Catálogo de publicaciones - libros

In this paper, we derive a kinematic model and a control law for 3D snake robots which have wheeled link mechanism. We define the redundancy controllable system and find that introduction of links without wheels makes the system redundancy controllable. Using redundancy, it becomes possible to accomplish both main objective of controlling the position and the posture of the snake robot head, and sub-objective of the singular configuration avoidance. Experiments demonstrate the effectiveness of the proposed control law.

This paper presents a simulation study of self-excited walking of a four-link biped model whose support leg is holding a bending angle at the knee. We found that the biped model with a bent knee can walk faster than the straight support leg model that has been studied so far. The convergence characteristics of the self-excited walking are shown in relation to the bent knee angle. By using standard link parameter values we investigated the effect of the bent knee angle and foot radius on walking performance. We found that the walking speed of 0.7 m/s can be achieved when the bent knee angle is 15 degrees and the foot radius is 40mm.

For research into bipedal walking machines, autonomous operation is an important issue. The key engineering problem is to keep the weight of the actuation system small enough. For our 2D prototype MIKE, we solve this problem by applying pneumatic McKibben actuators on a passive dynamic biped design. In this paper we present the design and construction of MIKE and elaborate on the most crucial subsystem, the pneumatic system. The result is a fully autonomous biped that can walk on a level floor with the same energy efficiency as a human being. We encourage the reader to view the movies of the walking results at .

This paper presents a method for energy efficient walking of a biped robot with a layered controller. The lower layer controller has a state machine for each leg. The state machine consists of four states: 1) constant torque is applied to hip and knee joints of the swing leg, 2) no torque is applied so that the swing leg can move in a ballistic manner, 3) a PD controller is used so that the certain posture can be realized at the heel contact, which enables a biped robot to walk stably, and 4) as the support leg, hip and knee joints are servoed to go back and the torque to support upper leg is applied. With this lower layer controller, the upper layer controller can search parameters that enable the robot to walk as energy efficiently as human walking without paying any attention to fall down.

Recently, Passive-Dynamic-Walking (PDW) has been noticed in the research of biped walking robots. In this paper, focusing on the entrainment phenomena which is the one of character of PDW, we provide a new control method of Quasi-Passive-Dynamic-Walking. Concretely, at first, for the sake of the continuous walking of robot and taking place of the entrainment phenomenon, we adopt a kind of PD control which gains are regulated by the state of the contact phase of swing leg. And, considering the making use of the concept of DFC, we use (-1)- trajectory of the walking robot as the reference trajectory of the step. As a result, it can be expected that the robot itself generates the optimum stable trajectory and the walking is stabilized by using this trajectory.

This article presents a model of the salamander’s locomotion controller based on nonlinear oscillators. Using numerical simulations of both the controller and of the body, we investigated different systems of coupled oscillators that can produce the typical swimming and walking gaits of the salamander. Since the exact organization of the salamander’s locomotor circuits is currently unknown, we used the numerical simulations to investigate which type of coupled-oscillator configurations could best reproduce some key aspects of salamander locomotion. We were in particular interested in (1) the ability of the controller to produce a traveling wave along the body for swimming and a standing wave for walking, and (2) the role of sensory feedback in shaping the patterns. Results show that configurations which combine global couplings from limb oscillators to body oscillators, as well as inter-limb couplings between fore- and hind-limbs come closest to salamander locomotion data. It is also demonstrated that sensory feedback could potentially play a significant role in the generation of standing waves during walking.

The nonlinear dynamics of the neuro-musculo-skeletal system and the environment play central roles for the control of human bipedal locomotion. Our neuro-musculo-skeletal model demonstrates that walking movements emerge from a global entrainment between oscillatory activity of a neural system composed of neural oscillators and a musculo-skeletal system. The attractor dynamics are responsible for the stability of locomotion when the environment changes. By linking the self-organizing mechanism for the generation of movements to the optical flow information that indicates the relationship between a moving actor and the environment, visuo-motor coordination is achieved. Our model can also be used to simulate pathological gaits due to brain disorders. Finally, a model of the development of bipedal locomotion in infants demonstrates that independent walking is acquired through a mechanism of freezing and freeing degrees of freedom.

A neuro-musuculo-skeletal model of a quadrupedal primate is constructed in order to elucidate the adaptive nature of primate locomotion by the means of simulation. The model is designed so as to spontaneously induce locomotion adaptive to environment and to its body structure, due to dynamic interaction between convergent dynamics of a recurrent neural network and passive dynamics of a body system. The simulation results show that the proposed model can generate a stepping motion natural to its body structure while maintaining its posture against an external perturbation. The proposed framework for the integrated neuro-control of posture and locomotion may be extended for understanding the adaptive mechanism of primate locomotion.

In this paper, we propose the necessary conditions for stable dynamic walking on irregular terrain in general, and we design the mechanical system and the neural system by comparing biological concepts with those necessary conditions described in physical terms. PD-controller at joints can construct the virtual spring-damper system as the visco-elasticity model of a muscle. The neural system model consists of a CPG (central pattern generator) and reflexes. A CPG receives sensory input and changes the period of its own active phase. CPGs, the motion of the virtual spring-damper system of each leg and the rolling motion of the body are mutually entrained through the rolling motion feedback to CPGs, and can generate adaptive walking. We report our experimental results of dynamic walking on terrains of medium degrees of irregularity in order to verify the effectiveness of the designed neuro-mechanical system. The motion adaptation can be integrated based on the dynamics of the coupled system constructed by the mechanical system and the neural system. MPEG footage of these experiments can be seen at: .

In this paper, we analyze the walking stability of a multi-legged locomotion robot. Based on dynamic characteristics, we propose a strategy for turning whose effectiveness is verified by numerical simulations. The robot can turn more efficiently with fewer slips after decreasing walking stability. That is, the maneuverability of the robot increases by changing the dynamic properties of the robot.