Controllable rapid folding machine arm and control method and system thereof

Abstract

The invention relates to a controllable rapid folding machine arm and a control method and system thereof, belongs to the technical field of folding machine arms, and solves the problems that in the prior art, when the machine arm is unfolded, a machine body is poor in stability due to impact force, and an existing multi-steering-engine system is too large in weight, high in machining cost and poor in reliability. The control method comprises the steps that time-rotation angle discrete data of a steering engine in the arm unfolding process are obtained according to a steepest curve; fitting the time-rotation angle discrete data through a selected fitting function to obtain a time-rotation angle fitting curve of the steering engine; and according to the time-rotation angle fitting curve of the steering engine, the rotation angles of the steering engine at different moments in the arm unfolding process are controlled, so that the speed of the arm is zero when the arm is unfolded to the maximum rotation angle. The arm can be rapidly and stably unfolded within millisecond time, and reliable technical support is provided for stable hovering of devices such as an unmanned aerial vehicle and the like in the air.

Description

Technical Field

[0001] The present invention relates to the technical field of folding machine arms, and in particular to a controllable fast folding machine arm and a control method and system thereof. Background Art

[0002] Drone technology is increasingly being used in all areas of military and life, including aerial photography, agriculture, logistics, scientific research, battlefield reconnaissance, etc. However, existing drone designs are insufficient in terms of portability and flexibility, especially for applications that require rapid deployment and unstable launch conditions. To address this problem, multi-rotor folding drones have emerged. Multi-rotor folding drones are an innovative drone design that features foldable arms that can fold the wings and rotors when not in use, greatly reducing the size and making the drone more convenient to carry and store, and can be easily put into a backpack or small package. In addition, multi-rotor folding drones can unfold their wings and rotors during takeoff and landing, providing greater lift and stability, thereby having higher maneuverability during flight. It can take off and land in a small space and can cope with different flight mission requirements, such as reconnaissance, search and rescue, etc.

[0003] At present, part of the automatic deployment mechanism of multi-rotor folding drones adopts a hinged folding method, which adopts a self-locking design of torsion springs, rotating shafts and multi-links. The elastic force of the spring pushes the arm to rotate axially outward, and then fixes it through a latching mechanism to achieve the deployment of the arm. Existing hinged folding methods are mostly one-time folding, that is, they need to be manually reset, are difficult to recycle and reuse, and have poor controllability and stability.

[0004] In addition, there are also methods in the prior art that use electric folding mechanisms to achieve automatic folding of the arms, such as the electric folding mechanism used in transformable drones. This folding mechanism controls the rotation of the arms through multiple servos, which can change the appearance of the drone. However, the existing electric folding mechanism uses a complex multi-servo system, which leads to excessive weight, high processing costs and poor reliability. At the same time, in the prior art, when controlling the unfolding of the arms, a PWM signal is directly given to the servo to rotate to 90° (maximum rotation angle). At this time, the servo will rotate at a uniform speed at the maximum speed, and its speed change curve is as follows: Figure 1 At 0° (0s) and when the maximum rotation angle is 90° (0.6s), the angular velocity of the servo will change suddenly, especially when the arm is fully extended at 0.6s, the arm will stop after impact, and the impact force will cause the body to experience speed and acceleration disturbances, resulting in greater shaking of the body and poor stability. Summary of the invention

[0005] In view of the above analysis, an embodiment of the present invention aims to provide a controllable fast-folding arm and a control method and system thereof, so as to solve the problem of poor stability of the body due to impact force when the arm is deployed in the existing arm deployment control method and the problem of excessive weight, high processing cost and poor reliability caused by the existing multi-servo system.

[0006] In a first aspect, an embodiment of the present invention provides a control method for a controllable fast folding machine arm, wherein the controllable fast folding machine arm comprises: a machine arm and a steering gear, wherein the steering gear drives the machine arm to unfold to a preset angle by rotating, and the control method comprises:

[0007] Obtaining discrete data of the time-rotation angle of the servo during the arm deployment process according to the fastest curve;

[0008] Fitting the time-rotation angle discrete data by a selected fitting function to obtain a time-rotation angle fitting curve of the steering gear;

[0009] The rotation angle of the servo at different moments during the arm deployment process is controlled according to the time-rotation angle fitting curve of the servo, so that the speed of the arm is zero when the arm is deployed to the maximum rotation angle.

[0010] Based on the further improvement of the above control method, the equation of the fastest curve is:

[0011] x = R(θ-sinθ);

[0012] y = R(1-cosθ);

[0013] Where x is the x-axis coordinate, y is the y-axis coordinate, R is the radius of the cycloid circle, and θ is the rotation angle of the cycloid.

[0014] Based on the further improvement of the above control method, the step of obtaining the time-rotation angle discrete data of the servo during the arm deployment process according to the fastest curve includes:

[0015] Get the x-axis discrete coordinates and y-axis discrete coordinates [(x1,y1)…(x n ,y n )];

[0016] The x-axis discrete coordinates are mapped to the rotation time of the servo, and the y-axis discrete coordinates are mapped to the rotation angle of the servo, so as to obtain the time-rotation angle discrete data of the servo during the arm deployment process [(0,0)…(T,ω max )], T is the maximum rotation time of the servo, ω max is the maximum rotation angle of the servo.

[0017] Based on the further improvement of the above control method, the fitting function includes an exponential decay function, and the formula of the exponential decay function is:

[0018] ω=a-be -kt ;

[0019] Where ω is the rotation angle of the servo, t is the time, and a, b, and k are the parameters to be fitted.

[0020] Based on the further improvement of the above control method, the controlling the rotation angle of the servo at different times during the arm deployment process according to the time-rotation angle fitting curve of the servo includes:

[0021] According to the time-rotation angle fitting curve of the servo, the rotation angles at different times during the arm deployment process are obtained, and converted into corresponding PWM signals;

[0022] When the machine arm is unfolded, a PWM signal is sent to the servo at a preset frequency to control the rotation angle of the servo.

[0023] Based on the further improvement of the above control method, the control method further includes:

[0024] The sent PWM signal is counted, and if the count value reaches the set threshold, the sending of the PWM signal is stopped.

[0025] In a second aspect, an embodiment of the present invention provides a control system for a controllable fast folding machine arm, wherein the controllable fast folding machine arm comprises: a machine arm and a steering gear, wherein the steering gear drives the machine arm to unfold to a preset angle by rotating,

[0026] The control system comprises:

[0027] A discrete module, for obtaining discrete data of time-rotation angle of the servo during the arm deployment process according to the fastest curve;

[0028] A fitting module, fitting the time-rotation angle discrete data by a selected fitting function to obtain a time-rotation angle fitting curve of the servo;

[0029] The control module controls the rotation angle of the servo at different times during the arm deployment process according to the time-rotation angle fitting curve of the servo, so that the speed of the arm is zero when the arm is deployed to the maximum rotation angle.

[0030] Based on the further improvement of the above control system, the control module includes:

[0031] A signal conversion module, used to obtain the rotation angles at different times during the deployment of the arm according to the time-rotation angle fitting curve of the servo, and convert them into corresponding PWM signals;

[0032] The signal sending module is used to send a PWM signal to the steering gear at a preset frequency when receiving the arm extension signal, so as to control the rotation angle of the steering gear.

[0033] Based on the further improvement of the above control system, the control system and the steering gear are powered by a power supply.

[0034] A first voltage stabilizer is arranged between the power supply and the control system, and a second voltage stabilizer is arranged between the power supply and the steering gear.

[0035] In a third aspect, an embodiment of the present invention provides a controllable fast folding machine arm, wherein the controllable fast folding machine arm uses the control method and / or the control system as described above to control its arm extension process, and the controllable fast folding machine arm comprises: a machine arm, a steering gear and a folding mechanism, and when the steering gear rotates, the machine arm is driven to unfold to a preset angle through the folding mechanism.

[0036] The folding mechanism comprises: a steering gear bracket, an arm connecting rod, a U-shaped mounting frame, a connecting rod, and a steering gear arm, wherein the steering gear is fixedly mounted on the steering gear bracket, the steering gear arm is arranged on the steering gear, the U-shaped mounting frame is fixedly connected to the steering gear bracket, the arm connecting rod is rotatably arranged on the U-shaped mounting frame, the arm connecting rod is fixedly connected to the arm, and two ends of the connecting rod are respectively hinged to the steering gear arm and the arm connecting rod.

[0037] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0038] 1. The control method and control system of the present invention have high reliability and control accuracy. The relationship curve between the rotation angle and time of the servo during the arm deployment process is optimized based on the fastest curve (also called cycloid), which can meet the requirement that the speed is zero when the arm is deployed to the maximum rotation angle (deployment is completed), thereby avoiding or reducing the impact when the deployment is completed, and the rotation angle of the servo at different times during the arm deployment process is controlled according to the fastest curve, so that the change trend of the rotation angle of the servo over time is smooth, which is conducive to fast and stable control of the arm deployment process, and can achieve fast and stable arm deployment within milliseconds, providing reliable technical support for stable hovering in the air of devices such as drones.

[0039] 2. Considering the existence of an intermediate variable θ in the fastest curve equation, it is inconvenient to directly embed the equation into the control system. The present invention provides a control method based on time discretization, in which the rotation angle data of the servo is discretized according to time and then fitted by a fitting function for use.

[0040] 3. In the present invention, the structure of the folding mechanism is improved, the structure is simple, and it can drive the machine arm to fold more than 90 degrees.

[0041] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0043] Figure 1 The figure is a curve diagram of the rotation angle and angular velocity of the steering gear during the arm extension process in the prior art;

[0044] Figure 2 A schematic flow chart of a control method according to an embodiment of the present invention;

[0045] Figure 3 Schematic diagram of the principle of the fastest curve of an embodiment of the present invention;

[0046] Figure 4 is a schematic diagram of x-axis discrete coordinates and y-axis discrete coordinates according to an embodiment of the present invention;

[0047] Figure 5 is the coordinate point (x1, y1)…(x n ,y n )

[0048] Figure 6 A schematic diagram of discrete points of time-rotation angle discrete data of a servo obtained after mapping in an embodiment of the present invention;

[0049] Figure 7 A schematic diagram of a time-rotation angle fitting curve of a servo according to an embodiment of the present invention;

[0050] Figure 8 Schematic diagram of a counting control process according to an embodiment of the present invention;

[0051] Fig. 9 This is a schematic diagram of the connection structure of a controllable fast folding machine arm, a control system and a power supply according to an embodiment of the present invention;

[0052] Fig.10 is a schematic diagram of a folding mechanism according to an embodiment of the present invention;

[0053] Fig.11Schematic diagram of a drone according to an embodiment of the present invention.

[0054] Reference numerals:

[0055] 1. Servo bracket; 2. Arm connecting rod; 3. U-shaped mounting bracket; 4. Connecting rod;

[0056] 5. Servo arm; 6. Servo. DETAILED DESCRIPTION

[0057] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of this application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0058] A specific embodiment of the present invention discloses a control method for controlling a controllable fast folding machine arm. The controllable fast folding machine arm comprises: a machine arm and a steering gear 6, wherein the steering gear 6 drives the machine arm to unfold to a preset angle by rotation. The steering gear 6 is a core component of the UAV, and the control system controls the rotation of the steering gear 6 to realize the folding and unfolding of the machine arm. The steering gear 6 adopts a high-performance model with high torque and fast response characteristics, ensuring that the mechanism can accurately and stably complete the folding and unfolding actions under different working conditions.

[0059] like Figure 2 As shown, the control method of the embodiment of the present invention includes:

[0060] Step 1, obtaining the time-rotation angle discrete data of the servo 6 during the arm deployment process according to the fastest curve;

[0061] Step 2, fitting the time-rotation angle discrete data by using a selected fitting function to obtain a time-rotation angle fitting curve of the steering gear 6;

[0062] Step 3, controlling the rotation angle of the servo 6 at different times during the arm deployment process according to the time-rotation angle fitting curve of the servo 6, so that the speed of the arm is zero when the arm is deployed to the maximum rotation angle.

[0063] Compared with the prior art, the control method of the embodiment of the present invention has higher reliability and control accuracy, wherein, based on the fastest curve (also called cycloid), the relationship curve between the rotation angle and time of the servo 6 in the arm deployment process is optimized and set, which can meet the requirement that the speed is zero when the arm is deployed to the maximum rotation angle (deployment is completed), thereby avoiding or reducing the impact generated when the deployment is completed, and the rotation angle of the servo 6 at different times in the arm deployment process is controlled according to the fastest curve, so that the change trend of the rotation angle of the servo 6 with time is smooth, which is conducive to fast and stable control of the arm deployment process, and can achieve fast and stable arm deployment within milliseconds, providing reliable technical support for the stable hovering of devices such as drones in the air.

[0064] At the same time, considering the existence of an intermediate variable θ in the fastest curve equation, it is inconvenient to directly embed the equation into the control system. The present invention provides a control method based on time discretization, in which the rotation angle data of the servo 6 is discretized according to time and then fitted by a fitting function for use.

[0065] Wherein, the equation of the fastest curve is:

[0066] x = R(θ-sinθ);

[0067] y = R(1-cosθ);

[0068] In the formula, x is the x-axis coordinate, y is the y-axis coordinate, R is the radius of the cycloid circle, and θ is the rotation angle of the cycloid. Figure 3 as shown in .

[0069] Step 1, obtaining the time-rotation angle discrete data of the servo 6 during the arm deployment process according to the fastest curve, includes:

[0070] Step 11, obtain the x-axis discrete coordinates and y-axis discrete coordinates [(x1,y1)…(x n ,y n )];

[0071] Step 12, mapping the x-axis discrete coordinates to the rotation time of the steering gear 6, and mapping the y-axis discrete coordinates to the rotation angle of the steering gear 6, so as to obtain the time-rotation angle discrete data [(0,0)…(T,ω max )].

[0072] Wherein, T is the maximum rotation time of the steering gear 6, that is, the arm extension time, which can be specifically set to 0.6s; ω max It is the maximum rotation angle of the steering gear 6, i.e. the deflection angle when the arm is deployed, which can be specifically set to 90 °. In addition, when the arm is closed, its deflection angle is 0 °, and the rotation angle of the steering gear 6 is 0 °.

[0073] Specifically, in step 11, the x-axis discrete coordinates and the y-axis discrete coordinates are calculated using the rotation angle of the cycloid, such as Figure 4 As shown in n ,y n ),like Figure 5 In step 12, the discrete points of the time-rotation angle discrete data of the servo 6 obtained after mapping are as follows: Figure 6 as shown in .

[0074] In one embodiment, in step 2, the fitting function adopts an exponential decay function, and the formula of the exponential decay function is:

[0075] ω=a-be -kt ;

[0076] Wherein, ω is the rotation angle of the steering gear 6, t is the time, and a, b, and k are the parameters to be fitted.

[0077] Step 2, fitting the time-rotation angle discrete data by exponential decay function, and obtaining the time-rotation angle fitting curve of the steering gear 6, such as Figure 7 as shown in .

[0078] In addition, in the embodiment of the present invention, the fitting function may also adopt other functions such as a polynomial function and a power function.

[0079] In one embodiment, step 3, controlling the rotation angle of the steering gear 6 at different times during the arm deployment process according to the time-rotation angle fitting curve of the steering gear 6, includes:

[0080] According to the time-rotation angle fitting curve of the steering gear 6, the rotation angles at different times during the arm deployment process are obtained and converted into corresponding PWM signals;

[0081] When the machine arm is unfolded, a PWM signal is sent to the servo 6 at a preset frequency to control the rotation angle of the servo 6 .

[0082] In the embodiment of the present invention, a PWM signal corresponding to the moment is generated according to the rotation angle setting at different moments in the time-rotation angle fitting curve of the steering gear 6, and the rotation angle of the steering gear 6 is adjusted through the PWM signal.

[0083] It should be noted that the high-level pulse width of the PWM signal controls the steering gear 6 to rotate to different angles. In a specific embodiment, when the arm is closed (the arm deflection angle is 0°), the PWM signal is 1980HZ; when the arm is extended (the arm deflection angle is 90°), the PWM signal is 105HZ.

[0084] In addition, the above-mentioned preset frequency is the adjustment frequency of the PWM signal, which can be set according to actual needs, for example, it can be set to 400HZ.

[0085] Preferably, if Figure 8 As shown in , the control method also includes:

[0086] The sent PWM signal is counted, and if the count value reaches the set threshold, the sending of the PWM signal is stopped.

[0087] In this embodiment, when the count value reaches a set threshold, the arm is fully extended, thereby achieving smooth arm extension control.

[0088] Specifically, the above-mentioned threshold value is set according to the maximum rotation time (arm extension time) of the steering gear 6 and the sending frequency of the PWM signal.

[0089] The present invention also provides a control system for a controllable fast folding machine arm. The control system includes: a discrete module, a fitting module and a control module. The discrete module is used to obtain the time-rotation angle discrete data of the servo 6 during the machine arm deployment process according to the fastest curve; the fitting module is used to fit the time-rotation angle discrete data through a selected fitting function to obtain the time-rotation angle fitting curve of the servo 6; the control module is used to control the rotation angle of the servo 6 at different times during the machine arm deployment process according to the time-rotation angle fitting curve of the servo 6, so that the speed of the arm is zero when the arm is deployed to the maximum rotation angle.

[0090] Specifically, the control module includes: a signal conversion module and a signal sending module. The signal conversion module is used to obtain the rotation angles at different times during the arm deployment process according to the time-rotation angle fitting curve of the servo 6, and convert them into corresponding PWM signals; the signal sending module is used to send a PWM signal to the servo 6 at a preset frequency when receiving the arm deployment signal, so as to control the rotation angle of the servo 6.

[0091] Preferably, the control module further comprises a counting module, and the counting module is used to count the sent PWM signals, and if the count value reaches a set threshold, the signal sending module stops sending the PWM signal.

[0092] Preferably, the control system and the steering gear 6 are powered by a power supply, a first voltage stabilizer is provided between the power supply and the control system, and a second voltage stabilizer is provided between the power supply and the steering gear 6. Fig. 9 as shown in .

[0093] Among them, by setting a voltage stabilizer, the power supply voltage is kept stable, which is beneficial to the stable operation of the control system and the steering gear 6.

[0094] The embodiment of the present invention provides a controllable fast folding machine arm, such as Fig. 9 As shown. The controllable fast folding machine arm adopts the control method and / or the control system as described above to control its arm extension process. The controllable fast folding machine arm comprises: a machine arm, a steering gear 6 and a folding mechanism. When the steering gear 6 rotates, the machine arm is driven to unfold to a preset angle through the folding mechanism.

[0095] Among them, Fig.10 As shown, the folding mechanism includes: a steering gear bracket 1, an arm connecting rod 2, a U-shaped mounting frame 3, a connecting rod 4, and a steering gear arm 5. The steering gear 6 is fixedly mounted on the steering gear bracket 1, and the steering gear arm 5 is arranged on the steering gear 6. The U-shaped mounting frame 3 is fixedly connected to the steering gear bracket 1, and the arm connecting rod 2 is rotatably arranged on the U-shaped mounting frame 3. The arm connecting rod 2 is fixedly connected to the arm, and the two ends of the connecting rod 4 are respectively hinged to the steering gear arm 5 and the arm connecting rod 2.

[0096] In the present invention, the structure of the folding mechanism is improved, the structure is simple, and the machine arm can be driven to fold more than 90 degrees.

[0097] Servo bracket 1: Its main function is to fix the servo 6 and connect the servo 6 to the U-shaped mounting frame 3. The design of the servo bracket 1 takes into account the installation angle of the servo 6 and the stability of the mechanism. Through precision processing and optimized structure, the servo 6 is closely connected with other components, thereby achieving stable control of the folding and unfolding of the machine arm.

[0098] Arm connecting rod 2: Its main function is to connect the arm and the connecting rod 4 and provide stable support for the arm.

[0099] U-shaped mounting frame 3: Its main function is to provide a stable support and connection point for the steering gear bracket 1 and the arm connecting rod 2, and to limit the upward tilt angle. By strengthening the connection method and reinforcing the structure, the U-shaped mounting frame 3 can withstand the torque and pressure when the arm moves, ensuring the reliability and durability of the mechanism during operation.

[0100] Link 4: It is designed to connect with the steering gear 6 and realize the folding and unfolding of the machine arm through the rotation of the steering gear 6. The shape and length of the link 4 are precisely calculated to realize the deflection of the machine arm more than 90 degrees and ensure the smoothness and accuracy of the mechanism movement.

[0101] Servo arm 5: Servo arm 5 is a key component of the folding mechanism, connecting the servo 6 and the connecting rod 4, and realizing the folding and unfolding of the arm by transmitting the rotational motion of the servo 6.

[0102] Preferably, in the embodiment of the present invention, the materials of the various components of the folding mechanism are mostly high-strength aluminum alloy materials, which have the characteristics of lightness and high strength, helping to reduce the weight of the entire mechanism while ensuring the stability of the mechanism under high-speed movement and complex environments.

[0103] During implementation, a plurality of, for example, four or six, controllable fast folding arms provided by the embodiment of the present invention are used in the drone, such as Fig.11 as shown in .

[0104] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware through a computer program, and the program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0105] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A control method for a controllable rapid folding machine arm, characterized in that: The controllable fast folding machine arm comprises: a machine arm and a steering gear, wherein the steering gear drives the machine arm to unfold to a preset angle by rotating. The control method comprises: Obtaining discrete data of the time-rotation angle of the servo during the arm deployment process according to the fastest curve; Fitting the time-rotation angle discrete data by a selected fitting function to obtain a time-rotation angle fitting curve of the steering gear; The rotation angle of the servo at different moments during the arm deployment process is controlled according to the time-rotation angle fitting curve of the servo, so that the speed of the arm is zero when the arm is deployed to the maximum rotation angle.

2. The control method according to claim 1, characterized in that: The equation of the brachistochrone curve is: x = R(θ-sinθ); y = R(1-cosθ); Where x is the x-axis coordinate, y is the y-axis coordinate, R is the radius of the cycloid circle, and θ is the rotation angle of the cycloid.

3. The control method according to claim 1 or 2, characterized in that: The step of obtaining the time-rotation angle discrete data of the servo during the arm deployment process according to the fastest curve includes: Get the x-axis discrete coordinates and y-axis discrete coordinates [(x1,y1)…(x n ,y n )]; The x-axis discrete coordinates are mapped to the rotation time of the servo, and the y-axis discrete coordinates are mapped to the rotation angle of the servo, so as to obtain the time-rotation angle discrete data of the servo during the arm deployment process [(0,0)…(T,ω max )], T is the maximum rotation time of the servo, ω max is the maximum rotation angle of the servo.

4. The control method according to claim 1 or 2, characterized in that: The fitting function includes an exponential decay function, and the formula of the exponential decay function is: ω=a-be -kt ; Where ω is the rotation angle of the servo, t is the time, and a, b, and k are the parameters to be fitted.

5. The control method according to claim 1 or 2, characterized in that: The controlling the rotation angle of the servo at different times during the arm deployment process according to the time-rotation angle fitting curve of the servo comprises: According to the time-rotation angle fitting curve of the servo, the rotation angles at different times during the arm deployment process are obtained, and converted into corresponding PWM signals; When the machine arm is unfolded, a corresponding PWM signal is sent to the servo at a preset frequency to control the rotation angle of the servo.

6. The control method according to claim 5, characterized in that: The control method further comprises: The sent PWM signal is counted, and if the count value reaches the set threshold, the sending of the PWM signal is stopped.

7. A control system for a controllable fast folding machine arm, characterized in that: The controllable fast folding machine arm comprises: a machine arm and a steering gear, wherein the steering gear drives the machine arm to unfold to a preset angle by rotating. The control system comprises: A discrete module, for obtaining discrete data of time-rotation angle of the servo during the arm deployment process according to the fastest curve; A fitting module, fitting the time-rotation angle discrete data by a selected fitting function to obtain a time-rotation angle fitting curve of the servo; The control module controls the rotation angle of the servo at different times during the arm deployment process according to the time-rotation angle fitting curve of the servo, so that the speed of the arm is zero when the arm is deployed to the maximum rotation angle.

8. The control system according to claim 7, characterized in that: The control module comprises: A signal conversion module, used to obtain the rotation angles at different times during the deployment of the arm according to the time-rotation angle fitting curve of the servo, and convert them into corresponding PWM signals; The signal sending module is used to send a PWM signal to the steering gear at a preset frequency when receiving the arm extension signal, so as to control the rotation angle of the steering gear.

9. The control system according to claim 7 or 8, characterized in that: The control system and the steering gear are powered by a power supply, A first voltage stabilizer is arranged between the power supply and the control system, and a second voltage stabilizer is arranged between the power supply and the steering gear.

10. A controllable fast folding machine arm, wherein the controllable fast folding machine arm adopts the control method described in any one of claims 1 to 6 and / or the control system described in any one of claims 7 to 9 to control its arm extension process, characterized in that: The controllable fast folding machine arm comprises: a machine arm, a steering gear and a folding mechanism. When the steering gear rotates, the machine arm is driven by the folding mechanism to unfold to a preset angle. The folding mechanism comprises: a steering gear bracket, an arm connecting rod, a U-shaped mounting frame, a connecting rod, and a steering gear arm, wherein the steering gear is fixedly mounted on the steering gear bracket, the steering gear arm is arranged on the steering gear, the U-shaped mounting frame is fixedly connected to the steering gear bracket, the arm connecting rod is rotatably arranged on the U-shaped mounting frame, the arm connecting rod is fixedly connected to the arm, and two ends of the connecting rod are respectively hinged to the steering gear arm and the arm connecting rod.

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