Robot walking device and anti-overturning control method

Abstract

The robot walking device comprises a chassis, the chassis is provided with a mechanical arm used for grabbing objects, the chassis comprises a main control board, a support and four driving wheels arranged at the four corners of the support, the support comprises a front end and a rear end which are telescopically connected, and the driving wheels and the mechanical arm are both in data communication with a driving board. The bracket is provided with a pressure sensor aiming at each driving wheel; when the mechanical arm works, the pressure sensor detects the pressure borne by each driving wheel in real time so as to judge the gravity center change of the robot walking device, and when the gravity center of the robot walking device is about to exceed the supporting range, the driving mechanism drives the rear end to move in the direction away from the front end so as to expand the supporting range, so that the gravity center is kept within the supporting range. The robot is prevented from overturning.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite mobile operation devices, in particular to a robot walking device and an anti-overturning control method. BACKGROUND

[0002] At present, composite robots, especially those with omni-directional mobile chassis such as Mecanum wheels, are increasingly widely used in warehouse logistics, intelligent manufacturing, security inspection, special operation and other fields. However, in the actual application process, the problem of dynamic stability seriously restricts its performance and safety, including the risk of overturning caused by the shift of the center of gravity due to the following reasons:

[0003] 1) When the mechanical arm is greatly extended to the outer edge of the chassis, the overall center of gravity of the robot system will shift significantly;

[0004] 2) When the mechanical arm end grasps or carries an object with considerable weight, the weight and position change of the load will instantaneously change the center of gravity of the robot

[0005] 3) When on a slope, uneven ground or subjected to a slight external collision, the change of the chassis posture may also cause the center of gravity to be unstable.

[0006] The existing technology lacks real-time perception and active adjustment strategy for the existing problems. Even if some systems can detect tilting, the usual response is to stop moving or retract the mechanical arm, which seriously disrupts the work process and reduces efficiency; in addition, the inherent characteristics of Mecanum wheels rotating in place are not fully utilized. The direct consequences are that the robot's working range is limited, the efficiency is reduced, and there are serious safety hazards, ultimately limiting the promotion and application of such robots in more complex and efficient scenarios. SUMMARY

[0007] The present application provides a robot walking device and an anti-overturning control method, which can calculate the positional relationship between the current center of gravity position and the actual support range in real time, and change the position and size of the actual support range so that the center of gravity position is in a safe position, providing options for breaking through the current technical bottleneck, meeting market demand and optimizing products.

[0008] A robot walking device for carrying a mechanical arm that can grasp heavy objects, comprising a chassis and a mechanical arm, the mechanical arm being arranged on the chassis, the chassis comprising a main control board, a support and four drive wheels arranged at the four corners of the support, the drive wheels and the mechanical arm being in data communication with the main control board;

[0009] The support is provided with a pressure sensor for each driving wheel, and the pressure sensor detects the pressure received by each driving wheel in real time when the mechanical arm is working, so as to determine the change of the gravity center of the robot walking device; the range in which the robot walking device does not overturn when taking an object by the mechanical arm constitutes the support range;

[0010] The mechanical arm is of a multi-section structure, and the joints between some sections are provided with joint motors, and the main control board controls the joint motors to work, so that the mechanical arm can complete the action of stretching out of the support range to grab heavy objects and returning;

[0011] The support includes a front end and a rear end, the front end is provided with a sliding rail, and the rear end is provided with a driving mechanism, the driving mechanism is connected with the sliding rail to drive the rear end to extend and retract relative to the front end, so as to change the support range;

[0012] When taking an object, when the gravity center of the robot walking device is about to exceed the support range, the driving mechanism drives the rear end to move away from the front end, so as to expand the support range, so that the gravity center remains within the support range, so as to prevent the robot from overturning.

[0013] Further, when taking heavy objects, the main control board calculates the direction of the movement of the gravity center in real time according to the pressure sensor, when the gravity center is close to the boundary of the support range, the main control board controls the driving wheel to drive the support to rotate, so that the direction of the extension and retraction of the support is parallel or tends to be parallel to the direction of the movement of the gravity center.

[0014] Further, when the gravity center continues to move towards the boundary of the support range, the main control board controls the driving mechanism to move, so that the front end is elongated relative to the rear end, so that the gravity center remains within the support range.

[0015] Further, when the front end and the rear end have moved to the relatively longest position, if the gravity center is still moving towards the boundary of the support range, the main control board issues an alarm to stop the grabbing action of the mechanical arm.

[0016] Further, the support range is a range covered by extending the length of two sides of a rectangle or a square formed by the four driving wheels by 50%.

[0017] Further, the support is also provided with an IMU sensor, which can monitor the overturning angle of the support, when the overturning angle of the support is greater than an angle threshold, the main control board drives the driving wheel to drive the support to rotate and / or the main control board drives the front end to elongate relative to the rear end by the driving mechanism, so as to avoid the robot walking device from overturning.

[0018] Furthermore, when used for towing objects, if the center of gravity does not exceed the support range and the IMU sensor detects acceleration in the traction direction, the main control board determines that the current traction state is safe; if the center of gravity is about to exceed the support range and the IMU sensor does not detect acceleration in the traction direction, the main control board stops the traction action of the robot walking device and issues an alarm.

[0019] An anti-tipping control method, applicable to robot walking devices as described above, includes the following steps:

[0020] S1. Start the robot's walking device. The main control board drives the robotic arm to extend and grasp the object.

[0021] S2. During the process of the robotic arm grasping the object, the center of gravity position of the robot's walking device is calculated in real time, as follows:

[0022] Establish a coordinate system with the geometric center of the support in its current state as the origin, and calculate the position of the center of gravity of the robot's walking device in its current state. The x-coordinate of the center of gravity is:

[0023] x cg =(F fl x fl +F fr x fr +F rl x rl +F rr x rr ) / W

[0024] The ordinate of the centroid position is:

[0025] y cg =(F fl y fl +F fr y fr +F rl y rl +F rr y rr ) / W

[0026] Where W = F fl +F fr +F rl +F rr And F fl For the pressure on the left front wheel, F fr For the pressure on the right front wheel, F rl For the pressure on the left rear wheel, F rr The pressure of the right rear wheel is; the contact coordinate of the left front wheel is (x fl ,y fl The coordinates of the right front wheel contacting the ground are (x fr ,y fr The left rear wheel's contact coordinates are (x...).rl , y rl , y rr , y rr );

[0027] S3, calculating the shortest distance d between the current barycenter position and the boundary of the support range min , comparing the size between d and the distance threshold value D; min

[0028] If d min >D, the main control board continues to drive the mechanical arm to grab the object;

[0029] If d min <D, the main control board drives the rear end to move away from the front end through the driving mechanism to expand the support range, until d min >D.

[0030] Further, the following steps are further included:

[0031] If d min <D, the main control board controls the support to rotate an angle a in the first direction through the driving wheel, so that the front end and the rear end of the support are parallel or tend to be parallel to the direction of the barycenter movement, and then the size between d and the distance threshold value D is compared again, if d min >D, the main control board continues to drive the mechanical arm to grab the object. min

[0032] Further, during the movement of the mechanical arm, if d min <D again, and at this time the rear end is driven by the main control board to move away from the front end to the maximum position, the main control board stops the mechanical arm and issues a warning, and after the staff adjusts and confirms that there is no error, the robot walking device is started again.

[0033] The beneficial effects of the present application are:

[0034] 1. The robot walking device provided by the present application comprises a chassis, the chassis is provided with a mechanical arm for grabbing objects, the chassis comprises a main control board, a support and four driving wheels arranged at four corners of the support, the support comprises a front end and a rear end connected in an extendable manner, the driving wheels and the mechanical arm are in data communication with the main control board, and the support is provided with a pressure sensor for each driving wheel; when the mechanical arm works, the pressure sensor detects the pressure received by each driving wheel in real time to determine the change of the barycenter of the robot walking device, when the barycenter of the robot walking device is about to exceed the support range, the driving mechanism drives the rear end to move away from the front end to expand the support range, so that the barycenter is kept within the support range, thereby preventing the robot from overturning.

[0035] ​​2、The robot walking device provided by the application, when the rear end moves to the limit position in the direction away from the front end, and the center of gravity position still exceeds the support range, the main control board sends an alarm to stop the grabbing action of the grabbing mechanism, to avoid the robot walking device from falling.

[0036] 3、The robot walking device provided by the application, the chassis is further provided with an IMU sensor, which can monitor the overturning angle of the chassis, when the overturning angle of the chassis is greater than the angle threshold, the main control board drives the driving wheel to drive the support to rotate and / or the main control board drives the rear end to move in the direction away from the front end through the driving mechanism, to avoid the robot walking device from overturning; the center of gravity monitoring and angle monitoring work together to prevent the robot walking device from overturning.

[0037] 4、The robot walking device provided by the application can be used to tow objects, by judging whether the center of gravity exceeds the support range, and whether there is acceleration in the towing direction detected by the IMU sensor, to judge whether the current robot walking device has the risk of overturning, if so, the main control board stops the towing action of the robot walking device and sends an alarm.

[0038] 5、The anti-overturning control method provided by the application is suitable for the robot walking device described above, to make the robot walking device more intelligent, the control method adopts the control process of "perception-judgment-adjustment", through calculation to "perceive" the current center of gravity position in real time, and through "judgment" of the size between the distance of the center of gravity in its offset direction and the boundary of the actual support range and the distance threshold, finally through driving the chassis to rotate and / or driving the first disc body and the second disc body to expand to "adjust" the position and size of the actual support range, so that the robot walking device has wider effective working range, stronger load applicability, better working continuity and efficiency and better terrain applicability. BRIEF DESCRIPTION OF DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, below will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description only some embodiments of the application, and for those skilled in the art, without creative labor, can also obtain other drawings according to these drawings.

[0040] Figure 1 is a schematic view of a robot walking device of the application;

[0041] Figure 2 is a top view of a robot walking device of the application;

[0042] Figure 3 is a schematic view of the chassis rotation of a robot walking device of the application;

[0043] Figure 4 A chassis telescopic diagram of a robot walking device of the present application;

[0044] Figure 5 A coordinate system diagram of a robot walking device of the present application;

[0045] Figure 6 A logic diagram of a anti-overturning control method of the present application;

[0046] In the figure, 10, support; 101, front end; 102, rear end; 20, drive wheel; 30, mechanical arm; 301, support section; 302, working section; 303, execution section; 40, pressure sensor; 50, support range. DETAILED DESCRIPTION

[0047] The present application will be described in detail below. Figures 1-6 The present application will be described in detail below.

[0048] A robot walking device for carrying a mechanical arm 30 capable of grabbing heavy objects to walk, comprising a chassis and a mechanical arm 30, the mechanical arm 30 is arranged on the chassis, the chassis comprises a main control board, a support 10 and four drive wheels 20 arranged at the four corners of the support, the drive wheels 20 and the mechanical arm 30 are in data communication with the main control board;

[0049] The support 10 is respectively provided with a pressure sensor 40 for each drive wheel, when the mechanical arm 30 works, the pressure sensor 40 detects the pressure received by each drive wheel 20 in real time, so as to judge the change of the center of gravity of the robot walking device; the range of the center of gravity in which the robot walking device does not overturn when taking an object by the mechanical arm 30 constitutes a support range;

[0050] The mechanical arm 30 is of a multi-section structure, and the connection between some sections is provided with a joint motor, the main control board controls the joint motor to work so that the mechanical arm 30 can complete the action of stretching out of the support range 50 to grab heavy objects and retracting;

[0051] The support 10 comprises a front end 101 and a rear end 102, the front end 101 is provided with a slide rail, and the rear end 102 is provided with a driving mechanism, the driving mechanism is connected with the slide rail to drive the rear end 102 to move telescopically relative to the front end 101, so as to change the support range 50;

[0052] When taking an object, if the center of gravity of the robot walking device is about to exceed the support range 50, the driving mechanism drives the rear end 102 to move away from the front end 101, so as to expand the support range 50, so that the center of gravity is kept within the support range 50, so as to prevent the robot from overturning.

[0053] When picking up the heavy object, the main control board calculates the direction of the center of gravity in real time according to the pressure sensor 40, and when the center of gravity is close to the boundary of the support range 50, the main control board controls the driving wheel 20 to drive the support 10 to rotate, so that the direction of the telescopic movement of the support 10 is parallel or tends to be parallel to the direction of the movement of the center of gravity. When the center of gravity continues to move towards the boundary of the support range 50, the main control board controls the driving mechanism to move, so that the front end 101 is elongated relative to the rear end 102, so that the center of gravity remains within the support range 50. When the front end 101 and the rear end 102 have moved to the relatively longest position, if the center of gravity is still moving towards the boundary of the support range 50, the main control board issues an alarm and stops the grabbing action of the mechanical arm 30.

[0054] In this embodiment, the support range 50 is obtained on the basis of the area formed by the four driving wheels 20 being connected to each other, and is enlarged, reduced or kept unchanged based on the height of the robot walking device or the weight of the support 10. Specifically, when the support 10 is heavy and the mechanical arm 30 is arranged at a low height, the stability of the robot walking device is good, and the support range 50 can be obtained by expansion. In order to avoid excessive expansion, the support range 50 is the range covered by the length of 50% outward expansion of the two adjacent sides of the quadrilateral formed by the four driving wheels 20 being connected to each other, as shown in FIG. 2B. In other embodiments, when the position of the mechanical arm 30 is high, the risk of overturning of the robot walking device increases, and the support range 50 is reduced on the basis of the area formed by the four driving wheels 20 being connected to each other, to ensure safety. Figure 2

[0055] The mechanical arm 30 includes a support section 301 and a plurality of working sections 302 connected to each other in rotation, the working section 302 at the first end is rotatably connected to the support end, the working section at the last end is provided with an execution section 303 for grabbing objects, a joint motor is arranged between the support section 301 and the working section 302 and between the two working sections 302, and the main control board drives the mechanical arm 30 to stretch or contract through the joint motor; a compensation motor is arranged between the support section 301 and the support 10, and the main control board drives the support section 301 to rotate an angle a in the second direction through the compensation motor to offset the angle a rotated by the support 10 in the first direction, so that the grabbing position of the mechanical arm 30 does not change, wherein the rotation directions of the first direction and the second direction are opposite.

[0056] The support 10 is also provided with an IMU sensor, which can monitor the overturning angle of the support 10. When the overturning angle of the support 10 is greater than an angle threshold, the main control board drives the driving wheel 20 to drive the support 10 to rotate and / or the main control board drives the front end 101 to move in a direction away from the rear end 102 through the driving mechanism, so as to avoid the robot walking device from overturning.

[0057] ​The robot walking device can also be used for towing an object. When the gravity center does not exceed the support range, and the IMU sensor detects that there is acceleration in the towing direction, the main control board determines that the current towing state is safe. When the gravity center is about to exceed the support range, and the IMU sensor does not detect that there is acceleration in the towing direction, the main control board stops the towing action of the robot walking device and issues an alarm.

[0058] The application also provides an anti-overturning control method, as shown in the accompanying drawings, which is suitable for the robot walking device described above, and comprises the following steps. Figure 6

[0059] S1, starting the robot walking device, and the main control board drives the mechanical arm 30 to stretch to grasp the object;

[0060] S2, during the process in which the mechanical arm 30 grasps the object, the gravity center position is calculated in real time, as follows:

[0061] The geometric center in the current state of the support 10 is taken as the coordinate origin to establish a coordinate system, as shown in the accompanying drawings, and the gravity center position of the robot walking device in the current state is calculated. The horizontal coordinate of the gravity center position is: Figure 5

[0062] x cg =(F fl x fl +F fr x fr +F rl x rl +F rr x rr ) / W

[0063] The vertical coordinate of the gravity center position is:

[0064] y cg =(F fl y fl +F fr y fr +F rl y rl +F rr y rr ) / W

[0065] wherein W=F fl +F fr +F rl +F rr , F fl is the left front wheel pressure, F fr is the right front wheel pressure, F rl is the left rear wheel pressure, and F rr is the right rear wheel pressure; the left front wheel contact coordinate is (x fl ,y fl ​​), the left front wheel touch ground coordinates are (x fr ,y fr ), the right rear wheel touch ground coordinates are (x rl ,y rl ), and the left rear wheel touch ground coordinates are (x rr ,y rr );

[0066] S3, calculating the shortest distance d min between the current barycenter position and the boundary of the support range 50, and comparing the size between d min and the distance threshold D;

[0067] If d min >D, the main control board continues to drive the mechanical arm 30 to grab the object;

[0068] If d min <D, the main control board drives the front end to move away from the rear end through the driving mechanism to expand the support range 50 until d min >D.

[0069] The anti-overturning control method further comprises the following steps:

[0070] S4, if d min <D, the main control board controls the support 10 to rotate in place by an angle a in the first direction through the driving wheel 20, and simultaneously, the main control board drives the mechanical arm 30 to rotate by an angle a in the second direction, so that the extension direction of the front end 101 and the rear end 102 is parallel or tends to be parallel to the moving direction of the barycenter position, and the size between d min and the distance threshold D is compared again;

[0071] S5, during the movement of the mechanical arm 30, if d min <D appears again, and at this time, the front end 101 and the rear end 102 move to the maximum position, the main control board stops the mechanical arm 30 and issues an alarm, and after the staff adjusts and confirms that there is no error, the robot walking device is started again.

[0072] The anti-overturning control method proposed in the embodiment is to first drive the front end 101 and the rear end 102 to extend and retract to expand the support range 50, and then drive the support 10 to rotate; or first drive the support 10 to rotate, and then drive the front end 101 and the rear end 102 to extend and retract to expand the support range 50; or the extension and rotation of the support 10 are performed simultaneously.

[0073] The anti-overturning control method makes the robot walking device more intelligent. The control method adopts a control process of "perception-judgment-adjustment", calculates the current gravity center position in real time to "perceive" the current gravity center position, judges the size between the distance of the gravity center from the boundary of the support range 50 in the offset direction and the distance threshold, and finally adjusts the position and size of the support range 50 by driving the support 10 to rotate and / or driving the front end 101 and the rear end 102 to expand, so that the robot walking device has a wider effective working range, stronger load applicability, better working continuity and efficiency, and better terrain applicability.

[0074] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A robot walking device for carrying a manipulator arm that can grasp a heavy object to walk, comprising a chassis and a manipulator arm, the manipulator arm being provided on the chassis, characterized by, The chassis comprises a main control board, a support and four driving wheels arranged at four corners of the support, the driving wheels and the mechanical arm are in data communication with the main control board; The support is respectively provided with a pressure sensor for each driving wheel, when the mechanical arm works, the pressure sensor detects the pressure received by each driving wheel in real time to determine the change of the gravity center of the robot walking device; the range of the gravity center in which the robot walking device does not overturn when taking objects by the mechanical arm constitutes a support range; The mechanical arm is a multi-section structure, the joints between some sections are provided with joint motors, the main control board controls the joint motors to work so that the mechanical arm can complete the action of stretching out of the support range to grab heavy objects and returning; The support comprises a front end and a rear end, the front end is provided with a sliding rail, the rear end is provided with a driving mechanism, the driving mechanism is connected with the sliding rail to drive the rear end to stretch and retract relative to the front end to change the support range; When taking objects, when the gravity center of the robot walking device is about to exceed the support range, the driving mechanism drives the rear end to move away from the front end to expand the support range, so that the gravity center remains within the support range to prevent the robot from overturning.

2. The robotic walking device of claim 1, wherein, When taking heavy objects, the main control board calculates the direction of the movement of the gravity center in real time according to the pressure sensor, when the gravity center is close to the boundary of the support range, the main control board controls the driving wheels to drive the support to rotate, so that the direction of the stretch and retraction of the support is parallel or tends to be parallel to the direction of the movement of the gravity center.

3. The robotic walking device of claim 2, wherein, When the gravity center continues to move towards the boundary of the support range, the main control board controls the driving mechanism to move, so that the front end elongates relative to the rear end, so that the gravity center remains within the support range.

4. The robotic walking device of claim 3, wherein, When the front end and the rear end have moved to the relatively longest position, if the gravity center is still moving towards the boundary of the support range, the main control board issues an alarm to stop the grabbing action of the mechanical arm.

5. The robotic walking device of claim 1, wherein, The support range is the range covered by the two sides of the rectangle or square formed by the four driving wheels, which are respectively extended outward by 50% of the length.

6. A robotic walking device according to any one of claims 1-5, characterized in that, The support is also provided with an IMU sensor to monitor the overturning angle of the support, when the overturning angle of the support is greater than an angle threshold, the main control board drives the driving wheels to rotate the support and / or the main control board drives the front end to elongate relative to the rear end through the driving mechanism to avoid the robot walking device from overturning.

7. The robotic walking device of claim 6, wherein, When pulling objects, when the gravity center does not exceed the support range, and the IMU sensor detects that there is acceleration in the pulling direction, the main control board determines that the current pulling state is safe; When the gravity center is about to exceed the support range, and the IMU sensor does not detect that there is acceleration in the pulling direction, the main control board stops the pulling action of the robot walking device and issues an alarm.

8. A roll-over prevention control method suitable for use with the robotic walking device of any one of claims 1-7, characterized by, The method comprises the following steps: S1, starting the robot walking device, the main control board drives the mechanical arm to stretch to grab objects; S2, during the process of the mechanical arm grabbing the object, the gravity center position of the robot walking device is calculated in real time, as follows: The coordinate system is established with the geometric center of the support in the current state as the coordinate origin, and the gravity center position of the robot walking device in the current state is calculated, the horizontal coordinate of the gravity center position is: x cg = (F fl x fl + F fr x fr + F rl x rl + F rr x rr ) / W The vertical coordinate of the gravity center position is: y cg = (F fl y fl + F fr y fr + F rl y rl + F rr y rr ) / W where W = F fl +F fr +F rl +F rr , and F fl is the left front wheel pressure, F fr is the right front wheel pressure, F rl is the left rear wheel pressure, and F rr is the right rear wheel pressure; the left front wheel ground contact coordinates are (x fl , y fl ), the right front wheel ground contact coordinates are (x fr , y fr ), the left rear wheel ground contact coordinates are (x rl , y rl ), and the right rear wheel ground contact coordinates are (x rr , y rr ). S3, compute the shortest distance d between the current barycenter position and the support range boundary min , compare the size between d min and the distance threshold D; If d min D, then the master board continues to drive the robot arm to grab the object; If d min <D, the main control board drives the rear end to move away from the front end through the driving mechanism to expand the support range until d min >D.

9. The roll-over control method of claim 8 wherein, Further comprising the following steps: If d min <D, the main control board controls the driving wheel to rotate the support in place by an angle a in a first direction, so that the telescopic direction of the front end and the rear end is parallel or tends to be parallel to the direction of the center of gravity movement. Again, the size between d min and the distance threshold value D is compared, if d min >D, the main control board continues to drive the mechanical arm to grab the object.

10. The roll-over control method of claim 9, wherein, During the movement of the mechanical arm, if d min D appears again, and at this time the main control board drives the rear end to move to the maximum position away from the front end, the main control board stops the mechanical arm and issues an alarm, and after the staff adjusts and confirms that there is no error, the robot walking device is started again.

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