This study focused on the bifurcation of coordination relationships between McKibben pneumatic actuators (MPA). We aimed to arrive at the control theory of a robot with MPAs by analyzing this bifurcation phenomena. The control law using the MPA tension generates multiple motion modes, and the coordination relationships between MPAs bifurcate depending on parameters reported in a previous study. The bifurcation phenomenon between two of those coordination relationships was analyzed and it was found that despite a similar link movement, the phase oscillators exhibited different coupled modes. The important difference between two coupled modes was determined to be the relationship between the MPA pressure and length. Further, we verified that the angular velocity of the link was the parameter that generated this phenomenon by analyzing it in correspondence with the model of forced oscillation. In addition, we confirmed the bifurcation phenomenon employing a 1-DOF pendulum machine.

The steady-state analysis and design of a generalized class-E rectifier are reconsidered from circuit simulation techniques. From the considerations, we identify that this method corresponds to the harmonic balance method via the circuit partitioning technique to enhance the convergence of the Newton-Raphson method. Then, we extend this method using discrete Fourier transforms. Moreover, the nonlinear circuit model is incorporated to the steady-state analysis and design. Thus, we can obtain accurate design characteristics within the circuit simulation level. Although the harmonic balance method is well-known in circuit simulation studies, the related papers abstractly describe the algorithms. Hence, we describe our method as concrete as possible to compensate for the ambiguousness.