Research Of The Force-guide Teaching For Industrial Robots

With the development of industrial robot technology,the application of industrial robots in the actual production is more and more extensive.The robot programming is the premise and basis for correctly using robot.Common programming methods can be divided into flexpendant programming,off-line programming and direct programming.Using flexpendant programming requires the operator to have a certain understanding of the industrial robots.The operator controls industrial robot by a flexpendant,but this way is complicated and inefficient.Off-line programming can be used to plan the complex trajectory of the robot,which can be used for robot welding,grinding and polishing and so on.But programmers require mastering industrial robots.Direct teaching has the advantages of simple,intuitive and clear operation.The vision and force perception technology are commonly used in direct teaching.This paper puts forward the force-guiding method base on six-axis force sensor.The research and development of force-guiding teaching are based on ABB IRB120 industrial robot platform.The following research work has been carried out in this paper.Firstly,the force-drag flexpendent is designed according to the force-guiding teaching system requirements,which consists of six-axis force sensor,teaching-handle and connections.The force-drag flexpendant can be installed independently of the end of the industrial robots.The universality of the hardware part of the fore-guide teaching system is initially achieved.Based on the selected six-axis force sensor and data acquisition card,the design and buildup of hardware platform were accomplished.Then,the application development of six-axis force sensor is completed according to the chosen six-axis force sensor and data acquisition card.According to the installation way of the force-drag flexpendant and the end effector of the industrial robots,the relationship between robot base coordinate system,robot tool coordinate system and force sensors coordinate system are established.In order to ensure the accuracy of teaching,the compensation algorithm of gravity and gravity torque also included in the program.The correctness of the compensation algorithm is verified by experiments.Then,the forward and inverse kinematics for ABB IRB120 industrial robot is finished.With the help of Matlab software,the simulation model was established to simulate the correctness of forward and inverse kinematics.This paper proposed the algorithm of force following motion.The industrial robot motion was converted to the joint angle by inverse kinematics.The speed calculation is completed in the process of the force following motion.A computer automatically generates teaching playback program based on the stored data points to realize the playback of the industrial robot.Finally,the force-guide teaching experiments are performed on ABB IRB120 platform.The teaching operation of common trajectory and arbitrary curve's trajectory is completed on experimental board.And use the Douglas-Peuker sparse algorithm to optimize the trajectory of teaching points.At last,it is used for actual production of handling experiments.It is verified that the force-guide teaching system can effectively accomplish the task of direct teaching and meet the requirements of the actual production.