Research On Fault-tolerant Properties Of Redundant Manipulators

Compared to traditional non-redundant serial manipulator,redundant manipulator are more flexible and widely applied,because of its typical redundant properties.Therefore,it becomes hotspot on robotics research in the world.In this paper,take the 7R redundant manipulator developed by our own effort as example,combined with fault-tolerant performance research,the analysis and research about this manipulator's fault-tolerant properties were carried on.All the results led the way to improve the fault-tolerant theory of redundant manipulator,and gives an important instruction for the further research of redundant manipulator.The main content of this paper is shown as follows.1.In term of a 7R redundant manipulator with two offsets,improve the establishment method of coordinate because of the special structure,apply coordinate-modified D-H method to build the kinematics model,solve the kinematics equation,then validated by an example;2.Use Monte Carlo method to analyze the manipulator's workspace.Apply layer volume theory to workspace volume calculation and figure it out.Combine the 3-D modeling with numerical method to figure out the fault-tolerant workspace at the situation of single-joint locking model.Discuss the relationship between workspace and fault-tolerant workspace,the further optimization is carried out on the basis of exchange ration,the fault-tolerant workspace's influence rule is also studied on the basis of offset factor;3.Research on fault-tolerant properties of 7R redundant manipulator is carried out.Use differential transform method to solve the Jacobian of 7R redundant manipulator.Use SVD method to solve the singular value.On the basis of MATLAB platform,combined with minimum singular value and manipulability to evaluate the joint's fault-tolerant performance.4.Synthetically consider flexibility change before and after joint's failure,use relative manipulability and relative minimum singular value to analyze the joint's fault-tolerant performance,construct the new index to choose the fault-tolerant configuration.