Design And Implementation Of Integrated Robot Trajectory And Servo Controller

Nowadays,most of the current industrial robots,multi-axis CNC machine tools,automated pipelines and other systems that require multiple servo motion control still use a distributed control method of a motion controller or trajectory control card with multiple servo drives,which results in many problems in practical applications,such as high system hardware redundancy,large control cabinet size,multiple and complicated internal module connections,poor synchronization of multi-axis motion,and high prices.Therefore,it is necessary to further simplify the system structure of the drive.In this paper,we firstly analyze the trajectory planning of a multi-axis robot by modeling the forward and inverse kinematics of the robot.Then designs and implements an Ether CAT bus interface based on the development trend of robot drive and control integration,which can control up to 8 servo motors of multi-axis integrated robot controller at the same time.We also adopt the dual-core mode of FPGA + STM32F407 to complement the advantages of ARM and programmable logic devices,fully realize the performance of STM32F407 while realizing multi-axis servo control logic in a single FPGA,greatly reducing the size of the robot controller.Then we use the multiplexing mode for the modules that consume more logic resources to save the logic resources of FPGA.What's more,we use the isolate phase current sampling method with pure resistance to increase the bandwidth of the current loop.We apply the integrated controller to the trajectory planning of the industrial six-axis robot,and use the sinusoidal acceleration and deceleration motion model to complete the smooth motion control of the robot trajectory.Then we use the Twin CAT software platform to compare and analyze the actual data from the robot driven by the controller and the simulation data of the trajectory algorithm,which verifies the feasibility of the motion control algorithm.Finally,we make each module boards of the integrated controller and assembled it with the shell to test the performance of the low-voltage power supply,the internal and external communication quality of the system,and the temperature rise of each module under long-term work.Then we monitor the servo by the Twin CAT master through the Ether CAT bus,and the result of test is as follow,the minimum distribution clock DC of Ether CAT is 1ms,and the synchronization error of the bus is within 30 ns,the response speed of the single-axis servo speed loop is 16 ms,and the position loop tracking time is within 100 ms,which shows the system has a high current bandwidth and strong capability of speed step response.