©, 2015, Chinese Academy of Sciences. All right reserved.Marvi et al (Science, 2014, vol.346, p.224) concluded a sidewinder rattlesnake increases the body contact length with the sand when granular incline angle increases. They also claimed the same principle should work on robotic snake too. We have evidence to prove that this conclusion is only partial in describing the snake body-sand interaction. There should be three phases that fully represent the snake locomotion behaviors during ascent of sandy slopes, namely lifting, descending, and ceasing. The snake body-sand interaction during the descending and ceasing phases helps with the climbing while such interaction during the lifting phase in fact contributes resistance.

A robot system with double manipulators used for minimally invasive surgery(MIS) is developed,which can perform operation precisely in the abdomen through cooperation with the instruments.By analyzing the operation environment and characteristics of the MIS,the basic requirements for the mechanical design of manipulator to perform MIS operations are presented.Based on those analysis and requirements,the paper mainly focuses on the mechanical design and optimization of the manipulator.According to the actual requirements of MIS,the manipulator can execute preoperative incision positioning,intraoperative instruments operating and instruments dismounting and replacing.Moreover,the mechanical design of the manipulator can also guarantee the instruments to stay unchangeably at the incision of the patient,which can avoid the non-operative damage to the incision caused by the instrument’s operating movements.Furthermore,by using the singular value of the robotics Jacobian matrix,a comprehensive dexterity evaluation index function based on conditional number and operability of the manipulator is proposed,and the dimensional parameters of the manipulator are optimized by adopting the sequential quadratic programming(SQP) algorithm.The optimization results indicate that the manipulator features isotropy and operability,and meets the MIS requirements for commendable mechanical dexterity.

According to locally autonomous and remote control modes for a power transmission line inspection robot, an FSM(finite state machine) based motion planning method for obstacle navigation is presented.The obstacle navigation processes of the inspection robot are divided into several key discrete states,and FSM models for motion planning are established.A fuzzy-based production system is offered for deducing obstacle navigation modes and producing the motion sequences.Simulation and field experiments prove that the motion planning method for obstacle navigation is correct and valid,and can be applied to motion control of the power transmission line inspection robot.

A two-stage state recognition method is proposed for asynchronous SSVEP(steady-state visual evoked potential) based brain-computer interface(SBCI) system.The two-stage method is composed of the idle state(IS) detection and control state(CS) discrimination modules.Based on blind source separation and continuous wavelet transform techniques,the proposed method integrates functions of multi-electrode spatial filtering and feature extraction.In IS detection module,a method using the ensemble IS feature is proposed.In CS discrimination module,the ensemble CS feature is designed as feature vector for control intent classification.Further,performance comparisons are investigated among our IS detection module and other existing ones.Also the experimental results validate the satisfactory performance of our CS discrimination module.

A single actuated bio-mimetic robotic fish is designed based on forced vibration responses of a non-prismatic cantilever which mimick the fish body deformation.The deforming dynamical equations of the fish body during its selfpropelled swimming process are developed.Then,the dynamical characteristics of the burst-and-coast swimming mode of the fish are studied by numerical simulations.The simulation results show that higher swimming efficiency can be achieved by changing the ratio between burst time and coast time,which add a new high-efficiency control mode of robotic fish.

Firstly,strategic demands of ocean exploration technologies and equipments in four aspects are analyzed,including ocean exploitation and economic growth,maritime rights and interests maintenance and maritime security,construction of ocean ecological civilization and marine scientific progress.Secondly,the current situation of ocean exploration technologies and equipments is reviewed,and development tendency is pointed out.Lastly,according to status of ocean exploration technologies and equipments in China,existing problems are presented,and advices and measures are proposed.

In order to achieve qualitative and quantitative evaluation of autonomous navigation trajectory,a trajectory analysis method based on uncertainty cloud model is proposed.In this method,robot’s trajectory features are extracted from autonomous driving and avoiding actions,and corresponding feature cloud models for position warp,direction warp and obstacle-avoidance safety distance trajectories are generated.In cloud model,expectation is the basic metric of trajectories,and the fuzziness and randomness of features are expressed by entropy and hyper-entropy.By taking advantages of uncertainty metric of cloud models,the transient state and stability in autonomous navigation can be calculated.Experiment results show that this method can effectively be used in trajectory evaluation of autonomous navigation,and it can compensate shortcomings of reinforcement learning methods in stability evaluation.

A pre-selected minimum distance index is presented considering the real-time performance of dynamic obstacle avoidance for redundant robots.The OBB(oriented bounding box) is applied to modeling robot,and safe links are removed by intersection test before calculating real-time distance.The real-time minimum distance is calculated by local mapping based distance calculation method according to the coordinates of objective points.Based on that,avoidance factor and escaping velocity related to minimum distance are built and then mapping matrix in zero space of redundant robots is utilized to accomplish obstacle avoidance path planning.Finally,the validity and efficiency of pre-selected minimum distance index for dynamic obstacle avoidance are manifested by simulation.Compared with traditional path planning methods,the overall planning time is reduced by 15.5%.

The paper systematically and comprehensively introduces the operation environments,functional requirements, structure designs,dynamic and control researches of the deep ocean mining robots at home and abroad according to different mineral resources,including the polymetallic nodules,cobalt-rich crusts and polymetallic sulfides.The achievements and shortages of the deep ocean mining robots researches in China are summarized,and the existing gaps compared with the advanced countries are pointed out.Finally,the key technologies to be urgently improved and the future development trends of the deep ocean mining robots are proposed.