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Optical motion capture systems, which are used in broad fields of research, are costly; they need large installation space and calibrations. Applying this technology in typical homes and care centers is unrealistic. Low cost motion capture systems such as Microsoft Kinect are based on video, thus privacy issues might arise from their usage. Therefore we propose to use low cost contact force measurement...
Here we present a suite of theoretical, computational, and experimental studies culminating in the first aerial and aquatic capable insect-scale robot. We develop a computational fluid dynamics (CFD) simulation to model fluid-wing interaction in air and water. From CFD and a system dynamics analysis we predict that a multi-modal flapping strategy will enable locomotion in both air and water for a...
Touch trigger probes are most widely used on coordinate measuring machines (CMM) and machine tools. Due to the tripod structure, pretravel of the probe varies when it triggers in different directions, which has been acknowledged as a key error source resulting in large measurement uncertainty. Return mechanism is one of the key factors affecting the probes' pretravel variation and repeatability. Currently,...
This paper presents a recursive and parallel formulation for the dynamics simulation of large articulated robotic systems based on the Hamilton's canonical equations. Although Hamilton's canonical equations exhibit many advantageous features compared to their acceleration based counterparts, it appears that there is a lack of dedicated parallel algorithms for multi-rigid body dynamics simulation based...
Pelvic motion plays an important role in human locomotion. Any abnormality of the pelvic motion during walking, such as asymmetry or altered range of motion, can affect gait stability and energy consumption [1]. In this work, we propose a new control methodology to guide and correct the human pelvic motion in the transverse plane during walking. An assist-as-needed paradigm was used to generate forces...
Force feedback controller (haptic device) is the key part of a master-slave tele-operation system. It can transmit its position, orientation and velocity to remotely operate the controlled object; at the same time it can acquire information of force/torque from the remote object, and rebuild those to the operator by enabling a force sense telepresence. In this paper, a new type force feedback controller...
This paper mainly deals with the maneuverability capabilities of the propeller-fin-driven underwater vehicle. The nonlinear dynamic model is firstly set up, numerical simulations of kinematic behaviors in the horizontal plane, vertical plane and three-dimensional space are performed respectively to verify the nonlinear dynamic model. Then, Z-shaped steering method with a positive and identical negative...
This paper presents a new theoretical control approach for the feedback stabilization of a class of mechanical systems with impulse effects that is based on using Lyapunov conditions of asymptotic stability as kinematic affine constraints [8] where the corresponding constraint force is the control force. We prove that the condition of existence and uniqueness lead to a system of partial differential...
Exoskeletons have been used successfully for functional training of human motions. Our designs of the Cable-driven Arm Exoskeleton (CAREX) are targeted to improve arm function in patients with stroke. In this study, we focus on how muscle activation patterns of subjects change during movements with and without CAREX. Our goal was to evaluate whether CAREX distorts the natural pattern of EMG activity...
Presenting a mathematical modeling method for the electro-hydraulic actuation systems utilizing a common actuator with multi degree tree-like kinematic structure. The method allows to consider the impact of external forces, force strikes and imposed inter connections on the mechanism in motion. Differs from the known applying methods by more compact and transparent presentation of the basic equations...
Powered exoskeletons can provide motion enhancement for both healthy and physically challenged people. Compared with lower limb exoskeletons, upper limb exoskeletons are required to have multiple degrees-of-freedom and can still produce sufficient augmentation force. Designs using serial mechanisms usually result in complicated and bulky exoskeletons that prevent themselves from being wearable. This...
In this paper, nonlinear controllers are designed for an accurate path-following of a track vehicle towing an active implement, which is steered and driven, in off-road terrains like farms where longitudinal and lateral slips at front tracks and rear steerable wheels are inevitable. These controllers are based on path offset values and a partial dynamic model. The controller is designed to minimize...
In the paper the skid-steering mobile platform has been considered. Such object should be treated as an underactuated system. Artificial force method has been used as a solution for controlling an underactuated system on the dynamic level. The paper presents the influence of different methods of modeling, based on artificial force method, on the system's behavior, especially on control signals.
Wearable technologies are gaining great popularity in the recent years. The demand for devices that are lightweight and compact challenges researchers to pursue innovative solutions to make existing technologies more portable and wearable. In this paper we present a novel wearable cutaneous fingertip device with 3 degrees of freedom. It is composed of two parallel platforms: the upper body is fixed...
Front end loader are commonly used in agriculture machinery. A special feature of the loader is the parallel positioning of the bucket while lifting the boom. Modeling of the hydraulic, kinetic and kinematic behavior of the front end loader is helpful for the design of a controller for parallel positioning. In this paper we describe the mathematical background of this model. The model considers the...
Pseudo haptic sensation is an illusion based on visual stimuli. In virtual environments the principle of pseudo haptic feedback is used to simulate material properties such as stiffness, mass and friction. Transfering the principle of pseudo haptic feedback to real haptic teleoperation systems can provide a haptic sensation for properties of material, manipulated without active haptic feedback. Hence,...
This paper presents a method to transfer functional grasps among objects of the same category through contact warping and local replanning. The method transfers implicit knowledge that enables an action on a class of objects for which no explicit grasp or task information has been given in advance. Contact points on the source object are warped based on global and local shape similarities to the target...
We consider in this paper cable driven parallel robot (CDPR) with m catenary cables that present a significant deformation due to their elasticity and own mass and we address the kinematics of such a robot under the assumption of static state. We show that the inverse kinematics (IK) requires to solve a square system of equations if the robot has up to 6 cables and an underconstrained system if m...
Actuators with adjustable transmission ratios are required in a variety of robotics and automation applications, spanning from human assistive devices and mobile robots to general manipulators. Most existing self-adjustable actuators are bulky and mechanically complex, which often makes their implementation challenging. In this work, we propose a novel passively-adjustable transmission mechanism based...
Kinesthetic teaching is a promising approach to acquire robot skills in an intuitive way. This paper focuses on learning skills that do not solely rely on kinematics but also need to take into account interaction forces. We present three novel concepts towards learning such force interaction skills. Firstly, we determine segments from a small number of continuous kinesthetic demonstrations using contact...
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