Design And Error Analysis Of Two Degree Of Freedom Hanging Wire Gravity Compensation Mechanism

Two degree of freedom manipulator is widely used in space exploration equipment such as lunar rover to adapt to the micro low gravity environment on the surface of space or other planets.It is necessary to carry out micro low gravity experiments on the manipulator in the ground environment to obtain relevant parameters.Guide the design,manufacture and installation of the manipulator to make the performance of the manipulator achieve the expected effect.In this paper,a suspended gravity compensation device is designed.The device compensates the gravity of the two-degree of freedom two-stage series manipulator through the hanging wire and counterweight,simulates the microgravity environment of the lunar surface,and creates conditions for the microgravity experiment of the manipulator.Improving the accuracy of gravity compensation is an important goal of structural design.In order to improve the accuracy of gravity compensation,the source of compensation force error is systematically analyzed in this paper.Compensation force error mainly comes from three aspects:(1)geometric error caused by device structure and assembly;(2)Coupling vibration error caused by vibration of ground test system;(3)Inertia force error caused by the inertia of hanging wire(spring).In order to quantitatively compare the compensation force error caused by various influencing factors,a unified error evaluation index is set for various errors.Then establish a mathematical model for the error factors at all levels,directly obtain the influencing factors of various factors,evaluate the quantified errors at all levels according to the unified error evaluation index,and finally guide the design of the system.In this paper,the structural design demonstration,error source analysis,establishment of evaluation index,calculation of influence factors and series connection are combined to form a set of effective error analysis methods.Through error analysis,the structural design is guided.Theoretically,the gravity compensation error of wire hanging gravity compensation mechanism can be controlled at about 1%,which is of great significance to the design of similar devices.