A drive planning method for high-speed motion mechanisms

Abstract

The present invention provides a drive planning method for a high-speed motion mechanism. The present invention plans two continuous first drive stages and second drive stages based on the maximum overshoot of inertial vibration and the duration of vibration; the first drive stage is a high-speed and high-acceleration motion drive stage; the second drive stage is a dynamic low-speed and low-acceleration S-curve drive stage. The first drive stage of the present invention still realizes rapid motion to ensure the high efficiency of the motion process; by setting a certain gap, overshoot and continuous oscillation of the positioning target due to high-speed and large inertial motion are avoided, and the motion mechanism is prevented from colliding with or damaging the positioning target; the present invention reaches the positioning target through the second drive stage, which can avoid overshoot and inertial oscillation at the final target, and can ensure that the influence of high-speed motion inertial impact on positioning accuracy is avoided, and high-precision positioning is achieved. The present invention does not extend the entire positioning operation time, and ensures the high efficiency of the entire operation.

Description

Technical Field

[0001] The invention relates to the technical field of drive planning, in particular to a drive planning method for a high-speed motion mechanism. Background Art

[0002] As manufacturing, processing, and positioning operations continue to increase their requirements for quality and efficiency, higher high-performance positioning operation requirements are placed on motion actuators. On the one hand, motion actuators need to undertake higher-speed and high-acceleration motion tasks to achieve rapid motion and ensure operational efficiency; on the other hand, they must not produce positioning overshoot, avoid inertial shock and continuous oscillation, and damage products at the positioning target position. In addition, high-precision positioning must be achieved.

[0003] It is very difficult to meet these three requirements at the same time. It is difficult to avoid overshoot due to inertial impact during high-speed positioning, and large inertial vibration will also affect positioning accuracy. How to achieve high-precision positioning without overshoot at high speed and high acceleration is a difficult problem. Conventional high-speed motion planning methods are direct one-time drive from the initial point to the target point, such as step command + tracking differentiator, trapezoidal curve and S-curve and other high-speed motion planning methods.

[0004] However, in actual operation, there are high requirements for displacement, speed and acceleration, so the method of step command + tracking differentiator is only applicable to situations where the quality and efficiency of the processing process are not high; secondly, although the trapezoidal curve takes into account the speed, acceleration and low computing power of the platform, there are still acceleration mutations or jitters in the motion process. High-speed motion planning methods such as S-curves ensure the geometric smoothness of the motion curve by further limiting indicators such as maximum acceleration, maximum speed and maximum jerk.

[0005] Therefore, the existing technology has a great inertial energy impact under high-speed movement, and it is still impossible to avoid excessive residual vibration and a long attenuation time to meet the needs of precise positioning under high-speed and high-acceleration conditions such as high-speed starting and stopping. Summary of the invention

[0006] In view of the shortcomings of the prior art, the present invention provides a drive planning method for a high-speed motion mechanism. The present invention plans two driving stages to ensure the high efficiency of the motion process while avoiding the motion mechanism from colliding with or damaging the positioning target. It can also ensure that the influence of high-speed motion inertial impact on positioning accuracy is avoided, thereby achieving high-precision positioning.

[0007] The technical solution of the present invention is: a drive planning method for a high-speed motion mechanism, the drive planning method comprising the following steps:

[0008] Starting from the maximum overshoot of inertial vibration and the vibration duration, two consecutive driving stages are planned, namely the first driving stage and the second driving stage, wherein the first driving stage is a high-speed and high-acceleration motion drive; the second driving stage is a dynamic low-speed and low-acceleration S-curve drive, and the final positioning target position is reached through the second driving stage of the dynamic low-speed and low-acceleration S-curve;

[0009] A certain gap D2 is maintained between the displacement target D1 of the first driving stage and the final positioning target D;

[0010] The start time of the second driving stage is the moment when the real-time speed in the inertial vibration during the positioning stage of the first driving stage approaches zero for the first time and the first inertial vibration amplitude approaches the peak amplitude.

[0011] As a preference, the gap D2 is formed by the maximum overshoot O generated in the first driving stage. v And the displacement protection margin P m Determine to accommodate the overshoot caused by high-speed movement and avoid overshoot and vibration interfering with the final target position.

[0012] Preferably, the initial parameters of the motion planning in the S-curve of the second drive are determined by the output of the first drive stage.

[0013] Preferably, the output condition of the first driving stage includes the maximum overshoot of the first driving stage and the vibration duration from the end of the first driving stage to the movement entering stability.

[0014] Preferably, the initial parameters of the motion planning in the second driving S-curve include the initial target displacement D2, the initial maximum speed V 2max , initial maximum acceleration value A 2max .

[0015] Preferably, the initial maximum speed V of the second driving stage is 2max Determined based on the remaining planned displacement and vibration duration of the first driving phase, and using the initial maximum velocity V of the second driving phase 2max The initial maximum acceleration value A of the second driving stage is calculated based on the vibration duration of the first driving stage. 2max .

[0016] Preferably, the second driving stage optimizes the motion planning parameters corresponding to the minimum overshoot and operation time of the second driving stage in an iterative manner through physical constraints, positioning error constraints and optimization objective function.

[0017] Preferably, the motion planning parameter iteration process of the second driving stage is specifically as follows:

[0018] S21), firstly give the planning parameter ranges of the first driving stage and the second driving stage to physically constrain the iteration parameters, initialize and assign the planning parameters;

[0019] S22), bring the planning parameters into the planning curve, and constrain the actual movement by positioning error, and calculate the operation time s from the initial position to entering the stable state t and maximum overshoot O v , the operation time s t and maximum overshoot O v Composition optimization objective function:

[0020] fitness(i)=Min(a×s t +b×O v );

[0021] Where a and b are the operation time s respectively. t and the maximum overshoot O v The weight parameter of

[0022] S23), judging the number of iterations and the objective function, if the number of iterations and the objective function meet the requirements, then jumping out of the iteration, otherwise updating the parameters and repeating step S22);

[0023] S24), when the number of iterations, overshoot and operation time meet the requirements, the iteration is stopped and the optimal planning parameters are output.

[0024] As a preferred method, according to the final positioning target position D and the motion speed, acceleration and jerk parameter limit requirements, the system point motion response law is used to optimize the planning parameters and calculate the maximum speed V in the first driving stage. 1max , maximum acceleration A 1max , limit jerk J 1max ; and set the maximum speed V 1max , maximum acceleration A 1max , limit jerk J 1max As a constraint of the first driving stage, the high-speed motion stage is planned according to the point motion.

[0025] The beneficial effects of the present invention are:

[0026] 1. The present invention plans the motion of the high-speed motion mechanism into two driving stages. The first driving stage adopts high-speed and high-acceleration motion to still achieve rapid motion and ensure the efficiency of the motion process. By setting a gap between the first driving stage and the final target position, overshoot and continuous oscillation of the positioning target due to high-speed and large inertia motion are avoided, and the motion mechanism is prevented from colliding with or damaging the positioning target.

[0027] 2. The second driving stage of the present invention adopts a low-speed and low-acceleration S-shaped curve to reach the positioning target. By reaching the positioning target at a low speed, overshoot and inertial oscillation at the final target can be avoided. The planned second driving stage sets a low-speed driving value at the start time, which can ensure that the inertial vibration of the first driving stage during the second driving stage will not interfere with the final target. In addition, the second driving stage allows the motion mechanism to reach the positioning target at a low speed, which can ensure that the influence of high-speed motion inertial impact on positioning accuracy is avoided, and high-precision positioning is achieved;

[0028] 3. The second driving stage of the present invention plans the start time by the overshoot of the first driving stage and the inertial vibration stabilization time, so that the target position can be reached when the inertial vibration of the first driving stage ends, without extending the entire positioning operation time, thereby ensuring the high efficiency of the entire operation;

[0029] 4. The present invention adopts an iterative method to automatically find the optimal motion planning parameters of the second driving stage through the maximum overshoot and operation time in the first driving stage, thereby improving the practicality and dynamics of the present invention;

[0030] 5. The present invention can automatically iterate the planning parameters corresponding to the motion effect with the minimum overshoot and operation time by integrating physical constraints, positioning error constraints and time optimal planning of planning curve design. The algorithm is simple and applicable to various CNC machine tools. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the process of the present invention;

[0032] Figure 2 Schematic diagram of the iterative process of motion planning parameters in the second driving stage of the present invention. DETAILED DESCRIPTION

[0033] The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings:

[0034] like Figure 1 As shown, this embodiment provides a drive planning method for a high-speed motion mechanism, comprising:

[0035] Based on the maximum overshoot of inertial vibration and the vibration duration, two consecutive driving stages are planned, namely the first driving stage and the second driving stage.

[0036] Among them, the first driving stage is a high-speed and high-acceleration motion drive; the second driving stage is a dynamic low-speed and low-acceleration S-curve drive, and the final positioning target position is reached through the dynamic low-speed and low-acceleration S-curve second driving stage.

[0037] In this embodiment, in order to avoid overshoot and continuous oscillation of the positioning target due to high-speed and large inertial motion, and to prevent the motion mechanism from hitting or damaging the positioning target; a certain gap D2 is maintained between the displacement target D1 of the first driving stage and the final positioning target D; in this embodiment, the gap D2 is generated by the maximum overshoot O generated in the first driving stage. v And the displacement protection margin P m Determine to accommodate the overshoot caused by high-speed movement and avoid overshoot and vibration interfering with the final target position.

[0038] In this embodiment, the start time of the second driving stage is the moment when the real-time speed in the inertial vibration of the positioning stage of the first driving stage approaches zero for the first time and the first inertial vibration amplitude approaches the peak amplitude.

[0039] As a preferred embodiment of the present invention, in the first driving stage, according to the final positioning target position D and the motion speed, acceleration and jerk parameter restriction requirements, the system point motion response law is used to optimize the planning parameters and calculate the displacement target D1 and the maximum speed V 1max , maximum acceleration A 1max , limit jerk J 1max ; and set the maximum speed V 1max , maximum acceleration A 1max , limit jerk J 1max As a constraint of the first driving stage, the high-speed motion stage is planned according to the point motion.

[0040] As a preferred embodiment of the present invention, the initial parameters of the motion planning in the second driving S-curve include the initial target displacement D2, the initial maximum speed V 2max , initial maximum acceleration value A 2max . And the initial maximum speed V of the second driving stage is 2max Determined based on the remaining planned displacement and vibration duration of the first driving phase, and using the initial maximum velocity V of the second driving phase 2max The initial maximum acceleration value A of the second driving stage is calculated based on the vibration duration of the first driving stage. 2max .

[0041] As a preferred embodiment of the present invention, the initial target displacement D2 of the second driving stage before iteration and the initial maximum speed V of the second driving stage are 2max , the initial maximum acceleration value A of the second driving stage 2max Obtained by the following formula:

[0042]

[0043] In the formula, Ov is the maximum overshoot in the first driving stage; P m Protection margin set for the second drive; s t The vibration duration from the end of the first driving stage to the time when the movement enters a stable state.

[0044] As a preferred embodiment of the present invention, the second driving stage uses physical constraints, positioning error constraints and optimization objective functions to optimize the motion planning parameters corresponding to the minimum overshoot and operation time of the second driving stage in an iterative manner.

[0045] The physical constraints of the second driving stage are:

[0046]

[0047] In the formula, A 1max and A 2max are the planned limit accelerations of the first driving stage and the second driving stage set in the plan; V max , A max and J max are the limit velocity, limit acceleration and limit jerk under the physical characteristics of the mechanism; V 1max 、V 2max are the maximum speeds set in the first driving stage and the second driving plan respectively; J 1max and J 2max is the limit jerk of the first and second driving stages set in the plan; D represents the final positioning target, D1 represents the positioning target displacement of the first driving stage, and D 2min It is the minimum second driving stage positioning target displacement under the planning parameters.

[0048] The positioning error constraint condition of the second driving stage refers to constraining the actual position change y(t) by setting the positioning accuracy δ:

[0049] y(t)-(D1+D2)|≤δ;

[0050] Where D1 and D2 are the target displacement of the first drive and the target displacement of the second drive, respectively.

[0051] As preferred in this embodiment, Figure 2 As shown, the iterative process of planning parameters in the second driving stage is specifically as follows:

[0052] S21), firstly give the planning parameter ranges of the first driving stage and the second driving stage to physically constrain the iteration parameters, initialize and assign the planning parameters;

[0053] S22), bring the planning parameters into the planning curve, and constrain the actual movement by positioning error, and calculate the operation time s from the initial position to entering the stable state t and the maximum overshoot O v , the operation time s t and the maximum overshoot O v Composition optimization objective function:

[0054] fitness(i)=Min(a×s t +b×O v );

[0055] Where a and b are the operation time s respectively. t and maximum overshoot O v The weight parameter of

[0056] S23), judging the number of iterations and the objective function, if the number of iterations and the objective function meet the requirements, then jumping out of the iteration, otherwise updating the parameters and repeating step S22);

[0057] S24), when the number of iterations, overshoot and operation time meet the requirements, the iteration is stopped and the optimal planning parameters are output.

[0058] The above embodiments and descriptions are only for illustrating the principles and best embodiments of the present invention. Without departing from the spirit and scope of the present invention, the present invention may be subject to various changes and improvements, all of which fall within the scope of the present invention to be protected.

Claims

1. A drive planning method for a high-speed motion mechanism, characterized in that: The drive planning method plans two consecutive first drive stages and second drive stages based on the maximum overshoot of inertial vibration and the vibration duration; The first driving stage is a high-speed and high-acceleration motion driving stage; The second driving stage is a dynamic low-speed and low-acceleration S-curve driving stage, and the final positioning target position is reached through the second driving stage of the dynamic low-speed and low-acceleration S-curve; A gap D2 is maintained between the displacement target D1 of the first driving stage and the final positioning target D; The start time of the second driving stage is the moment when the real-time speed in the inertial vibration of the positioning stage of the first driving stage approaches zero for the first time and the first inertial vibration amplitude approaches the peak amplitude; The initial parameters of the motion planning in the low acceleration S-curve of the second driving stage include the initial target displacement D2, the initial maximum speed V 2max , initial maximum acceleration value A 2max ; The initial maximum speed V of the second driving stage is 2max Determined based on the remaining planned displacement and vibration duration of the first driving phase, and using the initial maximum velocity V of the second driving phase 2max The initial maximum acceleration value A of the second driving stage is calculated based on the vibration duration of the first driving stage. 2max .

2. The drive planning method for a high-speed motion mechanism according to claim 1, characterized in that: The gap D2 is generated by the maximum overshoot O in the first driving stage. v And the displacement protection margin P m Sure.

3. The drive planning method for a high-speed motion mechanism according to claim 1, characterized in that: The initial parameters of the motion planning in the S-curve of the second drive are determined by the output of the first drive stage; the output of the first drive stage includes the maximum overshoot of the first drive stage and the vibration duration from the end of the first drive stage to the movement entering stability.

4. The drive planning method for a high-speed motion mechanism according to claim 1, characterized in that: The initial target displacement D2 of the second driving stage and the initial maximum speed V of the second driving stage 2max , the initial maximum acceleration value A of the second driving stage 2max Obtained by the following formula: In the formula, O v is the maximum overshoot in the first driving stage; P m Protection margin set for the second drive; s t The vibration duration from the end of the first driving stage to the time when the movement enters a stable state.

5. The drive planning method for a high-speed motion mechanism according to claim 1, characterized in that: The second driving stage uses physical constraints, positioning error constraints and optimization objective functions to optimize the motion planning parameters corresponding to the minimum overshoot and operation time of the second driving stage in a continuous iterative manner.

6. The drive planning method for a high-speed motion mechanism according to claim 5, characterized in that: The physical constraints of the second driving stage are: In the formula, A 1max and A 2max They are the planned maximum accelerations of the first driving stage and the second driving stage set in the plan respectively; V max , A max and J max are the limit velocity, limit acceleration and limit jerk under the physical characteristics of the mechanism; V 1max 、V 2max are the maximum speeds set in the first driving stage and the second driving plan respectively; J 1max and J 2max is the limit jerk of the first and second driving stages set in the plan; D represents the final positioning target, D1 represents the positioning target displacement of the first driving stage, and D 2min It is the minimum second driving stage positioning target displacement under the planning parameters.

7. The drive planning method for a high-speed motion mechanism according to claim 5, characterized in that: The positioning error constraint condition of the second driving stage refers to constraining the actual position change y(t) by setting the positioning accuracy δ: |y(t)-(D1+D2)|≤δ; Where D1 and D2 are the target displacement of the first drive and the target displacement of the second drive, respectively.

8. The drive planning method for a high-speed motion mechanism according to claim 5, characterized in that: The optimization objective function is: fitness(i)=Min(a×s t +b×O v ); Where a and b are the operation time s respectively. t and the maximum overshoot O v The weight parameter of .

9. The drive planning method for a high-speed motion mechanism according to claim 5, characterized in that: The motion planning parameter iteration process of the second driving stage is as follows: S21), firstly give the planning parameter ranges of the first driving stage and the second driving stage to physically constrain the iteration parameters, initialize and assign the planning parameters; S22), bring the planning parameters into the planning curve, and constrain the actual movement by positioning error, and calculate the operation time s from the initial position to entering the stable state t and the maximum overshoot O v , the operation time s t and the maximum overshoot O v Composition optimization objective function; S23), judging the number of iterations and the objective function, if the number of iterations and the objective function meet the requirements, then jumping out of the iteration, otherwise updating the parameters and repeating step S22); S24), when the number of iterations, overshoot and operation time meet the requirements, the iteration is stopped and the optimal planning parameters are output.

10. The drive planning method for a high-speed motion mechanism according to claim 1, characterized in that: According to the final positioning target position D and the motion speed, acceleration and jerk parameter limit requirements, the system point motion response law is used to optimize the planning parameters and calculate the D1 positioning target and the maximum speed V 1max , maximum acceleration A 1max 、Limiting jerk J 1max ; and set the maximum speed V 1max , maximum acceleration A 1max 、Limiting jerk J 1max As a constraint of the first driving stage, the high-speed motion stage is planned according to the point motion.

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