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For heavy duty tasks which are needed in field or rough terrain, we developed a hydrostatically actuated anthropomorphic hand. The hand is specifically designed for the humanoid robot HYDRA, whose 40 joints are driven by back-drivable electro-hydrostatic actuators (EHA). Each designed hand has four fingers with a total of five DOF. Each finger has three joints underactuated by one tendon. Opposition/reposition...
This paper proposes a Magneto Rheological linear clutch for use in human safe robotic applications. The force transmitted to the links of the robot must be precisely controlled for any manipulator if it has to be operated safely alongside humans. The traditional approaches to this problem is using various compliant actuating schemes like Series Elastic Actuators, Joint Torque Control etc. Research...
Use of robots is rising in process applications where robots need to interact with parts using tools. Representative examples can be cleaning, polishing, grinding, etc. These tasks can be non-repetitive in nature and the physics-based models of the task performances are unknown for new materials and tools. In order to reduce operation cost and time, the robot needs to identify and optimize the trajectory...
In this paper, we address the problem of how a robot can optimize parameters of combined interaction force/task space controllers under a success constraint in an active way. To enable the robot to explore its environment robustly, safely and without the risk of damaging anything, suitable control concepts have to be developed that enable compliant and force control in situations that are afflicted...
This paper presents the design, control, and experimental validation of a novel fully-actuated aerial robot for physically interactive tasks, named Tilt-Hex. We show how the Tilt-Hex, a tilted-propeller hexarotor is able to control the full pose (position and orientation independently) using a geometric control, and to exert a full-wrench (force and torque independently) with a rigidly attached end-effector...
In this paper we present a novel geometric approach to motion planning for constrained robot systems. This problem is notoriously hard, as classical sampling-based methods do not easily apply when motion is constrained in a zero-measure submanifold of the configuration space. Based on results on the functional controllability theory of dynamical systems, we obtain a description of the complementary...
In applications of human-robot interactions, accurate measurement of interactive forces between the human and the robot plays a significant role. Such sensors should not only be accurate and reliable, but also be soft enough to guarantee the safe and compliant human-robot interaction. In this aspect, pneumatic sensors with soft air chambers have often been utilized as a soft force measurement system...
Magnetic untethered millirobots, which are actuated and controlled by remote magnetic fields, have been proposed for medical applications due to their ability to safely pass through tissues at long ranges. For example, magnetic resonance imaging (MRI) systems with a 3–7 T constant unidirectional magnetic field and 3D gradient coils have been used to actuate magnetic robots. Such magnetically constrained...
Rigid haptic devices enable humans to physically interact with virtual environments, and the range of impedances that can be safely rendered using these rigid devices is quantified by the Z-Width metric. Series elastic actuators (SEAs) similarly modulate the impedance felt by the human operator when interacting with a robotic device, and, in particular, the robot's perceived stiffness can be controlled...
We consider the problem of grasping concave objects, i.e., objects whose surface includes regions with negative curvature. When a multifingered hand is used to restrain these objects, these areas can be advantageously used to determine grasps capable of more robustly resisting to external disturbance wrenches. We propose a new grasp quality metric specifically suited for this case, and we use it to...
This study proposes a self-locking-type expansion mechanism for in-pipe robots. Previously, we proposed a highspeed locomotion mechanism using pneumatic hollow-shaft actuators; however, this mechanism lacked holding force and could not pass through a bent pipe. The proposed mechanism generates a large holding force and can easily pass through a bent pipe by invoking a self-locking phenomenon. We conceptualize...
From being soft, flexible and producing movement by contracting, soft linear actuators are said to have musclelike properties. Due to these similarities, they are often called “artificial muscle actuator.” However, the strain produced by these actuators is generally insufficient to be utilized in a large range of applications. Some solutions have been developed, but they sacrifice force to increase...
In general, robot grasping approaches are based on the usage of multi-finger grippers. However, when large size objects need to be manipulated vacuum grippers are preferred, instead of finger based grippers. This paper aims to estimate the best picking place for a two suction cups vacuum gripper, when planar objects with an unknown size and geometry are considered. The approach is based on the estimation...
This paper mainly analyzes the typical compliant flange system and introduces impedance control methods for force tracking. First of all, we establish a compHant system with the internal cylinder of flange, electronic pressure regulator as well as other components, and build the transfer function of the system and verify the stability of the system. Next, we discuss about the model of compliant system...
In this paper, we address the problem of time-varying communication delay in force reflecting bilateral teleoperation. We introduce a switching-control method that makes the communication channel passive independent of the time-varying delay. The advantage of our approach is that we do not need information about the delay or the rate of change of the delay. Our controller results in master/slave position...
Impedance control based on robust force control can improves rehabilitation therapies. In this paper, we formulate and validate a model of a series-elastic-actuator-based ankle rehabilitation device that includes a second-order description of the human joint dynamics. In order to control the output impedance of the platform we used a cascade configuration with a PD position controller as outer loop...
This article presents the study of an optimal control problem having a non-smooth cost function and nonlinear constraints. This problem consist in the minimisation of the energy expended by a car-like vehicle or robot along a road having a known profile. The contraints are given by means of a simple model of the longitudinal dynamics. In this paper, we're interested in a particular road profile. The...
Hand rehabilitation and training systems generally utilize either robot hands or robotic gloves [1–3]. These devices generate the repetitive gripping motion of fingers. The configuration of robot hands, which consist of electrical motors, wires, gears, etc., is complex, making them difficult to wear. To avoid these problems, many researchers have been developing soft robotic gloves that utilize flexible...
Practical application of smart materials for moving robots enabled to solve difficult mechatronic positioning and movement problems. Movement in such systems is generated using piezoelectrical devices. Therefore, classical trajectories formation and control methods are not suitable. For these specific problems positioning and piezorobot control methods and algorithms are created. In order to practically...
we propose two new methods to accelerate the learning of a task using Q-learning algorithm. We focus specifically on learning of a task, which has the Credit Assignment (CA) problem. A Reinforcement Algorithm (RL) agent is performing this task in high dimensional state-space. The main idea of this paper is to use latent variables that deep autoencoders provide, to make a better rewarding system. We...
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