Research on Minimum Pressure Angle of Bennett Linkage

Space deployable structures that are constructed by the single loop over-constrained linkages have been extensively applied in the fields of aerospace and construction. The pressure angle regarded as an important index to measure the performance of the basic units has attracted more and more attention. The kinematic model of the Bennett linkage is studied by the D-H matrix and the analytic formula of the pressure angle has been deducted through kinematic equations. The rule of the Bennett linkage has been discovered that the minimum pressure angle occurs while the input angle equals nπ + π / 2(n ∈ N). According to the linkage configuration at the input angle of π / 2, the geometric meaning is revealed that the minimum pressure angle of the linkage is the same as the twist angle of the joint axes of the output link. Finally, conclusions can also be drawn that the smaller the twist angle of the output link is, the smaller the minimum pressure angle will be. The research enriches the kinematics of Bennett linkage and provides a reference for its engineering applications.