CN112064186A - Upper computer system for adjusting fabric density of computerized flat knitting machine and adjusting method - Google Patents

Abstract

The invention discloses a computerized flat knitting machine fabric density adjusting upper computer system which comprises an upper computer and an ARM controller which are connected through a CAN bus, wherein the CAN transceiver is a bridge for communicating the upper computer and the ARM controller, the CAN transceiver converts transmission data into electric signals to be sent out, the ARM controller is sequentially connected with a motor driving module, a stepping motor, a density adjusting module and a Hall sensor, the Hall sensor is also connected with the ARM controller, and a chip memory module is connected with the ARM controller. The invention also discloses an adjusting method of the computerized flat knitting machine fabric density adjusting upper computer system. The invention solves the problems of poor fabric density adjusting precision and incomplete adjusting function in the prior art.

Description

Upper computer system for adjusting fabric density of computerized flat knitting machine and adjusting method

Technical Field

The invention belongs to the technical field of fabric density adjustment, and particularly relates to a computerized flat knitting machine fabric density adjustment upper computer system and an adjustment method.

Background

At present, because high-grade knitwear such as sweater and the like has expensive raw materials and high requirements on process processing, cost waste is caused when errors (such as breakage easily occurs to wool yarns with low strength and broken holes and broken ends of knitted fabrics) occur in the knitting process, and density adjustment is one of important factors among a plurality of factors influencing knitting quality. The density regulating mechanism changes the fabric density by changing the depth of the yarn bending, and the reasonable, high-precision and advanced mechanism can adapt to the density of various knitted fabrics with different tissues, so that the density of the fabric is uniform, the machine runs reliably, and the fabric with high technical content is woven. The currently developed computerized flat knitting machine control systems are numerous, the German STOLL and the Japanese Islamic have better foreign properties, the equipment performance is reliable, but the human-computer interaction interface is not friendly enough; the Yuxiang of Zhang Jia gang and Tianyuan of Nanjing exist in China, and the Yuanhang Yuan mainly produces middle and low-end products. The design method of upper computer software with ARM-Linux as a platform is provided in 'design of upper computer of computerized flat knitting machine based on Qt' by Haoqing in China. A design method taking a PC104 module and WinCE as a platform is provided in 'design of software of an upper computer of a full-automatic computerized flat knitting machine' by domestic old scenery waves, the system adopts a two-stage control structure of the PC104 upper computer and an FPGA lower computer, and the software is compiled by adopting an Embedded Visual C + + tool in WinCE5.0 environment. The designs are designed aiming at an upper computer of a computerized flat knitting machine, the special upper computer design aiming at the density adjusting mechanism is rarely carried out, the interface of the whole machine is complex, the operation is complicated, the fabric density data can not be displayed in detail, the parameter of the fabric density adjusting mechanism can not be mastered more accurately, and the functions are not perfect.

Disclosure of Invention

The invention aims to provide an upper computer system for adjusting fabric density of a computerized flat knitting machine, which solves the problems of poor fabric density adjusting precision and incomplete adjusting function in the prior art.

The invention also aims to provide an adjusting method of the upper computer system for adjusting the fabric density of the computerized flat knitting machine.

The invention adopts a first technical scheme that the upper computer system for regulating the fabric density of the computerized flat knitting machine comprises an upper computer and an ARM controller which are connected through a CAN bus, wherein the CAN transceiver is a bridge for communicating the upper computer and the ARM controller, the CAN transceiver converts transmission data into electric signals to be sent out, the ARM controller is sequentially connected with a motor driving module, a stepping motor, a density regulating module and a Hall sensor, the Hall sensor is also connected with the ARM controller, and a chip memory module is connected with the ARM controller.

The first technical aspect of the invention is also characterized in that,

the ARM controller is ARM Cortex-M0's LPC11C24 control chip, and the ARM controller has integrateed the TJF1051 CAN transceiver, motor drive module adopts BD63860 driver chip, chip memory module is the inside integrated memory of ARM controller, the step motor model is the two-phase four-beat hybrid of 57BYG250 series.

The density adjusting module has the specific structure that: the computer flat knitting machine comprises a gear set consisting of a gear Z1, a gear Z2 and a gear Z3, wherein a stepping motor drives the gear set to rotate, a coaxial cam is driven by the rotation of the gear Z3 to move, so that meshes embedded in an inner groove of the cam are linearly displaced, and meanwhile, a mesh triangle connected with the other end of the meshes is driven to slide in a mesh chute; the variable quantity of the fabric density is realized by detecting the pull-down displacement of the yarns through the Hall sensor, the output of the sensor is fed back to the controller through a series of conversions, and the controller outputs control pulses to realize the accurate control of the stepping motor.

The four Hall sensors are distributed on four quadrant points around the camshaft sleeve at intervals of 90 degrees, and the four distributed quadrant points are circles with the radius of 1.1 mm.

The second technical scheme adopted by the invention is that the adjusting method of the upper computer system for adjusting the fabric density of the computerized flat knitting machine is implemented according to the following steps:

step 1, an upper computer enables a CAN transceiver to send control data to an ARM controller in an interrupted mode through a CAN bus, wherein the control data comprises a motor rotation direction, a motor rotation speed, motor zeroing operation data, a current position and an absolute position of a mesh;

step 2, after the ARM controller successfully receives the data, analyzing and processing the control data, and then transmitting the control data to the motor driving module to enable the stitch motor to act according to the appointed direction, speed and position, and the rotation of the motor drives the density adjusting module to move;

step 3, the motor drives the cam coaxially connected with the gear Z3 to do rotary motion through the mechanical transmission of the gear set, and simultaneously, the stitch embedded in the inner groove of the cam does linear displacement and simultaneously drives the stitch triangle connected with the other end of the stitch to uniformly slide in the chute of the bottom plate of the handpiece;

step 4, after the stitch position is adjusted in place, the head of the computerized flat knitting machine moves along the running direction, when the head moves to the position of the selected knitting needle to be knitted, the drop-down displacement of the knitting needle is changed due to the change of the stitch position, so that the depth of the yarn hooked and pulled by the knitting needle, namely the yarn bending depth is changed, and the change of the fabric density is realized;

and 5, changing the yarn bending depth, acquiring the yarn bending depth through detection and acquisition of a Hall sensor, feeding back the acquired data to an ARM controller through position conversion and analog-to-digital conversion, generating an adjusting variable by the ARM controller, and continuously adjusting the degree of the stepping motor according to the variable until the stepping motor is adjusted in place.

The second technical aspect of the present invention is also characterized in that,

in the step 1, the upper computer enables the CAN transceiver to send control data to the ARM controller in an interrupted mode through the CAN bus, and the method specifically comprises the following steps:

the upper computer sends data to the ARM controller in an interrupt mode, when detecting that an interrupt bit has a corresponding level, the upper computer enters a CAN interrupt receiving link, the ARM receives CAN bus messages and sends CAN messages to generate interrupts, firstly, whether the messages are error messages or not is judged, if the messages are error messages, the messages are directly deleted and returned to wait for the interrupts, if the messages are useful messages, message object numbers are read, the messages are read to an interface register, first buffer Busy bits of the messages are judged, if the messages are 0, the messages are directly stored in the first buffer, if the messages are 1, the Busy bits of the second buffer are judged, if the messages are 0, the second buffer exists, if the messages are 1, the messages are ignored, the messages are returned to wait for the interrupts and are sent again.

The feedback control algorithm in step 5 is as follows:

the method is characterized in that the yarn bending depth is measured and returned by a Hall sensor and is used for analyzing and comparing with a given value, the control deviation is calculated, the closed-loop control of the system is realized, a fuzzy logic rule is added on the basis of the original classical PID closed-loop control algorithm to form a fuzzy PID control algorithm, the control performance of a fabric density adjusting mechanism is improved, and more accurate control is realized.

The invention has the beneficial effects that the upper computer system and the adjusting method for adjusting the fabric density of the computerized flat knitting machine aim at the situation that the upper computer of the computerized flat knitting machine at home and abroad CAN not reflect the detailed functional parameters of the fabric density adjusting system of the flat knitting machine in detail. The invention adopts multi-thread design to realize multi-task parallel processing of the system. The application result proves that compared with the traditional computerized flat knitting machine upper computer software, the method is simple to operate, more specific in function and strong in real-time performance, more humanized user interface experience is realized, the lower computer can be accurately and quickly controlled, the running state is reflected, and the performance index of the method is superior to that of domestic similar products.

Drawings

FIG. 1 is a block diagram of a fabric density adjustment system;

FIG. 2 is a schematic diagram of a fabric density adjustment mechanism;

FIG. 3 is a CAN interrupt handling block diagram;

FIG. 4 is a schematic diagram of a Hall sensor distribution;

FIG. 5(a) is a view of the initial state of the height of the stitch cam;

fig. 5(b) is a view showing the effective state of the mesh triangle height.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention discloses a computerized flat knitting machine fabric density adjusting upper computer system which is structurally shown in figures 1-2 and comprises an upper computer and an ARM controller which are connected through a CAN bus, wherein a CAN transceiver is a bridge for communicating the upper computer and the ARM controller, the CAN transceiver converts transmission data into electric signals to be sent out, the ARM controller is sequentially connected with a motor driving module, a stepping motor, a density adjusting module and a Hall sensor, the Hall sensor is also connected with the ARM controller, and a chip memory module is connected with the ARM controller.

The ARM controller is ARM Cortex-M0's LPC11C24 control chip, and the ARM controller has integrateed the TJF1051 CAN transceiver, motor drive module adopts BD63860 driver chip, chip memory module is the inside integrated memory of ARM controller, the step motor model is the two-phase four-beat hybrid of 57BYG250 series.

The density adjusting module has the specific structure that: the computer flat knitting machine comprises a gear set consisting of a gear Z1, a gear Z2 and a gear Z3, wherein a stepping motor drives the gear set to rotate, a coaxial cam is driven by the rotation of the gear Z3 to move, so that meshes embedded in an inner groove of the cam are linearly displaced, and meanwhile, a mesh triangle connected with the other end of the meshes is driven to slide in a mesh chute; the variable quantity of the fabric density is realized by detecting the pull-down displacement of the yarns through the Hall sensor, the output of the sensor is fed back to the controller through a series of conversions, and the controller outputs control pulses to realize the accurate control of the stepping motor.

As shown in fig. 4, 5(a) to 5(b), four hall sensors are distributed on four quadrant points around the camshaft sleeve at intervals of 90 degrees, and the four distributed quadrant points are circles with the radius of 1.1 mm.

A method for adjusting an upper computer system for adjusting fabric density of a computerized flat knitting machine is shown in a flow chart of 3 and is implemented according to the following steps:

step 1, an upper computer enables a CAN transceiver to send control data to an ARM controller in an interrupted mode through a CAN bus, wherein the control data comprises a motor rotation direction, a motor rotation speed, motor zeroing operation data, a current position and an absolute position of a mesh;

in the step 1, the upper computer enables the CAN transceiver to send control data to the ARM controller in an interrupted mode through the CAN bus, and the method specifically comprises the following steps:

the upper computer sends data to the ARM controller in an interrupt mode, when detecting that an interrupt bit has a corresponding level, the upper computer enters a CAN interrupt receiving link, the ARM receives CAN bus messages and sends CAN messages to generate interrupts, firstly, whether the messages are error messages or not is judged, if the messages are error messages, the messages are directly deleted and returned to wait for the interrupts, if the messages are useful messages, message object numbers are read, the messages are read to an interface register, first buffer Busy bits of the messages are judged, if the messages are 0, the messages are directly stored in the first buffer, if the messages are 1, the Busy bits of the second buffer are judged, if the messages are 0, the second buffer exists, if the messages are 1, the messages are ignored, the messages are returned to wait for the interrupts and are sent again.

Step 2, after the ARM controller successfully receives the data, analyzing and processing the control data, and then transmitting the control data to the motor driving module to enable the stitch motor to act according to the appointed direction, speed and position, and the rotation of the motor drives the density adjusting module to move;

step 3, the motor drives the cam coaxially connected with the gear Z3 to do rotary motion through the mechanical transmission of the gear set, and simultaneously, the stitch embedded in the inner groove of the cam does linear displacement and simultaneously drives the stitch triangle connected with the other end of the stitch to uniformly slide in the chute of the bottom plate of the handpiece;

step 4, after the stitch position is adjusted in place, the head of the computerized flat knitting machine moves along the running direction, when the head moves to the position of the selected knitting needle to be knitted, the drop-down displacement of the knitting needle is changed due to the change of the stitch position, so that the depth of the yarn hooked and pulled by the knitting needle, namely the yarn bending depth is changed, and the change of the fabric density is realized;

and 5, changing the yarn bending depth, acquiring the yarn bending depth through detection and acquisition of a Hall sensor, feeding back the acquired data to an ARM controller through position conversion and analog-to-digital conversion, generating an adjusting variable by the ARM controller, and continuously adjusting the degree of the stepping motor according to the variable until the stepping motor is adjusted in place.

The feedback control algorithm in step 5 is as follows:

the method is characterized in that the yarn bending depth is measured and returned by a Hall sensor and is used for analyzing and comparing with a given value, the control deviation is calculated, the closed-loop control of the system is realized, a fuzzy logic rule is added on the basis of the original classical PID closed-loop control algorithm to form a fuzzy PID control algorithm, the control performance of a fabric density adjusting mechanism is improved, and more accurate control is realized.

The functions of each part of the invention are introduced as follows:

1. general overview of Fabric Density Conditioning System

The adjustment of the fabric density refers to the adjustment of the tightness degree of a knitted fabric coil structure, and the stitch depth is completed by driving a cam through a control stitch motor (namely a stepping motor for adjusting the density) so as to drive a slider to drive a stitch to slide in a 45-degree chute on a bottom plate of a machine head, thereby driving a density needle pressing triangle and a needle raising triangle to move. The system mainly judges whether density adjustment is in place or not by controlling the absolute position (namely the current position) and the relative position (the distance moved to a target) of the density adjustment.

The overall system operates as follows: when the fabric density is adjusted and controlled through the upper computer, the upper computer sends control data to an LPC11C24 control chip based on ARM Cortex-M0 in a CAN bus mode, the main control module sends the data to a motor driving module adopting a BD63860 driving chip after analyzing and processing the data so that a stitch motor acts according to indication, when the stepping motor receives a control instruction, the motor rotates by a certain step angle according to a pulse signal, a sliding block nested in an equal-lift curve cam inner groove drives a stitch to slide uniformly along a machine head bottom plate sliding groove through a transmission device, the density of the fabric is changed by adjusting the yarn bending depth, and meanwhile, positions of all parts are measured and sent back through all sensors for analysis and comparison. And storing the pattern data and the measurement data, storing interruption information, timely making shutdown preparation when abnormality is found, and prompting and displaying in an upper computer. A fabric density adjusting system is shown in figure 1.

Fig. 4 shows a distribution diagram of the hall sensor. The four Hall position sensors X1, X2, Y1 and Y2 are distributed on four quadrant points of an R1.1mm circle at intervals of 90 degrees and are positioned on a circuit board at the tail part of the motor. After the data acquisition of the Hall sensor, the angular displacement variable quantity of the motor can be obtained. And feeding back the current position of the slide block to the controller through calculation. The speed feedback of the motor adopts a photoelectric encoder manufactured by ohm dragon company, and the model is E6B2-CWZ 6C. It outputs square wave signals with different frequencies according to different rotating speeds of the motor. The signal has two paths, namely CHAN1 and CHAN2, the phase angle difference between the two paths is 90 degrees, when the motor rotates forwards, the CHAN1 advances, and when the motor rotates backwards, the CHAN1 lags; the stitch cam is shown in the following fig. 5, the initial height in fig. 5(a) is at the height when the stitch is lifted, and the electric control value of the stitch motor is 0 at the moment, namely the highest position of the lifted stitch; the stitch triangle is in the stitch effective state as in fig. 5(b), and is between the height and the initial height when the stitch is pressed, and the electric control value of the stitch motor is shown as '649', namely, the lowest part of the stitch is pressed; the height of the mesh triangle is continuously adjustable between the lower graphs (a) and (b), the electric control value of the mesh motor is in the [0,649] interval, and the larger the value is, the looser the fabric is.

The CAN interruption is the reception of CAN messages. When the system is interrupted, the CAN message is inquired, and only the set memory is inquired, and when the set memory has CAN message communication, the CAN message CAN be analyzed according to the established CAN protocol, and then corresponding action is executed.

And (3) CAN application layer protocol formulation:

the CAN supports 2 message formats, which differ only in the length of the Identifier (ID) of the arbitration segment, with a standard format of 11 bits and an extended format of 29 bits. According to the method, a CAN control protocol is modified according to the definition of a stepping motor used by a encryption system, and 29-bit extended CAN message formats are adopted, namely ID 0-ID 28. Defining the receiving address bits for the stepping motor from the 7 bits of ID22 to ID28, which can satisfy the control of 128 motors; defining ID21 as global instruction bit, that is, when the bit of a CAN message is 1, the message is received by all receivers; defining ID 0-ID 3 as 4 control bits as control instruction bits of the stepping motor; defining IDs 4-ID 11 as 8-bit data bits for indicating the rotation steps of the stepping motor; ID 12-ID 20 are defined as reserved bits for future functional extensions.

Designing a CAN driving process:

CAN initialization:

the initialization mainly comprises 3 parts: and the configuration register enables the CAN clock and configures the message object.

The LPC11C24 chip adopted by the invention has 32 message objects, and the message objects 1-4 are used as receiving messages, and the message object 5 is used as sending messages. The 4 received message objects may constitute a receive FIFO buffer. When configuring the message objects, 5 message objects that are active need to be configured separately, and the rest of the message objects that are not used need to be set as invalid (the MSGVAL bit is set to "0").

In the interface register configuration, the mask, arbitration, control, and data fields of one of the two registers need only be set to the desired values. In order to reduce the utilization rate of the CPU, the receiving address of the CAN message is filtered through the shielding and arbitration bit.

Writing to the corresponding IF1 command request register may load IF1 message buffer data into the corresponding message object. IF the IF1 register is transferring data with the message object, the message handler will set the BUSY bit of the associated command register to "1". After the data transfer is complete, the BUSY bit is again set to "0".

CAN message transmission and reception are similar, but the values in the registers are different, and are not described in detail herein.

CAN interruption processing:

the priority of 1-32 message objects is gradually reduced, and when the RAM receives the message, the RAM generates interruption according to the priority of the message objects stored in the message. When a message interrupt is generated, the first step is to eliminate the error interrupt. When the interrupt generated by the message object is determined, firstly, the number of the interrupt message object is read, then, data is read from the message object by using the other interface register IF2, and finally, the BUSY bit of two message buffers in the RAM is judged, IF the BUSY bit is '0', the data is idle, the data acquired by the interface register IF2 is put into the idle buffer, and the BUSY bit in the buffer is set to be '1', so that the message is successfully received. The CAN interrupt handling block diagram is shown in fig. 3. The 2 message RAM buffers are arranged to prevent the next CAN message interrupt caused by the fact that the previous CAN command is not processed. Therefore, when the last CAN message instruction stored in the buffer 1 is not processed, the next instruction CAN be stored in the CAN message buffer 2 and executed after the execution in the buffer 1 is finished.

Communication of an upper computer:

in the fabric density adjusting mechanism, a plurality of parameters are controlled and monitored by an upper computer, and the parameters mainly comprise stepping motor zeroing operation, controller parameters, absolute and relative positions of the stepping motor, the steering direction of the motor, acceleration and deceleration and acceleration and deceleration coefficients of the motor, current and voltage, various compensation factors and the like. According to the different refresh frequencies of the parameters in the system, the address codes with different priority levels of the parameters are configured in the CAN application layer protocol, and according to the address codes of the parameters, the parameters CAN be configured and monitored in real time. The parameter group is defined in consideration of the utilization rate of the CAN bus and the reduction of the error rate of the system, different functional parameters form the parameter group, and the parameters with close refreshing frequency are sent in one parameter group as much as possible, so that the number of times of sending node information CAN be reduced, and the utilization rate of the bus is improved. For example, current and voltage monitoring, the values of which may be placed in a parameter set, the absolute and relative position of the stepper motor may be placed in a parameter set, and so on. The determination of the fabric density adjusting position is represented by two positions of a stepping motor, the system adopts a two-phase type mixed stepping motor, the stepping angle is 0.45 degrees, the electric control value of the motor for degree adjustment is in a [0,649] interval, the degree is continuously adjustable in the interval, and the larger the value is, the looser the fabric is. Suppose the upper computer sends a command to adjust the fabric density such that the stitch motor electrical control reaches 432, and the absolute position of the stepping motor monitoring return is 112, so the relative position required by the stepping motor is 320. In the protocol, the data field of the CAN communication message is agreed to be composed of 8 bytes, each Byte has two characters, the front character represents the high 4 bits, the rear character represents the low 4 bits, the Byte1 is the low Byte, and the Byte2 is the high Byte. The protocol specifies that the stepping motor position parameters are sent or received simultaneously, absolute position data is placed in the first byte and the second byte of the message data segment, relative position data is placed in the third byte and the fourth byte of the message data segment, the high byte represents the high position of the motor position value, and the low byte represents the low position of the motor position value. By simple calculation, the absolute position of the stepper motor is 112, represented by hexadecimal numbers 0070, and the relative position of the stepper motor is 320, represented by hexadecimal numbers 0140. The data segment in the message should be 7000400100000000 as specified by the protocol.

The experimental result shows that when the encryption system is controlled by adopting the classical PID algorithm, the adjusting time is 4.2s, and the requirement cannot be met due to large overshoot; and the fuzzy PID algorithm is adopted for control, so that the adjusting time is 1.7s, overshoot is avoided, and the requirements are completely met. (System design requires accomplishment of an adjustment within 2s without overshoot at the same time)

The results of comparing the control algorithm with the classical PID control algorithm are shown in Table 1-1.

TABLE 1-1 control algorithm COMPARATIVE TABLE

It can be clearly seen from the table that the fuzzy PID control algorithm designed for the novel improved fabric density adjusting mechanism is superior to the classical PID algorithm, and the design result meets the system control requirement.

The upper computer is an important component of a fabric density adjusting control system of the computerized flat knitting machine, can accurately and timely reflect the adjusting condition of a stitch motor, can conveniently change operation parameters, and realizes real-time control of a fabric adjusting mechanism. Through online debugging of the whole fabric density adjusting system, from the test result, the requirements of real-time performance and stability of the fabric density adjusting system are well met, and meanwhile the requirements of most users can be met. The design idea and the implementation method of the invention have important significance for the quantitative production of the high-performance computerized flat knitting machine fabric density adjusting system.

Claims (7)

1. The utility model provides a computerized flat knitting machine fabric density adjusts host computer system, a serial communication port, include host computer and ARM controller through CAN bus connection, the CAN transceiver is the bridge of host computer and ARM controller communication, the CAN transceiver turns into the signal of telecommunication with transmission data and sends away, the ARM controller in proper order again with motor drive module, step motor, density adjusting module, hall sensor is connected, hall sensor still is connected with the ARM controller simultaneously, chip memory module and ARM controller interconnect.

2. The upper computer system for adjusting the fabric density of the computerized flat knitting machine according to claim 1, wherein the ARM controller is an LPC11C24 control chip of ARM Cortex-M0, the ARM controller is integrated with a TJF1051 CAN transceiver, the motor driving module adopts a BD63860 driving chip, the chip memory module is an internal memory of the ARM controller, and the stepping motor has a 57BYG250 series two-phase four-hybrid beat mode.

3. The computerized flat knitting machine fabric density adjusting upper computer system according to claim 1, wherein the density adjusting module has a specific structure that: the computer flat knitting machine comprises a gear set consisting of a gear Z1, a gear Z2 and a gear Z3, wherein a stepping motor drives the gear set to rotate, a coaxial cam is driven by the rotation of the gear Z3 to move, so that meshes embedded in an inner groove of the cam are linearly displaced, and meanwhile, a mesh triangle connected with the other end of the meshes is driven to slide in a mesh chute; the variable quantity of the fabric density is realized by detecting the pull-down displacement of the yarns through the Hall sensor, the output of the sensor is fed back to the controller through a series of conversions, and the controller outputs control pulses to realize the accurate control of the stepping motor.

4. The upper computer system for adjusting the fabric density of the computerized flat knitting machine according to claim 3, wherein the four Hall sensors are distributed on four quadrant points around the camshaft sleeve at intervals of 90 degrees, and the four distributed quadrant points are circles with the radius of 1.1 mm.

5. An adjusting method of a computerized flat knitting machine fabric density adjusting upper computer system is characterized by comprising the following steps:

step 1, an upper computer enables a CAN transceiver to send control data to an ARM controller in an interrupted mode through a CAN bus, wherein the control data comprises a motor rotation direction, a motor rotation speed, motor zeroing operation data, a current position and an absolute position of a mesh;

step 2, after the ARM controller successfully receives the data, analyzing and processing the control data, and then transmitting the control data to the motor driving module to enable the stitch motor to act according to the appointed direction, speed and position, and the rotation of the motor drives the density adjusting module to move;

step 3, the motor drives the cam coaxially connected with the gear Z3 to do rotary motion through the mechanical transmission of the gear set, and simultaneously, the stitch embedded in the inner groove of the cam does linear displacement and simultaneously drives the stitch triangle connected with the other end of the stitch to uniformly slide in the chute of the bottom plate of the handpiece;

step 4, after the stitch position is adjusted in place, the head of the computerized flat knitting machine moves along the running direction, when the head moves to the position of the selected knitting needle to be knitted, the drop-down displacement of the knitting needle is changed due to the change of the stitch position, so that the depth of the yarn hooked and pulled by the knitting needle, namely the yarn bending depth is changed, and the change of the fabric density is realized;

and 5, changing the yarn bending depth, acquiring the yarn bending depth through detection and acquisition of a Hall sensor, feeding back the acquired data to an ARM controller through position conversion and analog-to-digital conversion, generating an adjusting variable by the ARM controller, and continuously adjusting the degree of the stepping motor according to the variable until the stepping motor is adjusted in place.

6. The adjusting method of the upper computer system for adjusting the fabric density of the computerized flat knitting machine according to claim 5, wherein the upper computer in the step 1 enables the CAN transceiver to send control data to the ARM controller in an interrupted manner through the CAN bus, and the method comprises the following specific steps:

the upper computer sends data to the ARM controller in an interrupt mode, when detecting that an interrupt bit has a corresponding level, the upper computer enters a CAN interrupt receiving link, the ARM receives CAN bus messages and sends CAN messages to generate interrupts, firstly, whether the messages are error messages or not is judged, if the messages are error messages, the messages are directly deleted and returned to wait for the interrupts, if the messages are useful messages, message object numbers are read, the messages are read to an interface register, first buffer Busy bits of the messages are judged, if the messages are 0, the messages are directly stored in the first buffer, if the messages are 1, the Busy bits of the second buffer are judged, if the messages are 0, the second buffer exists, if the messages are 1, the messages are ignored, the messages are returned to wait for the interrupts and are sent again.

7. The adjusting method of the upper computer system for adjusting the fabric density of the computerized flat knitting machine according to claim 5, wherein the feedback control algorithm in the step 5 is specifically as follows:

the method is characterized in that the yarn bending depth is measured and returned by a Hall sensor and is used for analyzing and comparing with a given value, the control deviation is calculated, the closed-loop control of the system is realized, a fuzzy logic rule is added on the basis of the original classical PID closed-loop control algorithm to form a fuzzy PID control algorithm, the control performance of a fabric density adjusting mechanism is improved, and more accurate control is realized.

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