Proposal of Walking to Prevent a Fall of a Planetary Exploration Legged Rover Using Effect of Loose Soil Caused by a Propagation of Vibration

In this study,a walking method that prevents a fall of the planetary exploration-legged rover is proposed.In the proposed walking method,the leg is sunk by giving vibration to the ground.The posture of the rover is changed to prevent a fall of the rover by sinking the leg.First,the relationship between the kind of vibration and the subsidence of the leg is confirmed.In this experimental result,the leg is shown to be easy to sink to the ground by giving vibration.Moreover,the larger the vibratory force is,the easier the leg sinks to the ground.Finally,the legged testbed walks on the loose ground with a slope using the proposed walking method.In this experimental result,the testbed is difficult to fall down when it uses the proposed walking.Moreover,the angle of a slope that the testbed can walk becomes large by using the proposed walking.

High-adaption locomotion with stable robot body for planetary exploration robot carrying potential instruments on unstructured terrain

There is a strong demand for Planetary Exploration Mobile robots(PEMRs)that have the capability of the traversability,stability,efficiency and high load while tackling the specialized tasks on planet surface.In this paper,an electric parallel wheel-legged hexapod robot which has high-adaption locomotion on the unstructured terrain is presented.Also,the hybrid control framework,which enables robot to stably carry the heavy loads as well as to traverse the uneven terrain by utilizing both legged and wheeled locomotion,is also proposed.Based on this framework,robot controls the multiple DOF leg for performing high-adaption locomotion to negotiate obstacles via Gait Generator(GG).Additionally,by using Whole-Body Control(WBC)of framework,robot has the capability of flexibly accommodating the uneven terrain by Attitude Control(AC)kinematically adjusting the length of legs like an active suspension system,and by Force/torque Balance Control(FBC)equally distributing the Ground Reaction Force(GRF)to maintain a stable body.The simulation and experiment are employed to validate the proposed framework with the physical system in the planetary analog environments.Particularly,to smoothly demonstrate the performance of robot transporting heavy loads,the experiment of carrying 3-person load of about 240 kg is deployed.

Three-layer intelligence of planetary exploration wheeled mobile robots:Robint,virtint,and humint

The great success of the Sojourner rover in the Mars Pathfinder mission set off a global upsurge of planetary exploration with autonomous wheeled mobile robots(WMRs),or rovers.Planetary WMRs are among the most intelligent space systems that combine robotic intelligence(robint),virtual intelligence(virtint),and human intelligence(humint) synergetically.This article extends the architecture of the three-layer intelligence stemming from successful Mars rovers and related technologies in order to support the R&D of future tele-operated robotic systems.Double-layer human-machine interfaces are suggested to support the integration of humint from scientists and engineers through supervisory(Mars rovers) or three-dimensional(3D) predictive direct tele-operation(lunar rovers).The concept of multilevel autonomy to realize robint,in particular,the Coupled-Layer Architecture for Robotic Autonomy developed for Mars rovers,is introduced.The challenging issues of intelligent perception(proprioception and exteroception),navigation,and motion control of rovers are discussed,where the terrains' mechanical properties and wheel-terrain interaction mechanics are considered to be key.Double-level virtual simulation architecture to realize virtint is proposed.Key technologies of virtint are summarized:virtual planetary terrain modeling,virtual intelligent rover,and wheel-terrain interaction mechanics.This generalized three-layer intelligence framework is also applicable to other systems that require human intervention,such as space robotic arms,robonauts,unmanned deep-sea vehicles,and rescue robots,particularly when there is considerable time delay.

In situ Lu–Hf phosphate geochronology:Progress towards a new tool for space exploration

Geochronology is fundamental to understanding planetary evolution.However,as space exploration continues to expand,traditional dating methods,involving complex laboratory processes,are generally not realistic for unmanned space applications.Campaign-style planetary exploration missions require dating methods that can(1)rapidly resolve age information on small samples,(2)be applied to minerals common in mafic rocks,and(3)be based on technologies that could be installed on future rover systems.We demonstrate the application of rapid in situ microanalytical Lu–Hf phosphate geochronology using samples of pallasite meteorites,which are representative examples of the deep interiors of differentiated planetoids that are generally difficult to date.Individual pallasites were dated by laser ablation tandem mass-spectrometry(LA-ICP-MS/MS),demonstrating a rapid novel method for exploring planetary evolution.Derived formation ages for individual pallasites agree with traditional methods and have<2%uncertainty,opening an avenue of opportunity for remote micro-analytical space exploration.

SoSpider:A bio-inspired multimodal untethered soft hexapod robot for planetary lava tube exploration

Soft robots have tremendous potential for applications in various fields,owing to their safety and flexibility embedded at the material level.Soft robots,especially bio-inspired soft legged robots,have become one of the most active fields of current research in robotics thanks to their superior mobility and ability to face complex terrains.However,it is arduous to establish a dynamic simulation model for soft robots,owing to their hyper-redundant degrees of freedom,hyper-elasticity,and nonlinearity of their soft structures.In this study,we designed,simulated,and fabricated a hexapod robot that achieves walking,crawling,pronking,and rolling with wheeled legs plus a soft body capable of shape change.A robot prototype was fabricated using 3D printing technology and soft silicone pneumatic networks.Actuators,battery power,and control boards were integrated into the body of the robot for untethered locomotion.We have explored the capabilities of the robot in different conditions,especially in scenarios that simulate lunar and Martian environments,demonstrating the motion performance of the robot.The results have shown promising potentials of the developed robot for future applications in planetary lava tube exploration.Our experimental and simulation results also show good agreements that indicate the potential predictive roles of simulation tools for soft robot design,planning,and control.

Attitude Control Experiments of Cubic Rover on Low-Gravity Testbed

In-situ exploration of asteroid surfaces is of great scientific significance.Internally actuated rovers have been released to asteroid surfaces but without enough controllability.To investigate the attitude control characteristics of the cubic rover for asteroid surface exploration,a series of experiments are carried out using the self-designed rover and the low-gravity testbed.The experiments focus on two major themes:The minimum flywheel speed for cubic rover to produce a walking motion in different conditions,and the relationship between the rover’s rotation angle and the flywheel speed in twisting motion.The rover’s dynamical descriptions of the walking and twisting motions are first derived.The features and design of the low-gravity testbed are then summarized,including its dynamics,setup,and validation.A detailed comparison between the dynamic model and the experimental results is presented,which provides a basic reference of the cubic rover’s attitude control in low-gravity environments.

In-Flight Total Dose Estimation Using RADEM Instrument on JUICE

Missions flying to giant planets frequently provide telemetry data after substantial time lag. Determination of crucial environmental characteristic sometimes detrimental for the mission health may be further delayed by duration of subsequent data analysis. We propose a fast method used in-flight to assess the electron total ionizing dose and dose rate onboard of the JUICE ESA mission to JUPITER. The procedure provides estimated values of dose rate behind various thickness of shielding using counting rates from the electron telescope EHD of the RADEM radiation hard electron monitor instrument onboard JUICE.

A dimension reduced INS/VNS integrated navigation method for planetary rovers

Inertial navigation system/visual navigation system(INS/VNS) integrated navigation is a commonly used autonomous navigation method for planetary rovers. Since visual measurements are related to the previous and current state vectors(position and attitude) of planetary rovers, the performance of the Kalman filter(KF) will be challenged by the time-correlation problem. A state augmentation method, which augments the previous state value to the state vector, is commonly used when dealing with this problem. However, the augmenting of state dimensions will result in an increase in computation load. In this paper, a state dimension reduced INS/VNS integrated navigation method based on coordinates of feature points is presented that utilizes the information obtained through INS/VNS integrated navigation at a previous moment to overcome the time relevance problem and reduce the dimensions of the state vector. Equations of extended Kalman filter(EKF) are used to demonstrate the equivalence of calculated results between the proposed method and traditional state augmented methods. Results of simulation and experimentation indicate that this method has less computational load but similar accuracy when compared with traditional methods.

Modeling and analysis of Hayabusa2 touchdown

The Hayabusa2 asteroid explorer mission focuses principally on the touchdown and sampling on near-Earth asteroid 162173 Ryugu.Hayabusa2 successfully landed on its surface and ejected a projectile for sample collection on February 22,2019.Hayabusa2 later landed near a crater formed by an impactor and executed the sampling sequence again on July 11,2019.For a successful mission,a thorough understanding and evaluation of spacecraft dynamics during touchdown were crucial.The most challenging aspect of this study was the modeling of such spacecraft phenomena as the dynamics of landing on a surface with unknown properties.In particular,a Monte Carlo analysis was used to determine the parameters of the operational design for the final descent and touchdown sequence.This paper discusses the dynamical modeling of the simulation during the touchdown of Hayabusa2.