Study On 2-DOF Planar Mechanism With Multiple Rotation Centers

In recent years,the research of parallel mechanism has been widely concerned by scholars at home and abroad.In the field of parallel mechanism,the two degree of freedom planar parallel mechanisms have good working space and flexibility.And it is easy to control.The planar parallel mechanism can be applied to medical and spray paint.If the planar mechanism is combined,the combined mechanism can be applied to the design of the snake robot.Snake robot can work in rugged environment which can complete the work of detection,search,investigation and so on.In this paper,a class of two degree of freedom planar mechanisms with multiple rotation centers is proposed.The mechanism is analyzed in depth,and a variety of mechanisms with the same kinematic properties are designed.A type of planar parallel mechanisms with two degrees of freedom is proposed.The structure and kinematics characteristics of the mechanism are analyzed in depth.The mechanism has two degrees of freedom.And the end actuators of planar parallel mechanism can rotate round the fixed point of a certain area in the plane and move along the vertical of the symmetrical line.The structure of the mechanism is symmetrical.Through the geometric relationship,the continuous motion characteristics of the mechanism are proved.The positive and negative solutions of the mechanism and the workspace of the mechanism are analyzed.Through the analysis of the structure characteristics and movement mode of the mechanism,the essential condition of the planar parallel mechanism with one rotation and one movement is analyzed.The angle between the middle plane and the branches that connect the base and the end effector is equal during the movement of the mechanism.Through the motion pair replacement and geometric method,many new configurations with the same kinematic nature have been designed.The equivalent rotation characteristics of the mechanism are proved.The motion planning for the equivalent rotation,continuous movement and continuous rotation of the mechanism are carried out.Numerical examples are given to verify the kinematics and kinematics of the mechanism.The experimental prototype is made on the basis of three-dimensional model.The two degree of freedom deployable mechanism and the multi free deployable mechanism are obtained,by combining the two degrees of freedom plane mechanism,The formers have the characteristics of enlarging the motion range,folding and unfolding.And the latter can realize the complex plane motion of multi degree of freedom.The workspace of the deployable mechanism with two degrees of freedom is analyzed.According to the characteristics of the deployable mechanism with multiple degrees of freedom,the prototype of the snake robot is designed and manufactured.