Pull-type device of concrete spreader and construction method of pull-type device

Abstract

The invention discloses a traction type device of a concrete spreader and a construction method thereof, the device comprises an XYZ three-dimensional force sensor, a set of spherical hinge traction device and a buffer damping structure, the device can filter part of interference force generated at the tail end of a mechanical arm due to concrete pumping, and traction force applied by workers within a certain height can be accurately measured. According to the rotation transformation matrix, obtaining the representation of the traction force under the base coordinate, and carrying out self-adaptive admittance control according with the actual construction, so as to realize the transformation from force to displacement; closed-loop feedback control is combined to realize traction construction operation; the construction method based on the traction type device is suitable for two construction working conditions, a worker pulls a traction rod of an execution part according to the construction working conditions, the tail end of a concrete hose of the concrete spreader is adjusted to the position above a pouring position in real time, and pouring operation is achieved. According to the pull-type device of the concrete spreader and the construction method of the pull-type device, the construction efficiency of pouring concrete by using the spreader can be greatly improved, the construction safety is ensured, and the construction intensity of workers is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of engineering machinery, and specifically discloses a traction device of a concrete placing boom and a construction method thereof. Background Art

[0003] The concrete placing machine can deliver concrete to any part of the working surface for pouring quickly and accurately like a robot, which solves the problem of concrete distribution, reduces labor intensity, and improves construction efficiency and quality. Usually, the concrete placing operation is carried out in a small range by manually pulling the end of the concrete hose, while the control of the tower is relied on for larger-scale operations. This mixed operation method has a great potential safety hazard in construction. Workers need to bear considerable labor intensity in this method, and the operation efficiency is not high.

[0004] When the end of the robotic arm is subjected to traction, it can be considered to identify it and convert it into a joint angle compensation signal in real time through an algorithm, and the controller will perform real-time compensation. This method of identifying the end force without installing a sensor at the end is called a "soft measurement method of end force". There is currently a soft measurement method for the end force of a hydraulic robotic arm based on parameter identification, such as patent publication number CN113977578A, which was applied for by this team on October 26, 2021. Although this method can accurately measure the end force of a heavy-loaded arm, its force measurement accuracy does not meet the construction standards when facing a concrete placing boom with long flexibility and unstable vibration.

[0005] In order to solve the major safety hazards in the construction process of concrete placing boom, reduce the labor intensity of workers and improve construction efficiency, a mechanical structure that can accurately identify the force at the end of the mechanical arm and a traction construction method based on this structure are proposed. Summary of the invention

[0006] To this end, the present invention discloses a traction device of a concrete placing boom and a construction method thereof. The traction device is fixedly connected to the end of the third arm of the main part of the placing boom. It provides workers with traction operations and identifies the force signals applied by the workers, filtering a part of the irregular vibration force generated by pumping concrete to a certain extent; establishes a force rotation transformation matrix, uses a specific admittance controller, regulates the force signals in three directions in accordance with the actual construction, and outputs a position signal; finally, the position, velocity and acceleration information are inversely solved by the gradient projection method to obtain the angle information of each arm joint angle, and then the moving distance of the hydraulic rod is obtained through the amplitude change mechanism, and the hydraulic system is closed-loop controlled to drive the end of the mechanical arm to the traction position.

[0007] The technical solution adopted by the present invention is: a traction device of a concrete placing boom, the device comprising: an XYZ three-dimensional force sensor, a set of ball joint traction devices and a buffer shock absorbing structure.

[0008] Furthermore, a welding block is provided on the top of the traction device, which is fixed by welding at the downward position of the end of the third arm rod. The welding block is connected to the three-dimensional force sensor, the three-dimensional force sensor is connected to the ball joint base, the ball joint base is connected to the ball joint cover, and the connection forms a spherical inner cavity. The ball joint component is placed in the spherical inner cavity to form a spherical pair. Shock-absorbing rubber is placed between the ball joint base and the ball joint cover to buffer the vibration force generated by pumping concrete. The ball joint component is connected to the traction rod.

[0009] Furthermore, there are two shock-absorbing rubbers, which cover the ball joint and are placed together in the spherical space formed by the ball joint base and the ball joint cover; the shock-absorbing rubber has a convex portion along its own circumferential direction, and the ball joint base and the ball joint cover cooperate to form a groove portion, and the two form a stable mortise and tenon structure when assembled.

[0010] Furthermore, the shock-absorbing rubber and band-stop filtering methods eliminate the vibration force generated at the end of the third boom due to pumping concrete at the physical structure and algorithm levels, respectively, and accurately obtain the target force applied by the workers.

[0011] Furthermore, the force signal at a certain height is collected, and the base coordinate system is obtained by combining the rotation angle of the turntable and the three arm joint information. To the three-dimensional force sensor coordinate system The rotation matrix is:

[0012]

[0013] is the three-dimensional force sensor coordinate system With the primary boom coordinate system The angle formed, The turntable coordinate system With base coordinate system The angle formed.

[0014] Furthermore, the force measured by the three-dimensional force sensor Transformed into the base coordinate system The following expression .

[0015] Furthermore, the admittance control equation is:

[0016]

[0017] in , , Indicates the actual position, velocity and acceleration of the three-dimensional force sensor; , , Represents the desired position, velocity, and acceleration. , , It is the set admittance parameter, which is designed to be dynamically adjusted according to the force. is the static force in that direction.

[0018] Further, refer to Figure 1 , the position expressions of the end of the concrete placing boom in the R direction (working radius direction), Y direction (rotation direction) and Z direction (vertical direction) are:

[0019]

[0020] in , , is the length of each arm of the robot, is the desired rotation angle of the horizontal working surface.

[0021] Furthermore, in the turntable coordinate system In the XOZ plane, the partial derivative of the end position of the robot arm with respect to each joint angle is obtained and expressed by the Jacobian matrix as follows:

[0022]

[0023] Furthermore, the relationship between the compensation angle and the position deviation is:

[0024]

[0025] Furthermore, the compensation angle Through the mapping relationship of the luffing mechanism, it is converted into the telescopic length of the hydraulic rod The difference between the actual rod length and the expected rod length is used for PID algorithm control, which is used as the feedback input signal of the hydraulic valve to adjust the angles of each joint in real time. The robot arm moves stably on the XOY plane of the arm coordinate system following the external force traction.

[0026] Furthermore, the control signal of the rotating plane is related to the rotating angle, and feedback adjustment control is performed.

[0027] On the other hand, the present invention also provides a construction method based on the above-mentioned traction device, and the construction method includes the following two construction conditions:

[0028] Horizontal construction conditions: dragging the traction rod angle If the set value is exceeded, the traction control in the Z direction will not be performed, and the construction surface will be a horizontal surface with a fixed height;

[0029] Vertical adjustment condition: drag the drawbar angle If it is less than the set value, there will be no traction control in the horizontal direction and the construction surface will be a fixed vertical line.

[0030] The beneficial effects achieved by the present invention are as follows:

[0031] (1) The traction device of the present invention adopts a standardized and modular design, which makes assembly and maintenance more convenient and can significantly reduce the cost of workers in the assembly and maintenance process.

[0032] (2) The traction device of the present invention simplifies the rotation conversion matrix and adopts two methods to reduce the interference of forces and accurately measure the traction force applied by workers at a certain height.

[0033] (3) The present invention provides different control methods for two working conditions, sets the maximum traction speed and the maximum traction threshold, and prevents mechanical damage caused by accidental construction. It greatly reduces the labor intensity of workers, simplifies the work process, and improves construction efficiency through traction-type construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0036] Figure 2 The structure of the traction device of the present invention is shown in FIG. Figure 1 .

[0037] Figure 3 The structure of the traction device of the present invention is shown in FIG. Figure 2 .

[0038] Figure 4 It is a flow chart of the traction device of the present invention.

[0039] Figure 5 It is the principle diagram of the traction device of the present invention.

[0040] Figure 6 It is a module diagram of the traction device of the present invention. Specific implementation methods

[0041] In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the drawings and embodiments, but the content of the present invention is not limited to the following embodiments. Example 1

[0042] like Figure 1 As shown, the execution part of the traction construction is fixedly connected to the end of the main part of the concrete placing machine, including a welding block (7), a three-dimensional force sensor (8), a ball joint base (9), a shock-absorbing rubber (10), a ball joint cover (11), a ball joint member (12), a traction rod (13) and a plurality of screws, bolts and nuts.

[0043] The execution part of the traction construction is provided with a welding block at its top, which is fixed at the downward position of the end of the third arm by welding. A three-dimensional force sensor is provided below the welding block, a ball joint base is provided below the three-dimensional force sensor, and a ball joint cover is provided below the ball joint base. The connection forms a spherical inner cavity, and the ball joint is placed in the spherical inner cavity to form a spherical pair. Shock-absorbing rubber is placed between the ball joint base and the ball joint cover to buffer the vibration force generated by pumping concrete. A traction rod is provided below the ball joint and connected by bolts.

[0044] Ensure that the connection surface between the welding block and the three-dimensional force sensor is in the same plane as the third joint rotation axis, reduce the amount of calculation, and improve the force conversion accuracy. The force signal measured by the three-dimensional sensor is transmitted to the main unit of the material placing machine through the bus. The bus is arranged along each arm, leaving a sufficient length of line space at the arm rotation joint.

[0045] The ball joint base and the ball joint cover are both provided with an annular groove at the connection, the radius of the large ring is 55mm, the radius of the small ring is 50mm, and the groove depth is 4mm, which is used to fix the shock-absorbing rubber.

[0046] Furthermore, the shock-absorbing rubber is designed with a raised portion, which forms a stable mortise and tenon structure with the groove formed between the ball joint base and the ball joint cover, see Figure 2 During assembly, first wrap the shock-absorbing rubber around the ball joint, adjust the angle of the raised part, and place it in the groove of the ball joint base. After this step is completed, fasten the ball joint cover and the ball joint base with bolts.

[0047] Furthermore, a gap of 2 mm is left between the ball joint and the spherical inner cavity for placing the shock-absorbing rubber. The thickness of the shock-absorbing rubber is between 3 mm and 4 mm, and the material is soft rubber. After compression, it provides a certain shock-absorbing effect.

[0048] Furthermore, the maximum traction angle of the ball joint cover design is 30 。 .

[0049] Furthermore, threaded holes are provided on both sides of the traction rod and the ball joint, and the traction rod is half-passed through the ball joint and is fastened by two bolts.

[0050] Furthermore, the method used to filter out the vibration force generated by pumping concrete and the force from other sources is band-stop filtering.

[0051] Furthermore, the force signal at a certain height is collected, and the base coordinates are obtained by combining the rotation angle of the turntable and the three arm joint information. To the 3D force sensor coordinates The rotation matrix is:

[0052]

[0053] in , is the three-dimensional force sensor coordinate system With the primary boom coordinate system The angle formed, is the primary arm coordinate system Coordinate system with the turntable The angle formed, is the second arm coordinate system With the primary boom coordinate system The angle formed, is the third arm coordinate system Coordinate system with the second boom The angle formed, The turntable coordinate system With base coordinate system The angle formed.

[0054] Furthermore, the three-dimensional force sensor coordinate system The force signal under the base coordinate system The following is expressed as:

[0055]

[0056] in, It is the expression of the force signal measured by the three-dimensional force sensor in its coordinate system. is the force signal in the base coordinate system The following statement.

[0057] Furthermore, the admittance control equation is:

[0058]

[0059] in , , Indicates the actual position, velocity and acceleration of the three-dimensional force sensor; , , Represents the desired position, velocity, and acceleration. It is the static force in this direction, which can be measured under no-load condition.

[0060] , , It is the set admittance parameter, which is designed to dynamically adjust the parameter size according to the force size. The specific adjustment method is as follows.

[0061] In the X direction:

[0062]

[0063]

[0064]

[0065] in, is the force signal in the base coordinate system The force component in the lower X direction, is the low force threshold in the X direction, is the high threshold in the X direction, For the X direction Adaptive coefficient, For the X direction Adaptive coefficient, For the X direction Adaptive coefficient.

[0066] In the Z direction:

[0067]

[0068]

[0069]

[0070] in, is the force signal in the base coordinate system The component of force in the lower Z direction, is the force threshold in the Z direction.

[0071] In the Y direction.

[0072]

[0073]

[0074]

[0075] in, is the force signal in the base coordinate system The component of force in the lower Y direction, is the low force threshold in the Y direction, is the high threshold in the Y direction, For the Y direction Adaptive coefficient, For the Y direction Adaptive coefficient, For the Y direction Adaptive coefficient.

[0076] Furthermore, to ensure construction safety, the following parameters are restricted:

[0077]

[0078] in is the length of the concrete hose.

[0079] Further, refer to Figure 1 , the position expressions of the end of the concrete placing boom's mechanical arm in the R direction (working radius direction), Y direction (rotation direction) and Z direction (vertical direction) (taking three rods as an example) are:

[0080]

[0081] Further, refer to Figure 1 , the position expressions of the end of the concrete placing boom's mechanical arm in the R direction (working radius direction), Y direction (rotation direction) and Z direction (vertical direction) (taking three rods as an example) are:

[0082]

[0083] in , , is the length of each connecting rod of the fabric placing machine robot arm, is the desired rotation angle of the horizontal working surface.

[0084] Furthermore, in the turntable coordinate system In the XOZ plane, the partial derivative of the end position of the robot arm with respect to each joint angle is calculated:

[0085]

[0086]

[0087] Jacobian matrix It is expressed as:

[0088]

[0089] in Expressed as , Expressed as , Expressed as , , , Similarly:

[0090] The above is expressed as:

[0091]

[0092] Will Perform pseudo-inverse processing to obtain the end position change ΔX to each joint angle 's mapping.

[0093] Furthermore, the compensation angle Through the mapping relationship of the luffing mechanism, it is converted into the telescopic length of the hydraulic rod The difference between the actual rod length and the expected rod length is used for PID algorithm control, which is used as the feedback input signal of the hydraulic valve to adjust the angles of each joint in real time, so that the robot arm can move stably on the XOY plane of the arm coordinate system following the external force traction.

[0094] Furthermore, the control signal of the rotation plane is related to the rotation angle, and the specific relationship is:

[0095]

[0096] in, The actual rotation angle is input into the rotary motor, and the position control of the end of the robot arm in the XOY plane is coordinated to realize the traction operation of the placing crane in the three-dimensional plane.

[0097] On the other hand, the present invention also provides a construction method based on the above-mentioned traction device, and the construction method includes the following two construction conditions:

[0098] (1) Horizontal construction condition: If the traction rod angle exceeds the set value, the traction control in the Z direction will not be performed, and the construction surface will be a horizontal surface with a fixed height;

[0099] (2) Vertical adjustment condition: When the traction rod is dragged to an angle smaller than the set value, no traction control is performed in the horizontal direction, and the adjustment surface is a fixed vertical line.

[0100] in, is the coordinate system of the traction rod relative to the turntable The deflection angle is expressed as:

[0101]

[0102] These two construction conditions cover stable construction in all scenarios and meet the needs of traction operations. At the end of the construction, the bolts of the traction rod and the ball joint are removed, the traction rod is stored in a suitable position, and the concrete placing machine can complete the operation normally.

[0103] The above embodiments are used to illustrate the present invention rather than to limit the present invention. Any modification and change made to the present invention within the spirit of the present invention and the protection scope of the claims shall fall within the protection scope of the present invention.

Claims

1. A traction device for a concrete placing boom, characterized in that: The device includes: A welding block (7), the upper end of which is fixedly connected to the end of the third arm (5) of the concrete placing boom by welding, and the other end is connected to the three-dimensional force sensor (8) by a plurality of screws. A ball joint base (9), one end of which is connected to the three-dimensional force sensor (8) by a plurality of screws, and the other end is connected to the ball joint cover (11) by a plurality of screws, forming a spherical space inside. A shock-absorbing rubber (10), the number of which is two and which covers the ball joint (12), and is placed together in the spherical space formed by the ball joint base (9) and the ball joint cover (11), and a traction rod (13) is connected below the ball joint (12).

2. The traction device of a concrete placing boom according to claim 1, characterized in that: The connection surface between the welding block (7) and the three-dimensional force sensor (8) is in the same plane as the third joint rotation axis, and the shock-absorbing rubber is designed with a raised portion, which forms a stable mortise and tenon structure with the groove formed between the ball joint base and the ball joint cover; during assembly, the shock-absorbing rubber is first wrapped around the ball joint, the angle of the raised portion is adjusted, and it is placed in the groove of the ball joint base, and the ball joint cover and the ball joint base are fastened together by bolts.

3. The traction device of a concrete placing boom according to claim 1, characterized in that: The welding block (7) and the three-dimensional force sensor (8) are fastened by threaded connection, the three-dimensional force sensor (8) and the ball joint base (9) are fastened by threaded connection, the ball joint base (9) and the ball joint cover (11) are fastened by threaded connection, the ball joint component (12) is placed in a spherical space formed by the ball joint base (9) and the ball joint cover (11) to form a spherical pair, the shock-absorbing rubber (10) is placed in the spherical space, sinking grooves are provided on both sides of the ball joint component (12), and the ball joint component (12) and the traction rod (13) are fastened by bolt connection.

4. The traction device of a concrete placing boom according to claim 1, characterized in that: The device can transmit and accurately measure the target force applied by workers at a certain height at the end of the third boom of the concrete placing machine.

5. The traction device of a concrete placing boom according to claim 1, characterized in that: The Denavit-Hartenberg parameter method is used to establish the kinematic model of the concrete placing boom and the three-dimensional force sensor coordinate system To base coordinate system The rotation transformation matrix is: ,in , is the force signal measured by the three-dimensional force sensor in the coordinate system of the rotary table of the fabric machine The vertical angle in the XOZ plane, is the angle between the first arm and the turntable, is the angle between the second arm and the first arm, For three-dimensional force sensors The angle between the line connecting the rotation axes and the third arm, is the rotation angle between the turntable and the base.

6. The traction device of a concrete placing boom according to claim 1, characterized in that: The shock-absorbing rubber (10) and the band-stop filtering method eliminate the vibration force generated at the end of the third arm due to pumping concrete at the physical structure and algorithm levels, respectively, and accurately obtain the traction force applied by the workers.

7. The traction device of a concrete placing boom according to claim 1, characterized in that: Through the adaptive admittance control algorithm, the traction force applied by the workers is converted into position deviation and rotation angle deviation information. The rotation angles of the three arm joint angles are inversely solved based on the gradient projection method. An angle encoder is installed at the arm joint position of the concrete placing boom. Through position feedback, the position of the end of the hydraulically driven robotic arm is closed-loop controlled.

8. A construction method of a traction device of a concrete placing boom according to any one of claims 1 to 7, characterized in that: This construction method includes two construction conditions: (1) Horizontal construction condition: If the traction rod angle exceeds the set value, the traction control in the Z direction will not be performed, and the construction surface will be a horizontal surface with a fixed height to ensure stable construction; (2) Vertical adjustment condition: When the traction rod is dragged to an angle smaller than the set value, no traction control is performed in the horizontal direction, and the adjustment surface is a fixed vertical line.

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