Automated control system for hot forming line of automobile sheet metal parts

Abstract

This invention provides an automated control system for an automotive sheet metal thermoforming production line using a remote encoder module, relating to the field of industrial automation control technology. It includes a servo drive cabinet, distributed automated equipment, and a remote encoder position feedback system for realizing servo motor position feedback. The servo drive cabinet is centrally installed in a control room far from the production line, while the automated equipment is distributed across various workstations on the thermoforming production line. The distance between the servo drive cabinet and the servo motors in the automated equipment is no less than 30 meters. This invention uses a local encoder module to collect signals locally, processes the data in the digital domain, and transmits it through a robust industrial network, completely solving the signal degradation problem. The bit error rate remains below 100 meters, while avoiding faults such as bending fatigue and wire breakage in traditional solutions, thus improving system reliability and increasing equipment availability to over 99%.

Description

Technical Field

[0001] This invention relates to the field of industrial automation control technology, and in particular to an automated control system for automotive sheet metal thermoforming production lines using a remote encoder module. Background Technology

[0002] The automotive sheet metal hot forming production line is a key process in automobile manufacturing, mainly used to produce high-strength body structural parts such as A-pillars, B-pillars, and door anti-collision beams. A complete automated hot forming production line typically includes the following sections: the initial section (destacking and loading robots, laser marking systems, etc.), the stamping section (stamping and loading robots, hot forming presses, etc.), and the final section (chain conveyors, vision inspection systems, framing robots, etc.). The fully automated equipment widely uses servo motor drives and requires high-precision absolute encoders for position feedback to meet production accuracy requirements. Due to production site layout limitations, servo drive cabinets are usually centrally installed in the control room far from the production line, often exceeding 30 meters from the on-site servo motors, and sometimes reaching 50-80 meters. Currently, the industry mainly uses three solutions for position signal transmission and control: traditional encoder long cable connections, on-site encoder signal amplifier installation, and distributed servo drives.

[0003] Traditional encoder long-cable connection solutions suffer from severe signal attenuation, poor anti-interference capability, weak protocol compatibility, high cable cost, low reliability, and difficult maintenance, failing to meet the requirements for long-distance, high-precision transmission. On-site encoder signal amplifier solutions require independent power supplies, involve complex wiring, and are highly susceptible to harsh environments, and cannot completely resolve timing and interference issues. Distributed servo drive solutions face challenges such as high temperatures, dust, and vibration affecting equipment operation, difficult heat dissipation, inconvenient maintenance, and extremely high costs. Furthermore, existing solutions cannot adequately balance multi-axis synchronization accuracy, multi-protocol compatibility, cost control, and adaptability to harsh environments, making it difficult to meet the high-precision, high-reliability, and high-scalability control requirements of thermoforming production lines. Therefore, this invention proposes an automated control system for automotive sheet metal thermoforming production lines using a remote encoder module to address the problems existing in the prior art. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes an automated control system for automotive sheet metal thermoforming production lines using a remote encoder module. This system employs a local encoder module to acquire signals from nearby locations, processes the data in the digital domain, and transmits it through a robust industrial network, completely resolving the signal degradation problem. Even at a distance of 100 meters, the bit error rate remains below [percentage missing]. , while avoiding the faults such as bending fatigue and wire breakage of long cables in the traditional solution, improving the system reliability, raising the equipment availability rate to over 99%, and the mean time between failures > 10,000 hours. Compared with the prior art, the stability of long-distance transmission is improved by more than 80%, and the failure rate is reduced by 90%.

[0005] To achieve the object of the present invention, the present invention is realized by the following technical solutions: An automated control system for an automotive sheet metal hot forming production line with a remote encoder module, including a servo drive electrical cabinet, distributed automated equipment, and a remote encoder position feedback system for implementing servo motor position feedback. It is characterized in that: the servo drive electrical cabinet is centrally installed in a control room far from the production line, the automated equipment is distributed at each station of the hot forming production line, and the distance between the servo drive electrical cabinet and the servo motors in the automated equipment is not less than 30 meters;

[0006] The remote encoder position feedback system includes a local encoder module, a remote communication network, and a driver-side interface module. The local encoder module is installed near each servo motor end for collecting the position signals of the absolute encoders supporting the servo motors and performing digital processing. The remote communication network is used to transmit the digital position data processed by the local encoder module to the servo drive electrical cabinet. The driver-side interface module is installed in the servo drive electrical cabinet for receiving the digital position data and restoring it to a signal format recognizable by the servo driver to achieve high-precision position closed-loop control of the servo motor; a centralized power supply module is further provided in the servo drive electrical cabinet for providing stable low-voltage power supply for all local encoder modules; a synchronous capture probe is provided in the local encoder module for receiving an external trigger signal and synchronously locking and storing multi-channel encoder position data.

[0007] A further improvement lies in that: the local encoder module is built with a multi-protocol parsing engine, supporting five or more mainstream absolute encoder communication protocols such as BiSS C, EnDat2.2, Hiperface DSL, SSI, and Tamagawa, and adopting a multi-protocol adaptive recognition algorithm, the algorithm expression is:

[0008] ;

[0009] In the formula, P is the protocol recognition result, P = 1 corresponds to the BiSS C protocol, P = 2 corresponds to the EnDat 2.2 protocol, P = 3 corresponds to the Hiperface DSL protocol, P = 4 corresponds to the SSI protocol, and P = 5 corresponds to the Tamagawa protocol; T is the encoder signal sampling period (unit: ), and the value range is 10 - 100 S represents the characteristic amplitude of the sampled signal (unit: mV), ranging from 50 to 500 mV; f represents the frequency of the sampled signal (unit: MHz), ranging from 1 to 10 MHz; k1, k2, and k3 are the protocol identification weighting coefficients, k1=0.4, k2=0.3, and k3=0.3, respectively, used to adjust the influence of different signal characteristics on the protocol identification results to ensure that the identification accuracy is not less than 99.9%. This indicates the floor function. This indicates the modulo operation.

[0010] A further improvement is that the remote communication network adopts the gLink-II dedicated real-time communication protocol, the EtherCAT protocol, or the PROFINET protocol. When using the gLink-II protocol, the communication cycle is 250. -1ms adjustable, end-to-end transmission delay <50ms Delay jitter <1 Furthermore, a distributed clock synchronization algorithm is used to achieve multi-axis time synchronization. The algorithm expression for synchronization accuracy is as follows:

[0011] ;

[0012] In the formula, Multi-axis synchronization error (unit: ns). ; t1 is the hardware timestamp of the first encoder data (unit: ns); t2 is the hardware timestamp of the second encoder data (unit: ns); The transmission delay difference (in ns) between the two encoder data streams is determined by the topology and transmission medium of the remote communication network and is compensated in real time through a distributed clock synchronization algorithm.

[0013] Further improvements include: the automated equipment comprises at least one of the following: a Cartesian coordinate XYZ manipulator, an articulated robot, a gantry manipulator, a marking and positioning mechanism, a quality inspection and positioning mechanism, a framing manipulator, and an automatic end effector changing device; wherein, the local encoder modules of the X / Y / Z servo axes of a group of Cartesian coordinate manipulators are connected to the same remote communication network via a daisy-chain connection, sharing the same communication module and clock reference, with a time synchronization accuracy <1. The automatic end effector replacement device is equipped with 2-3 servo axes, and its local encoder module is also connected to the remote communication network via a daisy chain, sharing the same time reference with the encoder module of the robot arm.

[0014] A further improvement is that the local encoder module uses hardware timestamp technology, and the time synchronization accuracy between modules is <1. The algorithm expression for ensuring the precision of hardware timestamps is as follows:

[0015] ;

[0016] In the formula, tsync is the synchronization timestamp of the local encoder module (unit: ns); tbase is the reference timestamp of the master station module at the driver end (unit: ns); k is the time calibration coefficient, with a value range of 0.9999-1.0001, used to compensate for the error of the local crystal oscillator; The time difference (unit: ns) is obtained by the system through periodic automatic calibration to ensure timestamp accuracy.

[0017] Further improvements include: the transmission medium of the remote communication network uses Cat5e / Cat6 twisted-pair cable or industrial-grade optical fiber, where the transmission distance of twisted-pair cable is <100 meters and the transmission distance of optical fiber is >100 meters; the remote communication network has a built-in CRC check and error retransmission mechanism to ensure data transmission accuracy, with an error rate < The local encoder module uses an M12 high-protection connector with an IP67 or higher protection rating and a high-temperature resistance range of [missing information]. It is adapted to the high temperature, dust, and vibration environment of thermoforming production lines.

[0018] Further improvements include: the system also includes real-time diagnostic functions, used to monitor the communication quality, signal strength and bit error rate of the remote communication network in real time, while monitoring the working status of the local encoder module, servo motor and absolute encoder, and accurately locating the faulty module and identifying the specific fault point, including the workstation, shaft number and fault type; the system provides remote firmware upgrade and online parameter configuration functions, and controls the mean time to repair (MTTR) to be ≤30 minutes.

[0019] Further improvements include: the centralized power supply module adopts an isolation filter design, with an output voltage of 24V low-voltage DC and a power supply ripple of ≤50mV, used to remove electromagnetic noise in the driver power supply and provide a clean and stable power supply for the local encoder module; the output current of the centralized power supply module is flexibly adjustable according to the number of local encoder modules, supports hot-swapping, and is used for system expansion.

[0020] A further improvement is made in that the local encoder module includes a signal filtering unit to purify the position signal acquired by the absolute encoder and remove electromagnetic interference generated by equipment such as the medium-frequency heating furnace and high-power press in the thermoforming production line. The signal filtering unit adopts a second-order low-pass filtering algorithm, the expression of which is as follows:

[0021] ;

[0022] In the formula, The filtered output position signal after the nth sampling is expressed in pulses, corresponding to the absolute position quantization value fed back by the encoder. The filtered output position signal after the (n-1)th sampling is expressed in pulses, and the result of the filtering at the previous moment is used to ensure the continuity of the filtered output. The filtered output position signal after the (n-2)th sampling is expressed in pulses, and the result of the filtering at the previous moment is used to optimize the smoothness of the filter. , This is the filter feedback coefficient, dimensionless, dynamically adjusted based on the interference intensity of the thermoforming production line. The range of values ​​is , The range of values ​​is It is used to adjust the balance between filter response speed and smoothness; The original position signal of the nth sample is expressed in pulses and is directly acquired by an absolute encoder, containing electromagnetic interference noise. The original position signal of the (n-1)th sample is expressed in pulses, and the original acquisition data is from the previous moment. The original position signal of the (n-2)th sample is expressed in pulses, and the original acquisition data is from the previous moment. , , These are the filter input coefficients, dimensionless, and matched to the sampling frequency of the production line encoder. The range of values ​​is , The range of values ​​is , The range of values ​​is The second-order low-pass filtering algorithm is used to weight the influence of the original sampled signal; it ensures that the amplitude fluctuation of the filtered signal is ≤5mV, thereby improving the accuracy of the location data.

[0023] Further improvements include: the absolute encoder configured on the servo motor has a resolution of 17-23 bits, supporting single-turn or multi-turn absolute position feedback; the total number of servo axes in the automated equipment is 20-60 axes, enabling unified and coordinated control of servo axes throughout the entire production line, meeting the full-process automated control requirements for destacking and loading, stamping and loading, marking, conveying, quality inspection, and framing, and supporting production line upgrades and modifications, flexibly adding new workstations, new equipment, and encoders with different protocols.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. This invention uses a local encoder module to acquire signals nearby, completes data processing in the digital domain, and transmits the data through a robust industrial network, completely solving the signal degradation problem. The bit error rate remains below 100 meters. This technology avoids the problems of bending fatigue and wire breakage in long cables in traditional solutions, improves system reliability, increases equipment availability to over 99%, and has a mean time between failures (MTBF) of over 10,000 hours. Compared with existing technologies, it improves the stability of long-distance transmission by over 80% and reduces the failure rate by 90%.

[0026] 2. This invention utilizes multi-protocol adaptive recognition technology, allowing a single hardware set to be compatible with multiple mainstream encoder protocols. This eliminates the need for dedicated cables and interfaces for different protocols, enabling the use of different brands of servo systems on the same production line and avoiding reliance on a single supplier. Simultaneously, it standardizes spare parts types, reducing spare parts inventory costs by more than 75%. When upgrading or modifying equipment, there is no need to replace the entire encoder feedback system; only software parameters need to be adjusted, significantly reducing procurement and maintenance costs.

[0027] 3. This invention employs hardware timestamps and a distributed clock synchronization algorithm, achieving multi-axis synchronization accuracy <100ns within the same group of robotic arms and cross-group synchronization accuracy <1ns. Synchronization accuracy of all axes on the entire line <10 Compared with traditional solutions, the synchronization accuracy is improved by more than 80%; the XYZ linkage trajectory accuracy of the Cartesian coordinate robot is improved, and complex movements such as circular interpolation are smoother. The position accuracy of the loading and unloading robot can reach ±0.05mm, and the positioning accuracy of the marking system can reach ±0.03mm, meeting the high-precision control requirements of the thermoforming production line.

[0028] 4. This invention adds a probe signal interface to the local encoder module, which can simultaneously latch multiple encoder position data, avoiding the cumbersome process of converting and aggregating encoder data from multiple drivers into one module, reducing system cost and complexity, improving the real-time performance of synchronous capture by more than 60%, and improving accuracy by more than 95%, effectively avoiding positioning deviations and equipment collision risks caused by capture delays.

[0029] 5. This invention provides a clean and stable low-voltage power supply to the remote encoder through a centralized power supply module, which simplifies the isolation and filtering design of the driver and reduces the inherent cost of the driver by more than 30%. At the same time, it isolates the encoder signal from the strong electromagnetic environment of the driver, avoiding the electromagnetic interference generated by power devices such as IGBTs from affecting the signal quality. It can still work stably in a strong interference environment and the communication error rate is reduced to zero. Attached Figure Description

[0030] Figure 1 This is a diagram illustrating the composition of the present invention. Detailed Implementation

[0031] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0032] Example 1

[0033] according to Figure 1 As shown in the figure, this embodiment proposes an automated control system for automotive sheet metal hot forming production lines using a remote encoder module. The system includes a servo drive cabinet, automated equipment, a remote encoder position feedback system, power cables, and a communication network. The specific structure is as follows:

[0034] Servo drive cabinet: centrally installed in the control room far away from the production line, containing 20-40 servo drives, PLC controller, motion controller, human-machine interface, remote encoder master station module and centralized power supply module. The centralized power supply module is used to provide stable low-voltage power supply for all remote encoder modules, simplifying drive design and reducing power supply costs.

[0035] Automated equipment: Distributed and installed at various workstations of the thermoforming production line, including destacking and loading robots, stamping loading robots, stamping unloading robots, marking and positioning mechanisms, quality inspection and positioning mechanisms, framing robots, and automatic end effector changing devices. The robots can take various forms such as rectangular coordinate XYZ structure, articulated robots, and gantry robots. Each servo motor is equipped with an absolute encoder with a resolution of 17-23 bits and supports multiple communication protocols.

[0036] The remote encoder position feedback system consists of a local encoder module, a remote communication network, and a driver-side interface module (master station module). The local encoder module is installed at the end of each servo motor and connects to an absolute encoder (connection cable length < 1 meter) via an M12 high-protection interface. It incorporates a multi-protocol parsing engine, a hardware timestamp unit, a synchronization capture probe, and a signal filtering unit, enabling protocol parsing, position data extraction, timestamp marking, synchronization latching, and signal purification. The remote communication network uses industrial Ethernet or Googol's proprietary gLink-II real-time communication protocol, supporting various topologies such as daisy chain and star, enabling long-distance, high-speed transmission of digital position data. The driver-side interface module is installed in the servo drive cabinet, receiving remotely transmitted position data and restoring it to the signal format required by the servo drive, or directly communicating with the motion controller via a digital interface.

[0037] Power cable: Connects the servo driver and the servo motor, used to transmit three-phase power, without the need for additional encoder signal carrying, reducing cable loss and interference;

[0038] Communication network: Cat5e / Cat6 twisted pair or optical fiber is used as the transmission medium to realize high-speed, reliable, deterministic real-time communication between remote encoder modules and between remote encoder modules and driver-end master station modules. The optical fiber transmission scheme can be adapted to strong interference and ultra-long distance (>100 meters) scenarios.

[0039] Working principle

[0040] Signal Acquisition and Preprocessing: The local encoder module acquires the position signal of the absolute encoder nearby via a short cable, automatically adapts and parses it according to the encoder protocol type, and at the same time, the signal is purified by the signal filtering unit to remove noise caused by electromagnetic interference; the synchronous capture probe receives external trigger signals and synchronously latches the position data of multiple encoders, avoiding the cumbersome process of additional conversion output of multiple drivers;

[0041] Local processing and packaging: The local encoder module performs protocol parsing, location data extraction, and nanosecond-level hardware timestamp marking on the collected raw data. It packages the location data, timestamp, status information, and checksum into a data frame with a unified format. At the same time, it obtains a stable low-voltage power supply through the centralized power supply module to ensure the stability of data processing.

[0042] High-speed transmission and delay compensation: Data frames are transmitted to the driver in a deterministic manner via the gLink-II dedicated real-time communication protocol or industrial Ethernet. A distributed clock synchronization algorithm is used to compensate for network transmission delay and ensure that the time base of multi-axis data is consistent.

[0043] Signal restoration and closed-loop control: After receiving the position data, the master station module on the driver side restores it to the corresponding encoder protocol format according to the requirements of the servo driver interface, or directly transmits the digital position data to the motion controller. The servo driver or motion controller performs high-precision closed-loop control based on the position feedback signal, driving the motor to move precisely to the target position.

[0044] Fault diagnosis and maintenance: The system monitors parameters such as communication quality, signal strength, and bit error rate in real time, which can accurately locate the fault point, support remote firmware upgrades and parameter configuration, and shorten the fault repair time.

[0045] Long-distance digital transmission optimized design: Adopting a "local acquisition + digital transmission" architecture, the local encoder module connects to the encoder nearby, avoiding attenuation and interference caused by long cable transmission of analog signals. Combined with a fiber optic transmission scheme, it achieves high-precision signal transmission over distances exceeding 100 meters, with a bit error rate of < 0.05%. ;

[0046] Multi-protocol adaptive recognition technology: Built-in multi-protocol parsing engine, supporting more than 5 mainstream absolute encoder protocols such as BiSS C, EnDat 2.2, Hiperface DSL, SSI, and Tamagawa. Protocols can be switched through software parameter configuration or automatic recognition without replacing hardware.

[0047] Nanosecond-level multi-axis synchronous control technology: Employing hardware timestamp technology and distributed clock synchronization algorithm, multiple axes of the same group of manipulators share a single communication module and clock reference, achieving nanosecond-level synchronization and improving the accuracy of multi-axis collaborative control;

[0048] Synchronous capture optimization technology: A probe signal interface is added to the local encoder module, which can synchronously latch multiple encoder position data, reduce system complexity, and improve the real-time performance and accuracy of capture;

[0049] Centralized power supply and electromagnetic isolation design: A centralized power supply module provides a clean and stable low-voltage power supply to all remote encoder modules, simplifying driver design and reducing costs; the encoder signal is isolated from the strong electromagnetic environment of the driver, avoiding electromagnetic interference from affecting signal quality.

[0050] Example 2

[0051] according to Figure 1 As shown, this embodiment proposes an automated control system for automotive sheet metal hot forming production lines using a remote encoder module, including a stamping loading and unloading robot system based on the gLink-II protocol:

[0052] System configuration: The automotive B-pillar hot stamping production line adopts 4 sets of rectangular coordinate XYZ structure robots (2 sets for loading and 2 sets for unloading). Each loading robot is equipped with an X-axis (1.5kW) + Y-axis (1kW) + Z-axis (0.75kW), and each unloading robot is equipped with an X-axis (1kW) + Y-axis (0.75kW) + Z-axis (0.5kW). Each stamping loading and unloading station is equipped with one set of end effector replacement device, each set including an X-axis (0.4kW) + Y-axis (0.4kW), for a total of 4 axes. Each motor is equipped with a 23-bit BiSS C absolute encoder (single revolution). The distance between the servo drive cabinet and the robot is 45 meters (loading), 50 meters (unloading), and 48 meters (end effector replacement device).

[0053] Hardware Connection: Each servo motor is equipped with an M12 high-protection gLink-II remote encoder module (transmitter) at its tail. The module is connected to the BiSS C encoder via a 0.5-meter M12 interface short cable. The three encoder modules (X / Y / Z axes) of each set of Cartesian coordinate robots are connected in series via a daisy chain using a 0.3-meter M12 interface connecting cable. The four sets of robots are connected to the drive cabinet via four CAT5e twisted pair cables. The drive cabinet is equipped with a gLink-II master station module (receiver) connected to the motion controller. It is also equipped with a centralized power supply module to provide 24V low-voltage power to all remote encoder modules.

[0054] Communication parameters: The communication protocol adopts the gLink-II dedicated real-time protocol, with a communication cycle of 250. Data update rate per axis: 4000 times / second; end-to-end latency: <50 seconds. The synchronization accuracy of the XYZ three axes within the same group of robotic arms is <100ns, and the BiSS C protocol rate is 10Mbps.

[0055] Key features: The X, Y, and Z axes of each Cartesian coordinate robot are managed by a single communication module, sharing a clock reference for extremely high time synchronization accuracy; it supports collaborative operation in a dual-robot shuttle mode, with a synchronization error of <10 between the two sets of loading robots. The gLink-II module has a built-in encoder protocol conversion function, which can be adapted to different brands of BiSS encoders through parameter configuration; the centralized power supply module provides stable power supply for all remote encoders, avoiding the influence of driver power supply noise.

[0056] Implementation results: Position control accuracy ±0.05mm (better than the design requirement of ±0.1mm); Synchronization error of the XYZ axes of a single robot arm <5. (Traditional solutions are approximately 50-100) The synchronization error of the two robotic arms is <10. (Traditional solutions cost approximately 100-200) The system ran continuously for 8 months with zero failures; cable costs were reduced by approximately 12,000 yuan (compared to traditional BiSS dedicated shielded cable solutions); installation and commissioning time was shortened by 40%; driver costs were reduced by 30% and power supply stability was improved by 85%.

[0057] Example 3

[0058] according to Figure 1 As shown, this embodiment proposes an automated control system for automotive sheet metal thermoforming production lines using a remote encoder module, including a fully automated production line system based on the gLink-II protocol:

[0059] System Configuration: The automotive door outer panel hot stamping forming production line includes automated equipment such as two 6-axis articulated depalletizing and loading robots (12 axes total), one set of automatic end effector changing device for the depalletizing station (XYZ three axes), two sets of automatic end effector changing devices for the stamping station (each set with two XY axes, totaling four axes), one 2×6 structure marking system (6 marking heads, each with two XY axes, totaling 12 axes), two sets of stamping loading robots (each with three XYZ axes, totaling six axes), two sets of stamping unloading robots (each with three XYZ axes, totaling six axes), one quality inspection positioning axis, and two 6-axis articulated framing robots (12 axes total), totaling 56 servo axes. The servo drive cabinet is 70 meters away from the furthest equipment (the depalletizing and loading robot at the beginning of the line). Encoder Configuration: The depalletizing and loading / framing robots use EnDat 2.2 absolute encoders (NIDEC brand, Japan), and the loading and unloading robots use BiSS encoders. The C absolute encoder (German Sick brand), and the marking system and end effector replacement device use the Hiperface DSL absolute encoder (domestic brand).

[0060] Hardware Connection: Each servo motor is equipped with a gLink-II remote encoder module supporting multiple protocols. The module automatically identifies the encoder type through parameter configuration. Equipment Group Connection: Each depalletizing and loading robot is divided into 2 groups (3 front axes + 3 rear axes), with each group using 1 gLink-II communication module, for a total of 4 modules; the depalletizing station end effector replacement device uses 1 module, and the stamping station end effector replacement device uses 2 modules; the marking system has 6 groups of marking heads, each group using 1 module, for a total of 6 modules; the stamping loading and unloading robots have 4 groups, for a total of 4 modules; the framing robots have 2 units, for a total of 4 modules; the quality inspection positioning axis uses 1 module, for a total of 23 gLink-II communication modules throughout the line; a CAT6 twisted-pair backbone network is used, and the depalletizing and loading section at the beginning of the line (70 meters) uses industrial-grade fiber optic connection; the drive cabinet is equipped with a gLink-II master station module and a centralized power supply module to uniformly manage the position data and power supply of all 56 servo axes.

[0061] Key technologies: Employing gLink-II hardware timestamp technology, all 56 axes share a unified time base with synchronization accuracy <100ns; a hybrid network of fiber optic + twisted pair cables adapts to different distances and interference environments; the remote encoder module has built-in multi-protocol support, and the same system is compatible with BiSS, EnDat, and Hiperface encoders; optimized integrated depalletizing and loading process, with the robot completing the entire process of gripping, marking, detection, loading / waste removal, all coordinated by gLink-II; the automatic end effector changing system shares the same gLink-II network with the robot axes, achieving precise coordination between gripper changing actions and robot movement; the marking system achieves nanosecond-level synchronization of each group's X / Y axes, ensuring marking accuracy; the 6-axis robot is managed in two groups, front 3 axes and rear 3 axes, improving the accuracy of joint linkage trajectories.

[0062] Implementation Results: The trajectory accuracy of the entire 56-axis linkage is ±0.08mm; it operates stably at a distance of 2 meters from a 150kW medium-frequency heating furnace and a press weighing several thousand tons, with a communication error rate of <10%. -12 The integrated depalletizing and loading system achieves a single-cycle time of less than 18 seconds, reducing the scrap rate from 3.5% to 0.2%; the automatic end effector replacement cycle is shortened from 8 minutes to 8 seconds, increasing production changeover efficiency by 60 times; marking position accuracy is ±0.03mm, and marking clarity pass rate is >99.9%; the 6-axis robot end effector jitter is reduced from ±0.5mm to ±0.1mm, and the grasping success rate is increased from 98.5% to 99.8%; the measured communication latency is 42 seconds. The synchronization accuracy of all 56 axes is <8. System debugging time was reduced by 50%; cable costs were reduced by approximately 85,000 yuan; multi-protocol compatibility reduced procurement costs by 15%; system availability was 99.94%, and only one encoder module alarm occurred (loose plug) during 10 months of continuous operation, which was quickly resolved through remote diagnostics.

[0063] Example 4

[0064] according to Figure 1 As shown, this embodiment proposes an automated control system for automotive sheet metal thermoforming production lines using a remote encoder module, including a hybrid robotic arm structure and the application of a flexible encoder protocol:

[0065] Application scenario: A joint venture car factory is building a new A-pillar hot forming line, which adopts a hybrid robotic arm structure and is required to support future production line upgrades and be compatible with servo motors and encoders from various brands.

[0066] System configuration: 1 set of cantilevered rectangular coordinate XYZ structure destacking and loading robot (3 axes) + 1 rotary axis (4 axes in total), 2 sets of gantry-type rectangular coordinate XYZ structure stamping loading robot (3 axes each, 6 axes in total), 1 set of truss-type rectangular coordinate XYZ structure stamping unloading robot (3 axes) + 1 set of 6-axis articulated robot (9 axes in total), for a total of 19 servo axes; Encoder configuration: the cantilever robot uses EnDat 2.2 encoder (integrated with Beckhoff servo motors), the gantry robot uses BiSS C encoder (integrated with German SEW servo motors), the truss robot uses Hiperface DSL encoder (integrated with Siemens servo motors), and the articulated robot uses SSI encoder (domestic encoder).

[0067] Hardware connectivity: All 19 servo axes are equipped with universal gLink-II remote encoder modules, supporting four protocols: BiSS / EnDat / Hiperface / SSI; the X / Y / Z axes of each Cartesian robot are connected through a gLink-II communication module, and the 6 axes of the articulated robot are divided into two groups (3 front axes and 3 rear axes), with each group using a gLink-II communication module; the entire line uses a gLink-II network, using a mix of twisted-pair cables (within 50 meters) and fiber optics (above 50 meters); through software parameter configuration, each module automatically identifies and adapts to the corresponding encoder protocol; a centralized power supply module is configured to provide stable low-voltage power to all remote encoder modules.

[0068] Advantages of flexibility: The protocol is adaptive, and when changing to a different brand of servo motor, only the software parameters need to be modified, without changing the encoder module hardware; it is convenient for future upgrades, and there are plans to add an AGV conveyor system (with another brand of servo motor) at the end of the line, which can be directly connected to the existing network; spare parts management is simplified, and the same model of encoder module is used throughout the line, reducing the variety of spare parts and inventory costs; the supplier is highly flexible and not bound to a single servo motor brand, and can be flexibly selected according to cost and delivery time.

[0069] Implementation Results: Successfully implemented mixed use of four encoder protocols with stable system operation; subsequent upgrades to add a 2-axis AGV positioning system (using Tamagawa encoders) were completed in just one day; spare parts inventory was reduced by 75% (from requiring four types of encoder interface modules to only one); procurement flexibility was improved, with the servo motor for the depalletizing robot switching from Beckhoff to a domestic brand, saving 15% in costs, and the switchover process requiring only 2 hours of parameter adjustment; centralized power supply reduced driver costs by 30% and improved power supply stability by 80%; synchronization accuracy <100ns, positioning accuracy ±0.06mm.

[0070] Example 5

[0071] according to Figure 1 As shown, this embodiment proposes an automated control system for automotive sheet metal hot forming production lines using a remote encoder module, including a stamping loading and unloading coordination system based on synchronous capture functionality:

[0072] Application scenario: A thermoforming production line of an OEM requires precise coordination between dual stamping loading robots and presses. The position data of the two robots need to be captured simultaneously to avoid collisions and improve production efficiency.

[0073] System configuration: 2 sets of gantry-type rectangular coordinate XYZ structure stamping loading robots (3 axes per set, 6 axes in total), 1 2000-ton hot forming press, 1 set of end effector automatic changing device (2 axes), a total of 8 servo axes; the servo drive cabinet is 55 meters away from the robot; each motor is equipped with a 22-bit BiSS C absolute encoder; the local encoder module is equipped with a synchronous capture probe interface to connect to the press trigger signal.

[0074] Hardware Connection: The three encoder modules of each robot arm are daisy-chained together and share one gLink-II communication module. The end effector replacement device uses one gLink-II communication module, for a total of three communication modules. CAT6 twisted-pair cables are used to connect to the gLink-II master station module in the drive cabinet. A centralized power supply module supplies power to all remote encoder modules. The synchronous capture probe interface receives the press's stamping completion trigger signal and synchronously latches the X / Y / Z axis position data of the two robots.

[0075] Key technologies: A synchronous capture algorithm is adopted, which is triggered by probe signals to synchronously latch the position data of the two robotic arms to ensure the consistency of coordinated actions; combined with the nanosecond-level synchronization accuracy of the gLink-II protocol, the precise handover of the two robotic arms is achieved; the local encoder module has a built-in signal filtering unit to remove signal noise caused by press vibration; and a multi-protocol parsing engine ensures stable parsing of the BiSS C encoder.

[0076] Implementation results: Synchronous capture response time < 10 The synchronization error of the two robotic arms' position data is less than 50ns; the coordination accuracy between the robotic arms and the press is ±0.04mm, avoiding the risk of collisions; the single loading and unloading cycle time is reduced from 5 seconds to 4.2 seconds, increasing production efficiency by 16%; the system has operated continuously for 6 months without any collision failures; the accuracy of synchronous capture reaches 99.99%, compared to traditional solutions (synchronization capture error >100ns). The accuracy is improved by 95%; cable costs are reduced by approximately 8,000 yuan, and maintenance costs are reduced by 60%.

[0077] Example 6

[0078] according to Figure 1 As shown, this embodiment proposes an automated control system for automotive sheet metal thermoforming production lines using a remote encoder module, including a multi-protocol hybrid thermoforming production line system based on centralized power supply:

[0079] Application scenario: A private car company is building a new thermoforming production line with a limited budget. It needs to use servo motors and encoders from different brands, while reducing equipment procurement and operating costs. It also requires improved power supply stability and anti-interference capabilities.

[0080] System configuration: 1 six-axis articulated depalletizing robot (6 axes), 1 set of three-axis Cartesian coordinate XYZ structure loading robot, 1 set of three-axis Cartesian coordinate XYZ structure unloading robot, 1 set of two-dimensional marking system (4 marking heads, 8 axes in total), 1 set of automatic end effector changing device (2 axes), totaling 22 servo axes; the servo drive cabinet is 60 meters away from the furthest equipment; encoder configuration: the depalletizing robot uses Tamagawa encoders (Japanese servo), the loading and unloading robots use SSI encoders (domestic servo), and the marking system uses Hiperface DSL encoders (domestic servo); a centralized power supply module is configured to provide 24V low-voltage power to all 22 remote encoder modules.

[0081] Hardware Connections: The 6-axis depalletizing robot is divided into 2 groups (3 front axes + 3 rear axes), with each group using one gLink-II communication module; each loading and unloading robot uses one gLink-II communication module; each of the 4 marking heads in the marking system uses one gLink-II communication module; the end effector changing device uses one gLink-II communication module, for a total of 8 communication modules; fiber optic transmission (60-meter distance) is used, and the gLink-II master station module is installed in the drive cabinet to connect the PLC and motion controller; the local encoder module automatically identifies and adapts to three different encoder protocols through software parameter configuration.

[0082] Key technologies: The centralized power supply module adopts an isolation filtering design to provide clean and stable low-voltage power supply for the encoder, simplifying the power supply design of the driver; the multi-protocol adaptive identification algorithm automatically matches encoders of different brands and protocols; the fiber optic transmission scheme isolates electromagnetic interference and ensures long-distance transmission stability; the ultra-low latency of the gLink-II protocol improves the system response speed.

[0083] Implementation Results: Successfully implemented the mixed use of Tamagawa, SSI, and Hiperface DSL protocols with stable system operation; centralized power supply reduced driver procurement costs by 30%, power supply noise by 90%, and encoder signal quality by 85%; fiber optic transmission bit error rate < It operates stably near medium-frequency heating furnaces; positioning accuracy is ±0.07mm, and repeatability is ±0.03mm; system debugging time is reduced by 45%, and spare parts costs are reduced by 75%; annual fault repair costs are reduced from 20,000 yuan to 3,000 yuan, and the total life cycle cost is reduced by 58%.

[0084] Validation data:

[0085] The key performance indicators, cost, and reliability data of the embodiments of the present invention are summarized below, and compared with existing traditional solutions, as shown in the table below:

[0086]

[0087] As can be seen from the above data, compared with the existing traditional solutions, the present invention has significantly improved performance indicators such as synchronization accuracy, communication delay, positioning accuracy, and bit error rate. At the same time, it has obvious advantages in cost control, equipment reliability, and debugging efficiency, fully meeting the automation control requirements of automotive sheet metal hot forming production lines, and has good flexibility and scalability.

[0088] The remote encoder module in the automated control system of the automotive sheet metal thermoforming production line uses a local encoder module to acquire signals from nearby locations. After data processing in the digital domain, it is transmitted through a robust industrial network, completely solving the signal degradation problem. The bit error rate remains below 100 meters. This invention avoids the problems of long cable bending fatigue and breakage in traditional solutions, improving system reliability and increasing equipment availability to over 99%, with a mean time between failures (MTBF) of over 10,000 hours. Compared with existing technologies, the stability of long-distance transmission is improved by over 80%, and the failure rate is reduced by 90%. Through multi-protocol adaptive identification technology, a single hardware device is compatible with multiple mainstream encoder protocols, eliminating the need for dedicated cables and interfaces for different protocols. This allows for the use of different brands of servo systems on the same production line, avoiding dependence on a single supplier. Simultaneously, it standardizes spare parts types, reducing spare parts inventory costs by over 75%. During equipment upgrades, there is no need to replace the entire encoder feedback system; only software parameters need to be adjusted, significantly reducing procurement and maintenance costs. This invention employs hardware timestamps and a distributed clock synchronization algorithm, achieving multi-axis synchronization accuracy of <100ns within the same group of robotic arms and <1ns across different groups of robotic arms. Synchronization accuracy of all axes on the entire line <10 Compared to traditional solutions, this invention improves synchronization accuracy by over 80%; the XYZ linkage trajectory accuracy of the Cartesian coordinate robot is improved, and complex movements such as circular interpolation are smoother. The positional accuracy of the loading and unloading robot can reach ±0.05mm, and the positioning accuracy of the marking system can reach ±0.03mm, meeting the high-precision control requirements of thermoforming production lines. This invention adds a probe signal interface to the local encoder module, which can synchronously latch multiple encoder position data, avoiding the cumbersome process of converting and aggregating encoder data from multiple drivers into a single module, reducing system cost and complexity. The real-time performance of synchronous capture is improved by over 60%, and the accuracy by over 95%, effectively avoiding positioning deviations and equipment collision risks caused by capture delays. This invention provides a clean and stable low-voltage power supply to the remote encoder through a centralized power supply module, simplifying the isolation and filtering design of the driver and reducing the inherent cost of the driver by over 30%. Simultaneously, it isolates the encoder signal from the strong electromagnetic environment of the driver, avoiding electromagnetic interference from power devices such as IGBTs from affecting signal quality. It can still work stably in strong interference environments, reducing the communication error rate to zero.

[0089] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An automated control system for an automotive sheet metal hot forming production line using a remote encoder module, comprising a servo drive cabinet, distributed automated equipment, and a remote encoder position feedback system for realizing servo motor position feedback, characterized in that: The servo drive electrical cabinets are centrally installed in a control room far away from the production line. The automation equipment is distributed at each station of the hot forming production line. The distance between the servo drive electrical cabinets and the servo motors in the automation equipment is not less than 30 meters. The remote encoder position feedback system includes a local encoder module, a remote communication network, and a driver-side interface module. The local encoder module is installed near each servo motor end for collecting the position signals of the absolute encoders supporting the servo motors and performing digital processing. The remote communication network is used to transmit the digital position data processed by the local encoder module to the servo drive electrical cabinets. The driver-side interface module is installed in the servo drive electrical cabinets for receiving the digital position data and restoring it to a signal format recognizable by the servo driver, realizing high-precision position closed-loop control of the servo motors. A centralized power supply module is also provided in the servo drive electrical cabinets for providing stable low-voltage power supply for all local encoder modules. The local encoder module is provided with a synchronous capture probe for receiving external trigger signals and synchronously latching multi-channel encoder position data.

2. The automated control system for automotive sheet metal hot forming production line according to claim 1, characterized in that: The local encoder module is built-in with a multi-protocol parsing engine, supporting five or more mainstream absolute encoder communication protocols such as BiSS C, EnDat 2.2, Hiperface DSL, SSI, and Tamagawa, and adopting a multi-protocol adaptive recognition algorithm. The algorithm expression is: ； In the formula, P represents the protocol identification result, P=1 corresponds to the BiSS C protocol, P=2 corresponds to the EnDat 2.2 protocol, P=3 corresponds to the Hiperface DSL protocol, P=4 corresponds to the SSI protocol, and P=5 corresponds to the Tamagawa protocol; T is the encoder signal sampling period (unit: The value range is 10-100. S is the characteristic amplitude of the sampled signal (unit: mV), ranging from 50 to 500 mV; f is the frequency of the sampled signal (unit: MHz), ranging from 1 to 10 MHz. k1, k2, and k3 are protocol identification weight coefficients, with k1=0.4, k2=0.3, and k3=0.3, used to adjust the influence of different signal characteristics on the protocol identification results to ensure that the identification accuracy is not less than 99.9%. This indicates the floor function. This indicates the modulo operation.

3. The automated control system for automotive sheet metal thermoforming production line according to claim 1, characterized in that: The remote communication network adopts the gLink-II dedicated real-time communication protocol, EtherCAT protocol, or PROFINET protocol. When using the gLink-II protocol, the communication cycle is 250. -1ms adjustable, end-to-end transmission delay <50ms Delay jitter <1 Furthermore, a distributed clock synchronization algorithm is used to achieve multi-axis time synchronization. The algorithm expression for synchronization accuracy is as follows: ； In the formula, Multi-axis synchronization error (unit: ns). ; t1 is the hardware timestamp of the first encoder data (unit: ns); t2 is the hardware timestamp of the second encoder data (unit: ns). The transmission delay difference (in ns) between the two encoder data streams is determined by the topology and transmission medium of the remote communication network and is compensated in real time through a distributed clock synchronization algorithm.

4. The automated control system for automotive sheet metal thermoforming production line according to claim 1, characterized in that: The automated equipment includes at least one of the following: a Cartesian coordinate XYZ manipulator, an articulated robot, a gantry manipulator, a marking and positioning mechanism, a quality inspection and positioning mechanism, a framing manipulator, and an end effector automatic changing device; wherein, the local encoder modules of the X / Y / Z servo axes of a group of Cartesian coordinate manipulators are connected to the same remote communication network via a daisy-chain connection, sharing the same communication module and clock reference, with a time synchronization accuracy <1. The automatic end effector replacement device is equipped with 2-3 servo axes, and its local encoder module is also connected to the remote communication network via a daisy chain, sharing the same time reference with the encoder module of the robot arm.

5. The automated control system for automotive sheet metal thermoforming production line according to claim 1, characterized in that: The local encoder module employs hardware timestamp technology, and the time synchronization accuracy between modules is <1. The algorithm expression for ensuring the precision of hardware timestamps is as follows: ； In the formula, tsync is the synchronization timestamp of the local encoder module (unit: ns); tbase is the reference timestamp of the master station module at the driver end (unit: ns); k is the time calibration coefficient, with a value range of 0.9999-1.0001, used to compensate for the error of the local crystal oscillator; The time difference (unit: ns) is obtained by the system through periodic automatic calibration to ensure timestamp accuracy.

6. The automated control system for automotive sheet metal thermoforming production line according to claim 1, characterized in that: The remote communication network uses Cat5e / Cat6 twisted-pair cable or industrial-grade optical fiber as the transmission medium, with twisted-pair cable transmission distance <100 meters and optical fiber transmission distance >100 meters. The remote communication network incorporates CRC checksum and error retransmission mechanisms to ensure data transmission accuracy, with an error rate < The local encoder module uses an M12 high-protection connector with an IP67 or higher protection rating and a high-temperature resistance range of [missing information]. It is adapted to the high temperature, dust, and vibration environment of thermoforming production lines.

7. The automated control system for automotive sheet metal thermoforming production line according to claim 1, characterized in that: The system also includes a real-time diagnosis function for real-time monitoring of the communication quality, signal strength, and bit error rate of the remote communication network, while monitoring the working states of the local encoder module, servo motors, and absolute encoders, and precisely locating the faulty module and identifying specific fault points, including the station, axis number, and fault type. The system provides remote firmware upgrade and parameter online configuration functions, and controls the mean time to repair MTTR ≤ 30 minutes.

8. The automated control system for automotive sheet metal thermoforming production line according to claim 1, characterized in that: The centralized power supply module adopts an isolation and filtering design, with an output voltage of 24V low-voltage direct current and a power supply ripple ≤ 50mV, for removing electromagnetic noise in the driver power supply and providing clean and stable power supply for the local encoder module. The output current of the centralized power supply module is flexibly adjusted according to the number of local encoder modules and supports hot plugging for system expansion.

9. The automated control system for automotive sheet metal thermoforming production line according to claim 1, characterized in that: The local encoder module is provided with a signal filtering unit for purifying the position signals collected by the absolute encoders and removing electromagnetic interference generated by equipment such as intermediate frequency heating furnaces and high-power presses in the hot forming production line. The signal filtering unit adopts a second-order low-pass filtering algorithm. The algorithm expression is: ； In the formula, The filtered output position signal after the nth sampling is expressed in pulses, corresponding to the absolute position quantization value fed back by the encoder. The filtered output position signal after the (n-1)th sampling is expressed in pulses, and the result of the filtering at the previous moment is used to ensure the continuity of the filtered output. The filtered output position signal after the (n-2)th sampling is expressed in pulses, and the result of the filtering at the previous moment is used to optimize the smoothness of the filter. , This is the filter feedback coefficient, dimensionless, dynamically adjusted based on the interference intensity of the thermoforming production line. The range of values ​​is , The range of values ​​is It is used to adjust the balance between filter response speed and smoothness; The original position signal of the nth sample is expressed in pulses and is directly acquired by an absolute encoder, containing electromagnetic interference noise. The original position signal of the (n-1)th sample is expressed in pulses, and the original acquisition data is from the previous moment. The original position signal of the (n-2)th sample is expressed in pulses, and the original acquisition data is from the previous moment. , , These are the filter input coefficients, dimensionless, and matched to the sampling frequency of the production line encoder. The range of values ​​is 0.1~0.3, The range of values ​​is , The range of values ​​is The second-order low-pass filtering algorithm is used to weight the influence of the original sampled signal; it ensures that the amplitude fluctuation of the filtered signal is ≤5mV, thereby improving the accuracy of the location data.

10. The automated control system for automotive sheet metal thermoforming production line according to claim 1, characterized in that: The absolute encoders supporting the servo motors have a resolution of 17 - 23 bits and support single-turn or multi-turn absolute position feedback. The total number of servo axes of the automation equipment is 20 - 60 axes, which can achieve unified coordinated control of all servo axes in the production line, meet the full-process automation control requirements of unstacking and loading, stamping loading and unloading, marking, conveying, quality inspection, and boxing, and support the upgrade and transformation of the production line, flexibly adding new stations, new equipment, and encoders with different protocols.

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