This paper presents our development of an intuitive teleoperation system for Toyota's Human Support Robot. While this robot has been widely used as an autonomous agent in the field of service ...robotics, we explore a possibility of this robot for the use of remote assistance of daily activities in home environments. For rapid prototyping an affordable teleoperation system, we adopt a commercially available VR device as a user interface and develop a Robot Operating System (ROS)-based control framework building on the software application programming interfaces (APIs). In particular, we implement a singularity robust inverse kinematics algorithm to achieve a coordinated whole-body motion of the robot for safe and intuitive operation. We empirically evaluate the practical feasibility of the proposed teleoperation system through various test tasks. We discuss the potential and limitations of the current development for its future improvement.
This paper proposes a method of formulating the robot kinematics. The proposed method can be applied to mobile manipulators, parallel link robots, and legged robots by the same procedure. The ...proposed forward kinematics formulation is based on tree-structured rigid-body system and is compared with the Denavit–Hartenberg method and URDF. The proposed differential kinematics formulation is represented by a block lower triangular matrix, which is a generalized form of the basic Jacobian matrix. In addition, an application example of the proposed formulation to the numerical inverse kinematics method is also shown. The usage of the proposed method is demonstrated by simulation experiments using a dual-arm mobile manipulator and a parallel link robot.
Legged robots must contend with challenges like load fluctuations, external forces, and modeling errors in their working environment, all of which can lead to inaccuracies in the model predictive ...control (MPC) state mapping equation. Neglecting these issues can result in deviation from the predefined trajectory, and even instability. In this article, we propose a novel MPC strategy for legged robots that enables dynamic correction of the system model and enhancing computational robustness. First, a state feedback MPC controller is proposed. Unlike prior works, we reconstruct the original nonlinear model with uncertainties as a linear model with time-varying disturbances. Subsequently, we design a closed-loop state observer to approximate the reconstructed model and employ it as the benchmark for prediction in MPC. We utilized the Lyapunov function to demonstrate that this method can ensure the ultimate uniform boundedness of state estimation errors. Second, we cascaded a whole-body controller with computational robustness as a compensatory controller for the MPC. Finally, extensive experiments on the biped robot BRAVER validated the proposed framework in both simulation and physical prototype.
In this study, an adaptive object deformability-agnostic human-robot collaborative transportation framework is presented. The proposed framework enables to combine the haptic information transferred ...through the object with the human kinematic information obtained from a motion capture system to generate reactive whole-body motions on a mobile collaborative robot. Furthermore, it allows rotating the objects in an intuitive and accurate way during co-transportation based on an algorithm that detects the human rotation intention using the torso and hand movements. First, we validate the framework with the two extremities of the object deformability range (i.e., purely rigid aluminum rod and highly deformable rope) by utilizing a mobile manipulator which consists of an Omni-directional mobile base and a collaborative robotic arm. Next, its performance is compared with an admittance controller during a co-carry task of a partially deformable object in a 12-subjects user study. Quantitative and qualitative results of this experiment show that the proposed framework can effectively handle the transportation of objects regardless of their deformability and provides intuitive assistance to human partners. Finally, we have demonstrated the potential of our framework in a different scenario, where the human and the robot co-transport a manikin using a deformable sheet. Note to Practitioners-Transportation of objects which requires the cooperation of multiple partners, is a common task in industrial settings such as factories and warehouses. The existing human-robot collaboration solutions for this task have focused only on purely rigid objects, although deformable objects need to be carried frequently in real-world applications. In this paper, we introduce a human-robot collaborative transportation framework that can handle objects with different deformability ranging from purely rigid to highly deformable. In particular, the proposed framework generates whole-body movements on a mobile collaborative robot by combining of the haptic information transmitted through the object and the human motion information obtained from a motion capture system. Moreover, the framework includes an intuitive way to rotate the object during the execution based on human hand and torso motion. The results of the experiments where objects with various deformability characteristics were transported in collaboration with a mobile manipulator demonstrated the high potential of the proposed approach in a laboratory setting. In the future, we plan to employ a less expensive vision-based human motion tracking system instead of the IMU-based system used in this study. With this change, we will be able to eliminate the need for wearable sensors from the framework presented, which would enhance its usability in real-world scenarios.
The purpose of this study was to clarify the actual situation of two-footed takeoff and landing (i.e., twofooted synchronism) during continuous two-footed hopping in young children (aged 4—5 years) ...and the effect of two-footed synchronism on spatiotemporal body control. The participants performed continuous two-footed hops for 10 blocks as quickly as possible. The total movement time required to hop 10 blocks was measured, and the participant’s hopping movement was recorded. The accomplishment rate of two-footed takeoff and landing, the flight and ground contact times, and the displacement of the trochanterion were analyzed for each hopping movement. The main results were as follows. 1. The rate of accomplishment of two-footed takeoff was higher than that of two-footed landing, and there was a significant correlation between the rates of accomplishment of two-footed takeoff and landing. 2. The ground contact time was longer than the flight time, and showed temporal variation. There was spatial variation in the anterior movement because the coefficient of variation of horizontal displacement of the trochanterion was greater than that of the vertical displacement. 3. The higher rate of accomplishment of two-footed landing was related to a shorter ground contact time, a smaller horizontal displacement, and a shorter total movement time. In particular, the accomplishment of two-footed landing was found to be the most important factor affecting quick and stable hopping. These results suggest the importance of viewing the developmental characteristics of spatiotemporal body control ability in locomotion, focusing on two-footed synchronism of the continuous twofooted hopping process.
The purpose of this study was to clarify the actual situation of two-footed takeoff and landing (i.e., twofooted synchronism) during continuous two-footed hopping in young children (aged 4—5 years) ...and the effect of two-footed synchronism on spatiotemporal body control. The participants performed continuous two-footed hops for 10 blocks as quickly as possible. The total movement time required to hop 10 blocks was measured, and the participant’s hopping movement was recorded. The accomplishment rate of two-footed takeoff and landing, the flight and ground contact times, and the displacement of the trochanterion were analyzed for each hopping movement. The main results were as follows. 1. The rate of accomplishment of two-footed takeoff was higher than that of two-footed landing, and there was a significant correlation between the rates of accomplishment of two-footed takeoff and landing. 2. The ground contact time was longer than the flight time, and showed temporal variation. There was spatial variation in the anterior movement because the coefficient of variation of horizontal displacement of the trochanterion was greater than that of the vertical displacement. 3. The higher rate of accomplishment of two-footed landing was related to a shorter ground contact time, a smaller horizontal displacement, and a shorter total movement time. In particular, the accomplishment of two-footed landing was found to be the most important factor affecting quick and stable hopping. These results suggest the importance of viewing the developmental characteristics of spatiotemporal body control ability in locomotion, focusing on two-footed synchronism of the continuous twofooted hopping process.
This paper describes the development of a dual-arm robotic system for industrial human–robot collaboration. The robot demonstrator described here possesses multiple sensor modalities for the ...monitoring of the shared human–robot workspace and is equipped with the ability for real-time collision-free dual-arm manipulation. A whole-body control framework is used as a key control element which generates a coherent output signal for the robot’s joints given the multiple controller inputs, tasks’ priorities, physical constraints, and current situation. Furthermore, sets of controller-constraints combinations of the whole-body controller constitute the basic building blocks that describe actions of a high-level action plan to be sequentially executed. In addition, the robotic system can be controlled in an intuitive manner via human gestures. These individual robotic capabilities are combined into an industrial demonstrator which is validated in a gearbox assembly station of a Volkswagen factory.
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