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The workspace and performance of a humanoid robot is decisively influenced by the design of its torso. The joints or spinal discs are usually the weak points due to the high stress they are exposed to, e. g. when lifting heavy objects. One way to circumvent the necessity of large motors is to use parallel mechanisms to optimize the distribution of loads. Here, we analyze the workspace of the humanoid...
In a cable-driven parallel robot, elastic cables are used to manipulate the end effector in the workspace. In this paper we present a dynamic analysis and system identification for the complete actuator unit of a cable robot including servo controller, winch, cable, cable force sensor and field bus communication. We establish a second-order system with dead time as an analagous model. Based on this...
The paper deals with the dynamic modeling of bio-inspired robots with soft appendages such as flying insect-like or swimming fish-like robots. In order to model such soft systems, we propose to use the Mobile Multibody System framework introduced in [1], [2], [3]. In such a framework, the robot is considered as a tree-like structure of rigid bodies where the evolution of the position of the joints...
A 2-joint, 3-link multibody vehicle model biologically inspired by a Body Caudal Fin (BCF) carangiform fish propulsion mechanism in fluid environment is presented in this paper. Under the Lighthill (LH) mathematical slender body theory different mathematical propulsive waveforms are developed to generate robotic fish locomotion. LH Cubic function is found to be 16.32 % efficient than a non-LH function...
We propose two novel human-centric force control methods for a power assist robot for lifting objects with it by the human. For this purpose, we developed a 1 DoF experimental power assist system for lifting objects. We included human's weight perception in the robot dynamics, and derived two novel force control methods for the system. We then implemented the force control methods separately. For...
The inverse dynamics model of robots is often the key for accurate control. Especially in the computed torque control, the nonlinearity and the friction can be compensated, leading to better performance. The inverse models, however, is not trivial. The traditional Euler-Lagrange model based on the rigid body assumption often underfits in the presence of frictions and requires tedious derivations;...
We propose a two-stage gait pattern generation scheme for the full-scale humanoid robots, that considers the dynamics of the system throughout the process. The fist stage is responsible for generating semi-dynamically consistent step position and step time information, while the second stage incorporated with multi-body dynamics system is responsible for generation of gait pattern that is feasible...
We utilize here regression tools to plan dynamic locomotion in the Phase Space of the robot's center of mass behavior and state feedback controllers to accomplish the desired plans. In real robotic systems, simplified locomotion models and disturbances in the control processes result in deviations from the actual closed loop dynamics with respect to the desired locomotion trajectories. To tackle these...
We address the problem of how to increase the speed of movements that occur in contact with the environment, where the initial movements were acquired by kinesthetic guiding. We take into account dynamic capabilities and constrains of both the robot and the environment. This leads to a modified, non-uniformly accelerated motion. To enable the non-uniform modulation of the movement policy, we encode...
Service robots have a great potential of improving human quality of life by aiding in everyday tasks. However, robots that share an environment and interact with humans still face some challenges that limits their acceptance. One of these challenges is how to move and behave among groups of people, which is a task performed seamlessly by humans and some animals.
In this paper, we study the scheduling architecture that enables an assembly of mobile modules to reconfigure into a humanoid formation with a manipulator arm. The investigated problem arises from the articulated nature of the formation which involves multiple degrees of freedom, thus requiring a control approach that synchronizes the actuators' motion during shape metamorphosis. Using the principles...
A novel type of mobile jack robot is proposed in view of the fact that the traditional method of debris jacking up is usually inefficient and unsafe. The jack robot has two motion modes: fast motion mode in which the robot can drive in straight line, veer and climb with the use of crawler and crawling mode in which the robot can open narrow gaps and cultivate spaces under debris by itself to enable...
This paper addresses the problem of force and position control for an unmanned coaxial rotorcraft physically interacting with its environment through contact. The proposed control strategy equips the unmanned aerial robot with the capability to safely establish contact with the surfaces of its environment and apply desired forces on them while performing sliding maneuvers. A hybrid force/position...
Light modular mechanical arm is widely used in service robots. This paper combines the SHUNCK 7 DOF mechanical arm in the application of nursing robot, building its kinematics model, analyzing the inverse kinematic problem with the geometry method against specific grasping task, and the dynamic problem with the Newton-Euler method to achieve the smooth movement of the terminal. At last, construct...
Nanosciences have recently proposed a lot of proofs of concept of innovative nanocomponents and especially nanosensors. Going from the current proofs of concept on this scale to reliable industrial systems requires the emergence of a new generation of manufacturing methods able to move, position and sort micro-nano-components. We propose to develop ‘No Weight Robots-NWR’ that use non-contact transmission...
This paper considers the question of providing effective feedback of vehicle dynamic forces to a pilot in haptic teleoperation of aerial robots. We claim that the usual state-of-the-art haptic interface, based on research motivated by robotic manipulator slaves and virtual haptic environments, does a poor job of reflecting dynamic forces of a mobile robotic vehicle to the user. This leads us to propose...
Manipulation tasks are a great challenge for robots due to the uncertainty arising from unstructured environments. In this paper we propose a novel control scheme for contact tasks based on risk-sensitive optimal feedback control. It provides a systematic approach to adjust the trade-off between motion and force control under uncertainty. Following a previously acquired task model, the proposed approach...
This paper deals with joint stiffness off-line identification with new closed loop output error method which minimizes the quadratic error between the actual motor force/torque and the simulated one. The measurement of the joint position and its derivatives are not necessary. This method called DIDIM (Direct and Inverse Dynamic Identification Models) was previously validated on rigid robots and is...
This paper presents a tool aimed at the design of compliant, under-actuated hands. The particular motivation is hands that will be used for an underwater robot to grasp a variety of objects, some of which may be delicate or slippery. The focus of the analysis is the problem of object acquisition. In comparison to many prior grasp analysis tools, the tool presented here models the dynamics of a hand,...
We present Kinodynamic RRT*, an incremental sampling-based approach for asymptotically optimal motion planning for robots with linear dynamics. Our approach extends RRT*, which was introduced for holonomic robots [10], by using a fixed-final-state-free-final-time controller that optimally connects any pair of states, where the cost function is expressed as a trade-off between the duration of a trajectory...
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