Synchronous rotation control system for mobile robots and corresponding robots and methods

Abstract

A synchronous rotation control system and corresponding method for a mobile robot, a mobile robot, a computer device, and a storage medium are disclosed. The system includes a controller, an inertial measurement unit (IMU), a wheel odometer module, and a pallet synchronous rotation actuator. The IMU is configured to measure in real-time a first angular velocity W1 of the mobile robot's chassis rotating about a vertical axis. The wheel odometer module includes first and second speed sensors configured to measure in real-time a first speed V1 of a first differential wheel and a second speed V2 of a second differential wheel, respectively, and is configured to calculate and transmit the second angular velocity W2 of the chassis rotating about the vertical axis based on V1 and V2. The controller is configured to control the pallet synchronous rotation actuator based at least on W1 and W2, such that when the mobile robot's chassis rotates by an angle in a rotation direction, the pallet synchronous rotation actuator controls the mobile robot's rotatable pallet to synchronously rotate by the same angle in the opposite direction of rotation.

Description

Technical Field

[0001] This invention relates to the field of mobile robots, and more specifically, to a synchronous rotation control system for a mobile robot, a method for synchronous rotation control of a mobile robot, a corresponding mobile robot, a computer device, and a non-transitory computer-readable storage medium. Background Technology

[0002] Mobile robots have the ability to move around in their environment and are not fixed in any physical location. A mobile robot can be, for example, an "autonomous mobile robot" (AMR), meaning it can navigate in uncontrolled environments without physical or electromechanical guidance devices. Alternatively, a mobile robot can also be, for example, an automated guided vehicle (AGV) that relies on guidance devices to allow the mobile robot to travel along a predetermined navigation route in a relatively controlled space.

[0003] Mobile robots have become increasingly common in commercial and industrial environments. Particularly in the logistics and warehousing industry, mobile robots are being used more and more to efficiently transport goods.

[0004] In logistics and warehousing applications, mobile robots inevitably encounter narrow workspaces such as T-shaped and L-shaped layouts. In these situations, mobile robots transporting goods face difficulties turning. To address this issue, mobile robots with synchronous rotation capabilities have been developed. During rotation, the rotatable pallet of such a mobile robot can adjust its angle relative to the robot's chassis in real time, achieving the effect of the chassis rotating while the rotatable pallet remains stationary relative to the ground. For example, CN 109308071A discloses a transport trolley with a lifting and rotating mechanism. This transport trolley has a synchronous rotation mechanism between its lifting disc and lifting drive device. Under the synchronous rotation drive of this mechanism, the lifting disc keeps the rack stationary relative to the bottom surface, improving the stability of the rack during straight-line travel and rotation.

[0005] However, currently, existing mobile robots mainly employ rotation angle calculation methods based solely on inertial measurement units (IMUs) or solely on wheeled odometer modules (ODOMs). Using either of these methods alone has its drawbacks. This is because IMUs may accumulate errors over long periods of operation, and wheeled odometer modules are susceptible to environmental influences that can render measurement data inaccurate. For example, slippage of the robot's differential wheels due to wet ground can lead to inaccurate data calculated by the wheeled odometer module.

[0006] Therefore, an improved synchronous rotation control system for mobile robots is needed. Summary of the Invention

[0007] The purpose of this invention is to solve or at least alleviate some of the problems described above in the prior art.

[0008] According to one aspect of the present invention, a synchronous rotation control system for a mobile robot is provided, the mobile robot having a chassis and a rotatable tray, the chassis being equipped with a first differential wheel and a second differential wheel, the synchronous rotation control system comprising a controller, an inertial measurement unit, a wheel odometer module, and a tray synchronous rotation actuator; wherein,

[0009] The inertial measurement unit is configured to measure in real time the first angular velocity W1 of the chassis of the mobile robot rotating about a vertical axis perpendicular to the ground and send the first angular velocity W1 to the controller;

[0010] The wheeled odometer module includes a first speed sensor and a second speed sensor. The first and second speed sensors are configured to measure, in real time, the first speed V1 and the second speed V2 of the first differential wheel of the mobile robot's chassis, respectively. The wheeled odometer module is configured to calculate, in real time, the second angular velocity W2 of the mobile robot's chassis rotating about the vertical axis based on the first speed V1 and the second speed V2, and send the second angular velocity W2 to the controller.

[0011] The controller is configured to communicatively connect to the inertial measurement unit, the wheel odometer module, and the pallet synchronous rotation actuator to control the pallet synchronous rotation actuator based at least on the first angular velocity W1 and the second angular velocity W2 of the chassis, such that when the chassis of the mobile robot rotates by an angle along a rotation direction, the pallet synchronous rotation actuator controls the rotatable pallet of the mobile robot to synchronously rotate by the same angle in the opposite direction of the rotation direction.

[0012] According to a second aspect of the present invention, a mobile robot is provided, comprising:

[0013] Synchronous rotation control system according to the first aspect of the present invention;

[0014] Chassis;

[0015] A first differential wheel and a second differential wheel are mounted on the chassis;

[0016] A rotatable pallet, connected to the chassis via a pallet synchronous rotation actuator and configured to be driven to rotate by the pallet synchronous rotation actuator; and

[0017] A chassis drive, which is mounted to the chassis and configured to drive the first differential wheel and the second differential wheel.

[0018] According to a third aspect of the present invention, a method for synchronous rotation control of a mobile robot is provided, wherein the mobile robot includes a synchronous rotation control system, a chassis, and a rotatable tray, the chassis being equipped with a first differential wheel and a second differential wheel, the synchronous rotation control system including a controller, an inertial measurement unit, a wheel odometer module, and a tray synchronous rotation actuator, the method comprising:

[0019] The inertial measurement unit measures in real time the first angular velocity W1 of the mobile robot's chassis rotating about a vertical axis perpendicular to the ground;

[0020] The second angular velocity W2 of the mobile robot's chassis rotating around the vertical axis is calculated in real time based on the first speed V1 of the first differential wheel and the second speed V2 of the second differential wheel measured in real time by the first speed sensor and the second speed sensor of the wheel-type odometer module, respectively; and

[0021] The controller controls the pallet synchronous rotation actuator based at least on the first angular velocity W1 and the second angular velocity W2, such that when the chassis of the mobile robot rotates by an angle along a rotation direction, the pallet synchronous rotation actuator controls the rotatable pallet to synchronously rotate by the same angle in the opposite direction of the rotation direction.

[0022] According to a fourth aspect of the present invention, a computer device is provided, including a memory and a processor, wherein computer instructions are stored in the memory, and when executed by the processor, the computer instructions cause the method for synchronous rotation control of a mobile robot according to a third aspect of the present invention to be executed.

[0023] According to a fifth aspect of the invention, a non-transitory computer-readable storage medium is provided, on which computer instructions are stored, which, when executed by a processor, cause the method for synchronous rotation control of a mobile robot according to a third aspect of the invention to be executed.

[0024] The solution of the present invention integrates the rotation angle calculation method based on the inertial measurement unit and the rotation angle calculation method based on the wheel odometer module, thereby avoiding the defects of using either of the above rotation angle calculation methods alone. That is, it avoids cumulative errors and improves control accuracy. Attached Figure Description

[0025] Non-limiting and non-exhaustive embodiments of the invention are described by way of example with reference to the following figures, wherein:

[0026] Figure 1 A synchronous rotation control system for a mobile robot according to one embodiment of the present invention is shown;

[0027] Figure 2 A schematic top view of a mobile robot according to one embodiment is shown;

[0028] Figure 3 A schematic side view of a mobile robot according to one embodiment is shown;

[0029] Figure 4 The mounting location of an inertial measurement unit on a mobile robot is illustrated in one embodiment.

[0030] Figure 5 A schematic model of a wheeled odometer module according to one embodiment is shown; and

[0031] Figure 6 A schematic diagram of a PID control algorithm for a controller according to one embodiment is shown. Detailed Implementation

[0032] To make the above and other features and advantages of the present invention clearer, the invention will be further described below with reference to the accompanying drawings. It should be understood that the specific examples given herein are for the purpose of explanation to those skilled in the art and are exemplary only, not restrictive.

[0033] In all the views of the accompanying drawings, corresponding reference numerals indicate corresponding parts. Those skilled in the art will understand that the elements in the drawings are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements in the drawings may be exaggerated relative to other elements to aid in understanding the various embodiments of the invention. Furthermore, common but easily understood elements that are useful or necessary in commercially viable embodiments are generally not depicted to facilitate viewing of these embodiments of the invention less obstructively.

[0034] For ease of description, this document may use spatial relative terms such as “below”, “above”, “left”, and “right” to describe the relationship between one element or feature as illustrated in the accompanying drawings and another element or feature.

[0035] Exemplary embodiments of the invention will now be described more fully with reference to the accompanying drawings.

[0036] Figure 1A synchronous rotation control system 100 for a mobile robot according to one embodiment of the present invention is shown. For example, the mobile robot may include a chassis and a rotatable tray, and may be a differential wheel mobile robot.

[0037] like Figure 1 As shown, the synchronous rotation control system 100 may include at least a controller 101, an inertial measurement unit 102, a wheel odometer module 105, and a pallet synchronous rotation actuator 106. Figure 1 As shown, the controller 101 is communicatively connected to the inertial measurement unit 102, the wheel odometer module 105, and the pallet synchronous rotation actuator 106. The wheel odometer module 105 includes a first speed sensor 103 and a second speed sensor 104. The above connections can be wired or wireless.

[0038] The inertial measurement unit 102 is configured to measure in real time the chassis of the mobile robot about a vertical axis perpendicular to the ground (as described below). Figure 4 The vertical axis Z shown is rotated at a first angular velocity W1 and the first angular velocity W1 is sent to the controller 101.

[0039] The first speed sensor 103 and the second speed sensor 104 are configured to measure, in real time, the first speed V1 of the first differential wheel (e.g., the left differential wheel) and the second speed V2 of the second differential wheel (e.g., the right differential wheel) of the chassis of the mobile robot.

[0040] The wheeled odometer module 105 is configured to calculate, in real time, the second angular velocity W2 of the mobile robot's chassis rotating about the vertical axis Z based on the first velocity V1 and the second velocity V2, and send the second angular velocity W2 to the controller 101.

[0041] The controller 101 is configured to communicate with the inertial measurement unit 102, the wheel odometer module 105, and the pallet synchronous rotation actuator 106 to control the pallet synchronous rotation actuator 106 based at least on the first angular velocity W1 and the second angular velocity W2 of the chassis, such that when the chassis of the mobile robot rotates by an angle in a rotation direction, the pallet synchronous rotation actuator 106 controls the rotatable pallet of the mobile robot to rotate synchronously by the same angle in the opposite direction of the rotation direction.

[0042] A mobile robot employing the synchronous rotation control system 100 according to this embodiment of the invention can achieve the following: when the chassis of the mobile robot rotates, the rotatable pallet rotates in the opposite direction relative to the chassis in real time by the same angle, so as to achieve the effect that the chassis of the mobile robot rotates, but the rotatable pallet remains stationary relative to the ground. Thus, when transporting goods in relatively narrow workspaces (e.g., aisles) such as T-shaped or L-shaped spaces, the chassis of the mobile robot employing the synchronous rotation control system 100 according to this embodiment of the invention can turn flexibly without causing the pallet and the goods on it to rotate, thereby particularly ensuring the stability of the goods when turning.

[0043] Figure 1 The diagram also shows a pallet angle sensor 108 included in the chassis drive 107 and synchronous rotation control system 100 of the mobile robot. The chassis drive 107 is mounted to the chassis of the mobile robot, and the pallet angle sensor 108 is mounted on the mobile robot. The chassis drive 107 and the pallet angle sensor 108 can also be communicatively connected to a controller 101. The controller 101 can also be configured to control the chassis drive 107 and receive the pallet angle measured by the pallet angle sensor 108. The pallet angle sensor 108 is described in more detail below.

[0044] Figure 2 A schematic top view of a mobile robot according to one embodiment is shown. The mobile robot is generally indicated by reference numeral 200. The mobile robot 200 has a rotatable tray 201 and a chassis 204, the chassis 204 being equipped with a first differential wheel 202 and a second differential wheel 203. It should be understood that the mobile robot 200 described herein may include other wheels and other components not shown, known to those skilled in the art. The first differential wheel 202 and the second differential wheel 203 may be driven by a chassis drive 107.

[0045] Figure 3 A schematic side view of a mobile robot according to one embodiment is shown. Figure 3 Also shown is a tray synchronous rotation actuator 106, which is coupled between the rotatable tray 201 and the chassis 204 of the mobile robot 200, and is configured to be controlled by the controller 101 such that when the chassis 204 of the mobile robot rotates by an angle in a rotation direction, the rotatable tray 201 of the mobile robot is controlled to rotate synchronously by the same angle in the opposite direction of the rotation direction.

[0046] There are two main methods for calculating the rotation angle of a mobile robot's chassis: 1) rotation angle calculation based on an inertial measurement unit (IMU) and 2) rotation angle calculation based on a wheeled odometer module. This invention aims to fuse these two calculation methods to improve the accuracy of chassis rotation angle calculation.

[0047] The following is for reference. Figure 4 Describe the process of calculating the chassis rotation angle based on the inertial measurement unit.

[0048] Figure 4 The mounting location of the inertial measurement unit 102 on the mobile robot 200 in one embodiment is schematically shown. For clarity, Figure 4 The rotatable tray of the mobile robot is not shown. By way of illustration and not limitation, the inertial measurement unit 102 is a 6-axis sensor and is mounted on the upper surface of the chassis 204 of the mobile robot 200. Figure 4 The diagram also shows a longitudinal axis X, a transverse axis Y, and a vertical axis Z, wherein the longitudinal axis X is oriented in the direction of the robot's front and is perpendicular to the transverse axis Y, and the plane containing the longitudinal axis X and the transverse axis Y is parallel to the ground, while the vertical axis Z is perpendicular to the ground. The inertial measurement unit 102 is capable of measuring in real time the angular velocity (referred to herein as the first angular velocity W1) of the chassis 204 of the mobile robot 200 rotating about the vertical axis Z, and transmitting the first angular velocity W1 to the controller 101 in real time. The controller 101 integrates the received first angular velocity W1 over time to obtain the angle α of the chassis rotation of the mobile robot during the time period t.

[0049] The following is for reference. Figure 5 Describe the process of calculating the chassis rotation angle based on the wheel odometer module.

[0050] Figure 5 This is a schematic model of a wheeled odometer module based on one implementation scheme. For example... Figure 5 In the diagram, V represents the speed of the mobile robot; V1 represents the speed of the left differential wheel (i.e., the first differential wheel), i.e., the first speed; V2 represents the speed of the right differential wheel (i.e., the second differential wheel), i.e., the second speed; W2 represents the rotational angular velocity of the mobile robot's chassis calculated by the wheel odometer module (which is also referred to as the second angular velocity in this document); R represents the rotation radius of the chassis; D represents the distance between the left and right differential wheels of the mobile robot; d represents half of the distance D; and L represents the distance from the right differential wheel of the mobile robot to the center of a circle with a rotation radius of R.

[0051] Through derivation, the second angular velocity W2 of the chassis calculated by the wheel odometer module can be expressed by the following equation:

[0052]

[0053] The wheeled odometer module transmits the second angular velocity W2 to the controller in real time. The controller integrates the received second angular velocity W2 over time to obtain the angle β of the chassis rotation of the mobile robot during the time period t.

[0054] Inertial measurement units (IMUs) accumulate errors over long periods of operation, but the angles accumulated over a short period are relatively accurate. Wheeled odometer modules may calculate inaccurate angles due to differential wheel slippage on the mobile robot (e.g., on wet surfaces). Therefore, using either of these two methods (1) or (2) alone to calculate the chassis rotation angle of the mobile robot will introduce deviations and affect the robot's control accuracy during long-term operation.

[0055] To improve the control accuracy of mobile robots and reduce deviations caused by long-term operation, the synchronous rotation control system 100 of the present invention integrates the two methods mentioned above for calculating the rotation angle of the mobile robot's chassis in order to calculate the rotation angle of the mobile robot's chassis more accurately. The specific method of the above integration is described in detail below.

[0056] Under normal circumstances, when the differential wheel of the mobile robot does not slip, the absolute value of the difference between the first angular velocity W1 and the second angular velocity W2, |W1-W2|, is less than or equal to a threshold (the threshold is any value between 0 and 0.5 rad / s, such as 0, 0.1, 0.2, 0.3, 0.4, or 0.5 rad / s). In this case, the angle of rotation of the mobile robot's chassis is based on the angle β calculated from the angular velocity W2 calculated by the wheel odometer module. Once |W1-W2| is greater than the threshold, the differential wheel is considered to be slipping. In this case, the angle of rotation of the mobile robot's chassis is based on the angle α calculated from the angular velocity W1 measured by the inertial measurement unit.

[0057] Therefore, in one implementation, the controller is further configured as follows:

[0058] When |W1–W2| is less than or equal to a threshold, the second angular velocity W2 is taken as the actual angular velocity of the mobile robot's chassis, and the angle of rotation of the mobile robot's chassis at the current moment relative to the previous moment is obtained by integrating the second angular velocity W2 over the time interval between the current moment and the previous moment; or

[0059] When |W1–W2| is greater than a threshold, the first angular velocity W1 is taken as the actual angular velocity of the chassis of the mobile robot, and the first angular velocity W1 is integrated over time in the time interval between the current moment and the previous moment to obtain the angle of rotation of the chassis of the mobile robot at the current moment relative to the previous moment.

[0060] Alternatively, in an alternative implementation, a calibration operation is required when |W1–W2| is greater than a threshold, i.e., when the differential wheel of the mobile robot slips.

[0061] Specifically, in this alternative implementation, the controller is further configured to:

[0062] When |W1–W2| is less than or equal to a threshold, the second angular velocity W2 is taken as the actual angular velocity of the mobile robot's chassis, and the angle of rotation of the mobile robot's chassis at the current moment relative to the previous moment is obtained by integrating the second angular velocity W2 over the time interval between the current moment and the previous moment; or

[0063] When |W1–W2| is greater than a threshold, the actual angle of the mobile robot's chassis at the current moment is β0+(α1-α0), where β0 is the rotation angle of the chassis at the previous moment calculated by the angular velocity calculated by the wheel odometer module, α0 is the rotation angle of the chassis at the previous moment calculated by the angular velocity measured by the inertial measurement unit, and α1 is the rotation angle of the chassis at the current moment calculated by the angular velocity measured by the inertial measurement unit, and α1 can be updated in real time.

[0064] To facilitate understanding, a specific example is provided below to explain this alternative implementation scheme.

[0065] Under normal circumstances, assuming the angular velocity measured by the inertial measurement unit (IMU) and the angular velocity calculated by the wheel odometry unit are both 0.3 rad / s, this indicates that the differential wheel of the mobile robot is not slipping. In this case, the rotation angle of the mobile robot's chassis can be calculated using the angular velocity calculated by the wheel odometry module. However, if at the current time t1, the angular velocity calculated by the wheel odometry module is 0.3 rad / s, while the angular velocity measured by the IMU is 0 rad / s or less than 0.3 rad / s, this indicates that the differential wheel of the mobile robot is slipping (idling).

[0066] Assume that the chassis rotation angle at the previous time t0, calculated from the angular velocity of the wheel odometer module, is β0, and the chassis rotation angle at the previous time t0, calculated from the angular velocity measured by the inertial measurement unit (IMU), is α0. The chassis rotation angle at the current time t1, calculated from the angular velocity of the wheel odometer module, is β1, and the chassis rotation angle at the current time t1, calculated from the angular velocity measured by the IMU, is α1. When the differential wheel of the mobile robot slips, β0 + (α1 - α0) can be taken as the actual angle of the mobile robot's chassis at the current time, where α1 can be updated in real time to the chassis rotation angle α2 at the next time t2, calculated from the angular velocity measured by the IMU.

[0067] For example, suppose that at the next time t2, the angular velocity measured by the inertial measurement unit (IMU) still deviates significantly from the angular velocity calculated by the wheel odometer module, and the rotation angle of the chassis at the next time t2 calculated based on the angular velocity measured by the IMU is α2, then β0 + (α2 - α0) is taken as the actual rotation angle of the robot's chassis at the next time t2. If at the next time t3, the angular velocity measured by the IMU and the angular velocity calculated by the wheel odometer module have a small deviation or are the same, then it is assumed that the differential wheels of the robot are not slipping. The rotation angle of the robot's chassis can be calculated based on the angular velocity W2 calculated by the wheel odometer module, but β0 + (α2 - α0) needs to be added. This represents the actual rotation angle of the robot's chassis at the next moment t3. Here, T represents the integration time.

[0068] In one implementation, controller 101 is further configured to:

[0069] Based on the angle of rotation of the mobile robot's chassis at the current moment relative to the previous moment, the rotatable tray of the mobile robot is controlled by the tray synchronous rotation actuator to rotate in the opposite direction by the same angle.

[0070] In this implementation, the controller issues a control quantity for the relative angle each time.

[0071] In one implementation, controller 101 is further configured to:

[0072] Based on the angle of rotation of the mobile robot's chassis at the current moment relative to the previous moment, the angle of rotation of the mobile robot's chassis at the current moment relative to the initial moment is calculated, and according to the angle of rotation of the chassis at the current moment relative to the initial moment, the rotatable tray of the mobile robot is controlled to rotate in the opposite direction by the same angle through the tray synchronous rotation actuator.

[0073] In this implementation, the controller issues a control quantity of absolute angle each time.

[0074] In one embodiment, the synchronous rotation control system 100 further includes a tray angle sensor 108, which is mounted on the mobile robot 200 and configured to be communicatively connected to the controller 101, to measure the rotation angle γ of the rotatable tray 201 of the mobile robot 200, and to transmit the rotation angle γ to the controller 101.

[0075] In one embodiment, the controller 101 is further configured to use a PID control algorithm to control the tray synchronous rotation actuator, wherein the rotation angle γ is used in the PID control algorithm.

[0076] Figure 6 A schematic diagram of a PID control algorithm for a controller according to one embodiment is shown.

[0077] Specifically, to more accurately control the angular velocity of the rotatable tray to achieve a preset rotation angle, a PID control algorithm can be used. The following are the calculation formulas for the relevant PID control algorithm:

[0078]

[0079] Wherein, Kp represents the proportional coefficient of the controller; Ti represents the integral coefficient of the controller; Td represents the derivative coefficient of the controller, and the proportional coefficient, integral coefficient and derivative coefficient can be adjusted according to actual conditions; u(t) represents the output of the PID control algorithm (corresponding to the angular velocity of the rotatable tray in this paper); t represents time; and e(t) represents the deviation between the target angle and the actual angle of the rotatable tray.

[0080] For synchronous control, for example, before activating the synchronous rotation mode, assuming the initial angle of the mobile robot's chassis is A0 and the initial angle of the rotatable tray is γ0, and after activating the synchronous rotation mode, the real-time angle of the mobile robot's chassis is A and the real-time angle of the rotatable tray is γ, then the rotation angle of the mobile robot's chassis is ΔA = A - A0, and the target angle that the rotatable tray needs to achieve (the angle after rotating in the opposite direction by the same angle relative to the initial position of the rotatable tray) is γ1 = γ0 - ΔA. Then the deviation between the target angle and the real-time angle of the rotatable tray is e(t) = γ1 - γ; e(t) is processed by proportional, integral, and derivative operations (i.e., by the PID control algorithm) to obtain the output u(t) (i.e., the angular velocity of the rotatable tray), and the calculation process is shown in formula (1). u(t) is provided to the tray synchronous rotation actuator 106, that is, instructing the tray synchronous rotation actuator to rotate at an angular velocity u(t). As long as there is a deviation between the real-time angle γ of the rotatable pallet and the target angle γ1, the controller will control the pallet synchronous rotation actuator and then control the rotatable pallet to rotate, ultimately achieving the effect of the rotatable pallet remaining stationary relative to the ground.

[0081] It should be understood that the specific features, operations and details described above in this document regarding the synchronous rotation control system of the present invention can also be similarly applied to the synchronous rotation control method of the present invention, or vice versa.

[0082] It should be understood that the various modules / units of the synchronous rotation control system of the present invention can be implemented entirely or partially through software, hardware, firmware, or a combination thereof. Each module / unit can be embedded in the processor of a computer device in hardware or firmware form, or it can be stored in the memory of a computer device in software form for the processor to call and execute the operation of the module / unit. Each module / unit can be implemented as an independent component or module, or two or more modules / units can be implemented as a single component or module.

[0083] In one embodiment, a computer device is provided, including a memory and a processor. The memory stores computer instructions that, when executed by the processor, cause the execution of steps of the method for synchronous rotation control of a mobile robot according to the present invention. The computer device can be broadly categorized as a server, terminal, or any other electronic device with the necessary computing and / or processing capabilities. In one embodiment, the computer device may include a processor, memory, network interface, communication interface, etc., connected via a system bus. The processor of the computer device can be used to provide the necessary computing, processing, and / or control capabilities. The memory of the computer device may include a non-volatile storage medium and internal memory. The non-volatile storage medium may store an operating system, computer programs, etc. The internal memory can provide an environment for the operation of the operating system and computer programs in the non-volatile storage medium. The network interface and communication interface of the computer device can be used to connect and communicate with external devices via a network. When the computer program is executed by the processor, it performs the steps of the method for program execution according to the present invention.

[0084] This invention can be implemented as a computer-readable storage medium storing computer instructions that, when executed by a processor, cause the execution of steps of the method for synchronous rotation control of a mobile robot according to this invention. In one embodiment, the computer instructions are distributed across a plurality of network-coupled computer devices or processors, such that the computer instructions are stored, accessed, and executed in a distributed manner by one or more computer devices or processors. A single method step / operation, or two or more method steps / operations, may be executed by a single computer device or processor or by two or more computer devices or processors. One or more method steps / operations may be executed by one or more computer devices or processors, and one or more other method steps / operations may be executed by one or more other computer devices or processors. One or more computer devices or processors may execute a single method step / operation, or execute two or more method steps / operations.

[0085] Those skilled in the art will understand that all or part of the steps of this invention for program execution can be instructed by computer instructions to related hardware, such as computer devices or processors, to perform these computer instructions. These computer instructions may be stored in a non-transitory computer-readable storage medium, and when executed, they cause the steps of this invention for program execution to be performed. Depending on the context, any references herein to memory, storage, databases, or other media may include non-volatile and / or volatile memory. Examples of non-volatile memory include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), flash memory, magnetic tape, floppy disk, magneto-optical data storage device, optical data storage device, hard disk, solid-state drive, etc. Examples of volatile memory include random access memory (RAM), external cache memory, etc.

[0086] The technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification, provided that such combination does not contain contradictions.

[0087] Although the invention has been described in conjunction with embodiments, those skilled in the art will understand that the above description and drawings are exemplary and not restrictive, and the invention is not limited to the disclosed embodiments. Various modifications and variations are possible without departing from the spirit of the invention.

Claims

1. A synchronous rotation control system for a mobile robot, the mobile robot having a chassis and a rotatable tray, the chassis being equipped with a first differential wheel and a second differential wheel, the synchronous rotation control system comprising a controller, an inertial measurement unit, a wheel-type odometer module, and a tray synchronous rotation actuator; wherein, The inertial measurement unit is configured to measure in real time the first angular velocity W1 of the chassis of the mobile robot rotating about a vertical axis perpendicular to the ground and send the first angular velocity W1 to the controller; The wheeled odometer module includes a first speed sensor and a second speed sensor. The first speed sensor and the second speed sensor are configured to measure the first speed V1 of the first differential wheel and the second speed V2 of the second differential wheel of the mobile robot chassis in real time, respectively. The wheeled odometer module is configured to calculate the second angular velocity W2 of the mobile robot chassis rotating about the vertical axis in real time based on the first speed V1 and the second speed V2, and send the second angular velocity W2 to the controller. as well as The controller is configured to communicatively connect to the inertial measurement unit, the wheel odometer module, and the pallet synchronous rotation actuator to control the pallet synchronous rotation actuator based at least on the first angular velocity W1 and the second angular velocity W2 of the chassis, such that when the chassis of the mobile robot rotates by an angle along a rotation direction, the pallet synchronous rotation actuator controls the rotatable pallet of the mobile robot to synchronously rotate by the same angle in the opposite direction of the rotation direction.

2. The synchronous rotation control system according to claim 1, wherein, The controller is further configured to: When |W1–W2| is less than or equal to a threshold, the second angular velocity W2 is taken as the actual angular velocity of the chassis of the mobile robot, and the angle of rotation of the chassis of the mobile robot at the current moment relative to the previous moment is obtained by integrating the second angular velocity W2 with respect to time over the time interval between the current moment and the previous moment. or When |W1–W2| is greater than a threshold, the first angular velocity W1 is taken as the actual angular velocity of the chassis of the mobile robot, and the first angular velocity W1 is integrated over time in the time interval between the current moment and the previous moment to obtain the angle of rotation of the chassis of the mobile robot at the current moment relative to the previous moment.

3. The synchronous rotation control system according to claim 1, wherein, The controller is further configured to: When |W1–W2| is less than or equal to a threshold, the second angular velocity W2 is taken as the actual angular velocity of the chassis of the mobile robot, and the angle of rotation of the chassis of the mobile robot at the current moment relative to the previous moment is obtained by integrating the second angular velocity W2 with respect to time over the time interval between the current moment and the previous moment. or When |W1–W2| is greater than a threshold, the actual angle of the mobile robot's chassis at the current moment is β0+(α1-α0), where β0 is the previous moment's rotation angle of the chassis calculated based on the second angular velocity W2 calculated by the wheel odometer module, α0 is the previous moment's rotation angle of the chassis calculated based on the first angular velocity W1 measured by the inertial measurement unit, and α1 is the current moment's rotation angle of the chassis calculated based on the first angular velocity W1 measured by the inertial measurement unit, and α1 can be updated in real time.

4. The synchronous rotation control system according to claim 2 or 3, wherein, The controller is further configured to: Based on the angle of rotation of the mobile robot's chassis at the current moment relative to the previous moment, the rotatable tray of the mobile robot is controlled to rotate in the opposite direction by the same angle through the tray synchronous rotation actuator; or Based on the angle of rotation of the mobile robot's chassis at the current moment relative to the previous moment, the angle of rotation of the mobile robot's chassis at the current moment relative to the initial moment is calculated, and according to the angle of rotation of the chassis at the current moment relative to the initial moment, the rotatable tray of the mobile robot is controlled to rotate in the opposite direction by the same angle through the tray synchronous rotation actuator.

5. The synchronous rotation control system according to any one of claims 1-3, wherein, The synchronous rotation control system also includes a tray angle sensor, which is mounted on the mobile robot and configured to communicate with the controller to measure the rotation angle γ of the rotatable tray of the mobile robot and transmit the rotation angle γ to the controller.

6. The synchronous rotation control system according to claim 5, wherein, The controller is further configured to use a PID control algorithm to control the tray synchronous rotation actuator, wherein the rotation angle γ is used in the PID control algorithm.

7. A mobile robot, comprising: Synchronous rotation control system according to any one of claims 1-6; Chassis; A first differential wheel and a second differential wheel are mounted on the chassis; A rotatable tray, which is connected to the chassis via a tray synchronous rotation actuator and configured to be driven to rotate by the tray synchronous rotation actuator; as well as A chassis drive, which is mounted to the chassis and configured to drive the first differential wheel and the second differential wheel.

8. A method for synchronous rotation control of a mobile robot, wherein the mobile robot includes a synchronous rotation control system, a chassis, and a rotatable tray, the chassis being equipped with a first differential wheel and a second differential wheel, the synchronous rotation control system including a controller, an inertial measurement unit, a wheel odometer module, and a tray synchronous rotation actuator, the method comprising: The inertial measurement unit measures in real time the first angular velocity W1 of the mobile robot's chassis rotating about a vertical axis perpendicular to the ground; The second angular velocity W2 of the mobile robot's chassis rotating around the vertical axis is calculated in real time based on the first speed V1 of the first differential wheel and the second speed V2 of the second differential wheel measured in real time by the first speed sensor and the second speed sensor of the wheel odometer module, respectively. as well as The controller controls the pallet synchronous rotation actuator based at least on the first angular velocity W1 and the second angular velocity W2, such that when the chassis of the mobile robot rotates by an angle along a rotation direction, the pallet synchronous rotation actuator controls the rotatable pallet to synchronously rotate by the same angle in the opposite direction of the rotation direction.

9. The method according to claim 8, wherein, The method further includes: When |W1–W2| is less than or equal to a threshold, the second angular velocity W2 is taken as the actual angular velocity of the mobile robot's chassis, and the angle of rotation of the mobile robot's chassis at the current moment relative to the previous moment is obtained by integrating the second angular velocity W2 over the time interval between the current moment and the previous moment; or When |W1–W2| is greater than a threshold, the first angular velocity W1 is taken as the actual angular velocity of the chassis of the mobile robot, and the first angular velocity W1 is integrated over time in the time interval between the current moment and the previous moment to obtain the angle of rotation of the chassis of the mobile robot at the current moment relative to the previous moment.

10. The method according to claim 8, wherein, The method further includes: When |W1–W2| is less than or equal to a threshold, the second angular velocity W2 is taken as the actual angular velocity of the mobile robot's chassis, and the angle of rotation of the mobile robot's chassis at the current moment relative to the previous moment is obtained by integrating the second angular velocity W2 over the time interval between the current moment and the previous moment; or When |W1–W2| is greater than a threshold, the actual angle of the mobile robot's chassis at the current moment is β0+(α1-α0), where β0 is the previous moment's rotation angle of the chassis calculated based on the second angular velocity W2 calculated by the wheel odometer module, α0 is the previous moment's rotation angle of the chassis calculated based on the first angular velocity W1 measured by the inertial measurement unit, and α1 is the current moment's rotation angle of the chassis calculated based on the first angular velocity W1 measured by the inertial measurement unit, and α1 can be updated in real time.

11. The method according to claim 9 or 10, wherein, The method further includes: The controller controls the pallet synchronous rotation actuator to rotate synchronously in opposite directions by the same angle based on the angle of rotation of the mobile robot at the current moment relative to that at the previous moment; or The controller calculates the angle of rotation of the mobile robot at the current moment relative to the initial moment based on the angle of rotation of the mobile robot at the current moment relative to the previous moment, and controls the pallet synchronous rotation actuator to rotate synchronously in the opposite direction by the same angle.

12. The method according to any one of claims 8-10, wherein, The method further includes measuring the rotation angle γ of the rotatable tray of the mobile robot using a tray angle sensor mounted on the mobile robot and configured to communicate with the controller.

13. The method according to claim 12, wherein, The controller is further configured to use a PID control algorithm to control the tray synchronous rotation actuator, wherein the rotation angle γ is used in the PID control algorithm.

14. A computer device comprising a memory and a processor, the memory storing computer instructions that, when executed by the processor, cause a method for synchronous rotation control of a mobile robot according to any one of claims 8 to 13 to be performed.

15. A non-transitory computer-readable storage medium having stored thereon computer instructions that, when executed by a processor, cause the method for synchronous rotation control of a mobile robot according to any one of claims 8 to 13 to be performed.

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