Servo motor teaching control system based on PLC

Abstract

The invention relates to the technical field of robot teaching, and discloses a PLC-based servo motor teaching control system, which comprises a robot teaching control user terminal and a robot motion control service terminal, the robot teaching control user terminal selects a touch screen PLC all-in-one machine, and sends an operation instruction to the robot motion control service terminal to control a robot to complete an operation action; and the robot motion control service terminal performs processing according to the operation instruction to obtain teaching data, and controls a servo motor in the robot body to rotate in a mode of sending an instruction code to a servo controller to complete motion of the robot body. Aiming at industrial control PLC terminal equipment with limited computing power, the lightweight group authentication mechanism disclosed by the invention realizes the function of simultaneously authenticating a plurality of industrial control PLC terminal equipment in a multi-machine cooperation scene while reducing the calculated amount and communication overhead in an authentication process, and is convenient for simultaneously managing the plurality of industrial control PLC terminal equipment.

Description

Technical Field

[0001] The invention relates to the technical field of robot teaching, in particular to a servo motor teaching control system based on PLC. Background Art

[0002] Teaching programming, robot language and offline programming are three communication methods for operators to exchange data with industrial robots. The most widely used method is teaching and reproducing. Teaching and reproducing robots are widely used in automobile and other mechanical manufacturing industries. Teaching and reproducing refer to the operator demonstrating the motion trajectory in advance, and the robot memorizes the program, position and related information during the demonstration process. Then, according to the reproducing instructions, they are taken out and analyzed one by one to control the robot to repeat the motion trajectory and control the motion accuracy within a certain range, so as to complete the required action. The teaching and reproducing method is divided into two teaching methods: hand-in-hand teaching and teaching pendant teaching. Using the teaching pendant to teach during the robot's movement can not only greatly improve the position accuracy, but also during the entire teaching process, the operator can monitor the emergency situations that may occur during the robot's movement in real time through some parameters in the teaching pendant and can respond quickly, greatly reducing the probability of major accidents.

[0003] With the rapid development of information and Internet technologies and their continuous extension and penetration into various industries, the original closed and isolated industrial control systems are gradually moving towards openness and interconnection. Internet technology has brought technological progress, increased productivity and greatly enhanced competitiveness to the field of industrial control. However, while enjoying these benefits, the field of industrial control is also facing increasingly severe information security challenges. Threats such as viruses and Trojans are spreading to industrial control systems.

[0004] In order to achieve good human-computer interaction performance, the current teaching control system of industrial robots generally adopts a solution of joint control of touch screen and programmable logic controller PLC. However, programmable embedded electronic devices represented by PLC have technical problems such as weak security protection capabilities, insufficient authentication mechanism and access control protection, and are easily invaded, which in turn causes damage to the entire system. Summary of the invention

[0005] The present invention provides a servo motor teaching control system based on PLC. In view of the general lack of authentication capabilities in current robot teaching control systems, a lightweight group authentication mechanism for industrial control PLC terminal devices is independently developed and designed. The identity authentication technology in traditional information security is improved to achieve the technical goal of simultaneously authenticating multiple PLCs in a multi-machine collaboration scenario in a servo motor teaching control system.

[0006] In order to achieve the above technical objectives, the present invention provides the following specific technical solutions:

[0007] PLC-based servo motor teaching control system, including robot teaching control user terminal and robot motion control service terminal;

[0008] The robot teaching control user terminal sends operation instructions to the robot motion control service terminal to control the robot to complete the operation action;

[0009] The robot motion control service terminal obtains teaching data according to the operation instructions, controls the rotation of the servo motor in the robot body by sending instruction codes to the servo controller to complete the movement of the robot body, and receives the parameter value sent back by the servo motor encoder to complete the feedback control of the servo motor;

[0010] When the servo motor teaching control system starts the teaching program, it first uses the lightweight group authentication method to authenticate the PLC terminal device in the robot motion control service terminal. If the authentication is successful, the teaching program is executed, otherwise the error symbol ⊥ is returned.

[0011] Preferably, the robot teaching control user terminal uses a touch screen PLC all-in-one machine, and the functions of the touch screen PLC all-in-one machine include teaching reproduction, robot operation file writing, monitoring robot operation status information and issuing operation instructions.

[0012] Preferably, the robot motion control service terminal adopts a distributed control mode, which is composed of a master control trusted PLC terminal device and n slave control trusted PLC terminal devices;

[0013] The master control trusted PLC terminal device obtains the teaching data through communication processing with the robot teaching control user terminal;

[0014] The slave trusted PLC terminal device controls the movement of the robot body by communicating with the robot body.

[0015] Preferably, the servo motor teaching control system uses a lightweight group authentication method to simultaneously authenticate n+1 trusted PLC terminal devices in the robot motion control service terminal.

[0016] Compared with the prior art, the present invention has the following beneficial technical effects:

[0017] For industrial control PLC terminal devices with limited computing power, the lightweight group authentication mechanism proposed in the present invention reduces the computing amount and communication overhead of the authentication process, while realizing the function of simultaneous authentication of multiple industrial control PLC terminal devices in a multi-machine collaboration scenario in a servo motor teaching control system, facilitating the simultaneous management of multiple industrial control PLC terminal devices, improving the system's authentication efficiency, and enhancing the system's security and reliability. DETAILED DESCRIPTION

[0018] Embodiment 1:

[0019] PLC-based servo motor teaching control system, including robot teaching control user terminal and robot motion control service terminal;

[0020] The robot teaching control user terminal uses a touch screen PLC integrated machine, which is responsible for processing the operator's operations, including teaching reproduction, robot operation file writing, etc. On the other hand, it receives the status information of the robot motion control service terminal, monitors the status information of the robot during operation on the graphical interface, and sends operation instructions to the robot motion control service terminal to control the robot to complete the corresponding operation action;

[0021] The robot motion control service terminal consists of a master trusted PLC terminal device and n slave trusted PLC terminal devices. The master trusted PLC terminal device and the slave trusted PLC terminal devices are in a distributed control mode with a multi-CPU structure.

[0022] The master control trusted PLC terminal device processes the teaching data according to different control commands through communication with the robot teaching control user terminal, and stores it in the external non-power-off random access memory RAM;

[0023] N slave-control trusted PLC terminal devices respectively control the movement of n joints of the robot. The slave-control trusted PLC terminal devices are responsible for communicating with the robot body. They control the rotation of the servo motor in the robot body by sending instruction codes to the servo controller of the servo motor to complete the movement of the robot body, and are assisted by corresponding algorithms to realize linear, joint, circular and other motion control, and can receive the parameter values ​​sent back by the servo motor encoder in real time to complete the feedback control of the servo motor.

[0024] Embodiment 2:

[0025] The robot teaching control user terminal exchanges data with the n+1 trusted PLC terminal devices of the robot motion control service terminal through serial communication or Ethernet communication, and authenticates the n+1 trusted PLC terminal devices of the robot motion control service terminal;

[0026] The robot teaching control user terminal includes a security monitoring module and a trusted credential generation module; the trusted credential generation module defines the communication rules for data interaction between the robot teaching control user terminal and the n+1 trusted PLC terminal devices of the robot motion control service terminal, specifically:

[0027] Rule I: e identifies the bilinear pairing function: G 1 ×G 2 →G T ;

[0028] Cyclic Group G 1 , G 2 and G T The order of is p, p>2 k , k is a safety parameter;

[0029] Group G 1 and Group G 2 Have isomorphism;

[0030] Q identifies group G 2 A generator of ;

[0031] Identification Group G 1 The generator of ; among them, is an isomorphic function;

[0032] g=e(P,Q) identifies the group G T The generator of

[0033] Rule II: H identifies a one-way hash function;

[0034] H 1 Identifies cryptographic hash function {0,1} * →Z p * ; {0,1} * Represents a binary sequence of any length consisting of 0s and 1s;

[0035] H 2 Identifies cryptographic hash function {0,1} l ×G 2 ×G T ×G 2 →Z p * ; {0,1} l represents a binary sequence of length l consisting of 0 and 1;

[0036] H 3 Identify the cryptographic hash function G 2 ×G T →{0,1} l ;

[0037] Rule III: Define a random polynomial of degree t-1 f(x) = a 0 +a 1 x+…+a t-1 x t-1 ;

[0038] Among them, the value a 1 , …, a t-1 ∈GF(p);

[0039] GF(p) consists of the elements in the set {0,1,...,p-1};

[0040] p>n+1≥t.

[0041] Embodiment three:

[0042] Based on the communication rules of the second embodiment, the trusted credential generation module implements the following operations, the specific process is:

[0043] Let P * =s * ×Q identifies the monitoring authority credentials of the security monitoring module; * ∈Z p * Identifies the intermediate parameters that assist in generating monitoring authority credentials;

[0044] ByU={U i |i=1,2,…,n,n+1} Identify the n+1 trusted PLC terminal devices of the robot motion control service terminal, obtain the device number of any trusted PLC terminal device and record it as x i ;

[0045] Output the trusted certificate d of any of the n+1 trusted PLC terminal devices of the robot motion control service terminal xi =P÷[s * +H 1 (x i )], and the monitoring permission credential P * and trusted credentials xi Transmit to trusted PLC terminal device;

[0046] Through U s Identify the robot teaching control user terminal, obtain the device number of the robot teaching control user terminal and record it as x s ;

[0047] Output the trusted credentials of the security monitoring module xs =P÷[s * +H 1 (x s )], and the monitoring permission credential P * and trusted credentials xs Transmitted to the security monitoring module.

[0048] Embodiment 4:

[0049] Based on the communication rules of the second embodiment, any one of the n+1 trusted PLC terminal devices of the robot motion control service terminal implements the following operations, and the specific process is as follows:

[0050] Calculate g xi =e(d xi ,T xi ), where the intermediate parameter T xi =P * +H 1 (x i )×Q;

[0051] If the equation g xi =g holds, then select a credible value X xi ∈Z p * ;

[0052] And calculate the trusted number K xi =X xi ×T xi , the trusted number K xi Transmit to the security monitoring module;

[0053] Otherwise, an error symbol ⊥ is returned.

[0054] Embodiment five:

[0055] Based on the communication rules of the second embodiment, the security monitoring module implements the following operations, the specific process is as follows:

[0056] Calculate g xs =e(d xs ,T xs ), where the intermediate parameter T xs =P * +H 1 (x s )×Q;

[0057] If the equation g xs =g holds, then select a credible value X xs ∈Z p * ;

[0058] And calculate the trusted number K xs =X xs ×T xs ;

[0059] Otherwise, an error symbol ⊥ is returned.

[0060] Embodiment six:

[0061] Based on the communication rules of the second embodiment, the security monitoring module performs a security authentication operation on any of the n+1 trusted PLC terminal devices of the robot motion control service terminal. The specific process is as follows:

[0062] Process 1: The security monitoring module constructs a security authentication information packet {f1 , f 2 , f 3 , f 4 , K xs , x s}, perform the following operations:

[0063] Order xi A trusted mark of a trusted PLC terminal device that identifies any trusted PLC terminal device among n+1 trusted PLC terminal devices of the robot motion control service terminal;

[0064] Calculate the trusted authentication information μ of any trusted PLC terminal device xi =H(s xi );

[0065] Among them, s xi =ASCⅠⅠ[f(x i )mod p]∈{0,1} l ; ASCII[·] means to take ASCII code operation;

[0066] Select the authentication number r belonging to any trusted PLC terminal device xi ∈Z p * ;

[0067] Based on the certification number r xi , combined with the trusted tags of the trusted PLC terminal devices xi and Trusted Number K xi , calculate the first auxiliary authentication information f 1 =s xi ⊕H 3 (r xi ×K xi , g^r xi );

[0068] Based on the certification number r xi , combined with the device number x of any trusted PLC terminal device i , monitoring authority credentials P * and parameter Q, calculate the second auxiliary authentication information f 2 =r xi ×T xi ;

[0069] Among them, the intermediate parameter T xi =P * +H 1 (x i )×Q;

[0070] Based on the certification number r xi , combined with the security monitoring module's own trusted credentials dxs , parameter g, trusted tag s of any trusted PLC terminal device xi and Trusted Number K xi , calculate the third auxiliary authentication information f 3 =[(r xi +h 2 )÷r xi ]×d xs ; Among them, the intermediate parameter h 2 =H 2 (s xi , f 2 , g^r xi , r xi ×K xi );

[0071] Based on the certification number r xi , combined with the trust value X of the security monitoring module itself xs , calculate the fourth auxiliary authentication information f 4 =X xs ×h 2 +r xi ;

[0072] Output security authentication information packet {f 1 , f 2 , f 3 , f 4 , K xs , x s}, and transmit it to any of the n+1 trusted PLC terminal devices of the robot motion control service terminal;

[0073] Process 2: Any of the n+1 trusted PLC terminal devices of the robot motion control service terminal receives the security authentication information packet {f 1 , f 2 , f 3 , f 4 , K xs , x s}After that, start to execute the following operations:

[0074] From the security authentication information packet {f 1 , f 2 , f 3 , f 4 , K xs , x s} to extract the first auxiliary authentication information f 1 , second auxiliary authentication information f 2 , third auxiliary authentication information f 3 , the fourth auxiliary authentication information f 4, the trusted number K of the security monitoring module xi and device number x s ;

[0075] Based on the trusted credentials of the trusted PLC terminal device itself xi and the credibility value X xi , calculate the trusted tag s' of the trusted PLC terminal device itself xi =f 1 ⊕H 3 (e(d xi , f 2 ), X xi ×f 2 );

[0076] And calculate the intermediate parameter h' accordingly 2 =H 2 (s' xi , f 2 , e(d xi , f 2 ), X xi ×f 2 );

[0077] Device number x that controls the user terminal according to robot teaching s , combined with the monitoring permission certificate P * and parameter Q, calculate T' xs =P * +H 1 (x s )×Q;

[0078] Calculate the first authentication code δ 1 =e(f 3 , f 4 ×T' xs -h' 2 ×K xs );

[0079] Calculate the second authentication code δ 2 =e(d xi , f 2 )×g^h' 2 ;

[0080] If the equation δ 1 =δ 2 If true, then calculate the trusted authentication information μ' xi =H(s' xi ), transmit the trusted authentication information μ to the security monitoring module;

[0081] Otherwise, an error symbol ⊥ is returned;

[0082] Process 3: The security monitoring module receives the trusted authentication information μ'xi After that, start the following operations:

[0083] If the equation μ' xi =μ xi If established, the authentication is successful, indicating that any of the n+1 trusted PLC terminal devices of the robot motion control service terminal is safe and reliable;

[0084] Otherwise, an error symbol ⊥ is returned;

[0085] At this point, the authentication process is complete.

Claims

1. The servo motor teaching control system based on PLC is characterized by: Including robot teaching control user terminal and robot motion control service terminal; The robot teaching control user terminal sends operation instructions to the robot motion control service terminal to control the robot to complete the operation action; The robot motion control service terminal obtains teaching data according to the operation instructions, controls the rotation of the servo motor in the robot body by sending instruction codes to the servo controller to complete the movement of the robot body, and receives the parameter value sent back by the servo motor encoder to complete the feedback control of the servo motor; When the servo motor teaching control system starts the teaching program, it first uses the lightweight group authentication method to authenticate the PLC terminal device in the robot motion control service terminal. If the authentication is successful, the teaching program is executed, otherwise the error symbol ⊥ is returned.

2. The PLC-based servo motor teaching control system according to claim 1 is characterized in that: The robot teaching control user terminal uses a touch screen PLC all-in-one machine. The functions of the touch screen PLC all-in-one machine include teaching reproduction, robot operation file writing, monitoring of robot operation status information and issuing operation instructions.

3. The PLC-based servo motor teaching control system according to claim 1 is characterized in that: The robot motion control service terminal adopts a distributed control method, which consists of a master control trusted PLC terminal device and n slave control trusted PLC terminal devices; The master control trusted PLC terminal device obtains the teaching data through communication processing with the robot teaching control user terminal; The slave trusted PLC terminal device controls the movement of the robot body by communicating with the robot body.

4. The PLC-based servo motor teaching control system according to claim 3 is characterized in that: The servo motor teaching control system uses a lightweight group authentication method to simultaneously authenticate n+1 trusted PLC terminal devices in the robot motion control service terminal.

5. The PLC-based servo motor teaching control system according to claim 4 is characterized in that: The lightweight group authentication methods are: The safety monitoring module of the robot teaching control user terminal constructs a safety authentication information data packet {f1, f2, f3, f4, K xs , x s }, perform the following operations: Order xi A trusted mark of a trusted PLC terminal device that identifies any trusted PLC terminal device among n+1 trusted PLC terminal devices of the robot motion control service terminal; Calculate the trusted authentication information μ of any trusted PLC terminal device xi =H(s xi ); Among them, s xi =ASCⅠⅠ[f(x i )mod p]∈{0,1} l ; ASCII[·] means to take ASCII code operation; Select the authentication number r belonging to any trusted PLC terminal device xi ∈Z p * ; Based on the certification number r xi , combined with the trusted tags of the trusted PLC terminal devices xi and Trusted Number K xi , calculate the first auxiliary authentication information f1 = s xi ⊕H3(r xi ×K xi , g^r xi ); Based on the certification number r xi , combined with the device number x of any trusted PLC terminal device i , monitoring authority credentials P * and parameter Q, calculate the second auxiliary authentication information f2 = r xi ×T xi ; Among them, the intermediate parameter T xi =P * +H1(x i )×Q; Based on the certification number r xi , combined with the security monitoring module's own trusted credentials d xs , parameter g, trusted tag s of any trusted PLC terminal device xi and Trusted Number K xi , calculate the third auxiliary authentication information f3 = [(r xi +h2)÷r xi ]×d xs ; Among them, the intermediate parameter h2=H2(s xi ,f2,g^r xi , r xi ×K xi ); Based on the certification number r xi , combined with the security monitoring module's own trust value X xs , calculate the fourth auxiliary authentication information f4 = X xs ×h2+r xi ; Output security authentication information data packet {f1, f2, f3, f4, K xs , x s }, and transmit it to any of the n+1 trusted PLC terminal devices of the robot motion control service terminal; Any of the n+1 trusted PLC terminal devices of the robot motion control service terminal receives the security authentication information data packet {f1, f2, f3, f4, K xs , x s }After that, start to execute the following operations: From the security authentication information data packet {f1, f2, f3, f4, K xs , x s } to extract the first auxiliary authentication information f1, the second auxiliary authentication information f2, the third auxiliary authentication information f3, the fourth auxiliary authentication information f4, and the trusted number K of the security monitoring module xi and device number x s ; Based on the trusted credentials of the trusted PLC terminal device itself xi and the credibility value X xi , calculate the trusted tag s' of the trusted PLC terminal device itself xi =f1⊕H3(e(d xi , f2), X xi ×f2); And calculate the intermediate parameter h'2 = H2(s' xi , f2, e(d xi , f2), X xi ×f2); Device number x that controls the user terminal according to robot teaching s , combined with the monitoring permission certificate P * and parameter Q, calculate T' xs =P * +H1(x s )×Q; Calculate the first authentication code δ1 = e(f3, f4×T' xs -h'2×K xs ); Calculate the second authentication code δ2 = e(d xi , f2)×g^h'2; If the equation δ1=δ2 holds, then the trusted authentication information μ' is calculated xi =H(s' xi ), transmit the trusted authentication information μ to the security monitoring module; Otherwise, an error symbol ⊥ is returned; The security monitoring module receives the trusted authentication information μ' xi After that, start the following operations: If the equation μ' xi =μ xi If established, the authentication is successful, indicating that any of the n+1 trusted PLC terminal devices of the robot motion control service terminal is safe and reliable; Otherwise, an error symbol ⊥ is returned; At this point, the authentication process is complete.