Human-robot collaborative compliant assembly system of large components of heavy-duty industrial robot, and control method therefor

Abstract

Disclosed in the present invention are a human-robot collaborative compliant assembly system of large components of a heavy-duty industrial robot, and a control method therefor, which aim to solve the problems of the low absolute positioning accuracy of industrial robots and uncertain assembly positions and environments and to meet the requirements for high- accuracy assembly of large complex structural components. The system comprises an AGV, a control cabinet, a robot body, robot bearing connecting columns, a robot end connecting flange, an end assembly execution member, an assembly component, a component assembly fixing member and an operator. The control method comprises: establishing a coordinate system relationship between a robot body and an end assembly execution member, building a compensation calculation model and an admittance control model, analyzing admittance control, performing control algorithm calculation by means of monitoring the pose of a component in real time, monitoring changes in an external contact force, torque and a robot's end acceleration and angular acceleration, and performing pose correction on a robot. The present invention achieves high-accuracy assembly of a heavy-duty industrial robot and performs human-robot collaborative and automated compliant assembly on customized components, thereby improving the assembly efficiency.

Description

Heavy-load industrial robot large component human-robot collaborative compliant assembly system and control method thereof TECHNICAL FIELD

[0001] The present application relates to the technical field of heavy-load industrial robot assembly, and discloses a heavy-load industrial robot large component human-robot collaborative compliant assembly system and a control method thereof. BACKGROUND

[0002] With the continuous development of manufacturing industry, industrial robots play an increasingly important role in the production process. Among them, heavy-load industrial robots are widely used in the fields of automobile manufacturing, aerospace, etc., and undertake key assembly, transportation and other tasks.

[0003] However, when such industrial robots face complex components, it is often difficult to achieve accurate fitting and stable assembly. First, complex workpieces themselves have certain deformation and deviation, which brings difficulties to the accurate positioning and fitting of robots. Traditional robot end effectors usually adopt rigid structure and cannot effectively adapt to the ups and downs of the workpiece surface, which easily leads to loose fitting and even causes damage to the components. Secondly, the structure of heavy-load industrial robots is complex, and there is a certain error accumulation in the transmission of each joint, which also affects the accuracy of the final assembly. Finally, in the existing assembly process, the assembly position of the component to be assembled changes according to the actual situation, and a certain flexible guidance is needed to complete the preliminary positioning.

[0004] To solve the above problems, patent CN114454060A discloses a kind of unknown surface self-adaptive constant pressure tracking system and control method thereof, which installs one end of position self-adaptive actuator with industrial robot end, the other end is connected with machining tool and contacts with unknown surface to be tracked through machining tool, three-dimensional unknown surface self-adaptive constant pressure tracking is realized by adjusting the pose of industrial robot and one-dimensional force control of actuator. Although this method can realize constant pressure tracking, it is limited to small plane and small range tracking, and cannot achieve large range tracking, which has great limitations for some assembly positions.

[0005] Patent CN109910005A discloses a variable admittance control method and system for a robot, which enables human-robot interaction robots to quickly and sensitively respond to the intentions of operators through variable admittance compliant control method, and considers the assembly comfort of the assembler for human-robot low-speed and low-acceleration interaction. However, no relevant settings are made for the collision between the robot and the rigid assembly workpiece during the assembly process, especially for large curved surface heavy-load workpieces, and this method does not involve related situations.

[0006] In summary, using a flexible end effector, the adaptive elastic component can achieve passive adaptation to the workpiece surface, but this method is often difficult to accurately track and position in a large range, and it is difficult to meet the requirements of large component assembly. Through the admittance control algorithm for active compliance control, but the existing algorithm is mostly for small load interaction between human and robot, and there are still certain limitations for heavy industrial robot large component assembly. Therefore, for heavy industrial robot large component assembly in human-robot cooperation scene, a new control method is urgently needed. SUMMARY

[0007] To solve the problems existing in the prior art, the technical scheme provided by the application is as follows:

[0008] A heavy industrial robot large component human-robot cooperation compliant assembly system, comprising:

[0009] AGV car, control cabinet, robot body, robot bearing connecting column, robot end connecting flange, end assembly execution component, assembly component and component assembly fixing component;

[0010] The AGV car is used to receive external position moving instructions and move to a specified position point; the front end thereof is connected with the robot body through the robot bearing connecting column, and the rear end thereof is directly connected with the control cabinet;

[0011] The control cabinet and the robot body are in communication connection to control the robot body to correct the joint pose; the end of the robot body is connected with the end assembly execution component through the robot end connecting flange, and the robot body moves the end assembly execution component to a specified assembly pose point according to the control instruction of the control cabinet;

[0012] The end assembly execution component is connected with the assembly component through the suction cup assembly located on the lower side thereof; the component assembly fixing component is fixed at the specified assembly pose point, and the upper side thereof is a surface assembly to be assembled; when the end assembly execution component moves to the specified assembly pose point, the assembly component and the surface assembly to be assembled are matched.

[0013] Further, the end assembly execution component further comprises:

[0014] A force sensor, a force sensor connecting flange, an inertial sensor, an inertial sensor connecting disc and an execution component body; the execution component body is located in the middle of the end assembly execution component, a force sensor is installed on the upper side of the execution component body through the force sensor connecting flange, and an inertial sensor is installed on the side of the execution component body through the inertial sensor connecting disc; the suction cup assembly comprises five pairs of ten suction cups and is symmetrically installed on the lower sides of the execution component body.

[0015] Further, the component assembly fixing member comprises:

[0016] the to-be-assembled surface assembly, the rotating assembly, and the positioning support assembly;

[0017] the positioning support assembly comprises a frame support assembly for supporting and fixing the to-be-assembled surface assembly and the rotating assembly, four adjustable base support assemblies installed at four corners of the bottom of the frame support assembly, and four non-adjustable base support assemblies symmetrically distributed at the bottom of both sides of the frame support assembly;

[0018] the rotating assembly is movably installed at the upper end of both sides of the frame support assembly;

[0019] the to-be-assembled surface assembly comprises a to-be-assembled surface frame assembly and a to-be-assembled surface installed above the to-be-assembled surface frame assembly, one side of the to-be-assembled surface frame assembly is fixedly connected with the frame support assembly, and the other side is fixedly connected with the rotating assembly.

[0020] The application further provides a control method of the heavy-load industrial robot large-component human-machine collaborative compliant assembly system, and specifically comprises the following steps:

[0021] S1, receiving three-axis force and three-axis moment borne by a force sensor following component based on a force sensor, and performing gravity center parameter identification on the force sensor following component to obtain actual three-axis force and three-axis moment generated by external force on the force sensor following component, and performing real-time compensation on the force sensor following component; the force sensor following component comprises a force sensor connecting flange, an inertial sensor, an inertial sensor connecting disc, an execution component main body, a suction disc assembly, and an assembly component;

[0022] S2, receiving three-axis acceleration and three-axis angular velocity of an end assembly execution component at a specified assembly pose point based on an inertial sensor, and performing zero drift parameter identification on the inertial sensor to obtain actual three-axis acceleration and three-axis angular velocity, and performing real-time compensation on the inertial sensor;

[0023] S3, real-time monitoring actual three-axis force, three-axis moment, three-axis acceleration and three-axis angular velocity after compensation, feedback through a control algorithm, and continuously correcting a current robot body end pose until an assembly component and a to-be-assembled surface complete an expected surface fitting effect.

[0024] Further, step S1 specifically comprises:

[0025] S11, constructing a world coordinate system O w -X w Y w Z w , and a robot body coordinate system O r -X r Y rZ r , robot end flange coordinate system O f -X f Y f Z f , and the force sensor coordinate system is O s -X s Y s Z s ; the Z w axis of the world coordinate system is parallel to and opposite to the direction of gravity, and the attitude conversion matrix of the force sensor coordinate system relative to the world coordinate system is constructed The formula is expressed as:

[0026] Wherein, is the attitude conversion matrix of the robot body coordinate system relative to the world coordinate system; is the attitude conversion matrix of the robot end flange coordinate system relative to the robot body coordinate system; is the attitude conversion matrix of the force sensor coordinate system relative to the robot end flange coordinate system;

[0027] S12, determine the position point of the component assembly fixing member, the robot body moves around the position point, and stops at six position points, and obtain the coordinates of the robot body in the Cartesian coordinate system at the six position points: (X, Y, Z, A, B, C), wherein X, Y and Z are the positions of the robot in the Cartesian coordinate system; A, B and C are the poses of the robot in the Cartesian coordinate system; the three-axis force and three-axis moment received by the force sensor after filtering are obtained through the inertial sensor in real time and after Kalman filtering;

[0028] S13, according to the coordinate system transformation relationship in step S11 and the three-axis force and three-axis moment obtained in step S12, the gravity G and the gravity center (G x , G y , G z ) of the component below the force sensor, the roll angle φ and the pitch angle w of the robot body base, and the zero drift value (F x , F y , F z , M x , M y , M z ) of the force sensor are calculated through the gravity center compensation algorithm;

[0029] Wherein, G x , G y , G z are the X, Y and Z components of the gravity center of the component below the force sensor in the Cartesian coordinate system; F x , F y, F z is the zero-drift three-axis force of the force sensor below the component; x , M y , M z is the zero-drift three-axis torque of the force sensor below the component;

[0030] S14, according to the parameters calculated in step S13, combined with the coordinates of the robot body in the Cartesian coordinate system in real time, and the three-axis force and three-axis torque received by the force sensor after filtering under the corresponding coordinates, the actual three-axis force (f x , f y , f z ) and actual three-axis torque (t x , t y , t z ) generated by the external force on the component below the force sensor are calculated through the zero-drift removal algorithm.

[0031] Further, step S2 specifically comprises:

[0032] S21, a world coordinate system O w -X w Y w Z w , a robot body coordinate system O r -X r Y r Z r , a robot end flange coordinate system O f -X f Y f Z f and an inertial sensor coordinate system O g -X g Y g Z g , the Z w axis of the world coordinate system is parallel and opposite to the direction of gravity, and the attitude conversion matrix of the inertial sensor coordinate system relative to the world coordinate system is constructed The formula is expressed as:

[0033] wherein, is the attitude conversion matrix of the robot body coordinate system relative to the world coordinate system; is the attitude conversion matrix of the robot end flange coordinate system relative to the robot body coordinate system; is the attitude conversion matrix of the inertial sensor coordinate system relative to the robot end flange coordinate system;

[0034] S22, determine the position point of the component assembly fixing member, the robot body moves around the position point, and stops at six position points, real-time acquisition of the coordinates of the robot body in the Cartesian coordinate system: (X, Y, Z, A, B, C) at the six position points; through the inertial sensor, real-time receiving, and through Kalman filtering, obtaining the three-axis acceleration and three-axis angular velocity received by the filtered inertial sensor under the corresponding coordinates;

[0035] S23, based on the coordinate system conversion relationship constructed in step S21 and the three-axis acceleration and three-axis angular velocity obtained in step S22, the calibration coefficients (K x , K y , K z , K a , K b , K c ) and zero drift values (A x , A y , A z , W a , W b , W c ) of the inertial sensor are obtained through the inertial compensation algorithm; wherein, K x , K y , K z are the calibration coefficients of the three-axis acceleration received by the inertial sensor; K a , K b , K c are the calibration coefficients of the three-axis angular velocity received by the inertial sensor; A x , A y , A z are the zero drift values of the three-axis acceleration received by the inertial sensor; W a , W b , W c are the zero drift values of the three-axis angular velocity received by the inertial sensor;

[0036] S24, according to the calibration coefficients and zero drift values obtained in step S23, compensate the inertial sensor; combined with the coordinates of the robot body in the Cartesian coordinate system obtained in step S22, and the three-axis acceleration and three-axis angular velocity received by the filtered inertial sensor under the corresponding coordinates, through the zero drift removal algorithm, real-time calculation of the actual acceleration (a x , a y , a z ) and actual three-axis angular velocity (w a , w b , w c ) of the end assembly execution member, and further calculate the actual three-axis angular acceleration (a a , a b , a c ) of the end assembly execution member.

[0037] Further, step S3 specifically comprises:

[0038] S31, according to the actual three-axis force, three-axis moment, three-axis acceleration and three-axis angular velocity obtained in step S1 and step S2, a mobility control model is designed as a control algorithm of the assembly task, and the formula expression of the mobility control model when the robot body makes one-dimensional translational motion is:

[0039] Wherein, m is the virtual mass; b is the virtual damping; k is the virtual stiffness; is the robot body end acceleration; is the robot body end speed; x is the robot body end position; f is the actual force acting on the robot body end below the force sensor, that is, the actual force acting on the robot body end below the force sensor; is the robot body end desired acceleration; is the robot body end desired speed; x n is the robot body end desired position; f n is the robot body end desired force; a is the actual acceleration of the end assembly execution component, that is, the actual acceleration of the end assembly execution component; x n , f n is set to zero, and the assembly task direction and assembly speed are determined by calculating the difference between x and x n ;

[0040] S32, when adjusting the pose, in order to ensure the assembly effect and improve the assembly efficiency, reduce the motion stiffness and reduce the vibration amplitude when collision occurs; increase the motion stiffness, increase the position adjustment time and space when rebounding, that is, classify the parameter k, and the classification formula is as follows:

[0041] Wherein, k n is the effective virtual stiffness; λ1 is the virtual stiffness adjustment parameter 1; λ2 is the virtual stiffness adjustment parameter 2; ρ is the acceleration adjustment parameter;

[0042] S33, the mobility control model when one-dimensional rotational motion is designed, and the formula expression is:

[0043] Wherein, α is the virtual rotational inertia; β is the virtual rotational damping; ψ is the virtual rotational stiffness; is the robot body end angular acceleration; is the robot body end angular velocity; θ is the robot body end rotation angle; t is the actual moment acting on the robot body end below the force sensor, that is, the actual moment acting on the robot body end below the force sensor; is the robot body end desired angular acceleration; θ is the desired angular velocity of the robot body end; n t is the desired rotation angle of the robot body end; n a is the desired action torque of the robot body end; θ a is the actual angular acceleration of the end assembly execution member, that is, the robot body end; θ n , t n , and a n are set to zero, and the assembly task direction and assembly speed are determined by calculating the difference between θ and θ x , t y , and a z ;

[0044] S34, continuously adjust the pose and monitor in real time, when monitoring the coordinates (X, Y, Z, A, B, C) of the robot body in the Cartesian coordinate system within a certain Δt time, maintain within a certain error fluctuation range, and the actual three-axis force (f x , f y , f z ) and three-axis torque (t x , t y , t z ) calculated in real time maintain a fixed fluctuation range corresponding to the assembly pose, corresponding to the f z parameters, the remaining f x , f y , t x , t y , t z parameters fluctuate around zero; the actual acceleration (a x , a y , a z ) and actual angular acceleration (a a , a b , a c ) calculated in real time maintain a fluctuation range around zero, it is considered that the assembly task is completed.

[0045] Based on the above technical scheme, the present application has the following beneficial effects:

[0046] 1) The present application proposes a heavy-load industrial robot large component human-machine cooperation flexible assembly system. Through the AGV car combined with the heavy-load industrial robot system, the flexible planning of the assembly position is realized, and the assembly workspace can be greatly expanded. At the same time, thanks to the human-machine cooperation application of the heavy-load industrial robot, the system can realize human-machine cooperation flexible preliminary positioning and self-adaptive flexible assembly under high load. Combined with the flexible end assembly execution frame, flexible fixing and clamping of large components can be realized. Reduce product defects caused by assembly errors, collision and other factors, limit improve the efficiency, precision and consistency of assembly;

[0047] 2) The heavy-load industrial robot large component human-robot collaborative compliant assembly system proposed in the application adopts force sensors and inertial sensors to collect sensor data and robot pose in real time, can monitor the system working state in real time, reduces the safety risk in high-load and large component assembly operation through a feedback mechanism, and improves the safety of work;

[0048] 3) The control method of the heavy-load industrial robot large component human-robot collaborative compliant assembly system proposed in the application greatly shortens the assembly time of large components, improves the overall efficiency of the production line, and reduces the labor cost and time cost through the optimized admittance control algorithm and the efficient robot adaptive motion planning control algorithm. Especially for collision events, the algorithm is optimized, the rigidity of the assembly components before and after the collision is adjusted, the robot pose correction efficiency after each collision event is improved, and the equipment damage rate caused by the collision event is greatly reduced. BRIEF DESCRIPTION OF DRAWINGS

[0049] Fig. 1 is a system overall structure diagram of the application;

[0050] Fig. 2 is a structure schematic diagram of the end assembly execution member in the system proposed in the application;

[0051] Fig. 3 is a structure schematic diagram of the assembly fixed member in the system proposed in the application;

[0052] Fig. 4 is a control method flow schematic diagram proposed in the application. DETAILED DESCRIPTION

[0053] In order to make the purpose, technical scheme and advantages of the application clearer and more intelligible, the application will be described in detail below in conjunction with the drawings. It should be noted that these specific embodiments are only used to explain the application and do not limit its scope. In addition, the technical features involved in each embodiment described in the text can be combined with each other as long as they do not conflict with each other.

[0054] In describing the application, it should be particularly noted that unless otherwise explicitly specified or limited, when referring to a component "connected" to another component, it means that it can be directly connected or indirectly connected through an intermediate medium. Terms such as "mounted", "fixed, etc. should be broadly understood, for example, they can mean fixed connection, detachable connection or integral connection, and can be mechanical connection or electrical connection, direct connection or indirect connection through an intermediate, or even include the communication relationship or interaction between the two components. For those skilled in the art, these terms can be understood in the specific meaning in the application according to the specific circumstances.

[0055] Further, the steps in the present application are arranged with reference numerals, but are not used to limit the sequence of the steps, unless the sequence of the steps is explicitly stated or the execution of a certain step needs other steps as a basis, otherwise the relative sequence of the steps can be adjusted. It can be understood that the term "and / or" used herein relates to and covers any and all possible combinations of one or more of the associated listed items.

[0056] As shown in FIGS. 1-3, the present embodiment provides a heavy-load industrial robot large-component human-robot collaborative compliant assembly system, which specifically comprises, as shown in FIG. 1:

[0057] AGV trolley 1, control cabinet 2, robot body 3, robot bearing connecting column 4, robot end connecting flange plate 5, end assembly execution member 6, assembly component 7, component assembly fixing member 8 and operator 9.

[0058] The AGV trolley 1 is a large-motion-range high-bearing trolley, which is used to receive external position movement instructions and move to a specified position point; the front end thereof is connected with the robot body 3 through the robot bearing connecting column 4, and the rear end thereof is directly connected with the control cabinet 2;

[0059] The control cabinet 2 and the robot body 3 are a large-motion-range multi-degree-of-freedom heavy-load industrial robot system; the two are in communication connection, the control cabinet 2 is used to control the robot body 3 to correct the joint pose; the end of the robot body 3 is connected with the end assembly execution member 6 through the robot end connecting flange plate 5, and the robot body 3 moves the end assembly execution member 6 to a specified assembly pose point according to the control instructions of the control cabinet 2;

[0060] The end assembly execution member 6 adsorbs the assembly component 7 through the suction cup assembly 66 located at the lower side thereof; the component assembly fixing member 8 is fixed at the specified assembly pose point, and the upper side thereof is a to-be-assembled surface assembly 81; when the end assembly execution member 6 is guided to move to the specified assembly pose point by the human-robot collaboration of the operator 9, the assembly component 7 and the to-be-assembled surface assembly 81 realize component assembly.

[0061] The assembly component 7 is a different assembly object selected according to an assembly task, is adsorbed and fixed by the suction cup assembly 66 of the end assembly execution member 6, is guided by the human-robot collaboration of the operator 9 to move the robot body 3 to the assembly pose point, and is surface-adhered with the to-be-assembled surface 811 of the component assembly fixing member 8 to complete the specified assembly task.

[0062] More specifically, as shown in FIG. 2, the end assembly execution member 6 further comprises:

[0063] The force sensor 61, the force sensor connecting flange 62, the inertia sensor 63, the inertia sensor connecting disc 64, the execution member main body 65; the execution member main body 65 is located in the middle of the end assembly execution member 6, the force sensor 65 is installed above the force sensor connecting flange 62, and the inertia sensor 63 is installed on the side through the inertia sensor connecting disc 64; the suction cup assembly 66 includes five pairs of ten suction cups, which are symmetrically distributed and installed below the execution member main body 65.

[0064] In this embodiment, the force sensor 61 is a six-dimensional force sensor, which is connected with the robot body 3 through the robot end connecting flange 5, connected with the execution member main body 65 through the force sensor connecting flange 62, receives the three-axis force and three-axis torque of the components below the force sensor 61, and simultaneously performs real-time data transmission communication, transmits the data to the upper computer, and the upper computer performs control algorithm feedback.

[0065] The inertia sensor 63 is an acceleration and angular velocity sensor, which is connected with the execution member main body 65 through the inertia sensor connecting disc 64, installed at a specified position of the execution member main body 65, receives the three-axis acceleration and three-axis angular velocity of the end assembly execution member 6 at the specified position, and simultaneously performs real-time data transmission communication, transmits the data to the upper computer, and the upper computer performs control algorithm feedback.

[0066] The execution member main body 65 is a support and fixing structure of the end assembly execution member 6, which is connected with the force sensor 61 through the force sensor connecting flange 62 and connected with the inertia sensor 63 through the inertia sensor connecting disc 64, and mainly plays a role in supporting and fixing the end assembly execution member 6, wherein five pairs of suction cup assemblies 66 are arrayed and fixed on the execution member main body 65.

[0067] The suction cup assembly 66 is a vacuum suction cup assembly, five pairs of suction cup assemblies 66 are arrayed and fixed on the execution member main body 65, because the suction cup assembly 66 is a compliant suction cup and has five pairs of ten suction cups, it can adsorb corresponding large curved surface components, and the number and layout of the suction cups can be adjusted according to the assembly component 7 to complete the specified assembly task.

[0068] More specifically, as shown in FIG. 3, the component assembly fixing member 8 includes:

[0069] The component assembly fixing member 8 includes:

[0070] The positioning support assembly 83 comprises a frame support assembly 831 for supporting and fixing the surface assembly 81 to be assembled and the rotating assembly 82, four adjustable base support assemblies 832 installed at the bottom of the four corners of the frame support assembly 831, and four non-adjustable base support assemblies 833 symmetrically distributed at the bottom of the two sides of the frame support assembly 831; the surface assembly 81 to be assembled and the rotating assembly 82 are supported and fixed by the frame support assembly 831, and the assembly position is moved as needed to complete the specified assembly task.

[0071] The rotating assembly 82 is movably installed at the upper end of the two sides of the frame support assembly 831; and is used to adjust the angle of the surface assembly 81 to be assembled as needed.

[0072] The surface assembly to be assembled comprises a surface assembly frame assembly 812 and a surface 811 to be assembled installed above the surface assembly frame assembly 812; one side of the surface assembly frame assembly 812 is fixedly connected with the frame support assembly 831, and the other side is fixedly connected with the rotating assembly 82. The surface 811 to be assembled matched with the assembly part 7 is replaced as needed to adapt to different assembly requirements and complete the specified assembly task.

[0073] As shown in FIG. 4, the embodiment further provides a control method of the heavy-load industrial robot large-component human-robot collaborative compliant assembly system. The AGV trolley 1 carries the equipment and the assembly part 7 to move to the specified assembly position of the end assembly execution member 6. The force sensor 61 and the inertial sensor 63 perform real-time data transmission and communication, and transmit the data to the upper computer. The upper computer performs control algorithm feedback, and combines the human-robot collaborative guidance of the operator 9 and the adaptive assembly algorithm to control the movement of the robot body 3, drive the movement of the end assembly execution member 6 and the assembly part 7, that is, continuously adjust the pose, slowly approach the surface 811 to be assembled until the surface fitting process is completed. The control method specifically comprises the following steps:

[0074] S1, receiving three-axis force and three-axis torque of the components below the force sensor 61 based on the force sensor 61; and performing gravity center parameter identification on the components below the force sensor 61 to obtain actual three-axis force and three-axis torque generated by external force on the components below the force sensor 61; the components below the force sensor 61 comprise a force sensor connecting flange 62, an inertial sensor 63, an inertial sensor connecting disc 64, an execution member body 65, a suction cup assembly 66, and an assembly part 7;

[0075] As a preferred embodiment of step S1, S1 specifically comprises:

[0076] S11, constructing a world coordinate system O w -X w Y w Z w, the robot body 3 coordinate system is O r -X r Y r Z r , the robot end flange 5 coordinate system is O f -X f Y f Z f , and the force sensor 61 coordinate system is O s -X s Y s Z s ; the Z w axis of the world coordinate system is parallel to and opposite to the direction of gravity, and the attitude conversion matrix of the force sensor 61 coordinate system relative to the world coordinate system is constructed The formula is expressed as:

[0077] Wherein, is the attitude conversion matrix of the robot body 3 coordinate system relative to the world coordinate system; is the attitude conversion matrix of the robot end flange 5 coordinate system relative to the robot body 3 coordinate system; is the attitude conversion matrix of the force sensor 61 coordinate system relative to the robot end flange 5 coordinate system;

[0078] S12, determine the position point of the component assembly fixing member 8, and the robot body 3 moves around the position point and stops at six position points, and obtains the coordinates of the robot body 3 in the Cartesian coordinate system at the six position points: (X, Y, Z, A, B, C), wherein X, Y and Z are the positions of the robot in the Cartesian coordinate system; A, B and C are the poses of the robot in the Cartesian coordinate system; the three-axis force and three-axis moment received by the force sensor 61 corresponding to the coordinates are obtained by real-time receiving through the inertial sensor 63 and through Kalman filtering;

[0079] S13, according to the coordinate system transformation relationship in step S11 and the three-axis force and three-axis moment obtained in step S12, the gravity G and the gravity center (G x , G y , G z ) of the components below the force sensor 61, the roll angle φ and the pitch angle w of the robot body 3 base, and the zero drift values (F x , F y , F z , M x , M y , M z ) of the force sensor 61 are calculated through the gravity center compensation algorithm;

[0080] Wherein, G x , Gy , G z are X, Y, Z components of the gravity center of gravity of the components below force sensor 61 in the Cartesian coordinate system; F x , F y , F z are zero-drift three-axis forces of the components below force sensor 61; x , M y , M z are zero-drift three-axis moments of the components below force sensor 61;

[0081] In this embodiment, all the parameters calculated above will be used to calculate the actual force and moment generated by the external force on the components below force sensor 61;

[0082] S14, according to the parameters calculated in step S13, combined with the coordinates of the robot body 3 in the Cartesian coordinate system obtained in real time, and the three-axis force and three-axis moment received by the force sensor 61 after filtering at the corresponding coordinates, the actual three-axis force (f x , f y , f z ) and actual three-axis moment (t x , t y , t z ) generated by the external force on the components below force sensor 61 are calculated by zero-drift removal algorithm.

[0083] S2, based on the three-axis acceleration and three-axis angular velocity of the end assembly execution component 6 at the specified assembly pose point received by the inertial sensor 63; zero-drift parameter identification is performed on the inertial sensor 63, so as to compensate the inertial sensor 63 in real time, and obtain the actual three-axis acceleration and three-axis angular velocity;

[0084] As a preferred embodiment of step S2, S2 specifically includes:

[0085] S21, a world coordinate system O w -X w Y w Z w is constructed, and the coordinate system of the robot body 3 is O r -X r Y r Z r , the coordinate system of the robot end connecting flange 5 is O f -X f Y f Z f , and the coordinate system of the inertial sensor 63 is O g -X g Y g Z g , the Z wThe shaft is parallel to and opposite to the direction of gravity, and the attitude conversion matrix of the inertial sensor 63 coordinate system relative to the world coordinate system is constructed The formula is expressed as:

[0086] Wherein, is the attitude conversion matrix of the robot body 3 coordinate system relative to the world coordinate system; is the attitude conversion matrix of the robot end connecting flange 5 coordinate system relative to the robot body 3 coordinate system; is the attitude conversion matrix of the inertial sensor 63 coordinate system relative to the robot end connecting flange 5 coordinate system;

[0087] S22, determine the position point of the component assembly fixing member 8, the robot body 3 moves around the position point, and stops at six position points, and the coordinates of the robot body 3 in the Cartesian coordinate system at the six position points are obtained in real time: (X, Y, Z, A, B, C); The three-axis acceleration and three-axis angular velocity received by the inertial sensor 63 at the corresponding coordinates are received in real time and filtered through Kalman filtering;

[0088] S23, based on the coordinate system conversion relationship constructed in step S21 and the three-axis acceleration and three-axis angular velocity obtained in step S22, the calibration coefficients (K x , K y , K z , K a , K b , K c ) and zero drift values (A x , A y , A z , W a , W b , W c ) of the inertial sensor 63 are obtained through the inertial compensation algorithm; wherein, K x , K y , K z are the calibration coefficients of the three-axis acceleration received by the inertial sensor 63; K a , K b , K c are the calibration coefficients of the three-axis angular velocity received by the inertial sensor 63; A x , A y , A z are the zero drift values of the three-axis acceleration received by the inertial sensor 63; W a , W b , W c are the zero drift values of the three-axis angular velocity received by the inertial sensor 63;

[0089] In this embodiment, all the parameters calculated above will be used to calculate the actual acceleration and angular velocity of the end assembly execution member 6;

[0090] S24, compensate the inertial sensor 63 according to the calibration coefficient and zero drift value obtained in step S23; combine the coordinates of the robot body 3 in the Cartesian coordinate system obtained in real time in step S22, and the three-axis acceleration and three-axis angular velocity received by the filtered inertial sensor 63 under the corresponding coordinates, and calculate the actual acceleration (a x , a y , a z ) and actual three-axis angular velocity (w a , w b , w c ) of the end assembly execution member 6 in real time through the zero drift removal algorithm, and further calculate the actual three-axis angular acceleration (a a , a b , a c ) of the end assembly execution member 6.

[0091] S3, real-time monitor the actual three-axis force, three-axis torque, three-axis acceleration and three-axis angular velocity after compensation, and feedback through the man-machine cooperation guidance and adaptive control algorithm of the operator 9, and continuously correct the current end pose of the robot body 3 until the assembly part 7 and the to-be-assembled surface 811 complete the expected surface fitting assembly effect.

[0092] As a preferred embodiment of step S3, step S3 specifically includes:

[0093] S31, design a mobility control model as the control algorithm of the assembly task according to the actual three-axis force, three-axis torque, three-axis acceleration and three-axis angular velocity obtained in steps S1 and S2, and the formula expression of the mobility control model when the robot body 3 moves in one dimension is:

[0094] Wherein, m is the virtual mass; b is the virtual damping; k is the virtual stiffness; is the end acceleration of the robot body 3; is the end velocity of the robot body 3; x is the end position of the robot body 3; f is the actual acting force on the end of the robot body 3, is the end expected acceleration of the robot body 3; is the end expected velocity of the robot body 3; x n is the end expected position of the robot body 3; f n is the end expected acting force of the robot body 3; a is the actual acceleration of the end assembly execution member 6, that is, the end of the robot body 3; x n , fn set to zero value, f n set to zero value, the assembly process is more flexible and smooth, x n set to zero value, by calculating the difference between x and x n the direction and speed of the assembly task; the positive and negative of the difference reflects the direction, and the size of the difference reflects the speed;

[0095] In this embodiment, because the force sensor 61 and the following components are mounted on the end of the robot body 3, the force received is considered to be the same as the torque; in actual movement, the acceleration is relatively small, so the acceleration, angular velocity and angular acceleration of the end assembly execution component 6 are also considered to be the same as the end of the robot body 3.

[0096] In addition, in this embodiment, setting the parameters to zero value ensures that the desired acceleration, desired speed and desired force are all 0 during the human-robot collaborative guidance process, the veneering process and after the veneering is completed, which is not desired to produce unnecessary vibration at the end of the robot during the human-robot collaborative guidance process, the veneering process and after the veneering is completed, so as to make the human-robot collaborative guidance and veneering effect smooth and flexible, and the desired position can not be set to 0; in addition, the above parameters of the end of the robot body 3 are all formula convergence parameters, except that the actual acceleration of the end of the robot body 3 and the actual force of the end of the robot body 3 are the parameters obtained in steps S1 and S2;

[0097] S32, when adjusting the pose, in order to ensure the assembly effect and improve the assembly efficiency, reduce the motion rigidity and reduce the vibration amplitude when collision occurs; increase the motion rigidity, increase the position adjustment time and space when rebounding, that is, classify the parameters k, and the classification formula is as follows:

[0098] wherein, k n is the effective virtual stiffness; λ1 is the virtual stiffness adjustment parameter 1; λ2 is the virtual stiffness adjustment parameter 2; ρ is the acceleration adjustment parameter;

[0099] S33, a one-dimensional rotational motion admittance control model is designed, and the formula is expressed as:

[0100] wherein, α is the virtual rotational inertia; β is the virtual rotational damping; ψ is the virtual rotational stiffness; is the angular acceleration of the end of the robot body 3; is the angular velocity of the end of the robot body 3; θ is the rotational angle of the end of the robot body 3; t is the actual torque received by the force sensor 61 and the following components, that is, the end of the robot body 3; is the desired angular acceleration of the end of the robot body 3; is the desired angular velocity of the end of the robot body 3; θn is the desired rotation angle of the end of the robot body 3; t n is the desired force moment of the end of the robot body 3; a θ is the actual angular acceleration of the end of the robot body 3, that is, the end assembly execution member 6; θ n , t n is set to zero, and the assembly task direction and assembly speed are determined by calculating the difference between θ and θ n The positive and negative of the difference reflect the direction, and the size of the difference reflects the speed.

[0101] S34, continuously adjust the pose and monitor in real time. When it is monitored that the coordinates (X, Y, Z, A, B, C) of the robot body 3 in the Cartesian coordinate system are maintained within a certain error fluctuation range within a certain Δt time, and the actual three-axis forces (f x , f y , f z ) and three-axis force moments (t x , t y , t z ) calculated in real time are maintained within a fixed fluctuation range corresponding to the assembly pose, corresponding to the f z parameters, and the remaining f x , f y , t x , t y , t z parameters fluctuate around zero; the actual accelerations (a x , a y , a z ) and actual angular accelerations (a a , a b , a c ) calculated in real time are maintained within a fluctuation range around zero, it is considered that the assembly task is completed.

[0102] In summary, the heavy-load industrial robot large-component human-robot collaborative compliant assembly system and the control method thereof can solve the problem of low absolute positioning accuracy of the industrial robot, meet the assembly demand of large and complex structure components with high precision, and simultaneously consider human-robot collaboration and automatic compliant assembly for customized components, thereby improving the assembly efficiency.

[0103] In this specification, the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" and the like describe at least one embodiment or example described in connection with a specific feature, structure, material, or characteristic. These described specific features, structures, materials, or characteristics can be combined in an appropriate manner in one or more embodiments or examples. In addition, different embodiments or examples described in this specification and their features can be combined and combined by the skilled person without contradiction.

[0104] It will be apparent to those skilled in the art that the application is not limited to the details of the above-exemplified embodiments and that the present application can be implemented in other particular forms without departing from the spirit or essential characteristics of the present application. The embodiments should therefore be considered in all respects as illustrative and not restrictive, the scope of the application being indicated by the appended claims rather than by the above description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. No reference signs in the claims should be considered as limiting the scope of the claims with respect to the figures of the patent document.

Claims

1. A heavy duty industrial robot macro component human collaborative compliant assembly system characterized by, The application relates to an AGV (1), a control cabinet (2), a robot body (3), a robot bearing connecting column (4), a robot end connecting flange (5), an end assembly execution component (6), an assembly part (7) and a part assembly fixing component (8). The AGV (1) is used to receive external position moving instructions and moves to a specified position point. The upper front end of the AGV (1) is connected with the robot body (3) through the robot bearing connecting column (4), and the upper rear end is directly connected with the control cabinet (2). The control cabinet (2) is in communication connection with the robot body (3) and is used to control the robot body (3) to correct the joint pose; the end of the robot body (3) is connected with the end assembly execution component (6) through the robot end connecting flange (5), and the robot body (3) moves the end assembly execution component (6) to a specified assembly pose point according to the control instruction of the control cabinet (2). The end assembly execution component (6) is connected with the assembly part (7) through the suction cup assembly (66) located at the lower side of the end assembly execution component (6); the part assembly fixing component (8) is fixed at the specified assembly pose point and has a to-be-assembled surface assembly (81) at the upper side; when the end assembly execution component (6) moves to the specified assembly pose point, the assembly part (7) and the to-be-assembled surface assembly (81) realize curved surface fitting. The end assembly execution component (6) further comprises:

2. A heavy duty industrial robot large component human-robot collaborative compliant assembly system according to claim 1, wherein, a force sensor (61), a force sensor connecting flange (62), an inertial sensor (63), an inertial sensor connecting disc (64), an execution component main body (65) and a suction cup assembly (66); the execution component main body (65) is located at the middle part of the end assembly execution component (6), the force sensor (65) is installed on the execution component main body (65) through the force sensor connecting flange (62), and the inertial sensor (63) is installed on the side of the execution component main body (65) through the inertial sensor connecting disc (64); the suction cup assembly (66) comprises five pairs of ten suction cups and is symmetrically arranged on the two sides below the execution component main body (65). The part assembly fixing component (8) comprises:

3. A heavy duty industrial robot large component human-robot collaborative compliant assembly system as claimed in claim 1, wherein, a to-be-assembled surface assembly (81), a rotating assembly (82) and a positioning support assembly (83); the positioning support assembly (83) comprises a frame support assembly (831) used to support and fix the to-be-assembled surface assembly (81) and the rotating assembly (82), four adjustable base support assemblies (832) installed at the four corners of the bottom of the frame support assembly (831) and four non-adjustable base support assemblies (833) symmetrically arranged at the bottom of the two sides of the frame support assembly (831); the rotating assembly (82) is movably installed on the upper ends of the two sides of the frame support assembly (831); the to-be-assembled surface assembly comprises a to-be-assembled surface frame assembly (812) and a to-be-assembled surface (811) installed on the upper side of the to-be-assembled surface frame assembly (812); one side below the to-be-assembled surface frame assembly (812) is fixedly connected with the frame support assembly (831), and the other side is fixedly connected with the rotating assembly (82). The application further specifically comprises the following steps:

4. A control method of a heavy-duty industrial robot large component human-robot collaborative compliant assembly system, characterized by, ​ S1, receiving three-axis force and three-axis moment of the components below the force sensor (61) based on the force sensor (61); and performing gravity center parameter identification on the components below the force sensor (61) to obtain actual three-axis force and three-axis moment of the components below the force sensor (61) generated by external force after real-time compensation of the components below the force sensor (61); the components below the force sensor (61) include: a force sensor connecting flange (62), an inertial sensor (63), an inertial sensor connecting disc (64), an execution component main body (65), a suction cup assembly (66), and an assembly part (7); S2, receiving three-axis acceleration and three-axis angular velocity of the end assembly execution component (6) at a specified assembly pose point based on the inertial sensor (63); and performing zero drift parameter identification on the inertial sensor (63) to obtain actual three-axis acceleration and three-axis angular velocity after real-time compensation of the inertial sensor (63); S3, real-time monitoring of actual three-axis force, three-axis moment, three-axis acceleration and three-axis angular velocity after compensation, feedback through control algorithm, and continuous correction of current robot body (3) end pose until the assembly part (7) and the to-be-assembled surface (811) complete the expected surface fitting effect.

5. The control method of claim 4, wherein, Step S1 specifically includes: S11, construct the world coordinate system O w -X w Y w Z w , the robot body (3) coordinate system is O r -X r Y r Z r , the robot end connecting flange (5) coordinate system O f -X f Y f Z f And the force sensor (61) coordinate system is O s -X s Y s Z s ; the Z w axis of the world coordinate system is parallel to the direction of gravity and opposite, the attitude conversion matrix of the force sensor (61) coordinate system relative to the world coordinate system is constructed The formula is expressed as: wherein, a pose conversion matrix of the robot body (3) coordinate system with respect to the world coordinate system; An attitude conversion matrix of a coordinate system of a robot end connecting flange (5) with respect to a coordinate system of a robot body (3); an attitude conversion matrix of the force sensor (61) coordinate system relative to the robot end connecting flange (5) coordinate system; S12, determining the position points of the part assembly fixing component (8), the robot body (3) moves around the position points and stops at six position points, and the coordinates of the robot body (3) in the Cartesian coordinate system at the six position points are obtained: (X, Y, Z, A, B, C), wherein X, Y and Z are the positions of the robot in the Cartesian coordinate system; A, B and C are the poses of the robot in the Cartesian coordinate system; the three-axis force and three-axis moment received by the force sensor (61) at the corresponding coordinates are obtained through real-time receiving by the inertial sensor (63) and Kalman filtering; S13, based on the coordinate system transformation relationship in step S11 and the three-axis force and three-axis moment obtained in step S12, calculate the gravity G and the center of gravity (G) of the components below the force sensor (61) through the gravity center of gravity compensation algorithm x , G y , G z ), the roll angle φ and pitch angle w of the robot body (3), the zero drift value (F x 、F y 、F z 、M x 、M y 、M z ); wherein G x , G y , G z are the X, Y, Z components in the Cartesian coordinate system of the gravity center of mass of the following components of the force sensor (61); F x , F y , F z are the zero-drift three-axis forces of the following components of the force sensor (61); M x , M y , M z are the zero-drift three-axis moments of the following components of the force sensor (61); S14, according to the parameters calculated in step S13, combined with the coordinates of the robot body (3) in the Cartesian coordinate system obtained in real time, and the three-axis force and three-axis torque received by the filtered force sensor (61) under the corresponding coordinates, the actual three-axis force (f x 、 y 、 z f ) and the actual three-axis torque (t x 、 y 、 z t ) generated by the external force on the components below the force sensor (61) are calculated through the zero drift removal algorithm.

6. The control method of claim 4, wherein, Step S2 specifically includes: S21, construct the world coordinate system O w -X w Y w Z w , the robot body (3) coordinate system is O r -X r Y r Z r , the robot end connecting flange (5) coordinate system O f -X f Y f Z f And the inertial sensor (63) coordinate system O g -X g Y g Z g , the Z w axis of the world coordinate system is parallel to the direction of gravity and opposite, the attitude conversion matrix of the inertial sensor (63) coordinate system relative to the world coordinate system is constructed The formula is expressed as: wherein, a pose conversion matrix of the robot body (3) coordinate system with respect to the world coordinate system; An attitude conversion matrix of a coordinate system of a robot end connecting flange (5) with respect to a coordinate system of a robot body (3); an attitude conversion matrix of the inertial sensor (63) coordinate system relative to the robot end connecting flange (5) coordinate system; S22, determining the position points of the part assembly fixing component (8), the robot body (3) moves around the position points and stops at six position points, and the coordinates of the robot body (3) in the Cartesian coordinate system at the six position points are obtained: (X, Y, Z, A, B, C); the three-axis acceleration and three-axis angular velocity received by the inertial sensor (63) at the corresponding coordinates are obtained through real-time receiving by the inertial sensor (63) and Kalman filtering; S23, based on the coordinate system conversion relationship constructed in step S21 and the three-axis acceleration and three-axis angular velocity obtained in step S22, the calibration coefficients (K x , K y , K z , K a , K b , K c ) and zero drift values (A x , A y , A z , W a , W b , W c ) of the inertial sensor (63) are obtained through an inertial compensation algorithm; wherein K x , K y , K z are the calibration coefficients of the three-axis acceleration received by the inertial sensor (63); K a , K b , K c are the calibration coefficients of the three-axis angular velocity received by the inertial sensor (63); A x , A y , A z are the zero drift values of the three-axis acceleration received by the inertial sensor (63); and W a , W b , W c are the zero drift values of the three-axis angular velocity received by the inertial sensor (63). S24, compensating the inertial sensor (63) according to the calibration coefficient and the zero drift value obtained in step S23; combining the coordinates of the robot body (3) in the Cartesian coordinate system obtained in real time in step S22 and the three-axis acceleration and three-axis angular velocity received by the inertial sensor (63) after filtering under the corresponding coordinates, the actual acceleration (a x , a y , a z ) and actual three-axis angular velocity (w a , w b , w c ) of the end assembly execution member (6) are calculated in real time by a zero drift removal algorithm, and the actual three-axis angular acceleration (a a , a b , a c ) of the end assembly execution member (6) is further calculated.

7. The control method of claim 4, wherein, Step S3 specifically includes: S31, the actual triaxial force, triaxial moment, triaxial acceleration and triaxial angular velocity obtained according to step S1 and step S2 are used to design a mobility control model as a control algorithm of the assembly task, and the formula expression of the mobility control model when the robot body (3) performs one-dimensional translation motion is as follows: where m is a virtual mass; b is a virtual damping; and k is a virtual stiffness. end acceleration of the robot body (3); V is the end velocity of the robot body (3); x is the end position of the robot body (3); f is the actual force acting on the robot body (3) end below the force sensor (61); to the end of the robot body (3) ; desired velocity of the robot body (3) end; x n desired position of the robot body (3) end; f n desired force of the robot body (3) end; a actual acceleration of the robot body (3) end; x n , f n is set to zero, the direction and speed of the assembly task are determined by calculating the difference between x and x n . S32, in order to guarantee the assembly effect and improve the assembly efficiency, reduce the motion rigidity and reduce the vibration amplitude when the collision occurs; when the rebound occurs, increase the motion rigidity, increase the position adjustment time and space, that is, classify the parameter k, and the classification formula is as follows: where k n is the effective virtual stiffness; λ1is a virtual stiffness adjustment parameter 1; λ2is a virtual stiffness adjustment parameter 2; and ρ is an acceleration adjustment parameter. S33, design a mobility control model in one-dimensional rotational motion, the formula is expressed as: wherein a is a virtual rotational inertia; β is a virtual rotational damping; and ψ is a virtual rotational stiffness. for the end angle acceleration of the robot body (3); θ is the rotation angle of the robot body (3) end; t is the actual torque acting on the robot body (3) end below the force sensor (61); to expect an angular acceleration at the end of the robot body (3); θd is the desired angular velocity at the end of the robot body (3) n t is the desired rotation angle at the end of the robot body (3) n a is the desired action torque at the end of the robot body (3) θ ω is the actual angular acceleration at the end of the robot body (3) θ n , t n is set to zero, the direction and speed of the assembly task are determined by calculating the difference between θ and θ n . S34, constantly adjust the pose and monitor in real time, when monitoring the coordinates (X, Y, Z, A, B, C) of the robot body (3) in the Cartesian coordinate system within a certain Δt time, maintain within a certain error fluctuation range, and the actual three-axis force (f x , y , z ) and three-axis torque (t x , y , z ) calculated in real time maintain within a fixed fluctuation range corresponding to the assembly pose, corresponding to the f z parameter, the rest of the f x , y , t x , t y , t z parameters fluctuate around zero; the actual acceleration (a x , y , z ) and the actual angular acceleration (a a , b , c ) calculated in real time maintain fluctuation around zero, it is considered that the assembly task is completed.

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