CN116560359A - Improved robot trapezoidal speed curve planning method and system - Google Patents

Abstract

The invention provides an improved robot trapezoidal speed curve planning method and system, comprising the following steps: acquiring a trapezoidal speed curve in the motion planning of the robot, wherein the trapezoidal speed curve comprises an acceleration stage and a deceleration stage; and the acceleration stage and the deceleration stage control the acceleration and deceleration operation in the movement of the robot according to a preset parabolic curve. The discontinuity of the trapezoid speed curve is improved through the smoothness of the parabola, the speed curve of the robot is smoother, the realization is simple, and the practical application value is good.

Description

An improved robot trapezoidal velocity curve planning method and system

technical field

The invention belongs to the technical field related to robot motion planning, and in particular relates to an improved robot trapezoidal velocity curve planning method and system.

Background technique

The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

Trapezoidal speed curve is one of the most commonly used speed planning methods in manipulator control. It is simple and easy to implement, and it can also achieve fast feed motion. However, there are some disadvantages in this speed planning method, one of which is that there is a discontinuous acceleration in the trapezoidal speed profile, which may cause shock and stress on the mechanical system during the rapid feed motion. When the arm accelerates from rest to its maximum velocity, there is a sudden change in acceleration, which causes shock and stress to the arm's components and structure. This impact and pressure may cause damage to the components and structure of the robot arm, resulting in a shortened life of the robot arm. In addition, discontinuous acceleration can also cause undesirable vibration effects in the robotic arm, which can affect the accuracy and performance of the robotic arm.

Contents of the invention

In order to overcome the deficiencies of the prior art above, the present invention provides an improved robot trapezoidal speed curve planning method and system, which improves the discontinuity of the trapezoidal speed curve through the smoothness of the parabola and achieves a smoother robot speed curve.

To achieve the above object, the first aspect of the present invention provides an improved robot trapezoidal speed curve planning method, including:

Determine the acceleration phase and deceleration phase of the speed curve based on the initial speed, termination speed, and maximum speed in robot motion planning;

In the acceleration phase, the motion of the robot is controlled in a way that the acceleration changes with the acceleration time;

In the deceleration phase, the motion of the robot is controlled in a way that the acceleration changes with the deceleration time.

A second aspect of the present invention provides an improved robot trapezoidal velocity curve planning system, comprising:

Determination module: determine the acceleration phase and deceleration phase of the speed curve based on the initial speed, termination speed, and maximum speed in robot motion planning;

Acceleration control module: control the movement of the robot in a way that the acceleration changes with the acceleration time;

Deceleration control module: Control the movement of the robot by changing the acceleration with the deceleration time.

A third aspect of the present invention provides a computer device, including: a processor, a memory, and a bus, the memory stores machine-readable instructions executable by the processor, and when the computer device is running, the processor communicates with The memories communicate with each other through the bus, and when the machine-readable instructions are executed by the processor, an improved robot trapezoidal speed curve planning method is executed.

A fourth aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, and when the computer program is executed by a processor, an improved trapezoidal velocity curve planning method for a robot is executed.

The above one or more technical solutions have the following beneficial effects:

In the present invention, the acceleration phase and the deceleration phase of the trapezoidal speed curve are improved, and the acceleration in the acceleration phase and the acceleration in the deceleration phase are constantly changed with the change of the acceleration time and the deceleration time, thereby improving the discontinuity of the trapezoidal speed curve, The speed curve of the robot is smoother, the realization is simple, and it has good practical application value.

Advantages of additional aspects of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

Description of drawings

The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention, and the schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations to the present invention.

1 is a schematic diagram of an improved trapezoidal speed curve in Embodiment 1 of the present invention;

Fig. 2(a) is a schematic diagram of position, velocity and acceleration curve planning when q ₀ =0, q ₁ =5 in Embodiment 1 of the present invention;

Fig. 2(b) is a schematic diagram of position, velocity and acceleration curve planning when q ₀ =0, q ₁ =-5 in Embodiment 1 of the present invention;

Fig. 2(c) is a schematic diagram of position, velocity and acceleration curve planning when q ₀ =5, q ₁ =0 in Embodiment 1 of the present invention;

Fig. 2(d) is a schematic diagram of position, velocity and acceleration curve planning when q ₀ =5, q ₁ =-5 in Embodiment 1 of the present invention;

Figure 2(e) is a schematic diagram of position, velocity and acceleration curve planning when q ₀ =-5, q ₁ =0 in Embodiment 1 of the present invention;

Figure 2(f) is a schematic diagram of position, velocity and acceleration curve planning when q ₀ =-5, q ₁ =5 in Embodiment 1 of the present invention.

Detailed ways

It should be noted that the following detailed description is exemplary and intended to provide further explanation of the present invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

It should be noted that the terminology used here is only for describing specific embodiments, and is not intended to limit exemplary embodiments according to the present invention.

In the case of no conflict, the embodiments and the features in the embodiments of the present invention can be combined with each other.

Embodiment one

This embodiment discloses an improved robot trapezoidal speed curve planning method, including:

Determine the acceleration phase and deceleration phase of the speed curve based on the initial speed, termination speed, and maximum speed in robot motion planning;

In the acceleration phase, the motion of the robot is controlled in a way that the acceleration changes with the acceleration time;

In the deceleration phase, the motion of the robot is controlled in a way that the acceleration changes with the deceleration time.

The trapezoidal speed curve is a speed curve commonly used in robot motion planning, as shown in the trapezoidal curve in Figure 1. The trapezoidal velocity profile calculates the time required for acceleration (T _a ), constant velocity (T _v ) and deceleration (T _d ) based on the initial/end speed, maximum acceleration/deceleration, maximum speed, and start/end displacement , and calculate the expected trajectory according to the displacement, velocity and acceleration formulas. However, there are discontinuous accelerations in the trapezoidal velocity profile, which may cause shock and stress on the mechanical system during the fast feed motion, and even cause damage to the robotic arm or undesirable vibration effects. In order to solve this problem, this embodiment proposes a parabola-based trapezoidal speed curve optimization strategy, as shown by the dotted line in FIG. 1 , this method improves the discontinuity of the trapezoidal speed curve by using the smoothness of the parabola.

The improved trapezoidal speed curve in this embodiment still adopts three sections: an acceleration section, a constant velocity section and a deceleration section, and a parabola is used in the acceleration and deceleration sections to improve the discontinuity.

The expression of the improved trapezoidal velocity curve is:

Among them, a _m is the maximum acceleration, v _m is the maximum speed, τ ₁ , τ ₂ , τ ₃ are the running time of the acceleration phase, the constant speed phase and the deceleration phase respectively, A is the parameter to be obtained, and its size determines the shape of the curve and size.

Assuming that the robot can move at the maximum speed, according to the formula (2) the maximum speed curve expression Available:

Solving the above equations gives:

Assuming that T _a has a solution, it can be obtained from equation (5):

Pick have to:

In this embodiment, the final trajectory expression can be obtained by the above formula (3):

According to the principle of trapezoidal curve symmetry, assuming that the time of the acceleration section and the deceleration section are the same, considering the critical state that is, there is no constant velocity section, that is, T _v = 0, the trajectory can be simplified as:

Will and /> Substitute into the above formula to get:

The available critical speed is:

Among them, v _temp represents the critical speed.

If there is a constant speed stage, then on the basis of formula (10), it can be obtained:

Solve the above equation to get the time T _V of the constant velocity section,

The discriminant formula for whether the system can reach the maximum speed is:

v _lim is the velocity value of the final constant velocity section, that is, v _m =v _lim is used for the calculation of the final displacement, velocity and acceleration (ie formulas (1), (2), (3)).

In this embodiment, the following two situations need to be discussed for the predetermined start position _q0 and end position _q1 :

If q ₁ ≥ _{q 0} , according to the above formulas (1)(2)(3), the corresponding curve trajectory, velocity and acceleration curves can be obtained.

If q ₁ <q ₀ , that is, when the initial position is greater than the end position, the above-mentioned solution process will cause the complex number to find the square root and cause the calculation to fail. The coefficient σ=sign(q ₁ -q ₀ ) is introduced, where sign is a sign function :

Inverts the predetermined start and end position, velocity and acceleration through the coefficients, i.e., Then substitute it into formulas (1), (2), and (3) as known parameters to solve the corresponding trajectory, velocity and acceleration, and then invert the curve again, and finally complete the output of the trajectory.

In this embodiment, the improved trapezoidal velocity curve algorithm is tested, assuming that the maximum velocity v _m =2, the maximum acceleration _am =10, the initial velocity v ₀ =0, and the terminal velocity v ₁ =0, by changing the initial position q ₀ and The end position q ₁ tests the algorithm, ie considers the relative sizes of q ₀ and q ₁ respectively. The experiment sets 6 states, namely:

q ₀ =0, q ₁ >0; q ₀ =0, q ₁ <0;

q ₀ >0, q ₁ =0; q ₀ <0, q ₁ =0;

q ₀ >0, q ₁ <0; q ₀ <0, q ₁ >0;

Based on the above improved algorithm, the position, velocity and acceleration curve planning for the above different situations are shown in Figure 2(a)-Figure 2(f).

According to Figure 2(a)-Figure 2(f), it can be seen that the improved trapezoidal velocity curve algorithm can realize the planning of the motion trajectory, velocity curve and acceleration curve of the manipulator joint in different situations, and shows good performance , to achieve a smooth curve trajectory and a shorter movement time. The results show that the proposed optimization curve algorithm can effectively improve the joint control performance of the manipulator, and has practical application value.

Embodiment two

The purpose of this embodiment is to provide a computing device, which includes a memory, a processor, and a computer program stored in the memory and operable on the processor. The processor implements the steps of the above method when executing the program.

Embodiment three

The purpose of this embodiment is to provide a computer-readable storage medium.

A computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, the steps of the above-mentioned method are executed.

Embodiment four

The purpose of this embodiment is to provide an improved robot trapezoidal speed curve planning system, including:

Determination module: determine the acceleration phase and deceleration phase of the speed curve based on the initial speed, termination speed, and maximum speed in robot motion planning;

Acceleration control module: control the movement of the robot in a way that the acceleration changes with the acceleration time;

Deceleration control module: Control the movement of the robot by changing the acceleration with the deceleration time.

The steps involved in the devices of the above embodiments 2, 3 and 4 correspond to the method embodiment 1, and for specific implementation, please refer to the relevant description of the embodiment 1. The term "computer-readable storage medium" shall be construed to include a single medium or multiple media including one or more sets of instructions; and shall also be construed to include any medium capable of storing, encoding, or carrying A set of instructions to execute and cause the processor to execute any method in the present invention.

Those skilled in the art should understand that each module or each step of the present invention described above can be realized by a general-purpose computer device, optionally, they can be realized by a program code executable by the computing device, thereby, they can be stored in a memory The device is executed by a computing device, or they are made into individual integrated circuit modules, or multiple modules or steps among them are made into a single integrated circuit module for realization. The invention is not limited to any specific combination of hardware and software.

Although the specific implementation of the present invention has been described above in conjunction with the accompanying drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims (10)

1. An improved robot trapezoidal velocity curve planning method, is characterized in that, comprises: Determine the acceleration phase and deceleration phase of the speed curve based on the initial speed, termination speed, and maximum speed in robot motion planning; The acceleration phase controls the motion of the robot in a manner that the acceleration changes based on the acceleration time of the acceleration phase; In the deceleration phase, the movement of the robot is controlled in a way that the deceleration time changes and the acceleration changes during the deceleration phase. 2. a kind of improved robot trapezoidal velocity curve planning method as claimed in claim 1 is characterized in that, determines the coefficient of acceleration stage acceleration time, deceleration stage deceleration time by maximum acceleration, maximum velocity. 3. a kind of improved robot trapezoidal velocity curve planning method as claimed in claim 2, is characterized in that, determines the acceleration by the maximum acceleration of acceleration phase, the acceleration time of acceleration phase, the initial moment of acceleration phase and the coefficient Phase velocity curves. 4. A kind of improved robot trapezoidal speed curve planning method as claimed in claim 2, is characterized in that, the speed curve of deceleration stage is determined by the deceleration time of deceleration stage, maximum speed and said coefficient. 5. a kind of improved robot trapezoidal velocity curve planning method as claimed in claim 1, is characterized in that, also comprises: when the acceleration time of acceleration stage and the deceleration time of deceleration stage are identical and there is no constant speed stage, according to determined The speed curve of the acceleration phase and the speed curve of the deceleration phase obtain the initial position and the end position of the motion track of the robot; determine the critical speed of the robot motion according to the initial position and the end position of the motion track and the maximum acceleration of the acceleration phase; The critical speed and the size of the set maximum speed determine whether the robot moves to the set maximum speed. 6. A kind of improved robot trapezoidal velocity curve planning method as claimed in claim 2, is characterized in that, also comprises: if the initial position of robot motion of being set is greater than the terminal position of setting, then in acceleration phase and deceleration stage, by correcting the initial position, end position, initial velocity and maximum velocity of the acceleration phase of the robot motion based on the sign function of the initial position and the end position, and determining the robot motion based on the corrected parameters and the coefficients track. 7. A kind of improved robot trapezoidal velocity curve planning method as claimed in claim 6, is characterized in that, if the initial position of robot motion of being set is less than the terminal position of setting, then according to the initial position of robot motion of setting , the end position, the initial velocity and the maximum velocity in the acceleration phase and the coefficients determine the trajectory of the robot. 8. An improved robot trapezoidal speed curve planning system, characterized in that it comprises: Determination module: determine the acceleration phase and deceleration phase of the speed curve based on the initial speed, termination speed, and maximum speed in robot motion planning; Acceleration control module: control the movement of the robot in a way that the acceleration changes with the acceleration time; Deceleration control module: Control the movement of the robot by changing the acceleration with the deceleration time. 9. A computer device, characterized in that it comprises: a processor, a memory and a bus, the memory stores machine-readable instructions executable by the processor, and when the computer device is running, the processor and the The memory communicates through the bus, and the machine-readable instructions are executed by the processor to execute an improved robot trapezoidal velocity curve planning method according to any one of claims 1 to 7. 10. A computer-readable storage medium, characterized in that a computer program is stored on the computer-readable storage medium, and when the computer program is run by a processor, a method according to any one of claims 1 to 7 is executed. An improved robot trapezoidal velocity curve planning method.