Potentiometer jack adjusting method based on fuzzy compliant control algorithm

Abstract

The invention discloses a potentiometer jack adjusting method based on a fuzzy compliant control algorithm, and relates to the technical field of aviation airborne equipment debugging, and the method comprises the following steps: guiding a screwdriver to be inserted into a resistance value adjusting hole, collecting a force signal, a force change rate, a torque signal and a torque change rate of the contact of the screwdriver and the resistance value adjusting hole through a force sensor, and calculating a resistance value of the resistance value adjusting hole; fuzzification processing is carried out to obtain a fuzzy force signal, a fuzzy force change rate, a fuzzy torque signal and a fuzzy torque change rate; performing fuzzy reasoning according to the fuzzy force signal, the fuzzy force change rate, the fuzzy torque signal, the fuzzy torque change rate and a preset fuzzy control rule to obtain a step length vector and an angle vector of the screwdriver; and according to the step length vector and the angle vector, the mechanical arm controls the screwdriver to conduct position and posture adjustment. The position and posture of the screwdriver can be actively adjusted by combining information fed back by the force sensor with a fuzzy compliance control algorithm, and therefore the jamming phenomenon in the hole inserting process is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of aviation airborne equipment debugging, and in particular to a potentiometer jack adjustment method based on a fuzzy compliance control algorithm. Background Art

[0002] The fly-by-wire computer is an important component in the aircraft flight control system. There are several circular potentiometers on the adjustment panel of each analog fly-by-wire computer. When debugging the aircraft flight control system on the ground, it is necessary to manually use a screwdriver to insert into the potentiometer jack to adjust the potentiometer resistance. Due to the large number of potentiometers and the small size of the potentiometer jack, the manual adjustment method is inefficient and has poor consistency.

[0003] A Chinese patent (application number CN202210319684.6, published on March 15, 2024) discloses a method for automatic debugging of a telex computer potentiometer, in which the overall image of the potentiometer adjustment panel is sampled through a visual module, and the position of each potentiometer in the robotic arm coordinate system is obtained using a linear processing operation method and a coordinate system conversion, and then the action of inserting the screwdriver at the front of the robotic arm into the potentiometer resistance adjustment hole is completed. However, due to factors such as errors in the screwdriver's posture or the unsatisfactory consistency of the potentiometer adjustment square hole, the screwdriver is prone to jamming when inserted into the adjustment square hole, and cannot continue to move downward, making it impossible to debug the potentiometer.

[0004] A Chinese patent (application number CN202411163477.1, published on October 22, 2024) discloses an adaptive compliance control method for articulated industrial robots based on impedance learning, in which an impedance control model describing the dynamic relationship between the end force and the end position of the robot is established, and an impedance learning method is used to update the impedance parameters in real time according to the end position control error and the contact force, so as to control the movement of the industrial robot based on the end position or the end contact force. However, for the dynamically changing contact force generated when a screwdriver with different postures is inserted into the square hole of the potentiometer to adjust the position, this method cannot accurately give a mathematical model to express the relationship between the contact force and the posture error.

[0005] Therefore, how to provide a potentiometer jack adjustment method based on a fuzzy compliant control algorithm, which can actively adjust the screwdriver posture by using the information feedback from the force sensor combined with the fuzzy compliant control algorithm, thereby avoiding jamming during the jack insertion process is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] In view of this, the present invention proposes a potentiometer jack adjustment method based on a fuzzy compliant control algorithm, aiming to solve the technical problem that the above-mentioned traditional electric computer potentiometer automatic debugging method is prone to cause the screwdriver inserted into the adjustment square hole to get stuck, and the automatic adjustment of the potentiometer resistance cannot be completed smoothly.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] The present invention provides a potentiometer jack adjustment method based on a fuzzy compliance control algorithm, comprising the following steps:

[0009] Step 1: The visual system guides the screwdriver to be inserted into the resistance adjustment hole of the potentiometer, and the force sensor is used to collect the force signal, force change rate, torque signal and torque change rate when the screwdriver contacts the inner wall of the resistance adjustment hole;

[0010] Step 2: fuzzy the collected force signal, force change rate, torque signal and torque change rate to obtain a fuzzy force signal, a fuzzy force change rate, a fuzzy torque signal and a fuzzy torque change rate;

[0011] Step 3: Perform fuzzy reasoning according to the fuzzy force signal, the fuzzy force change rate and the preset fuzzy control rule to obtain a step vector for adjusting the position of the screwdriver; perform fuzzy reasoning according to the fuzzy torque signal, the fuzzy torque change rate and the preset fuzzy control rule to obtain an angle vector for adjusting the posture of the screwdriver;

[0012] Step 4: According to the step vector and the angle vector, the robotic arm controls the screwdriver to adjust the position and posture so as to insert the screwdriver into the resistance adjustment hole without obstruction.

[0013] The potentiometer jack adjustment method based on the fuzzy compliant control algorithm of the present invention can, on the basis of existing equipment, design fuzzy control rules based on the fuzzy compliant control algorithm and determine the step size and angle of the screwdriver adjustment in combination with the information fed back by the force sensor without increasing the investment in additional hardware equipment and without significantly increasing the amount of calculation, thereby avoiding jamming during the jack insertion process, thereby reducing damage to the potentiometer and improving the working efficiency of the automatic adjustment system.

[0014] As a further improvement of the above technical solution, the force fuzzification steps are as follows: the domain of the contact force between the screwdriver and the resistance adjustment hole of the potentiometer is set to [-1,1]; negative, zero, and positive language values ​​are used for description; the membership function of the subset being zero adopts a trigonometric function; the membership functions of the subset being negative and the subset being positive both adopt a trapezoidal function;

[0015] The fuzzification steps of the force change rate are as follows: set the domain of the contact force change rate between the screwdriver and the resistance adjustment hole of the potentiometer to [-2,1]; take three language values ​​of negative, zero, and positive for description; take five language values ​​of negative large, negative medium, negative small, positive small, and positive large; the membership functions of the subsets of negative medium, negative small, and positive small use trigonometric functions, and the membership functions of the subsets of negative large and positive large both use trapezoidal functions.

[0016] As a further improvement of the above technical solution, the fuzzification steps of the torque are as follows: the domain of the contact torque between the screwdriver and the resistance adjustment hole of the potentiometer is set to [-0.1, 0.1]; negative, zero and positive language values ​​are used for description; the membership function of the subset being zero adopts trigonometric function; the membership functions of the subset being negative and the subset being positive both adopt trapezoidal function;

[0017] The fuzzification steps of the contact torque change rate are as follows: set the domain of the contact torque change rate between the screwdriver and the resistance adjustment hole of the potentiometer to [-2,1]; take negative, zero, and positive values ​​for description; take five language values ​​of negative large, negative medium, negative small, positive small, and positive large; the membership functions of the subsets of negative medium, negative small, and positive small use trigonometric functions, and the membership functions of the subsets of negative large and positive large both use trapezoidal functions.

[0018] As a further improvement of the above technical solution, the fuzzification steps of the step length are as follows: the domain of the step length is set to [-0.14, 0.14]; seven language values ​​are taken: negative large, negative medium, negative small, zero, positive small, positive medium, and positive large, and the membership functions all use trigonometric functions.

[0019] As a further improvement of the above technical solution, the fuzzification steps of the angle are: setting the domain of the angle to [-10,10]; taking seven language values ​​of negative large, negative middle, negative small, zero, positive small, positive middle, and positive large, and the membership functions all use trigonometric functions.

[0020] As a further improvement of the above technical solution, the fuzzy control rules adopt the form of if-and-then; the Mamdani method is selected as the fuzzy reasoning method, the fuzzy relationship generation rules in the Mamdani method are defined by performing a minimum operation between sets, and the reasoning synthesis rules adopt the maximum-minimum synthesis method.

[0021] As a further improvement of the above technical solution, in step three, the step vector and the angle vector are defuzzified using a centroid method.

[0022] As a further improvement of the above technical solution, a visualization interface of fuzzy rules is obtained through the MATLAB fuzzy toolbox to verify the effectiveness of fuzzy control.

[0023] As a further improvement of the above technical solution, the fuzzy control rules include:

[0024] If the direction of the current contact force is negative and the rate of change of the force is large and negative, then this adjustment is a moderate step length in the negative direction;

[0025] If the direction of the current contact force is negative and the rate of change of the force is negative, then this adjustment is a smaller step in the negative direction;

[0026] If the direction of the current contact force is negative and the rate of change of the force is small, then this adjustment is a moderate step in the negative direction;

[0027] If the current contact force is in a negative direction and the rate of change of the force is small and positive, then this adjustment is to a moderate step length in the negative direction;

[0028] If the current contact force is in a negative direction and the rate of change of the force is positive, then this adjustment is made to a larger step in the negative direction;

[0029] If the current contact force is zero, the rate of change of the force is not considered and no further adjustments are made;

[0030] If the current contact force is in a positive direction and the rate of change of the force is negative and large, then this adjustment is to a moderate step size in the positive direction;

[0031] If the current contact force is in a positive direction and the rate of change of the force is negative, then this adjustment is a smaller step in the positive direction;

[0032] If the current contact force is in a positive direction and the rate of change of the force is small and negative, then this adjustment is a moderate step in the positive direction;

[0033] If the direction of the current contact force is positive and the rate of change of the force is small, then this adjustment is a moderate step in the positive direction;

[0034] If the direction of the current contact force is positive and the rate of change of the force is large, then this adjustment is a larger step in the positive direction.

[0035] As a further improvement of the above technical solution, the fuzzy control rules also include:

[0036] If the current contact torque is in the counterclockwise direction and the rate of change of the torque is negative, then this time the adjustment is to a moderate angle in the counterclockwise direction;

[0037] If the current contact torque is in the counterclockwise direction and the torque change rate is negative, then this adjustment is to a smaller angle in the counterclockwise direction;

[0038] If the current contact torque is in the counterclockwise direction and the rate of change of the torque is negative and small, then this adjustment is to a moderate angle in the counterclockwise direction;

[0039] If the current contact torque is in the counterclockwise direction and the rate of change of the torque is small, then this adjustment is to a moderate angle in the counterclockwise direction;

[0040] If the current contact torque is in the counterclockwise direction and the rate of change of the torque is positive, then this adjustment is to a larger angle in the counterclockwise direction;

[0041] If the current contact torque is zero, the rate of change of the torque is not considered and no further adjustments are made;

[0042] If the current contact torque is in the clockwise direction and the rate of change of the torque is negative, then this time the adjustment is to a moderate angle in the clockwise direction;

[0043] If the current contact torque is in the clockwise direction and the torque change rate is negative, then this adjustment is to a smaller angle in the clockwise direction;

[0044] If the current contact torque is in the clockwise direction and the rate of change of the torque is small and negative, then this adjustment is to a moderate angle in the clockwise direction;

[0045] If the current contact torque is in the clockwise direction and the rate of change of the torque is small and positive, then this adjustment is to a moderate angle in the clockwise direction;

[0046] If the current contact torque is in the clockwise direction and the rate of change of the torque is positive, then this adjustment is to a larger angle in the clockwise direction.

[0047] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a potentiometer jack adjustment method based on a fuzzy compliance control algorithm, which has the following advantages and beneficial effects:

[0048] 1. The potentiometer jack adjustment method based on the fuzzy compliant control algorithm of the present invention does not increase the investment in additional hardware equipment and does not significantly increase the amount of calculation. The fuzzy controller is designed based on the fuzzy compliant control algorithm to combine the information fed back by the force sensor to determine the step size and angle of the screwdriver adjustment, thereby avoiding jamming during the jack insertion process, reducing damage to the potentiometer, and improving the working efficiency of the automatic adjustment system.

[0049] 2. The potentiometer jack adjustment method based on the fuzzy compliant control algorithm of the present invention uses the torque signal and the torque change rate collected by the force sensor as input quantities to process and obtain the angle vector as the basis for adjusting the screwdriver posture. It can realize effective posture adjustment in complex situations of single-line contact and double-line contact between the screwdriver and the potentiometer resistance adjustment hole to prevent jamming. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0051] Figure 1 A schematic diagram of the structure of the potentiometer jack adjustment device of the present invention;

[0052] Figure 2 A schematic diagram of the installation state of the screwdriver and the force sensor of the potentiometer jack adjustment device of the present invention;

[0053] Figure 3 A schematic diagram of a state in which a screwdriver and a resistance adjustment hole of a potentiometer jack adjustment device of the present invention are in surface contact;

[0054] Figure 4 A schematic diagram of a state in which a single-line contact exists between a screwdriver and a resistance adjustment hole of a potentiometer jack adjustment device of the present invention;

[0055] Figure 5 A schematic diagram of two states of single-line contact between the screwdriver and the resistance adjustment hole of the potentiometer jack adjustment device of the present invention;

[0056] Figure 6 A schematic diagram of a double-line contact state between a screwdriver and a resistance adjustment hole of a potentiometer jack adjustment device of the present invention;

[0057] Figure 7 The structural block diagram of the position fuzzy controller of the present invention;

[0058] Figure 8 The structural block diagram of the attitude fuzzy controller of the present invention;

[0059] Fig. 9 The membership function image of the force F of the present invention;

[0060] Fig.10 The rate of change of force of the present invention Δ F The membership function image of ;

[0061] Fig.11 The membership function image of the moment M of the present invention;

[0062] Fig.12 The torque change rate Δ M The membership function image of ;

[0063] Fig.13 The step length U of the present invention S The membership function image of ;

[0064] Fig.14 Angle U of the present invention A The membership function image of ;

[0065] Fig.15 A rule observer of the position fuzzy controller of the present invention;

[0066] Fig.16 A rule observer of the attitude fuzzy controller of the present invention;

[0067] Fig.17 Input and output surface view of the position fuzzy controller of the present invention;

[0068] Fig.18 Input and output surface views of the attitude fuzzy controller of the present invention;

[0069] In the figure: 1. Base; 2. Robotic arm; 3. Screwdriver; 4. Force sensor; 5. Vision system; 51. Lens; 52. Camera; 53. Light source; 6. Host computer; 7. Potentiometer panel; 8. Potentiometer bracket; 9. Potentiometer; 91. Resistance adjustment hole. DETAILED DESCRIPTION

[0070] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0071] In the description of the present invention, it is necessary to understand that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0072] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0073] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0074] According to an embodiment of the present invention, Figure 1 and Figure 2 As shown, the potentiometer jack adjustment device includes: a base 1, a robotic arm 2, a screwdriver 3, a force sensor 4, a visual system 5 and a host computer 6; the robotic arm 2 is installed on one side of the base 1, and the potentiometer panel 7 is fixedly installed on the other side of the base 1 through a potentiometer bracket 8 and horizontally corresponds to the robotic arm 2; the force sensor 4 is installed at the end of the robotic arm 2, and the screwdriver 3 is installed at the tool connection end of the force sensor 4; the robotic arm 2, the visual system 5 and the force sensor 4 are all electrically connected to the host computer 6; the visual system 5 is used to collect the position information of the resistance adjustment holes of each potentiometer 9 on the potentiometer panel 7 in the coordinate system of the robotic arm 2 and send it to the host computer 6, and the host computer 6 controls the screwdriver 3 to insert into the resistance adjustment hole 91 of the potentiometer 9 through the robotic arm 2.

[0075] Specifically, the force sensor 4 is a six-axis force sensor; the FC-Medusa six-axis force sensor produced by the Swiss BOTA company can be selected. The force sensor 4 installed between the mechanical arm 2 and the screwdriver 3 is used to detect the force and torque applied by the inner wall of the resistance adjustment hole 91 to the screwdriver 3 during the process of inserting the screwdriver 3 into the resistance adjustment hole 91.

[0076] Specifically, the visual system 5 includes a lens 51, a camera 52 and a light source 53; the lens 51 is installed at the front end of the camera 52, and the light source 53 is installed at the end of the robot arm 2. The camera 52 is electrically connected to the host computer 6.

[0077] Specifically, a modeling analysis is performed on the process of inserting the screwdriver 3 into the resistance adjustment hole 91 of the potentiometer 9, as follows:

[0078] Under the guidance of the visual system 5, the robot arm 2 controls the screwdriver 3 to complete the hole search, and then the screwdriver can be inserted into the resistor adjustment hole 91. However, due to the influence of factors such as the error in the position of the screwdriver 3 or the unsatisfactory consistency of the resistor adjustment hole 91, there may be three types of contact between the screwdriver 3 and the inner wall of the resistor adjustment hole 91 during the insertion process: surface contact, single-line contact, and double-line contact. Figure 3 As shown, the surface contact between the screwdriver 3 and the resistor adjustment hole 91 is an ideal contact situation. At this time, the screwdriver 3 and the resistor adjustment hole 91 only have a lateral position error, and no angle error in posture. Figure 4 and Figure 5 As shown, the screwdriver 3 and the resistance adjustment hole 91 are both in single-line contact. The single-line contact is divided into two cases. One is single-line contact (see Figure 4 ), the other is a single-line contact (see Figure 5 ); In these two single-line contact situations, there is a position error and an angle error between the screwdriver 3 and the resistance adjustment hole 91. Figure 4 In the case of single-line contact, the force sensor 4 is subjected to a small force in the axial direction, and the screwdriver 3 can continue to move forward for a certain distance. Figure 5 In the single-line contact situation shown in the figure, the screwdriver 3 cannot move forward and is blocked. Figure 6 It is shown that the screwdriver 3 is in double-line contact with the resistance adjustment hole 91 , and there is a position error and an angle error of posture between the screwdriver 3 and the resistance adjustment hole 91 . The screwdriver cannot continue to move downward, and a jamming phenomenon occurs.

[0079] Specifically, for the design of the fuzzy control system, the fuzzy control system is two controllers with two inputs and one output, namely the position fuzzy controller and the attitude fuzzy controller; the position fuzzy controller is as follows: Figure 7 As shown, the two inputs are the force F collected by the force sensor and the force change rate Δ F , force change rate Δ F The definition of is:

[0080]

[0081] Where F t Represents the current contact force, F t-1 Represents the contact force before the last adjustment. The output is the step vector U S , including the direction and size of movement; the second system is Figure 8 As shown, the two inputs are the torque M collected by the force sensor and the torque change rate Δ M , torque change rate Δ M The definition of is:

[0082]

[0083] Where M t Indicates the current torque, M t-1 Indicates the torque before the last adjustment. The output is the angle vector U A , including the rotation direction and magnitude.

[0084] A potentiometer jack adjustment method based on a fuzzy compliant control algorithm comprises the following steps:

[0085] Step 1: The visual system guides the screwdriver to insert into the resistance adjustment hole of the potentiometer, and the force sensor is used to collect the force signal, force change rate, torque signal and torque change rate when the screwdriver contacts the resistance adjustment hole of the potentiometer;

[0086] Step 2: Fuzzy the collected force signal, force change rate, torque signal and torque change rate respectively to obtain a fuzzy force signal, a fuzzy force change rate, a fuzzy torque signal and a fuzzy torque change rate;

[0087] Step 3: Perform fuzzy reasoning based on the fuzzy force signal, the fuzzy force change rate and the preset fuzzy control rules to obtain a step vector for adjusting the screwdriver position; perform fuzzy reasoning based on the fuzzy torque signal, the fuzzy torque change rate and the preset fuzzy control rules to obtain an angle vector for adjusting the screwdriver posture;

[0088] Step 4: Based on the step vector and the angle vector, the robot arm controls the screwdriver to adjust its position and posture so as to insert the screwdriver into the potentiometer jack without obstruction.

[0089] In some embodiments, the input quantity is fuzzified, specifically:

[0090] (1) Fuzzification of force

[0091] The direction of the force F collected by the force sensor 4 determines the position adjustment direction of the screwdriver 3. F<0 means that the force direction is the negative direction of the coordinate axis of the force sensor 4; F>0 means that the force direction is the positive direction of the coordinate axis of the force sensor 4; F=0 means that there is no force. Therefore, the three language values ​​of "negative (N)", "zero (ZO)" and "positive (P)" are used for description. By observing the force sensor 4, it is found that even when it is stationary, it will still fluctuate between -0.3 and 0.3. That is to say, since the force sensor 4 is very sensitive, it should be assumed that there is no force in the range of -0.3 to 0.3. Therefore, considering the fluctuation of the force data collected by the force sensor 4, all values ​​of the force F within a certain range near zero are set to zero, so the membership function of the subset ZO adopts trigonometric function. If F<-1, the force is treated as -1, and if F>1, the force is treated as 1. Therefore, the membership functions of the subsets N and P adopt trapezoidal functions, and the domain of the force is set to [-1,1]. The membership function image of the force F is as follows Fig. 9 shown.

[0092] (2) Fuzzification of the rate of change of force

[0093] According to the rate of change of force Δ F The definition of is known. When Δ F <0, it means the force is reduced after adjustment. F = -1, indicating that the adjusted force is zero. F<-1, indicating over-adjustment, the force direction is reversed; F =0, it means the force remains unchanged after adjustment; when Δ F >0, it means that the force increases after adjustment, that is, the adjustment direction is wrong. In particular, when c=1, it means that the force after adjustment is twice that before adjustment. Therefore, the domain of the rate of change of force is set to [-2,1], and five language values ​​are taken: "negative large (NB)", "negative medium (NM)", "negative small (NS)", "positive small (PS)", and "positive large (PB)". The membership function of the subsets NM, NS and PS adopts trigonometric functions, and the membership function of the subsets NB and PB adopts trapezoidal functions. The rate of change of force Δ F The membership function graph is as follows Fig.10 shown.

[0094] (3) Fuzzification of torque

[0095] The direction of the torque M collected by the force sensor 4 determines the posture adjustment direction of the screwdriver 3. M<0 means that the torque is counterclockwise around the force sensor coordinate axis; M>0 means that the torque is clockwise around the force sensor coordinate axis; M=0 means that there is no torque. Therefore, the three language values ​​of "negative (N)", "zero (ZO)" and "positive (P)" are used for description. Since the torque data collected by the force sensor 4 fluctuates, all values ​​of the torque M within a certain range near zero are set to zero, so the membership function of the subset ZO uses trigonometric functions. If M<-0.1, the torque is treated as -0.1, and if M>0.1, the torque is treated as 0.1. Therefore, the membership functions of subsets N and P use trapezoidal functions, and the domain of the torque is set to [-0.1, 0.1]. The graph of the membership function of the moment M is as follows: Fig.11 shown.

[0096] (4) Fuzzification of the rate of change of torque

[0097] According to the torque change rate Δ M From the definition of , we know that when Δ M <0, it means the torque is reduced after adjustment. In particular, when Δ M =-1, indicating that the adjusted torque is 0; when Δ M <-1, it means over-adjustment, and the torque direction becomes the opposite direction. M =0, it means the torque remains unchanged after adjustment; when Δ M >0, indicating that the torque increases after adjustment. In particular, when Δ M=1, it means that the torque after adjustment is twice that before adjustment. Therefore, the domain of the rate of change of the torque is set to [-2,1], and five language values ​​are taken: "Negative Large (NB)", "Negative Medium (NM)", "Negative Small (NS)", "Positive Small (PS)", and "Positive Large (PB)". The membership function of the subsets NM, NS, and PS uses trigonometric functions, and the membership function of the subsets NB and PB uses trapezoidal functions. The rate of change of torque Δ M The membership function graph is as follows Fig.12 shown.

[0098] In some embodiments, the output is fuzzified, specifically:

[0099] (1) Fuzzification of step length

[0100] In the position fuzzy controller, the output is the step vector U S , its positive or negative indicates the moving direction, and its size indicates the moving step length. The domain of the step length is determined by the gap between the screwdriver 3 and the resistor adjustment hole 91, and the domain is set to [-0.14, 0.14]. In order to make the adjustment step length more precise, seven language values ​​are selected: "negative large (NB)", "negative medium (NM)", "negative small (NS)", "zero (ZO)", "positive small (PS)", "positive medium (PM)", and "positive large (PB)". The membership function uses trigonometric functions, and the step length U S The membership function graph is as follows Fig.13 shown.

[0101] (2) Angle blur

[0102] In the attitude fuzzy controller, the output is the angle vector U A , its positive and negative represent the direction of rotation, and its size represents the rotation angle. Its domain is set to [-10, 10]. In order to make the adjustment angle more precise, seven language values ​​are selected: "negative large (NB)", "negative medium (NM)", "negative small (NS)", "zero (ZO)", "positive small (PS)", "positive medium (PM)", and "positive large (PB)". The membership function uses trigonometric functions. The angle U A The membership function graph is as follows Fig.14 shown.

[0103] It should be noted that the vertical axis in the membership function graph is the membership, which describes the strength of a certain input variable belonging to a fuzzy set within a given range. The membership value range is 0-1, and the horizontal axis represents different input variables.

[0104] In some embodiments, the knowledge base of fuzzy control rules is established based on the behavior of a person inserting a screwdriver 3 into the resistance adjustment hole 91 on the surface of the potentiometer 9 as a reference, and its essence is a summary of practical experience and strategies.

[0105] For the position fuzzy controller, the input force F has three language values, the force change rate Δ F There are five language values, and 15 control rules can be specified in the form of if-and-then, as shown in Table 1.

[0106] Table 1 Control rules of position fuzzy controller

[0107]

[0108] For the attitude fuzzy controller, the input torque M has three language values, the torque change rate Δ M There are five language values, and 15 control rules can be specified in the form of if-and-then, as shown in Table 2.

[0109] Table 2 Control rules of attitude fuzzy controller

[0110]

[0111] The jamming phenomenon in the above three modeling situations can be avoided by combining the position fuzzy controller and the attitude fuzzy controller.

[0112] In some embodiments, fuzzy reasoning is an uncertain reasoning that determines output based on fuzzy relations and inputs. Considering that it is difficult to establish an accurate mechanical model for the process of inserting the screwdriver 3 into the resistance adjustment hole 91 on the surface of the potentiometer 9, and the adjustment of the screwdriver 3 posture during the insertion process needs to be fast and efficient, the Mamdani method is selected as the fuzzy reasoning method. In the Mamdani method, the fuzzy relationship generation rule is defined by performing a minimum operation between sets, and the reasoning synthesis rule adopts the maximum-minimum synthesis method.

[0113] In some embodiments, the centroid method uses the centroid of the area of ​​the graph enclosed by the membership function curve and the horizontal coordinate as the output value. Compared with the maximum membership method, the output of the centroid method is smoother and more responsive. Even if there is a slight change in the input, the output will change accordingly. The centroid method is suitable for defuzzification processes with high precision requirements. Considering the high precision required for the screwdriver 3 to be inserted into the resistance adjustment hole 91 on the surface of the potentiometer 9, the centroid method is used for defuzzification, and the calculation formula of the centroid method is:

[0114]

[0115] Among them, x* is the value of the defuzzified output; μ(x i ) is the membership function, that is, the possibility of the output value in each region of the membership function; x i is the fuzzy output quantity; n is the number of fuzzy sets.

[0116] In some embodiments, the MATLAB simulation of the fuzzy controller can obtain a visual interface of the fuzzy rules through the MATLAB fuzzy toolbox based on the membership functions of the input and output and the fuzzy rules established. Fig.15 The rule observer of the position fuzzy controller is shown as Fig.16 The figure shows the rule observer of the attitude fuzzy controller. The operator can directly add input values ​​in the rule observer interface to obtain specific output values, which is convenient for directly verifying the effectiveness of the fuzzy controller. Fig.17 The figure shows the input and output surface view of the position fuzzy controller, with the two horizontal axes representing the input F and Δ F , the vertical axis is the output U S .like Fig.18 The figure shows the input and output surface view of the attitude fuzzy controller, with the two horizontal axes representing the input M and Δ M , the vertical axis is the output U A The relationship between output and input can be intuitively seen through the input and output surface view. Fig.17 and 18 It can be seen that even if the input changes slightly, the output will change accordingly, which can meet the needs of the screwdriver to slightly adjust its posture during the insertion process.

[0117] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine different embodiments or examples described in this specification.

[0118] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A potentiometer jack adjustment method based on fuzzy compliance control algorithm, characterized in that: The following steps are involved: Step 1: The visual system guides the screwdriver to be inserted into the resistance adjustment hole of the potentiometer, and the force sensor is used to collect the force signal, force change rate, torque signal and torque change rate when the screwdriver contacts the inner wall of the resistance adjustment hole; Step 2: fuzzy the collected force signal, force change rate, torque signal and torque change rate to obtain a fuzzy force signal, a fuzzy force change rate, a fuzzy torque signal and a fuzzy torque change rate; Step 3: Perform fuzzy reasoning according to the fuzzy force signal, the fuzzy force change rate and a preset fuzzy control rule to obtain a step vector for adjusting the position of the screwdriver; Perform fuzzy reasoning according to the fuzzy torque signal, the fuzzy torque change rate and a preset fuzzy control rule to obtain an angle vector for adjusting the screwdriver posture; Step 4: According to the step vector and the angle vector, the robotic arm controls the screwdriver to adjust the position and posture so as to insert the screwdriver into the resistance adjustment hole without obstruction.

2. According to claim 1, a potentiometer jack adjustment method based on fuzzy compliance control algorithm is characterized in that: The steps of force fuzzification are as follows: set the domain of the contact force between the screwdriver and the resistance adjustment hole of the potentiometer to [-1,1]; use negative, zero, and positive language values ​​for description; the membership function of the subset being zero uses trigonometric function; the membership functions of the subsets being negative and positive both use trapezoidal function; The fuzzification steps of the force change rate are as follows: set the domain of the contact force change rate between the screwdriver and the resistance adjustment hole of the potentiometer to [-2,1]; take three language values ​​of negative, zero, and positive for description; take five language values ​​of negative large, negative medium, negative small, positive small, and positive large; the membership functions of the subsets of negative medium, negative small, and positive small use trigonometric functions, and the membership functions of the subsets of negative large and positive large both use trapezoidal functions.

3. According to claim 2, a potentiometer jack adjustment method based on fuzzy compliance control algorithm is characterized in that: The fuzzification steps of torque are as follows: set the domain of the contact torque between the screwdriver and the resistance adjustment hole of the potentiometer to [-0.1, 0.1]; use negative, zero, and positive language values ​​for description; the membership function of the subset being zero uses trigonometric function; the membership functions of the subsets being negative and positive both use trapezoidal function; The fuzzification steps of the contact torque change rate are as follows: set the domain of the contact torque change rate between the screwdriver and the resistance adjustment hole of the potentiometer to [-2,1]; take three language values ​​of negative, zero, and positive for description; take five language values ​​of negative large, negative medium, negative small, positive small, and positive large; the membership functions of the subsets of negative medium, negative small, and positive small use trigonometric functions, and the membership functions of the subsets of negative large and positive large both use trapezoidal functions.

4. According to claim 3, a potentiometer jack adjustment method based on fuzzy compliance control algorithm is characterized in that: The fuzzification steps of the step size are as follows: the domain of the step size is set to [-0.14, 0.14]; seven language values ​​are taken: negative large, negative medium, negative small, zero, positive small, positive medium, and positive large, and the membership functions all use trigonometric functions.

5. A potentiometer jack adjustment method based on fuzzy compliance control algorithm according to claim 4, characterized in that: The steps of fuzzifying the angle are as follows: set the domain of the angle to [-10,10]; take seven language values: negative large, negative middle, negative small, zero, positive small, positive middle, and positive large, and the membership functions all use trigonometric functions.

6. A potentiometer jack adjustment method based on fuzzy compliance control algorithm according to claim 5, characterized in that: The fuzzy control rules adopt the form of if-and-then; Mamdani method is selected as the fuzzy reasoning method. The fuzzy relationship generation rules in Mamdani method are defined by taking the smallest operation between sets, and the reasoning synthesis rules adopt the maximum-minimum synthesis method.

7. A potentiometer jack adjustment method based on fuzzy compliance control algorithm according to claim 6, characterized in that: In step three, the step vector and the angle vector are defuzzified using a centroid method.

8. The potentiometer jack adjustment method based on fuzzy compliance control algorithm according to claim 7, characterized in that: The visualization interface of fuzzy rules is obtained through MATLAB fuzzy toolbox to verify the effectiveness of fuzzy control.

9. A potentiometer jack adjustment method based on fuzzy compliance control algorithm according to claim 8, characterized in that: The fuzzy control rules include: If the direction of the current contact force is negative and the rate of change of the force is large and negative, then this adjustment is a moderate step length in the negative direction; If the direction of the current contact force is negative and the rate of change of the force is negative, then this adjustment is a smaller step in the negative direction; If the direction of the current contact force is negative and the rate of change of the force is small, then this adjustment is a moderate step in the negative direction; If the current contact force is in a negative direction and the rate of change of the force is small and positive, then this adjustment is to a moderate step length in the negative direction; If the current contact force is in a negative direction and the rate of change of the force is positive, then this adjustment is made to a larger step in the negative direction; If the current contact force is zero, the rate of change of the force is not considered and no further adjustments are made; If the current contact force is in a positive direction and the rate of change of the force is negative and large, then this adjustment is to a moderate step size in the positive direction; If the current contact force is in a positive direction and the rate of change of the force is negative, then this adjustment is a smaller step in the positive direction; If the current contact force is in a positive direction and the rate of change of the force is small and negative, then this adjustment is a moderate step in the positive direction; If the direction of the current contact force is positive and the rate of change of the force is small, then this adjustment is a moderate step in the positive direction; If the direction of the current contact force is positive and the rate of change of the force is large, then this adjustment is a larger step in the positive direction.

10. A potentiometer jack adjustment method based on fuzzy compliance control algorithm according to claim 9, characterized in that: Fuzzy control rules also include: If the current contact torque is in the counterclockwise direction and the rate of change of the torque is negative, then this time the adjustment is to a moderate angle in the counterclockwise direction; If the current contact torque is in the counterclockwise direction and the torque change rate is negative, then this adjustment is to a smaller angle in the counterclockwise direction; If the current contact torque is in the counterclockwise direction and the rate of change of the torque is negative and small, then this adjustment is to a moderate angle in the counterclockwise direction; If the current contact torque is in the counterclockwise direction and the rate of change of the torque is small, then this adjustment is to a moderate angle in the counterclockwise direction; If the current contact torque is in the counterclockwise direction and the rate of change of the torque is positive, then this adjustment is to a larger angle in the counterclockwise direction; If the current contact torque is zero, the rate of change of the torque is not considered and no further adjustments are made; If the current contact torque is in the clockwise direction and the rate of change of the torque is negative, then this time the adjustment is to a moderate angle in the clockwise direction; If the current contact torque is in the clockwise direction and the torque change rate is negative, then this adjustment is to a smaller angle in the clockwise direction; If the current contact torque is in the clockwise direction and the rate of change of the torque is small and negative, then this adjustment is to a moderate angle in the clockwise direction; If the current contact torque is in the clockwise direction and the rate of change of the torque is small and positive, then this adjustment is to a moderate angle in the clockwise direction; If the current contact torque is in the clockwise direction and the rate of change of the torque is positive, then this adjustment is to a larger angle in the clockwise direction.

Images