A dynamic adaptive look-ahead nested programming method

Abstract

The present invention discloses a dynamic adaptive forward nested planning method, including calculating the angle between line segments, adaptively intercepting N (N≥3) line segments of forward planning; initializing the transition arc radius; initially adjusting the radius of the first and last arcs, and adjusting the existence of the radius of adjacent arcs from front to back; using speed constraints, adjusting the radius of the first and last arcs and the forward end speed; adjusting the speed accessibility between adjacent arcs from front to back; saving all data, and judging whether the current forward look is the last forward look: if it is the last forward look, saving all data; otherwise saving the data of the first N‑2 arcs and N‑2 straight lines, storing them in a memory, waiting for interpolation by an interpolator, and putting the remaining line segments and arcs into the next forward look, so as to realize adaptive forward nested planning. The present invention utilizes a combination of adaptive forward look and nested planning, and can dynamically adjust the arc radius, improve the maximum planning speed, reduce the processing time, and improve efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of numerical control, and in particular relates to a dynamic adaptive forward-looking nested planning method. Background Art

[0002] At present, most low-end and mid-range CNC technologies basically only have linear and circular interpolation functions. The complex parts to be processed are approximated by computer-aided manufacturing software using continuous short straight lines to interpolate each trajectory to achieve the processing of complex parts. In order to achieve high-speed processing, it is necessary to add transition curves at the inflection points of the line segments, supplemented by appropriate forward path planning algorithms and speed planning algorithms to achieve high speed.

[0003] Due to the limited functions of mid- and low-end machine tools, linear and circular interpolation and linear speed planning algorithms are usually used, and efficiency can only be improved by optimizing the forward path planning algorithm. Although the forward method with a fixed number of segments achieves better results than single-segment linear acceleration and deceleration, the selection of a fixed number of segments will cut off the connection between the segments, and the information between the segments cannot be fully utilized, and it cannot adapt to the changing micro-segment situation. The adaptive forward algorithm solves the above problems. The number of segments intercepted by the adaptive forward algorithm is related to the angle value, but there is no clear research and guiding suggestions for selecting angles. The patent with publication number CN113848802A discloses a nested forward planning method, which gives a basis for angle judgment and uses a nested method to achieve continuous forward thinking. The fixed nested method does not fully utilize the angle information, reduces the speed of continuous large-angle segments, and results in limited speed improvement. Research on planning methods based on the combination of adaptive forward and nested planning helps to improve the maximum planning speed and increase the rate. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide a dynamic adaptive forward-looking nested planning method in view of the deficiencies of the above-mentioned prior art, which combines the linear acceleration and deceleration method and the arc transition method to achieve continuous forward-looking.

[0005] In order to achieve the above technical objectives, the technical solution adopted by the present invention is:

[0006] A dynamic adaptive look-ahead nested planning method, comprising:

[0007] Step 1: In the process of nested forward planning, the angle between the line segments is calculated, and N line segments for forward planning are adaptively intercepted according to the angle between the line segments, where N ≥ 3;

[0008] Step 2, initializing the transition arc radius;

[0009] Step 3, according to whether the initialized first and last arcs exist, the radius of the first and last arcs is initially adjusted, and then the radius of adjacent arcs is adjusted from front to back to see if they exist;

[0010] Step 4: According to the speed constraint, adjust the radius of the first and last arcs and the forward end speed;

[0011] Step 5: According to the speed constraint, adjust the speed accessibility between adjacent arcs from front to back;

[0012] Step 6: Save all data and determine whether the current look-ahead is the last look-ahead:

[0013] If it is the last look-ahead, all data will be saved;

[0014] Otherwise, save the data of the first N-2 arcs and N-2 straight lines, store them in memory, wait for the interpolator to interpolate, put the remaining line segments and arcs into the next look-ahead, then read the line segments, return to step 1 for the next look-ahead, and realize adaptive look-ahead nested planning.

[0015] To optimize the above technical solutions, the specific measures taken also include:

[0016] The above step 1 is specifically as follows:

[0017] In the nested look-ahead planning process, line segments are read and the angles between the line segments are calculated;

[0018] Starting from the second arc angle, when the angle value is less than or equal to 126.8699°, the line segment read previously is used as the line segment for forward planning;

[0019] If there is no situation where the angle value from the second arc angle is less than or equal to 126.8699° and there are no remaining line segments, the read line segment is used as a line segment for forward planning.

[0020] In the above step 2, the transition arc radius is initialized according to the maximum contour error and the maximum bow height error, wherein the radius of the first arc initialized is the radius of the last transition arc in the previous look-ahead. If it is the first look-ahead, the first arc is also initialized to obtain the initial value of the transition arc radius.

[0021] In step 3 above, according to whether the initialized first and last arcs exist, the radius of the first and last arcs is initially adjusted, specifically:

[0022] Project the first and last arcs onto the first and last line segments. If the length after projection is greater than the length of the first and last straight line segments, the initialized arc radius is inappropriate and needs to be adjusted.

[0023] When adjusting, the maximum speed allowed on the arc and the speed on the straight line are combined with the speed planning to accelerate to the speed equal to the speed at the connection point of the arc, and the radius of the first and last arcs are calculated and adjusted.

[0024] The above step 3 is to adjust the existence of adjacent arc radii from front to back, specifically:

[0025] Adjust the radius of the adjacent arcs in the middle so that each arc exists, meeting the requirement of the existence of the transition arc and thus meeting the condition of speed continuity;

[0026] The specific adjustment method of adjusting the radius of the adjacent arcs in the middle is as follows:

[0027] Each forward processing starts from the second arc, and each time three consecutive arcs are taken to check their projections on the two straight lines where the middle arc is located;

[0028] 1) If the sum of the lengths of the two adjacent projected line segments on the left and right straight lines is greater than the length of the straight lines, the radius of the middle arc is calculated based on the equal speeds on the adjacent arcs, and then the smaller radius is taken. If the adjusted radius is greater than the radius before adjustment, the radius of the middle arc is not adjusted, and the radius of the left and right arcs is calculated to determine the relationship between the radius and the radius before adjustment. If it is greater, it is not adjusted;

[0029] 2) If the sum of the lengths of the two adjacent projected line segments on the left or right straight line where the middle arc is located is greater than the length of the straight line, the radius of the middle arc is calculated based on the equal speeds on the adjacent arcs. If the adjusted radius is greater than the radius before adjustment, the radius of the middle arc is not adjusted. Then calculate the radius of the other arc and determine its relationship with the radius of the arc before adjustment. If it is greater, it is not adjusted.

[0030] The last judgment shows that there are only two arcs, which meets the above situation 2), so the adjustment is made according to the method of situation 2).

[0031] The above step 4 adjusts the radius of the first and last arcs according to the speed constraint, specifically:

[0032] Adjust the radius of the first and last arcs. When adjusting, calculate and adjust the radius of the first and last arcs based on the maximum speed allowed on the arc and the speed on the straight line combined with the speed planning to accelerate to the same speed as the speed at the arc connection point.

[0033] The adjustment method of the forward end speed described in step 4 above is as follows:

[0034] The speed on the arc is defined as the minimum value of the maximum allowable speed on the arc, the maximum speed under the bow height error constraint, and the maximum limited speed;

[0035] If the process from the second-to-last arc to the first-to-last arc is an acceleration process, then the forward terminal velocity is the velocity on the second-to-last arc;

[0036] If the process from the second-to-last arc to the first-to-last arc is a deceleration process, when the angle corresponding to the first-to-last arc is less than or equal to 126.8699°, the look-ahead final speed is the minimum value of the maximum allowable speed on the second-to-last arc, the maximum speed under the bow height error constraint, the maximum limited speed, and the speed from the second-to-last arc in reverse combined with speed planning to the speed at the connection point of the second-to-last arc; when the angle corresponding to the first-to-last arc is greater than 126.8699°, the look-ahead final speed is the minimum value of the maximum allowable speed on the second-to-last arc, the maximum speed under the bow height error constraint, the maximum limited speed, and the speed from the intersection of the second-to-last straight line and the second-to-last straight line, the speed from 0 in reverse combined with speed planning to the connection point of the second-to-last arc and the second-to-last straight line.

[0037] The above step 5 is specifically as follows:

[0038] Determine whether the speed from the previous arc to the next arc is an acceleration process or a deceleration process:

[0039] If it is an acceleration process, the speed planning is combined to determine whether the acceleration can be completed, that is, whether the acceleration can reach the maximum allowable speed of the next arc. If so, no adjustment is made; otherwise, the radius and speed of the next arc are adjusted.

[0040] If it is a deceleration process, first combine the speed planning to determine whether it can decelerate to the maximum allowable speed of the next arc. If it can, no adjustment will be made. Otherwise, the radius and speed of the previous arc will be adjusted.

[0041] In the above step 5, during the adjustment process from the previous arc to the next arc, if the radius of the previous arc has been adjusted, it is necessary to check from the back to the front and adjust forward until the radius of the arc does not need to be adjusted.

[0042] In the above step 6, after the current forward planning is completed, it is determined whether the current forward planning is the last forward planning: if it is the last forward planning, all data are saved; otherwise, the data of the first N-2 arcs and N-2 straight lines are saved.

[0043] The present invention has the following beneficial effects:

[0044] 1. The present invention proposes to use the critical angle to adaptively intercept the number of forward-looking segments, thereby reducing the information fragmentation between continuous large-angle line segments and effectively preserving information; the present invention not only uses the critical angle for adaptive planning, but also further combines the nested planning, combines the two, and adjusts the forward-looking final speed through the judgment of the critical angle, so that no matter how the subsequent forward-looking is adjusted, it will not affect the previous forward-looking result, and utilizes the advantages of both to achieve higher efficiency.

[0045] The difficulty of combining is that nested planning requires that the next forward-looking adjustment result will not affect the previous forward-looking result, so there is a limit on the speed input size of the next forward-looking, and the critical angle is the basis for speed adjustment. The critical angle of the existing technology does not take into account the dynamic adjustment of the transition arc radius. The nested method cannot guarantee that the next forward-looking will not affect the previous result, and naturally the critical angle will not be combined with the nested planning.

[0046] 2. The present invention proposes a method combining adaptive forward planning with nested planning, which can avoid the situation where the first and last speeds of each forward planning are both 0 in adaptive forward planning, thereby improving planning efficiency;

[0047] 3. The present invention improves the maximum speed in the path planning process and improves the processing efficiency by combining adaptive forward planning with dynamic adjustment of the transition arc radius. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a flow chart of the method of the present invention;

[0049] Figure 2 It is a schematic diagram of the arc transition model;

[0050] Figure 3 is the original path diagram;

[0051] Figure 4 transition arcs planned for contrast methods;

[0052] Figure 5 Speed ​​profiles planned for comparison methods;

[0053] Figure 6 The transition arc planned for the present invention;

[0054] Figure 7 The speed curve planned for the present invention. DETAILED DESCRIPTION

[0055] The embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings.

[0056] See also Figure 1 The present invention provides a dynamic adaptive forward nested planning method, comprising:

[0057] Step 1: In the process of nested forward planning, the angle between the line segments is calculated, and N line segments for forward planning are adaptively intercepted according to the angle between the line segments, where N ≥ 3;

[0058] In the nested look-ahead planning process, line segments are read and the angles between the line segments are calculated;

[0059] Starting from the second arc angle, when the angle value is less than or equal to 126.8699°, the line segment read previously is used as a forward planning.

[0060] If there is no condition that the angle value from the second arc angle is less than or equal to 126.8699° and there are no remaining line segments, the read line segment is used as a forward planning.

[0061] In each forward-looking model diagram, Figure 2 As shown, assuming ∠P q P r P s <126.8699°, then the forward range is from point P m-1 To point P s .

[0062] Step 2, initializing the transition arc radius;

[0063] Initialize the transition arc radius according to the maximum contour error and the maximum bow height error, where the radius of the first arc initialized is the radius of the final transition arc in the previous look-ahead. If it is the first look-ahead, the first arc is also initialized to obtain the initial value of the transition arc radius.

[0064] In the embodiment, P m-1 , P m , P n , P q are the endpoints of adjacent line segments. In order to achieve a smooth transition between adjacent line segments, the strategy of inserting arc segments is adopted, and the center point of the circle is O m , O n , with a radius of R m , R n , where O m1 , O m2 , O n1 , O n2 is the tangent point between the arc and the adjacent straight line segment, line segment P m O m Intersects the arc at point P1 and O m1 O m2 At P5, line segment P3P4 is perpendicular to P m O m , exchange P m O m At P2, the length of the line segment P1P2 Indicates the maximum interpolation speed allowed for the transition arc resulting in the bow height error e ch , line segment P2P m Length Indicates the contour error e caused by the maximum interpolation speed allowed for the transition arc co ;

[0065] The radius of the arc is:

[0066] r m =sin(θ / 2)×(e co -e ch ) / (1-sin(θ / 2))

[0067] Click P m The corresponding arc radius r and the distance projected onto the first line segment The calculation of is as follows:

[0068] r1=sin(θ1 / 2)×(e co_max -e ch_max ) / (1-sin(θ1 / 2))

[0069]

[0070] The maximum contour error allowed by the system is e co_max , the maximum bow height error allowed by the system is e ch_max , straight line segment P m- 1P m P n The angle between them is θ1.

[0071] Step 3, according to whether the initialized radius of the first and last arcs exists, the radius of the first and last arcs is initially adjusted, and then the radius of the adjacent arcs is adjusted from front to back to see if they exist;

[0072] Initial adjustment of the radius of the first and last arcs refers to projecting the first and last arcs onto the first and last line segments. If the length after projection is greater than the length of the first and last line segments, the initialized arc radius is inappropriate and needs to be adjusted. When adjusting, start from 0 based on the maximum speed allowed on the arc and the speed on the straight line, and combine the speed planning to accelerate to the speed equal to the speed at the arc connection point as a condition, calculate the radius of the first and last arcs and adjust them.

[0073] If the projection length of the last arc on the last line segment is like Then you need to adjust the radius of the arc at the end, from point P s Accelerate to point O r2 The velocity at v l , click P r The speed on the corresponding arc is v c ,but:

[0074]

[0075] v c 2 =r×a max

[0076]

[0077]

[0078] v l =v c

[0079] The radius value can be obtained by combining:

[0080]

[0081] Then, the existence of adjacent arc radii is adjusted from front to back, which means adjusting the radius of the adjacent arcs in the middle to a suitable size so that each arc exists, meets the requirement of transition arc existence, and thus meets the speed continuity condition. The specific method is:

[0082] Each forward processing starts from the second arc, and each time three consecutive arcs are taken to check their projections on the two straight lines where the middle arc is located.

[0083] 1) If the sum of the lengths of the two adjacent projected line segments on the left and right straight lines is greater than the length of the straight lines, the radius of the middle arc is calculated based on the equal speeds on the adjacent arcs, and then the smaller radius is taken. If the adjusted radius is greater than the radius before adjustment, the radius of the middle arc is not adjusted, and the radii of the left and right arcs are calculated respectively to determine their relationship with the radius of the arc before adjustment. If it is greater than the radius before adjustment, it is not adjusted.

[0084] 2) If the sum of the lengths of the two adjacent projected line segments on the left straight line or the right straight line where the middle arc is located is greater than the length of the straight line, the radius of the middle arc is calculated based on the equal speeds on the adjacent arcs. If the adjusted radius is greater than the radius before adjustment, the radius of the middle arc is not adjusted. Then calculate the radius of another arc and determine its relationship with the radius of the arc before adjustment. If it is greater, it is not adjusted.

[0085] The last judgment shows that there are only two arcs, which meets the above situation 2). Adjust according to the method of situation 2).

[0086] Assume that the point currently being processed is P q The corresponding arc is P n , P q , P r The arcs corresponding to the three points, and the projection lengths of the three arcs are and The adjustment steps are as follows:

[0087] First, P n , P q The arc speeds corresponding to the two points are equal

[0088] v n2 =a max × n

[0089]

[0090]

[0091]

[0092] v n =v 1 q

[0093]

[0094] We can get:

[0095] Among them, v n It's point P n The kinematic limit speed of the point on the arc, r n It's point P n The point corresponds to the radius of the arc; v 1 q It's point P q The kinematic limit speed of the point on the arc, r q 1 It's point P q The radius of the arc corresponding to the point

[0096] Secondly q , P r The arc speeds corresponding to the two points are equal

[0097]

[0098]

[0099] v r 2 =a max × r

[0100]

[0101] v 11 q =r r

[0102]

[0103] We can get:

[0104] Among them, r 11q It's point P q The radius of the arc corresponding to the point, v 11 q YesP q The kinematic limit speed of the point on the arc; r r YesP r The radius of the arc corresponding to the point, v r YesP r Kinematic limit speed of the point on the arc

[0105] make If the adjusted projection value is greater than the projection value before adjustment, adjust it to the original corresponding projection value and calculate the arc radius. The projection values ​​corresponding to the other two arcs are: If the adjusted projection value is greater than the projection value before adjustment, it is adjusted to the original corresponding projection value and the corresponding arc radius is calculated.

[0106] Step 4: According to the speed constraint, adjust the radius of the first and last arcs and the forward end speed;

[0107] The first and last arcs are projected onto the first and last line segments. The length after projection is less than the length of the straight line, but the speed obtained by the arc is lower. If the adjustment conditions are met, in order to obtain higher speed and efficiency, the radius of the first and last arcs is adjusted. The adjustment method is the same as the initial adjustment of the radius of the first and last arcs in step 3.

[0108] Solve the forward terminal velocity, that is, point P q The corresponding velocity v on the arc q The remaining line segments and arcs are used as the data for the next nested look-ahead. The final speed of the look-ahead guarantees point P. r The corresponding arc can be passed no matter how it is adjusted, and then connected to the next look-ahead. The specific method is as follows:

[0109] The speed on the arc is the minimum of the maximum allowable speed on the arc, the maximum speed under the bow height error constraint, and the maximum limited speed. The maximum limited speed is v max , the maximum permissible speed on the arc is The maximum speed under the bow height error constraint is Then v=min(v max ,v max ,v err ).

[0110] In the above formula, Ts is the interpolation period, r is the arc radius, e ch_max Bow height error.

[0111] If from point P q The corresponding arc to point P rThe corresponding arc is an acceleration process, so the forward end velocity is point P q The speed on the corresponding arc;

[0112] If from point P q The corresponding arc to point P r The corresponding arc is the deceleration process, point P r When the angle of the corresponding arc is less than or equal to 126.8699°, the forward terminal velocity is the maximum allowable velocity on the penultimate arc, the maximum velocity under the bow height error constraint, the maximum limited velocity, and the velocity from the penultimate arc along the straight line P q P r Reverse speed planning to accelerate to the connection point O of the second to last arc and the second to last straight line q2 The speed at point P is the minimum value among the four. r When the angle of the corresponding arc is greater than 126.8699°, the forward terminal velocity is the maximum allowable velocity on the penultimate arc, the maximum velocity under the bow height error constraint, the maximum limited velocity, and the intersection of the penultimate straight line and the penultimate straight line, i.e., point P. r At the point, the velocity changes from 0 along the straight line P q P r Reverse speed planning to accelerate to the connection point O of the second to last arc and the second to last straight line q2 The speed at , the minimum of the four.

[0113] Step 5: According to the speed constraint, adjust the speed accessibility between adjacent arcs from front to back;

[0114] Determine whether the speed from the previous arc to the next arc is an acceleration process or a deceleration process: If it is an acceleration process, then determine whether it can be accelerated to the maximum allowable speed of the next arc in combination with the speed planning. If it can, then do not make adjustments. Otherwise, adjust the radius and speed of the next arc. If it is a deceleration process, first determine whether it can be decelerated to the maximum allowable speed of the next arc in combination with the speed planning. If it can, then do not make adjustments. Otherwise, adjust the radius and speed of the previous arc, and adjust back to the point where no adjustment is required. The specific method is as follows:

[0115] If the current judgment is from point P n The corresponding arc to point P q The corresponding arc is an acceleration process and can be accelerated to the right position, then the arc radius is not adjusted. If the acceleration is not in place, then the arc radius is adjusted according to the acceleration from point P. n The corresponding arc is accelerated to point P in combination with the speed planning q The corresponding arc and straight line P n P q The intersection point O q1 At the point where the two velocities are equal, find the point Pq The corresponding arc radius and adjust the speed;

[0116] If it is a deceleration process, determine whether it can be reached by deceleration. If it can be reached, no adjustment is required. If it cannot be reached, adjustment is required. The adjustment method is the same as the adjustment during the acceleration process, and the adjustment is performed in the reverse direction. It is necessary to check from back to front and adjust forward until the arc radius does not need to be adjusted. Point to P n After the corresponding arc radius is adjusted, check to avoid affecting the previously adjusted information, and use the speed planning conditions to make reverse adjustments. Repeat step 5, check from back to front, and stop the check operation if a certain arc does not need to be adjusted.

[0117] Step 6: Save all data and determine whether the current look-ahead is the last look-ahead:

[0118] If the current look-ahead is the last look-ahead, save all data. Otherwise, save the data of the first N-2 arcs and N-2 straight lines, that is, from point P m-1 To point O q2 The data between points O and 3 are stored in the memory and wait for the interpolator to interpolate. The remaining data is saved, that is, from point O q2 To point P s , then read the line segment and return to step 1 for the next look-ahead to achieve adaptive look-ahead nested planning.

[0119] Example effect verification:

[0120] Set the maximum allowable speed in Cartesian space to 100 mm / s and the maximum acceleration to 1000 mm / s 2 , the maximum contour error is 0.05mm, the maximum bow height error is 0.01mm, the interpolation cycle is 1ms, and the path to be planned Figure 3 The point data of the path to be planned is shown in Table 1. Figure 4-5 For the processing results using the comparison method, Figure 6-7 The speed curve diagram during the planning process is shown in Figure 2. Figure 5 , Figure 7 As shown, it can be seen that the maximum speed planned by the method of the present invention is higher and the number of speed fluctuations is less. To plan the same path, the comparison method takes 576ms, while the method of the present invention takes 490ms, and the efficiency is improved by: (576-490) / 490×100%=17.5%, and the maximum speed obtained by the method of the present invention is higher than that of the comparison method. The overall time consumption is shorter and the speed is higher.

[0121] Table 1 Point data of the path to be planned

[0122] Serial number X(mm) Y(mm) Length(mm) 1 5.549 1.904 2 6.348 2.023 0.808 3 7.060 2.143 0.722 4 7.668 2.265 0.620 5 8.157 2.389 0.504 6 8.510 2.516 0.375 7 8.712 2.645 0.240 8 8.747 2.777 0.137 9 8.531 2.947 0.275 10 8.139 3.089 0.417 11 7.587 3.234 0.571 12 6.910 3.383 0.693 13 6.144 3.535 0.781 14 5.325 3.689 0.833 15 4.490 3.847 0.850 16 3.675 4.007 0.831 17 2.915 4.170 0.777 18 2.246 4.335 0.689 19 1.705 4.503 0.566 20 1.327 4.673 0.414 21 1.141 4.888 0.284 22 1.238 5.053 0.191 23 1.523 5.219 0.330 24 1.962 5.386 0.470 25 2.524 5.555 0.587 26 3.176 5.723 0.673 27 3.886 5.892 0.730 28 4.622 6.061 0.755 29 5.353 6.229 0.750 30 6.046 6.397 0.713

[0123] By combining adaptive foresight with nested planning and incorporating dynamic planning of transition arcs, the processing speed is increased, the processing time is shortened, and the processing efficiency is improved.

[0124] The above are only preferred embodiments of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should be regarded as the protection scope of the present invention.

Claims

1. A dynamic adaptive forward nested planning method, characterized in that: include: Step 1: In the process of nested forward planning, the angle between the line segments is calculated, and N line segments for forward planning are adaptively intercepted according to the angle between the line segments, where N ≥ 3; Step 2, initializing the transition arc radius; Step 3, initially adjusting the radius of the first and last arcs according to the initialized first and last transition arcs, and then adjusting the radius of adjacent arcs from front to back for their existence; Step 4: According to the speed constraint, adjust the radius of the first and last arcs and the forward end speed; Step 5: According to the speed constraint, adjust the speed accessibility between adjacent arcs from front to back; Step 6: Save all data and determine whether the current look-ahead is the last look-ahead: If it is the last look-ahead, all data will be saved; Otherwise, save the data of the first N-2 arcs and N-2 straight lines, store them in memory, wait for the interpolator to interpolate, put the remaining line segments and arcs into the next look-ahead, then read the line segments, return to step 1 for the next look-ahead, and realize adaptive look-ahead nested planning; The step 1 is specifically as follows: In the nested look-ahead planning process, line segments are read and the angles between the line segments are calculated; Starting from the second arc angle, when the angle value is less than or equal to 126.8699°, the line segment read previously is used as the line segment for forward planning; If there is no situation where the angle value from the second arc angle is less than or equal to 126.8699° and there is no remaining line segment, the read line segment is used as the line segment for a forward planning; The step 3 is to adjust the radius of the first and last arcs according to the initialized first and last transition arcs, specifically: Project the first and last arcs onto the first and last line segments. If the length after projection is greater than the length of the first and last straight line segments, the initialized arc radius is inappropriate and needs to be adjusted. When adjusting, the maximum speed allowed on the arc and the speed on the straight line are combined with the speed planning to accelerate to the speed equal to the speed at the arc connection point, and the radius of the first and last arcs are calculated and adjusted.

2. A dynamic adaptive forward nested planning method according to claim 1, characterized in that: The step 2 initializes the transition arc radius according to the maximum contour error and the maximum bow height error, wherein the radius of the first arc initialized is the radius of the last transition arc in the previous look-ahead. If it is the first look-ahead, the first arc is also initialized to obtain the initial value of the transition arc radius.

3. A dynamic adaptive forward nested planning method according to claim 1, characterized in that: The adjustment of the existence of adjacent arc radii from front to back described in step 3 is specifically as follows: Adjust the radius of the adjacent arcs in the middle so that each arc exists, meeting the requirement of the existence of the transition arc and thus meeting the condition of speed continuity; The specific adjustment method of adjusting the radius of the adjacent arcs in the middle is as follows: Each forward processing starts from the second arc, and each time three consecutive arcs are taken to check their projections on the two straight lines where the middle arc is located; 1) If the sum of the lengths of the two adjacent projected line segments on the left and right straight lines is greater than the length of the straight lines, the radius of the middle arc is calculated based on the equal speeds on the adjacent arcs, and then the smaller radius is taken. If the adjusted radius is greater than the radius before adjustment, the radius of the middle arc is not adjusted, and the radius of the left and right arcs is calculated to determine the relationship between the radius and the radius before adjustment. If it is greater, it is not adjusted; 2) If the sum of the lengths of the two adjacent projected line segments on the left or right straight line where the middle arc is located is greater than the length of the straight line, the radius of the middle arc is calculated based on the equal speeds on the adjacent arcs. If the adjusted radius is greater than the radius before adjustment, the radius of the middle arc is not adjusted. Then calculate the radius of the other arc and determine its relationship with the radius of the arc before adjustment. If it is greater, it is not adjusted. The last judgment shows that there are only two arcs, which meets the above situation 2), so the adjustment is made according to the method of situation 2).

4. A dynamic adaptive forward nested planning method according to claim 1, characterized in that: According to the speed constraint described in step 4, the radius of the first and last arcs is adjusted as follows: Adjust the radius of the first and last arcs. When adjusting, calculate and adjust the radius of the first and last arcs based on the maximum speed allowed on the arc and the speed on the straight line combined with the speed planning to accelerate to the same speed as the speed at the arc connection point.

5. A dynamic adaptive forward nested planning method according to claim 1, characterized in that: The adjustment method of the forward end speed described in step 4 is as follows: The speed on the arc is defined as the minimum value of the maximum allowable speed on the arc, the maximum speed under the bow height error constraint, and the maximum limited speed; If the process from the second-to-last arc to the first-to-last arc is an acceleration process, then the forward terminal velocity is the velocity on the second-to-last arc; If the process from the second-to-last arc to the first-to-last arc is a deceleration process, when the angle corresponding to the first-to-last arc is less than or equal to 126.8699°, the look-ahead final speed is the minimum value of the maximum allowable speed on the second-to-last arc, the maximum speed under the bow height error constraint, the maximum limited speed, and the speed from the second-to-last arc in reverse combined with speed planning to the speed at the connection point of the second-to-last arc; when the angle corresponding to the first-to-last arc is greater than 126.8699°, the look-ahead final speed is the minimum value of the maximum allowable speed on the second-to-last arc, the maximum speed under the bow height error constraint, the maximum limited speed, and the speed from the intersection of the second-to-last straight line and the second-to-last straight line, the speed from 0 in reverse combined with speed planning to the connection point of the second-to-last arc and the second-to-last straight line.

6. A dynamic adaptive forward nested planning method according to claim 1, characterized in that: The step 5 is specifically as follows: Determine whether the speed from the previous arc to the next arc is an acceleration process or a deceleration process: If it is an acceleration process, the speed planning is combined to determine whether the acceleration can be completed, that is, whether the acceleration can reach the maximum allowable speed of the next arc. If so, no adjustment is made; otherwise, the radius and speed of the next arc are adjusted. If it is a deceleration process, first combine the speed planning to determine whether it can decelerate to the maximum allowable speed of the next arc. If it can, no adjustment will be made. Otherwise, the radius and speed of the previous arc will be adjusted.

7. A dynamic adaptive forward nested planning method according to claim 1, characterized in that: In step 5, during the adjustment process from the previous arc to the next arc, if the radius of the previous arc has been adjusted, it is necessary to check from the back to the front and adjust forward until the radius of the arc does not need to be adjusted.

8. A dynamic adaptive forward nested planning method according to claim 1, characterized in that: In step 6, after the current forward planning is completed, it is determined whether the current forward planning is the last forward planning: if it is the last forward planning, all data are saved; otherwise, the data of the first N-2 arcs and N-2 straight lines are saved.

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