Embedded Motion Controller Design And Servo Control Algorithm Research

With the increasingly widespread application of industrial robots and higher andhigher requirements of robot’s speed and movement precision, a kind of motioncontroller with good versatility, scalability, high stability and high-speed processingcapability is very important to achieve multi-axis industrial robot’s high-precision andhigh-speed control. At the same time, excellent control algorithm for better control ofthe robot is also very important. The main purpose of this project is to design aembedded motion controller with good scalability and high-speed processing capability,which can achieve the basic servo control functions. Meanwhile, do some research onthe servo control algorithm for the speed control of the dual-inertia resonant system.Firstly, for the Panasonic A5N drive, based on the embedded architecture andnetwork communication mode, a kind of multi-axis motion controller hardwareplatform design was proposed. It is based on the modular control core (ARM+FPGA)and can adapt to the New real-time network communication RTEX. The Multi-CPUdistributed control architecture was adopted. ARM9processor is used as the host CPU,which is responsible for the system management, human-computer interaction,trajectory planning, etc. And FPGA works as the coprocessor which is mainlyresponsible for the network communications and the underlying servo control functions.ARM and FPGA connects with each other through the SPI bus, while the RTEXnetwork communication between motion controller and driver chip is realized by thechip MNM1221. ARM and FPGA were both embedded into the controller backplane asthe modular core board. The backplane is mainly used to complete the voltageconversion and supply, and implement various communication interface functions. As tothe controller’s software part, the Windows CE operating system was embedded and thenetwork communication program and the underlying servo control program werecompleted in FPGA.Through the above design, the motion controller has the ability torun independently. In addition, through the motion controller’s USB master and slaveport, COM port, Ethernet port and other interfaces, the motion controller can beconnected to PC/IPC or the remote teaching box, etc to constitute the PC mode motioncontroller. Till now, the motion controller possesses the functions of speed control andposition control.The experiment platform was completed through the combination of the A5N drivecontrol cabinet, A5no-load motor, SCARA robot and the designed motion controller.Based on this experimental platform, the experiments of communication, speed controland position control were conducted. The no-load motor and SCARA robot werecontrolled to work in low, medium and high speed in speed and position mode respectively. The embedded motion controller’s communication capability and servocontrol functions were verified through the experiments. Through the measurement andanalysis of the actual speed, the motor output torque, the number of encoder pulses andother indicators, it was shown that the control system can achieve high-speed and high-precision motion control well.In addition, the speed control methods of the industrial robots with high speed,large inertia ratio, and flexible transmission link such as SCARA robot were explored inthe paper. Through dynamic analysis, a dual-inertia resonant system model wasestablished according to the parameters of the SCARA robot’s first axis. The twodegrees of freedom speed controller and all-state feedback speed controller weredesigned based on this model and tuned by different controller gain tuning methods. Itwas verified by the simulation results that the dual-inertia resonant system can be wellcontrolled by the designed control systems. By comparing the performance curves, theadvantages and disadvantages of the two speed controller and the different gain tuningmethods’s effects on the performance of the same controller were analyzed.