Pneumatic anti-vibration apparatus (AVA) has been used for suppressing the vibration from the floor. Compressed air produced by the air compressor is supplied to air spring, which is used as an actuator in AVA. This paper considers the suppression of flow disturbance, which is caused by pressure variation of compressed air. Based on the internal model principle, the suppression of vibration of AVA due to flow disturbance has been confirmed by using Central Pattern Generator (CPG) in parallel with a displacement controller. In biological study, CPG in bodies playing a significant role in the walking have been learned. Moreover, mathematical models of CPG have been reported, and some researchers have been studying about walking of biped-robots by using CPG to generate desired value. On the other hand, this paper proposes asymmetric CPG as new model for further vibration suppression, compared with the symmetric CPG which is the conventional model. This new model introduces asymmetry by changing its parameters into different values in order to improve reproducibility of waveform which shows the variation of supplied air pressure. Validity of the proposed model is presented by experimental result of AVA. The effectiveness is shown by analyzing and comparing the results of experiment and simulation of symmetric and asymmetric CPGs.

Pneumatic anti-vibration apparatus (AVA) has been used for suppression of vibration from floor in the field like semiconductor manufacturing. The compressed air supplied to the pneumatic AVA is generated by the air compressor. During the compression process of the air, the pressure of the compressed air varies. Consequently, the pressure variation changes the flow rate of the air supplied to the pneumatic AVA, which is called flow disturbance. Based on the internal model principle, the suppression of vibration of AVA due to flow disturbance has been confirmed by using Central Pattern Generator (CPG). Previous studies in the field of biology have confirmed the existence of a neuronal network that generates a walking rhythm in the spinal cord of an organism, and this is called CPG. Some researchers have applied CPG to such as walking of biped-robots. However, there are no applications using information inside CPG. This letter proposes using internal information in CPG as new method for further vibration suppression, compared with the conventional method. Specifically, this method makes use of outputs corresponding to differential and integral signals inside the CPG. It is shown the effectiveness of the proposed method by experimental results.

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Pneumatic anti-vibration apparatus (AVA) has been used in order to suppress vibration from a floor. In this paper, central pattern generator (CPG) composed of reciprocal inhibition oscillator (RIO) model is applied for suppression of flow disturbance caused by pressure fluctuation of compressed air supplied to the pneumatic AVA. Concretely, the disturbance suppression is confirmed by implementing it to the control system of the AVA. In addition, this paper shows that the control system using internal information in CPG can realize the stable levitation and the disturbance suppression simultaneously. In the industry situation, the flow disturbance is not periodic because the consumption flow rate of the compressed air changes. Therefore, the band-pass filter in CPG using RIO model is redesigned to be broadband, and the disturbance can be suppressed without declining performance even when the disturbance period changes. Moreover, this paper illustrates the roles of the sigmoid function and the connection between two neurons in CPG using RIO model. When the sigmoid function is replaced with the proportion function and the saturation function, the influence is verified by experiments.