A horizontal axis anchor excavator off-axis control method based on coordinate matching

Abstract

The application discloses a kind of based on coordinate matching's horizontal axis anchor machine off-axis control method, belong to coal mine roadway excavation equipment intelligent control technical field.The method first constructs global coordinate system, determines side position, through anchor machine body axis coordinate, heading angle and pick fixed displacement parameter, real-time solution pick in global coordinate system through coordinate transformation The coordinate of pick, calculate the deviation Δx of pick horizontal coordinate and side coordinate as closed-loop control monitoring quantity according to Δx and drive amount speed difference coefficient K generate left and right track differential drive amount, drive pick approach side;Synchronous monitoring heading angle β, when β exceeds threshold value, pause differential output only keep common speed forward, until β reduce after recovery.The present application takes pick coordinate as direct control target, avoids the overbreak problem caused by pick exceeding side in the process of rectification rotation in traditional centerline cutting method, improves roadway forming precision and excavation safety.

Description

Technical Field

[0001] This invention belongs to the field of intelligent control technology for coal mine roadway excavation equipment, and specifically designs an off-axis control method for a horizontal axis roadway excavator based on coordinate matching. Background Technology

[0002] The horizontal axis roadheader is the core equipment of rapid roadway excavation equipment in coal mines. It integrates cutting and anchoring functions and achieves forward movement and turning through left and right track drive. Because its cutting width is close to the roadway width and the cutting teeth are close to the roadway sidewalls, the trajectory control accuracy during the excavation process directly determines the quality of roadway formation.

[0003] Currently, the mainstream control approach for fast tunneling equipment is the "centerline cutting" method: using the lateral and angular deviations of the tunnel boring machine's centerline from the roadway centerline as detection parameters, the machine is rotated via differential speed driven by the left and right tracks, while simultaneously applying forward drive, gradually bringing the machine's centerline back to the roadway centerline, thus completing trajectory correction. However, this method has significant drawbacks when applied to horizontal-axis tunnel boring machines. A large lateral offset exists between the cutting teeth and the machine's centerline. When lateral deviation exists and rotational correction is performed, the cutting teeth's radius of motion is greater than the radius of motion of the machine's centerline. Even if the machine's centerline successfully returns to the centerline, the cutting teeth may still over-excavate due to the rotation arc exceeding the roadway sidewall. Traditional methods use the machine's centerline deviation as the control basis, but whether the cutting teeth exceed the sidewall is never directly monitored, creating a control blind spot; the larger the heading angle, the more amplified the lateral displacement of the cutting teeth, and the more prominent the risk of over-excavation.

[0004] Therefore, there is an urgent need for a trajectory control method that can directly use the position of the cutting tooth as the control target and match the coordinates of the cutting tooth with the coordinates of the roadway sidewalls to reduce the hidden danger of the cutting tooth going beyond the sidewalls during the rotation correction process and improve its control accuracy. Summary of the Invention

[0005] To address the technical problem in existing roadheader-anchor machines (BAMs) where the cutting teeth may extend beyond the roadway sidewall during trajectory correction using the "centerline cutting" method, causing over-excavation, this invention provides an off-axis control method for BAMs based on coordinate matching. This method establishes a global coordinate system with the roadway sidewall as the X-axis and the excavation direction as the Y-axis. The cutting tooth coordinates are calculated in real-time using coordinate transformation based on the machine's centerline coordinates and yaw angle. The deviation Δx between the cutting tooth's horizontal coordinate and the sidewall coordinates is used as the closed-loop control monitoring quantity. Based on Δx and the differential speed coefficient K, a differential drive quantity is generated between the left and right tracks to bring the cutting tooth closer to the sidewall. Simultaneously, the yaw angle β is limited to prevent excessive machine swing. This process is repeated until Δx and β converge, achieving off-axis trajectory control with the cutting tooth as the anchor point.

[0006] Implementation of the present invention: The off-axis control method for a transverse-axis tunneling and anchoring machine based on coordinate matching of the present invention includes the following steps: Step 1: First, obtain the spatial position of the roadheader at the working face using the navigation and positioning system, and establish a global coordinate system: the X-axis is along the transverse direction of the roadway, the Y-axis is along the longitudinal direction of the roadway (i.e., the direction of roadheading), and the Z-axis points towards the roadway roof. As the roadheader advances, continuously obtain its spatial position relative to the origin of the global coordinate system. Combined with the machine's structural parameters, calculate the real-time coordinates of the cutting teeth, the machine's centerline coordinates, and the roadway sidewall coordinates. After establishing the global coordinate system, obtain the real-time centerline coordinates of the roadheader. And the heading angle β, where β is the angle between the fuselage centerline and the direction of travel in the tunnel.

[0007] Step 2: Real-time calculation of the cutting tooth coordinates. Let 'a' be the longitudinal offset of the cutting tooth in the fuselage's central axis coordinate system, and 'b' be the lateral offset. The coordinates (xc, yc) of the cutting tooth in the global coordinate system are calculated in real-time through coordinate transformation:

[0008] Step 3: Deviation monitoring quantity calculation. Calculate the deviation Δx between the horizontal coordinate xc of the cutting tooth and the coordinate of the roadway sidewall, and use it as the monitoring quantity for closed-loop control. The physical meaning of Δx is the remaining distance between the cutting tooth and the left sidewall of the roadway: the larger Δx is, the farther the cutting tooth is from the sidewall, and the more the differential drive needs to be increased to rotate the machine body towards the sidewall; when Δx approaches zero, it indicates that the cutting tooth is close to the sidewall, and the control target has been achieved.

[0009] Step 4: Differential drive control law, based on the deviation Δx and the preset drive quantity to differential coefficient K, generates the differential drive quantity δ of the left and right tracks, and the heading angle β:

[0010]

[0011] Where K is the differential speed coefficient of the drive quantity to the track rotation, representing the track drive differential speed corresponding to a unit deviation. When Δx is greater than zero, the cutting teeth move away from the sidewall, the differential drive quantity δ is positive, and the fuselage rotates towards the sidewall; when Δx approaches zero, the differential drive quantity δ approaches zero, and the fuselage maintains the current heading. The heading angle β is linearly related to the differential drive quantity, that is, the larger the differential drive quantity, the greater the change in heading angle within a unit control cycle. The left and right tracks are simultaneously applied with a common speed forward drive on the basis of differential drive, so that the blocker maintains forward movement while adjusting its heading.

[0012] Step 5: Heading angle β limiting strategy. During differential drive control, the heading angle β is monitored synchronously. Since β may reach a large value during the correction process, an excessively large heading angle poses a safety risk on site. Therefore, a preset threshold is set for β. When β exceeds the preset threshold, only the common speed forward drive of the left and right tracks is maintained, allowing the machine to naturally return to center due to inertia during forward movement. When β is detected to begin decreasing and fall below the preset threshold, the output of the differential drive is restored, and the control to approach the sidewall continues.

[0013] Step 6: Closed-loop convergence. Steps 2 to 5 are repeated with a preset control cycle. In each control cycle, the cutter coordinates are recalculated, the deviation Δx is calculated, the differential drive quantity is generated, and the β limiting strategy is executed until Δx converges to the target value and β converges to zero, completing the off-axis trajectory control. After convergence, the cutter is in close contact with the left side of the roadway, the machine's heading is consistent with the roadway direction, and the roadheader moves forward at a constant speed along the roadway direction.

[0014] The core idea of ​​this invention is to transform the control monitoring quantity from the traditional "deviation between the machine's centerline and the roadway centerline" to the "deviation Δx between the cutter's coordinates and the roadway sidewall," making the cutter the direct anchor point for closed-loop control. First, a global coordinate system based on the roadway is established. The position of the cutter in the global coordinate system is calculated in real time through coordinate transformation using the machine's centerline coordinates and heading angle. Then, using the deviation Δx between the cutter's horizontal coordinate and the sidewall coordinates as the monitoring quantity, a differential drive quantity for the left and right tracks is generated according to the control law, driving the cutter closer to the sidewall. Simultaneously, a heading angle β threshold limit is set. When β exceeds the limit, the differential output is stopped to prevent excessive machine swing angle, reduce overshoot, and improve the control accuracy of the roadheader. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of sidewall over-excavation using the traditional "centerline cutting" method; Figure 2 This is an overall schematic diagram of the off-axis control method of the present invention; Figure 3 This is a schematic diagram of the establishment of the global coordinate system for the tunnel excavation. Figure 4 This is a flowchart of the closed-loop control method for off-axis control; Figure 5 This is a simulation model diagram of the track control system for the tunneling and anchoring machine; Figure 6 This is a simulation curve of the off-axis closed-loop control effect; Detailed Implementation

[0016] The technical solution of the present invention will be described in detail below with reference to the accompanying drawings and embodiments. 1. Over-excavation problem in traditional methods Figure 1As shown, the traditional "centerline cutting" method uses the deviation between the machine's centerline and the roadway centerline as the control quantity. When the roadheader has a lateral deviation and is rotating to correct it, due to the large lateral offset distance between the cutting teeth of the horizontal axis roadheader and the machine's centerline, the radius of motion of the cutting teeth is greater than the radius of motion of the machine's centerline. During the rotation, the arc of motion of the cutting teeth may exceed the roadway sidewall, causing over-excavation and reducing the quality of roadway formation. Figure 1 Traditional methods rely on the deviation of the fuselage center axis for control, but whether the cutting tooth position exceeds the sidewall is never directly monitored, resulting in a control blind spot.

[0017] 2. The overall concept of the off-axis control method of this invention Figure 2 As shown, an off-axis control method is proposed, transforming the control monitoring quantity from the "deviation between the machine body centerline and the roadway centerline" to the "deviation between the cutting tooth coordinates and the roadway sidewalls," making the cutting tooth the direct anchor point for closed-loop control. For example... Figure 2 As shown, during the tunneling process, the roadheader calculates the coordinates of the cutting tooth in the global coordinate system of the roadway in real time, matches the position of the cutting tooth with the coordinates of the roadway sidewall, drives the cutting tooth to approach the sidewall and eventually sticks to the sidewall, and controls the machine body to be consistent with the roadway direction, so as to realize off-axis trajectory control with the cutting tooth as the anchor point, and avoids over-excavation of the sidewall as much as possible during the rotation correction process.

[0018] 3. Establish the global coordinate system and the kinematic model parameters of the tunneling and anchoring machine, as follows: Figure 3 As shown, the coordinate origin is a preset reference point on the left side of the tunnel. The X-axis runs horizontally along the tunnel (with the left side as the zero point), the Y-axis runs vertically along the tunnel, i.e., the direction of excavation, and the Z-axis points towards the tunnel roof. As the roadheader advances, its spatial position relative to the global coordinate origin is continuously acquired. Combined with the machine's structural parameters, the real-time coordinates of the cutting teeth, the machine's central axis coordinates, and the tunnel sidewall coordinates are calculated. The machine's central axis coordinates are marked as follows: The coordinates of the cutting tooth in the global coordinate system are (xc, yc), the angle between the machine body centerline and the roadway direction is denoted as β, and the fixed displacement of the left cutting tooth in the machine body centerline coordinate system is (-a, b).

[0019] 4. Off-axis closed-loop control process input Figure 4 As shown, kinematic calculations are used to achieve this. All state variables (fuselage centerline coordinates, yaw angle, and cutter tooth coordinates) are obtained through the kinematic model of the roadheader. The process mainly includes the following steps: (a): The difference between the xc of the cutting tooth calculated by the kinematic model at the beginning of the control cycle and the coordinate of the left side of the roadway is taken as the deviation Δx, and the initial side position is a preset value, which is used as the input for this control cycle: (b): In differential drive control mode, a constant value v (reference forward speed) is applied to the left track, and the right track drive amount is adjusted according to... Calculate (where k is the differential ratio coefficient in the control law), thereby forming the differential drive amount k·Δx of the left and right tracks, which is used to deflect the fuselage towards the sidewall while moving forward; (c): Calculation of heading angle change: Under differential drive, the change of heading angle β within a unit control cycle Δt is calculated by Σ(Mk·Δx)·Δt (M is a constant coefficient related to the inertia of the tunneling machine and the geometry of the track). The cumulative change of β causes the fuselage to gradually adjust its heading. (d): Axial coordinates The update method for the cutter coordinates (xc, yc) is as follows:

[0020]

[0021] in The initial coordinates of the fuselage axis. The speed of the roadheader (e): Closed-loop iteration, feeding back the updated cutter coordinate xc to step (a) as the input for the next control cycle, and repeating the above steps in a preset control cycle until Δx converges to the target value and β converges to zero.

[0022] 5. The overall control system simulation model is as follows: Figure 5 As shown, the initial distance between the left cutting tooth and the left side of the roadheader is set to 1000mm, the machine width is 3000mm, the roadheader advances 1000mm, and the initial heading angle is 5°. Simulations yielded the trajectory curves of the left cutting tooth on the roadheader shaft and the changes in the heading angle. Figure 6 As can be seen, through the off-axis control method, the roadheader is gradually controlled from a certain distance from the left side of the roadway to the point where the left cutting tooth is tightly against the left side, and the axial direction of the roadheader body is aligned with the roadway direction. This verifies that the method of the present invention can use the cutting tooth as a closed-loop control anchor point to accurately track the roadway side while simultaneously reducing the heading angle of the machine body.

Claims

1. A method for off-axis control of a transverse-axis tunneling and anchoring machine based on coordinate matching, comprising the following steps: Step S1: Establish a global coordinate system of the tunneling roadway to determine the left side position of the roadway, the tunneling advancing direction is Y axis, and the machine body center axis coordinate of the tunneling anchor machine in the global coordinate system is obtained in real time through the pose measurement device and the heading angle β; Step S2: according to the fuselage axis coordinates , the heading angle β and the fixed displacement parameters of the cutting tooth in the fuselage axis coordinate system, the coordinates (xc, yc) of the cutting tooth in the global coordinate system are solved in real time through coordinate transformation. Step S3: Calculate the deviation Δx between the horizontal coordinate xc of the cutting tooth and the coordinate of the roadway sidewall, and use the deviation Δx as the monitoring quantity for closed-loop control; Step S4: Based on the deviation Δx and the preset drive amount to differential speed coefficient K, generate the differential drive amount of the left and right tracks, so that the cutting tooth approaches the roadway sidewall direction, wherein the heading angle β is linearly related to the differential drive amount; Step S5: Synchronously monitor the heading angle β. When the heading angle β exceeds a preset threshold, pause the output of the differential drive and only retain the common speed forward drive until the heading angle β begins to decrease, then resume the output of the differential drive. S6: Repeat steps S2 to S5 with a preset control cycle until the deviation Δx converges to the target value and the heading angle β converges to zero, thus completing the off-axis trajectory control.

2. The off-axis control method for a transverse-axis tunneling and anchoring machine based on coordinate matching according to claim 1, characterized in that, In step S1, the global coordinate system is established as follows: the corresponding projection point of the laser guidance device installed on the body of the anchor transport machine on the left side of the roadway is taken as the origin of the coordinate system, the X-axis is along the transverse direction of the roadway, the Y-axis is along the longitudinal direction of the roadway, and the Z-axis points towards the roof of the roadway; as the anchor transport machine advances forward, the spatial position of the anchor transport machine relative to the origin of the global coordinate system is continuously obtained, and the real-time coordinates of the cutting teeth, the coordinates of the machine's central axis, and the coordinates of the roadway sidewall are calculated in combination with the machine's structural parameters.

3. The off-axis control method for a transverse-axis tunneling and anchoring machine based on coordinate matching according to claim 1, characterized in that, In step S2, let a be the longitudinal offset of the cutting tooth in the machine body's central axis coordinate system, b be the lateral offset of the cutting tooth in the machine body's central axis coordinate system, and β be the angle between the machine body's central axis and the roadway's forward direction. The coordinates of the cutting tooth in the global coordinate system are calculated using the following formula:

4. The off-axis control method for a transverse-axis tunneling and anchoring machine based on coordinate matching according to claim 1, characterized in that, In step S4, the differential driving amount δ of the left and right tracks and the heading angle β are calculated as follows: Where δ is the differential drive amount of the left and right tracks, K is the differential drive amount to track rotation coefficient, and Δx is the deviation between the abscissa of the cutting tooth and the sidewall coordinate; when Δx is greater than zero, the cutting tooth moves away from the sidewall, increasing the differential drive amount to make the fuselage rotate towards the sidewall; when Δx approaches zero, the differential drive amount approaches zero, and the fuselage maintains the current heading.

5. The off-axis control method for a transverse-axis tunneling and anchoring machine based on coordinate matching according to claim 1, characterized in that, In step S5, the preset threshold for the heading angle is: When the heading angle β exceeds the preset threshold, the output of differential drive is stopped, and only the common speed forward drive of the left and right tracks is retained; when the heading angle β is detected to start decreasing and is lower than the preset threshold, the output of differential drive is restored.

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