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In this paper, stable hopping of a one-legged, articulated robot with a flat foot is investigated. The robot has a special feature that before taking off, it goes through an underactuated phase in which the foot rotates about the unactuated toe on the ground. By having the underactuated phase, the robot can perform stable human-like hops with longer hopping distances. To devise a systematic trajectory...
We present a control architecture for fast quadruped locomotion over rough terrain. We approach the problem by decomposing it into many sub-systems, in which we apply state-of-the-art learning, planning, optimization and control techniques to achieve robust, fast locomotion. Unique features of our control strategy include: (1) a system that learns optimal foothold choices from expert demonstration...
This paper proposes a reactive motion controller for a humanoid robot to maintain balance against a large disturbance, by relatively stepping. A reactive step is performed by the robot, so that it reduces the disturbance force. Several problems are addressed: first the motion is designed to ensure the respect of stepping constraints such as a dynamical stability, motion feasibility of the swing leg...
The work presented in this paper deals with the generation of trajectories for humanoid robots imitating human gaits captured with a motion capture system. Once the human motion is recorded, this one is modified to be adapted to the robot morphology. The proposed method could be used for human-like robots of different sizes and masses. The generated gaits are closed to the humans ones while respecting...
The this work deals with neural network-based gait-pattern adaptation algorithms for an active lower limbs orthosis. Stable trajectories are generated during the optimization process, considering a stable trajectory generator based on the Zero Moment Point criterion and the inverse dynamic model. Additionally, two neural network (NN) are used to decrease the time-consuming computation of the model...
Parametric excitation walking is one of methods that realize a passive dynamic like walking on the level ground. In parametric excitation walking, up-and-down motion of the center of mass restores mechanical energy and sustainable gait is generated. Walking ability and walking performance strongly depend on the reference trajectory of the center of mass. In this paper, we propose an optimization method...
In this paper, a humanoid is simulated and implemented to walk up and down a staircase using the blending polynomial and univariate dynamic encoding algorithm for searches (uDEAS). The motivation of this paper is to divide efficient walking step for a commercial humanoid when ascending and descending a stair. Therefore ascending and descending a staircase are each scheduled by four steps. Each step...
It is a difficult task to create a realistic human animation because of the high complexity of human motion. To address this problem, a new method is presented for producing physically valid motion with example motions. The core of our method is physics-based space-time optimization (PBSO). PBSO introduces physical constraints into conventional space-time optimization and then ensure the physical...
We consider the task of planning smooth trajectories for robot motion. In this paper we make two contributions. First we present a method for cubic spline optimization; this technique lets us simultaneously plan optimal task-space trajectories and fit cubic splines to the trajectories, while obeying many of the same constraints imposed by a typical motion planning algorithm. The method uses convex...
The purpose of this study is to develop a methodology that enables a humanoid robot to imitate a whole body motion of a human. In the communication and interaction with a human being with motions and gestures, a humanoid robot needs not only to look like a human but to behave as a human does to make sure the meanings of motions and gestures. To act like a human, the humanoid robot has to imitate the...
Multiple strategies for standing balance have been observed in humans, including using the ankles to apply torque to the ground, using the hips and/or arms to generate horizontal ground forces, and using the knees and hips to squat. This paper shows that multiple strategies can arise from the same optimization criterion. It is likely that humanoid robots will exhibit the same balance strategies as...
We present a method to optimize the walking pattern of a humanoid robot for forward speed using suitable metaheuristics. Our starting point is a hand-tuned open-loop gait that we enhance with two feedback control mechanisms. First, we employ a P-controller that regulates the foot angle in order to reduce angular velocity of the robot's body. Second, we introduce a phase resetting mechanism that starts...
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