A wall painting machine printing distance control system and method

Abstract

The present invention provides a control system and method for the printing distance of a wall painting machine, the system includes a control unit, a main control unit, a distance sensor, a storage unit and a motor drive unit, the control unit is used to send an interrupt signal after the painting machine completes printing of each line of data, the main control unit is used to trigger the distance sensor to measure the distance to obtain the measured distance, the storage unit is used to store the measured distance between the point to be printed and the distance sensor, the main control unit is also used to obtain the cumulative moving distance from the nozzle to the point to be printed, calculate the current printing distance of the nozzle according to the measured distance and the cumulative moving distance, judge whether the current printing distance is equal to the preset printing distance threshold, if not, adjust the distance between the nozzle and the point to be printed until the current printing distance is equal to the preset printing distance threshold. The present invention can adjust the printing distance in real time, improve the wall printing quality, and avoid the nozzle from being damaged due to collision with the wall.

Description

Technical Field

[0001] The present invention relates to the technical field of wall painting machines, and in particular to a control system and method for a printing distance of a wall painting machine. Background Art

[0002] In the process of wall painting, the control of printing distance is crucial to the printing effect. If the printing distance is too far or too close, the flying state of ink droplets will change, resulting in poor printing effect and the appearance of satellite ink dots. In addition, different types of nozzles have different optimal printing distances. If the printing distance is too small, the nozzle is easy to hit the wall and cause damage to the nozzle. If the printing distance is too large, flying ink will occur, making the printed image blurred.

[0003] The existing method for controlling the printing distance of inkjet printing generally measures the distance at a certain distance in front of the nozzle's travel direction, and then moves the nozzle through a certain algorithm to achieve the purpose of controlling the printing distance.

[0004] However, the existing control method of the printing distance of inkjet printing cannot adjust the printing distance in real time, that is, the printing distance cannot be adjusted when the nozzle is printing a line of pixel data, which easily leads to blurred printing and needs to be improved. Summary of the invention

[0005] Based on this, in order to solve the problem that the existing inkjet printing control method for the printing distance cannot adjust the printing distance in real time and easily leads to blurred printing, the present invention provides a wall painting machine printing distance control system and method, and its specific technical solution is as follows:

[0006] A wall painting machine printing distance control system, comprising a control unit, a main control unit, a distance sensor, a storage unit and a motor drive unit, characterized in that the control unit is used to send an interrupt signal after the painting machine completes printing a line of data, the main control unit is connected with the control unit and the distance sensor signal, and is used to trigger the distance sensor to measure the distance to obtain the measured distance, and the storage unit is used to store the measured distance between the point to be printed and the distance sensor;

[0007] The main control unit is also used to obtain the cumulative moving distance of the nozzle to the point to be printed, calculate the current printing distance of the nozzle according to the measured distance and the cumulative moving distance, and judge whether the current printing distance is equal to the preset printing distance threshold. If the current printing distance is not equal to the preset printing distance threshold, the motor drive module is triggered and the distance sensor is continuously triggered to calculate the current printing distance of the nozzle and feed back to the motor drive unit, and the distance between the nozzle and the point to be printed is adjusted until the current printing distance is equal to the preset printing distance threshold.

[0008] The printing distance control system of the wall painting machine measures the distance of the wall position to be printed by judging the interrupt signal when each column of pixels is printed, and stores the distance in the storage unit. Before the nozzle reaches the position for printing, the measured distance is taken out from the storage unit, and the actual distance of the current nozzle to the wall (i.e., the current printing distance) is calculated in combination with the cumulative moving distance of the nozzle. The distance between the nozzle and the point to be printed is adjusted. The change of the distance to the wall measured by the distance sensor can be combined. When the nozzle is printing a line of pixel data, the printing distance is adjusted in real time, thereby solving the problem that the existing inkjet printing control method for the printing distance cannot adjust the printing distance in real time and easily leads to blurred printing. The quality of wall printing is improved, and the nozzle can be prevented from being damaged due to collision with the wall.

[0009] Furthermore, the main control unit is also used to store the measured distance into the storage unit when the printing distance is equal to a preset printing distance threshold.

[0010] Furthermore, the control unit is a FPGA unit.

[0011] A method for controlling the printing distance of a wall painting machine is applied to the method for controlling the printing distance of a wall painting machine, and comprises the following steps:

[0012] After the color printer finishes printing a line of data, it sends an interrupt signal;

[0013] In response to each interrupt signal, obtain and store the measured distance between the point to be printed and the distance sensor;

[0014] Obtain the cumulative moving distance of the nozzle to the point to be printed, and calculate the current printing distance of the nozzle based on the measured distance and the cumulative moving distance;

[0015] Determine whether the current printing distance is equal to the preset printing distance threshold. If the current printing distance is not equal to the preset printing distance threshold, adjust the distance between the nozzle and the point to be printed until the current printing distance is equal to the preset printing distance threshold.

[0016] Furthermore, the specific method of obtaining the cumulative moving distance of the nozzle to the point to be printed and calculating the current printing distance of the nozzle according to the measured distance and the cumulative moving distance includes the following steps:

[0017] Set the printing distance threshold, the initial cumulative moving distance S=0, and the initial measurement distance of the storage unit is pre-stored as the printing distance threshold;

[0018] Wait for the print head to finish printing the previous line of pixel data, and send an interrupt signal when the print head finishes printing the previous line of pixel data;

[0019] Taking out the measured distance H stored in the storage unit;

[0020] Obtain the cumulative moving distance S of the nozzle to the point to be printed;

[0021] The current printing distance of the nozzle is calculated based on the measured distance and the accumulated moving distance = measured distance H + accumulated moving distance S.

[0022] Further, the specific method of judging whether the current printing distance is equal to the preset printing distance threshold, and if the current printing distance is not equal to the preset printing distance threshold, adjusting the distance between the nozzle and the point to be printed until the printing distance is equal to the preset printing distance threshold, comprises the following steps:

[0023] Trigger the distance sensor to obtain the current measured distance H1 between the distance sensor and the wall;

[0024] Determine whether the calculated current printing distance of the printhead is equal to a preset printing distance threshold;

[0025] When the calculated current printing distance is not equal to the preset printing distance threshold, the distance sensor is triggered to obtain the measured distance H2 between the current distance sensor and the wall;

[0026] Calculate the distance change between the current position of the distance sensor and the last distance measurement to obtain the current printing distance of the printhead;

[0027] According to the distance change value and the current printing distance of the nozzle, the nozzle is driven to move until the current printing distance of the nozzle is equal to the preset printing distance threshold.

[0028] Further, the method of judging whether the current printing distance is equal to the preset printing distance threshold, and if the current printing distance is not equal to the preset printing distance threshold, adjusting the distance between the nozzle and the point to be printed until the printing distance is equal to the preset printing distance threshold, further comprises the following steps:

[0029] If the calculated current printing distance is equal to the printing distance threshold, the distance sensor is triggered to obtain the measured distance H between the current distance sensor and the wall, and the measured distance H is stored in the storage unit;

[0030] According to the measured distance H1 and the measured distance H, the cumulative moving distance S of the nozzle is calculated as S=S+(measured distance H-measured distance H1);

[0031] After the print head finishes printing the current row of pixel data, an interrupt signal is issued.

[0032] Furthermore, a computer-readable storage medium stores a computer program, which implements the wall painting machine printing distance control method when the computer program is executed by a processor. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The present invention can be further understood from the following description in conjunction with the accompanying drawings. The components in the figures are not necessarily drawn to scale, but the emphasis is placed on illustrating the principles of the embodiments. In different views, the same reference numerals designate corresponding parts.

[0034] Figure 1 It is a schematic diagram of the overall structure of a printing distance control system of a wall painting machine in one embodiment of the present invention;

[0035] Figure 2 It is a schematic diagram of the positional relationship between a distance sensor and a nozzle of a wall painting machine printing distance control system in one embodiment of the present invention;

[0036] Figure 3 It is a schematic diagram of the overall process of a method for controlling the printing distance of a wall painting machine in one embodiment of the present invention;

[0037] Figure 4 It is a schematic diagram of the overall process of a method for controlling the printing distance of a wall painting machine in another embodiment of the present invention.

[0038] Description of reference numerals:

[0039] 1. Distance sensor; 2. Nozzle. DETAILED DESCRIPTION

[0040] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with its embodiments. It should be understood that the specific implementation methods described herein are only used to explain the present invention and do not limit the protection scope of the present invention.

[0041] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0043] The “first” and “second” mentioned in the present invention do not represent specific quantities and orders, but are merely used to distinguish names.

[0044] like Figure 1 As shown, a wall painting machine printing distance control system in one embodiment of the present invention includes a control unit, a main control unit, a distance sensor, a storage unit and a motor drive unit, wherein the control unit is used to send an interrupt signal after the painting machine completes printing a line of data, the main control unit is connected to the control unit and the distance sensor signal, and is used to trigger the distance sensor to measure the distance to obtain the measured distance, and the storage unit is used to store the measured distance between the point to be printed and the distance sensor.

[0045] The main control unit is also used to obtain the cumulative moving distance of the nozzle to the point to be printed, calculate the current printing distance of the nozzle according to the measured distance and the cumulative moving distance, and judge whether the current printing distance is equal to the preset printing distance threshold. If the current printing distance is not equal to the preset printing distance threshold, the motor drive module is triggered and the distance sensor is continuously triggered to calculate the current printing distance of the nozzle and feed back to the motor drive unit, and the distance between the nozzle and the point to be printed is adjusted until the current printing distance is equal to the preset printing distance threshold.

[0046] Specifically, if Figure 2 As shown, the distance sensor 1 and the nozzle 2 are separated by a certain distance and connected and fixed together. The distance sensor 1 is in front of the moving direction of the nozzle 2. The control unit is an FPGA unit. The nozzle is installed on a motor, and the motor is used to respond to the control command issued by the motor drive unit to drive the nozzle to move to adjust the distance between the nozzle and the point to be printed.

[0047] The motor can adjust the distance sensor and the distance of the nozzle relative to the wall at the same time.

[0048] The main control unit compares the current printing distance with the preset printing distance threshold. If the current printing distance and the preset printing distance threshold are not equal, the motor control module is triggered and the distance sensor is continuously triggered to calculate the current printing distance of the nozzle and feed back to the motor drive unit, so that the motor drive unit can use the PID algorithm to drive the motor quickly and stably, and then adjust the distance between the nozzle and the point to be printed until the current printing distance is equal to the preset printing distance threshold. When the current printing distance is equal to the preset printing distance threshold, the measured distance is stored in the storage unit, and when the nozzle moves to the position of the distance sensor, it communicates with the storage unit and takes it out from the storage unit.

[0049] The printing distance control system of the wall painting machine measures the distance of the wall position to be printed by judging the interrupt signal when each column of pixels is printed, and stores the distance in the storage unit. Before the nozzle reaches the position for printing, the measured distance is taken out from the storage unit, and the actual distance of the current nozzle to the wall (i.e., the current printing distance) is calculated in combination with the cumulative moving distance of the nozzle. The distance between the nozzle and the point to be printed is adjusted. The change of the distance to the wall measured by the distance sensor can be combined. When the nozzle is printing a line of pixel data, the printing distance is adjusted in real time, thereby solving the problem that the existing inkjet printing control method for the printing distance cannot adjust the printing distance in real time and easily leads to blurred printing. The quality of wall printing is improved, and the nozzle can be prevented from being damaged due to collision with the wall.

[0050] In addition, the present invention uses a fast interruption method to trigger the main control unit, which can avoid missing the signal of the completion of printing of the previous line of pixel data and adjust the printing distance in time.

[0051] After the distance sensor measures the distance to the point to be printed, until the nozzle moves to the point to be printed, the measured distance measured by the distance sensor during this period is stored in the storage unit, and the measured distance of the storage unit is updated after the nozzle finishes spraying each line of pixel data. This storage method allows the maximum fixed distance between the distance sensor and the nozzle to depend on the capacity of the memory, which is convenient for adjusting the fixed distance between the nozzle and the distance sensor, and also easy to increase the number of printing nozzles.

[0052] In one embodiment, if Figure 3 As shown, a method for controlling the printing distance of a wall painting machine is applied to the above-mentioned method for controlling the printing distance of a wall painting machine, and comprises the following steps:

[0053] S1, after the printer finishes printing a line of data, it sends an interrupt signal.

[0054] S2, responding to each interrupt signal, obtaining and storing the measured distance between the point to be printed and the distance sensor.

[0055] That is, in the direction of the nozzle movement, the distance sensor acquires the measured distance at every pixel distance, and stores the measured distance in the storage unit.

[0056] S3, obtaining the cumulative moving distance of the nozzle to the point to be printed, and calculating the current printing distance of the nozzle according to the measured distance and the cumulative moving distance.

[0057] Wait for the print head to reach the position of the point to be printed and the previous line of data is printed. After the interrupt signal arrives, calculate the current printing distance based on the accumulated print head offset distance when the print head reaches this position.

[0058] S4, determining whether the current printing distance is equal to a preset printing distance threshold; if the current printing distance is not equal to the preset printing distance threshold, adjusting the distance between the nozzle and the point to be printed until the current printing distance is equal to the preset printing distance threshold.

[0059] like Figure 4 As shown, if the current printing distance is not equal to the preset printing distance threshold, the driving motor adjusts the distance between the nozzle and the distance sensor to the wall. At the same time, the relative displacement between the nozzle and the wall is measured by the distance sensor and fed back to the motor driving unit. The PID control algorithm is used to quickly and accurately make the current printing distance equal to the preset printing distance threshold.

[0060] Specifically, if Figure 3 as well as Figure 4 As shown, in step S3, the cumulative moving distance of the nozzle to the point to be printed is obtained, and the specific method of calculating the current printing distance of the nozzle according to the measured distance and the cumulative moving distance includes the following steps:

[0061] S30, setting a printing distance threshold, the initial cumulative moving distance S=0, and the initialization measurement distance of the storage unit is pre-stored as the printing distance threshold.

[0062] S31, waiting for the print head to finish printing the previous line of pixel data, and sending an interrupt signal when the print head finishes printing the previous line of pixel data.

[0063] S32, taking out the measured distance H stored in the storage unit.

[0064] S33, obtaining the cumulative moving distance S of the nozzle to the point to be printed.

[0065] S34, calculating the current printing distance of the nozzle according to the measured distance and the accumulated moving distance = measured distance H + accumulated moving distance S.

[0066] Here, the cumulative moving distance refers to the change in the moving distance between the original position of the nozzle and the position after the nozzle moves.

[0067] like Figure 3 as well as Figure 4 As shown, in step S4, it is determined whether the current printing distance is equal to the preset printing distance threshold. If the current printing distance is not equal to the preset printing distance threshold, the distance between the nozzle and the point to be printed is adjusted until the printing distance is equal to the preset printing distance threshold. The specific method includes the following steps:

[0068] S40, triggering the distance sensor to obtain the current measured distance H1 between the distance sensor and the wall.

[0069] S41, determining whether the calculated current printing distance of the nozzle is equal to a preset printing distance threshold.

[0070] S42, when the calculated current printing distance is not equal to the preset printing distance threshold, the distance sensor is triggered to obtain the measured distance H2 between the current distance sensor and the wall.

[0071] S43, calculating the distance change value between the distance sensor at the current position and the last distance measurement, obtaining the current printing distance of the nozzle and feeding it back to the motor drive unit.

[0072] S44, driving the nozzle to move according to the distance change value and the current printing distance of the nozzle until the current printing distance of the nozzle is equal to a preset printing distance threshold.

[0073] That is to say, according to the feedback from the distance sensor, the main control unit uses the PID control algorithm to drive the motor quickly and stably to adjust the printing distance of the nozzle until the current printing distance of the nozzle is equal to the preset printing distance threshold.

[0074] In one embodiment, if Figure 3 as well as Figure 4 As shown, in step S4, it is determined whether the current printing distance is equal to the preset printing distance threshold. If the current printing distance is not equal to the preset printing distance threshold, the distance between the nozzle and the point to be printed is adjusted until the printing distance is equal to the preset printing distance threshold. The specific method also includes the following steps:

[0075] If the calculated current printing distance is equal to the printing distance threshold, the distance sensor is triggered to obtain the measured distance H between the current distance sensor and the wall, and the measured distance H is stored in the storage unit to be used when the inkjet tray moves to the position of the distance sensor;

[0076] The final moving distance when the nozzle moves to the position of the distance sensor is added to the cumulative moving distance of the nozzle, and the cumulative moving distance S of the nozzle is calculated according to the measured distance H1 and the measured distance H=S+(measured distance H-measured distance H1);

[0077] After the print head finishes printing the current row of pixel data, an interrupt signal is issued.

[0078] The printing distance control method of the wall painting machine measures the distance of the wall position to be printed by judging the interrupt signal when each column of pixels is printed, and stores the distance in a storage unit. Before the nozzle reaches the position for printing, the measured distance is taken out from the storage unit, and the actual distance of the current nozzle to the wall (i.e., the current printing distance) is calculated in combination with the cumulative moving distance of the nozzle. The distance between the nozzle and the point to be printed is adjusted, and the change of the distance to the wall measured by the distance sensor can be combined. When the nozzle is printing a line of pixel data, the printing distance is adjusted in real time, thereby solving the problem that the existing inkjet printing control method for the printing distance cannot adjust the printing distance in real time and easily leads to blurred printing, thereby improving the wall printing quality and preventing the nozzle from being damaged due to collision with the wall.

[0079] In addition, in the present invention, the motor and the distance sensor are fixed as one, and during the process of the motor adjusting the printing distance, the motor can be controlled using the PID algorithm through the real-time distance changes fed back by the distance sensor, thereby increasing the speed and stability of the motor drive, thereby quickly and accurately adjusting the printing distance in real time, so that the current printing distance is equal to the preset printing distance threshold.

[0080] In one embodiment, the present invention provides a computer-readable storage medium storing a computer program, which implements the method for controlling the printing distance of a wall painting machine when the computer program is executed by a processor.

[0081] In summary, the wall painting machine printing distance control system and method described in the present invention can at least achieve the following technical effects:

[0082] 1. By judging the interrupt signal when each column of pixels is printed, the distance to the wall position to be printed is measured and stored in the storage unit. Before the nozzle reaches the position for printing, the measured distance is taken out from the storage unit, and the actual distance of the current nozzle to the wall (i.e. the current printing distance) is calculated in combination with the cumulative moving distance of the nozzle. The distance between the nozzle and the point to be printed can be adjusted. The change of the distance to the wall measured by the distance sensor can be combined. When the nozzle is printing a line of pixel data, the printing distance is adjusted in real time, which solves the problem of the existing inkjet printing control method for the printing distance, which cannot adjust the printing distance in real time and easily leads to blurred printing. The quality of wall printing is improved, and the nozzle can be prevented from being damaged by colliding with the wall.

[0083] 2. The main control unit is triggered by fast interruption, which can avoid missing the signal of the completion of printing of the previous line of pixel data and adjust the printing distance in time.

[0084] 3. The motor and the distance sensor are fixed as one. When the motor adjusts the printing distance, the motor can be controlled by the PID algorithm through the real-time distance change fed back by the distance sensor, so as to increase the speed and stability of the motor drive, thereby quickly and accurately adjusting the printing distance in real time, so that the current printing distance is equal to the preset printing distance threshold.

[0085] 4. After the distance sensor measures the distance to the point to be printed, until the nozzle moves to the point to be printed, the measured distance measured by the distance sensor during this period is stored in the storage unit, and the measured distance of the storage unit is updated after the nozzle finishes spraying a line of pixel data. This storage method allows the maximum fixed distance between the distance sensor and the nozzle to depend on the capacity of the memory, which is convenient for adjusting the fixed distance between the nozzle and the distance sensor, and also easy to increase the number of printing nozzles.

[0086] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0087] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A wall painting machine printing distance control system, comprising a control unit, a main control unit, a distance sensor, a storage unit and a motor drive unit, characterized in that: The control unit is used to send out an interrupt signal after the color plotter completes printing of each line of data. The main control unit is connected with the control unit and the distance sensor signal to trigger the distance sensor to measure the distance to obtain the measured distance. The storage unit is used to store the measured distance between the point to be printed and the distance sensor. The main control unit is also used to obtain the cumulative moving distance of the nozzle to the point to be printed, calculate the current printing distance of the nozzle according to the measured distance and the cumulative moving distance, and judge whether the current printing distance is equal to the preset printing distance threshold. If the current printing distance is not equal to the preset printing distance threshold, the motor drive module is triggered and the distance sensor is continuously triggered to calculate the current printing distance of the nozzle and feed back to the motor drive unit, and the distance between the nozzle and the point to be printed is adjusted until the current printing distance is equal to the preset printing distance threshold. The specific method of obtaining the cumulative moving distance of the nozzle to the point to be printed and calculating the current printing distance of the nozzle according to the measured distance and the cumulative moving distance includes the following steps: Set the printing distance threshold, the initial cumulative moving distance S=0, and the initial measurement distance of the storage unit is pre-stored as the printing distance threshold; Wait for the print head to finish printing the previous line of pixel data, and send an interrupt signal when the print head finishes printing the previous line of pixel data; Taking out the measured distance H stored in the storage unit; Obtain the cumulative moving distance S of the nozzle to the point to be printed; The current printing distance of the nozzle is calculated based on the measured distance and the accumulated moving distance = measured distance H + accumulated moving distance S.

2. A wall painting machine printing distance control system as claimed in claim 1, characterized in that: The main control unit is also used to store the measured distance in the storage unit when the printing distance is equal to a preset printing distance threshold.

3. A wall painting machine printing distance control system as claimed in claim 2, characterized in that: The control unit is a FPGA unit.

4. A method for controlling the printing distance of a wall painting machine, applied to the method for controlling the printing distance of a wall painting machine as claimed in any one of claims 1 to 3, characterized in that: The wall painting machine printing distance control method comprises the following steps: After the color printer finishes printing a line of data, it sends an interrupt signal; In response to each interrupt signal, obtain and store the measured distance between the point to be printed and the distance sensor; Obtain the cumulative moving distance of the nozzle to the point to be printed, and calculate the current printing distance of the nozzle based on the measured distance and the cumulative moving distance; Determine whether the current printing distance is equal to a preset printing distance threshold. If the current printing distance is not equal to the preset printing distance threshold, adjust the distance between the nozzle and the point to be printed until the current printing distance is equal to the preset printing distance threshold. The specific method of obtaining the cumulative moving distance of the nozzle to the point to be printed and calculating the current printing distance of the nozzle according to the measured distance and the cumulative moving distance includes the following steps: Set the printing distance threshold, the initial cumulative moving distance S=0, and the initial measurement distance of the storage unit is pre-stored as the printing distance threshold; Wait for the print head to finish printing the previous line of pixel data, and send an interrupt signal when the print head finishes printing the previous line of pixel data; Taking out the measured distance H stored in the storage unit; Obtain the cumulative moving distance S of the nozzle to the point to be printed; The current printing distance of the nozzle is calculated based on the measured distance and the accumulated moving distance = measured distance H + accumulated moving distance S.

5. A method for controlling the printing distance of a wall painting machine as claimed in claim 4, characterized in that: The specific method of judging whether the current printing distance is equal to the preset printing distance threshold, and if the current printing distance is not equal to the preset printing distance threshold, adjusting the distance between the nozzle and the point to be printed until the printing distance is equal to the preset printing distance threshold, comprises the following steps: Trigger the distance sensor to obtain the current measured distance H1 between the distance sensor and the wall; Determine whether the calculated current printing distance of the printhead is equal to a preset printing distance threshold; When the calculated current printing distance is not equal to the preset printing distance threshold, the distance sensor is triggered to obtain the measured distance H2 between the current distance sensor and the wall; Calculate the distance change between the current position of the distance sensor and the last distance measurement to obtain the current printing distance of the printhead; According to the distance change value and the current printing distance of the nozzle, the nozzle is driven to move until the current printing distance of the nozzle is equal to the preset printing distance threshold.

6. A method for controlling the printing distance of a wall painting machine as claimed in claim 5, characterized in that: The specific method of judging whether the current printing distance is equal to a preset printing distance threshold, and if the current printing distance is not equal to the preset printing distance threshold, adjusting the distance between the nozzle and the point to be printed until the printing distance is equal to the preset printing distance threshold, further comprises the following steps: If the calculated current printing distance is equal to the printing distance threshold, the distance sensor is triggered to obtain the measured distance H between the current distance sensor and the wall, and the measured distance H is stored in the storage unit; According to the measured distance H1 and the measured distance H, the cumulative moving distance S of the nozzle is calculated as S=S+(measured distance H-measured distance H1); After the print head finishes printing the current row of pixel data, an interrupt signal is issued.

7. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed by the processor, the method for controlling the printing distance of a wall painting machine as described in any one of claims 4 to 6 is implemented.

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