Speed-adjustable servo positioning system and digital control method thereof

Abstract

The invention provides a speed-adjustable servo positioning system and a digital control method thereof, the system comprises an industrial personal computer, a servo driver and a servo object, the industrial personal computer is an integration of an integrated host and a display, the industrial personal computer is a touch operation type industrial personal computer, and the servo object is integrated with a servo motor, an encoder, a speed reducer and a screw rod; the industrial personal computer is sequentially connected with the servo driver and the servo motor in series; the other end of the servo motor main shaft is connected with the speed reducer; the reducer output shaft is connected with the lead screw through a nut; the servo positioning system has the advantages of few control devices, simple interface, convenience in connection and low cost. The servo positioning system controlled by using the digital control method of the speed-adjustable servo positioning system can realize feedback of state variables such as displacement, speed and the like, and the system is adjustable in response speed, high in positioning precision and hard in characteristic; control parameters in the digital control method are referenced by a calculation formula, the control parameters can be quickly debugged according to the formula, and time is saved.

Description

Technical Field

[0001] The present invention relates to a positioning control system, and in particular to a servo positioning system with high precision, hard characteristics and adjustable speed implemented by digital methods and its digital control method, belonging to the technical field of servo control. Background Art

[0002] Vehicle leveling technology is currently widely used in the fields of engineering vehicles and military special vehicles, such as vehicle-mounted drilling platforms, radar antenna vehicles, missile launch vehicles, missile transfer vehicles, etc. In these special vehicles that require leveling, a single leg, as an important part of the multi-leg leveling system, its response speed and control accuracy directly affect the leveling performance of the entire vehicle. In the multi-leg leveling system, in order to meet the requirement of short final leveling time, it is desired that different legs adopt different extension speeds according to the required extension displacement. That is to say, the leg with a long displacement output needs to be fast, and the leg with a short displacement output needs to be relatively slow, so as to achieve the ideal situation that all legs are finally synchronized to quickly level the vehicle.

[0003] Existing electric leveling systems often use electric cylinders and their supporting servo drivers. For the control of a single leg electric cylinder, the PID control method built into the servo driver supporting the electric cylinder is generally used. Although the PID control has a simple structure and a wide range of applications, the control effect is often not optimal, which is reflected in aspects such as uncontrollable response speed during positioning, non-hard load characteristics, and dependence on manual experience for adjusting control parameters; on the other hand, existing leveling systems generally also use a multi-axis motion control module as the controller, which increases the cost of the leveling system to a certain extent.

[0004] With the improvement of users' requirements for the comprehensive performance of the leveling system, the currently widely used leveling methods can no longer meet the needs. Adopting a new low-cost, high-performance speed-adjustable servo positioning system and its digital control method is the key to improving the market competitiveness of the entire leveling system. Summary of the Invention

[0005] Object of the Invention: The object of the present invention is to solve the problems existing in the above-mentioned existing products, and to provide an electric cylinder fast positioning servo system and its digital control method. One object is to provide a servo positioning system with high precision, hard characteristics and adjustable speed implemented by digital methods. Another object of the present invention is to provide a digital control method for the speed-adjustable servo positioning system.

[0006] Technical solution: A servo positioning system with adjustable speed according to the present invention includes an industrial control computer, a servo driver, and a servo object. The servo object integrates a servo motor, an encoder, a reducer, and a lead screw. The industrial control computer is cascaded with the servo driver and the servo motor in sequence. One end of the main shaft of the servo motor is connected to the encoder, and the other end is connected to the reducer. The output shaft of the reducer is connected to the lead screw, and the encoder is connected to the servo driver.

[0007] Preferably, the industrial control computer is an integrated industrial control computer integrating a host and a display, with touch operation.

[0008] Preferably, the output shaft of the reducer is connected to the lead screw through a nut.

[0009] Preferably, the industrial control computer is connected to the servo driver through an Ethernet interface and communicates using the Modbus communication protocol. The servo driver is connected to the servo motor through a PWM output interface.

[0010] A digital control method for a servo positioning system with adjustable speed according to the present invention includes the following steps:

[0011] Step 1, the industrial control computer periodically detects the lead screw displacement signal R r and the maximum speed signal V max input by the user therein, and transmits V max to the corresponding address of the servo driver;

[0012] Step 2, the industrial control computer multiplies the lead screw displacement signal R r by the multiplication coefficient K P1 , and obtains the multiplication operation result M1 = K P1 ×R r ;

[0013] Step 3, the industrial control computer performs a subtraction operation on the multiplication operation result M1 and the displacement signal θ f transmitted by the servo driver, and obtains the subtraction operation result S1 = M1 - θ f ;

[0014] Step 4, the industrial control computer integrates the subtraction operation result S1 to obtain the integration result I1 = I1 + S1;

[0015] Step 5, the industrial control computer multiplies the integration result I1 by the multiplication coefficient K P2 , and obtains the multiplication operation result M2 = K P2 ×I1;

[0016] Step 6, the industrial control computer multiplies the displacement signal θ f transmitted by the servo driver by the multiplication coefficient K P3 , and obtains the multiplication operation result M3 = K P3 ×θ f ;

[0017] Step 7, the industrial control computer performs a subtraction operation on the multiplication result M2 and the multiplication result M3 to obtain a subtraction result S2 = M2 - M3;

[0018] Step 8, the industrial control computer multiplies the speed signal ω f transmitted by the servo drive by a multiplication coefficient K P4 , to obtain a multiplication result M4 = K P4 ×ω f ;

[0019] Step 9, the industrial control computer performs a subtraction operation on the subtraction result S2 and the multiplication result M4 to obtain a subtraction result S3 = S2 - M4;

[0020] Step 10, the industrial control computer integrates the subtraction result S3 to obtain an integration result I2 = I2 + S3;

[0021] Step 11, the industrial control computer multiplies the integration result I2 by a multiplication coefficient K P5 , to obtain a multiplication result M5 = K P5 ×I2;

[0022] Step 12, the industrial control computer multiplies the multiplication result M4 by a multiplication coefficient K P6 , to obtain a multiplication result M6 = K P6 ×M4;

[0023] Step 13, the industrial control computer performs a subtraction operation on the multiplication result M5 and the multiplication result M6 to obtain a subtraction result S4 = M5 - M6, and transmits S4 to the servo drive in a communication manner, and at the same time returns to Step 1.

[0024] Furthermore, the servo drive has a built-in PID disabling function.

[0025] Furthermore, the multiplication coefficient K P1 is determined by formula (1) as a set value:

[0026]

[0027] where: i is the reduction ratio of the reducer, t is the pitch of the lead screw, and p is the number of pulses generated per revolution of the encoder.

[0028] Furthermore, the multiplication coefficient K P2 is determined by formula (2) as an initial set value:

[0029]

[0030] where: e is the base of the natural logarithm, t is the pitch of the lead screw, V maxis the speed limit value, p is the number of pulses generated per revolution of the encoder, i is the reduction ratio of the speed reducer, and r 0,ml is the maximum value of the lead screw displacement command signal.

[0031] Furthermore, the multiplication coefficient K P3 is determined by formula (3) and used as the initial setting value:

[0032]

[0033] In the formula: e is the base of the natural logarithm, t is the pitch of the lead screw, V max is the speed limit value, p is the number of pulses generated per revolution of the encoder, i is the reduction ratio of the speed reducer, and r 0,ml is the maximum value of the lead screw displacement command signal.

[0034] Furthermore, the multiplication coefficient K P4 is determined by formula (4) and used as the setting value:

[0035]

[0036] In the formula: p is the number of pulses generated per revolution of the encoder.

[0037] Furthermore, the multiplication coefficient K P5 is determined by formula (5) and used as the initial setting value:

[0038]

[0039] In the formula: J is the equivalent inertia of the servo object, e is the base of the natural logarithm, t is the pitch of the lead screw, V max is the speed limit value, p is the number of pulses generated per revolution of the encoder, i is the reduction ratio of the speed reducer, and r 0,ml is the maximum value of the lead screw displacement command signal.

[0040] Furthermore, the multiplication coefficient K P6 is determined by formula (6) and used as the initial setting value:

[0041]

[0042] In the formula: J is the equivalent inertia of the servo object, e is the base of the natural logarithm, t is the pitch of the lead screw, V max is the speed limit value, p is the number of pulses generated per revolution of the encoder, i is the reduction ratio of the speed reducer, and r 0,ml is the maximum value of the lead screw displacement command signal.

[0043] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages:

[0044] (1) The speed-adjustable servo positioning system provided by the present invention has the advantages of fewer control devices, simple interfaces, convenient connection, and low cost.

[0045] (2) The servo positioning system controlled by the digital control method provided by the present invention can achieve the feedback of state variables such as displacement and speed, and the system response speed is adjustable, the positioning accuracy is high, and the characteristics are hard.

[0046] (3) In the digital control method of the speed-adjustable servo positioning system provided by the present invention, the control parameters have calculation formulas for reference. As long as the equivalent inertia of the servo object is identified by the parameter identification method, the control parameters can be quickly debugged according to the formula, saving time. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 is a structural diagram of the speed-adjustable servo positioning system described in the present invention;

[0048] Figure 2 is a structural diagram of the digital control method of the speed-adjustable servo positioning system described in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0049] The technical solution of the invention will be further described below with reference to the accompanying drawings.

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0051] Embodiment 1

[0052] As Figure 1 shown, the speed-adjustable servo positioning system described in the present invention includes an industrial control computer 20, a servo driver 30, and a servo object 40. The industrial control computer 20 is an integrated industrial control computer integrating a host and a display, with touch operation. The servo object 40 integrates a servo motor 41, an encoder 42, a reducer 43, and a lead screw 44. The industrial control computer 20 is cascaded with the servo driver 30 and the servo motor 41 in sequence. One end of the main shaft of the servo motor 41 is connected to the encoder 42, and the other end is connected to the reducer 43. The output shaft of the reducer 43 is connected to the lead screw 44 through a nut, and the encoder 42 is connected to the servo driver 30.

[0053] Among them, the industrial control computer 20 is connected to the servo driver 30 through an Ethernet interface and communicates using the Modbus communication protocol. The servo driver 30 is connected to the servo motor 41 through a PWM output interface. The servo driver 30 has a built-in PID disabling function.

[0054] As Figure 2 shown, the digital control method of the speed-adjustable servo positioning system according to the present invention includes the following steps:

[0055] Step 1, the industrial control computer 20 periodically detects the lead screw 44 displacement signal Rr input by the user therein; and the maximum speed signal V max , and transmits V max to the corresponding address of the servo driver;

[0056] Step 2, the industrial control computer 20 multiplies the lead screw 44 displacement signal R r by the multiplication coefficient K P1 , to obtain a multiplication operation result M1 = K P1 ×R r ;

[0057] The multiplication coefficient K P1 is determined by formula (1) and used as a fixed value:

[0058]

[0059] In the formula: i is the reduction ratio of the reducer 43, t is the pitch of the lead screw 44, and p is the number of pulses generated by the encoder 42 for one revolution.

[0060] Step 3, the industrial control computer 20 performs a subtraction operation on the multiplication operation result M1 and the displacement signal θ transmitted by the servo driver 30 f , to obtain a subtraction operation result S1 = M1 - θ f ;

[0061] Step 4, the industrial control computer 20 performs integration on the subtraction operation result S1 to obtain an integration result I1 = I1 + S1;

[0062] Step 5, the industrial control computer 20 multiplies the integration result I1 by the multiplication coefficient K P2 , to obtain a multiplication operation result M2 = K P2 ×I1;

[0063] The multiplication coefficient K P2 is determined by formula (2) and used as an initial fixed value:

[0064]

[0065] In the formula: e is the base of the natural logarithm, t is the pitch of the lead screw 44, V max is the speed limit value, p is the number of pulses generated by the encoder 42 for one revolution, i is the reduction ratio of the reducer 43, and r 0,ml is the maximum value of the lead screw 44 displacement command signal.

[0066] Step 6, the industrial control computer 20 multiplies the displacement signal θ transmitted by the servo driver 30 f by the multiplication coefficient K P3 , obtaining the multiplication operation result M3 = K P3 ×θ f ;

[0067] The multiplication coefficient K P3 is determined by formula (3) and used as the initial integral value:

[0068]

[0069] where: e is the base of the natural logarithm, t is the pitch of the lead screw 44, V max is the speed limit value, p is the number of pulses generated by the encoder 42 for one revolution, i is the reduction ratio of the speed reducer 43, and r 0,ml is the maximum value of the displacement command signal of the lead screw 44.

[0070] Step 7, the industrial control computer 20 performs a subtraction operation on the multiplication operation result M2 and the multiplication operation result M3, obtaining the subtraction operation result S2 = M2 - M3;

[0071] Step 8, the industrial control computer 20 multiplies the speed signal ω transmitted by the servo driver 30 f by the multiplication coefficient K P4 , obtaining the multiplication operation result M4 = K P4 ×ω f ;

[0072] The multiplication coefficient K P4 is determined by formula 4 and used as the integral value:

[0073]

[0074] where: p is the number of pulses generated by the encoder 42 for one revolution.

[0075] Step 9, the industrial control computer 20 performs a subtraction operation on the subtraction operation result S2 and the multiplication operation result M4, obtaining the subtraction operation result S3 = S2 - M4;

[0076] Step 10, the industrial control computer 20 integrates the subtraction operation result S3, obtaining the integration result I2 = I2 + S3;

[0077] Step 11, the industrial control computer 20 multiplies the integration result I2 by the multiplication coefficient K P5 , obtaining the multiplication operation result M5 = K P5 ×I2;

[0078] The multiplication coefficient K P5 is determined by formula (5) and used as the initial integral value:

[0079]

[0080] Where: J is the equivalent inertia of the servo object 40, e is the base of the natural logarithm, t is the pitch of the lead screw 44, V max is the speed limit value, p is the number of pulses generated per revolution of the encoder 42, i is the reduction ratio of the speed reducer 43, r 0,ml is the maximum value of the displacement command signal of the lead screw 44.

[0081] Step 12, the industrial control computer 20 multiplies the multiplication result M4 by the multiplication coefficient K P6 , to obtain the multiplication result M6 = K P6 ×M4;

[0082] The multiplication coefficient K P6 is determined by formula (6) and used as the initial setting value:

[0083]

[0084] Where: J is the equivalent inertia of the servo object 40, e is the base of the natural logarithm, t is the pitch of the lead screw 44, V max is the speed limit value, p is the number of pulses generated per revolution of the encoder 42, i is the reduction ratio of the speed reducer 43, r 0,ml is the maximum value of the displacement command signal of the lead screw 44.

[0085] Step 13, the industrial control computer 20 performs a subtraction operation on the multiplication result M5 and the multiplication result M6, to obtain the subtraction result S4 = M5 - M6, and transmits S4 to the servo driver 30 by communication, and at the same time returns to Step 1.

[0086] In order to facilitate parameter tuning using the above formulas, it is necessary to further explain the units of the communication output parameters of the servo driver 30. The displacement signal θ f has a dimensionless unit and actually represents the number of pulses. The speed signal ω f has a unit of revolutions per minute. These limitations are adopted by most servo drivers on the market and are universal.

[0087] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A servo positioning system with adjustable speed, characterized in that: The invention comprises an industrial computer (20), a servo driver (30) and a servo object (40), wherein the servo object (40) integrates a servo motor (41), an encoder (42), a reducer (43) and a screw rod (44); the industrial computer (20) is connected in series with the servo driver (30) and the servo motor (41); one end of the main shaft of the servo motor (41) is connected to the encoder (42), and the other end is connected to the reducer (43); the output shaft of the reducer (43) is connected to the screw rod (44), and the encoder (42) is connected to the servo driver (30).

2. The speed-adjustable servo positioning system according to claim 1, characterized in that: The industrial computer (20) is an integrated touch-operated industrial computer that integrates a host and a display. The industrial computer (20) is connected to a servo driver (30) via an Ethernet interface and uses a Modbus communication protocol for communication. The servo driver (30) is connected to a servo motor (41) via a PWM output interface.

3. The digital control method of the speed-adjustable servo positioning system according to claim 1 or 2, characterized in that: The steps include: Step 1: The industrial computer (20) periodically detects the displacement signal R of the screw rod (44) input by the user. r ; and maximum speed signal V max , and V max Transmitted to the corresponding address of the servo driver (30); Step 2: The industrial computer (20) generates a displacement signal R of the screw rod (44) r Multiply by the multiplication factor K P1 , and the multiplication result is M1=K P1 ×R r ; Step 3: The industrial computer (20) calculates the multiplication result M1 and the displacement signal θ transmitted by the servo driver (30). f Perform subtraction operation and obtain the subtraction result S1 = M1-θ f ; Step 4, the industrial computer (20) integrates the subtraction result S1 to obtain an integration result I1=I1+S1; Step 5: The industrial computer (20) multiplies the integral result I1 by the multiplication coefficient K. P2 , and the multiplication result is M2=K P2 ×I1; Step 6: The industrial computer (20) transmits the displacement signal θ to the servo driver (30). f Multiply by the multiplication factor K P3 , and the multiplication result is M3=K P3 ×θ f ; Step 7, the industrial computer (20) performs a subtraction operation on the multiplication operation result M2 and the multiplication operation result M3 to obtain a subtraction operation result S2=M2-M3; Step 8: The industrial computer (20) receives the speed signal ω transmitted from the servo driver (30) f Multiply by the multiplication factor K P4 , and the multiplication result is M4=K P4 ×ω f ; Step 9, the industrial computer (20) performs a subtraction operation on the subtraction operation result S2 and the multiplication operation result M4 to obtain a subtraction operation result S3 = S2 - M4; Step 10, the industrial computer (20) integrates the subtraction result S3 to obtain an integration result I2=I2+S3; Step 11, the industrial computer (20) multiplies the integral result I2 by the multiplication coefficient K P5 , and the multiplication result is M5=K P5 ×I2; Step 12: The industrial computer (20) multiplies the multiplication result M4 by the multiplication coefficient K. P6 , and the multiplication result is M6=K P6 ×M4; Step 13, the industrial computer (20) performs a subtraction operation on the multiplication result M5 and the multiplication result M6 to obtain a subtraction result S4=M5-M6, and transmits S4 to the servo driver (30) in a communication manner, and returns to step 1 at the same time.

4. The digital control method according to claim 3, characterized in that: The servo drive (30) has a built-in PID disable function.

5. The digital control method according to claim 3, characterized in that: Multiplication factor K P1 Determined by formula (1) as the setting value: Wherein: i is the reduction ratio of the reducer (43), t is the pitch of the screw (44), and p is the number of pulses generated by one rotation of the encoder (42).

6. The digital control method according to claim 3, characterized in that: Multiplication factor K P2 Determined by formula (2) as the initial setting value: Where: e is the base of the natural logarithm, t is the pitch of the screw (44), V max is the speed limit value, p is the number of pulses generated by one rotation of the encoder (42), i is the reduction ratio of the reducer (43), r 0,ml is the maximum value of the displacement command signal of the screw rod (44).

7. The digital control method according to claim 3, characterized in that: Multiplication factor K P3 Determined by formula (3) as the initial setting value: Where: e is the base of the natural logarithm, t is the pitch of the screw (44), V max is the speed limit value, p is the number of pulses generated by one rotation of the encoder (42), i is the reduction ratio of the reducer (43), r 0,ml is the maximum value of the displacement command signal of the screw rod (44).

8. The digital control method according to claim 3, characterized in that: Multiplication factor K P4 Determined by formula (4) as the setting value: Where: p is the number of pulses generated by one rotation of the encoder (42).

9. The digital control method according to claim 3, characterized in that: Multiplication factor K P5 Determined by formula (5) as the initial setting value: Where: J is the equivalent inertia of the servo object (40), e is the base of the natural logarithm, t is the pitch of the screw (44), V max is the speed limit value, p is the number of pulses generated by one rotation of the encoder (42), i is the reduction ratio of the reducer (43), r 0,ml is the maximum value of the displacement command signal of the screw rod (44).

10. The digital control method according to claim 3, characterized in that: Multiplication factor K P6 Determined by formula (6) as the initial setting value: Where: J is the equivalent inertia of the servo object (40), e is the base of the natural logarithm, t is the pitch of the screw (44), V max is the speed limit value, p is the number of pulses generated by one rotation of the encoder (42), i is the reduction ratio of the reducer (43), r 0,ml is the maximum value of the displacement command signal of the screw rod (44).

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