| The parallel robot is a branch. Compared with the traditional serial robot,parallel robot has the ring closed chain constraint between its foundation support and its end effector, which make it have low inertia movement,high load capacity,rigidity and other advantages. Because it has avoided the error accumulation effect of series robot joints,it make parallel robot become a hot topic in the field of robotics. Parallel robots have been widely used in machine tools, robots, force sensors and other fields.This paper mainly provides a two degree of freedom five bar parallel mechanism motion platform for laser operator. The key content is the research on the control system of the two degree of freedom five bar mechanism. The main research contents of this paper are as follows:(1)At first,the paper establishes mathematical modeling of the two degrees of freedom of the five-bar mechanism. And then it does the forward and inverse kinematics analysis and solution,the solution of velocity Jacobi matrix and the calculation of work splace,which is the preparation for the trajectory planning and simulation of the two degrees of freedom of the five-bar mechanism. The paper puts forward design requirements for the two degrees of freedom of the five-bar mechanism body in order to design the overall program and transmission scheme. the paper presents the selected laser head and laser driver control board. And it describes how to control them. This product has the advantage of a low cost,small size,light weight,stable performance and simple control. Then it analyzed the five bars in two degrees of freedom joint space the most frequently used method of trajectory planning and trajectory planning in real time.(2)The hardware in the control system of the article introduces the associated circuit diagram and the usage of FPGA dashboard. It introduces the selection and its working principle of AC servo motor and reduction box. In order to achieve the AC servo motor control,it designed the adapter plate specifically for FPGA controller. The adapter plate transforms the output differential feedback signal of AC motor drive to a unipolar signal which is input to the FPGA dashboard. And then it also introduced the control principle and control mode of AC servo motors.(3)Control system software section introduces the design process of the low machine code by the Quartus II software. And then it introduces the motion control process of the control system: FPGA dashboard collects the signal transmitted over through the serial communication by the LabVIEW software in PC. It is treated by FPGA dashboard. And then it is transformed to the pulse signal and the analog voltage signal which can be identified by AC servo motor,so that AC servo motor can make a response and make end effector to complete the assigned task. And it designs the servo motor control module by Verilog HDL,including level detection module,baud rate configuration of serial communication,a signal processing module and the motion control module of AC servo motor. What is more important,the paper uses LabVIEW software design PC interface. In this interface, you can set the parameters of two degrees of freedom five-bar mechanism, complete the line planning, arc planning, and calculation and simulation of work space. And data which has been calculated can be output to the FPGA dashboard through the serial.This design has completed the mathematical modeling of the structure of the body, forward/inverse kinematics solution, trajectory planning and the hardware design and software design of control system. Through the simulation and practical verification, it has proved that the design system is effective and feasible. |
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