A Method to Avoid Singularity of the Planar Four-Bar Linkage by Means of Self-Adaptive Structure

The singularity, namely, the output movement of the mechanism is uncertain due to kinematic bifurcation at the singular position, is the intrinsic characteristic of mechanism, resulting in movement out of control. To find a practical solution for this vexed question to make mechanism able to avoid its singular position is the greatest challenge in the field of mechanism. Based on the study of the planar four-bar linkage with singularity, the ideology of introducing self-adaptive mechanism theory into the solution of avoid singularity problem is firstly put forward in this paper. Using self-adaptive mechanism to complement the out of control parameters of singular position can make the mechanism have the ability to avoid singularity. Then the mechanism passes through the singular position smoothly with determined movement and load capability. Finally, the purpose of avoiding singularity is achieved.