Theoritical Study Of A Novel 4-DOF Of Parallel Manipulator Using A Rotational Driving And Three Tilted Translational Drivings

With the deepening of research on parallel mechanism,people gradually found that limited-DOF parallel manipulators have a wide range of application prospects in medical devices,rapid sorting and many other fields,which requires people to continuously explore and create more new limited-DOF parallel manipulators with good mechanism characteristics.Therefore,a novel 4-DOF parallel mechanism(3PSS + RRPR parallel mechanism)is proposed,and its main characteristics are studied and analyzed theoretically.The mechanism has three linear drives and one rotary drive,it can achieve larger workspace and effectively avoid self-fretting caused by structural coupling.The three-dimensional solid model of the mechanism is established,it's inverse displacement is analyzed and the correctness of the result is verified.Based on the velocity projection theorem,the motion Jacobian sub-matrix of the mechanism is deduced.By analyzing the constraints of the limited-DOF parallel manipulators,the complete 6 × 6 form Jacobian of the 3PSS + RRPR parallel mechanism with the constraint / moment Jacobian matrix is obtained.,and then derive a 6 × 6 × 6 form Hessian matrix,establish the kinematic model of the mechanism,and verify the correctness of the model through the kinematics simulation by the computer.The static model of the 3PSS+RRPR parallel mechanism is established by the principle of virtual work,the dynamic equations of the 3PSS+RRPR parallel mechanism are solved by the combination of Newton-Euler method and virtual work principle,and the correctness of the results is verified by dynamic simulation.Through the Jacobian matrix of 3PSS + RRPR parallel mechanism,the singularity of the 3PSS + RRPR parallel mechanism can be judged.Solving the 3PSS + RRPR parallel mechanism work space with several different configurations by using CAD variable geometry method.