Development Of The Controller For A 4-Dof Palletizing Robot Based On EtherCat

Due to the increasing labor cost,it becomes an important trend to replace labors with robots.Palletizing robots are important compents in logistics automation and play a significant role in increasing productivity and decreasing labor cost.By years of development,domestic palletizing robots now have a significant progress.Howerver,the controllers of palletizing robots still mainly depend on freign products.Therefore,it has great significance to develop a native robot controller with high quality.According to the control requirement of pelletizing robots,a pelletizing robot controller based on the real-time Windows kernel extension and Ether CAT was developed in order to cut down the hardware cost.Some common real-time kernels and Ether CAT masters were firstly tested and compared.And a best real-time kernel and Ether CAT master were selected according to the comparion result.A human machine interface(HMI)in the Windows system and a real-time control program in the real-time kernel were developed.And thanks to the extensible feature of Windows,these two programs could run in the same industry PC.In order to fully use the computational resource of a multi-core processor,a multi-thread real-time control program was designed,and different threads were set different CPU affinity.Test results showed that this control system can fully satisfy the real-time requirement of the palletizing robot control system.Then the kinematic quations of the robot were derived by the geometric analysis of the robot and the dynamic equations of the robot were computed using the Lagrange Method.These equations can be used for the following collision detection and dynamic optimization.At last,a closed loop control method and a trapezoidal interpolation method were implemented in the joint space of the robot.And a filtering algorithm for the feedback encoder values was developed to filter the error values.The controller was tested in the real robot and the results shows that the robot can run smoothly and accurately using this controller.