Accurate positioning control system for heavy-load RGV
Through the staged operation method of combining the servo motor with its own encoder and laser sensor, the problem of insufficient positioning accuracy and high cost of heavy-load RGV is solved, efficient and accurate positioning control is achieved, and maintenance costs are reduced.
Patent Information
- Application Number
- CN202411416853.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-11
- Publication Date
- 2025-01-03
AI Technical Summary
The existing heavy-load RGV positioning methods have problems with insufficient accuracy and high cost. There are measurement errors in laser rangefinders or coding scales. The servo motor's own encoder ignores track slippage when running at low speed, resulting in positioning errors and high maintenance costs.
Using the servo motor's own encoder as a position reference, combined with laser sensor and positioning mark, it runs in stages. The first stage position mode runs at the maximum speed, and the second stage speed mode runs at low speed. The laser sensor stops the servo when detecting positioning marks. Motor reduces the impact of track slippage, improves positioning accuracy and operating efficiency.
Improve positioning accuracy, reduce project and maintenance costs, and ensure efficient operation of heavy-load RGV and accurate reaching of target points.
Smart Images
Figure CN119247851A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of heavy-load rail-guided vehicles, and in particular relates to a heavy-load RGV precise positioning control system. Background Art
[0002] RGV (Rail Guided Vehicle, RGV for short), a rail-guided vehicle, refers to a small vehicle that runs on a specific track. It does not require human operation, runs automatically, and has a high running speed.
[0003] In the past, heavy-load RGV positioning methods usually adopted two methods.
[0004] First, a laser rangefinder or code ruler is used as the positioning reference, and the machine runs in sections. When the machine is about to reach the target point, the machine slows down in advance and runs at a low speed until it stops at the target point. This design assumes that the laser rangefinder or code ruler is the absolute position. However, in fact, both the laser rangefinder and the code ruler have measurement errors and error risks, which will lead to insufficient accuracy or even positioning errors, and the project cost and maintenance cost are high. Second, the servo motor's built-in encoder is used as a positioning reference. The operation is also divided into two stages. In the first stage, the speed mode is switched to the position mode and the vehicle runs at a low speed until it stops at the target point after reaching a certain distance from the target point. This method still has the risk of track slippage when running in the second stage position mode, but the solution design defaults to ignoring track slippage when running at low speed, and there is still insufficient positioning accuracy or even positioning errors. This solution has a lower cost, but the positioning accuracy error is larger and there is a risk of positioning errors.
[0005] Therefore, it is necessary to design a heavy-duty RGV precise positioning control system that can improve positioning accuracy and ensure operating efficiency to solve the current technical problems. Summary of the invention
[0006] In view of the deficiencies in the prior art, the present invention provides a heavy-duty RGV precise positioning control system that improves positioning accuracy and ensures operating efficiency.
[0007] The technical solution of the present invention is: a heavy-load RGV precise positioning control system, comprising: a control device arranged on a vehicle body and a positioning marker arranged at each workstation; the control device comprises a main controller, a communication module, a servo driver, a servo motor and a laser sensor, the main controller is connected to the servo driver through the communication module, the main controller sends a motion control instruction to the servo driver through the communication module, and the servo driver reports positioning information to the main controller through the communication module; the servo motor is used to drive the driving wheel to rotate to drive the vehicle body to move on the track; the laser sensor is connected to the main controller, the laser sensor is used to detect the positioning marker, and when the laser sensor detects the positioning marker, it sends a signal to the main controller, and the main controller stops the operation of the servo motor.
[0008] The control method of the main controller includes: dividing the total mileage between the current workstation and the target workstation into a first-stage position mode mileage and a second-stage speed mode mileage; in the first-stage position mode mileage, the main controller controls the servo motor to drive the vehicle body to run along the track at a system-designed maximum speed, and in the second-stage speed mode mileage, the main controller controls the servo motor to drive the vehicle body to run along the track at a speed lower than the system-designed maximum speed; in the second-stage speed mode mileage, when the laser sensor detects a positioning marker, a signal is sent to the main controller, and the main controller stops the operation of the servo motor.
[0009] The second-stage speed mode mileage is a fixed value, and the first-stage position mode mileage is obtained by subtracting the total mileage from the second-stage speed mode mileage.
[0010] The first stage position mode mileage is 0~50mm.
[0011] The first stage position mode mileage is 20mm.
[0012] In the second stage speed mode mileage, the main controller controls the servo motor to drive the vehicle body to run along the track at 0.1-2.0 m / min.
[0013] In the second stage speed mode mileage, the main controller controls the servo motor to drive the vehicle body to run along the track at 0.8 m / min.
[0014] The laser sensor is a single-point laser sensor, and the spot diameter of the single-point laser sensor is 1.5 mm.
[0015] The width of the positioning marker is 3 mm.
[0016] The communication module is a CANopen communication module.
[0017] Beneficial effects of the present invention: (1) In the present invention, the encoder of the servo motor is used as a rough position reference, and the positioning marker installed at the target station is used as an absolute position standard. The positioning marker is fixedly installed at the target station to avoid positioning standard errors; (2) The distance between the current workstation and the target workstation is divided into two stages. The adverse effects of track slippage are placed in the first stage. The servo motor operates in position mode, allowing track slippage to cause errors in the first stage distance. In the second stage, the servo motor operates in speed mode at a low speed. The laser sensor stops when it senses the positioning marker of the target workstation. The first stage runs at full speed, and the second stage runs a very short distance. Low-speed operation will not affect the overall efficiency. At the same time, it improves positioning accuracy and reduces project and maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 It is a principle block diagram of the control device in the heavy-load RGV precise positioning control system of the present invention.
[0019] Figure 2 This is a positioning principle diagram of the heavy-duty RGV precision positioning control system in the present invention. DETAILED DESCRIPTION
[0020] Various exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The description of the exemplary embodiments is merely illustrative and is not intended to be any limitation on the present invention and its application or use. The present invention can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are provided to make the present invention thorough and complete and to fully express the scope of the present invention to those skilled in the art. It should be noted that unless otherwise specifically stated, the relative arrangement of the parts and steps, the composition of the materials, the numerical expressions and the numerical values set forth in these embodiments should be interpreted as being merely exemplary and not as limitations.
[0021] The words "first", "second" and similar words used in the present invention do not indicate any order, quantity or importance, but are only used to distinguish different parts. The words "include" or "comprise" and similar words mean that the elements before the word include the elements listed after the word, and do not exclude the possibility of including other elements. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.
[0022] like Figure 1 and 2As shown, the heavy-duty RGV precise positioning control system includes: a control device arranged on the vehicle body and a positioning marker 6 arranged at each workstation; the control device includes a main controller 1, a communication module 2, a servo driver 3, a servo motor 4 and a laser sensor 5. The main controller 1 is connected to the servo driver 3 through the communication module 2, and the main controller 1 sends a motion control instruction to the servo driver 3 through the communication module 2, and the servo driver 3 reports the positioning information to the main controller 1 through the communication module 2; the servo motor 4 is used to drive the driving wheel to rotate to drive the vehicle body to move on the track; the laser sensor 5 is connected to the main controller 1, and the laser sensor 5 is used to detect the positioning marker 6. When the laser sensor 5 detects the positioning marker 6, it sends a signal to the main controller 1, and the main controller 1 stops the servo. The servo motor 4 is running; in the present embodiment, the encoder provided by the servo motor is used as a rough position reference, and the positioning marker 6 installed at the target station is used as an absolute position standard. The positioning marker 6 is fixedly installed at the target station to avoid positioning standard errors; the distance between the current station and the target station is divided into two stages for operation. In the first stage, the adverse effect of track slippage is placed in the first stage. The servo motor is operated in position mode, and track slippage is allowed to cause distance errors in the first stage. In the second stage, the servo motor is operated in speed mode at a low speed. The laser sensor stops when it senses the positioning marker 6 at the target station. The first stage runs at full speed, and the second stage runs at an extremely short distance. Running at a low speed will not affect the overall efficiency, while improving positioning accuracy and reducing project and maintenance costs.
[0023] In some embodiments, the control method of the main controller 1 includes: dividing the total mileage between the current workstation and the target workstation into a first-stage position mode mileage and a second-stage position mode mileage; in the first-stage position mode mileage, the main controller 1 controls the servo motor 4 to adopt a position mode to drive the vehicle body to run along the track at a system-designed maximum speed, and in the second-stage position mode mileage, the main controller 1 controls the servo motor 4 to adopt a speed control mode to drive the vehicle body to run along the track at a speed lower than the system-designed maximum speed; in the second-stage position mode mileage, when the laser sensor 5 detects the positioning marker 6, a signal is sent to the main controller 1, and the main controller 1 stops the servo motor 4 from running; in order to ensure the high-efficiency operation and high positioning accuracy of the heavy-load RGV, the operation of the heavy-load RGV The operation is divided into the first stage and the second stage. The total mileage between the current workstation and the target workstation can be divided into the first stage position mode mileage and the second stage speed mode mileage. In the first stage, the main controller 1 controls the servo motor 4 to adopt the position mode to run at the maximum speed of the system design, and its operation efficiency will not be reduced. When the heavy-loaded RGV reaches the end of the first stage position mode mileage calculated in the main controller 1, it enters the second stage. In the second stage, the servo motor adopts the speed mode to run at a lower speed. When the heavy-loaded RGV reaches the target workstation, the laser sensor 5 scans the positioning marker 6 to generate an in-place signal and sends it to the main controller 1. The main controller 1 immediately sends a stop command, the servo motor 4 stops running, and the heavy-loaded RGV stops running to improve the positioning accuracy.
[0024] In some embodiments, the second-stage speed mode mileage is a fixed value, and the difference between the total mileage and the second-stage speed mode mileage is the first-stage position mode mileage; the main controller 1 obtains the distance between the current workstation and the target workstation to obtain the total mileage, and the first-stage position mode mileage is obtained by subtracting the fixed value of the second-stage speed mode mileage from the total mileage. The heavy-loaded RGV immediately enters the second-stage speed mode operation when it reaches the end of the first-stage position mode mileage.
[0025] In the above embodiment, as a specific implementation of the first-stage position mode mileage, the first-stage position mode mileage is 0-50 mm; more specifically, the first-stage position mode mileage is 20 mm.
[0026] In the above embodiment, in order to prevent the heavy-loaded RGV from crossing the positioning marker 6 during high-speed operation in the first stage position mode, the mileage value of the position mode operation is calculated by the positioning program and is slightly smaller than the total mileage value.
[0027] In the above embodiment, in order to prevent the servo motor from having too much inertia when starting and stopping when the RGV runs at high speed in the first stage position mode, the acceleration time and deceleration time are set, and when running in the position mode, the servo driver will automatically calculate the stopping distance to decelerate in advance, and the heavy-loaded RGV is relatively stable when stopping; in the second stage speed mode, the running speed is lower, and no large inertia will be generated when starting and stopping, and no processing is required.
[0028] In some embodiments, in the second stage speed mode mileage, the main controller controls the servo motor to drive the vehicle body to run along the track at 0.1~2.0m / min; specifically, in the second stage speed mode mileage, the main controller controls the servo motor to drive the vehicle body to run along the track at 0.8m / min.
[0029] In some embodiments, in order to accurately position, the second stage servo motor runs in speed mode with a lower speed. When the laser sensor scans the positioning marker 6, it generates an in-position signal and sends it to the main controller. The main controller will immediately send a stop command to the servo driver to stop the operation of the overloaded RGV; the laser sensor 5 is a single-point laser sensor, and the spot diameter of the single-point laser sensor 5 is 1.5mm, the effective action area is half of the spot area, and the light beam does not spread, which does not affect the positioning accuracy. The width of the positioning marker 6 is 3mm.
[0030] In the above embodiment, the communication module 2 is a CANopen communication module, and the main controller 1 is a Siemens 1214 PLC.
[0031] So far, various embodiments of the present invention have been described in detail. In order to avoid obscuring the concept of the present invention, some details known in the art are not described. Based on the above description, those skilled in the art can fully understand how to implement the technical solution disclosed here.
[0032] The above-mentioned embodiments only express some implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.
Claims
1. A heavy-duty RGV precise positioning control system, characterized in that: include: Control devices installed on the vehicle body and positioning markers installed at each workstation; The control device includes a main controller, a communication module, a servo driver, a servo motor and a laser sensor, wherein the main controller is connected to the servo driver through the communication module, the main controller sends a motion control instruction to the servo driver through the communication module, and the servo driver reports positioning information to the main controller through the communication module; The servo motor is used to drive the driving wheel to rotate so as to drive the vehicle body to move on the track; The laser sensor is connected to the main controller and is used to detect a positioning marker. When the laser sensor detects a positioning marker, a signal is sent to the main controller, and the main controller stops the servo motor from running.
2. The heavy-duty RGV precise positioning control system according to claim 1 is characterized in that: The control method of the main controller includes: The total mileage between the current workstation and the target workstation is divided into the first-stage position mode mileage and the second-stage speed mode mileage; In the first stage position mode mileage, the main controller controls the servo motor to drive the vehicle body to run along the track at the maximum speed designed by the system, and in the second stage speed mode mileage, the main controller controls the servo motor to drive the vehicle body to run along the track at a speed lower than the maximum speed designed by the system; In the second stage speed mode mileage, when the laser sensor detects the positioning marker, a signal is sent to the main controller, and the main controller stops the operation of the servo motor.
3. The heavy-duty RGV precise positioning control system according to claim 2 is characterized in that: The second-stage speed mode mileage is a fixed value, and the first-stage position mode mileage is obtained by subtracting the total mileage from the second-stage speed mode mileage.
4. The heavy-duty RGV precise positioning control system according to claim 3 is characterized in that: The first stage position mode mileage is 0~50mm.
5. The heavy-duty RGV precise positioning control system according to claim 4 is characterized in that: The first stage position mode mileage is 20mm.
6. The heavy-duty RGV precise positioning control system according to claim 2 is characterized in that: In the second stage speed mode mileage, the main controller controls the servo motor to drive the vehicle body to run along the track at 0.1-2.0 m / min.
7. The heavy-duty RGV precise positioning control system according to claim 6 is characterized in that: In the second stage speed mode mileage, the main controller controls the servo motor to drive the vehicle body to run along the track at 0.8 m / min.
8. The heavy-duty RGV precise positioning control system according to claim 1 is characterized in that: The laser sensor is a single-point laser sensor, and the spot diameter of the single-point laser sensor is 1.5 mm.
9. The heavy-duty RGV precise positioning control system according to claim 8, characterized in that: The width of the positioning marker is 3 mm.
10. The heavy-duty RGV precise positioning control system according to claim 1, characterized in that: The communication module is a CANopen communication module.