A rescue and exploration robot of in-situ variable stiffness continuum

Abstract

The application provides an in-situ variable stiffness continuum rescue and detection robot, which comprises a main driving module, a first driving support, a second driving support, an outer spherical hinge and an inner spherical hinge, the first driving support and the second driving support are fixed on the first support and the second support of the main driving module respectively, the first end of the inner spherical hinge and the outer spherical hinge are fixed on the first driving support and the second driving support respectively, the inner spherical hinge and the outer spherical hinge are hollow, the inner spherical hinge is nested and penetrates through the outer spherical hinge, and the second driving support is used for conveying a driving alloy wire to be fixed on the outer spherical hinge surface and the end spherical hinge of the inner spherical hinge. The in-situ variable stiffness of the inner and outer spherical hinges can realize the in-situ movement of the whole robot, the inside of the ruins can be rescued and detected, and large bearing capacity can be provided while flexibility is maintained.

Description

Technical Field

[0001] This invention relates to the field of rescue robots, and in particular to an in-situ variable stiffness continuum rescue and detection robot. Background Technology

[0002] The inherent dangers, uncertainties, and time constraints of natural disaster sites pose significant challenges to rescue efforts. Three factors at disaster sites impact rescue operations: spatial constraints, structural instability, and hazardous materials. To improve search and rescue efficiency and better ensure the safety of rescue personnel, the research and development of continuous search and rescue robots with search and rescue modules, capable of adapting to unstructured environments, has become a new area of ​​focus for scientists.

[0003] For example, Chinese invention patent CN110561402A discloses a passively detachable snake-like robot, including a head, which includes a head shell and a control unit, an external environment detection unit, and a battery unit disposed on the head shell; and a body, which includes multiple detachable joint modules connected in sequence to form a chain structure and a joint drive motor disposed between two adjacent detachable joint modules; the detachable joint module includes module I, module II, and a connecting component; when a building collapses and is subjected to gravity compression, the compressed part stops moving, while the uncompressed part continues to move, transmitting power so that the spring in the connecting device drives the steel ball to disengage from the spherical groove, the compressed part separates from the whole, and terminates its work, while the uncompressed part continues to work under the guidance of the snake head, transmitting the disaster scene to rescue personnel through a miniature camera, improving the efficiency of rescue work. However, this invention faces the problems of multiple drives and complex control, and the detachable joints limit its movement flexibility.

[0004] For example, Chinese invention patent CN112276920A discloses a continuous snake-like robot, which includes a flexible body and a main controller. The flexible body is mainly composed of multiple flexible segments connected in series. Each flexible segment includes a cavity, a flexible shaft drive device, a top cover, a support frame, an angle sensor, and a controller. The flexible segments can perform movements such as extension, retraction, and bending. The main controller is installed at the tail of the flexible body. This invention applies the design of a parallel motion platform to the design of a continuous robot. Each flexible segment is equivalent to a parallel platform, which is flexible in movement, but faces the problems of multiple drives, complex control, and weak load-bearing capacity.

[0005] While existing continuum robots can achieve flexible movement in space, they face problems such as multiple drives and complex control. Continuum soft robots also suffer from insufficient structural rigidity and low load-bearing capacity. While solving the structural rigidity problem, they often face the problem of limited space for movement.

[0006] Most existing variable stiffness robotic arms do not yet integrate a drive system, and can only achieve switching between stiff and flexible states, or the drive system is difficult to achieve complex spatial postures. Finally, the manufacturing methods are relatively limited, and the structural complexity reduces the precision and strength of the robotic arm components, resulting in problems such as hysteresis. Summary of the Invention

[0007] To address the shortcomings of existing technologies, this invention provides a variable stiffness continuous robot for rescue exploration, capable of in-situ demolition. This effectively solves the problems of existing continuous robots' difficulty in multi-control operation and the inability of variable stiffness robots to achieve only stiff-flexible state switching, while failing to drive forward. This invention enables in-situ movement with variable stiffness, providing both flexibility and high load-bearing capacity.

[0008] The technical solution provided by this invention is as follows:

[0009] This invention provides an in-situ variable stiffness continuum rescue and exploration robot, comprising a main drive module, a first drive support, a second drive support, an outer ball joint, and an inner ball joint. The main drive module includes a base, a first drive motor, a second drive motor, a first lead screw, a second lead screw, a first support seat, and a second support seat. The first and second lead screws are mounted on the base and arranged in parallel. The first and second drive motors are respectively connected to the first and second lead screws. The first and second support seats are disposed above the base and are slidably connected to the base. The bottom of the first support seat and the first lead screw... The second drive support is fixedly connected to the first support, and includes a first pneumatic connector and a first push support. The first pneumatic connector is installed in the center hole of the first end face of the first push support. The second drive support is fixedly connected to the second support, and includes a second pneumatic connector, a second push support, and a wire feeding mechanism. The second pneumatic connector is installed in the side through hole of the boss on the first end face of the second push support, and the wire feeding mechanism is installed on the second end face of the second push support. The inner ball joint is nested inside the outer ball joint and passes through the outer ball joint. The inner ball joint includes an inner ball joint and an inner rubber joint. An integrated device for a rubber film and a sensor is provided. The inner ball joint is composed of inner ball joints connected in series. The inner ball joints located at the beginning and end of the inner ball joint are respectively the beginning ball joint and the end ball joint. The beginning ball joint is fixedly connected to a first push support. The sensor integrated device is mounted on the end ball joint. The inner rubber film is located inside the series of inner ball joints. The first end of the inner rubber film is adhered to the first push support, and the second end of the inner rubber film is adhered to the end ball joint. The outer ball joint includes a drive alloy wire, an outer ball joint, an outer rubber film, and a PU hose. The outer ball joint is composed of outer ball joints connected in series. The outer ball joints located at the beginning and end of the outer ball joint... The outer layer consists of an outer first-end ball joint and an outer last-end ball joint. The outer first-end ball joint is fixedly connected to a second pusher. A driving alloy wire passes through a through hole on the outer surface of the outer ball joint. The first end of the driving alloy wire is coiled on the wire feeding mechanism, and the second end of the driving alloy wire is fastened to the inner last-end ball joint. The PU hose is located inside the series-connected outer ball joints. The first end of the PU hose is fastened to the second pusher, and the second end of the PU hose is fastened to the outer last-end ball joint. The outer rubber film is located between the series-connected outer ball joints and the PU hose. The first end of the outer rubber film is adhered to the second pusher, and the second end of the outer rubber film is adhered to the outer last-end ball joint.

[0010] Preferably, the wire feeding mechanism includes a wire feeding motor, a wire feeding reel, a main wire feeding wheel, an auxiliary wire feeding wheel, a clamping rod, and a bracket. The first end of the driving alloy wire is coiled on the wire feeding reel. Both the main wire feeding wheel and the auxiliary wire feeding wheel are fitted with rubber rings. The driving alloy wire passes through the contact surfaces with the main wire feeding wheel and the auxiliary wire feeding wheel. The main wire feeding wheel is connected to the motor shaft via a key. The auxiliary wire feeding wheel is mounted on the clamping rod. The clamping force of the main wire feeding wheel and the auxiliary wire feeding wheel is controlled by adjusting the bolt at the end of the clamping rod. The wire feeding motor, the wire feeding reel, the main wire feeding wheel, the auxiliary wire feeding wheel, and the clamping rod are all mounted on the bracket. The bracket is fixed to the second push support by bolts.

[0011] Preferably, one end of both the outer and inner ball joints is provided with a plate-shaped protrusion, and the inner surface of the other end is provided with a concave tooth corresponding to the protrusion.

[0012] Preferably, slide rails are provided on both sides of the base, and both ends of the first support and the second support are slidably connected to the slide rails.

[0013] Preferably, the number of the wire feeding mechanisms is three, and they are arranged in an equilateral triangle on the second end face of the second drive support.

[0014] Preferably, the outer surface of the outer ball joint has three bosses with through holes evenly distributed.

[0015] Preferably, the size of the through hole is larger than the size of the drive alloy wire.

[0016] Preferably, the driving alloy wire is a nickel-titanium shape memory alloy wire.

[0017] Preferably, the first support base is positioned closer to the motor than the second support base.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. The in-situ variable stiffness continuum rescue and exploration robot of the present invention has a convex tooth at the front end of a single ball joint and a corresponding concave tooth on the inner surface of the rear end. When the ball joints are connected in series and the rubber diaphragm is inflated and pressurized, the concave and convex teeth mesh, restricting the rotation of the ball joint and realizing variable stiffness.

[0020] 2. The in-situ variable stiffness continuum rescue and exploration robot of the present invention has both flexible and rigid states in the inner and outer ball hinges. The inner and outer ball hinges are alternately variable stiffness by air inflation and pressurization. While switching between the rigid and flexible states, the flexible chain can also move along the trajectory of the rigid chain.

[0021] 3. The in-situ variable stiffness continuum rescue and exploration robot of the present invention uses nickel-titanium shape memory alloy wire to drive and guide the robot head, and the whole body moves forward on a predetermined trajectory, which greatly reduces the number of drives and simplifies the control strategy of the continuum robot. Attached Figure Description

[0022] Figure 1 This is an axonometric view of the overall structure of the in-situ variable stiffness continuum rescue and exploration robot of the present invention;

[0023] Figure 2 This is a schematic diagram of the main drive module of the in-situ variable stiffness continuum rescue and exploration robot of the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of the first drive support of the in-situ variable stiffness continuum rescue and exploration robot of the present invention;

[0025] Figure 4 This is a schematic diagram of the structure of the second drive support of the in-situ variable stiffness continuum rescue and exploration robot of the present invention;

[0026] Figure 5 This is a schematic diagram of the outer ball hinge structure of the in-situ variable stiffness continuum rescue and exploration robot of the present invention;

[0027] Figure 6 This is a schematic diagram of the inner ball hinge structure of the in-situ variable stiffness continuum rescue and exploration robot of the present invention;

[0028] Figure 7 This is a partial cross-sectional view of the in-situ variable stiffness continuum rescue and exploration robot of the present invention;

[0029] Figure 8 This is a schematic diagram of the wire feeding mechanism of the in-situ variable stiffness continuum rescue and exploration robot of the present invention;

[0030] Figure 9 This is a schematic diagram of the outer ball joint structure of the in-situ variable stiffness continuum rescue and exploration robot of the present invention.

[0031] Key reference numerals:

[0032] 1-Main drive module; 2-First drive support; 3-Second drive support; 4-Outer ball joint; 5-Inner 5-layer ball joint; 10-Base; 11-First drive motor; 12-First lead screw; 13-First support seat; 14-The

[0033] 15-Second drive motor; 16-Second lead screw; 21-First push support; 22-First pneumatic connector; 31-Second push support; 32-Second pneumatic connector; 33-Wire feeding mechanism; 41-Drive alloy wire; 42-Outer first end ball joint; 43-Outer ball joint; 44-Outer end ball joint; 45-Outer rubber film; 46-PU hose;

[0034] 51-Inner layer first end ball joint; 52-Inner layer ball joint; 53-Inner layer last end ball joint; 54-Inner layer rubber film; 55-Sensor integrated device; 331-Wire feeding motor; 332-Wire feeding disc; 333-Main wire feeding wheel; 334-Auxiliary wire feeding wheel; 335-Pressure rod; 336-Bracket; 431-Protruding tooth; 432-Concave tooth; 433-Through hole boss. Detailed Implementation

[0035] Hereinafter, exemplary embodiments, features, and aspects of the present invention will be described in detail with reference to the accompanying drawings. In the drawings, the same reference numerals denote elements with the same or similar functions, although various embodiments are shown in the drawings.

[0036] In this respect, however, unless otherwise specified, the accompanying drawings need not be drawn to scale.

[0037] See appendix Figures 1 to 9 The present invention provides a specific structure of an embodiment of the in-situ variable stiffness continuum rescue and exploration robot proposed in this invention. The robot includes a main drive module 1, a first drive support 2, a second drive support 3, an outer ball joint 4, and an inner ball joint 5.

[0038] The main drive module 1 includes a base 10, a first drive motor 11, a second drive motor 14, and a first wire.

[0039] The base 10 includes a first lead screw 12, a second lead screw 15, a first support base 13, and a second support base 16. Slide rails are provided on both sides of the base 10. The first lead screw 12 and the second lead screw 15 are arranged in parallel and are both installed in the middle of the base 10. The first drive motor 11 is connected to the first lead screw 12 via a coupling, and the second drive motor 14 is connected to...

[0040] The second lead screw 15 is connected. The first support seat 13 and the second support seat 16 are disposed above the base 10, and both ends of the first support seat 13 and the second support seat 16 are connected to the slide rail. The bottom of the first support seat 13 and...

[0041] The first lead screw 12 is connected, and the bottom of the second support 16 is connected to the second lead screw 15. The first support 13 is positioned closer to the motor than the second support 16.

[0042] The first drive support 2 includes a first pneumatic connector 22 and a first push support 21. The first push support 21 is fixedly connected to the first support 13. The first pneumatic connector 22 is installed in the center hole of the second end face of the first push support 21. A flange is provided on the first end face of the first push support 21.

[0043] The second drive support 3 includes a second pneumatic connector 32, a second push support 31, and a wire feeding mechanism 33. The second push support 31 is fixedly connected to the second support base 16. A boss is provided on the first end face of the second push support 31. The second pneumatic connector 32 is installed in the side through hole of the boss of the second push support 31. Three wire feeding mechanisms 33 are provided and are installed in an equilateral triangle on the second end face of the second push support 31.

[0044] The wire feeding mechanism 33 includes a wire feeding motor 331, a wire feeding disc 332, a main wire feeding wheel 333, an auxiliary wire feeding wheel 334, a clamping rod 335, and a bracket 336. One end of the drive alloy wire 41 is coiled on the wire feeding disc 332. The surfaces of the main wire feeding wheel 333 and the auxiliary wire feeding wheel 334 are both fitted with rubber rings. The drive alloy wire 41 passes through the contact surfaces with the main wire feeding wheel 333 and the auxiliary wire feeding wheel 334. The main wire feeding wheel 333 is connected to the motor shaft via a key. The auxiliary wire feeding wheel 334 is mounted on the clamping rod 335. The clamping force of the main wire feeding wheel 333 and the auxiliary wire feeding wheel 334 is controlled by adjusting the bolt at the end of the clamping rod 335. The wire feeding motor 331, the wire feeding disc 332, the main wire feeding wheel 333, the auxiliary wire feeding wheel 334, and the clamping rod 335 are all mounted on the bracket 336. The bracket 336 is fixed to the second push support 31 by bolts.

[0045] The inner ball hinge 5 is nested inside and through the outer ball hinge 4. The inner ball hinge 5 includes an inner ball hinge 52, an inner rubber film 54, and a sensor integration device 55. The inner ball hinge 5 is composed of inner ball hinges 52 connected in series. The inner ball hinges 52 located at the beginning and end of the inner ball hinge 5 are the inner beginning ball hinge 51 and the inner end ball hinge 53, respectively. The inner beginning ball hinge 51 is fastened to the end face of the flange of the first push support 21 by bolts. The sensor integration device 55 is installed on the inner end ball hinge 53. The inner rubber film 54 is located inside the series of inner ball hinges 52. One end of the inner rubber film 54 passes through the flange of the first push support 21 and is bonded to the second end face of the first push support 21. The other end of the inner rubber film 54 is bonded to the inner end ball hinge 53.

[0046] The outer ball joint 4 includes a drive alloy wire 41, an outer ball joint 43, an outer rubber film 45, and a PU hose 46. The outer ball joint 4 is composed of outer ball joints 43 connected in series. The outer ball joints 43 located at the beginning and end of the outer ball joint 43 are the outer beginning ball joint 42 and the outer end ball joint 44, respectively. The outer beginning ball joint 42 is fastened to the end face of the boss of the second push support 31 by bolts. One end of the drive alloy wire 41 passes through the through hole on the boss of the second push support 31 and is mounted on the wire feeding mechanism 33. The other end passes through the through hole on the outer surface of the outer ball joint 43 and is fastened to the inner end ball joint 53. The size of the through hole is larger than the size of the drive alloy wire 41. The PU hose 46 is located inside the series of outer ball joints 43. One end of the PU hose 46 passes through the boss of the second push support 31 and is fastened to the second end face of the second push support 31. The other end is fastened to the outer end ball joint 44. The outer rubber film 45 is located between the outer ball joint 43 and the PU hose 46 connected in series. One end of the outer rubber film 45 is bonded to the inner edge of the boss of the second push support 31, and the other end is bonded to the outer end ball joint 44.

[0047] The outer ball joint 43 has three through-hole bosses 433 evenly distributed on its surface, a plate-shaped tooth 431 at the front end, and a corresponding concave tooth 432 on the inner surface of the rear ball joint. Compared with the outer ball joint, the inner ball joint 52 does not have bosses with through holes on its surface, is smaller in size, and has the same structure otherwise.

[0048] When using the in-situ variable stiffness continuum rescue and detection robot of the present invention for rescue operations, the robot is first installed in front of the ruins to be detected. In the initial state, air is introduced through the first pneumatic connector 22 and the second pneumatic connector 32. The PU hose 46 isolates the inner and outer air chambers. The outer rubber film 45 and the inner rubber film 54 are inflated. The outer ball joint 43 and the inner ball joint 52 cannot rotate. The outer ball joint 4 and the inner ball joint 5 are adjusted to a rigid and straight state.

[0049] When the robot is running, the sensor integration device 55 acquires external information, releases air through the first pneumatic connector 22, the inner rubber film 54 recovers, the concave and convex teeth of the series inner ball joints 52 separate, the inner ball joints 52 can rotate, the inner ball joint chain 5 switches to a flexible state, the first drive motor 11 starts, drives the first lead screw 12 to rotate, thereby driving the first support seat 13 to move linearly, the first push support 21 is placed on the first support seat 13, the inner ball joint chain 5 is connected to the first push support 21, the first push support 21 pushes the entire flexible inner ball joint chain 5 to move on the fixed trajectory of the rigid outer ball joint chain 4. At this time, the wire feeding mechanism 33 moves in coordination. The wire feeding mechanism 33 is distributed in an equilateral triangle on the plane. One end of the driving alloy wire 41 is coiled on the wire feeding disc 332 and passes through the mating surface between the auxiliary wire feeding wheel 334 and the main wire feeding wheel 333. The clamping rod 335 adjusts the clamping force between the auxiliary wire feeding wheel 334 and the main wire feeding wheel 333. The driving alloy wire 41 passes through the through hole boss 433 on the second push support 31 and the outer ball joint 43. The other end is fastened to the inner end ball joint 53 of the inner ball joint chain 5. The wire feeding motor 331 drives the main wire feeding wheel 333 to rotate. Together with the auxiliary wire feeding wheel 334, it pulls the driving alloy wire 41, thereby guiding and driving the inner end ball joint 53 and controlling the forward direction.

[0050] After the inner ball hinge 5 completes the specified movement, the first pneumatic connector 22 takes in air, the inner rubber film 54 is inflated and expands, the concave and convex teeth of the series inner ball hinges 52 mesh, the inner ball hinges 52 cannot rotate, and the inner ball hinge 5 switches to a rigid state.

[0051] Then, the second pneumatic connector 32 releases air, the outer rubber film 45 recovers, the convex teeth 431 and concave teeth 432 on the series outer ball joint 43 separate, the outer ball joint 43 can rotate, the outer ball joint chain 4 switches to a flexible state, the second drive motor 14 starts, drives the second lead screw 15 to rotate, thereby driving the second support seat 16 to move linearly, the second push support 31 is placed on the second support seat 16, the outer ball joint chain 4 is connected to the second push support 31, the second push support 31 pushes the outer ball joint chain 4 in the flexible state to move on the fixed trajectory of the inner ball joint chain 5 in the rigid state.

[0052] Repeat the above operation, and by alternating the stiffness of the inner and outer ball joints 4, the robot can move in situ to carry out rescue exploration inside the ruins.

[0053] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An in-situ variable stiffness continuum rescue and exploration robot, characterized in that, It includes a main drive module, a first drive support, a second drive support, an outer ball joint, and an inner ball joint; The main drive module includes a base, a first drive motor, a second drive motor, a first lead screw, a second lead screw, a first support base, and a second support base. The first lead screw and the second lead screw are mounted on the base and arranged in parallel. The first drive motor and the second drive motor are respectively connected to the first lead screw and the second lead screw. The first support base and the second support base are disposed above the base and are slidably connected to the base. The bottom of the first support base is connected to the first lead screw, and the bottom of the second support base is connected to the second lead screw. The first drive support is fixedly connected to the first support base. The first drive support includes a first pneumatic connector and a first push support. The first pneumatic connector is installed in the center hole of the first end face of the first push support. The second drive support is fixedly connected to the second support base. The second drive support includes a second pneumatic connector, a second push support, and a wire feeding mechanism. The second pneumatic connector is installed in the side through hole of the boss on the first end face of the second push support, and the wire feeding mechanism is installed on the second end face of the second push support. The inner ball joint is nested inside and passes through the outer ball joint. The inner ball joint includes an inner ball joint, an inner rubber film, and a sensor integrated device. The inner ball joint is composed of inner ball joints connected in series. The inner ball joints located at the beginning and end of the inner ball joint are the inner beginning ball joint and the inner end ball joint, respectively. The inner beginning ball joint is fixedly connected to the first push support. The sensor integrated device is installed on the inner end ball joint. The inner rubber film is located inside the series of inner ball joints. The first end of the inner rubber film is adhered to the first push support, and the second end of the inner rubber film is adhered to the inner end ball joint. The outer ball joint chain includes a drive alloy wire, an outer ball joint, an outer rubber film, and a PU hose. The outer ball joint chain is composed of outer ball joints connected in series. The outer ball joints located at the beginning and end of the outer ball joint chain are the outer beginning ball joint and the outer end ball joint, respectively. The outer beginning ball joint is fixedly connected to the second push support. The drive alloy wire passes through the through hole on the outer surface of the outer ball joint. The first end of the drive alloy wire is coiled on the wire feeding mechanism, and the second end of the drive alloy wire is fastened to the inner end ball joint. The PU hose is located inside the series-connected outer ball joints. The first end of the PU hose is fastened to the second push support, and the second end of the PU hose is fastened to the outer end ball joint. The outer rubber film is located between the series-connected outer ball joints and the PU hose. The first end of the outer rubber film is adhered to the second push support, and the second end of the outer rubber film is adhered to the outer end ball joint.

2. The in-situ variable stiffness continuum rescue and exploration robot according to claim 1, characterized in that, The wire feeding mechanism includes a wire feeding motor, a wire feeding reel, a main wire feeding wheel, an auxiliary wire feeding wheel, a clamping rod, and a bracket. The first end of the driving alloy wire is coiled on the wire feeding reel. Both the main and auxiliary wire feeding wheels are fitted with rubber rings. The driving alloy wire passes through the contact surfaces with the main and auxiliary wire feeding wheels. The main wire feeding wheel is connected to the motor shaft via a key. The auxiliary wire feeding wheel is mounted on the clamping rod. The clamping force of the main and auxiliary wire feeding wheels is controlled by adjusting the bolt at the end of the clamping rod. The wire feeding motor, wire feeding reel, main wire feeding wheel, auxiliary wire feeding wheel, and clamping rod are all mounted on the bracket. The bracket is fixed to the second push support by bolts.

3. The in-situ variable stiffness continuum rescue and exploration robot according to claim 1, characterized in that, Both the outer and inner ball joints have plate-shaped protruding teeth at one end, and concave teeth corresponding to the protruding teeth are provided on the inner surface of the other end.

4. The in-situ variable stiffness continuum rescue and exploration robot according to claim 1, characterized in that, The base is provided with slide rails on both sides, and both ends of the first support and the second support are slidably connected to the slide rails.

5. The in-situ variable stiffness continuum rescue and exploration robot according to claim 2, characterized in that, The number of wire feeding mechanisms is three, and they are arranged in an equilateral triangle on the second end face of the second drive support.

6. The in-situ variable stiffness continuum rescue and exploration robot according to claim 1, characterized in that, The outer surface of the outer ball joint has three bosses with through holes evenly distributed.

7. The in-situ variable stiffness continuum rescue and exploration robot according to claim 6, characterized in that, The size of the through hole is larger than the size of the drive alloy wire.

8. The in-situ variable stiffness continuum rescue and exploration robot according to claim 1, characterized in that, The driving alloy wire is a nickel-titanium shape memory alloy wire.

9. The in-situ variable stiffness continuum rescue and exploration robot according to claim 1, characterized in that, The first support is positioned closer to the motor than the second support.

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