Motion Planning Of Industrial Robot For High-speed Pick & Place Operation

With the stimulation of industrial demand and the incentive of national policy,industrial robots will play a crucial role in industrial production line.As the typical industrial operation,pick and place operation is widely existed in 3C,food,medicine and other fields,and the Delta robot is widely used in these fields with the advantages of high-speed and high-precision.Therefore,it is important for us to have a research on the motion planning for high-speed pick-and-place operation of Delta robot.In addition,with requirements for the higher speed and precision in semiconductor packaging applications,it is obvious that the flexibility of robot arm can not be ignored,thus making some research on motion planning of flexible robot is also significant.Based on the current requirements of pick-and-place operation,such as higher speed,lower energy-consumption,steady movement,obstacles avoidance and so on,we talk about motion planning for Delta robot with multi-conditions and multi-performance indices.Abundant research of motion planning is present on the kinematics,we also take the dynamic information into account,and build its dynamic model based on virtual work principle.Comprehensive consideration of the status requirements and researches,we take motion time,energy consumed and jerk as optimal performance indices,and also take the robot's kinematic,dynamic,and the planning parameters as constraints,then the motion planning is formulated as a math model of multi-objective optimization problem with nonlinear constraints.In order to obtain a smooth motion profile,this dissertation focuses on two kinds of motion planning which based on the continuous jerk.In terms of traditional motion planning for high-speed pick-and-place operation,the design of the path shape and velocity profile is separately.And we use a method of elliptical path,which coupled with modified sine cam velocity profile to meet with requirements aboved.Combining with the features of B-spline functions and the geometries of obstacles inside the workspace,we propose the method of motion planning with fifth-order B-spline curve to design its path and velocity together.The detailed schemes are listed as follow,one is setting the position constraints of the unknown control points of B-spline,one is designing the position of dispersed curve points,another is constraint with eccentricity of semiellipse and dispersed points.Finally,the corresponding multi-objective optimization problems are solved by NSGA-II and MODE,and we use the fuzzy average membership function method to analyze the pareto optimal front obtained by the aboved optimization algorithms,the best results are analyzed in this dissertation as well.In terms of the pick-and-place operation in high-speed and high-precision applications,obviously,the corresponding industrial robots trend to the development of lightweight.And then the flexibility of robot will increase largely.This dissertation mainly focuses on single degree of freedom flexible robot,the Lagrange method and the Finite Element Method(FEM)are applied to build its dynamic model.Meanwhile,we use triangular velocity profile to achieve the motion planning,then take the tracking error of the end-point position in the final time as the optimal index to get the optimization problem.Based on the information above,we can design its structural parameters and control parameters together.Finally,the optimal results are obtained by GA,and also be analyzed in this dissertation.