Robot grinding device based on PLC and control method

Abstract

The invention belongs to the field of grinding equipment, and provides a robot grinding device based on a PLC and a control method, the device comprises a device shell, and a mounting block, an air cylinder driving part, a magnetic displacement sensor, a linear guide rail, an electric proportional valve, an electromagnetic valve, an angle sensor and the PLC are arranged in the device shell. According to the grinding device, firstly, the angle sensor is used for recognizing the posture state of the whole grinding device in a three-dimensional space, then the gravity of a tool in the corresponding space posture is calculated through the PLC in combination with the content of the control method, and then the thrust provided by the air cylinder driving part is precisely controlled through the precise electric proportional valve; in this way, the air cylinder can change thrust in real time according to user requirements while making up the gravity of a tool in any spatial posture, and therefore the contact force with a workpiece is kept constant.

Description

Technical Field

[0001] The invention belongs to the field of grinding equipment, and in particular relates to a PLC-based robot grinding device and a control method. Background Art

[0002] At present, the equipment for grinding industrial products such as die-castings, injection molded parts, and machined parts requires constant force control, which is specifically to maintain the uniformity of the grinding surface texture and keep the contact force of all grinding tracks constant. However, most constant force grinding devices on the market simply use cylinders to provide thrust, and use their thrust to always keep the grinding device close to the surface of the workpiece. The force applied to the surface of the workpiece increases with the compression of the cylinder. At present, traditional floating constant force grinding devices have the following problems:

[0003] 1. The load weight at different spatial angles will affect the output pressure;

[0004] 2. Poor control accuracy;

[0005] 3. It does not have the pressure feedback function and cannot accurately know the current output pressure; Summary of the invention

[0006] In order to overcome the above-mentioned shortcomings of the prior art, an object of the present invention is to provide a PLC-based robot grinding device.

[0007] The technical solution adopted by the present invention to solve its technical problem is:

[0008] A PLC-based robot polishing device comprises a device housing, wherein a mounting block, a cylinder driving member, a magnetic displacement sensor, a linear guide rail, an electric proportional valve, a solenoid valve, an angle sensor and a PLC controller are arranged in the device housing;

[0009] The PLC controller is electrically connected to the magnetic displacement sensor, the electrical proportional valve, the solenoid valve, and the angle sensor;

[0010] The driving end of the cylinder driving member is connected to the mounting block, the mounting block is slidably matched with the linear guide rail, and a floating flange is provided on the mounting block;

[0011] The magnetic displacement sensor is used to detect the displacement of the driving end of the cylinder driving member;

[0012] The cylinder driving component is connected to the electrical proportional valve and the solenoid valve respectively.

[0013] Preferably, the device housing includes a base plate, an outer shell and an upper cover, the outer shell is connected to the base plate and forms a cavity for placing the mounting block, cylinder drive, magnetic displacement sensor, linear guide, electric proportional valve, solenoid valve, angle sensor and PLC controller, the upper cover is installed at the cavity mouth of the cavity, an opening is provided at the upper cover, the floating flange is relatively arranged on the outside of the device housing, one end of the floating flange passes through the opening and is connected to the mounting block.

[0014] Preferably, connecting bolts for connecting the upper cover are provided at the four corners of the bottom plate, and the outer shell is sleeved on the connecting bolts.

[0015] Preferably, the cavity is divided into a first area, a second area, a third area and a fourth area, wherein the first area, the second area, the third area and the fourth area are arranged around the center of the cavity in a clockwise direction;

[0016] The electrical proportional valve, solenoid valve, angle sensor and PLC controller are arranged in the first area, the cylinder drive is arranged in the second area, the magnetic displacement sensor is arranged in the third area, and the linear guide rail and mounting block are arranged in the fourth area;

[0017] The cylinder driving member comprises a cylinder piston rod, which is the driving end of the cylinder driving member. One end of the cylinder piston rod is connected to the mounting block, and the detection end of the magnetic displacement sensor is arranged toward the cylinder piston rod.

[0018] Preferably, a mounting seat for fixing the cylinder driving member is provided in the second area.

[0019] Preferably, an elastic dust cover is provided at the connection between the floating flange and the mounting block, and the elastic dust cover is arranged at the opening.

[0020] Preferably, it further comprises limit blocks, wherein the limit blocks are arranged at both ends of the linear guide rail;

[0021] The linear guide rail comprises two guide rail members arranged in parallel, and the limit block is arranged between the two guide rail members.

[0022] Preferably, a positioning pin and a stopper are provided on the limit block, the limit block is connected to the device housing via the positioning pin, the stopper is made of a soft material, and the stopper is arranged toward the mounting block.

[0023] The present invention also includes a control method for a PLC-based robot polishing device, based on the above-mentioned PLC-based robot polishing device, comprising the following steps:

[0024] S1. Determine the load gravity on the floating flange, where the parallel component of the load gravity is calculated by the formula: F parallel =mg*sin(θ), to obtain the load gravity on the floating flange; wherein, m is the mass of the object, g is the acceleration of gravity, and θ is the inclination angle of the inclined plane;

[0025] S2. Add the floating flange output pressure setting value and the load gravity, and calculate the output direction of the actuator cylinder based on the positive and negative values;

[0026] S3. According to the above output direction, it is determined whether the driving end of the cylinder driving part is thrust or tension. According to the formula: thrust on the driving end of the cylinder driving part: F1 = π / 4*D2*P, tension on the driving end of the cylinder driving part: F2 = π / 4*(D2-d 2 )*P, where F1: the thrust when the driving end of the cylinder driving part is pushed out, F2: the pulling force when the driving end of the cylinder driving part is pulled back, D: the inner diameter of the cylinder tube of the cylinder driving part, d: the diameter of the cylinder piston rod, P: the pressure of the input air source of the cylinder driving part to calculate the output air pressure required;

[0027] S4, burr friction coefficient compensation in thrust and pull directions;

[0028] S5, according to the calculated required air pressure and direction, output analog quantity to control the output air pressure of the electrical proportional valve and the switching direction of the solenoid valve;

[0029] S6, by feeding back the actual output pressure from the electric proportional valve, the current output pressure is obtained by reverse calculation to serve as a feedback prompt.

[0030] Preferably, in step S4, the friction force is determined as follows:

[0031] s41. Gravity components: First calculate the total gravity of the object on the inclined surface of the floating flange, and then decompose it into two components parallel and perpendicular to the inclined surface. The formula is as follows:

[0032] Parallel component: F parallel = mg*sin(θ);

[0033] Vertical component: F normal = mg*cos(θ);

[0034] Among them, m is the mass of the object, g is the acceleration due to gravity, and θ is the inclination angle of the inclined plane.

[0035] s42. Determine the normal pressure: Normal pressure is equal to the weight component of the object perpendicular to the inclined plane, N = F normal ;

[0036] s43. Determine the friction force: The magnitude of the friction force depends on the friction coefficient (μ) and the normal pressure on the inclined surface, Ffriction =μ*N, and the burr friction coefficient is compensated according to the above friction force.

[0037] Compared with the prior art, the beneficial effects of the present invention include:

[0038] Through the above structure and control method, the present application first uses an angle sensor to identify the position state of the entire grinding device in three-dimensional space, and then calculates the gravity of the tool in the corresponding spatial position through a PLC controller combined with the above control method content, and then accurately controls the thrust provided by the cylinder drive component through a precision electrical proportional valve. In this way, in any posture in space, the cylinder can compensate for the gravity of the tool while following the user's requirements to change the thrust in real time, thereby keeping the contact force with the workpiece constant. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0040] Figure 1 It is a front view of the present invention.

[0041] Figure 2 for Figure 1 AA section view of the .

[0042] Figure 3 It is the internal structure diagram of the present invention.

[0043] Figure 4 It is a schematic diagram of the structural decomposition of the present invention.

[0044] Figure 5 It is a schematic diagram of the tilted state relative to the horizontal plane of the present invention.

[0045] in:

[0046] 1-mounting block, 2-cylinder drive, 3-magnetic displacement sensor, 4-linear guide, 5-electric proportional valve, 6-solenoid valve, 7-angle sensor, 8-floating flange, 9-base plate, 10-housing, 11-upper cover, 12-connecting bolt, 13-limit block, 14-stopper, 15-opening, 16-mounting seat. DETAILED DESCRIPTION

[0047] In order to more clearly understand the above-mentioned objects, features and advantages of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, in the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other. In the following description, many specific details are set forth in order to fully understand the present invention, and the embodiments described are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the art without making creative work are within the scope of protection of the present invention.

[0048] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0049] Example:

[0050] like Figure 1-4 As shown, in this embodiment, a PLC-based robot grinding device is provided, including a device housing, in which a mounting block 1, a cylinder driving member 2, a magnetic displacement sensor 3, a linear guide 4, an electric proportional valve 5, a solenoid valve 6, an angle sensor 7 and a PLC controller are arranged;

[0051] The PLC controller is electrically connected to the magnetic displacement sensor 3, the electrical proportional valve 5, the solenoid valve 6, and the angle sensor 7;

[0052] The driving end of the cylinder driving member 2 is connected to the mounting block 1, the mounting block 1 is slidably matched with the linear guide rail 4, and a floating flange member 8 is provided on the mounting block 1;

[0053] The magnetic displacement sensor 3 is used to detect the displacement of the driving end of the cylinder driving member 2;

[0054] The cylinder driving component 2 is connected to the electric proportional valve 5 and the solenoid valve 6 respectively.

[0055] In the above structure, the floating flange 8 is connected to the external tool. When the tool is working with the outside world, its force is transmitted to the cylinder driver 2 through the mounting block 1 and the linear guide 4, causing the driving end of the cylinder driver 2 to be displaced. The displacement value is monitored in real time by the magnetic displacement sensor 3, and is fed back to the PLC controller for precise control of the electric proportional valve 5 to achieve constant force control. At the same time, this embodiment needs to reduce its own friction to achieve the effect of constant force control. Therefore, the linear guide 4 and the cylinder driver 2 used have low friction characteristics. The comprehensive performance is reflected in that the overall grinding device can be tilted without applying external force, and the internal structure of the grinding device is displaced under its own gravity.

[0056] The specific structure of the device shell of this embodiment is as follows:

[0057] The device housing includes a base plate 9, an outer shell 10 and an upper cover 11. The outer shell 10 is connected to the base plate 9 and forms a cavity for placing a mounting block 1, a cylinder driver 2, a magnetic displacement sensor 3, a linear guide 4, an electric proportional valve 5, a solenoid valve 6, an angle sensor 7 and a PLC controller. The upper cover 11 is installed at the cavity mouth of the cavity. An opening 15 is provided at the upper cover 11. A floating flange 8 is relatively arranged on the outside of the device housing. One end of the floating flange 8 passes through the opening and is connected to the mounting block 1.

[0058] Specifically, connecting bolts 12 for connecting the upper cover 11 are provided at the four corners of the bottom plate 9 , and the outer shell 10 is sleeved on the connecting bolts 12 .

[0059] In the above structure, the base plate 9, the shell 10 and the upper cover 11 are made of aluminum alloy, and are connected by connecting bolts 12 and the shell 10 is sleeved and nested between the base plate 9 and the upper cover 11, which is easy to install and can also ensure the overall lightness.

[0060] The device components of this embodiment adopt a modular layout, specifically dividing the cavity of the device housing into a first area, a second area, a third area and a fourth area, wherein the first area, the second area, the third area and the fourth area are arranged around the center of the cavity in a clockwise direction;

[0061] The electric proportional valve 5, the solenoid valve 6, the angle sensor 7 and the PLC controller are arranged in the first area, the cylinder drive 2 is arranged in the second area, the magnetic displacement sensor 3 is arranged in the third area, and the linear guide 4 and the mounting block 1 are arranged in the fourth area;

[0062] The cylinder driving member 2 includes a cylinder piston rod, which is the driving end of the cylinder driving member 2. One end of the cylinder piston rod is connected to the mounting block 1, and the detection end of the magnetic displacement sensor 3 is arranged toward the cylinder piston rod.

[0063] Specifically, a mounting seat 16 for fixing the cylinder driving member 2 is provided in the second area.

[0064] The above structure can ensure that the various device components are arranged compactly in the device housing. At the same time, the various device components are arranged in various areas so that they do not interfere with each other while realizing their respective functions, which is convenient for installation.

[0065] In this embodiment, an elastic dust cover is provided at the connection between the floating flange 8 and the mounting block 1, and the elastic dust cover is provided at the opening. The elastic dust cover covers and seals the opening, and when the mounting block 1 moves relative to the opening, the elastic structure of the elastic dust cover will not affect its movement process.

[0066] This embodiment further includes a limit block 13, which is disposed at both ends of the linear guide rail 4;

[0067] The linear guide rail 4 includes two guide rail members arranged in parallel, and the limit block 13 is arranged between the two guide rail members.

[0068] Specifically, a positioning pin and a stopper 14 are provided on the limit block 13 . The limit block 13 is connected to the device housing via the positioning pin. The stopper 14 is made of a soft material and is arranged toward the mounting block 1 .

[0069] In the above limiting structure, the positioning pin ensures the accuracy of the mounting block 1 under the action of repeated impact on the limiting block 13 during operation; at the same time, the limiting block 13 is made of aluminum alloy, and the stopper 14 installed at its front end is made of soft material to reduce the impact and noise caused by the collision.

[0070] At the same time, the present invention also includes a control method for a PLC-based robot polishing device, based on the above-mentioned PLC-based robot polishing device, comprising the following steps:

[0071] S1. Determine the load gravity on the floating flange 8, where the parallel component of the load gravity is calculated by the formula: F parallel = mg*sin(θ), and the load gravity on the floating flange 8 is obtained; where m is the mass of the object, g is the acceleration of gravity, and θ is the inclination angle of the inclined plane. Figure 5 Specifically, the angle sensor 7 can detect the position state of the grinding device in three-dimensional space to obtain the inclination angle of the workpiece and the end face of the floating flange 8, that is, the inclination angle of the bevel.

[0072] S2. Add the floating flange output pressure setting value and the load gravity, and calculate the output direction of the actuator cylinder based on the positive and negative values;

[0073] S3. According to the above output direction, it is determined whether the driving end of the cylinder driving member 2 is a thrust or a pull. According to the formula: the thrust on the driving end of the cylinder driving member 2: F1 = π / 4*D2*P, the pull on the driving end of the cylinder driving member 2: F2 = π / 4*(D2-d 2 )*P, where F1: thrust when the driving end of the cylinder driving member 2 is pushed out, F2: pulling force when the driving end of the cylinder driving member 2 is pulled back, D: inner diameter of the cylinder tube of the cylinder driving member 2, d: diameter of the cylinder piston rod, P: pressure of the input air source of the cylinder driving member 2 for calculating the output air pressure required;

[0074] S4, burr friction coefficient compensation in thrust and pull directions;

[0075] S5, according to the calculated required air pressure and direction, output analog quantities to control the output air pressure of the electrical proportional valve 5 and the switching direction of the solenoid valve 6;

[0076] S6, by feeding back the actual output air pressure from the electric proportional valve 5, the current output pressure is obtained by reverse calculation to serve as a feedback prompt.

[0077] Specifically, in step S4, the friction force is determined as follows:

[0078] s41. Gravity components: First, calculate the total gravity of the object on the inclined surface of the floating flange 8, and then decompose it into two components parallel and perpendicular to the inclined surface. The formula is as follows:

[0079] Parallel component: F parallel = mg*sin(θ);

[0080] Vertical component: F normal = mg*cos(θ);

[0081] Among them, m is the mass of the object, g is the acceleration due to gravity, and θ is the inclination angle of the inclined plane.

[0082] s42. Determine the normal pressure: Normal pressure is equal to the weight component of the object perpendicular to the inclined plane, N = F normal ;

[0083] s43. Determine the friction force: The magnitude of the friction force depends on the friction coefficient (μ) and the normal pressure on the inclined surface, F friction =μ*N, and the burr friction coefficient is compensated according to the above friction force.

[0084] Through the above structure and control method, the grinding device first uses the angle sensor 7 to identify the posture state of the overall grinding device in three-dimensional space, and then calculates the gravity of the tool in the corresponding spatial posture through the PLC controller combined with the above control method content, and then accurately controls the thrust provided by the cylinder driver 2 through the precision electrical proportional valve 5. In this way, the cylinder can compensate for the gravity of the tool in any posture in space and change the thrust in real time according to user requirements, thereby keeping the contact force with the workpiece constant. The angle sensor 7 of the present application can identify the angle, and can keep the output pressure constant at any spatial angle, and automatically calculate and compensate for the influence of the load weight; by compensating for the burr friction coefficient in the thrust and pull directions, high-precision control is achieved; at the same time, the magnetic displacement sensor 3 enables it to have a pressure feedback function, and accurately know the current actual output pressure.

[0085] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Therefore, any modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of the technical solution of the present invention.

Claims

1. A PLC-based robot polishing device, characterized in that: include: A device housing, wherein a mounting block, a cylinder drive, a magnetic displacement sensor, a linear guide, an electrical proportional valve, a solenoid valve, an angle sensor and a PLC controller are arranged in the device housing; The PLC controller is electrically connected to the magnetic displacement sensor, the electrical proportional valve, the solenoid valve, and the angle sensor; The driving end of the cylinder driving member is connected to the mounting block, the mounting block is slidably matched with the linear guide rail, and a floating flange is provided on the mounting block; The magnetic displacement sensor is used to detect the displacement of the driving end of the cylinder driving member; The cylinder driving component is connected to the electrical proportional valve and the solenoid valve respectively.

2. The PLC-based robot polishing device according to claim 1, characterized in that: The device housing includes a base plate, an outer shell and an upper cover, the outer shell is connected to the base plate and forms a cavity for placing the mounting block, the cylinder drive, the magnetic displacement sensor, the linear guide, the electric proportional valve, the solenoid valve, the angle sensor and the PLC controller, the upper cover is installed at the cavity mouth of the cavity, the upper cover is provided with an opening, the floating flange is relatively arranged on the outside of the device housing, one end of the floating flange passes through the opening and is connected to the mounting block.

3. The PLC-based robot polishing device according to claim 2, characterized in that: The four corners of the bottom plate are provided with connecting bolts for connecting the upper cover, and the outer shell is sleeved on the connecting bolts.

4. The PLC-based robot polishing device according to claim 2, characterized in that: The cavity is divided into a first area, a second area, a third area and a fourth area, wherein the first area, the second area, the third area and the fourth area are arranged around the center of the cavity in a clockwise direction; The electrical proportional valve, solenoid valve, angle sensor and PLC controller are arranged in the first area, the cylinder drive is arranged in the second area, the magnetic displacement sensor is arranged in the third area, and the linear guide rail and mounting block are arranged in the fourth area; The cylinder driving member comprises a cylinder piston rod, which is the driving end of the cylinder driving member. One end of the cylinder piston rod is connected to the mounting block, and the detection end of the magnetic displacement sensor is arranged toward the cylinder piston rod.

5. The PLC-based robot polishing device according to claim 4, characterized in that: A mounting seat for fixing the cylinder driving member is provided in the second area.

6. The PLC-based robot polishing device according to claim 2, characterized in that: An elastic dust cover is provided at the connection between the floating flange and the mounting block, and the elastic dust cover is arranged at the opening.

7. The PLC-based robot polishing device according to claim 1, characterized in that: It also includes limit blocks, which are arranged at both ends of the linear guide rail; The linear guide rail comprises two guide rail members arranged in parallel, and the limit block is arranged between the two guide rail members.

8. The PLC-based robot polishing device according to claim 7, characterized in that: The limit block is provided with a positioning pin and a stopper, the limit block is connected to the device housing through the positioning pin, the stopper is made of a soft material, and the stopper is arranged toward the mounting block.

9. A control method for a PLC-based robot polishing device, characterized in that: The PLC-based robot polishing device according to any one of claims 1 to 8 comprises the following steps: S1. Determine the load gravity on the floating flange, where the parallel component of the load gravity is calculated by the formula: F parallel =mg*sin(θ), to obtain the load gravity on the floating flange; wherein, m is the mass of the object, g is the acceleration of gravity, and θ is the inclination angle of the inclined plane; S2. Add the floating flange output pressure setting value and the load gravity, and calculate the output direction of the actuator cylinder based on the positive and negative values; S3. According to the above output direction, it is determined whether the driving end of the cylinder driving part is thrust or tension. According to the formula: Thrust on the driving end of the cylinder driving part: F1 = π / 4*D 2 *P, the tension on the driving end of the cylinder drive: F2 = π / 4*(D 2 -d 2 )*P, where F1: the thrust when the driving end of the cylinder driving part is pushed out, F2: the pulling force when the driving end of the cylinder driving part is pulled back, D: the inner diameter of the cylinder tube of the cylinder driving part, d: the diameter of the cylinder piston rod, P: the pressure of the input air source of the cylinder driving part to calculate the output air pressure required; S4, burr friction coefficient compensation in thrust and pull directions; S5, according to the calculated required air pressure and direction, output analog quantity to control the output air pressure of the electrical proportional valve and the switching direction of the solenoid valve; S6, by feeding back the actual output pressure from the electric proportional valve, the current output pressure is obtained by reverse calculation to serve as a feedback prompt.

10. The control method of the PLC-based robot polishing device according to claim 1, characterized in that: In step S4, the friction force is determined as follows: s41. Gravity components: First calculate the total gravity of the object on the inclined surface of the floating flange, and then decompose it into two components parallel and perpendicular to the inclined surface. The formula is as follows: Parallel component: F parallel = mg*sin(θ); Vertical component: F normal = mg*cos(θ); Among them, m is the mass of the object, g is the acceleration due to gravity, and θ is the inclination angle of the inclined plane. s42. Determine the normal pressure: Normal pressure is equal to the weight component of the object perpendicular to the inclined plane, N = F normal ; s43. Determine the friction force: The magnitude of the friction force depends on the friction coefficient (μ) and the normal pressure on the inclined surface, F friction =μ*N, and the burr friction coefficient is compensated according to the above friction force.

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