Analysis of configuration space of flexible parallel joints driven by group of pneumatic artificial muscles

The 4-SPxyzS/Sxyz parallel bionic joint, which is driven by group of four pneumatic artificial muscles, was built by adding constraint branch. The dominant equation of the inverse kinematics solution was obtained. To solve the direct kinematics problem, a BP neural network is established by considering some special outputs (i.e. length of the driving branch) of the inverse kinematics solution as the BP neural network´s inputs and the corresponding inputs as the BP neural network´s outputs. And the constraint condition of solving the configuration space of 4-SPxyzS/Sxyz parallel mechanism was built. The configuration space was analyzed in theory by comparing the two configuration spaces obtained by the BP neural network and the inverse kinematics solution.