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This paper presents a decentralized optimal control method for modular and reconfigurable robots (MRRs) based on adaptive dynamic programming. First, the dynamic model of MRRs is formulated by using the Newton-Euler iterative algorithm, and then the state space description is given. Second, the optimal control policy of the MRRs system is obtained based on the policy iteration algorithm, which is...
Based on the working principle of the electrohydraulic proportional control system of the working device of the demolition robot, the co-simulation model of the system is established by means of ADAMS and MATLAB. The study of the dynamic characteristics of the system was done, with applying traditional PID control strategy and sliding mode variable structure control respectively, considering the change...
The research on heart cells have attracted broad attention for the development of either heart disease therapy or muscle cell-based actuation for bio-syncretic robots. In order to study the mechanism and dynamics of beating activity of cardiomyocytes, many research methods have been proposed, such as the measurement of contractility and action potential of the cells. However, few of them has focused...
Controlled independent manipulation of multiple objects at cellular length scales in an open challenge with potential applications in life sciences and advanced manufacturing. Magnetism has been studied as a means to perform such fine scale manipulation, but generating fields that discriminate between targets at small length scales is nontrivial. We present a system for simultaneous control of multiple...
Teleoperation is a human control system enabling humans to interact with the remote environment through a dual robot system which includes a master robot and a slave robot operating in two different places. Wave variables and scattering approaches were proposed in [1],[2] with constant time delay, [3],[4] with varying time delays. This paper develops them based on different wave variables and new...
This paper presents a novel method— asymmetric dual-user shared control method and makes a proof of the stability conditions of the novel method with time delay. Firstly, we model the novel dual-user shared control architecture with multi-dominance factors, considering the influence between the slave and masters respectively. Then, the system is divided into three paralleling subsystems, and the system...
In this paper, we present the design, fabrication and the function of a soft actuator embedded with Low-Melting-Point Alloy (LMPA). By melting the metal via joule heating, the phase of the metal transformed from the solid state to the liquid state, by which the stiffness of the actuator changed over nearly an order of magnitude. Through a reheating-recrystallizing circle, the actuator can self-healing...
A series elastic actuator (SEA) consists of an actuator in series with a compliant element. By measuring and controlling the displacement of the compliant element, an SEA provides better forward and inverse force control accuracy than traditional stiff actuators. SEAs are suitable for robots that need interact properly with human or environment. Most SEAs use brushless DC motors as the actuators....
We describe the concept and first prototype of a novel mechatronic design of a robotic gripper, which aims at being mounted on a humanoid robot to achieve firm (i.e. locked) and robust grasps. Such grasps could ideally support complex multi-contact motions, such as ladder climbing, or manipulation of complex tools, with energy efficiency. For this purpose, we propose a solution by designing a smart...
Physical human-robot interaction is one of the hottest topic in robotics and safety issues are its fundamental aspect. The present paper contributes to this aspect in that collision detections can be completed on the servo level in an intuitive way. The principle of the proposed collision detection strategy is based on the relative difference of the feedback commanded torque, which is able to identify...
In this study, we developed a wall-climbing robot for airplane body inspection. To move on airplane body, the robot needs to move on walls and curved surfaces. A traveling-wave-type, omnidirectional wall-climbing robot that uses magnetic force to adhere could move on such a wall and curved surface. However, magnetic force cannot be used to adhere to airplane body. Therefore, we developed a wall-climbing...
The authors showed that an underactuated locomotion robot can generate a stable forward motion on downhill by utilizing the effects of sliding and wobbling. It was, however, difficult to generate forward motion on level surface. Our next research objective is therefore achieving stable motion generation on slippery level surface. It is being developed that a new type of the robot utilizing wobbling...
In this paper, we present the control of and experimentation on an active dual-mode twisted string actuation mechanism for automatic transmission. This mechanism has a two-stage transmission ratio and is implemented by changing the twisted radius of the string in each mode (force mode or speed mode). Control algorithms for implementing different transmission ratios are proposed and experimentally...
While there has been recent success with robotic therapy approaches, individual differences in motor impairments motivate the need for customized therapy. Our latest work with healthy participants considered the likelihood of one's error to construct a customized force field training environment, which we termed an error field. We believe error statistics could characterize individual motor impairments...
In this work, a surface skin electromyography(sEMG)-based control solution for elbow wearable assistive devices during load lifting tasks is presented. The goal of the controller consists in limiting the user's muscle activity during the task execution, in such a way that the assistive device can partially compensate the load-related biceps muscle effort. Since sEMG-driven control strategies based...
This paper presents two mechanisms to enable jumping microrobots. These small jumpers must store considerable mechanical energy and quickly release it. The first mechanism presented is a mechanical gain stage capable of amplifying the force generated by a standard inchworm motor by at least 10 times. This mechanism could be used with any style of inchworm motor. Secondly, a latching mechanism was...
The article focuses on designed construction of the exoskeleton, which significantly reproduces the kinematic structure and the range of joint movement of the human upper limb. The exoskeleton will able to control real objects i.e. loading crane, including force feedback. The designed device, composed of seven rotary joints, is equipped with the closed loop Bowden cable conduit system with linear...
This paper proposes a novel technique for the real-time estimation of the joint torques variations in humans while performing heavy manipulation tasks. To achieve this, the method is based on the deviations of the Centre of Pressure (CoP) and Ground Reaction Force (GRF) in the presence of interaction forces. The CoP and GRF variations are calculated from the difference between the estimated values...
This paper presents the design, mathematical model, and evaluation of a novel variant of a variable stiffness actuator. The actuator combines a cam and a variable lever mechanism. The lever length changes through the rotation of the follower and results in the change of the mechanism stiffness. The design of the actuator results in a nearly linear torque-deflection characteristic, earning it its name:...
In recent years, ventilation equipment has been installed in various structures to draw in outdoor air and circulate indoor air. These ventilation installations have pipes (ducts) through which air flows. If dust accumulates in a duct, it will be carried indoors by the airflow. Dust adversely affects human health, and so these ducts must be cleaned regularly. However, the existing cleaning methods...
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