CN118832596A - Control method of robot - Google Patents

Abstract

The present invention provides a control method for a robot, which comprises: a detection step, detecting the robot's arm length L1, arm length L2, a first motor is arranged at the first joint to drive the arm to rotate around the first joint, a second motor is arranged at the second joint to drive the arm to rotate around the second joint, a screw assembly is connected at the end of the arm, and the current linear acceleration a _total of the screw assembly is detected and calculated; a judgment step, judging the relationship between a total and a _MAX when a _total is maximum, wherein a _MAX is the maximum linear acceleration of the screw end under the condition of considering the life of the screw; a control step, if a _total >a _MAX , then control the speed reduction, and the reduction ratio is Ka; if a _{total≤a MAX} , then maintain the current state. According to the present invention, the situation that the screw is bent or even broken after long-term use can be avoided, and the reliable and stable operation of the robot screw is guaranteed, and its service life is increased.

Description

A robot control method

Technical Field

The present invention relates to the technical field of robots, and in particular to a control method of a robot.

Background Art

The SCARA robot includes the first joint and the second joint of the robot. When the first joint and the second joint move, the different postures, speeds and accelerations of the joints in the motion process planning will bring different load pressures to the motors of the first joint and the second joint. For the acceleration of the first and second joints, it is usually necessary to consider the torque that the motor can output and the overload situation, or the maximum torque that the reducer can withstand. The screw at the end of the scara will be subjected to a large horizontal force when rotating horizontally. When the first and second joints of the robot move with a large acceleration, a large bending moment and shear force will be generated on the screw. When it exceeds its bearing limit, the service life of the screw will be reduced. In severe cases, the screw will bend or even break.

Patent application number 202310582214.3 (patent number CN116572226A) discloses a method of using a retractable energy-absorbing buffer device on the structure to ensure the safety of the screw assembly structure. Patent application number 202223256026.1 (patent number CN219006064U) discloses a method of using multiple sets of electromagnetic buffer components to adjust the clearance and compression strength by using the attraction and mutual repulsion of magnetic poles to protect the screw. Both of the above are patented designs that absorb energy or reduce compression strength through structural parts.

However, they all have the problem that the SCARA robot has a large movement acceleration when moving in the horizontal direction, which causes the lead screw to bear an excessive radial load and thus reduces the life of the lead screw.

Since the SCARA robot in the prior art has a large motion acceleration when moving in the horizontal direction, which causes the screw rod to bear too large radial load and thus reduces the life of the screw rod, the present invention studies and designs a control method for the robot.

Summary of the invention

Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that the SCARA robot has a large movement acceleration when moving in the horizontal direction, which causes the screw rod to bear excessive radial load and reduces the life of the screw rod, thereby providing a control method for the robot.

In order to solve the above problems, the present invention provides a robot control method, which comprises:

A detection step, detecting the length L1 of the robot's upper arm and the length L2 of its lower arm, providing a first motor at the first joint to drive the upper arm to rotate around the first joint, providing a second motor at the second joint to drive the lower arm to rotate around the second joint, connecting a lead screw assembly at the end of the lower arm, and detecting and calculating a _total current linear acceleration of the lead screw assembly;

A determination step, determining the relationship between a _total and a _MAX when a is at a maximum, wherein a _MAX is the maximum linear acceleration of the end of the screw rod in consideration of the life of the screw rod;

Control steps: if a _total > a _MAX , control the speed to decrease, and the decrease ratio is Ka; if a _total ≤ _{a MAX} , maintain the current state.

In some embodiments,

The control step controls And control A1'= _Ka ·A1, A2'= _Ka ·A2, wherein A1 is the current angular acceleration of the first joint, A2 is the current angular acceleration of the second joint, A1' is the target angular acceleration of the first joint, and A2' is the target angular acceleration of the second joint.

In some embodiments,

In the control step, when the first joint moves alone, the current linear acceleration of the screw assembly is a _L = L·A ₁ , and when the second joint moves alone, the current linear acceleration of the screw assembly is a ₂ = L ₂ ·A ₂ . In the plane where the forearm and the upper arm are located, the linear acceleration of the screw assembly is The direction of + is perpendicular to the length extension direction of the forearm, and L is the length of the other side of the triangle formed by the forearm and the upper arm. The direction of the other side is perpendicular to the extension direction of the other side.

In some embodiments,

The linear acceleration a of the screw assembly _is calculated by the following formula:

In some embodiments,

In the control step, when the first joint moves alone, the target linear acceleration of the screw assembly is a _L '＝L·A ₁ ', when the second joint moves alone, the current linear acceleration of the screw assembly is a ₂ '＝L ₂ ·A ₂ ', and the target linear acceleration of the screw assembly is a _total ', so a _L '＝K _a ·a _L , a ₂ '＝K _a ·a ₂ , a _total '＝K _a ·a _total ＝a _MAX .

In some embodiments,

In the plane where the lower arm and the upper arm are located, an acute angle is formed between the lower arm and the upper arm. When a is _always the maximum, the degree of the acute angle at this position is calculated to be θ ₂ .

In some embodiments,

The angle between the small arm and the large arm is an obtuse angle, and θ ₂ is sandwiched between the extension line of the large arm and the small arm.

In some embodiments,

The control step re-plans the joint motion and controls the time scaling to ensure that the angle of the maximum acceleration at the moment after a _total is scaled is still θ ₂ , that is, the position where the maximum acceleration occurs is still at the position of θ ₂ , ensuring that there will be no acceleration greater than a _total at other angles, preventing the maximum load of the Z-axis screw rod from being exceeded, and preventing the end acceleration from exceeding a _MAX .

In some embodiments,

If the motion planning shows that the acceleration needs to be reduced by a factor _of Ka, then the time If the joint acceleration is scaled by times, A2'= _Ka ·A2, A1'= _Ka ·A1, and after the acceleration is adjusted by times _Ka in the form of time scaling, the maximum acceleration of the entire plan is _atotal ' and still corresponds to the angle θ ₂ .

In some embodiments,

The interpolation of the original motion plan is 2ms, that is, an interpolation point is sent every 2ms, that is, the position information is sent every 2ms; the time is scaled by 0.5 times, and the interpolation point with the original interval of 1ms is sent every 2ms. Then, the speed in the entire plan becomes 0.5 times the original, and the acceleration becomes 0.5*0.5=0.25 times the original.

The robot control method provided by the present invention has the following beneficial effects:

The present invention ensures the life of the screw rod during the use of the robot by linking the acceleration of the first and second joints of the robot (preferably a SCARA robot) during the motion planning process with the maximum horizontal motion line acceleration that the screw rod can withstand, thereby ensuring that the radial load received by the screw rod during the final motion process is less than its bearing limit, avoiding the bending or even breaking of the screw rod after long-term use, ensuring the reliable and stable operation of the robot screw rod, and improving its service life. The present invention also completes the re-planning of the joints through the time-scaling multiplier adjustment method, which can ensure that the maximum acceleration after planning is a _total 'still corresponds to the angle θ ₂ , ensuring that there will be no acceleration greater than a _total 'at other angles, preventing the maximum load of the Z-axis screw rod from being exceeded, and preventing the terminal acceleration from exceeding a _MAX , further ensuring the reliable and stable operation of the robot screw rod, and further improving its service life.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 is a side structural diagram of a SCARA robot of the present invention;

2 is a top view of the SCARA robot of the present invention (the upper figure shows that the upper arm is perpendicular to the lower arm, and the lower figure shows that the upper arm is parallel to the lower arm);

3 is a schematic diagram of a force (torque) analysis of a SCARA robot from a top view of the present invention;

FIG. 4 is a flow chart of a control method of a SCARA robot according to the present invention.

The reference numerals are as follows:

1. First joint; 2. Second joint; 3. Screw assembly; 4. Upper arm; 5. Lower arm.

DETAILED DESCRIPTION

The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and/or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and/or combinations thereof.

Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values do not limit the scope of the present invention. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the devices or elements referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention. The directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

As shown in FIGS. 1-4 , the present invention provides a robot control method, which includes:

A detection step, detecting a length L1 of the robot's upper arm 4 and a length L2 of the lower arm 5, setting a first motor at the first joint 1 to drive the upper arm 4 to rotate around the first joint 1, setting a second motor at the second joint 2 to drive the lower arm 5 to rotate around the second joint 2, connecting a lead screw assembly 3 at the end of the lower arm 5, detecting and calculating a _total current linear acceleration of the lead screw assembly 3;

A determination step, determining the relationship between a _total and a _MAX when a is at a maximum, wherein a _MAX is the maximum linear acceleration of the screw assembly 3 taking into account the life of the screw;

Control steps: if a _total > a _MAX , control the speed to decrease, and the decrease ratio is Ka; if a _total ≤ _{a MAX} , maintain the current state.

The present invention ensures that the radial load received by the screw rod during the final movement is less than its bearing limit by linking the acceleration of the first and second joints of the robot (preferably a SCARA robot) during the motion planning process with the maximum horizontal motion line acceleration that the screw rod can withstand, thereby ensuring the life of the screw rod during the use of the robot, avoiding the bending or even breakage of the screw rod after long-term use, ensuring the reliable and stable operation of the robot screw rod and increasing its service life.

The present invention is a first and second joint acceleration constraint method based on the life of the SCARA robot screw rod. When performing motion planning for the first and second joints, the acceleration of the first and second joints is proportionally reduced based on the structural strength of the screw rod and taking into account the extension length of J3 to ensure the service life of the screw rod.

The present invention proposes a method for ensuring the life of the screw rod by constraining the acceleration of the first joint and the second joint of the SCARA robot. Different types of screw rods will have different bearing upper limits in the radial direction under different assembly conditions. At the beginning of product design, there will be product life requirements. After the structural design of the screw rod part is completed, there will be certain restrictions on the radial force received by the screw rod during the movement. The radial force of the screw rod during the movement mainly comes from the inertial force generated during the movement of the first joint and the second joint of the SCARA robot. According to the bearing limit of the radial load (inertial force) of the screw rod, it can be known that the maximum acceleration that it can withstand when moving in the horizontal direction. In the process of planning the movement of the first and second joints, it is ensured that the maximum linear acceleration during the movement of the screw rod does not exceed its bearing limit, so that its service life can be guaranteed.

In some embodiments,

The control step controls And control A1'= _Ka ·A1, A2'= _Ka ·A2, wherein A1 is the current angular acceleration of the first joint 1, A2 is the current angular acceleration of the second joint 2, A1' is the target angular acceleration of the first joint 1, and A2' is the target angular acceleration of the second joint 2.

This is a further method of determining _{Ka according} to the present invention, by That is, the maximum linear acceleration of the screw assembly can be controlled at or below a _MAX , thereby effectively ensuring that the maximum linear acceleration of the robot and the screw assembly will not exceed a _MAX during operation. At the same time, the angular accelerations of the motors at the first joint and the second joint are multiplied by the coefficient _Ka , respectively, to effectively achieve control, and reduce the angular accelerations of the motors of the two joints (the angular accelerations may correspond to the motor speeds) by multiples, that is, control the speeds of the two motors to decrease, and obtain two target angular accelerations, thereby achieving control of the maximum linear acceleration of the screw assembly not exceeding a _MAX , thereby ensuring reliable and effective operation of the screw assembly and increasing its service life.

In some embodiments,

In the control step, when the first joint 1 moves alone, the current linear acceleration of the screw assembly 3 is a _L = L·A ₁ , and when the second joint 2 moves alone, the current linear acceleration of the screw assembly 3 is a ₂ = L ₂ ·A ₂ . In the plane where the small arm 5 and the large arm 4 are located, the current linear acceleration of the screw assembly 3 is The direction of + is perpendicular to the length extension direction of the small arm 5, and L is the length of the other side of the triangle formed by the small arm 5 and the large arm 4. The direction of the other side is perpendicular to the extension direction of the other side.

This is the correspondence between the linear acceleration and the angular acceleration at the two joints of the present invention. According to FIG3 , when the screw assembly is driven by the first joint alone, its linear acceleration is the angular acceleration of the first joint multiplied by the force arm between the first joint and the screw assembly. However, the force arm at the position of the screw assembly relative to the first joint should be L, where L is the length of the other side of the triangle formed by the forearm and the upper arm. Therefore, a _L = L·A ₁ . When the screw assembly is driven by the second joint alone, its linear acceleration is the angular acceleration of the second joint multiplied by the force arm between the second joint and the screw assembly. Therefore, a ₂ = L ₂ ·A ₂ . The direction of + is perpendicular to the length extension direction of the forearm 5, The direction is perpendicular to the extension direction of the other side, and the rotational force of the driving screw assembly of the two is perpendicular to the small arm and the other side respectively.

In some embodiments,

The linear acceleration a of the screw assembly 3 _is calculated by the following formula:

The present invention also It can effectively calculate the current linear acceleration of the screw assembly, and then compare a _total with a _MAX to determine whether it exceeds a _MAX , and control whether to reduce the speed, to ensure that the operation process does not exceed the strength range of the screw assembly, improve reliability, and increase its service life.

In some embodiments,

In the control step, when the first joint 1 moves alone, the target linear acceleration of the screw assembly 3 is _a'L =L· _A1 ', when the second joint 2 moves alone, the current linear acceleration of the screw assembly 3 is _a'2 = _L2 · _A2 ', and the target linear acceleration of the screw assembly 3 is _atotal ', so _aL '= _Ka · _aL , _a2 '= _Ka · _a2 , _atotal '=Ka _{· atotal} = _aMAX .

The present invention can further calculate the target linear acceleration through the target angular acceleration, and obtain the relationship between the target linear acceleration and the current linear acceleration, as well as the relationship between the screw target bus acceleration and the current target linear acceleration, thereby meeting the robot's requirements for the life of the screw strength during operation, ensuring reliable and stable operation and increasing the service life.

The present invention is applied to the motion control system of a SCARA robot, and acts to reduce the maximum acceleration of a first joint and a second joint in motion planning, thereby ensuring that the radial acceleration to which a screw rod is subjected is within its tolerance range during the motion of the robot, and that the service life of the screw rod is not reduced due to an excessive radial load during use.

According to the screw model and the life of the screw, there is a limit a _MAX on the maximum linear acceleration of the screw end. If the original motion planning joint angular acceleration A1, A2, the corresponding linear acceleration a _always exceeds a _MAX , the acceleration of the first joint and the second joint will be reduced proportionally. The angular acceleration of the first joint after constraint is A1'= _Ka ·A1, and the angular acceleration of the second joint after constraint is A2'= _Ka ·A2. The corresponding linear acceleration of the end lead screw when the first joint moves alone is _aL '= _Ka · _aL , and the linear acceleration of the end lead screw when the second joint moves alone is _a2 '= _Ka · _a2 . Vector synthesis yields the final linear acceleration of the end lead screw _atotal '=Ka _{· atotal} = _aMAX . By reducing the acceleration by the Ka coefficient, it is possible to ensure that the linear acceleration of the lead screw in the horizontal direction is within the maximum linear acceleration it can withstand. Under this condition, the second motion planning is carried out, and its radial load will not exceed the bearing limit, thereby ensuring its service life.

In some embodiments,

In the plane where the small arm 5 and the large arm 4 are located, an acute angle is formed between the small arm 5 and the large arm 4. When a is _always the maximum, the degree of the acute angle at this position is calculated to be θ ₂ .

The present invention can combine the acute angle _θ2 in the vector diagram + and Calculated And obtain the preferred angle position between the upper arm and the lower arm for maximum a _total .

After the robot performs motion planning, when the planned position moves to any position as shown in Figure 3, the forearm and the extended line of the upper arm form an angle _θ2 . The distance L between the end of the lead screw and the rotation center of the first joint can be obtained through the upper arm length L1 and the forearm length L2. The linear acceleration _aL = L· _A1 of the terminal lead screw when the first joint moves alone and the linear acceleration _a2 = _L2 · _A2 of the terminal lead screw when the second joint moves alone can be obtained through the planned first joint angular acceleration A1 and the second joint angular acceleration A2. The linear acceleration generated by the two joint movements is vector-synthesized to obtain the final linear acceleration _atotal of the terminal lead screw, that is, the linear acceleration

In some embodiments,

The angle between the small arm 5 and the large arm 4 is an obtuse angle, and the acute angle θ ₂ is formed between the extension line of the large arm 4 and the small arm 5 .

This is a further preferred form of the robot control method of the present invention. As shown in FIG3 , an obtuse angle is formed between the upper arm and the lower arm, and the acute angle is the supplementary angle of the obtuse angle, that is, the angle formed between the extended line of the upper arm and the lower arm is the acute angle θ ₂ .

In some embodiments,

The control step re-plans the joint motion and controls the time scaling to ensure that the angle of the maximum acceleration at the moment after a _total is scaled is still θ ₂ , that is, the position where the maximum acceleration occurs is still at the position of θ ₂ , ensuring that an acceleration greater than a _total 'will not appear at other angles, preventing the maximum load of the Z-axis screw rod from being exceeded, and preventing the end acceleration from exceeding a _MAX .

The present invention also completes the re-planning of the joints through the time scaling multiplier adjustment method, which can ensure that the planned maximum acceleration is a _total 'still corresponds to the angle θ ₂ , and ensure that an acceleration greater than a _total 'will not appear at other angles, thereby preventing the maximum load of the Z-axis lead screw from being exceeded and preventing the terminal acceleration from exceeding a _MAX , further ensuring the reliable and stable operation of the robot lead screw and further improving its service life.

In some embodiments,

If the motion planning shows that the acceleration needs to be reduced by a factor _of Ka, then the time If the joint acceleration is scaled by times, A2'= _Ka ·A2, A1'= _Ka ·A1, and after the acceleration is adjusted by times _Ka in the form of time scaling, the maximum acceleration of the entire plan is _atotal ' and still corresponds to the angle θ ₂ .

In some embodiments,

The interpolation of the original motion plan is 2ms, that is, the interpolation point (absolute joint position) is sent every 2ms, that is, the position information is sent every 2ms (angular acceleration information can be obtained through the position information); the time is scaled by 0.5 times, and the interpolation point with the original interval of 1ms is sent every 2ms. Then, the speed in the entire plan becomes 0.5 times the original speed, and the acceleration becomes 0.5*0.5=0.25 times the original speed.

a _{total is} the maximum acceleration in the entire motion planning process. In order to ensure that after the acceleration of the two joints is reduced by the Ka _coefficient , the maximum acceleration of the entire plan is a _total ' and still corresponds to the angle θ ₂ , the joint re-planning can be completed by adjusting the time scaling ratio. For example: the interpolation of the original motion plan is 2ms, that is, an interpolation point (absolute joint position) is sent every 2ms; the time is scaled by 0.5 times, and the interpolation point with the original interval of 1ms is sent every 2ms. Then, the speed in the entire planning becomes 0.5 times the original, and the acceleration becomes 0.5*0.5=0.25 times the original. If it is found that the acceleration needs to be reduced by _Ka after the motion planning, the time is scaled by 0.5 times. The joint acceleration is A2'= _Ka ·A2, A1'= _Ka ·A1. After the acceleration is adjusted by Ka _times in the form of time scaling, the maximum acceleration of the entire plan is _atotal ' and still corresponds to the angle _θ2 .

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present invention. These improvements and variations should also be regarded as the protection scope of the present invention.

Claims (10)

1. A control method of a robot is characterized in that: comprising the following steps:

The method comprises the steps of detecting the length L1 of a large arm (4) and the length L2 of a small arm (5) of a robot, arranging a first motor at a first joint (1) to drive the large arm (4) to rotate around the first joint (1), arranging a second motor at a second joint (2) to drive the small arm (5) to rotate around the second joint (2), connecting a screw rod assembly (3) at the tail end of the small arm (5), and detecting and calculating the current linear acceleration a _{Total (S)} of the screw rod assembly (3);

A judging step of judging the relationship between a _{Total (S)} and a _MAX when a _{Total (S)} is maximum, wherein a _MAX is the maximum linear acceleration of the screw assembly (3) under the condition of considering the service life of the screw;

a control step, if a _{Total (S)} ＞a_MAX, controlling the speed reduction, wherein the reduction ratio is Ka; if a _{Total (S)} ≤a_MAX, the current state is maintained.

2. The method of controlling a robot according to claim 1, wherein:

The control step controls And controlling A1' =k _a·A1,A2'＝K_a ·a2, wherein A1 is the current angular acceleration of the first joint (1), A2 is the current angular acceleration of the second joint (2), A1' is the target angular acceleration of the first joint (1), and A2' is the target angular acceleration of the second joint (2).

3. The control method of a robot according to claim 2, characterized in that:

the control step comprises the steps that the current linear acceleration a _L＝L·A₁ of the screw rod assembly (3) when the first joint (1) moves independently, the current linear acceleration a ₂＝L₂·A₂ of the screw rod assembly (3) when the second joint (2) moves independently, and the screw rod assembly (3) is arranged in the plane where the small arm (5) and the big arm (4) are arranged together The direction of +is perpendicular to the length extending direction of the small arm (5), L is the length of the other side of the triangle surrounded by the small arm (5) and the large arm (4),Is perpendicular to the direction of extension of the other edge.

4. A control method of a robot according to claim 3, characterized in that:

the linear acceleration a _{Total (S)} of the screw rod assembly (3) is calculated by the following formula:

5. the method of controlling a robot according to claim 4, wherein:

The control step comprises the target linear acceleration a _L'＝L·A₁ 'of the screw rod assembly (3) when the first joint (1) moves independently, the current linear acceleration a' ₂＝L₂·A₂ 'of the screw rod assembly (3) when the second joint (2) moves independently, and the target linear acceleration of the screw rod assembly (3) is a _{Total (S)} ', so that the control step comprises the following steps of a_L'＝K_a·a_L,a₂'＝K_a·a₂,a _{Total (S)} '＝K_a·a _{Total (S)} ＝a_MAX.

6. The method of controlling a robot according to claim 5, wherein:

In a plane where the small arm (5) and the large arm (4) are located together, an acute angle is formed between the small arm (5) and the large arm (4), and when a _{Total (S)} is the maximum, the degree of the acute angle at the position is calculated to be theta ₂.

7. The method of controlling a robot according to claim 6, wherein:

The angle between the small arm (5) and the large arm (4) is an obtuse angle, and the theta ₂ is clamped between the extension line of the large arm (4) and the small arm (5).

8. The method of controlling a robot according to claim 6, wherein:

And the control step is to carry out joint motion planning again, control time scaling, ensure that the angle of the maximum acceleration moment after scaling a _{Total (S)} is still theta ₂, namely the position where the maximum acceleration occurs is still positioned at the position of theta ₂, ensure that the acceleration larger than a _{Total (S)} ' does not occur at other angles, prevent the maximum bearing load from exceeding the Z-axis screw rod, and prevent the terminal acceleration from exceeding a _MAX.

9. The method of controlling a robot according to claim 8, wherein:

if the motion planning is carried out to obtain that the K _a times of the acceleration is needed to be reduced, the time is carried out The joint acceleration A2 '=k _a·A2,A1'＝K_a ·a1, and after K _a times adjustment of the acceleration by time scaling, the maximum acceleration of the whole plan is a _{Total (S)} ' and still corresponds to the angle θ ₂.

10. The control method of a robot according to claim 9, characterized in that:

Interpolation of the original motion planning is 2ms, namely interpolation points are sent once every 2ms, namely position information is sent once every 2 ms; and scaling the time by 0.5 times, and transmitting interpolation points with the original interval of 1ms every 2ms, wherein the speed in the whole section of planning becomes 0.5 times as before, and the acceleration becomes 0.5 times as before and 0.5=0.25 times as before.