A method for position detection of a linear motor encoder in the absence of a magnetic field

Abstract

The application discloses a position detection method of a linear motor encoder in the case of magnetic field loss, which comprises the following steps: alternately arranging S-pole magnets and N-pole magnets on a motor secondary to form a linear magnet array; arranging a plurality of switch Hall sensors to form an array along the movement direction of the annular path on the linear encoder; measuring the vector direction of the magnetic induction intensity of the position where the switch Hall sensor is located, recording the change of the signal collected by a processing chip after the signal is processed, and knowing the electrical angle interval where the secondary is located by reading the encoder data, so that the relative position of the motor primary and the motor secondary on the annular path is detected; in the case of magnetic field loss, the number of switch Hall sensors is increased according to different loss conditions to obtain more detection data; after the data is synthesized, the relative position of the motor primary and the secondary is judged according to the same method, and the positioning of the workpiece position on the annular path is completed.

Description

Technical Field

[0001] This invention belongs to the field of linear motor driven circular path transportation technology, and particularly relates to a position detection method of a linear motor encoder in the absence of a magnetic field. Background Technology

[0002] Circular path transport systems driven by linear motors are widely used in logistics, food, machinery and other industries. With the development of these industries, higher requirements are being placed on the positioning accuracy of workpieces transported on the circular path.

[0003] Patent CN201911242449.8 discloses a cross-belt circular path sorting system, which presents a traditional workpiece positioning scheme. This system comprises several sorting trolleys, a circular conveyor track, a PLC, and photoelectric sensors. The photoelectric sensors are electrically connected to the PLC and are positioned on the circular conveyor track to detect the movement of the sorting trolleys. The photoelectric sensors detect the position of the sorting trolleys, thereby enabling the detection of the position of the workpieces transported on the trolleys. While this method is simple, its positioning accuracy is poor, especially during high-speed operation, where positioning deviations are prone to occur, leading to false detections and missed detections. To prevent this, the circular path must be run slowly, but this affects the operating efficiency of the circular path and prolongs the transportation time.

[0004] Patent CN201922382786.9 discloses a forklift tire conveying system, which uses a barcode scanner-based visual positioning scheme. Compared with photoelectric sensors, the barcode scanner-based visual positioning scheme improves the positioning accuracy and reliability of workpieces in a circular path to a certain extent. It mainly includes a control system, a transfer logistics vehicle, a loading barcode scanner, a gripping barcode scanner, a robotic arm, and a conveying device. The conveying device includes a ground roller conveyor, an ascending conveyor, an overhead roller conveyor, and a descending conveyor connected in sequence. This scheme uses a barcode scanner to scan the vehicle code on the logistics vehicle to detect the workpiece position. However, this scheme has a high assembly cost and increases the complexity of the circular path device, resulting in higher maintenance and replacement costs.

[0005] Meanwhile, the difference between the circular path workpiece positioning system and linear transmission lies in the limitations of the circular path structure. This can lead to a lack of magnets at turns, resulting in data loss and an inability to determine the relative positions of the linear motor stator and mover, causing inaccurate positioning. Therefore, a solution is needed to address these issues.

[0006] It should be noted that the above content falls within the inventor's technical knowledge and does not necessarily constitute prior art. Summary of the Invention

[0007] To address the aforementioned problems, the present invention aims to provide a method for detecting the precise positioning of each workpiece on the circular path when encoder data is missing due to a lack of magnets at the bends of a circular path. This method involves setting a corresponding number of switch Hall sensors based on the polarity and number of the missing magnets, and using a specific algorithm to complete data compensation.

[0008] To achieve the above objectives, this invention proposes a position detection method for a linear motor encoder in the absence of a magnetic field, characterized by the following steps:

[0009] S1: Alternately arrange S-pole magnets and N-pole magnets on the secondary side of the motor to form a linear magnet array. The distance between the centers of adjacent S-pole magnets and N-pole magnets is τ / 2.

[0010] S2: On the linear encoder, several Hall effect sensors are arranged in an array along the circular path movement direction. The length of a single array is s = τ, the distance between any two adjacent Hall effect sensors is τ / n, and the positioning resolution is δ = τ / 2n.

[0011] S3: By measuring the vector direction of the magnetic field strength at the location of the Hall sensor, the high and low levels of the sensor output can be obtained;

[0012] S4: The switch Hall sensors are arranged at a 120° electrical angle on the linear motor encoder, arranged according to one-third of a pole pitch. The output phases of the three switch Hall sensors are 120° apart, and the duty cycle is 50%.

[0013] S5: Three switch Hall sensors are grouped together. The three switch Hall sensors output three Hall signals, which can divide one electrical cycle into six intervals, each interval being 60°.

[0014] S6: Each switch Hall sensor generates a switching signal. After the processing chip collects the signal, it records its changes. A high level is 1 and a low level is 0. Each sector is encoded according to the high and low levels. The signal processing chip can know the electrical angle range of the secondary by reading the encoder data, thereby realizing the position detection of the circular path.

[0015] S7: When the magnets are discontinuous at the bend of the circular path, the signal processing chip cannot obtain complete encoded information and cannot detect the position of the circular path. In this case, the existing data needs to be synthesized to obtain complete data, and then the signal processing chip is used to read the encoded information to finally determine the position of the circular path.

[0016] In one example, in step S1, τ is the pole moment of the periodic spatial magnetic field formed by the linear magnet array, and the primary is located in the magnetic field generated by the linear magnet array.

[0017] In one example, in step S2, n is the number of sensors contained in the switch Hall sensor array, and the Hall elements on a single array are arranged sequentially along the running direction according to the numbers 1, 2, 3...

[0018] In one example, in step S3, the high and low levels of the output vary depending on the model of the switch Hall sensor used.

[0019] In one example, in step S5, the divided electrical cycle interval is the Hall sector, and the output signals of the three switch Hall sensors 1, 2, and 3 are respectively arranged as signals A, B, and C and input to the signal processing chip in sequence.

[0020] In one example, in step S7, when N magnets are missing within the circular path, N+1 sets of switch Hall sensors are needed for data compensation.

[0021] In one example, if a magnet is missing within a circular path, it is necessary to determine the polarity and number of missing magnets.

[0022] In one example, the data compensation method is as follows when the magnet is missing:

[0023] ① Missing S-pole magnet

[0024] When the Hall sensor is of type S:

[0025] If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence, and the second set is numbered 4, 5, and 6 in sequence. The data of Hall effect sensor 4 lags behind Hall effect sensor 1 by the time required for the linear motor to move the distance between the two magnets. The data of Hall effect sensor 1 and Hall effect sensor 4 are ORed together, and the combined data is output as signal A. Similarly, the data of Hall effect sensor 2 and Hall effect sensor 5 are ORed together and combined as signal B, and the data of Hall effect sensor 3 and Hall effect sensor 6 are ORed together and combined as signal C.

[0026] When the switch Hall sensor is type N:

[0027] If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence, and the second set is numbered 4, 5, and 6 in sequence. The data of Hall effect sensor 4 lags behind Hall effect sensor 1 by the time required for the linear motor to move the distance between the two magnets. The data of Hall effect sensor 1 and Hall effect sensor 4 are ANDed together, and the combined data is output as signal A. Similarly, the data of Hall effect sensor 2 and Hall effect sensor 5 are ANDed together and combined as signal B, and the data of Hall effect sensor 3 and Hall effect sensor 6 are ANDed together and combined as signal C.

[0028] ② Missing N-pole magnet

[0029] When the Hall sensor is of type S:

[0030] If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence, and the second set is numbered 4, 5, and 6 in sequence. The data of Hall effect sensor 4 lags behind Hall effect sensor 1 by the time required for the linear motor to move the distance between the two magnets. The data of Hall effect sensor 1 and Hall effect sensor 4 are ANDed together, and the combined data is output as signal A. Similarly, the data of Hall effect sensor 2 and Hall effect sensor 5 are ANDed together and combined as signal B, and the data of Hall effect sensor 3 and Hall effect sensor 6 are ANDed together and combined as signal C.

[0031] When the switch Hall sensor is type N:

[0032] If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence, and the second set is numbered 4, 5, and 6 in sequence. The data of Hall effect sensor 4 lags behind Hall effect sensor 1 by the time required for the linear motor to move the distance between the two magnets. The data of Hall effect sensor 1 and Hall effect sensor 4 are ORed together, and the combined data is output as signal A. Similarly, the data of Hall effect sensor 2 and Hall effect sensor 5 are ORed together and combined as signal B, and the data of Hall effect sensor 3 and Hall effect sensor 6 are ORed together and combined as signal C.

[0033] ③ The SNx pole magnets are missing and the missing magnets are adjacent magnets (meaning that during the operation of the linear motor, the S pole magnet and the N pole magnet are missing in sequence, and x is a positive integer representing the number of times the SN pole magnets are missing).

[0034] The processing method is the same for both S-type and N-type Hall effect sensors:

[0035] When x = 1, there are 2 missing magnets, so 3 sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence; the second set is numbered 4, 5, and 6 in sequence; and the third set is numbered 7, 8, and 9 in sequence. The high and low level values ​​of Hall effect sensors 1, 4, and 7 corresponding to each time sequence need to be connected end to end to form a loop. Adjacent data are ANDed, and then all data are ORed. The data from Hall effect sensors 1, 4, and 7 are combined in this way and output as signal A. Similarly, the data from Hall effect sensors 2, 5, and 8 are combined and output as signal B, and the data from Hall effect sensors 3, 6, and 9 are combined and output as signal C.

[0036] When x = 2, since 4 magnets are missing, 5 sets of Hall effect sensors are needed. Similarly, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, 7, 10, and 13 are connected end to end to form a loop. Adjacent data are ANDed twice, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, 7, 10, and 13 are combined as signal A, the data of Hall effect sensors 2, 5, 8, 11, and 14 are combined as signal B, and the data of Hall effect sensors 3, 6, 9, 12, and 15 are combined as signal C.

[0037] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a ring. Adjacent data are ANDed n / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C.

[0038] ④ The N and S poles are missing and the missing magnets are adjacent magnets (meaning that during the operation of the linear motor, the N pole and S pole are missing in sequence, and x is a positive integer representing the number of times the N and S poles are missing).

[0039] The processing method is the same for both S-type and N-type Hall effect sensors:

[0040] When x = 1, there are 2 missing magnets, so 3 sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence; the second set is numbered 4, 5, and 6 in sequence; and the third set is numbered 7, 8, and 9 in sequence. The high and low level values ​​of Hall effect sensors 1, 4, and 7 corresponding to each time sequence need to be connected end to end to form a loop. Adjacent data are ANDed, and then all data are ORed. The data from Hall effect sensors 1, 4, and 7 are combined in this way and output as signal A. Similarly, the data from Hall effect sensors 2, 5, and 8 are combined and output as signal B, and the data from Hall effect sensors 3, 6, and 9 are combined and output as signal C.

[0041] When x = 2, since 4 magnets are missing, 5 sets of Hall effect sensors are needed. Similarly, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, 7, 10, and 13 are connected end to end to form a loop. Adjacent data are ANDed twice, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, 7, 10, and 13 are combined as signal A, the data of Hall effect sensors 2, 5, 8, 11, and 14 are combined as signal B, and the data of Hall effect sensors 3, 6, 9, 12, and 15 are combined as signal C.

[0042] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a ring. Adjacent data are ANDed n / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C.

[0043] ⑤ The SNSx pole magnets are missing and the missing magnets are adjacent magnets (meaning that during the operation of the linear motor, the S pole, N pole, and S pole are missing in sequence, and x is a positive integer representing the number of times the SNS pole magnets are missing).

[0044] When the Hall sensor is of type S:

[0045] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a ring. Adjacent data are ANDed (n-1) / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C.

[0046] The switch Hall sensor is of type N:

[0047] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a ring. Adjacent data are ANDed (n+1) / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C.

[0048] ⑥ The NSNx pole magnets are missing and the missing magnets are adjacent magnets (meaning that during the operation of the linear motor, the N pole, S pole, N pole are missing in sequence, and x is a positive integer representing the number of times the NSN pole magnets are missing).

[0049] The switch Hall sensor is of type S:

[0050] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. The high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a ring. Adjacent data are ANDed (n+1) / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C. The signal processing chip can determine the relative position of the primary and secondary motors of the linear motor on the ring path by reading the encoded information of signals A, B, and C.

[0051] When the switch Hall sensor is type N:

[0052] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a ring. Adjacent data are ANDed (n-1) / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C. The signal processing chip can determine the relative position of the primary and secondary motors of the linear motor on the ring path by reading the encoded information of signals A, B, and C.

[0053] ⑦ Missing magnets or discontinuities

[0054] In this case, the above six magnet missing methods can be combined to achieve the desired result. The data synthesis adopts the same method as before, except that the number of consecutive magnets required before and after the missing magnet is limited. If the number of missing magnets at a certain point is n, then there must be at least n+2 consecutive magnets before and after the gap, so that the data synthesis can provide more effective data.

[0055] In one example, the linear encoder is spaced apart from the motor primary, and the motor secondary is mounted directly above the linear encoder and the motor primary.

[0056] In one example, the motor secondary winding has S-pole magnets and N-pole magnets arranged at intervals, and the linear encoder is equipped with a switch Hall sensor.

[0057] The position detection method for a linear motor encoder in the absence of a magnetic field proposed in this invention can bring the following beneficial effects:

[0058] 1. Applying Hall effect encoders to position detection on circular paths, relying on the magnetic induction Hall element, can improve the accuracy of position detection compared to photoelectric switches. Compared to vision positioning systems, it reduces the supporting equipment required for circular path positioning, thus saving costs.

[0059] 2. In cases where the lack of magnets at bends on roundabouts leads to data loss, specific calculation methods between data are used, along with the corresponding number of Hall effect sensors to compensate for the missing magnets, to obtain complete and accurate data. This solves the problem of data loss caused by the absence of magnets on non-straight sections of the roundabout path. Attached Figure Description

[0060] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0061] Figure 1 This is a schematic diagram of the relative position structure of the linear motor and the linear encoder in a position detection method for a linear motor encoder under the condition of magnetic field absence, according to the present invention.

[0062] Figure 2 This is a schematic diagram of the linear encoder used in the position detection method of a linear motor encoder under the condition of magnetic field absence according to the present invention.

[0063] Figure 3 This is a schematic diagram of the motor secondary structure of a linear motor encoder for position detection in the absence of a magnetic field, according to the present invention.

[0064] Figure 4 This is a timing diagram of the S-type switch Hall sensors 1, 2, and 3 of the present invention when there is no shortage of magnets.

[0065] Figure 5 This is a schematic diagram showing the voltage levels of Hall sensors 1, 2, and 3 when the S-type switch Hall sensor 1 is between 4N and 5S without a missing magnet, according to the present invention.

[0066] Figure 6 This is a timing diagram of S-type switch Hall sensors 1 and 4 in the absence of the S-pole magnet according to the present invention.

[0067] Figure 7 This is a timing diagram of S-type switch Hall sensors 1 and 4 in the absence of an N-pole magnet, according to the present invention.

[0068] Figure 8 This is a timing diagram of S-type switch Hall sensors 1, 4, and 7 in the absence of SN pole magnets according to the present invention.

[0069] Figure 9 This is a schematic diagram of the voltage levels of S-type switch Hall sensor 1, 4, and 7 when the S-type switch Hall sensor 1 is between 5S and 6N in the absence of the SN pole magnet.

[0070] Figure 10 This is a timing diagram of S-type switch Hall sensors 1, 4, 7, and 10 in the absence of SNS pole magnets according to the present invention.

[0071] Figure 11 This is a schematic diagram showing the voltage levels of S-type switch Hall sensor 1, 4, and 7 when the SNS pole magnet is missing, and the S-type switch Hall sensor 1 is between 5S, 6N, and 7S. Detailed Implementation

[0072] To more clearly illustrate the overall concept of the present invention, a detailed description will be provided below with reference to the accompanying drawings and examples.

[0073] In the description of this invention, it should be understood that the terms "center," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0074] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0075] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0076] In this invention, unless otherwise expressly specified and limited, the first feature "on" or "below" the second feature may be in direct contact with the first and second features, or indirect contact through an intermediate medium. In the description of this specification, references to terms such as "an embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0077] like Figures 1-3 As shown, an embodiment of the present invention proposes a position detection method for a linear motor encoder in the absence of a magnetic field, which includes the following steps:

[0078] S1: S-pole magnets 4 and N-pole magnets 5 are alternately arranged on the secondary winding 3 of the motor to form a linear magnet array. The distance between the centers of adjacent S-pole magnets 4 and N-pole magnets 5 is τ / 2, where τ is the pole moment of the periodic spatial magnetic field formed by the linear magnet array. The primary winding is located in the magnetic field generated by the linear magnet array.

[0079] S2: On the linear encoder, switch Hall sensors 6 are arranged in an array along the circular path movement direction. The length of a single array is s = τ, the distance between any two adjacent switch Hall sensors 6 is τ / n, the positioning resolution is δ = τ / 2n, and n is the number of sensors contained in the switch Hall sensor 6 array. The Hall elements on a single array are arranged sequentially along the running direction according to the numbers 1, 2, 3...

[0080] S3: By measuring the vector direction of the magnetic induction intensity at the location of the Hall sensor 6, the high and low levels of the sensor output can be obtained. The high and low levels of the output vary depending on the model of the Hall sensor 6 used.

[0081] S4: The switch Hall sensor 6 is arranged at a 120° electrical angle on the linear motor encoder, arranged according to one-third of a pole pitch. The output phase of the three switch Hall sensors 6 is 120° out of phase, and the duty cycle is 50%.

[0082] S5: Three switch Hall sensors 6 are grouped together. The three switch Hall sensors 6 output three Hall signals, which can divide one electrical cycle into six intervals, each interval being 60°. The divided electrical cycle intervals are called Hall sectors. The output signals of the three switch Hall sensors 1, 2, and 3 are respectively arranged as signals A, B, and C and input to the signal processing chip in sequence.

[0083] S6: Each switch Hall sensor 6 generates a switching signal. After the processing chip collects the signal, it records its changes. A high level is 1 and a low level is 0. Each sector is encoded according to the high and low levels. The signal processing chip can know the electrical angle range of the secondary by reading the encoder data, thereby realizing the position detection of the circular path.

[0084] S7: When the magnets are discontinuous at the bend of the circular path, the signal processing chip cannot obtain complete encoded information and cannot detect the position of the circular path. In this case, the existing data needs to be checked. After obtaining complete data, the signal processing chip is used to read the encoded information and finally determine the position of the circular path. When N magnets are missing in the circular path, N+1 sets of switch Hall sensors 6 are needed for data compensation.

[0085] Specifically, when a magnet is missing within a circular path, it is necessary to determine the polarity and number of missing magnets.

[0086] Specifically, the linear encoder 1 and the primary motor 2 are arranged alternately, and the secondary motor 3 is mounted directly above the linear encoder 1 and the primary motor 2.

[0087] Specifically, S-pole magnets 4 and N-pole magnets 5 are arranged at intervals in the secondary winding of the motor 3, and a switch Hall sensor 6 is installed in the linear encoder 1.

[0088] Specifically, the switch-type Hall sensor 6 is a latching switch-type Hall sensor. Latching switch-type Hall sensors include S-type and N-type. The S-type switch-type Hall sensor is high-level under the S-pole magnetic field and low-level under the N-pole magnetic field. The N-type switch-type Hall sensor is high-level under the N-pole magnetic field and low-level under the S-pole magnetic field.

[0089] like Figure 4 As shown, without the magnets missing, a complete timing diagram of Hall effect sensors 1, 2, and 3 can be obtained. The thin solid line represents Hall effect sensor 1, the dashed line represents Hall effect sensor 2, and the thick solid line represents Hall effect sensor 3. The pulse data collected by Hall effect sensors 1, 2, and 3 are output as signals A, B, and C, respectively. Except for the start and end positions, all three Hall effect sensors can collect pulse data. Taking the data collected by the three Hall effect sensor elements during the time period when Hall effect sensor 1 is operating between magnets 4 and 5 as an example, ... Figure 5 As shown, the data is encoded in the order of ABC, which corresponds to the six different position states of the Hall encoder in the magnetic field. By reading the encoder value, the relative positions of the primary and secondary motors of the linear motor on the circular path can be determined.

[0090] The following are the data compensation methods for different missing magnet scenarios mentioned above:

[0091] ① Missing S-pole magnet

[0092] When the Hall sensor is of type S:

[0093] If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence, and the second set is numbered 4, 5, and 6 in sequence. The data of Hall effect sensor 4 lags behind Hall effect sensor 1 by the time required for the linear motor to move the distance between the two magnets. The data of Hall effect sensor 1 and Hall effect sensor 4 are ORed together, and the combined data is output as signal A. Similarly, the data of Hall effect sensor 2 and Hall effect sensor 5 are ORed together and combined as signal B, and the data of Hall effect sensor 3 and Hall effect sensor 6 are ORed together and combined as signal C.

[0094] When the switch Hall sensor is type N:

[0095] If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 sequentially, and the second set is numbered 4, 5, and 6 sequentially. The data from Hall effect sensor 4 lags behind Hall effect sensor 1 by the time it takes for the linear motor to move the distance between the two magnets. The data from Hall effect sensor 1 and Hall effect sensor 4 are ANDed together, and the combined data is output as signal A. Similarly, the data from Hall effect sensor 2 and Hall effect sensor 5 are ANDed together and output as signal B, and the data from Hall effect sensor 3 and Hall effect sensor 6 are ANDed together and output as signal C. The processing method is similar to that when the Hall effect sensor is S-shaped, simply replacing the data operation with an AND operation.

[0096] like Figure 6 The diagram shows the timing diagrams for Hall effect sensors 1 and 4 when the Hall effect sensor is S-type and the S-pole magnet is missing. The missing magnet is simulated as number 5. Since one magnet is missing, two sets of Hall effect sensors are needed. During the linear motor's operation, the data detected by the Hall effect sensors in the missing magnet region is in an uncertain state. Figure 4 The data is represented by a thick black solid line. At this time, Hall sensors 1 and 4 may be at a high level or a low level, and their states are unrelated. The data of Hall sensors 1 and 4 are ORed, and the combined data is output as signal A. Similarly, the data of Hall sensors 2 and 5 are ORed, and the combined data is output as signal B. The data of Hall sensors 3 and 6 are ORed, and the combined data is output as signal C. The signal processing chip can determine the relative position of the primary and secondary motors of the linear motor on the circular path by reading the encoded information of signals A, B, and C.

[0097] ② Missing N-pole magnet

[0098] When the Hall sensor is of type S:

[0099] If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence, and the second set is numbered 4, 5, and 6 in sequence. The data from Hall effect sensor 4 lags behind Hall effect sensor 1 by the time required for the linear motor to move the distance between the two magnets. The data from Hall effect sensor 1 and Hall effect sensor 4 are ANDed together, and the combined data is output as signal A. Similarly, the data from Hall effect sensor 2 and Hall effect sensor 5 are ANDed together and combined as signal B, and the data from Hall effect sensor 3 and Hall effect sensor 6 are ANDed together and combined as signal C.

[0100] When the switch Hall sensor is type N:

[0101] If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence, and the second set is numbered 4, 5, and 6 in sequence. The data of Hall effect sensor 4 lags behind Hall effect sensor 1 by the time required for the linear motor to move the distance between the two magnets. The data of Hall effect sensor 1 and Hall effect sensor 4 are ORed together, and the combined data is output as signal A. Similarly, the data of Hall effect sensor 2 and Hall effect sensor 5 are ORed together and combined as signal B, and the data of Hall effect sensor 3 and Hall effect sensor 6 are ORed together and combined as signal C.

[0102] like Figure 7 The diagram shows the timing of the high and low levels of Hall effect sensors 1 and 4 when the Hall effect sensor is S-type and the N-pole magnet is missing. The missing magnet is number 6. Since one magnet is missing, two sets of Hall effect sensors are needed. Similar to the case of missing one S-pole magnet, the levels of Hall effect sensors 1 and 4 are in an uncertain state within the missing magnet range, represented by a thick black line in the diagram. Their states are unrelated. The data from Hall effect sensors 1 and 4 are ANDed, and the resulting data is output as signal A. Similarly, the data from Hall effect sensors 2 and 5 are ANDed, and the resulting data is output as signal B. The data from Hall effect sensors 3 and 6 are ANDed, and the resulting data is output as signal C. The signal processing chip can determine the relative positions of the primary and secondary motors on the circular path by reading the encoded information of signals A, B, and C.

[0103] ③ The SNx pole magnets are missing and the missing magnets are adjacent magnets (meaning that during the operation of the linear motor, the S pole magnet and the N pole magnet are missing in sequence, and x is a positive integer representing the number of times the SN pole magnets are missing).

[0104] When x = 1, there are 2 missing magnets, so 3 sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence; the second set is numbered 4, 5, and 6 in sequence; and the third set is numbered 7, 8, and 9 in sequence. The high and low level values ​​of Hall effect sensors 1, 4, and 7 corresponding to each time sequence need to be connected end to end to form a loop. Adjacent data are ANDed, and then all data are ORed. The data from Hall effect sensors 1, 4, and 7 are combined in this way and output as signal A. Similarly, the data from Hall effect sensors 2, 5, and 8 are combined and output as signal B, and the data from Hall effect sensors 3, 6, and 9 are combined and output as signal C.

[0105] When x = 2, since 4 magnets are missing, 5 sets of Hall effect sensors are needed. Similarly, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, 7, 10, and 13 are connected end to end to form a loop. Adjacent data are ANDed twice, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, 7, 10, and 13 are combined as signal A, the data of Hall effect sensors 2, 5, 8, 11, and 14 are combined as signal B, and the data of Hall effect sensors 3, 6, 9, 12, and 15 are combined as signal C.

[0106] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a ring. Adjacent data are ANDed n / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C.

[0107] In the above description, the data after each AND operation must be sorted according to the rule that both 1s and 0s are consecutive;

[0108] In the above cases, regardless of whether the switch Hall sensor is type S or type N, the above method is used.

[0109] Figure 8-9 As shown, the Hall effect sensor is S-type. The simulated missing magnets in the diagram are numbers 5 and 6. Since two magnets are missing, three sets of Hall effect sensors are needed. The high and low levels of Hall effect sensors 1, 4, and 7 during the missing 5S and 6N electrical cycles are recorded. Figure 9 In the process, the data is concatenated end-to-end to form a loop. Adjacent data are ANDed together, and then all data are ORed together to obtain the level values ​​corresponding to times ① and ②. Similarly, the level values ​​corresponding to times ③, ④, ⑤, and ⑥ can be obtained. Finally, the complete output signal A synthesized by switch Hall sensors 1, 4, and 7 can be obtained. The same method is used to obtain the complete output signal B synthesized by switch Hall sensors 2, 5, and 8, and the complete output signal C synthesized by switch Hall sensors 3, 6, and 9. The signal processing chip can determine the relative position of the primary and secondary motors of the linear motor on the loop path by reading the encoded information of signals A, B, and C.

[0110] ④ The N and S poles are missing and the missing magnets are adjacent magnets (meaning that during the operation of the linear motor, the N pole and S pole are missing in sequence, and x is a positive integer representing the number of times the N and S poles are missing).

[0111] When x = 1, there are 2 missing magnets, so 3 sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence; the second set is numbered 4, 5, and 6 in sequence; and the third set is numbered 7, 8, and 9 in sequence. The high and low level values ​​of Hall effect sensors 1, 4, and 7 corresponding to each time sequence need to be connected end to end to form a loop. Adjacent data are ANDed, and then all data are ORed. The data from Hall effect sensors 1, 4, and 7 are combined in this way and output as signal A. Similarly, the data from Hall effect sensors 2, 5, and 8 are combined and output as signal B, and the data from Hall effect sensors 3, 6, and 9 are combined and output as signal C.

[0112] When x = 2, since 4 magnets are missing, 5 sets of Hall effect sensors are needed. Similarly, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, 7, 10, and 13 are connected end to end to form a loop. Adjacent data are ANDed twice, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, 7, 10, and 13 are combined as signal A, the data of Hall effect sensors 2, 5, 8, 11, and 14 are combined as signal B, and the data of Hall effect sensors 3, 6, 9, 12, and 15 are combined as signal C.

[0113] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a ring. Adjacent data are ANDed n / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C.

[0114] In the above description, the data after each AND operation must be sorted according to the rule that both 1s and 0s are consecutive;

[0115] In the above cases, regardless of whether the switch Hall sensor is type S or type N, the above method is used.

[0116] ⑤ The SNSx pole magnets are missing and the missing magnets are adjacent magnets (meaning that during the operation of the linear motor, the S pole, N pole, and S pole are missing in sequence, and x is a positive integer representing the number of times the SNS pole magnets are missing).

[0117] When the Hall sensor is of type S:

[0118] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a ring. Adjacent data are ANDed (n-1) / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C.

[0119] The switch Hall sensor is of type N:

[0120] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a ring. Adjacent data are ANDed (n+1) / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C.

[0121] like Figure 10-11 As shown, the Hall effect sensor is S-type. The simulated missing magnets are numbers 5, 6, and 7. Since 3 magnets are missing, 4 sets of Hall effect sensors are needed. The high and low levels of Hall effect sensors 1, 4, and 7 during the missing 5S, 6N, and 7S time periods are recorded. Figure 11 In the process of connecting the data end to end to form a loop, performing AND operation on adjacent data, and then ORing all data, we can obtain the level values ​​corresponding to times ①②③. Similarly, we can obtain the level values ​​corresponding to times ④⑤⑥⑦⑧⑨. Finally, we can obtain the complete output signal A synthesized by the Hall sensors 1, 4, 7, and 10. Using the same method, we can obtain the complete output signal B synthesized by the Hall sensors 2, 5, 8, and 11, and the complete output signal C synthesized by the Hall sensors 3, 6, 9, and 12. The signal processing chip can determine the relative positions of the primary and secondary motors of the linear motor on the loop path by reading the encoded information of signals A, B, and C.

[0122] In the above description, regardless of whether the Hall sensor is type S or type N, the data after each AND operation must be sorted according to the rule that both 1s and 0s are consecutive.

[0123] ⑥ The NSNx pole magnets are missing and the missing magnets are adjacent magnets (meaning that during the operation of the linear motor, the N pole, S pole, N pole are missing in sequence, and x is a positive integer representing the number of times the NSN pole magnets are missing).

[0124] The switch Hall sensor is of type S:

[0125] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. The high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a loop. Adjacent data are ANDed (n+1) / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A for output, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B for output, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C for output. The signal processing chip can determine the relative position of the primary and secondary motors of the linear motor on the loop path by reading the encoded information of signals A, B, and C.

[0126] When the switch Hall sensor is type N:

[0127] When x = n, it means that n magnets are missing, so n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 3n+1 are connected end to end to form a ring. Adjacent data are ANDed (n-1) / 2 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 3n+1 are combined as signal A for output, the data of Hall effect sensors 2, 5, ..., 3n+2 are combined as signal B for output, and the data of Hall effect sensors 3, 6, ..., 3n+3 are combined as signal C for output. The signal processing chip can determine the relative position of the primary and secondary motors of the linear motor on the ring path by reading the encoded information of signals A, B, and C.

[0128] In the above description, regardless of whether the switch Hall sensor is of type S or type N, the data after each AND operation must be sorted according to the rule that both 1 and 0 are consecutive.

[0129] ⑦ Missing magnets or discontinuities

[0130] In this case, the above six magnet missing methods can be combined to achieve the desired result. The data synthesis adopts the same method as before, except that the number of consecutive magnets required before and after the missing magnet is limited. If the number of missing magnets at a certain point is n, then there must be at least n+2 consecutive magnets before and after the gap, so that the data synthesis can provide more effective data.

[0131] Working principle: S-pole magnets and N-pole magnets are alternately arranged at the bottom of the motor secondary winding on the circular path, causing it to drive the workpiece to move horizontally between the linear encoder and the motor primary winding. The switching signals generated by the Hall effect sensors arranged at the bottom of the linear encoder are collected and recorded by the processing chip to realize the position detection of the circular path. When the S-pole magnets and N-pole magnets at the turning points of the circular path are missing individually, continuously, or discontinuously, a specific number of Hall effect sensors are added to the linear encoder in conjunction with a specific algorithm to complete the data compensation, obtain complete and accurate data, and solve the data loss problem caused by the absence of magnets on the non-straight sections of the circular path.

[0132] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to interchangeably. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0133] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for position detection of a linear motor encoder in the absence of a magnetic field, characterized in that, Includes the following steps: S1: S-pole magnets and N-pole magnets are alternately arranged on the secondary side of the motor to form a linear magnet array. The distance between the centers of adjacent S-pole magnets and N-pole magnets is τ / 2. Wherein, τ is the pole pitch of the periodic spatial magnetic field formed by the linear magnet array, and the primary side of the motor is located in the magnetic field generated by the linear magnet array. S2: On the linear encoder, a switch Hall sensor array is arranged along the direction of motion of the circular path, and the length of a single array is s = τ; S3: The high and low levels of the sensor output are obtained by measuring the vector direction of the magnetic field strength at the location of the Hall sensor. S4: The switch Hall sensors are arranged at a 120° electrical angle on the linear motor encoder, with one-third of a pole pitch. The output phases of the three switch Hall sensors differ by 120°, and the duty cycle is 50%. S5: Three switch Hall sensors are grouped together. The three switch Hall sensors output three Hall signals, dividing one electrical cycle into six intervals, each interval being 60°. S6: Each switch Hall sensor generates a switching signal. After the processing chip collects the signal, it records its changes. A high level is 1 and a low level is 0. Each sector is encoded according to the high and low levels. The signal processing chip can know the electrical angle range of the secondary by reading the encoder data, thereby realizing the position detection of the circular path. S7: When magnets are discontinuous at the bend of the circular path, the signal processing chip cannot obtain complete encoded information and cannot detect the position of the circular path by obtaining the polarity and number of missing magnets. When N magnets are missing in the circular path, N+1 sets of switch Hall sensors are needed for data compensation. Logical operations are performed on the output levels of the N+1 sets of switch Hall sensors to obtain the A, B, and C three-phase encoded information after data synthesis. Then, the signal processing chip reads the encoded information to finally determine the position of the circular path.

2. The method for position detection of a linear motor encoder in the absence of a magnetic field according to claim 1, characterized in that, In step S3, the output high and low levels vary depending on the model of the Hall sensor used.

3. The method for position detection of a linear motor encoder in the absence of a magnetic field according to claim 1, characterized in that, In step S5, the divided electrical cycle interval is the Hall sector, and the output signals of the three switch Hall sensors 1, 2, and 3 are respectively arranged as signals A, B, and C and input to the signal processing chip in sequence.

4. The position detection method of a linear motor encoder under magnetic field absence as described in claim 1, characterized in that, In the case of missing magnets, the data compensation method is as follows: ① Missing S-pole magnet When the Hall sensor is of type S: If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence, and the second set is numbered 4, 5, and 6 in sequence. The data of Hall effect sensor 4 lags behind Hall effect sensor 1 by the time required for the linear motor to move the distance between the two magnets. The data of Hall effect sensor 1 and Hall effect sensor 4 are ORed together, and the combined data is output as signal A. Similarly, the data of Hall effect sensor 2 and Hall effect sensor 5 are ORed together and combined as signal B, and the data of Hall effect sensor 3 and Hall effect sensor 6 are ORed together and combined as signal C. When the switch Hall sensor is type N: If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence, and the second set is numbered 4, 5, and 6 in sequence. The data of Hall effect sensor 4 lags behind Hall effect sensor 1 by the time required for the linear motor to move the distance between the two magnets. The data of Hall effect sensor 1 and Hall effect sensor 4 are ANDed together, and the combined data is output as signal A. Similarly, the data of Hall effect sensor 2 and Hall effect sensor 5 are ANDed together and combined as signal B, and the data of Hall effect sensor 3 and Hall effect sensor 6 are ANDed together and combined as signal C. ② Missing N-pole magnet When the Hall sensor is of type S: If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence, and the second set is numbered 4, 5, and 6 in sequence. The data of Hall effect sensor 4 lags behind Hall effect sensor 1 by the time required for the linear motor to move the distance between the two magnets. The data of Hall effect sensor 1 and Hall effect sensor 4 are ANDed together, and the combined data is output as signal A. Similarly, the data of Hall effect sensor 2 and Hall effect sensor 5 are ANDed together and combined as signal B, and the data of Hall effect sensor 3 and Hall effect sensor 6 are ANDed together and combined as signal C. When the switch Hall sensor is type N: If one magnet is missing, two sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence, and the second set is numbered 4, 5, and 6 in sequence. The data of Hall effect sensor 4 lags behind Hall effect sensor 1 by the time required for the linear motor to move the distance between the two magnets. The data of Hall effect sensor 1 and Hall effect sensor 4 are ORed together, and the combined data is output as signal A. Similarly, the data of Hall effect sensor 2 and Hall effect sensor 5 are ORed together and combined as signal B, and the data of Hall effect sensor 3 and Hall effect sensor 6 are ORed together and combined as signal C. ③ The absence of SNx pole magnets and the missing magnets being adjacent magnets indicates that during the operation of the linear motor, the S pole magnet and the N pole magnet are missing in sequence, where x is a positive integer representing the number of times the SN pole magnet is missing. The processing method is the same for both S-type and N-type Hall effect sensors: When x=1, there are 2 missing magnets, so 3 sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence; the second set is numbered 4, 5, and 6 in sequence; and the third set is numbered 7, 8, and 9 in sequence. The high and low level values ​​of Hall effect sensors 1, 4, and 7 corresponding to each time sequence need to be connected end to end to form a loop. Adjacent data are ANDed, and then all AND results are ORed. The data from Hall effect sensors 1, 4, and 7 are combined in this way and output as signal A. Similarly, the data from Hall effect sensors 2, 5, and 8 are combined and output as signal B, and the data from Hall effect sensors 3, 6, and 9 are combined and output as signal C. When x=2, since 4 magnets are missing, 5 sets of Hall effect sensors are needed. Similarly, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, 7, 10, and 13 are connected end to end to form a loop. Adjacent data are ANDed twice, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, 7, 10, and 13 are combined as signal A, the data of Hall effect sensors 2, 5, 8, 11, and 14 are combined as signal B, and the data of Hall effect sensors 3, 6, 9, 12, and 15 are combined as signal C. When x=n, it means that 2n magnets are missing, so 2n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 6n+1 are connected end to end to form a ring. Adjacent data are ANDed n times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 6n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 6n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 6n+3 are combined as signal C. ④ The absence of NSx pole magnets and the missing magnets being adjacent magnets indicates that during the operation of the linear motor, the N pole and S pole are missing in sequence. x is a positive integer, representing the number of times the NS pole magnets are missing. The processing method is the same for both S-type and N-type Hall effect sensors: When x=1, there are 2 missing magnets, so 3 sets of Hall effect sensors are needed. The first set of Hall effect sensors is numbered 1, 2, and 3 in sequence; the second set is numbered 4, 5, and 6 in sequence; and the third set is numbered 7, 8, and 9 in sequence. The high and low level values ​​of Hall effect sensors 1, 4, and 7 corresponding to each time sequence need to be connected end to end to form a loop. Adjacent data are ANDed, and then all AND results are ORed. The data from Hall effect sensors 1, 4, and 7 are combined in this way and output as signal A. Similarly, the data from Hall effect sensors 2, 5, and 8 are combined and output as signal B, and the data from Hall effect sensors 3, 6, and 9 are combined and output as signal C. When x=2, since 4 magnets are missing, 5 sets of Hall effect sensors are needed. Similarly, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, 7, 10, and 13 are connected end to end to form a loop. Adjacent data are ANDed twice, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, 7, 10, and 13 are combined as signal A, the data of Hall effect sensors 2, 5, 8, 11, and 14 are combined as signal B, and the data of Hall effect sensors 3, 6, 9, 12, and 15 are combined as signal C. When x=n, it means that 2n magnets are missing, so 2n+1 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 6n+1 are connected end to end to form a ring. Adjacent data are ANDed n times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 6n+1 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 6n+2 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 6n+3 are combined as signal C. ⑤ The absence of SNSx pole magnets and the missing magnets are adjacent magnets, indicating that during the operation of the linear motor, the S pole, N pole, and S pole are missing in sequence. x is a positive integer, representing the number of times the SNS pole magnets are missing. When the Hall sensor is of type S: When x=n, it means that 2n+1 magnets are missing, so 2n+2 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 6n+4 are connected end to end to form a ring. Adjacent data are ANDed n times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 6n+4 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 6n+5 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 6n+6 are combined as signal C. The switch Hall sensor is of type N: When x=n, it means that 2n+1 magnets are missing, so 2n+2 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 6n+4 are connected end to end to form a ring. Adjacent data are ANDed n+1 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 6n+4 are combined as signal A, the data of Hall effect sensors 2, 5, ..., 6n+5 are combined as signal B, and the data of Hall effect sensors 3, 6, ..., 6n+6 are combined as signal C. ⑥ The NSNx pole magnet is missing and the missing magnet is an adjacent magnet. This means that during the operation of the linear motor, the N pole, S pole and N pole are missing in sequence. x is a positive integer, which represents the number of times the NSN pole magnet is missing. The switch Hall sensor is of type S: When x=n, it means that 2n+1 magnets are missing, so 2n+2 sets of Hall effect sensors are needed. The high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 6n+4 are connected end to end to form a ring. Adjacent data are ANDed n+1 times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 6n+4 are combined as signal A for output, the data of Hall effect sensors 2, 5, ..., 6n+5 are combined as signal B for output, and the data of Hall effect sensors 3, 6, ..., 6n+6 are combined as signal C for output. The signal processing chip can determine the relative position of the primary and secondary motors of the linear motor on the ring path by reading the encoded information of signals A, B, and C. When the switch Hall sensor is type N: When x=n, it means that 2n+1 magnets are missing, so 2n+2 sets of Hall effect sensors are needed. That is, the high and low level values ​​corresponding to each timing sequence of Hall effect sensors 1, 4, ..., 6n+4 are connected end to end to form a ring. Adjacent data are ANDed n times, and then all data are ORed. Finally, the data of Hall effect sensors 1, 4, ..., 6n+4 are combined as signal A for output, the data of Hall effect sensors 2, 5, ..., 6n+5 are combined as signal B for output, and the data of Hall effect sensors 3, 6, ..., 6n+6 are combined as signal C for output. The signal processing chip can determine the relative position of the primary and secondary motors of the linear motor on the ring path by reading the encoded information of signals A, B, and C. ⑦ Missing magnets are discontinuous In this case, the above six magnet missing methods are combined; the data synthesis adopts the same method as above, only limiting the number of consecutive magnets required before and after the missing magnet. If the number of missing magnets is n, then there must be at least n+2 consecutive magnets before and after the gap, so that the data synthesis provides more effective data.

5. The method for position detection of a linear motor encoder in the absence of a magnetic field according to claim 1, characterized in that, The linear encoder and the primary motor are arranged at intervals, and the secondary motor is mounted directly above the linear encoder and the primary motor.

Images