Research On Instruction Design And Operation Optimization For PLC Motion Control

With the implementation of the intelligent manufacturing strategy,the manufacturing industry in China has been upgrading continuously,and a large number of high-end machinery and equipment with the core component of motion control,such as robots and computerized numerical control machines,have been and will be widely used in various industries.There are many technological solutions to realize motion control.Taking advantage of its technical versatility and compatibility,programmable logic controller(PLC)has been widely used in a range of industrial applications.In addition,PLC hardware has international and domestic standards,and its software is easy to develop and transplant.Most of the PLC products are based on foreign technology;however the open available literature of PLC-based motion control technology is scared.Based on the developing PLC-based motion control systems independently,this paper aims to tackle five key technologies of PLC motion control.1.To achieve high performance and high precision motion control,A hardware architecture of PLC motion control combining the dual-chip of embedded ARM and FPGA is designed to realize the motion control,where up to six 100 KHz high-speed pulses can be produced through the high-speed pulse arithmetic of FPGA.A pulse-based motion planning algorithm is designed in ARM chip,and the circuit of high-speed counter,double-axis pulse interpolation,pulse acceleration and deceleration and pulse compensator are designed in FPGA chip.The pulse compensator compensates the number of pulses by closed-loop counting according to the error of high-speed input counter and pulse output counter,so that the number of pulses in motion control is accurate.The closed-loop test of motion control pulse verifies the high performance and high precision of the designed motion control.2.A combination of motion control instruction sets is proposed to solve the problem of command matching in motion control scenarios.To attain flexible customization of motion control,embedded PLC software platform and programming software are studied carefully,where typical motion control instructions and special parameter setting instructions are designed respectively,including 195 flexible combinations of PLC instructions.It ensures the seamless integration of typical motion control instructions and PLC instruction system.The motion control application is developed using a unified PLC software platform to overcome the difficulty of flexible customization.In this paper,a duty cycle control method of pulse width modulation(PWM)is proposed to achieve the high performance motion control.The integrator compensation method is used to obtain higher precision of PWM actuator at lower frequency,which reduces the cost of PWM control technology.The proposed design is validated by the experiment of motion control cases.3.Aiming at the requirement of compiling and running motion control instructions,an efficient PLC programmable software combined lexical analyzer designed by open source FLEX,grammar analyzer desinged by open source BISON,self-designed semantics analysis and intermediate code generator.It guarantees the reliability and efficiency of compiling and interpreting motion control instructions.The maze algorithm is used to solve the problem of graphic element of ladder diagram recognition during compilation.The binary tree post-order traversal algorithm is used to compile and output instructions,and the binary tree series-parallel combination method is used to solve the compilation problem of multi-output in ladder diagram;the motion control instruction interpretation and operation module is designed;the compilation and conversion of multi-language motion control program is realized;and the running simulation experiment verifies the effectiveness of the motion control operation technology.4.A minimum fuel model is proposed to solve the problem of the flexibility of motion control and the optimization of the total amount of incentives.To realize flexible motion control,the shortest time control model and minimum fuel control model with constraints of speed,acceleration and urgency of motion control are established in consideration of the constraints of control variables and state variables such as performance index,mechanical inertia and hysteresis characteristics of machinery equipment.The optimal control algorithm of flexible acceleration and deceleration and the interpolation tracking algorithm of multi-axis linkage speed are designed accordingly.Furthermore,in the flexible motion control of S-type acceleration and deceleration control,the advantages of minimum fuel control model are studied,and a non-linear programming model and its algorithm are proposed for solving the minimum fuel control problem.The simulation example verifies its scientific merit and effectiveness.5.A rolling view monitoring optimization model is proposed for the first time to overcome the timeliness problem of refreshing remote debugging and monitoring data efficiently for motion control,and it can solves the dynamic access optimization management problem of human-computer interaction remote monitoring communication.The optimization model of updating monitoring data is put forward for the dynamic optimization of data packet-based communication,which takes the number of continuous data packets as the decision variable,the overall transmission time of refreshing the monitoring view as the optimization objective,and the human cognitive response as constraints.Through analyzing that the objective is a zigzag function and the unconstrained optimization model gives a lower bound,an approximately optimal solution can be obtained for the engineering application.The experimental simulation demonstrates the efficiency of the proposed optimization method in real-time PLC visual monitoring.