A new drive system and control device for servo press

Abstract

The present invention relates to the field of forging machinery and motor control technology, and in particular to a new type of motor and control device for a servo press, including an external input signal of a servo press, a human-machine interaction interface, a motion control function module, a high-level protocol stack COE and TCPIP protocol stack, an instruction parsing module, a ucosⅡ embedded operating system, a motor control state machine, a motor control module, a hardware current signal conditioning circuit, a position signal conditioning circuit, fault protection and PWM and other functional hardware, a power drive circuit, a six-phase full-bridge IGBT module, two three-phase linear motor phases, two three-phase linear motor position sensors, a sampling circuit and a slider. The technical solution proposed by the present invention is to integrate a motion controller and two servo controllers into one, eliminate communication delays, cancel gears and eliminate gaps, and improve the control accuracy of the slider position; due to the use of two motors for independent control, closed-loop real-time control of the left and right balance of the slider can be achieved.

Description

Technical Field

[0001] The invention relates to the technical field of forging machinery and motor control, and in particular to a new drive system and control device of a servo press. Background Art

[0002] Patent number CN105700453B, "A Control System and Control Method for an Intelligent Servo Press", proposes a control system solution for a servo press using Inovance PLC and Inovance servo driver. The solution is novel, but has a fatal disadvantage - it is not universal. The transmission ratio of the servo transmission mechanism described in the article is a mechanical transmission ratio calculated by the CPU. This cannot realize the function of motion control of presses with different connecting rod types, because the reduction ratio and transmission ratio of the entire motion control process are calculated by the servo control, rather than input according to the mechanical design dimensions. The fundamental reason for this problem is that the control system is equipped with Inovance's universal servo driver, rather than a servo drive control system dedicated to the press.

[0003] The patent number of China Southern Airlines, CN103660361B, "A Servo Press Control System" describes the use of embedded methods to implement the entire control logic and motor control operation of the press, ARM9 to implement the whole machine logic control and motion control unit, FPGA to implement servo motor operation and control, and equipped with an embedded real-time operating system and real-time kernel. ARM9 and FPGA communication bus communication, communication delay will affect the FPGA control motor delay of at least two PWM cycles, and no dual motor synchronization control solution is provided.

[0004] Patent number of Guangdong Industrial Research Institute is CN106881903A "A Servo Press Control System", which states that the whole machine control system includes two cores: motion controller and servo controller. The motion controller is connected to the IO interface module, operation panel and human-machine interface. The motion controller includes PLC and motion control unit. In general, the stability of motion controller is far inferior to PLC, and the communication delay between motion controller and servo controller will affect at least multiple control cycles of motor operation or more, seriously affecting the control performance of servo motor.

[0005] Yangli's patent number is CN1021183911A "Control System of Servo Press" and its content is the mainstream servo press control system in the current industry. It mainly consists of three parts: core control unit PLC, motion control unit and servo drive unit, which respectively serve as the logic input and output of the servo press, motion control curve and feedback calculation, and motor drive and operation. The advantages are clear structure and distinct functions, but the disadvantages are that the signal transmission between the motion controller and the servo drive needs to be transmitted through CAN or SSCNET or other high-speed communication protocols. The data communication delay caused by the communication process during the movement affects the dynamic response of the motor controller. At the same time, the dual motor synchronization function is not clear.

[0006] The patent number CN101396876B applied for by Shanghai Jiao Tong University is named "Dual-motor mechanically coordinated synchronous slider driven eight-rod servo press". It adopts a dual-motor mechanically coordinated synchronous slider drive connection device, which can realize large-tonnage stretching and servo functions. However, since the upper small connecting rod is connected to the slider table, the large slider is ultimately still driven by a common screw mechanism. The disadvantage is that when load offset occurs, it cannot be corrected; and the transmission form is relatively complicated, which increases the transmission cost and failure probability of the press.

[0007] The patent number CN102306011B applied by the General Research Institute of Mechanical Science is titled "A method for controlling dual-axis synchronization of a linear motion unit". It uses a screw as a transmission system, which is not suitable for the transmission form of a servo press with a faster stroke. The patent number CN102355176A applied by Suzhou Biomedical Engineering is titled "A dual-motor synchronous control system and its implementation method". It uses a rotating motor as a drive device and uses an industrial computer for overall control. Compared with the transmission method driven by a linear motor, this method has a complex transmission structure and has problems such as mechanical clearance.

[0008] In summary, in the scheme of the traditional servo press, after the process curve of the motion controller is generated, there is a transmission delay when it is transmitted to the servo controller, which will affect the performance of the servo motor. In the past, since a single motor controller controls a single motor, if the system requires two motors to work together, the traditional scheme often requires the use of a 2-input 1-output gearbox to achieve mechanical hard connection synchronization. If the two motors directly drive one side of the slider respectively, the two motors need to be softly synchronized. Since the motion controller collects the slider position information separately, there is a transmission delay in the communication process, which can easily cause the inconsistency of the rotation of the two motors. At the same time, if dual motor drive is used, there is still a transmission delay in the communication between the two motor controllers, which will cause the left and right imbalance of the slider when the slider is independently controlled. And because the rotating motor must use cranks, connecting rods and reducers and other mechanisms, there will inevitably be gear gaps. Therefore, it is conventional to add position compensation to the position control loop. Due to the nonlinearity of the gap, it will still affect the synchronous operation accuracy of the slider.

[0009] To this end, the present application designs a new drive system and control device for a servo press to solve the above problems. Summary of the invention

[0010] In order to make up for the deficiencies in the prior art, the present invention provides a novel drive system and control device for a servo press.

[0011] The present invention is achieved through the following technical solutions:

[0012] A novel drive system and control device for a servo press, including an external input signal of the servo press and a human-machine interaction interface, characterized in that;

[0013] The external input signal of the servo press and the human-machine interaction interface are connected to the motion control function module, and the motion control function module is closely connected to the high-level protocol stack COE and the TCP / IP protocol stack. COE and TCP / IP use the instruction parsing module to analyze them into the information required by the motor control state machine. The ucosⅡ embedded operating system is respectively connected to the motor control state machine and the motor control module. The motor control module is connected to the hardware current signal conditioning circuit, position signal conditioning circuit, fault protection and PWM and other functional hardware. The power drive circuit and the six-phase full-bridge IGBT module are connected to the above four hardware circuit modules. The six-phase full-bridge IGBT module is respectively connected to the two three-phase linear motors, and the position sensors of the two three-phase linear motors are respectively connected to the sampling circuit. The lower movers of the two three-phase linear motors are rigidly connected to the slider.

[0014] Furthermore, in order to better implement the present invention, the human-computer interaction interface includes buttons, knobs and selection switches on the operation panel; the ucosⅡ embedded operating system is also connected to a fault monitoring and redundant safety module.

[0015] Furthermore, in order to better realize the present invention, the ucosⅡ embedded operating system selects Ti's dual-core processor TMS320F28388D as the main control chip, is equipped with storage chips DRAM and NORFLASH, and is equipped with a real-time clock, EEPROM, and a crystal oscillator chip on the main control board; the external input signal of the servo press includes interface information read from each sub-module interface, and the specific module interfaces include CAN interface, RJ45 network port, RS232 interface, RS485 interface and IO interface, and the specific module interface information is single, continuous, manual, mold change, standby mode selection, handwheel, speed selection, return, slider down and slider up, emergency stop, servo motor ready; the human-computer interaction interface also interacts with the motion control function module through the RS485 interface. After the motion control function module analyzes the interface information of each module, the corresponding data information is directly parsed into the data content of the corresponding COE protocol stack and TCP / IP protocol stack and puts it into the corresponding memory.

[0016] Furthermore, in order to better realize the present invention, the instruction parsing module is connected and interacts with specific motor control instructions through COE and TCP / IP protocol stack. The motor control state machine switches different states according to the received motor control instructions. The motor control state machine is designed based on the ucosⅡ embedded operating system. At the same time, the embedded operating system also undertakes multiple functions such as task scheduling, task allocation, resource allocation, memory management and real-time kernel management. The embedded operating system outputs the results of the motor task calculation to the motor control module respectively. At the same time, the embedded operating system also runs multiple functional modules at the same time, including a heartbeat monitoring module, an operating system operation abnormality module and an algorithm software abnormality module.

[0017] Furthermore, in order to better realize the present invention, the motor control module includes common functional modules of the motor control algorithm, specifically overmodulation, magnetic weakening, vector control, magnetic field orientation, angle calculation, current conversion, and regulator. The information required for motor control comes from the output of the underlying current conditioning circuit, the output of the position conditioning circuit, and the fault protection output, and the motor control module result is output to the PWM function. The PWM function is output to the linear motor through the underlying hardware driving circuit and two three-phase full-bridge IGBT modules. The linear motor drives the slider through a rigid connection to move up and down.

[0018] Furthermore, in order to better implement the present invention, the position of the mover of the linear motor is collected by a motor position sensor and fed back to the position conditioning module through an acquisition circuit.

[0019] Furthermore, in order to better implement the present invention, the motion control function module generates a process curve and transmits the process curve to the motor control module, and the motor control module includes a first linear motor control module and a second linear motor control module.

[0020] Furthermore, in order to better realize the present invention, in the first linear motor control module, in a certain PWM cycle, a certain point of the real-time process curve is used as a given input as a position input given value, and the first linear motor position sensor is used as a position feedback value, and the difference between the two positions is subtracted as the input of the first position control loop; the first position control loop contains a PI regulator, and the output of the position control loop is stored in the address A of the shared memory. By utilizing the synchronous clock and inter-core communication mechanism, the output of the first motor position control loop can be quickly read through the shared memory address A and transmitted to the position transformation module, and the second linear motor position feedback value is synchronized with the output of the position transformation module. The value obtained by subtracting the given value of the process curve from the difference B is used as the input of the second position control loop. The outputs of the first position control loop and the second position control loop are used as the inputs of the first speed control loop and the second speed control loop respectively. The outputs of the first speed control loop and the second speed control loop are used as the inputs of the first torque control loop and the second torque control loop. The outputs of the first torque control loop and the second torque control loop are used as the inputs of the first vector control and the second vector control. The PWM waveforms calculated in the first vector control and the second vector space are output through two three-phase full-bridge IGBTs with high voltage and high current, and finally drive the first linear motor and the second linear motor to operate.

[0021] The beneficial effects of the present invention are:

[0022] The present invention solves the following problems:

[0023] (1) The gears are removed, gear clearance is eliminated, and the dual linear motors are controlled synchronously and independently, achieving a real-time feedback closed loop, improving the slide control accuracy of the press, and solving the problem of left and right slide eccentricity;

[0024] (2) It eliminates the transmission delay from the motion control function to the servo controller, eliminates the transmission communication delay between servo controllers, improves the stability of system operation, and solves the task scheduling problem and soft synchronization problem in the process of independent synchronous control of two motors;

[0025] (3) Compared with the traditional control methods used in previous patents and industries, the motion control function and two motor controls are integrated into a new drive control system, which adopts a new hardware and software architecture solution, greatly reduces the cost and improves the power density of the system. It also integrates COE and TCPIP network communication protocols for easy expansion.

[0026] The present invention uses an embedded operating system to implement real-time management of two motor controls and other functions such as fault monitoring, redundant safety, etc. It is necessary to realize data exchange between the two motor controllers without time difference to complete the synchronous position closed-loop control in the DSP. Since the present invention uses an integrated servo drive control system of dual linear motors, the communication efficiency between the motion controller and the two servo controllers is greatly shortened, and the original communication delay of more than 100ms is eliminated. At the same time, the accuracy of the control system is also improved, and the repeat positioning accuracy of the bottom dead point of the slider can reach 0.005mm. The integrated servo drive system of the present invention can increase the power density of the entire system by 30%.

[0027] From a price comparison, since the original motion controller is eliminated, the cost of motion control and related plug-in cables is saved. Since motion controllers are generally more expensive, the cost performance is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 A novel control system for a servo press of the present invention;

[0029] Figure 2 The motor control state machine of the present invention;

[0030] Figure 3 This is the independent synchronous control strategy of the dual linear motors of the present invention.

[0031] In the figure,

[0032] 1. The first linear motor, 2. The first linear motor position sensor, 3. The second linear motor, 4. The second linear motor position sensor, 5. The slider. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the accompanying drawings here can be arranged and designed in various different configurations.

[0034] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative work are within the scope of protection of the present invention.

[0035] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0036] In the description of the present invention, it should be noted that the terms "middle", "upper", "lower", "horizontal", "inner", "outer", etc. indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, or the positions or positional relationships in which the product of the invention is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0037] In addition, the terms "horizontal", "vertical" and the like do not mean that the components are required to be absolutely horizontal or suspended, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0038] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection. It can be a mechanical connection or an electrical connection. It can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] Some embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0040] like Figure 1As shown, the specific embodiment of the present invention is a new type of drive system and control device for a servo press, which specifically includes an external input signal of the servo press and a human-machine interaction interface, and the human-machine interaction interface includes buttons, knobs and selection switches on the operation panel. The external input signal is connected to the motion control function module, and the motion control function module is closely connected to the high-level protocol stack COE and TCP / IP protocol stack. COE and TCP / IP use the instruction parsing module to analyze it into the information required by the motor control state machine. The ucosⅡ embedded operating system is connected to the motor control state machine and the motor control module respectively. The motor control module is connected to the hardware current signal conditioning circuit, position signal conditioning circuit, fault protection and PWM and other functional hardware. The power drive circuit and the six-phase full-bridge IGBT module are connected to the above four hardware circuit modules, and other functions include fault monitoring and redundant safety modules. The six-phase full-bridge IGBT module is connected to two three-phase linear motors respectively. The position sensors of the two three-phase linear motors are connected to the sampling circuit respectively. The lower movers of the two three-phase linear motors are rigidly connected to the slider.

[0041] This embodiment uses Ti's dual-core processor TMS320F28388D as the main control chip, equipped with large-capacity storage chips DRAM and NORFLASH. And on the main control board are chips such as real-time clock, EEPROM, crystal oscillator, etc. The external input signal includes information read from each submodule, and the specific module interfaces include CAN interface, RJ45 network port, RS232 interface, RS485 interface and IO interface, etc. The specific module interface information is single, continuous, manual, mold change, standby and other mode selections, handwheel, speed selection, return, slider down and slider up, emergency stop, servo motor ready, etc. At the same time, the human-computer interaction interface also interacts with the motion control function module through the RS485 interface. After analyzing the above interface information, the motion control function module directly parses the corresponding data information into the data content of the corresponding COE protocol stack and TCP / IP protocol stack and puts it into the corresponding memory. The instruction parsing module can connect and interact with specific motor control instructions through COE and TCP / IP protocol stacks. The motor control state machine switches between different states according to the motor control instructions received, such as Figure 2 shown.

[0042] The motor control state machine of this embodiment is designed on the basis of the uCosⅡ embedded operating system. At the same time, the embedded operating system also undertakes multiple functions such as task scheduling, task allocation, resource allocation, memory management and real-time kernel management. The embedded operating system outputs the results of the motor task calculation to the motor control module respectively. At the same time, the embedded operating system also runs multiple functional modules at the same time, including a heartbeat monitoring module, an operating system operation abnormality module and an algorithm software abnormality module. The motor control module includes common functional modules of the motor control algorithm, specifically overmodulation, weak magnetic field, vector control, magnetic field orientation, angle calculation, current conversion, regulator, etc. The information required for motor control comes from the output of the underlying current conditioning circuit, the output of the position conditioning circuit, and the fault protection output, and the results of the motor control module are output to the PWM function. The PWM function is output to the linear motor through the underlying hardware drive circuit and two three-phase full-bridge IGBT modules. The linear motor drives the slider through a rigid connection to move up and down. The position of the linear motor's mover is collected by the motor position sensor and fed back to the position conditioning module through the acquisition circuit. Since the present invention uses an embedded operating system to implement real-time management of the two motor controls and other functions such as fault monitoring, redundant safety, etc., it is necessary to achieve data exchange between the two motor controllers without time difference to complete the synchronous position closed-loop control in the DSP. Since the present invention uses an integrated servo drive control system of dual linear motors, the communication efficiency between the motion controller and the two servo controllers is greatly shortened, and the original communication delay of more than 100ms is eliminated. At the same time, the accuracy of the control system is also improved, and the repeat positioning accuracy of the lower dead point of the slider can reach 0.005mm. The integrated servo drive system of the present invention can increase the power density of the entire system by 30%.

[0043] like Figure 3As shown, for the dual-motor synchronous control in the servo press, this embodiment divides the control process into two control parts. The motion control function module generates a process curve and transmits the process curve to the motor control module. The frequency of the motor control module is generally 10KHz, and the period is 0.1ms. The control loop surrounded by the larger dotted square is the first linear motor control module. In a certain PWM cycle, a certain point of the real-time process curve is used as a given input as a position input given value, and the first linear motor position sensor is used as a position feedback value. The difference between the two positions is subtracted as the input of the first position control loop; the first position control loop contains a PI regulator, and the output of the position control loop is stored in the address A of the shared memory. Using the synchronous clock and inter-core communication mechanism, the output of the first motor position control loop can be quickly read through the shared memory address A and transmitted to the position transformation module. The second linear motor position feedback value is subtracted from the output of the position transformation module to obtain the difference B. The value obtained by subtracting the given value of the process curve from the difference B is used as the input of the second position control loop. The outputs of the first position control loop and the second position control loop are used as the inputs of the first speed control loop and the second speed control loop respectively, and the outputs of the first speed control loop and the second speed control loop are used as the inputs of the first torque control loop and the second torque control loop. The outputs of the first torque control loop and the second torque control loop are used as the inputs of the first vector control and the second vector control. The PWM waveforms calculated in the first vector control and the second vector space are output through two three-phase full-bridge IGBTs with high voltage and high current, and finally drive the linear motor to operate.

[0044] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the present invention by ordinary technicians in the field should be included in the scope of the claims of the present invention as long as they do not depart from the spirit and scope of the technical solution of the present invention.

Claims

1. A novel drive system and control device for a servo press, including an external input signal of the servo press and a human-machine interaction interface, characterized in that: The external input signal of the servo press and the human-machine interaction interface are connected to the motion control function module, the motion control function module is closely connected to the high-level protocol stack COE and the TCP / IP protocol stack, COE and TCP / IP use the instruction parsing module to analyze it into the information required by the motor control state machine, the ucosⅡ embedded operating system is respectively connected to the motor control state machine and the motor control module, the motor control module is connected to the hardware current signal conditioning circuit, position signal conditioning circuit, fault protection and PWM, the power drive circuit and the six-phase full-bridge IGBT module are connected to the above-mentioned four hardware circuit modules of current signal conditioning circuit, position signal conditioning circuit, fault protection and PWM, the six-phase full-bridge IGBT module is respectively connected to two three-phase linear motors, the position sensors of the two three-phase linear motors are respectively connected to the sampling circuit, and the lower movers of the two three-phase linear motors are rigidly connected to the slider (5); The human-machine interaction interface includes buttons, knobs and selection switches on the operation panel; the ucosⅡ embedded operating system is also connected to a fault monitoring and redundant safety module; The ucosⅡ embedded operating system uses Ti's dual-core processor TMS320F28388D as the main control chip, equipped with storage chips DRAM and NORFLASH, and equipped with a real-time clock, EEPROM, and crystal oscillator chip on the main control board; The external input signal of the servo press includes interface information read from each sub-module interface, and the specific module interfaces include CAN interface, RJ45 network port, RS232 interface, RS485 interface and IO interface. The specific module interface information is single, continuous, manual, mold change, standby mode selection, handwheel, fast or slow selection, return, slider down and slider up, emergency stop, servo motor ready; the human-computer interaction interface also interacts with the motion control function module through the RS485 interface. After analyzing the interface information of each module, the motion control function module directly parses the corresponding data information into the data content of the corresponding COE protocol stack and TCPIP protocol stack and puts it into the corresponding memory.

2. The novel drive system and control device of the servo press according to claim 1, characterized in that: The instruction parsing module is connected and interacts with specific motor control instructions through COE and TCPIP protocol stack. The motor control state machine switches different states according to the received motor control instructions. The motor control state machine is designed based on the ucosⅡ embedded operating system. At the same time, the embedded operating system also undertakes multiple functions such as task scheduling, task allocation, resource allocation, memory management and real-time kernel management. The embedded operating system outputs the results of the motor task calculation to the motor control module respectively. At the same time, the embedded operating system also runs multiple functional modules at the same time, including a heartbeat monitoring module, an operating system operation abnormality module and an algorithm software abnormality module.

3. The novel drive system and control device of the servo press according to claim 2, characterized in that: The motor control module includes common functional modules of the motor control algorithm, specifically overmodulation, magnetic weakening, vector control, magnetic field orientation, angle calculation, current conversion, and regulator. The information required for motor control comes from the output of the underlying current signal conditioning circuit, the output of the position signal conditioning circuit, and the fault protection output. The motor control module result is output to the PWM function, and the PWM function is output to the linear motor through the underlying hardware drive circuit and two three-phase full-bridge IGBT modules. The linear motor drives the slider through a rigid connection to move up and down.

4. The novel drive system and control device of the servo press according to claim 3, characterized in that: The position of the mover of the linear motor is collected by a motor position sensor and fed back to a position signal conditioning circuit through a collection circuit.

5. The novel drive system and control device of the servo press according to claim 1, characterized in that: The motion control function module generates a process curve and transmits the process curve to the motor control module. The motor control module includes a first linear motor control module and a second linear motor control module.

6. The novel drive system and control device of the servo press according to claim 5, characterized in that: In the first linear motor control module, in a certain PWM cycle, a certain point of the real-time process curve is used as a given input as a position input given value, and the first linear motor position sensor is used as a position feedback value. The difference between the two positions is subtracted as the input of the first position control loop; the first position control loop contains a PI regulator, and the output of the position control loop is stored in the address A of the shared memory. By using the synchronous clock and inter-core communication mechanism, the output of the first motor position control loop can be quickly read through the shared memory address A and transmitted to the position transformation module. The second linear motor position feedback value is subtracted from the output of the position transformation module to obtain the difference B, and the process curve The value obtained by subtracting the given value from the difference value B is used as the input of the second position control loop. The outputs of the first position control loop and the second position control loop are used as the inputs of the first speed control loop and the second speed control loop respectively. The outputs of the first speed control loop and the second speed control loop are used as the inputs of the first torque control loop and the second torque control loop. The outputs of the first torque control loop and the second torque control loop are used as the inputs of the first vector control and the second vector control. The PWM waveforms calculated by the first vector control and the second vector control are output through two three-phase full-bridge IGBTs with high voltage and high current, and finally drive the first linear motor (1) and the second linear motor (3) to operate.

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