A dynamic biped locomotion robot which realizes high speed movement is presented. Its walking cycle is about 0.45 s, its speed is about 0.8m/s, and its appearance resembles a human walking. A hierarchical control structure is adopted at the lower level at which the local feedback is implemented. The reference signal to each local controller is supplied from its higher level. The stability of steady walking is examined by using the reduced order model which has been derived by the authors and it is assured by experiments.
We aimed to realize smooth 3D biped walking in a robot through control based on information obtained from various sensors. We employed a method to control walking by divid ing it into motions in the sagittal plane and in the lateral plane. We treated motion in the lateral plane as a regulator prob lem with two equilibrium states. We also used relatively low gain feedback coefficients obtained from the optimal regula tor theory. For motion in the sagittal plane, we put the body speed close to the smooth speed function given in advance by controlling the ankle torque. The effectiveness of the proposed control method was ex amined by computer simulation and proved by experiments with our BLR-G2 walking robot. The BLR-G2 is equipped with foot pressure and ankle torque sensors to provide infor mation about the condition of contact with the floor. The sole and ankle driving actuators undergo force/torgue feedback control based on the sensor information. These contributed toward realizing smooth walking with the sole firmly gripping the floor.
Magnetorheological (MR) fluids are materials that change their rheological behavior upon applying a magnetic field. They have been promising as functional fluids that can improve the properties of mechanical systems. We have developed an actuator using MR fluid. In the previous paper, a method of designing MR-fluid actuators was proposed on the basis of magnetic circuit theory. The basic experiments were carried out and static properties that agreed well with the design were obtained. However, the transient response, which was not considered in the design phase, was not very fast. In this study, we investigate the dynamics of the MR-fluid actuator and aim to improve the response. The transient magnetic analysis is examined in consideration of the eddy current. Two approaches to improving the response are proposed. Finally, we realize a much faster MR-fluid actuator.
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