The purpose of this study is the development of a valve that can precisely control pneumatic cylinders. The valve is lightweight and has simple structure. The valve uses a piezoelectric oscillator which is driven in the resonance mode, and it can control flow rate by controlling the amplitude of the particle excitation. In this report, we have designed a new prototype for the purpose of high controllability. We have applied a non-linear control algorithm to control Q-V nonlinearlity of this valve. We found that this control works well to realize linear Q-V characteristics.

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This paper proposes a new type of compressor that can discharge air in alternate directions. This compressor can operate the direction/speed of a cylinder by changing the clockwise/counterclockwise rotational direction and the rotational speed of the compressor, and also does not need additional solenoid control valves. The key issue here is to develop an alternate direction air compressor having effective performance. In this report, we verify the fundamental characteristics and advantages of this compressor. We also investigate the possibility a cylinder system using this new type of compressor.

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We develop a quadruped walking robot, assuming human cooperative tasks in construction building or rescue activity in disaster environment. Pneumatic cylinders are employed as driving actuators since they have explosion proof and inherent compliance. Owing to the compliance feature, external force is easily estimated based on the inner pressure of the cylinder. We provided a compliance control system on each leg based on the estimated floor reaction force with disturbance observer. After giving an overview of the developed quadruped walking robot, we describe the kinematics, statics and control system of each leg. We propose a motion control strategy based on the floor reaction force estimated using a disturbance observer. The validity of the proposed control system is verified through some experiments.

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