چكيده به لاتين
Abstract:
Under-constrained cable driven robots have recently attracted more attention from researchers because of their simpler performance and lower cost than fully-constrained robots. The problem with such robots is their low operators and low-constraints. The works done on these robots mostly includes planar robots and point masses. Also, in cases where the robot is spatially discussed, all degrees of freedom haven’t discussed (especially the orientation of end-effector in space) are not discussed or analyzes as quasi-static.
In this thesis, we intend to study the dynamic behavior and path planning for under-constrained cable driven robot with 4 cables for moving in space and studying the position and orientation of its end effector with 6 degrees of freedom. Considering that direct kinematics in these robots does not have a unique solution, and for solving them it is necessary to analyze statics simultaneously; this thesis study the motions of a robot that begin motion in static and dynamic equilibrium. In this case, the robot will be completely determined at the beginning of the motion. Then, using inverse kinematic solution, we set the angles of the drums, and we push these angles as dynamic system inputs, and we compare the motion of the robot's end effector with the desired motions. In order to have the cables tensile positive, we have the weight of the body, which in a small acceleration motion causes the cables to stretch. The Lagrange method is used to model the dynamics of the robot and the cable is modeled as a linear spring. In applications where the mass of the cable is unobtrusive to the mass of the end effector, this model looks appropriate to avoid the complexity of the relationship.
The results indicate that the robot can achieve some degree of planar and spatial motion. Sometimes the increase or decrease in the length of cables changes instead of changing the position of the operator, and this is due to the problem of the robot have low operator.
Keywords: under-constrained, forward kinematics, linear spring, inverse kinematics
