Drive planning method for high-speed motion mechanism

Abstract

Provided in the present invention is a drive planning method for a high-speed motion mechanism. In the present invention, two consecutive drive phases, i.e., a first drive phase and a second drive phase, are planned on the basis of the maximum overshoot of inertial vibration and a vibration duration. The first drive phase is a high-speed and high-acceleration motion drive phase; and the second drive phase is a dynamic low-speed and low-acceleration S-curve drive phase. In the first drive phase in the present invention, high-speed motion is still achieved, ensuring high efficiency of the motion; and by means of setting a certain clearance, overshoot and sustained oscillation of a positioning target that are caused by a high-speed and high-inertia motion are avoided, thereby preventing the motion mechanism from colliding with or damaging the positioning target. In the present invention, the positioning target is reached via the second drive phase, such that overshoot and inertial oscillation at a final target can be avoided, and thus the influence of inertial impact caused by high-speed motion on positioning accuracy can be prevented, so as to realize high-precision positioning. Moreover, the present invention does not prolong the overall positioning operation time, thereby ensuring high efficiency of the overall operation.

Description

Driving planning method of high-speed motion mechanism TECHNICAL FIELD

[0001] The present application relates to the technical field of driving planning, in particular to a driving planning method of high-speed motion mechanism. BACKGROUND

[0002] With the continuous improvement of the quality and efficiency requirements of manufacturing, processing and positioning operations, higher performance positioning operation requirements are put forward for the motion execution mechanism. On the one hand, the motion mechanism needs to undertake higher speed and higher acceleration motion tasks to realize fast motion and ensure operation efficiency; on the other hand, it cannot produce positioning overshoot to avoid inertia impact and continuous oscillation, which damages the product at the positioning target position, in addition, it also needs to realize high-precision positioning.

[0003] It is very difficult to meet these three requirements at the same time. Positioning inertia impact at high speed leads to unavoidable overshoot, and large inertia vibration also affects the positioning accuracy. How to realize high-precision positioning without overshoot at high speed and high acceleration is a difficult problem. The conventional high-speed motion planning method is a direct one-time driving from the initial point to the target point, such as step command + tracking differentiator, trapezoidal curve and S-type curve high-speed motion planning method.

[0004] However, in actual operation, there are higher index requirements for displacement, speed and acceleration, so the step command + tracking differentiator method is only applicable to the case where the quality and efficiency requirements of the processing process are not high; secondly, although the trapezoidal curve considers the speed, acceleration and platform low power problems, the motion process still has acceleration mutation or jitter phenomenon. The S-type curve high-speed motion planning method further limits the maximum acceleration, maximum speed and maximum jerk to ensure the geometric smoothness of the motion curve.

[0005] Therefore, the prior art has a great influence on inertia energy at high speed, and still cannot avoid producing excessive residual vibration and needs a long decay time to meet the demand of precise positioning in the case of high-speed start-stop and high acceleration. SUMMARY

[0006] In view of the shortcomings of the prior art, the present application provides a driving planning method of high-speed motion mechanism. The present application plans two driving stages to ensure the efficiency of the motion process, avoid the impact or damage of the positioning target of the motion mechanism, and ensure the influence of high-speed motion inertia impact on the positioning accuracy, and realize high-precision positioning.

[0007] The technical scheme of the present application is as follows: a driving planning method of high-speed motion mechanism, the driving planning method comprises the following steps:

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

[0009] And the displacement target D1 of the first driving stage and the final positioning target D keep a certain gap D2.

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

[0011] As preferred, the gap D2 is the maximum overshoot O v generated by the first driving stage m And the set displacement protection margin P

[0012] is determined to accommodate the overshoot caused by high-speed motion, avoid overshoot and vibration interference with the final target position.

[0013] As preferred, the initial parameters of the motion planning in the S-curve of the second driving are determined by the output of the first driving stage.

[0014] As preferred, the output of the first driving stage includes the maximum overshoot of the first driving stage, the vibration duration from the end of the first driving stage to the motion entering the stable state.

[0015] As preferred, the initial parameters of the motion planning in the S-curve of the second driving include the initial target displacement D2 of the second driving stage, the initial maximum speed V 2max , and the initial maximum acceleration value A 2max .

[0016] As preferred, the initial maximum speed V 2max of the second driving stage is determined according to the remaining planned displacement and vibration duration of the first driving stage, and the initial maximum acceleration value A 2max of the second driving stage is calculated using the initial maximum speed V 2max of the second driving stage and the vibration duration of the first driving stage.

[0017] As preferred, the motion planning parameters of the second driving stage are iteratively optimized in the following process:

[0018] S21) First, give the planning parameter range of the first driving stage and the second driving stage to apply physical constraints to the iteration parameters, initialize and assign the planning parameters;

[0019] S22) Substitute the planning parameters into the planning curve and impose positioning error constraints on the actual motion to calculate the operation time s from the initial position to entering the steady state. t and maximum overshoot O v The operation time s t and maximum overshoot O v The optimization objective function is: fitness(i) = Min(a × s) t +b×O v );

[0020] In the formula, a and b are the operation times s, respectively. t and maximum overshoot O v Weight parameters;

[0021] S23) Determine the number of iterations and the objective function. If the number of iterations and the objective function meet the requirements, exit the iteration; otherwise, update the parameters and repeat step S22.

[0022] S24) Stop iterating when the number of iterations, overshoot, and operation time meet the requirements, and output the optimal planning parameters.

[0023] Preferably, based on the final target location D and the constraints on motion speed, acceleration, and jerk parameters, the planning parameters are optimized using the system's point motion response characteristics, and the maximum speed V in the first driving phase is calculated. 1max Maximum acceleration A 1max Limiting jerk J 1max ; and 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-to-point movement.

[0024] The beneficial effects of this invention are as follows:

[0025] 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 caused by high-speed and large inertia motion are avoided, and the motion mechanism is prevented from hitting or damaging the positioning target.

[0026] 2、The second driving stage of the application adopts a low-speed and low-acceleration S-shaped curve to reach the positioning target, and by reaching the positioning target at a low speed, overshoot and inertial oscillation at the final target can be avoided, and the second driving stage is set with a low-speed driving value at the starting time, which can ensure that the inertial vibration of the first driving stage does not interfere with the final target, and by the second driving stage, the motion mechanism reaches the positioning target at a low speed, which can ensure that the influence of high-speed motion inertia impact on positioning accuracy is avoided, and high-precision positioning is achieved.

[0027] 3、The second driving stage of the application plans the starting time through the overshoot amount and inertial vibration stabilization time of the first driving stage, which can reach the target position when the inertial vibration of the first driving stage ends, does not prolong the entire positioning operation time, and ensures the high efficiency of the entire operation.

[0028] 4、The application adopts an iterative method to automatically find the optimal motion planning parameters of the second driving stage through the maximum overshoot amount and operation time of the first driving stage, improving the practicality and dynamics of the application.

[0029] 5、The application can automatically iterate out the planning parameters corresponding to the motion effect with the minimum overshoot amount and operation time through the time-optimal planning of comprehensive physical constraints, positioning error constraints and planning curve design, the algorithm is simple, and is suitable for various numerical control machine tools. BRIEF DESCRIPTION OF DRAWINGS

[0030] Fig. 1 is a flowchart of the method of the application;

[0031] Fig. 2 is an iterative flowchart of the motion planning parameters of the second driving stage of the application. DETAILED DESCRIPTION

[0032] The specific embodiments of the application will be further described below in combination with the drawings:

[0033] As shown in Fig. 1, the embodiment provides a driving planning method of a high-speed motion mechanism, which comprises:

[0034] Starting from the maximum overshoot amount and vibration duration of inertial vibration, two consecutive driving stages are planned, which are the first driving stage and the second driving stage.

[0035] Among them, the first driving stage is a high-speed and high-acceleration motion driving; the second driving stage is a dynamic low-speed and low-acceleration S-shaped curve driving, and reaches the final positioning target position through the dynamic low-speed and low-acceleration S-shaped second driving stage.

[0036] In this embodiment, in order to avoid overshoot and sustained oscillation to the positioning target due to high-speed and large inertia movement, and to avoid the movement mechanism from colliding with 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 the maximum overshoot O v and the set displacement protection margin P m is determined to accommodate the overshoot caused by high-speed movement, and to avoid the overshoot and vibration from interfering with the final target position.

[0037] In this embodiment, the start time of the second driving stage is when the real-time speed in the inertial vibration of the first driving stage positioning stage approaches zero for the first time and the first inertial vibration amplitude approaches the amplitude peak.

[0038] As preferred in this embodiment, in the first driving stage, according to the final positioning target position D and the movement speed, acceleration and jerk parameter limit requirements, the system point position movement response law is used to plan and optimize the parameters, to calculate the displacement target D1, maximum speed V 1max , maximum acceleration A 1max , and limit jerk J 1max of the first driving stage; and the maximum speed V 1max , maximum acceleration A 1max , and limit jerk J 1max are used as the limit conditions of the first driving stage to plan the high-speed movement stage according to the point position movement.

[0039] As preferred in this embodiment, the initial parameters of the movement planning in the second driving S-shaped curve include the initial target displacement D2, initial maximum speed V 2max , and initial maximum acceleration value A 2max of the second driving stage. And the initial maximum speed V 2max of the second driving stage is determined according to the remaining planning displacement and vibration duration of the first driving stage, and the initial maximum acceleration value A 2max of the second driving stage is calculated using the initial maximum speed V 2max of the second driving stage and the vibration duration of the first driving stage.

[0040] As preferred in this embodiment, the initial target displacement D2 of the second driving stage before iteration, and the initial maximum speed V 2max and initial maximum acceleration value A 2max of the second driving stage are obtained by the following formula:

[0041] In the formula, O v is the maximum overshoot of the first driving stage; and Pm a protection margin for the second driving stage; s t a vibration duration from the end of the first driving stage to the motion entering a stable state.

[0042] As preferred in the embodiment, the second driving stage is optimized by physical constraints, positioning error constraints and optimization objective functions in a continuous iteration manner to find the motion planning parameters corresponding to the minimum overshoot and operation time of the second driving stage.

[0043] The physical constraints of the second driving stage are:

[0044] In the formula, A 1max and A 2max are the planning limit accelerations of the first driving stage and the second driving stage respectively set in the planning; V max , A max and J max are the limit speed, 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 planning respectively; J 1max and J 2max are the limit jerk of the first driving stage and the second driving stage set in the planning; D represents the final positioning target, D1 represents the positioning target displacement of the first driving stage, and D 2min is the minimum second driving stage positioning target displacement under the planning parameters.

[0045] The positioning error constraints of the second driving stage means that the actual position change y(t) is subjected to positioning error constraints by setting the positioning accuracy δ: |y(t)-(D1+D2)|≤δ.

[0046] In the formula, D1 and D2 are the target displacements of the first driving and the second driving respectively.

[0047] As preferred in the embodiment, as shown in FIG. 2, the iteration process of the planning parameters of the second driving stage is as follows:

[0048] S21), first set the planning parameter range of the first driving stage and the second driving stage to physically constrain the iteration parameters, initialize and assign the planning parameters;

[0049] S22), bring the planning parameters into the planning curve, and subject the actual motion to positioning error constraints, calculate the operation time s t and the maximum overshoot O v from the initial position to the entering of the stable state, and the operation time s tand maximum overshoot O v Optimization objective function of composition: fitness(i)=Min(a×s t +b×O v );

[0050] In the formula, a, b are weight parameters of operation time s t and maximum overshoot O v ;

[0051] S23), determine the iteration number and objective function, if the iteration number and objective function meet the requirements, then jump out of iteration, otherwise update parameters and repeat step S22);

[0052] S24), stop iteration when the iteration number, overshoot and operation time meet the requirements, and output the optimal planning parameters.

[0053] The above embodiments and descriptions described in the specification are only to illustrate the principles and best embodiments of the present application, and various changes and improvements can be made without departing from the spirit and scope of the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A driving planning method of a high-speed motion mechanism, characterized by comprising: The driving planning method plans two continuous first driving stage and second driving stage from the maximum overshoot and vibration duration of inertial vibration; 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; The displacement target D1 of the first driving stage and the final positioning target D maintain a certain gap D2; The starting time of the second driving stage is the time when the real-time speed in the inertial vibration of the first driving stage positioning stage approaches zero for the first time and the first inertial vibration amplitude approaches the amplitude peak; The initial parameters of the motion planning in the second driving S-shaped curve include an initial target displacement D2, an initial maximum speed V 2max , and an initial maximum acceleration value A 2max of the second driving stage. Wherein, the initial maximum speed V 2max According to the remaining planning displacement and vibration duration of the first driving stage, and using the initial maximum speed V 2max And the initial maximum acceleration value A of the second driving stage is calculated 2max .

2. The method of claim 1, wherein: The gap D2 is determined by the maximum overshoot O generated by the first driving phase v and the set displacement protection margin P m determined.

3. The method of claim 1, wherein: The initial parameters of the motion planning in the S-curve of the second driving are determined by the output of the first driving stage; the output of the first driving stage includes the maximum overshoot of the first driving stage, the vibration duration from the end of the first driving stage to the motion entering the stable state.

4. The method of claim 1, wherein: an initial target displacement D2 of the second driving phase, and an initial maximum velocity V 2max an initial maximum acceleration value A of the second driving phase 2max is obtained by the following equation: wherein O v is the maximum overshoot for the first drive phase; P m is the protection margin for the second drive setting; s t is the duration of the oscillation from the end of the first drive phase until the motion enters a stable state.

5. The method of claim 1, wherein: The second driving stage continuously iterates to optimize the motion planning parameters corresponding to the minimum overshoot and operation time of the second driving stage through physical constraint conditions, positioning error constraint conditions and optimization objective functions.

6. The method of claim 5, wherein: The physical constraint condition of the second driving stage is: In the formula, A 1max and A 2max are the planning maximum accelerations of the first driving phase and the second driving phase, respectively, set in the planning. V max , A max and J max are the limit speed, limit acceleration and limit jerk under the physical characteristics of the mechanism, respectively; V 1max , V 2max are the maximum speed set in the first driving stage and the second driving planning, respectively; J 1max and J 2max are the limit jerk of the first driving stage and the second driving stage set in the planning; D represents the final positioning target, D1 represents the positioning target displacement of the first driving stage, D 2min is the minimum second driving stage positioning target displacement under the planning parameters.

7. The method of claim 5, wherein: The positioning error constraint condition of the second driving stage is that the actual position change y(t) is subjected to positioning error constraint by setting the positioning accuracy δ: |y(t)-(D1+D2)|≤δ; In the formula, D1 and D2 are the target displacement of the first driving and the target displacement of the second driving respectively.

8. The method of claim 5, wherein: The optimization objective function is: fitness(i)=Min(a x s t +b x O v ); In the formula, a, b are weight parameters of operation time s t and maximum overshoot O v respectively.

9. The method of claim 5, wherein: The motion planning parameter iteration process of the second driving stage is as follows: S21), first give the planning parameter range of the first driving stage and the second driving stage to constrain the iteration parameters, initialize and assign the planning parameters; S22), bringing the planning parameters into the planning curve and calculating the operation time s from the initial position to the entering of the stable state with the positioning error constraint on the actual movement t and the maximum overshoot O v , the operation time s t and the maximum overshoot O v make up the optimization objective function; S23), judge the iteration number and the objective function, if the iteration number and the objective function meet the requirements, then jump out of the iteration, otherwise update the parameters and repeat step S22); S24), stop iteration when the iteration number, overshoot and operation time meet the requirements, and output the optimal planning parameters.

10. The method of claim 1, wherein: Based on the final target location D and the constraints on motion velocity, acceleration, and jerk parameters, the planning parameters are optimized using the system's point motion response characteristics. The D1 target location and maximum velocity V are calculated for the first driving phase. 1max Maximum acceleration A 1max Limiting jerk J 1max ; and will the maximum speed degrees V 1max maximum acceleration A 1max limit jerk J 1max as a limiting condition of the first driving stage, The high-speed motion stage is planned according to the point motion.

Images