System for realizing positive and negative 360-degree operation of joint of collaborative robot based on double encoders

Abstract

The invention relates to a system for achieving positive and negative 360-degree operation of a joint of a collaborative robot based on double encoders, and belongs to the field of collaborative robots. The system comprises a double-encoder framework which comprises a motor side magnetic absolute value encoder and a speed reducer side magnetic absolute value encoder; the first encoder circuit board processes an encoder signal of the motor side magnetic absolute value encoder; the second encoder circuit board processes an encoder signal of the speed reducer side magnetic absolute value encoder; the main control circuit board is used for carrying out zero calibration on the motor side magnetic absolute value encoder and the speed reducer side magnetic absolute value encoder, and a processor of the main control circuit board adopts a multi-circle value storage strategy to periodically record the actual position of the joint or the speed reducer side encoder value when the collaborative robot normally operates; and the main control circuit board calculates a current actual multi-circle count value, and further calculates the actual position of the joint of the collaborative robot. The system provided by the invention can thoroughly eliminate battery dependence and has the characteristic of high reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of collaborative robots, and in particular to a system for enabling collaborative robot joints to operate in positive and negative 360 ​​degrees based on dual encoders. Background Art

[0002] Existing industrial collaborative robot joints generally use a "single encoder + battery power solution" to achieve ±360° multi-turn position detection. The encoder relies on an internal battery (sometimes a lithium battery) to maintain the multi-turn count value during power outages, ensuring that the zero point is not lost after restarting.

[0003] However, the prior art has the following defects and deficiencies:

[0004] 1. High maintenance cost: The battery life is limited (0.5-1.5 years), and it needs to be replaced frequently and relies on manual on-site service;

[0005] 2. Reliability risk:

[0006] (1) Vibration causes poor battery contact, resulting in loss of multiple turn values ​​(zero point loss);

[0007] (2) Lithium batteries pose a fire / smoke safety hazard;

[0008] 3. Operation and maintenance burden: The battery status needs to be monitored regularly, which increases the complexity of system management. Summary of the Invention

[0009] The object of the present invention is to solve at least one of the technical drawbacks.

[0010] To this end, the purpose of the present invention is to propose a system based on dual encoders to achieve 360-degree operation of collaborative robot joints, which can completely eliminate battery dependence and has the characteristics of high reliability.

[0011] To achieve the above objectives, an embodiment of the present invention provides a system for realizing positive and negative 360-degree movement of collaborative robot joints based on dual encoders, comprising:

[0012] Dual encoder architecture, main control circuit board, first encoder circuit board, second encoder circuit board, reducer and motor, wherein,

[0013] The dual-encoder architecture includes: a motor-side magnetic absolute encoder and a reducer-side magnetic absolute encoder, wherein the motor-side magnetic absolute encoder is installed on the output shaft of the motor, and the reducer-side magnetic absolute encoder is directly connected to the output shaft of the reducer;

[0014] The first encoder circuit board is connected to the motor side magnetic absolute value encoder and is used to process the encoder signal of the motor side magnetic absolute value encoder;

[0015] The second encoder circuit board is connected to the reducer side magnetic absolute encoder and is used to process the encoder signal of the reducer side magnetic absolute encoder;

[0016] The main control circuit board integrates a processor, a non-volatile storage module and a communication module. The main control circuit board is used to calibrate the zero point of the motor side magnetic absolute encoder and the reducer side magnetic absolute encoder. When the collaborative robot is operating normally, the processor of the main control circuit board adopts a multi-turn value storage strategy to periodically record the actual position of the joint or the reducer side encoder value; each time the equipment is powered on, the main control circuit board reads the offset value of the motor side and reducer side encoder relative to the zero point, and combines the historical records saved in the non-volatile storage module to calculate the current actual multi-turn count value, and then calculates the actual position of the collaborative robot joint.

[0017] Furthermore, the resolution of the motor-side magnetic absolute encoder is greater than or equal to 17 bits.

[0018] Furthermore, the encoder signal of the motor-side magnetic absolute encoder and the encoder signal of the reducer-side magnetic absolute encoder support independent or combined communication transmission.

[0019] Furthermore, the encoder signal of the motor-side magnetic absolute encoder and the encoder signal of the reducer-side magnetic absolute encoder are combined and transmitted via a differential signal line.

[0020] Furthermore, the motor side magnetic absolute value encoder and the reducer side magnetic absolute value encoder are installed on different sides or on the same side.

[0021] Furthermore, when the different-side installation method is adopted, the motor-side magnetic absolute value encoder and the reducer-side magnetic absolute value encoder are respectively installed on independent circuit boards;

[0022] When the same-side installation method is adopted, the motor-side magnetic absolute value encoder and the reducer-side magnetic absolute value encoder are installed on a shared circuit board.

[0023] Furthermore, the main control circuit board is used to calibrate the motor side magnetic absolute value encoder and the reducer side magnetic absolute value encoder for zero point, including: synchronous acquisition at the mechanical zero point position, and the current moment of the motor side encoder absolute position value P Motor_Zero The absolute position value P of the encoder on the reducer side Reducer_Zero , recorded and stored in the non-volatile storage module as a reference value for subsequent dual encoder system calibration.

[0024] Furthermore, the main control circuit board adopts one of the following two multi-turn value storage strategies to periodically record the actual position of the joint or the encoder value on the reducer side. The two multi-turn value storage strategies include:

[0025] (1) Timing storage mode: stores the current reducer side encoder value P in a fixed period Reducer_Current ;

[0026] (2) Event trigger storage mode: When the encoder position change ΔP on the reducer side Reducer When the set threshold is exceeded, the encoder value on the reducer side is recorded immediately.

[0027] Furthermore, the actual multi-turn count value N is calculated. 多圈 ,include:

[0028]

[0029] Where i is the reduction ratio, R is the single-turn resolution of the reducer side; P Reducer_Current is the encoder value of the current reducer side; P Reducer_Store The last valid encoder value on the reducer side; P Reducer_Zero It is the absolute position value of the encoder on the reducer side.

[0030] Furthermore, the main control circuit board calculates the actual position P of the collaborative robot joint 全局

[0031] P 全局 =(N 多圈 ×R')+(P Motor_Current -P motor_zero )

[0032] Among them, R' is the single-turn resolution of the motor side encoder, N 多圈 is the multi-turn count value, P motor_current is the current motor side encoder reading, P Motor_Zero It is the absolute position value of the motor side encoder.

[0033] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0034] The dual-encoder system of the present invention, which enables 360-degree rotation of collaborative robot joints, employs dual encoders to implement a ±360° algorithm. This dual encoder, combined with the reducer-side encoder values ​​stored in a non-volatile memory module, maintains the correct joint position even after power failure, avoiding the issue of zero point loss.

[0035] 1. Completely eliminate battery dependence: avoid replacement costs, poor contact and safety risks.

[0036] 2. High reliability: Dual encoder redundant design improves position detection fault tolerance; non-volatile storage ensures zero data loss after power failure.

[0037] 3. Improved accuracy: Collision detection (±0.5 turn threshold) and self-calibration (±0.05° threshold) mechanisms ensure long-term accuracy.

[0038] 4. Maintenance costs reduced by 40%+: battery replacement and related labor services are eliminated.

[0039] 5. Industrial adaptability: IP67 protection + anti-oil design, service life increased to ≥5 years.

[0040] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of the embodiments with reference to the accompanying drawings, in which:

[0042] Figure 1 This is a structural diagram of a system for realizing positive and negative 360-degree movement of collaborative robot joints based on dual encoders according to an embodiment of the present invention;

[0043] Figure 2a and Figure 2b Schematic diagram of a motor-side encoder and a reducer-side encoder according to an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The following describes embodiments of the present invention in detail, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and are not to be construed as limiting the present invention.

[0045] The present invention proposes a system for achieving 360-degree rotation of collaborative robot joints based on dual encoders. The system proposes a battery-free dual encoder system architecture (motor-side + reducer-side encoder + non-volatile storage), dual encoder installation methods (same-side / opposite-side) and communication multiplexing methods, a multi-turn value storage strategy and conflict detection / self-recovery algorithm, and a dual encoder-based zero point calibration and abnormal switching method. The following describes in detail the system for achieving 360-degree rotation of collaborative robot joints based on dual encoders, in conjunction with specific embodiments.

[0046] The dual-encoder system of the present invention, which enables 360-degree rotation of collaborative robot joints, employs dual encoders to implement a ±360° algorithm. This dual encoder, combined with the reducer-side encoder values ​​stored in a non-volatile memory module, maintains the correct joint position even after power failure, avoiding the issue of zero point loss.

[0047] like Figure 1 As shown, the system of the embodiment of the present invention that realizes the positive and negative 360-degree operation of the collaborative robot joints based on dual encoders includes: a dual encoder architecture, a main control circuit board 101, a first encoder circuit board 108, a second encoder circuit board 107, a reducer and a motor.

[0048] Specifically, the dual encoder architecture includes: a motor-side magnetic absolute encoder 109 and a reducer-side magnetic absolute encoder 110. The motor-side magnetic absolute encoder 109 is mounted on the output shaft of the motor, and the reducer-side magnetic absolute encoder 110 is directly connected to the output shaft of the reducer.

[0049] In an embodiment of the present invention, the resolution of the motor-side magnetic absolute encoder 109 is greater than or equal to 17 bits (≥17-bit resolution), and is installed on the motor output shaft.

[0050] The motor side magnetic absolute value encoder 109 and the reducer side magnetic absolute value encoder 110 are installed on different sides or on the same side.

[0051] (1) When the opposite-side installation method is adopted, the motor-side magnetic absolute value encoder 109 and the reducer-side magnetic absolute value encoder 110 are respectively installed on independent circuit boards.

[0052] (2) When the same-side installation method is adopted, the motor-side magnetic absolute value encoder 109 and the reducer-side magnetic absolute value encoder 110 are installed on a shared circuit board.

[0053] The encoder circuit board of the present invention includes a first encoder circuit board 108 and a second first encoder circuit board 108, which are used to process dual-path encoder signals and support independent or combined communication transmission. Specifically, the first encoder circuit board 108 is connected to the motor-side magnetic absolute encoder 109 and processes the encoder signals from the motor-side magnetic absolute encoder 109. The second encoder circuit board 107 is connected to the reducer-side magnetic absolute encoder 110 and processes the encoder signals from the reducer-side magnetic absolute encoder 110.

[0054] The encoder signal of the motor-side magnetic absolute encoder 109 and the encoder signal of the reducer-side magnetic absolute encoder 110 support independent or combined communication transmission.

[0055] In an embodiment of the present invention, the encoder signal of the motor-side magnetic absolute encoder 109 and the encoder signal of the speed reducer-side magnetic absolute encoder 110 are combined and transmitted via a differential signal line.

[0056] refer to Figure 1 The dual encoder signals of the present invention are combined and transmitted via differential signal lines on first port 103 and second port 104, achieving communication multiplexing. First port 103 and second port 104 are located on the main control circuit board side, third port 105 is located on the reducer side, and fourth port 106 is located on the motor side. First port 103 and third port 105 enable bidirectional communication, while second port 104 and fourth port 106 enable bidirectional communication.

[0057] The main control circuit board 101 integrates a processor, a non-volatile storage module 102 and a communication module. The main control circuit board 101 is used to perform zero point calibration on the motor side magnetic absolute value encoder 109 and the reducer side magnetic absolute value encoder 110.

[0058] In the embodiment of the present invention, the non-volatile storage module 102 is, for example, FRAM, EEPROM, ferroelectric memory, etc.

[0059] The main control circuit board 101 is used to calibrate the motor side magnetic absolute value encoder 109 and the reducer side magnetic absolute value encoder 110 to zero point, including: synchronous acquisition at the mechanical zero point position, and the current moment of the motor side encoder absolute position value P Motor_Zero The absolute position value P of the encoder on the reducer side Reducer_Zero , recorded and stored in the non-volatile storage module 102 as a reference value for subsequent dual encoder system calibration.

[0060] Specifically, before using the "dual encoder ±360°" position detection algorithm, the two encoders must be "zero-point calibrated." This means recording and storing the current motor-side encoder value and reducer-side encoder value in the non-volatile storage module 102 as reference values ​​for subsequent dual-encoder system calibration.

[0061] Then establish the multi-turn counting reference value N 多圈 =0, which serves as the initial condition for subsequent calculations.

[0062] When the collaborative robot is operating normally, the processor of the main control circuit board 101 uses a multi-turn value storage strategy to periodically record the actual position of the joint or the encoder value on the reducer side, thereby realizing dynamic maintenance of the multi-turn value during operation.

[0063] Specifically, the main control circuit board 101 adopts one of the following two multi-turn value storage strategies to periodically record the actual position of the joint or the encoder value on the reducer side. The two multi-turn value storage strategies include:

[0064] (1) Timing storage mode: stores the current reducer side encoder value P in a fixed period Reducer_Current .

[0065] For example, the encoder value on the reducer side is recorded periodically at a time interval not exceeding 500 ms (eg, every 50 ms).

[0066] That is, the current reducer side encoder value P is stored at a fixed period T (T≤500ms) Reducer_Current ;

[0067] Storage trigger condition: t mod T = 0 (timer interrupt trigger).

[0068] (2) Event trigger storage mode: When the encoder position change ΔP on the reducer side Reducer When the set threshold is exceeded, the encoder value on the reducer side is recorded immediately.

[0069] For example, when the joint rotation angle changes beyond a set threshold (such as ±30°), the reducer side encoder value is immediately recorded.

[0070] That is, when the position change of the reducer side encoder satisfies ΔP Reducer When ≥±30°, the current value is stored immediately;

[0071] Calculation logic: ΔP Reducer =|P Reducer_Current -P Reducer_Store ∣.

[0072] Execute power-on initialization and multi-turn value recovery. Specifically, each time the device is powered on, the main control circuit board 101 reads the offset value of the motor side and reducer side encoder relative to the zero point, and combines the historical records saved in the non-volatile storage module 102 to calculate the current actual multi-turn count value N 多圈 , and then calculate the actual position of the collaborative robot joints.

[0073] Read the last valid reducer side encoder value P in the non-volatile memory Reducer_Store .

[0074] Combined with the current reducer side encoder value P Reducer_Current , calculate the current actual multi-turn count value N 多圈 for:

[0075]

[0076] Where i is the reduction ratio, and R is the single-turn resolution of the reducer. The value of R is determined by the number of bits, for example, 17 bits corresponds to R = 131072. Reducer_Current is the encoder value of the current reducer side; PReducer_Store The last valid encoder value on the reducer side; P Reducer_Zero It is the absolute position value of the encoder on the reducer side.

[0077] Fault tolerance mechanism: Combined with the P stored in the non-volatile storage module 102 Reducer_Store , if P Reducer_Store and P Reducer_Current If the deviation exceeds ±0.5 turns, Reducer_Current Use the method of increasing or decreasing ±1 circle to ensure P Reducer_Store and P Reducer_Current The deviation does not exceed ±0.5 circles, and the default is the last stored P Reducer_Current During this short period of time until power is cut off, the collaborative robot's body joints cannot rotate more than ±0.5 turns.

[0078] The main control circuit board 101 calculates the actual position P of the collaborative robot joint 全局 , that is, the dynamic output joint absolute position P 全局 :

[0079] P 全局 =(N 多圈 ×R')+(P Motor_Current -P motor_zero )

[0080] It should be noted that whether to add or subtract the single-turn value R actually depends on the value of the encoder on the reducer side.

[0081] After calibrating the zero point, it is equivalent to setting the encoders of the reducer and motor ends to position 0; assuming the reduction ratio of the reducer is 100, the reducer rotates 3.6° when the motor rotates 1 circle, and the multi-turn value calculated according to the reducer encoder is increased by 1; when the power is restarted, according to the value of the reducer encoder, for example, 73°, it is known that the motor has rotated a little more than 20 circles, and the actual position of the motor is 20*P+the encoder value of the motor at this time.

[0082] However, in reality, the reducer may have hysteresis. That is, for every 1 revolution of the motor, the reducer may rotate 3.5° or 3.7°. Therefore, when calculating, the relative position of the reducer and motor should be considered to obtain a more realistic multi-turn value. In the above example, 73° is 20.3 revolutions. The encoder of a normal motor should read 0.3 revolutions. It is normal for the actual value to fluctuate around 0.3 revolutions.

[0083] If the motor encoder reads 0.2 turns, then it is normal to follow (20+0.2) turns; if the motor encoder reads 0.9 turns, it means that the deceleration has passed the zero point first, and the motor has not passed the zero point yet, so the estimated 20 turns should actually be 19 turns, and the actual position of the motor should be 19.9 turns.

[0084] Whether to add or subtract the lap value depends on Get the decimal part of the multi-circle value, and combine (P Motor_Current -P Motor_Zero) , the actual position of the motor side encoder can be obtained, and it can be known whether the actual position of the motor side encoder and the position of the motor side encoder estimated by using the reducer side encoder are on the same side or different side of the zero point position.

[0085] If on the same side, then P 全局 There is no need to add or subtract the single-turn motor encoder value R;

[0086] If on the opposite side, and If the decimal part of the multi-turn value is greater than 0.5, then P 全局 The motor encoder value R of a single turn needs to be added;

[0087] If on the opposite side, and If the decimal part of the multi-turn value is less than 0.5, then P 全局 The motor encoder value R of a single turn needs to be subtracted;

[0088] R' is the single-turn resolution of the motor side encoder (the value of R' is determined by the number of bits, such as 17 bits corresponds to R = 131072), N 多圈 is the multi-turn count value, P motor_current is the current motor side encoder reading, P Motor_Zero The absolute position value of the motor encoder. The calculation period is ≤1ms, meeting real-time control requirements.

[0089] The motor drives the output connecting rod to rotate through the reducer. Assuming the reduction ratio is "i", when the motor side encoder rotates "i" circles, the reducer side encoder rotates 1 circle. Figure 2a and Figure 2b As shown in the figure, if the reduction ratio is "i = 120:1", the encoder on the reducer side will only rotate one grid (corresponding to 3°) for every rotation of the motor side encoder.

[0090] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that a specific feature, structure, material, or characteristic described in conjunction with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations 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 any one or more embodiments or examples.

[0091] Those skilled in the art will readily understand that the present invention encompasses any combination of the components described in the Summary and Detailed Description of the Invention and the accompanying drawings. Due to space limitations and for the sake of clarity, not all of the various solutions resulting from these combinations are described. Any modifications, equivalent substitutions, and improvements within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0092] Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are illustrative and are not to be construed as limiting the present invention. Those skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments without departing from the principles and intent of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A system based on dual encoders to achieve 360-degree operation of collaborative robot joints, characterized in that: include: Dual encoder architecture, main control circuit board, first encoder circuit board, second encoder circuit board, reducer and motor, wherein, The dual-encoder architecture includes: a motor-side magnetic absolute encoder and a reducer-side magnetic absolute encoder, wherein the motor-side magnetic absolute encoder is installed on the output shaft of the motor, and the reducer-side magnetic absolute encoder is directly connected to the output shaft of the reducer; The first encoder circuit board is connected to the motor side magnetic absolute value encoder and is used to process the encoder signal of the motor side magnetic absolute value encoder; The second encoder circuit board is connected to the reducer side magnetic absolute encoder and is used to process the encoder signal of the reducer side magnetic absolute encoder; The main control circuit board integrates a processor, a non-volatile storage module and a communication module. The main control circuit board is used to calibrate the zero point of the motor side magnetic absolute encoder and the reducer side magnetic absolute encoder. When the collaborative robot is operating normally, the processor of the main control circuit board adopts a multi-turn value storage strategy to periodically record the actual position of the joint or the reducer side encoder value; each time the equipment is powered on, the main control circuit board reads the offset value of the motor side and reducer side encoder relative to the zero point, and combines the historical records saved in the non-volatile storage module to calculate the current actual multi-turn count value, and then calculates the actual position of the collaborative robot joint.

2. The system for realizing positive and negative 360-degree operation of collaborative robot joints based on dual encoders according to claim 1 is characterized in that: The resolution of the motor-side magnetic absolute encoder is greater than or equal to 17 bits.

3. The system for realizing positive and negative 360-degree operation of collaborative robot joints based on dual encoders according to claim 1 is characterized in that: The encoder signal of the motor-side magnetic absolute encoder and the encoder signal of the reducer-side magnetic absolute encoder support independent or combined communication transmission.

4. The system for realizing positive and negative 360-degree operation of collaborative robot joints based on dual encoders according to claim 3 is characterized in that: The encoder signal of the motor-side magnetic absolute encoder and the encoder signal of the reducer-side magnetic absolute encoder are combined and transmitted via a differential signal line.

5. The system for realizing positive and negative 360-degree operation of collaborative robot joints based on dual encoders according to claim 1 is characterized in that: The motor side magnetic absolute value encoder and the reducer side magnetic absolute value encoder are installed on different sides or on the same side.

6. The system for realizing positive and negative 360-degree movement of collaborative robot joints based on dual encoders according to claim 5 is characterized in that: When the opposite-side installation method is adopted, the motor-side magnetic absolute value encoder and the reducer-side magnetic absolute value encoder are respectively installed on independent circuit boards; When the same-side installation method is adopted, the motor-side magnetic absolute value encoder and the reducer-side magnetic absolute value encoder are installed on a shared circuit board.

7. The system for realizing positive and negative 360-degree operation of collaborative robot joints based on dual encoders according to claim 1 is characterized in that: The main control circuit board is used to calibrate the zero point of the motor side magnetic absolute value encoder and the reducer side magnetic absolute value encoder, including: synchronous acquisition at the mechanical zero point position, and the absolute position value P of the motor side encoder at the current moment. Motor_Zero The absolute position value P of the encoder on the reducer side Reducer_Zero , recorded and stored in the non-volatile storage module as a reference value for subsequent dual encoder system calibration.

8. The system for realizing positive and negative 360-degree operation of collaborative robot joints based on dual encoders according to claim 1 is characterized in that: The main control circuit board uses one of the following two multi-turn value storage strategies to periodically record the actual position of the joint or the encoder value on the reducer side. The two multi-turn value storage strategies include: (1) Timing storage mode: stores the current reducer side encoder value P in a fixed period Reducer_Current ; (2) Event trigger storage mode: When the encoder position change ΔP on the reducer side Reducer When the set threshold is exceeded, the encoder value on the reducer side is recorded immediately.

9. The system for realizing positive and negative 360-degree operation of collaborative robot joints based on dual encoders according to claim 1 is characterized in that: The calculation of the current actual multi-turn count value N 多圈 ,include: Where i is the reduction ratio, R is the single-turn resolution of the reducer side; P Reducer_Current is the current encoder value on the reducer side; P Reducer_Store The last valid encoder value on the reducer side; P Reducer_Zero It is the absolute position value of the encoder on the reducer side.

10. The system for realizing positive and negative 360-degree movement of collaborative robot joints based on dual encoders according to claim 1, characterized in that: The main control circuit board calculates the actual position P of the collaborative robot joint 全局 : P 全局 =(N 多圈 ×R')+(P Motor_Current -P motor_zero ) Among them, R' is the single-turn resolution of the motor side encoder, N 多圈 is the multi-turn count value, P motor_current is the current motor side encoder reading, P Motor_Zero It is the absolute position value of the motor side encoder.

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