Dynamics Of Flexible Parallel Robot

With the continuous development of aerospace science and technology,precision and stability of mechanism must be further improved.In order to guarantee that the mechanism could move in the condition of high speed and light weight,a kind of analysis about kinematics and dynamics become a matter of urgency.Under the condition of high speed,light weight,heavy load,the deformation of component will definitely happen.That is to say,the deformable component will be used as the flexible component to analyze.Parallel robot has been one of the forefront topics in the field of robotics.The parallel robot has the advantages of small inertia,small accumulated error,high stiffness,large motion accuracy,stability,simple reverse kinematics and so on.The parallel robot makes up the gaps of the series robot in high speed,light weight and high precision.Therefore,flexible parallel robot with flexible mechanism and parallel mechanism becomes a very important research direction in the field of robotics.It is of great significance to carry out research in this area.On the basis of previous studies,the kinematics and dynamics of 3-RRRT parallel robot mechanism are modeled with three degree of freedom spatial parallel mechanism.Then the virtual prototype simulation is carried out.The force characteristics and dynamic characteristics of the mechanism are analyzed more comprehensively.Firstly,the coordinate system of 3-RRRT parallel robot is established in the joint by using the D-H coordinate method.The inverse kinematics,the angular displacement with the change of time,the angular velocity changes with time and the angular acceleration with the change of time can be obtained.Secondly,Newton Euler recursive method is used to analyze its recursive force.And the equilibrium equation of force and moment is established.Finally,the inverse dynamic solution is obtained by MATLAB.And the relation of driving torque with time is obtained.Then,the three-dimensional model is established with SOLIDWORKS,which is divided into three parts: moving platform,static platform,and the three branches(each branch of the chain of the three rods).Then the model is imported into ADAMS.The joint constraint is established.Simulation of inverse kinematics of rigid body and the forward dynamics are carried out.The driving torque curve and the force curve of the bar are obtained.Finally,the third bars of each branch in the ANSYS interface are divided into flexible grids.First,the parameters of material elastic modulus,Poisson's ratio,density is set.The format of output is MNF.Then the model is imported to ADAMS in order to replace the rigid body.Then the simulation of rigid flexible coupling is carried out(moving platform and the static platform belongs to the rigid body,the first and second rod of each branched is rigid,the third rod is flexible).The end track in rigid flexible mixture case is obtained.Then the characteristics of its trajectory and the curve of the stress of flexible rob are obtainedcompared with the state under rigid body.