the supporting bracket  150  rotates forward and backward, so as to ensure that the chassis may enable all the wheels to contact with the supporting surface when the state of the supporting surface changes. In this way, not only the adaptability of the chassis to the supporting surface is improved, but also an effective supporting area between the chassis and the supporting surface is increased, thus not only the stability of the whole chassis is improved, but also the loading capacity of the whole chassis is improved. Meanwhile, when the chassis moves from the flat supporting surface to a slope surface, the wheels, at the front side of the chassis, of the support  110  contact with the slope surface first, the wheels, at the rear side of the chassis, of the support  110  will pass through the flat supporting surface and the slope surface successively, and the wheel set of the supporting bracket  150  will also pass through the flat supporting surface and the slope surface successively by means of that the supporting bracket  150  rotates around the connecting shaft, which will not make the wheels, at the rear side of the chassis, of the support  110  get out of contact with the supporting surface, so the problem in the prior art that the middle wheel gets out of contact with the supporting surface when the chassis rigidly supported by multiple wheels climb is solved. Therefore, the chassis has the ability of passing over the slope surfaces and uneven road surfaces. Besides, the supporting bracket  150  and the support  110  are in overlap and staggered joint, the gravity borne by the supporting bracket  150  is distributed over all the wheels, and when the chassis climbs over obstacles, the center of gravity proportionally climbs step by step, thereby reducing a torque requirement on the driving wheel, and improving the overall ability of overcoming obstacles with load of the chassis. 
     The wheel set in the implementation mode may include a wheel, and may also include multiple wheels.  FIG. 5  to  FIG. 7  exemplarily illustrate that the wheel set includes a fifth wheel  151  and a sixth wheel  152 . The fifth wheel  151  and the sixth wheel  152  are arranged at two sides of the rear end of the supporting bracket  150 . The first wheel  101 , the second wheel  102 , the third wheel  103 , the fourth wheel  104 , the fifth wheel  151  and the sixth wheel  152  are evenly distributed in two rows. The wheel set is used for supporting the rear end of the supporting bracket  150 , so that the supporting bracket  150  moves over the supporting surface by means of the wheel set when the support  110  pulls, by means of the connecting shaft, the supporting bracket  150  to move over the supporting surface. When the two sides of the rear end of the supporting bracket  150  are provided with the fifth wheel  151  and the sixth wheel  152 , the fifth wheel  151  and the sixth wheel  152  are simultaneously used for supporting the rear end of the supporting bracket  150 , so it is more reliable for the supporting bracket  150  to move over the supporting surface by means of the fifth wheel  151  and the sixth wheel  152 . It is understandable that the chassis here is provided with six wheels, and the effective supporting area between the chassis and the supporting surface may be increased by means of the six wheels, thereby improving the loading capacity of the whole chassis. 
     In the implementation mode, when the wheel set includes the fifth wheel  151  and the sixth wheel  152 , the fifth wheel  151  and the sixth wheel  152  may be arranged on the rear end of the supporting bracket  150  directly, and may also be arranged on the rear end of the supporting bracket  150  by means of other structures. That the fifth wheel  151  and the sixth wheel  152  are arranged on the rear end of the supporting bracket  150  is exemplarily listed below. 
     For example, the fifth wheel  151  and the sixth wheel  152  are arranged on the rear end of the supporting bracket  150  by means of a second suspension seat. As illustrated in  FIG. 9 , the chassis includes: the second suspension seat  154  arranged at the bottom side of the rear end of the supporting bracket  150 , a second rotating shaft  155  arranged on the second suspension seat  154 , a second crossbeam  156  connected with the second rotating shaft  155  and being capable of rotating around the second rotating shaft  155 , and the fifth wheel  151  and the sixth wheel  152  arranged on two ends of the second crossbeam  156 . The axis of the second rotating shaft  155  is consistent with the moving direction of the chassis. There is a connecting structure arranged between the supporting bracket  150  and the chassis. When the chassis pulls, by means of the connecting structure, the supporting bracket  150  to move over the supporting surface, and the state of the supporting surface changes and one of the fifth wheel  151  and the sixth wheel  152  gets out of contact with the supporting surface, the out-of-contact one of the fifth wheel  151  and the sixth wheel  152  can rotate around the second rotating shaft  155  by means of the second crossbeam  156  to make contact with the supporting surface. 
     In the embodiment, the axis of the second rotating shaft  155  is consistent with the moving direction of the chassis; when the chassis pulls, by means of the connecting structure, the supporting bracket  150  to move over the supporting surface, and the state of the supporting surface changes and one of the fifth wheel  151  and the sixth wheel  152  gets out of contact with the supporting surface, the out-of-contact one of the fifth wheel  151  and the sixth wheel  152  can rotate around the second rotating shaft  155  by means of the second crossbeam  156  to make contact with the supporting surface, so the problem of over-positioning of the supporting bracket  150  rigidly supported by two wheels may be solved, and it is ensured that the two wheels of the supporting bracket  150  contact with the supporting surface in the moving process. 
     In the example, the second suspension seat  154  may be directly arranged on the supporting bracket  150 . Here, the way of arranging the second suspension seat  154  may be the same as the way of arranging the first suspension seat  120  illustrated in  FIG. 2  and  FIG. 3 . The second suspension seat  154  may also be arranged on the supporting bracket  150  by means of other structures. That the second suspension seat  154  is arranged on the supporting bracket  150  by means of a supporting plate  157  is exemplarily listed below. For example, as illustrated in  FIG. 9  to  FIG. 11 , the chassis further includes the supporting plate  157  arranged at the bottom side of the rear end of the supporting bracket  150 , and an accommodating space arranged at the top side of the supporting plate  157 . The second suspension seat  154  is arranged at the top side of the supporting plate  157  and in the accommodating space. The positions, corresponding to the fifth wheel  151  and the sixth wheel  152 , of the supporting plate  157  are respectively provided with openings  158 . The fifth wheel  151  and the sixth wheel  152  are at the bottom side of the supporting plate  157  after passing through respective openings  158 ; and the second crossbeam  156  can rotate in the accommodating space around the second rotating shaft  155 . As an example, as illustrated in  FIG. 10 , in order to prevent the second crossbeam  156  from rotating too much around the second rotating shaft  155  to affect the smooth moving of the supporting bracket  150 , the chassis further includes position limiting slots  159  arranged at the bottom side of the rear end of the supporting bracket  150  and respectively mating with two ends of the second crossbeam  156 . The two ends of the second crossbeam  156  are inserted in respective position limiting slots  159 , and there are preset clearances formed between the two ends of the second crossbeam  156  and the position limiting slots  159  in the rotating direction. When the second crossbeam  156  rotates in the accommodating space around the second rotating shaft  155 , the two ends of the second crossbeam limit a rotation angle of the second crossbeam by means of the position limiting slots  159 . Here, the shape of the position limiting slots  159  may be set according to the shape of the two ends of the second crossbeam  156 , as long as there are preset clearances respectively formed between the two ends of the second crossbeam  156  and the position limiting slots  159  in the rotating direction, so that the two ends of the second crossbeam  156  rotate in the position limiting slots  159 .  FIG. 10  exemplarily illustrates that the cross section of the position limiting slots  159  is a rectangle, and the cross section of the two ends of the second crossbeam  156  is also a rectangle. 
     In the implementation mode, the number of the connecting seats may be one or more than one. When the number of the connecting seats is one, the number of the connecting shafts is also one, and the middle of the supporting bracket  150  rotates around one connecting shaft; when the number of the connecting seats is more than one, each connecting seat is provided with one connecting shaft, and the middle of the supporting bracket  150  rotates around each connecting shaft. It is to be noted that when the number of the connecting seats is more than one, the axes of the connecting shafts of each connecting seat are collinear. 
     For example,  FIG. 5  to  FIG. 7  exemplarily illustrate that the connecting seat includes a first connecting seat  180  and a second connecting seat  160  arranged at opposite sides of the top side of the support  110 . The connecting shaft includes a first connecting shaft  181  arranged on the first connecting seat  180  and a second connecting shaft  161  arranged on the second connecting seat  160 . The axis of the first connecting shaft  181  is vertical to the axis of the first rotating shaft  121 ; and the axis of the first connecting shaft  181  is collinear with the axis of the second connecting shaft  161 . Two sides of the middle of the supporting bracket  150  are respectively provided with a first connecting hole mating with the first connecting shaft  181  and a second connecting hole mating with the second connecting shaft  161 . The first connecting shaft  181  is arranged in the first connecting hole, and the first connecting shaft  181  is in clearance fit with the first connecting hole. The second connecting shaft  161  is arranged in the second connecting hole, and the second connecting shaft  161  is in clearance fit with the second connecting hole. When the support  110  pulls, by means of the first connecting shaft  181  and the second connecting shaft  161 , the supporting bracket  150  to move over the supporting surface, the wheel set rotates around the first connecting shaft  181  and the second connecting shaft  161  by means of the supporting bracket  150  to make contact with the supporting surface. 
     In the example, the specific positions of the first connecting seat  180  and the second connecting seat  160  on the top side of the support  110  are not limited. For example, as illustrated in  FIG. 5  to  FIG. 7 , the first connecting seat  180  and the second connecting seat  160  are respectively at the opposite sides of the top side of the second end of the support  110 , and the front end of the supporting bracket  150  is correspondingly at the top side of the first end of the support, and the third wheel and the fourth wheel are arranged at the middle of the supporting bracket; correspondingly, the wheel set may include the fifth wheel  151  and the sixth wheel  152 , and the fifth wheel  151  and the sixth wheel  152  are arranged at the two sides of the rear end of the supporting bracket. The third wheel  103  and the fourth wheel  104  arranged at the middle of the supporting bracket are the driving wheels, and the first wheel  101 , the second wheel  102 , the fifth wheel  151  and the sixth wheel  152  are the drive wheels. The distances from center between the third wheel  103  and the fourth wheel  104  to the first wheel  101 , the second wheel  102 , the fifth wheel  151  and the sixth wheel  152  are equal, and the center between the third wheel  103  and the fourth wheel  104  is at an intersection of two diagonals formed by the first wheel  101 , the second wheel  102 , the fifth wheel  151  and the sixth wheel  152 . For another example, the first connecting seat  180  and the second connecting seat  160  are respectively at the opposite sides of the top side of the second end of the support  110 , the front end of the supporting bracket is correspondingly at the top side of the second end of the support  110 , and the first wheel  101  and the second wheel  102  are arranged at the middle of the supporting bracket  150 ; correspondingly, the first wheel  101  and the second wheel  102  arranged at the middle of the supporting bracket  150  are the driving wheels, the third wheel  103 , the fourth wheel  104 , the fifth wheel  151  and the sixth wheel  152  are the driven wheels. The distances from center between the first wheel  101  and the second wheel  102  to the third wheel  103 , the fourth wheel  104 , the fifth wheel  151  and the sixth wheel  152  are equal, and the center between the first wheel  101  and the second wheel  102  is at an intersection of two diagonals formed by the third wheel  103 , the fourth wheel  104 , the fifth wheel  151  and the sixth wheel  152 . When the wheel arranged at the middle of the supporting bracket  150  is the driving wheel, the chassis becomes a six-wheel chassis where the driving wheel is arranged at the middle. The advantage of arranging the driving wheel arranged at the middle is that the chassis needs only two driving wheels to achieve pivot steering with a zero turning radius. In the rotating process of the four-wheel chassis illustrated in  FIG. 1 , its turning sweep space of steering sweep is a circle taking the symmetric center of the two driving wheels as the center and taking the distance between the driving wheel and the driven wheel as the radius; here, the turning sweep space of steering sweep of the six-wheel chassis where the driving wheel is arranged at the middle is the same as the turning sweep space of the four-wheel chassis, and the supporting surface of the six-wheel chassis where the driving wheel is arranged at the middle is doubled, so the loading capacity of the chassis is improved to an extreme in the same driving space. Certainly, the distances from the center between the driving wheels arranged at the middle of the supporting bracket  150  to the fifth wheel  151  and the sixth wheel  152  may also be less than the distances from the center between the driving wheels arranged at the middle of the supporting bracket  150  to the driven wheels on the front end of the supporting bracket  150 . The turning sweep space of such a six-wheel chassis where the driving wheel is arranged at the middle is the same as the turning sweep space of the four wheel chassis, and the supporting surface of the six-wheel chassis where the driving wheel is arranged at the middle may also be increased, so the loading capacity of the chassis is improved. 
     In the example, the structure of the first connecting seat  180  and the structure of the second connecting seat  160  may be the same, and may also be different. The structure of the first connecting shaft  181  and the structure of the second connecting shaft  161  here may be the same, and may also be different.  FIG. 5  to  FIG. 7  exemplarily illustrate that the structure of the first connecting seat  180  and the structure of the second connecting seat  160  are the same, and the structure of the first connecting shaft  181  and the structure of the second connecting shaft  161  are the same. So, it is convenient for production and processing. 
     In the implementation mode, in order to prevent the supporting bracket  150  from rotating too much around the connecting shaft to affect the smooth moving of the chassis, the chassis may also include the plate spring. The plate spring here is used for preventing the supporting bracket  150  from rotating too much around the connecting shaft. The way of arranging the plate spring here and the way of arranging the first plate spring  140  may be the same, and may also be different. 
     For example, as illustrated in  FIG. 4  to  FIG. 8 , when the supporting bracket  150  is connected with the support  110  by means of the first connecting shaft  181  and the second connecting shaft  161 , the chassis further includes a second plate spring and a third plate spring  170 . The middle of the second plate spring is fixed on the first connecting seat  180 . Two sides of the supporting bracket  150  with respect to the first connecting seat  180  are respectively provided with a third position limiting seat and a fourth position limiting seat. The third position limiting seat is provided with a third through groove mating with the first end of the second plate spring, and the fourth position limiting seat is provided with a fourth through groove mating with the second end of the second plate spring. The first end of the second plate spring is inserted in the third through groove and is capable of sliding in the third through groove, and the second end of the second plate spring is inserted in the fourth through groove and is capable of sliding in the fourth through groove. The middle of the third plate spring  170  is fixed on the second connecting seat  160 . Two sides of the supporting bracket  150  with respect to the second connecting seat  160  are respectively provided with a fifth position limiting seat  171  and a sixth position limiting seat  172 . The fifth position limiting seat  171  is provided with a fifth through groove  173  mating with the first end of the third plate spring  170 , and the sixth position limiting seat  172  is provided with a sixth through groove  174  mating with the second end of the third plate spring  170 . The first end of the third plate spring  170  is inserted in the fifth through groove  173  and is capable of sliding in the fifth through groove  173 , and the second end of the third plate spring  170  is inserted in the sixth through groove  174  and is capable of sliding in the sixth through groove  174 . 
     Here, the middle of the second plate spring, the first end of the second plate spring, the second end of the second plate spring, the third position limiting seat, the fourth position limiting seat, the third through groove and the fourth through groove respectively correspond to the middle of the first plate spring  140 , the first end of the first plate spring  140 , the second end of the first plate spring  140 , the first position limiting seat  141 , the second position limiting seat  142 , the first through groove  143  and the second through groove  144 . The above descriptions of the middle of the first plate spring  140 , the first end of the first plate spring  140 , the second end of the first plate spring  140 , the first position limiting seat  141 , the second position limiting seat  142 , the first through groove  143  and the second through groove  144  are also adaptable to the middle of the second plate spring, the first end of the second plate spring, the second end of the second plate spring, the third position limiting seat, the fourth position limiting seat, the third through groove and the fourth through groove, and will not be repeated here. 
     Here, the middle of the third plate spring  170 , the first end of the third plate spring  170 , the second end of the third plate spring  170 , the fifth position limiting seat  171 , the sixth position limiting seat  172 , the fifth through groove  173  and the sixth through groove  174  respectively correspond to the middle of the first plate spring  140 , the first end of the first plate spring  140 , the second end of the first plate spring  140 , the first position limiting seat  141 , the second position limiting seat  142 , the first through groove  143  and the second through groove  144 . The above descriptions of the middle of the first plate spring  140 , the first end of the first plate spring  140 , the second end of the first plate spring  140 , the first position limiting seat  141 , the second position limiting seat  142 , the first through groove  143  and the second through groove  144  are also adaptable to the middle of the third plate spring  170 , the first end of the third plate spring  170 , the second end of the third plate spring  170 , the fifth position limiting seat  171 , the sixth position limiting seat  172 , the fifth through groove  173  and the sixth through groove  174 , and will not be repeated here. 
     In the embodiments of the present disclosure, when the state of the supporting surface changes and one of the third wheel  103  and the fourth wheel  104  gets out of contact with the supporting surface, the out-of-contact one of the third wheel  103  and the fourth wheel  104  can rotate around the first rotating shaft  121  by means of the first crossbeam  130  to make contact with the supporting surface. The embodiments solve the problem of over-positioning phenomenon occurring between the chassis rigidly supported by four wheels and the supporting surface, so that the four wheels can contact with the supporting surface in the moving process, thus the running stability and security of the vehicle in moving is improved. 
     The embodiments of the present disclosure also provide a robot. The robot includes the chassis recorded in the above embodiments. 
     The above is only the specific implementation mode of the application and not intended to limit the scope of protection of the application. Any variations or replacements apparent to those skilled in the art within the technical scope disclosed by the application shall fall within the scope of protection of the application. Therefore, the scope of protection of the present disclosure shall be subject to the scope of protection of the claims.