Method for calculating position change of torque gun, control method of torque gun, and torque gun

Abstract

The application provides a position change calculation method of a torque gun, comprising: acquiring a first multi-turn number N t1 and a first single-turn position St1 at a first time t1 and a second multi-turn number N t2 and a second single-turn position St2 at a second time t2 within a time interval less than a time of one rotation of a servo motor; judging whether a single-turn absolute value encoder is in a non-jump state, a positive rotation jump state or a reverse rotation jump state; obtaining a corrected turn number N mod at the second time t2 according to the state of the single-turn absolute value encoder at the second time t2 judged in the previous step; and obtaining a position change of the torque gun in the interval time according to the first single-turn position St1 and the second single-turn position St2 and the corrected turn number N mod. The application can quickly and accurately calculate the position change of the rotation of the torque gun. The application also provides a control method of the torque gun and a torque gun using the control method.

Description

Technical Field

[0001] This invention relates to a method for calculating the position change of a torque gun, and in particular to a method for calculating the position change of a torque gun for unlocking a lock in a battery swapping station, a control method for unlocking and locking a torque gun, and a torque gun itself. Background Technology

[0002] In new energy vehicle battery swapping stations, torque guns are frequently used for unlocking and tightening nuts during battery replacement. This process requires speed, position, and torque control. Typically, a servo motor, encoder, and position loop are incorporated into the torque gun to reflect its rotational position. Once the torque gun reaches a set angle value, it stops rotating. However, traditional multi-turn encoders are expensive to produce and, using a servo position loop, have fixed and inflexible functionality. Using a single-turn encoder without a position loop offers higher torque control precision. Therefore, a position change calculation method needs to be designed to accurately determine the torque gun's rotational position. Summary of the Invention

[0003] The purpose of this invention is to provide a method for calculating the position change of a torque gun, which can quickly and accurately calculate the position change of the torque gun's rotation.

[0004] This invention provides a method for calculating the position change of a torque gun. The torque gun includes a servo motor. The servo motor includes a single-turn absolute encoder. The single-turn absolute encoder can read the number of revolutions and the position per revolution. The single-turn absolute encoder has a maximum revolution count value Nmax. A change in the number of revolutions from the maximum count value Nmax to 0 indicates forward rotation, and a change in the number of revolutions from 0 to the maximum count value Nmax indicates reverse rotation. The method for calculating the position change of the torque gun includes:

[0005] Obtain the first multi-turn number Nt1 and the first single-turn position St1 of the single-turn absolute encoder at time t1; obtain the second multi-turn number Nt2 and the second single-turn position St2 at time t2, which is after time t1, where the interval between time t1 and time t2 is less than the time it takes for the servo motor to rotate one revolution; based on the first multi-turn number Nt1 and the second multi-turn number Nt2, determine whether the single-turn absolute encoder is in a state without transition, a state with transition in forward rotation, or a state with transition in reverse rotation at time t2; based on the state of the single-turn absolute encoder determined in the previous step at time t2, correct the second multi-turn number Nt2 at time t2 to obtain the corrected number of turns Nmod at time t2; obtain the position change of the torque gun during the interval time based on the first single-turn position St1, the second single-turn position St2, and the corrected number of turns Nmod.

[0006] The torque gun position change calculation method provided by this invention utilizes the fact that the interval between the first time t1 and the second time t2 is less than the time it takes for the servo motor to rotate one revolution. It collects the number of revolutions at these two times to determine whether the single-revolution absolute encoder is in one of the following states: no transition, a transition during forward rotation, or a transition during reverse rotation. This determines the correction number of revolutions, and finally, the position change of the torque gun over the interval. Using the torque gun position change calculation method provided by this invention, the position change of the torque gun can be calculated accurately and quickly.

[0007] In one illustrative embodiment of a method for calculating the position change of a torque gun, the multi-turn correction parameter X is obtained based on the difference between the second multi-turn number Nt2 and the first multi-turn number Nt1, i.e.: X = Nt2 - Nt1; the state of the single-turn absolute encoder at the second time t2 is determined based on the multi-turn correction parameter X.

[0008] In another illustrative embodiment of a method for calculating the position change of a torque gun, the state of a single-turn absolute encoder at the second time t2 is determined by the following steps based on the multi-turn correction parameter X: if -N max / 2≤X≤N max / 2, then the single-turn absolute encoder is determined to be in a state without a jump at the second time t2; if X<-N max / 2, then the single-turn absolute encoder is determined to be in a forward rotation jump state at the second time t2; and if X>N max / 2, then the single-turn absolute encoder is determined to be in a reverse rotation jump state at the second time t2.

[0009] In another illustrative embodiment of a method for calculating the position change of a torque gun, the number of correction revolutions N mod at the second time t2 is obtained by the following formula:

[0010]

[0011] This invention also provides a control method for a torque gun used to unlock and lock a battery nut. The control method includes: dividing the rotation time of the torque gun during locking and unlocking the battery nut into continuous time intervals, where the interval between each continuous time interval is less than the time it takes for a servo motor to rotate one revolution; obtaining the position change of the torque gun for each continuous time interval using the aforementioned method for calculating the position change of the torque gun; accumulating the position changes of the continuous time intervals to obtain the actual position of the torque gun; and adjusting the speed of the torque gun based on the actual position.

[0012] The torque gun control method provided by the present invention accurately obtains the actual position of the torque gun by measuring the position change of the torque gun within a continuous time interval, so as to accurately control the speed of the torque gun.

[0013] In another illustrative embodiment of the torque gun control method, when the actual position reaches the predetermined rotational position, the speed of the torque gun is reduced to zero.

[0014] In another illustrative embodiment of the torque gun control method, the torque gun is decelerated as the actual position approaches the predetermined rotational position.

[0015] This invention also provides a torque gun for unlocking and locking a battery nut. The torque gun includes a controller, a servo driver, and a servo motor. The servo motor has a single-turn absolute encoder. The torque gun is controlled by the aforementioned unlocking and locking torque gun control method. The torque gun does not have a position loop; it relies on a single-turn absolute encoder to precisely control the speed. The structure is simple and the cost is low. Attached Figure Description

[0016] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Wherein:

[0017] Figure 1 The diagram shows a flowchart of a specific embodiment of the torque gun position change calculation method according to the present invention.

[0018] Figure 2 This is a flowchart illustrating a method for calculating the position change of the torque gun in a forward rotation state without any jump, according to one illustrative embodiment.

[0019] Figure 3 This is a flowchart illustrating a method for calculating the position change of the torque gun in a state where reversal has not occurred, in one illustrative embodiment.

[0020] Figure 4 This is a flowchart illustrating a method for calculating the position change of the torque gun in a state of sudden change during forward rotation, as shown in one illustrative embodiment.

[0021] Figure 5 This is a flowchart illustrating a method for calculating the position change of the torque gun in a state of reversal jump in one illustrative embodiment of the present invention.

[0022] Figure 6 This describes the control method for the torque gun used for unlocking and locking at a battery swapping station. Detailed Implementation

[0023] To provide a clearer understanding of the technical features, objectives, and effects of the invention, specific embodiments of the invention are now described with reference to the accompanying drawings. In the drawings, the same reference numerals indicate components with the same or similar structures but the same function.

[0024] In this document, “illustrative” means “serving as an example, illustration or description”, and any illustration or implementation described herein as “illustrative” should not be construed as a more preferred or advantageous technical solution.

[0025] In this article, "first," "second," etc., are used only to distinguish them from each other, not to indicate their degree of importance.

[0026] The various figures in this document are not strict mathematical and / or geometrical limitations, and also include errors that are understandable to those skilled in the art and permissible in manufacturing or use.

[0027] In this article, the positional change of the torque gun refers to how many revolutions and how many angles the torque gun rotates over a period of time.

[0028] This invention provides a method for calculating the position change of a torque gun. The torque gun includes a controller, a servo driver, and a servo motor. The servo motor includes a single-turn absolute encoder. The single-turn absolute encoder can read the number of revolutions processed by the servo driver and the single-turn position. Here, the number of revolutions refers to the number of revolutions of the single-turn gear in the single-turn absolute encoder. The single-turn position can be represented by an angle.

[0029] A single-turn absolute encoder has a maximum count value Nmax for multiple turns. When the count value Nmax changes from the maximum count value Nmax to 0, it indicates forward rotation and a jump occurs. When the count value Nmax changes from 0 to the maximum count value Nmax, it indicates reverse rotation and a jump occurs.

[0030] Figure 1 The diagram shown is a flowchart of a specific embodiment of the present invention. (See attached diagram.) Figure 1 The method for calculating the position change of the torque gun includes:

[0031] S1: Obtain the number of the first multi-turn Nt1 and the position of the first single turn of the single-turn absolute encoder at time t1;

[0032] S2: Obtain the second multi-revolution number Nt2 located after the first time t1 and the single-revolution position value St2 of the second time t2, where the interval between the first time t1 and the second time t2 is less than the time it takes for the servo motor to rotate one revolution.

[0033] S3: The multi-turn correction parameter X is obtained based on the difference between the second multi-turn number Nt2 and the first multi-turn number Nt1, i.e.: X = Nt2 - Nt. If -Nmax / 2 ≤ X ≤ Nmax / 2, then it is determined that the single-turn absolute encoder is in a state without transition at the second time t2; if X < -Nmax / 2, then it is determined that the single-turn absolute encoder is in a state of transition in the forward direction at the second time t2; and if X > Nmax / 2, then it is determined that the single-turn absolute encoder is in a state of transition in the reverse direction at the second time t2.

[0034] S4: Based on the state of the single-turn absolute encoder determined in the previous step at the second time t2, correct the second multi-turn number Nt2 at the second time t2 to obtain the corrected number of turns Nmod at the second time t2. The corrected number of turns Nmod at the second time t2 is obtained by the following formula:

[0035]

[0036] S5: Based on the number of revolutions N mod, the position of the first single revolution St1, and the position of the second single revolution St2, obtain the position change of the torque gun at the second time t2.

[0037] In such Figure 2-5 In the example shown, 60 degrees is used to represent a single-turn position. In forward rotation, the single-turn position is represented from 1 to 60 degrees. In reverse rotation, the single-turn position is represented from 60 degrees to 1 degree. Using a servo motor with a rated speed of 3000 rpm as an example, this servo motor completes one revolution in 20 milliseconds. Therefore, in this example, the interval between the first time t1 and the second time t2 is within 20 milliseconds. The change in the single-turn code disk of the single-turn absolute encoder from the first time t1 to the second time t2 is within one revolution. The maximum number of revolutions counted, Nmax, is 510.

[0038] Figure 2 This is a flowchart illustrating a method for calculating the position change of the torque gun in a forward rotation state without any jump, according to an illustrative embodiment of the present invention.

[0039] S1: Obtain the number of the first multi-turn Nt1 and the position of the first single turn St1 of the single-turn absolute encoder at the first time t1, Nt1=480, St1=50 degrees (the single-turn absolute encoder obtains 480 turns and 50 degrees).

[0040] S2 obtains the second multi-turn number Nt2 and the second single-turn position St1 of the single-turn absolute encoder at the second time t2, Nt2=481, St2=20 degrees (481 turns 20 degrees).

[0041] S3: Based on the difference between the second number of multiple turns Nt2 and the first number of multiple turns Nt1, the number of multiple turns correction parameter X = Nt2 - Nt1 is obtained, that is: X = 1, which determines that the single-turn absolute encoder is in a state of no jump at the second time t2;

[0042] S4: Based on the state of the single-turn absolute encoder determined in the previous step at the second time t2, correct the second multi-turn number N t2 at the second time t2 to obtain the corrected number of turns N mod = 1 (turns) at the second time t2.

[0043] S5: Based on the corrected number of laps N mod, the position of the first lap St1, and the position of the second lap St2, the relative position of this interval time is calculated through the following process, namely 60 degrees (1 lap) + 20 degrees - 50 degrees = 30 degrees.

[0044] Figure 3 This is a flowchart illustrating a method for calculating the position change of the torque gun in a reversed state without a jump, according to one illustrative embodiment of the present invention.

[0045] S1: Obtain the number of the first multi-turn Nt1 and the position of the first single turn St1 of the single-turn absolute encoder at the first time t1, Nt1=480, St1=20 degrees (the single-turn absolute encoder obtains 480 turns and 20 degrees).

[0046] S2 obtains the second multi-turn number Nt2 and the second single-turn position St2 of the single-turn absolute encoder at the second time t2, Nt2=479, St2=50 degrees (479 turns 50 degrees).

[0047] S3: Based on the difference between the second number of multiple turns Nt2 and the first number of multiple turns Nt1, the number of multiple turns correction parameter X Nt2- Nt1 is obtained, that is: X=- 1, to determine that the single-turn absolute encoder is in a state of no jump at the second time t2;

[0048] S4: Based on the state of the single-turn absolute encoder determined in the previous step at the second time t2, correct the number of the second multi-turn Nt2 at the second time t2, obtaining the corrected number of turns N mod = -1 at the second time t2.

[0049] S5: Based on the number of correction laps N and the position change of a single lap St1-St2, the relative position during this interval is calculated through the following process: -60 degrees (-1 lap) + 50 degrees - 20 degrees = -30 degrees.

[0050] Figure 4 This is a flowchart illustrating a method for calculating the position change of the torque gun in a forward rotation jump state according to an illustrative embodiment of the present invention. In this embodiment, the single-turn absolute encoder has a maximum turn value Nmax of 510.

[0051] S1: Obtain the number of the first multi-turn Nt1 and the position of the first single turn St1 of the single-turn absolute encoder at the first time t1, Nt1=510, St1=50 degrees (the single-turn absolute encoder obtains 510 turns at 50 degrees).

[0052] S2 obtains the second multi-turn number Nt2 and the second single-turn position St1 of the single-turn absolute encoder at the second time t2, Nt2=0, St2=20 degrees (0 turns 20 degrees).

[0053] S3: Based on the difference between the second number of multiple turns Nt2 and the first number of multiple turns Nt1, the multiple turns correction parameter X = Nt2 - Nt1 is obtained, that is: X = -510. According to -510 < -255, it is determined that the single-turn absolute encoder is in the forward rotation and jump state at the second time t2.

[0054] S4: Based on the state of the single-turn absolute encoder determined in the previous step at the second time t2, correct the second multi-turn number N t2 at the second time t2, and obtain the corrected number of turns N mod = X + Y = 1 (turns) at the second time t2.

[0055] S5: Based on the corrected number of laps N mod, the position of the first lap St1, and the position of the second lap St2, the relative position of this interval time is calculated through the following process, namely 60 degrees (1 lap) + 20 degrees - 50 degrees = 30 degrees.

[0056] Figure 5 This is a flowchart illustrating a method for calculating the position change of the torque gun in a state of reversal jump in one illustrative embodiment of the present invention.

[0057] S1: Obtain the first multi-turn number Nt1 and the first single-turn position St1 of the single-turn absolute encoder at the first time t1, Nt1=0, St1=20 degrees (the single-turn absolute encoder gets 0 turns and 20 degrees).

[0058] S2 obtains the second multi-turn number Nt2 and the second single-turn position St1 of the single-turn absolute encoder at the second time t2, Nt2=510, St2=50 degrees (520 turns 50 degrees).

[0059] S3: Based on the difference between the second number of multiple turns Nt2 and the first number of multiple turns Nt1, the number of multiple turns correction parameter X = Nt2 - Nt1 is obtained, that is: X = 510. Based on 510 > 255, it is determined that the single-turn absolute encoder is in the reverse transition state at the second time t2.

[0060] S4: Based on the state of the single-turn absolute encoder determined in the previous step at the second time t2, correct the second multi-turn number N t2 at the second time t2, and obtain the corrected number of turns N mod = X + Y = -1 (turns) at the second time t2.

[0061] S5: Based on the corrected number of laps N mod, the position of the first lap St1, and the position of the second lap St2, the relative position of this interval time is calculated through the following process, namely 60 degrees (-1 lap) + 50 degrees - 20 degrees = -30 degrees.

[0062] Figure 6This describes the control method for the torque gun. The torque gun is used to unlock and lock the battery nut. The torque gun includes a servo motor with a single-turn absolute encoder, but does not have a position loop that directly displays the torque gun's rotational position. When the torque gun's rotational position needs to be positioned during the unlocking or locking of the battery nut, the control method includes:

[0063] S1': Set the predetermined rotation position of the torque gun;

[0064] S2': Divide the rotation time of locking and unlocking the battery nut of the torque gun into continuous time intervals. The interval time of each time interval is less than the time it takes for the servo motor to rotate one revolution. That is, the second moment of the previous time interval is the first moment of the next time interval.

[0065] S3': According to Figure 1 The steps shown (steps S1 to S5) obtain the positional changes for each consecutive time interval.

[0066] S4': Accumulate the position changes of consecutive time intervals to obtain the actual position of the torque gun rotation.

[0067] S5': When the actual position reaches the predetermined rotation position, reduce the speed of the torque gun to zero.

[0068] The torque gun provided by this invention includes a controller, a servo driver, and a servo motor. The servo motor includes a single-turn absolute encoder. The single-turn absolute encoder allows reading the number of revolutions processed by the servo driver and the position per revolution. The torque gun calculates the actual position without setting a position loop. Figure 6 The torque gun controlled by the control method shown relies on a single-turn absolute encoder to precisely control the speed. It has a simple structure and low cost.

[0069] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0070] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention and are not intended to limit the scope of protection of the present invention. All equivalent implementation schemes or modifications made without departing from the spirit of the present invention, such as combinations, divisions or repetitions of features, should be included within the scope of protection of the present invention.

Claims

1. A method for calculating the position change of a torque gun, wherein the torque gun includes a servo motor, the servo motor includes a single-turn absolute encoder, the single-turn absolute encoder can read the number of revolutions and the position of a single revolution, the single-turn absolute encoder has a maximum number of revolutions count value Nmax, the number of revolutions changing from the maximum number of revolutions count value Nmax to 0 indicates a change in forward rotation, the number of revolutions changing from 0 to the maximum number of revolutions count value Nmax indicates a change in reverse rotation, characterized in that... The method for calculating the position change includes: Obtain the first multi-turn number Nt1 and the first single-turn position St1 of the single-turn absolute encoder at the first time t1; Obtain the second number of multiple revolutions Nt2 and the second single revolution position St2 at the second time t2 after the first time t1, wherein the interval between the first time t1 and the second time t2 is less than the time it takes for the servo motor to rotate one revolution. Based on the first number of multiple revolutions Nt1 and the second number of multiple revolutions Nt2, determine whether the single-revolution absolute encoder is in a state of no transition, a state of transition during forward rotation, or a state of transition during reverse rotation at the second time t2; Based on the state of the single-turn absolute encoder determined in the previous step at the second time t2, the second multi-turn number N t2 at the second time t2 is corrected to obtain the corrected number of turns N mod at the second time t2. The positional change of the torque gun during the interval time is obtained based on the first single-turn position St1, the second single-turn position St2, and the modified number of turns N mod.

2. The method for calculating the position change of the torque gun as described in claim 1, characterized in that, Determining whether the single-turn absolute encoder is in a state of no transition, a state of transition during forward rotation, or a state of transition during reverse rotation at the second time t2 is specifically as follows: The multi-lap correction parameter X is obtained based on the difference between the second multi-lap number Nt2 and the first multi-lap number Nt1, that is: X = N t2 - N t1; The state of the single-turn absolute encoder at the second time t2 is determined based on the multi-turn correction parameter X.

3. The method for calculating the position change of the torque gun as described in claim 2, characterized in that, The state of the single-turn absolute encoder at the second time t2 is determined by the following steps based on the multi-turn correction parameter X: If -N max / 2≤X≤N max / 2, then the single-turn absolute encoder is determined to be in the non-jumping state at the second time t2; If X < -N max / 2, then it is determined that the single-turn absolute encoder is in the forward rotation transition state at the second time t2; as well as If X > N max / 2, then it is determined that the single-turn absolute encoder is in the state of inversion jump at the second time t2.

4. The method for calculating the position change of the torque gun as described in claim 3, characterized in that, The number of correction cycles N mod at the second time t2 is obtained by the following formula: 。 5. A method for controlling a torque gun, used for unlocking and locking a battery nut, characterized in that, The control method for the torque gun includes: The rotation time for locking and unlocking the battery nut of the torque gun is divided into continuous time intervals, and the interval of each time interval is less than the time for the servo motor to rotate one revolution. The position change of the torque gun for each consecutive time interval is obtained by the position change calculation method for the torque gun according to any one of claims 1-4; The actual position of the torque gun is obtained by summing up the position changes of the consecutive time intervals. Adjust the speed of the torque gun according to the actual position.

6. The control method for the torque gun according to claim 5, characterized in that, Set the predetermined rotation position of the torque gun; When the actual position reaches the predetermined rotation position, the speed of the torque gun is reduced to zero.

7. The control method for the torque gun according to claim 6, characterized in that, As the actual position approaches the predetermined rotational position, the torque gun is decelerated.

8. A torque gun for unlocking and locking a battery nut, characterized in that, The torque gun includes a controller, a servo driver, and a servo motor, the servo motor having a single-turn absolute encoder, and the torque gun is controlled by the control method of claim 5.

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