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In this study, a deformation control with spatial decoupling properties is designed and implemented. This control strategy treats the shift in position and posture attributable to an external force as the deformation of the robot. The deformation dynamics are constructed from the Maxwell and Voigt models, which describe plastic and elastic deformation, respectively. Next, a control method is proposed...
In this paper, an asymmetric cable-driven mechanism is proposed for accurate force control of exoskeleton systems with a compact structure. Inspired by the fact that the required forces in human motions are not symmetric in many cases, a spring-actuator type cable-drive mechanism is adopted, which enables a compact cable routing structure. The joint is connected with the exoskeleton frame through...
In most 6 DOF robot arms, considerable amounts of gravitational torques due to the robot's own weight are applied to pitch joints of the robot, which causes most arms to use high capacity motors and speed reducers. A spring-based counterbalance mechanism can compensate for this gravitational torque, thus leading to a significant reduction in the effect of gravity. However, a simple installation of...
In this paper we present the design and characterization of a novel Passive Variable Stiffness Joint (pVSJ). pVSJ is the proof of concept of a passive revolute joint with controllable variable stiffness. The current design is intended to be a bench-test for future development towards applications in haptic teleoperation purposed exoskeletons. The main feature of the pVSJ is its capability of varying...
The bad controllability of pulmonary mechanism was found during the electronic regulator design, and showed up as the sound of snore along with breathing. The experiment for simplified pulmonary mechanism was carried out and defined that the force unbalance point exists in the pulmonary mechanism. The schematic and working principle of the electronic regulator are shown in the paper. Then the FLUENT...
This paper presents a multilink-articulated robot with omni and hemispherical wheels (AIRo-II) for inspecting and exploring winding pipes. To quickly adapt to winding pipes, holonomic rolling movement without moving forward and backward is more useful. However, this requires the replacement of driving actuators with rolling actuators at the expense of the driving force. In this paper, we investigate...
We propose a novel variable stiffness joint (VSJ) mechanism that achieves the desired stiffness by using elastic deformation of silicone rubber cushions (SRCs). This mechanism can absorb the forces from multiple direction by the flexibility of SRCs and guarantee high safety. To react adequately against unpredictable collision or to manipulate an unstable object skillfully, a joint should be designed...
We present a new palm design that features a dense array of micro-spines for the JPL Robosimian human-scale climbing robot. A linearly-constrained spine mechanism is introduced and analyzed using adhesion and stiffness models. This mechanism achieves a spine density of 19/cm2 and a mean adhesion of 67N (207kPa) on coarse concrete surfaces. The models are validated on two different surfaces with two...
The majority of recent researches have been focused on developing compliant joint for rotary motion. Few authors contributed to the problematic of safety in pure linear motion, i.e. prismatic joint. The contribution of this work is to present a new design capable of achieving, passively, a nonlinear elastic behavior for prismatic joint implementation, the so-called Prismatic Compliant Joint (PCJ)...
Linear oscillating motor attracts considerable focus in industrial applications due to its high efficiency and power density. Despite it has maximum efficiency on its resonant frequency, achieving accurate resonant frequency recognition and tracking is difficult, especially under complicated hydraulic load. In this paper, a novel resonant frequency recognition and tracking strategy is proposed for...
Since the characteristics of the servo valve's spool valve pair are difficult to grasp, this paper proposes methods of testing the internal characteristics parameters of the spool pair under variable temperature conditions. Based on these methods, a series of testing systems are designed and test platforms are built, which can measure the viscous damping coefficient, coulomb friction, hydrodynamic...
Fire is one of the fatal threats in manned spacecraft, water mist fire suppression technology has become one of the most important methods to preventing fires. As the main motive components, high pressure water hydraulic piston pump is very important for the development of water mist fire suppression technology. A novel crankshaft piston pump was studied through simulations and experiments in this...
In this study, design of a new robotic mechanism for traversing low diameter pipelines has been addressed. Pipe inspection, especially low diameter kind, for detecting defects has always gathered much interest for researchers in medical or industrial applications. Using a mechanism which move successfully into pipes with different diameters, with an appropriate adaptability while passing complex routes...
This paper proposes design of a weight measurement system capable of measuring weight in the range of micrograms to milligrams. The configuration of the system resembles with a conventional straw balance. Unlike straw balance the proposed system employs a force overcome technique. It does not employ any spring as that in case of other types of electromagnetic balance and any vibrating element present...
Accurate and precise control of catheters inside a vasculature is a difficult yet important task. Current manual approaches require significant surgical skill. Over the years, surgeons build up a sort of mental kinematic map telling them how to handle the catheter in order to steer the catheter tip safely through the vessel system. The input-output behaviour of the catheter is complex and depends...
In order to provide highly compliant and powerful force, a series elastic actuator (SEA) has been developed and are now widely utilized. In spite of this characteristics as an ideal force source for safe human-robot interactions, SEA is considered difficult to design and control as its mechanical structure is complicated, namely it consists of a motor, a reduction gear, an elastic element and load,...
The design, fabrication and testing of a novel electro-thermal linear motor is presented in this paper. The V-shape electro-thermal actuator arrays, micro lever, micro spring and slider are introduced. In moving operation, the linear motor can move 1 mm displacement while keeping the applied voltage as low as 17 V. In holding operation, the motor can stay in one particular position without consuming...
Our recent work on Wave Energy Converters (WEC) introduced the ideas of a Linear Sliding WEC (LS-WEC) and an electromechanical spring, or eSpring, to dynamically control system forces and maintain resonance conditions during changing wave conditions. In that work, we assumed that the LS-WEC contained a sliding translator mass that moved on a linear track in response to buoy pitch and roll in a dynamic...
Based on the characters of repulsive force actuator for its fast speed in the opening and closing process, a kind of new-type fast circuit breaker energized by fault current was designed in this paper. With bus shunt as excitation current, double coil tandem repulsive force actuator and permanent magnetic actuator were composed together. This hybrid circuit breaker with new-type of excitation doesn't...
The working performance of high voltage circuit breakers is with great importance for the security of power grid. In this paper, a kind of permanent magnet operating mechanism was modeled and studied. The simulation model was verified by experiments. The opening and closing process is divided into three stages according to its force analysis, respectively. The angle displacement of main axis is related...
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