Design of Universal Joints for Heavy Loads

Abstract

Rotation requirement of joint is in two directions. It will replace three jacks of a leveling tripod with two jacks to reduce complexity. A joint with 2 DOF capability will be designed and developed for experimentation. The purpose of this project was to reduce complexity of the initial design and to study, design and develop a joint that fulfills the minimum DOF requirement for heavy loads. After the initial benchmarking and evaluation of possible joints, universal joint came out to be most appropriate for the tripod. After the Initial Design, kinematics analysis was performed on universal joint in which transformation matrices were calculated from base to the end effector. Kinematic Envelop was calculated keeping in mind the extreme movement of the tripod in order to control the movement of tripod. The angles calculated were used in transformation matrices to calculate joint linear velocities, accelerations and angular velocities and accelerations. Using the inertial load of the joint and applied force of 20T on universal joint, we calculated the forces and moments on all the extreme positions of tripod by applying these forces on kinematics equations that we calculated during kinematics analysis. Stress analysis was also performed on the universal joint during design stage which led us to our final design. Scaled down (1:5) universal joint was also designed and developed which was tested for load of 4T. The purpose was to compare the simulated results with experimental results and deduce our results of full scale model.