INVERSE DYNAMICS ANALYSIS AND SIMULATION OF A CLASS OF UNDER- CONSTRAINED CABLE-DRIVEN PARALLEL SYSTEM

摘要

For the under-actuated parallel system that 3 robots cooperatively hoist an object of 6 DOF by cables, Newton-Euler method is used to establish the dynamic equation of the system. It is considered that the end effector of each robot has three degrees of freedom in this paper. Therefore, when the position and pose of the object were known, there are 15 unknown parameters and 9 equations by the inverse dynamics analysis. Since that 9 equations can't be resolved to 15 unknown parameters, some methods for 3 cables towing the object with six degrees of freedom will be discussed in this paper. It can be solved by adding constraints to reduce the number of unknown quantities, which aims at achieving the purpose that one solution or a few amount of solutions. Then this paper is divided into two types of variable cable length and fixed cable length to discuss and the Matlab is used for simulation, which verifies the feasibility of the method and shows that the dynamics modeling is reasonable. It lays the foundation for further study.