1. A servo system for a robot end, comprising an end servo module coupleable to the robot end and an end servo controller communicably coupled with the end servo module, wherein:

the tail end servo module comprises a first laser sensor, a communication module, a servo motor and a mechanical linkage mechanism of the servo motor, the tail end of the mechanical linkage mechanism is connected with a process tool for processing, and the tail end servo module sends data collected by the first laser sensor to the tail end servo controller through the communication module and receives a control signal for the servo motor from the tail end servo controller;

the servo controller calculates track compensation parameters according to the data collected by the first laser sensor, and generates control signals for the servo motor according to the track compensation parameters so as to indicate the servo motor to reach a specified position.

2. The system of claim 1, wherein the first laser sensor is positioned on a side of the end servo module that is coupled to a process tool and is capable of capturing an image of a front of travel of the robot end.

3. The system of claim 1, wherein the servo controller detects a process trace point to be processed from data collected by the first laser sensor.

4. The system of claim 3, wherein the servo controller further comprises a memory unit for saving process trace points detected via the first laser sensor and for saving calibration trace points for a predetermined robot end-tool center point.

5. The system of claim 4, wherein the end servo controller determines a trajectory compensation parameter by comparing a process trajectory point detected during a process performed by the robot with the calibration trajectory point, and generates a control signal to the servo motor based on the trajectory compensation parameter.

6. The system of claim 4 or 5, wherein the end servo controller predetermines the nominal trajectory point of the robot end tool center point by:

before starting a technological processing process, starting the robot to execute a processing program corresponding to a teaching path of the robot for a plurality of times;

in each running process, the running track of the tail end servo module is tracked and measured in real time, and the running track is represented by position data of a series of track points and corresponding time sequences;

and fitting the measured multiple running tracks into a calibration running track of the tail end servo module, and simultaneously converting each track point on the calibration running track into a calibration track point of the center point of the corresponding robot tail end tool.

7. The system of claim 6, wherein the real-time tracking of the trajectory of the measurement end servo module is performed by a laser tracker disposed in an external environment.

8. The system of claim 2, wherein the end servo module further comprises a second laser sensor disposed opposite the first laser sensor on a side of the end servo module to which the process tool is coupled.

9. A control method for a servo system according to any preceding claim, comprising:

in the robot processing engineering, a first laser sensor arranged on a tail end servo module is used for acquiring an image in front of the tail end of the robot in real time and sending the image to a tail end servo controller which is communicably coupled with the tail end servo module;

detecting a process track point to be processed by the tail end servo controller based on an image acquired by the first laser sensor;

the tail end servo controller compares the detected process track point with a predetermined calibration track point of the center point of the tail end tool of the robot to determine a track compensation parameter, and generates a control signal for a servo motor in the tail end servo module according to the track compensation parameter;

and instructing, by the end servo module, the servo motor to reach a specified position based on a control signal from the end servo controller.

10. The method of claim 9, further comprising predetermining a nominal trajectory point for the center point of the robot end tool by:

before starting a technological processing process, starting the robot to execute a processing program corresponding to a teaching path of the robot for a plurality of times;

in each running process, the running track of the tail end servo module is tracked and measured in real time, and the running track is represented by position data of a series of track points;

and fitting the measured multiple running tracks into a calibration running track of the tail end servo module, and simultaneously converting each track point on the calibration running track into a calibration track point of the center point of the corresponding robot tail end tool.

11. A computer-readable storage medium, characterized in that a computer program is stored on the computer-readable storage medium, which program, when executed, carries out the method of any one of claims 9-10.

Background

Industrial robots are multi-joint manipulators or multi-degree-of-freedom machine devices oriented to the industrial field, and can make a robot end effector move along a given track at a certain speed and posture to complete a certain movement through linkage servo control and cooperation of each joint or degree of freedom. Depending on the requirements of the application, different end effectors may be mounted on the robot end joint, for example, process tools such as a welding gun, a gripper, a suction cup, a nozzle, etc. The process tool moves to another pose along a given track by linkage servo control of each joint of the robot, so that the corresponding process machining or manufacturing process is completed. In the manufacturing, machining and assembling processes in the high-precision manufacturing field, the machining precision of a product is very important, and high requirements are put on the absolute positioning precision and the path precision of the tail end of the robot. At present, the repeated positioning precision of an industrial robot is high, but the absolute positioning precision is low, which is limited by the mechanical structure of the robot and the servo precision of each joint. Particularly, in the high-end application field of high precision and high speed, it is difficult to realize accurate trajectory tracking and control for the robot end effector.

Disclosure of Invention

Therefore, an object of the embodiments of the present invention is to provide a servo system installed at a robot end and a control method thereof, which can independently or auxiliarily control a running track of an actuator at the robot end accurately, so as to meet the requirements of the robot in high-speed and high-precision industrial applications.

The above purpose is realized by the following technical scheme:

according to a first aspect of embodiments of the present invention, there is provided a servo system for a robot end, comprising an end servo module coupleable to the robot end and an end servo controller communicably coupled with the end servo module, wherein: the tail end servo module comprises a first laser sensor, a communication module, a servo motor and a mechanical linkage mechanism of the servo motor, the tail end of the mechanical linkage mechanism is connected with a process tool for processing, and the tail end servo module sends data collected by the first laser sensor to the tail end servo controller through the communication module and receives a control signal for the servo motor from the tail end servo controller; the servo controller calculates track compensation parameters according to the data collected by the first laser sensor, and generates control signals for the servo motor according to the track compensation parameters so as to indicate the servo motor to reach a specified position.

In some embodiments of the invention, the first laser sensor may be positioned on the side of the end servo module that is coupled to the process tool and may capture an image of the front of the robot end travel.

In some embodiments of the present invention, the servo controller may detect a process trace point to be processed according to data collected by the first laser sensor.

In some embodiments of the invention, the servo controller may further comprise a memory unit for saving the process trace points detected via the first laser sensor and for saving the calibration trace points for a predetermined robot end-tool center point.

In some embodiments of the present invention, the end servo controller may determine a trajectory compensation parameter by comparing a process trajectory point detected during a process of the robot with the calibration trajectory point, and generate a control signal for the servo motor according to the trajectory compensation parameter.

In some embodiments of the present invention, the end servo controller may predetermine the nominal trajectory point of the robot end tool center point with the end servo in the null position by: before starting a technological processing process, starting the robot to execute a processing program corresponding to a teaching path of the robot for a plurality of times; in each running process, the running track of the tail end servo module is tracked and measured in real time, and the running track is represented by position data of a series of track points and corresponding time sequences; and fitting the measured multiple running tracks into a calibration running track of the tail end servo module, and simultaneously converting each track point on the calibration running track into a calibration track point of the center point of the corresponding robot tail end tool.

In some embodiments of the present invention, the real-time tracking of the operation trajectory of the measuring end servo module may be performed by a laser tracker disposed in an external environment.

In some embodiments of the present invention, the end servo module may further comprise a second laser sensor disposed opposite the first laser sensor on a side of the end servo module coupled to the process tool.

According to a second aspect of embodiments of the present invention, there is provided a control method for the servo system according to the first aspect of embodiments of the present invention, in a robot machining project, an image before a tip of a robot travels is collected in real time by a first laser sensor installed at a tip servo module and is sent to a tip servo controller communicably coupled with the tip servo module; detecting a process track point to be processed by the tail end servo controller based on an image acquired by the first laser sensor; the tail end servo controller compares the detected process track point with a predetermined calibration track point of the center point of the tail end tool of the robot to determine a track compensation parameter, and generates a control signal for a servo motor in the tail end servo module according to the track compensation parameter; and instructing, by the end servo module, the servo motor to reach a specified position based on a control signal from the end servo controller.

In some embodiments of the present invention, the method may further include pre-determining a calibration trajectory point of the robot end tool center point by: before starting a technological processing process, starting the robot to execute a processing program corresponding to a teaching path of the robot for a plurality of times; in each running process, the running track of the tail end servo module is tracked and measured in real time, and the running track is represented by position data of a series of track points; and fitting the measured multiple running tracks into a calibration running track of the tail end servo module, and simultaneously converting each track point on the calibration running track into a calibration track point of the center point of the corresponding robot tail end tool. In the above process, the end servo is in null.

According to a third aspect of embodiments of the present invention, there is provided a computer readable storage medium having stored thereon a computer program which, when executed, implements the method as described in the second aspect of the embodiments above.

The servo system and the control method for the robot tail end provided by the embodiment of the invention integrate sensing control, servo control and track planning, and can accurately track and correct the position of the robot tail end actuator in real time, so that the running track precision of the robot tail end actuator is effectively improved, and the requirements of high-speed application or/and high-precision application, such as 3D printing, laser welding, spraying, gluing, high-precision compound motion (such as small circle cutting) and the like, can be met.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.

Drawings

Embodiments of the invention are further described below with reference to the accompanying drawings, in which:

fig. 1 shows a schematic configuration of a servo system for a robot tip according to an embodiment of the present invention.

FIG. 2 shows a simplified schematic diagram of an external side view of an end servo module according to one embodiment of the present invention.

Fig. 3 shows a working scenario intent of a servo system for a robot tip according to an embodiment of the present invention.

Fig. 4 shows a schematic diagram of a coordinate system involved in a servo system according to an embodiment of the invention.

FIG. 5 shows a flow diagram of the online operation of a servo system according to one embodiment of the invention.

FIG. 6 shows a schematic diagram of a tracking of a servo system according to an embodiment of the invention.

FIG. 7 is a diagram illustrating a hardware architecture of an end servo controller according to one embodiment of the invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail by embodiments with reference to the accompanying drawings. It is to be understood that the embodiments described are only a few embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to provide a thorough understanding of embodiments of the invention. One skilled in the relevant art will recognize, however, that the invention may be practiced without one or more of the specific details, or with other methods, components, devices, steps, and so forth. In other instances, well-known methods, devices, implementations or operations have not been shown or described in detail to avoid obscuring aspects of the invention.

The block diagrams shown in the figures are functional entities only and do not necessarily correspond to physically separate entities. I.e. these functional entities may be implemented in the form of software, or in one or more hardware modules or integrated circuits, or in different networks and/or processor means and/or microcontroller means.

The flow charts shown in the drawings are merely illustrative and do not necessarily include all of the contents and operations/steps, nor do they necessarily have to be performed in the order described. For example, some operations/steps may be decomposed, and some operations/steps may be combined or partially combined, so that the actual execution sequence may be changed according to the actual situation.

In high-end application fields with high precision and high speed, the tail end of the robot is often in a high-speed motion state, and the inertia of the tail end of the robot is large, so that accurate real-time trajectory tracking and control of the tail end effector of the robot are difficult. In an embodiment of the present invention, a servo system installed at a robot end and a control method thereof are provided, which independently or in an auxiliary manner precisely control a running track of a robot end actuator by performing track compensation on a robot end TCP (Tool Center Point) to meet the requirements of high-speed or/and high-precision industrial applications. Fig. 1 shows a schematic structural diagram of a servo system for a robot tip according to an embodiment of the present invention. The robot end servo system generally includes an end servo module and an end servo controller communicatively coupled to the end servo module. The end servo module can be arranged on the end joint of the robot and can also be arranged on any tool. The end servo module may include a laser sensor, a communication module, and a servo motor and mechanical linkage thereof. The tail end of the mechanical linkage mechanism of the servo motor can be connected with a process tool required for carrying out corresponding process machining. The end servo module sends data collected by the laser sensor to the end servo controller through the communication module and receives control signals of the servo motor from the end servo controller. The servo motor can move correspondingly according to the received control signal so as to move the connected process tool to a specified position at a specified speed. When the robot is used for carrying out process machining, the laser sensor in the tail end servo module is mainly used for detecting the actual process track to be machined in advance, so that the tail end TCP of the robot can accurately track the process track. Therefore, the laser sensor, also called a front sensor, is arranged in front of the end servo module, and collects front images along the running direction of the robot end, so as to detect a plurality of process track points to be traveled based on the collected images. In yet another embodiment, another laser sensor may be mounted on the end servo module, similar to the pre-sensor, on the side of the end servo module that is connected to the process tool and positioned opposite the pre-sensor (thus, also referred to as the post-sensor). Therefore, when the tail end of the robot moves back and forth, one of the front sensor and the rear sensor is used for acquiring a front image of the tail end of the robot in the running direction so as to detect a process track point to be processed in advance. That is, any of the two laser sensors mounted on the end servo module can be used as a pre-sensor depending on the direction of movement of the robot end. When one of the laser sensors is used as a front sensor, the other is correspondingly a rear sensor, and the rear sensor can correspondingly capture an image behind the tail end of the robot, so that the acquired image can be used for quality detection of the process. FIG. 2 shows a schematic diagram of an example end servo module appearance. As shown in fig. 2, the front and rear laser sensors are integrated with the end servo module, mounted on the side of the end servo module where the process tool is coupled. Each laser sensor has its own base coordinate: pre-sensor base coordinates 1 and post-sensor base coordinates 2. The front distance 5 of the laser focusing point 3 of the front laser sensor relative to the robot tail end TCP and the rear distance 6 of the laser focusing point 4 of the rear laser sensor relative to the TCP can be set through the tail end servo controller according to the requirements of practical application, and the focusing depth and the scanning range of the laser sensor can be adjusted, so that the process track 7 is in the range. The front distance and the rear distance may be set or adjusted according to the requirements of the actual processing environment or the processing program, and are not particularly limited herein. And the laser sensor transmits each frame of image acquired through laser imaging to the tail end servo controller for processing. The image acquisition can have two modes: single sample or continuous sample. Different sampling frequencies can also be set in the continuous sampling mode.

With continued reference to fig. 1, the end servo controller may calculate a trajectory compensation parameter from data collected by the laser sensor in the end servo module and generate a control signal to the servo motor based on the trajectory compensation parameter. As shown in fig. 1, the end servo controller mainly includes three functional modules: sensing control, trajectory management and servo control. The sensing control module can acquire the process track points to be processed according to the data acquired by the laser sensor in real time. The track management module can calculate the track compensation parameters by comparing the real-time detected process track points with the pre-acquired calibration track points. The servo control module generates control signals for the servo motors according to the track compensation parameters from the track management module to instruct the servo motors to execute corresponding motions to drive corresponding control objects. Thus, the process tool connected to the servo motor can move along a certain posture to another posture at a designated speed, thereby executing the corresponding process or manufacturing process. In some embodiments, the end servo controller may further include a storage unit for storing relevant data and results involved in the sensing control, trajectory management, and servo control processes. The servo system with independent sensors and controllers mounted at the end of the robot can provide real-time and accurate track control, thereby greatly improving the precision of the process machining. And the end servo system is independent of the control system of the robot, can be suitable for various robots and is also suitable for fixed or movable (on a track or a conveying belt) tools.

Referring now to FIG. 3, a work scenario illustration of a servo system for a robot tip is shown, according to one embodiment of the present invention. The end servo module 2 in the servo system is arranged on the end joint of the robot 1 through a flange 3. The process tool 5 is coupled to a mechanical linkage 4 operated by the end servo module 2. The end-servo controller (not shown) of the servo system is communicatively coupled to the end-servo module 2, which may be fixed in some way, for example, to the side of the robot end joint or to a robot arm at a short distance from the end-servo module 2. The table 8 has a given machining path 9. During the initialization phase, a teaching path of the robot can be obtained during the robot teaching process by performing simple robot teaching along the process track 9. Then, before starting the machining process, the robot is started to execute a process machining program corresponding to the teaching path for a plurality of times, during which the motion track (position and posture) of the end servo module 2 can be tracked and measured in real time by using the laser tracker 7 arranged in the scene, and further the calibration track of the center point of the end tool of the robot is determined based on the running track of the end servo module. In this way, when the robot starts the actual machining process, an image of the front of the robot tip in the travel is acquired in real time by a laser sensor (not shown) integrated in the tip servo module 2 itself. The tail end servo controller detects a process track to be processed based on an image acquired by the laser sensor, compares the detected process track with a calibration track of a central point of a tail end tool of the robot, which is acquired in advance, to obtain a corresponding compensation parameter, and generates a control signal based on the obtained compensation parameter so as to control a servo motor to perform real-time track compensation on a TCP (transmission control protocol) at the tail end of the robot to meet the requirement of high-precision processing. Therefore, even if the position of the process part is deviated in the machining process, the tail end servo system can enable the robot tail end TCP to accurately track the actual process track.

Also shown in fig. 3 are the coordinate systems associated with the components in the scenario, such as robot base coordinates 10, end servo base coordinates 11, TCP coordinates 12, table base coordinates 13, and laser tracker base coordinates 14. Wherein the laser tracker 7 can be used for measuring the movement track of the robot end in the initial stage as mentioned above, and can also be used for measuring the position of each coordinate system (such as an end servo module, a process tool, a robot, etc.) and the parameters related to each other between each coordinate system, for example, at the time of system initialization. The laser tracker generally includes a laser head, a tracking mirror system, and a laser tracking controller. The laser tracker can accurately measure (or track-measure) the position and attitude of an object by means of a mirror mounted on the object. A conversion can be made between the coordinate positions measured in the above-mentioned coordinate systems. Fig. 4 shows a schematic diagram of the respective coordinate systems and their relationships involved in the above scenario. Wherein o is₁The table coordinate system is represented, which may be, for example, geodetic coordinates, with respect to which the geometric position of the machined part is taken. The laser tracker coordinate system is denoted as o₆Relative to the table coordinate system o₁Is stationary. End servo module coordinate system o₂Is a dynamic coordinate system which changes along with the movement of the robot and can be obtained by the measurement of a laser tracker. For example, a laser tracker mirror may be attached to the tip servo module in an initialization stage, so that the motion trajectory of the robot tip may be measured in real time by the laser tracker. o₃Coordinate system representing the robot's end TCP at the end servo zero position, o₄Coordinate system representing the front sensor, o₅Coordinate system representing rear sensor, since front sensor and rear sensor are integrated with end servo moduleTogether, therefore o₄And o₅Relative to the servo module coordinate system o₂Is stationary.

Calibration of the coordinate system is usually required at initialization of the servo system. The calibration of the coordinate systems is to determine the associated parameters between the coordinate systems, and can be usually expressed by a homogeneous transformation matrix. Since there are many general methods for calibrating the transformation matrix between coordinate systems, these processes are not repeated here. In the examples of the present application, A₁Represents o₆Conversion to o₁Of the transformation matrix, A₂Represents o₃Conversion to o₂Of the transformation matrix, A₃Represents o₄Conversion to o₂Of the transformation matrix, A₄Represents o₅Conversion to o₂The transformation matrix of (2). Each coordinate is hereinafter transformed to a geodetic coordinate representation by the transformation matrix described above. E.g. o₂The coordinate system is measured by the laser tracker with respect to o₆Of a coordinate system, can be represented by A₁Transformation to the geodetic coordinate system o₁Shown below. Also for example, wherein the measurements of the front and rear laser sensors are respectively the coordinate system o of the relative sensor₄，o₅Said, but each pass through A₃And A₄The measurement result can be transferred to o₂The coordinate system is then transformed to a coordinate system o relative to the earth₁. Accordingly, also can pass through A₂Will TCP coordinate system o₃Conversion to o₂The coordinate system is then relative to the geodetic coordinate system o₁. A herein₂Is calculated from the geometry of the process tool.

When the operation flow of the end servo system according to the embodiment of the present invention is described below, all the mentioned variables, constants, and coordinates related to each component have been transformed into the same coordinate system, for example, transformed into geodetic coordinates, for convenience of description. The operation process of the end servo system is divided into two stages: an offline operating phase and an online operating phase. The off-line operation stage does not require the actual process, while the on-line operation stage actually performs the actual process.

The end servo system according to some embodiments of the present invention is installed at an end joint of a robot, operates independently of a control system of the robot itself, can communicate with a laser tracker, a robot controller, and the like, performs various coordinate calibrations of the system itself, and can store path teaching related data acquired or acquired by itself in a robot teaching process in a storage unit of the end servo controller. For example, in the robot teaching process, the end servo controller may save the acquired robot teaching path in its storage unit.

And in the off-line operation stage of the tail end servo system, starting the robot to execute the machining program corresponding to the robot teaching path for a plurality of times, and running under the same condition every time. In each operation process, the operation track of the end servo module can be tracked and measured in real time through a laser tracker arranged in an external environment. Thus, each run results in a set of position data for the end servo module measured by the laser tracker. By comparing the tested multiple sets of position data, the maximum path error of the robot executing the teaching path can be calculated. The error represents the accuracy of the repetitive operation of the robot. The precision of the repetitive operation of the robot is usually high. If the repeat running accuracy thus obtained can meet the requirements of the process, such multiple sets of test data are fit to the calibration path or calibration trajectory of the end servo module. Such a nominal path is represented in the form of a series of positions of the tracing points. Hereinafter, the location of the kth trace point on the calibration path of the end servo module may beWhere k is a natural number. For the position of the end servo module on the calibration pathThe position of the corresponding robot end TCP (noted as "TCP") can also be calculated from the dimensions or other component characteristics of the process tool itself to which the end servo module is coupled) And therefore, a calibration track of the TCP at the tail end of the robot is obtained. In the off-line operation stage, the tail end servo system obtains the calibration track of the tail end servo module corresponding to each process track to be processed, and calculates the corresponding calibration track of the tail end TCP of the robot, namely a series of track point dataStored in a memory unit of the end servo controller for use in a subsequent trajectory compensation process (described in more detail below). In the track compensation process of the online operation stage, which will be described later, the calibration track of the tail end servo module and/or the calibration track of the tail end TCP of the robot, which are fitted in the offline operation stage, may be used as a comparison factor for real-time tracking and track compensation, so that the real-time dynamic track tracking precision of the tail end of the robot may be improved to the precision of the repeated track running of the robot, and further, the requirements of many high-speed applications or/and high-precision applications, such as 3D printing, laser welding, spraying, gluing, high-precision compound motion (such as small circle cutting), and the like, may be satisfied.

And after the calibration track of the tail end servo module and/or the tail end TCP of the robot corresponding to each to-be-processed process track is obtained in the off-line operation stage, the on-line operation stage can be started. FIG. 5 is a flow chart illustrating an on-line operation phase of the end servo system according to one embodiment of the present invention. The robot program is started first, and then a target, which is the starting point of a process track to be processed, is captured by a front sensor of an end servo module. The lead laser sensor continuously and continuously retrieves the machining start point of a specific part according to the geometric characteristic parameters of the start point. Once the starting target is found, the end servo controller enters a tracking mode in order to get the robot end TCP exactly to the starting point. When the TCP reaches the process starting point, a process processing program can be started, and during the process, the tail end servo controller continuously tracks and detects the process track so as to control the TCP at the tail end of the robot to accurately track the actual process track until the process ending point is reached. And a preposed laser sensor positioned on the tail end servo module continuously detects the process track point and judges whether the process track point is a termination track point. The process is terminated when TCP reaches a termination point and other related processes are stopped, such as turning off the sensor and stopping the tracking mode. And when the robot runs to the termination position, terminating the running program of the robot.

When the robot does not find the starting target, the robot runs according to the teaching path, and the tail end servo module is at a zero position. In the actual processing process, due to the uncertainty of the placement position of the workpiece, the path of the actual process track to be processed and the starting point and the ending point of the track are obtained by real-time detection of a front laser sensor integrated on the end servo module. When the front sensor detects the initial point of the process track, the tail end servo controller enters a real-time tracking mode to accurately compensate the TCP running track of the tail end of the robot in real time, so that the robot can accurately track the corresponding process track. The process of the end servo system accurately performing the track following according to an embodiment of the present invention will be described with reference to fig. 6. As shown in fig. 6, indicated by solid dots is a calibration trajectory of the robot tip TCP obtained at the off-line stage, which has been stored in the storage unit of the tip servo controller; while another trace, represented by a hollow dot, represents the process trace detected in real time by the pre-sensor on the end servo module. For the purpose of describing the tracking process, the laser tracker and the front laser sensor are set to have the same sampling frequency, and the control step size of the servo system is set to be consistent with the sampling step size of the sensor, but it should be understood that this is for convenience of explanation only and is not intended to be limiting. The process of tracking by the end servo system can be roughly divided into four stages:

■ first stage: the tail end servo module does not find the initial point of the process track, the robot runs according to the teaching path, and the tail end servo module is at the zero position.

■ second stage: when TCP arrivesFront-end transmission of end servo moduleThe sensor finds the starting point of the process trajectoryAssuming the front sensor is opposite toCorresponds to m sample points. By passingThe corresponding calibration track point can be found from the storage unit of the end servo controllerFrom which the path error can be calculatedPath error (Delta T) based on single step using m-step linear compensation method_n+m/m) generating a control signal (also called a control quantity) to be sent to the servo motor of the end servo module, so that the robot runs to the starting point of the process trackWhen it is in position

■ third stage: at this stage, the process has begun. Assuming that the current sampling time sequence point is k, and the current TCP position is T_kThe control quantity applied to the end servo module is DeltaT_k(ii) a The position of the process track point detected in real time by the current sensor is set asAnd the previous sensor detection valueThe TCP is stored in a storage unit, and the TCP can be accurately tracked to the next process track through the following stepsPoint:

1) finding the next calibration track point from the storage unit

2) Finding the process track points of the next step from the storage unit

3) Determining the path error of the next step

4) Finding the next control increment d Delta T_k+1＝ΔT_k+1-ΔT_k；

5) Controlling the end servo module to apply the required control increment d Δ T at a given step size (distance)_k+1；

6) Until the TCP reaches the next process trace point,

7) and (5) repeating the steps (1-7) until the TCP reaches the end point of the process track by letting k be k + 1.

■ fourth stage: at the moment, the technological process is finished, the robot runs according to the calibration track, and the tail end servo module is in the final control position.

In the above-described embodiments of the present invention, the end servo controller is a computing device independent of the robot controller, the process controller, the PLC controller, and the like. Different from the existing industrial robot with high repeated positioning precision and low absolute positioning precision, the terminal servo controller can control the terminal servo module arranged at the terminal joint of the robot, so that the absolute positioning precision of the terminal of the robot can be improved to the level of the repeated positioning precision of the robot, namely the real-time dynamic track tracking precision of the robot is improved to the precision of the repeated track running of the robot, and the requirements of high-speed or/and high-precision application are met. Furthermore, since the end servo system is independent of the control system of the robot, it is applicable to any kind of robot, as well as to fixed or moving tooling (on rails or conveyor belts).

FIG. 7 is a diagram illustrating a hardware architecture of an end servo controller according to one embodiment of the invention. The end servo controller adopts a structure that a plurality of processors share a memory, wherein a processor-I is mainly responsible for program control, process control, track planning and a real-time path compensation algorithm. The processor-II is mainly responsible for the control of the laser sensor and the image processing. processor-III is primarily responsible for end servo control. Each processor has its own memory and can access the shared memory unit directly. The processors exchange data with each other through the shared memory unit. Each processor interacts with external devices such as end servo modules, laser sensors, laser trackers, robot controllers, process controllers, PLC controllers, notebook computers, etc. through a shared input/output interface. The end servo controller is an independent control device and is arranged near the end joint of the robot to shorten the length of a data transmission line of the three-dimensional laser sensor. The tail end servo controller integrates track management, sensing control and servo control, can synchronously process a large amount of sensor information under a high sampling frequency state and controls tail end servo in real time, and therefore real-time and accurate track tracking in a high-speed running process is met. It should be understood that the above hardware architecture is only exemplary and not limiting, and other computing devices may be used as the end servo controller. In some embodiments, the end servo controller may communicate with an external computing device, such as a laptop computer, by wired or wireless means. The initial calibration of the system is carried out through the notebook computer, and the system can be used as a state display device in the production process, and the state of each system can be selectively observed.

In another embodiment of the present invention, a computer-readable storage medium is further provided, on which a computer program or executable instructions are stored, and when the computer program or the executable instructions are executed, the technical solution as described in the foregoing embodiments is implemented, and the implementation principle thereof is similar, and is not described herein again. In embodiments of the present invention, the computer readable storage medium may be any tangible medium that can store data and that can be read by a computing device. Examples of computer readable storage media include hard disk drives, Network Attached Storage (NAS), read-only memory, random-access memory, CD-ROMs, CD-R, CD-RWs, magnetic tapes, and other optical or non-optical data storage devices. The computer readable storage medium may also include computer readable media distributed over a network coupled computer system so that computer programs or instructions may be stored and executed in a distributed fashion.

In another embodiment of the present invention, an electronic device is further provided, which includes a processor and a memory, where the memory is used for storing executable instructions that can be executed by the processor, and the processor is configured to execute the executable instructions stored in the memory, and when the executable instructions are executed, the technical solution described in any one of the foregoing embodiments is implemented, and the implementation principles thereof are similar, and are not described herein again.

Reference in the specification to "various embodiments," "some embodiments," "one embodiment," or "an embodiment," etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in various embodiments," "in some embodiments," "in one embodiment," or "in an embodiment," or the like, in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Thus, a particular feature, structure, or characteristic illustrated or described in connection with one embodiment may be combined, in whole or in part, with a feature, structure, or characteristic of one or more other embodiments without limitation, as long as the combination is not logical or operational.

The terms "comprises," "comprising," and "having," and similar referents in this specification, are intended to cover non-exclusive inclusions, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements but may alternatively include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus. The word "a" or "an" does not exclude a plurality. Additionally, the various elements of the drawings of the present application are merely schematic illustrations and are not drawn to scale.

Although the present invention has been described by the above embodiments, the present invention is not limited to the embodiments described herein, and various changes and modifications may be made without departing from the scope of the present invention.