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In this paper, we present a new concept of multi-legged seabed robot for high tidal current environment. The robot moves on seabed by walking with 4 or 6 legs which is different moving mechanism from the existing underwater thrust system such as screw or Caterpillar. The main concept to endure the high current is utilization of hydrodynamic forces acting on the body and legs. The advantage of this...
The acrobot is an under-actuated three-joint planar robot that mimics the human acrobat who hangs from a bar and tries to swing up to a perfectly balanced upside-down position with his/her hands still on the bar. In this paper we first design the under-actuated three-joint acrobot which like human being both in actuate and appearance. And then, dynamic model is derived by Lagrange equations, and controllable...
Usually the bipedal robots use knee joints with only one degree of freedom. Several biomechanical researches have proved that the human knee joint is a complex joint with more than one degree of freedom. In the sagittal plane the human knee joint allows a rolling and a sliding of the thigh on the shin. In the case of a bipedal robot we propose a closed structure, called cross four-bar knee, which...
The single robot joint, which contains a DC torque motor and a harmonic reducer, was designed. And sliding mode control strategy by the self-adaptive adjustment of the sliding parameter ε was proposed in this paper. This control strategy can adaptively adjust ε by switching variables and their derivatives according to the system. It is applied in the control of robot joint to solve the contradiction...
This paper describes the modelling, simulation and visual servo control of a robot-arm designed for supervision of complex task environments. This robot (mini-robot) has 2 degrees of freedom (hereafter d.o.f.) and it is attached at the end of another anthropomorphic robot with 7 d.o.f. (main robot). In order to achieve a suitable supervision, the mini-robot has to perform a given trajectory around...
In this paper, we consider a novel approach to control the timing of motions when these are encoded with autonomous dynamical systems (DS). Accurate timing of motion is crucial if a robot must synchronize its movement with that of a fast moving object. In previous work of ours [1], we developed an approach to encode robot motion into DS. Such a time-independent encoding is advantageous in that it...
Tendon controlled robots with nonlinear mechanical tendon stiffness are becoming more and more popular. With the appropriate actuation, the joint position and the stiffness between motor and link side can be prescribed at the same time. In this paper, the modeling of tendon-driven elastic systems with nonlinear couplings is recapitulated. Based on the Immersion and Invariance (I&I) framework a...
This paper deals with the trajectory planning of a full-rotate parallel robot for wafer transfer operations. With the path length in work space of the robot as parameter, the dynamic model is parameterized. The system constraints-input torque and velocity constraints and the task constraints-output velocity, acceleration, and jerk limits are set; with the minimized operation time as the optimization...
This paper proposes a novel user interface for creating whole body motions of biped humanoid robots just by giving key poses. Although such an interface is popular for CG character animation, there have not been any practical systems that can appropriately handle the kinematic and dynamic conditions required for moving actual biped robots stably without falling down. In our interface, every time a...
This paper focuses on steering a 3D robot while walking on a flat surface. A hybrid feedback controller designed in for stable walking along a straight line is modified so that it is capable of adjusting the net yaw rotation of the robot over a step in order to steer the robot along paths with mild curvature. The controller is designed on the basis of a single pre-defined trajectory for periodic walking...
Zero-Moment Point (ZMP) is the most popular concept that is applied to stabilize the gait motion of a biped robot. However, the computation of the ZMP position and the dynamic model is highly complex, and so requires a considerable time. Therefore, to eliminate complex computation, this work designs a new locomotion control system for humanoid robots, which yields walking gait characteristics that...
When we have to physically interact with a robot, the benchmark for natural and efficient performance is our experience of daily interactions with other humans. This goal is still far despite significant advances in human-robot interaction. While considerable progress is made in various areas ranging from improving the hardware over safety measures to better sensor systems, the research on basic mechanisms...
Models proposed within the literature of motor control have polarised around two classes of controllers which differ in terms of controlled variables: the Force-Control Models (FCMs), based on dynamic control, and the Equilibrium-Point Models (EPMs), based on kinematic control. This paper proposes a bioinspired model which aims to exploit the strengths of the two classes of models. The model is tested...
In this study, basic research to obtain biomechanical parameters for optimized design of wearable walking assistant robot was presented and discussed in the condition of its application to the dynamic analysis of gait. Numerous studies are being conducted in order to develop intelligent walking assist devices. However, the reliability, effectiveness and durability of such intelligent walking assist...
As a stage toward a complete upper-arm motion assisted exoskeleton robot (i.e., 7DOF) this paper focused on the development of a 2DOF exoskeleton robot to rehabilitate and to ease wrist joint movements. To perform essential daily activities the movement of shoulder, elbow, and wrist play a vital role and proper functioning of the upper-limb is essential. We therefore have been developing an exoskeleton...
This paper addresses the position control of robot manipulators in general task space with a model-free controller. A simple proportional-integral-derivative (PID) control is developed. The closed-loop system formed by the proposed PID control and the robot system is shown to be global asymptotically stable. Conditions on controller gains ensuring global asymptotic stability are obtained herein in...
The shotcreting robot has 8 joints including 3 joints coupled with others on the shotcreting robot. This paper set up the Denavit-Hartenberg Frames and deduced the kinematic equations with extra three constrain equations to decouple the linked motions. The unique analytical solution of the inverse kinematic equations was educed, which provided foundation for further research on trajectory plan, dynamics...
In state of the art robotics, high positioning accuracy is achieved by using solid and stiff components as well as powerful drive units which have no backlash. In contrast, human beings are able to achieve remarkable high positioning accuracy despite of low mass, low power consumption and relatively simple mechanics. One approach to obtain this accuracy is to temporarily create additional supporting...
A new approach for adaptive torque distribution of 4-Powered Caster Vehicle (4-PCV) is presented on complex terrain without any additional sensor. The objective is that torques applied to wheels are dynamically redistributed based on the real time conditions of the whole wheel-ground interactions in order to track the desired trajectory. A novel approach based on the redundant actuated wheels is proposed...
When robots cooperate with humans it is necessary for robots to move safely on sudden impact. Joint torque sensing is vital for robots to realize safe behavior and enhance physical performance. Firstly, this paper describes a new torque sensor with linear encoders which demonstrates electro magnetic noise immunity and is unaffected temperature changes. Secondly, we propose a friction compensation...
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