(The) bipedal robot with hybrid actuation using a novel pneumatic power pack

Abstract

The study on the bipedal robot with hybrid actuation using pneumatic power pack is conducted in this paper. The pneumatic power pack development for the bipedal robot with hybrid actuation is achieved and its performance is evaluated for operating the robot. The pneumatic power pack is designed for supplying pneumatic energy to the pneumatic actuators of the bipedal robot for full mobility and disconnecting tethered pneumatic hose. Therefore, it should generate high flow rates of highly pressurized gas and it should be designed light and compact as well. The gas generation is based on the chemical decomposition of the hydrogen peroxide solution and the pneumatic power pack with pressure feedback mechanism is suggested and evaluated to make a high pressure of gas. The generated total pneumatic energy from the pack is modeled and evaluated through experiments and the modelings of monopropellant decomposition in the reactor and pressure dynamic of the reservoir. The bipedal robot with hybrid actuation based on pneumatic cylinders and electric geared motors is designed and developed. Six degrees of freedom out of total 10 degrees of freedom are active for the robot joints. Four hip joints are actuated by geared motors and pneumatic cylinders control the others at knee joints of the bipedal robot. Position-based tracking feedback controller is designed for the motor actuation and solenoid or proportional pneumatic valves are actuated to control the joints based on position sensor signals. The bipedal robot is designed with the hybrid actuation in order to verify the effectiveness of the pneumatic compliance which is powered from the proposed pneumatic power pack. The inherent compliance of pneumatics can make the robot safe from external disturbances when the robot hits the ground and make it more robust to it. The compliance model of the pneumatic cylinder is suggested and taken into account for the robot balancing control. The developed pneumatic power pack is designed for implementing the bipedal robot. The dual reactor is adopted for generating enough gas flow rates for operating the robot. The gas generating performance is evaluated for the robot operating conditions. The suggested pneumatic circuit performance of the power pack such as initial pressure acceleration and reverse flow allowance are evaluated through simulations and experiments.