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Many high-end power machines demand greater bearing performance in terms of running speed, precision, reliability, longevity, noise reduction, etc. An ultrasonic bearing based on Near-Field Acoustic Levitation (NFAL) effect is a kind of emerging noncontact gas bearing. Due to its self-aligning capability, the ultrasonic bearing can steadily run at a high speed under high precision. Actuated by piezoelectric...
In order to achieve the grasping mission in deep space, a novel and highly underactuated robotic hand which composed of bars and tendons, is proposed. The hand contains two fingers, and each finger has three joints controlled by a single motor during the grasping process. To describe the structure and the grasping properties of the of tendon-bar robotic hand, one finger is taken as research object...
Force distribution is an important problem for the legged robots with active force control, the allocation of the foot forces can also achieve a desired force and torque on the hexapod robot. This paper presents a force distribution algorithm for redundant problem reduction, linearization and reducing the internal force. Combining the distribution algorithm with force control, the robot can walk on...
This paper focuses on mechanical property of a articulated multi-unit wheel type in-pipe locomotion robot system. Through establishing the posture model of the robot system, can get the coordinates of wheel center and its corresponding contact point with pipe wall of each wheel for robot unit. Based on the posture model, the mechanical model of the robot unit is presented and the analysis is carried...
This paper deals with the interaction forces between robotic foot and the soft terrain, in conjunction with the Terzaghi theory. To date, some basic assumptions and conclusions for Terzaghi theory are analyzed. Terzaghi is recognized as a popular option to predict the bearing capacity of the terrain with upper structures. In this paper, static models in Terzaghi theory and its extended versions are...
This work was to develop a switch control approach for operating constrained mechanisms such as screwing valves or opening doors by using a rescuing mobile manipulator. The main concern is the prevention of generation of large internal forces attributed to location errors or imprecise parameter identification. Unlike conventional active or passive control methods, the proposed concept employs the...
The rescue mission of nuclear plant is both complex and dangerous, there is an urgent need to enhance the dexterity of rescuing manipulator to realize the automatic tool replacement for executing different tasks. A compliant exchanger for rescuing manipulator in nuclear plant is manufactured. The exchanger adopts a new double universal joint docking method, which can realize the compliant docking...
Sarrus mechanism and its modified configurations are widely used in space missions as one-dimensional deployable mechanisms. The degree of freedom (DOF) of the classic Sarrus mechanism is analyzed using the modified Kutzbach-Grübler criterion, which is based on screw theory. Inspired by the modified configurations, which has three branches used in high stiffness extendible and retractable mast and...
Due to the existence of clearances, contact-impact events are liable to cause lower transmission precision and slower dynamic response of the mechanism involving revolute joints. Based on the elastic-damping method, the continuous contact force (CCF) model is widely used in explicating the contact-impact phenomena. As part of storing and releasing strain energy in the CCF model, the elastic force...
It's considered as a task that a robot welds under the state of emergency and patrols daily in the nuclear reaction pool. A design scheme of underwater welding robot with cables is proposed, which move in all direction, has a function of pitching and absorb on the wall surface by thrust of propellers. In this paper in order to achieve for the precise control of the underwater robot, a dynamic equation...
Lunar soil sampling is the premise of the analysis of lunar soil and the study of lunar environment and evolutional history. Because of the restrictions of the sampling method, the size of drillers, the drilling pressure and the output power of driller, the traditional digging and vertical drilling methods can only acquire the samples from lunar surface to 3 meters deep. In order to acquire deeper...
This research proposed a pneumatic multi-pipe deep lunar soil drilling device under the background of manned lunar-landing and used coupled simulation by EDEM/Fluent for the drilled process, pneumatic drilling principle has been proved feasible by the simulation result. The drilled device this research proposed can collect lunar soil five meters under the surface, and ensure that the bedding information...
The absolute nodal coordinate formulation is suitable for the structural analysis with large rotation and deformation. The nodal coordinates include global displacement coordinates and slopes which are established in the global coordinate system without using any local coordinate, and the mass matrix is constant. In this paper, the static problem based on the absolute nodal coordinate formulation...
One of the main tasks of China's Phase III Lunar Exploration Project is to acquire lunar soil sample more than two meters deep under lunar surface and bring it back to the earth. For an essential part of drilling and sampling device, functioned as the drilling pressure providing apparatus, reasonable scheme design of the load mechanism driving unit interface guarantees the reliability of the drilling...
Gait parameters play a significant role in the locomotion of a hexapod walking robot used for different goals. Stride length and frequency are the two most important and useful gait parameters of hexapod robots. This paper presents the configuration of a hydraulic hexapod walking robot. The typical gaits of hexapod robot are introduced and the kinematic model of the robot is established. Four performance...
An underactuated robotic finger is proposed and studied for capturing non-cooperative objects, featuring an underactuated rigid-mechanism that can brake residual motion of non-cooperative targets. The finger consists of three joints driven by two actuators, and a set of one-input-two-output planetary gears is introduced to realize force transmission by using the ring gear and the planetary carrier...
Drilling & coring is considered as an effective way to acquire deep sample on the moon. Since the lunar regolith environment in depth is unknown, sampling drill should be developed to adapt to the undetermined drilling medium on the moon. Once mechanical system of sampling robot was finished, control strategy is a key to realize the high-efficiency drilling process. Since composition of lunar...
The second step for lunar exploration of China has been completed already, the probe “Chang'e-3” successfully landed on the moon, including a lander and a lunar rover. The third step of the project is to achieve automated sampling of lunar regolith through a drilling and coring device. On the moon, lunar regolith and lunar rock may be encountered randomly along the longitudinal direction. Due to the...
It is presented in this paper that a novel soil drilling sampler which can be used to drill deeply automatically in the planetary soil. There are three transmission routes of motion in the drilling sampler: rotating drive mechanism and feeding drive mechanism are used to generate the rotary and axial movement of the driller respectively while impacting drive mechanism is used to assist drilling the...
Center of mass domain of a hexapod robot must be determined in order to analyze the mobility performance and accomplish the high-fidelity simulation. Hexapod robot is simplified as a system of particles based on the structure characteristics of the developed hydraulically actuated hexapod robot. Position vectors of all mass points are established by coordinate transformation. Center of mass position...
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