The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
In this paper, previous works on the Model Predictive Control (MPC) and the Divergent Component of Motion (DCM) for bipedal walking control are extended. To this end, we employ a single MPC which uses a combination of Center of Pressure (CoP) manipulation, step adjustment, and Centroidal Moment Pivot (CMP) modulation to design a robust walking controller. Furthermore, we exploit the concept of time-varying...
This paper discusses the resolved viscoelasticity control (RVC) method that explicitly considers the structure-variability for a humanoid. In a previous report, the author proposed resolving the virtual viscoelasticity at the center of gravity into the joint viscoelasticity considering redundant degrees of freedom, and named this method as RVC. However, the author considered only the single support...
This paper proposes an approximate-kinetic-model-based self-adaptive (AKS) control system to rapidly generate target walking speed by an underactuated compasslike bipedal walker. First, a model of the underactuated compass-like bipedal walker is built, and an open-loop system is introduced and analysed as the prototype of AKS system. Second, the control law of AKS is described in detail. The dynamic...
This work introduces a novel hybrid control architecture for a hexapod platform (Weaver), making it capable of autonomously navigating in uneven terrain. The main contribution stems from the use of vision-based exteroceptive terrain perception to adapt the robot's locomotion parameters. Avoiding computationally expensive path planning for the individual foot tips, the adaptation controller enables...
Quadrupedal locomotion can be described as a constrained optimization problem that is very hard to solve due to the high dimensional, nonlinear and non-smooth system dynamics. In this paper, we propose a formulation that can be solved within few seconds using sequential quadratic programming. This method considers only a simplified model that just sufficiently represents the system dynamics. The output...
Affected by distance, interference, and passenger flow, escalators or staircases that are closer to the transfer station are being selected by more and more people, resulting in an unbalanced distribution of passenger flow and congestion. During rush hour, if passengers who use an escalator stand on only one side of the escalator, then passengers for different trains are prone to huddle together....
The ability to accurately predict human motion is imperative for any human-robot interaction application in which the human and robot interact in close proximity to one another. Although a variety of human motion prediction approaches have already been developed, they are often designed for specific types of tasks or motions, and thus do not generalize well. Furthermore, it is not always obvious which...
This paper presents an off-board trajectory controller for a range of stride frequencies (2–45 Hz) that enables zero-radius turns and holonomic control on one of the smallest and fastest legged robots, the Harvard Ambulatory MicroRobot (HAMR). An experimental model is used as the basis for control to capture the highly nonlinear response of the robot to input signals. Closed-loop trajectories are...
When limbs are decoupled, we find that trajectory outcomes in mechanical systems subject to unilateral constraints vary differentiably with respect to initial conditions, even as the contact mode sequence varies.
This paper presents a novel locomotion control framework that achieves stable galloping gait for a torque-controlled quadruped robot. By analytically exploiting the stance dynamics of the Spring-Loaded Inverted Pendulum (SLIP) model, a two-layered Dual-SLIP model based Task-space Formulation (DS-TSF) is developed to control the 12-DoF quadruped robot with an active spine. On the higher layer, a dead-beat...
We present an algorithm that generates walking motions for quadruped robots without the use of an explicit footstep planner by simultaneously optimizing over both the Center of Mass (CoM) trajectory and the footholds. Feasibility is achieved by imposing stability constraints on the CoM related to the Zero Moment Point and explicitly enforcing kinematic constraints between the footholds and the CoM...
Autonomous legged robots will be required to handle a wide range of tasks in complex environments. While a lot of research has focused on developing their abilities for periodic locomotion tasks, less effort has been invested in devising generalized strategies for dynamic, non-periodic movements. Motion design approaches are frequently enlisted in the form of teleoperation or predefined heuristics...
This paper presents, compares, and experimentally implements two robust model-based controllers for transfemoral prosthetic walking: the robust passivity (RP) controller and the robust sliding mode (RS) controller. These findings constitute the first steps toward using model-based controllers for prosthetic devices as an alternative to commonly-used variable impedance and proportional-derivative (PD)...
In this paper we propose an enhancement to our previous Conditional Random Field (CRF) based map matching algorithm in order to make the map matched trajectory smoother and more feasible. The existing algorithm uses one feature, which is the distance with the input coordinate, and has the problem of non-smooth output trajectory. In this work we propose adding a new semantic layer to the map model...
The evolution of smartphones and their embedded sensors motivates research toward the development of handheld device based navigation solutions especially for harsh environments. In this context, Pedestrian Dead Reckoning is usually adopted to compute the pedestrian's trajectory. Step/stride lengths and walking directions are combined in a recursive process. Unfortunately the estimated path suffers...
The Underactuated Lightweight Tensegrity Robotic Assistive Spine (ULTRA Spine) project is an ongoing effort to develop a flexible, actuated backbone for quadruped robots. In this work, model-predictive control is used to track a trajectory in the robot's state space, in simulation. This is the first work that tracks an arbitrary trajectory, in closed-loop, in the state space of a spine-like tensegrity...
This paper work addresses the enhancement of this technique by associating it the polar coordinates as a proposed tool for a better detection and location of the faulty inverter switch. The proposed use of the polar coordinates tool not only allows the exact computation of both the magnitude and the phase angle values of the fault current vector allied to the faulty inverter IGBT but also enables...
Bipedal humanoid robots have complex dynamics and they are intrinsically unstable. Although, bipedal robots have a similar kinematic architecture to a human and they are the most appropriate type of robots to operate in human environments, developing a humanoid robot that has robust is a difficult task. This paper proposes an omnidirectional walking engine that takes into account the push recovery...
Hexapod legged robot's missions, particularly in irregular and dangerous areas, require high stability and high precision. In this paper, we consider the rectangular architecture body of legged robots with six legs distributed symmetrically along two sides, each leg contains three degrees of freedom for greater mobility. The aim of this work is planning tripod gait trajectory, based on the computing...
As legged robots maneuver over increasingly complex and rough terrains, designing motion planners with the capability of predicting future footsteps becomes imperative. In turn, these planners provide a valuable tool for understanding the fundamental principles underlying human locomotion [2, 3]. In this study, we use our previously proposed phase-space planning framework [1] to analyze human walking...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.