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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...
Compared with traditional rotary-percussive drills driven by electromagnetic motors, ultrasonic drills show advantages of small size, low power, low weight on bit, and lubrication free, making them available for the extraterrestrial rock sampling, especially for the minor planet with a weak gravitational field. To solve the problem that the conventional percussive ultrasonic drills cannot remove cuttings...
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 — tens of thousands of revolutions per...
Compared with traditional rotary-percussive drill driven by magnetic motors, ultrasonic drill which usually employs the high frequency longitudinal vibration of Langevin transducer to break down rocks, shows advantages of small size, low power, low axial load, and lubrication free, making it available for the extraterrestrial rock sampling, especially for the minor planet with a weak gravitational...
Biologically inspired by the hopping performance of kangaroo, this paper extends the traditional Spring-loaded Inverted Pendulum (SLIP) model by adding an actuation at hip to composite a tail-actuated SLIP (TSLIP) model as an abstract template for gait controller design. To deal with the intrinsic nonlinearity of stance dynamics in the TSLIP model, an analytical approximation is derived by virtue...
This paper presents a novel underwater localization algorithm fusing the Attitude and Heading Reference System (AHRS) with underwater altimeters to localize the underwater welding vehicles (UWV) in the spent fuel pool of the nuclear power station. The SFP is divided into multi regions according to the attitude of the UWV and the coordinate of the UWV is calculated by corresponding method in each region...
In order to verify whether a small-scale rotorcraft can fly on Mars, this paper is proposed to establish a Martian atmosphere simulator and to design a hover test stand for coaxial rotorcraft rotor. Since the ultra-low air density of Mars is approximately 1/70 of that on the Earth, it is difficult to obtain enough thrust to lift the rotorcraft against Mars gravity. The proposed Martian Atmosphere...
This paper presents a detailed experimental approach for understanding and optimizing the hover performance of Martian UAV rotor, including a systematic discussion about several coefficients for hover characteristics and a detailed design approach for rotor blades of Martian UAV at Reynolds numbers lower than 50000. The discussed hover performance coefficients include figure of merit, thrust coefficient,...
This paper presents a novel locomotion control framework that achieves stable galloping gait for a torque-controlled quadruped robot. By analytically exploiting the stance dynamics of the Spring-Loaded Inverted Pendulum (SLIP) model, a two-layered Dual-SLIP model based Task-space Formulation (DS-TSF) is developed to control the 12-DoF quadruped robot with an active spine. On the higher layer, a dead-beat...
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...
A novel active suspension of Mars rover based on six-wheeled rocker-bogie suspension is proposed and the design is given from the 2D modularization concept. The proposed suspension not only can operate as same as normal six-wheeled rocker-bogie suspension, but also provides active fold-unfold ability on the platform, great wheel-legged passing ability in soft terrain and steep slopes. The most important...
Drilling & coring has been selected as an effective method of acquiring soil sample in robotic planetary explorations. To avoid serious overload faults, drilling states should be monitored online and be tuned in a reasonable range. Herein, a novel flexible tube coring (FTC) method is adopted in China lunar exploration mission. To verify the proposed FTC method and acquire useful drilling states...
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...
Conventional ultrasonic drills can drill into rocks using high frequency axial vibration, which feature lower power and lower preload force, thus they could become a very attractive solution for future deep-space exploration. However, drill cuttings cannot be removed effectively with the increase of drilling depth by conventional ultrasonic drills that only driven by longitudinal vibration. To address...
This paper presents a methodical design of the electro-hydraulic control system for a large scale hydraulically driven six-legged robot, which can walk on rough terrain. Considering the widely varying load during the locomotion cycles, the electro-hydraulic control system should be capable of effectively handling widely varying load and possess high control bandwidth. To address these issues, a two-stage...
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 ability to open a door is essential for robots to perform home-serving and rescuing tasks. A substantial problem is to obtain the necessary parameters such as the width of the door and the length of the handle. Many researchers utilize computer vision techniques to extract the parameters automatically which lead to fine but not very stable results because of the complexity of the environment....
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...
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