Development and control of flexible pneumatic wall-climbing robot

A new kind of flexible pneumatic wall-climbing robot,named WALKMAN-I,was proposed. WALKMAN-I is basically composed of a flexible pneumatic actuator (FPA),a flexible pneumatic spherical joint and six suction cups. It has many characteristics of low-cost,lightweight,simple structure and good flexibility. Its operating principle was introduced. Then three basic locomotion modes,which are linear motion,curvilinear motion and crossing the orthogonal planes,were presented. The safety conditions of WALKMAN-I were discussed and built. Finally,the control system was designed and experiments were carried out. Experimental results show that WALKMAN-I is able to climb on the vertical wall surface along a straight line or a curved path,and has the ability of crossing orthogonal planes and obstacles. The maximum rotation angle reaches 90°,the maximum velocity reaches 5 mm/s,and the rotation angle and the moving velocity of WALKMAN-I can be easily controlled.

Adsorption Performance of Sliding Wall-Climbing Robot

Sliding wall-climbing robot （SWCR） is applied worldwide for its continuous motion, however, considerable air leakage causes two problems： great power consumption and big noise, and they constraint the robot＇s comprehensive performance. So far, effective theoretical model is still lacked to solve the problems. The concept of SWCR＇s adsorption performance is presented, and the techniques of improving utilization rate of given adsorption force and utilization rate of power are studied respectively to improve SWCR＇s adsorption performance. The effect of locomotion mechanism selection and seal＇s pressure allocation upon utilization rate of given adsorption force is discussed, and the theoretical way for relevant parameters optimization are provided. The directions for improving utilization rate of power are pointed out based on the detail analysis results of suction system＇s thermodynamics and hydrodynamics. On this condition, a design method for SWCR-specific impeller is presented, which shows how the impeller＇s key parameters impact its aerodynamic performance with the aid of computational fluid dynamics （CFD） simulations. The robot prototype, BIT Climber, is developed, and its functions such as mobility, adaptability on wall surface, payload, obstacle ability and wall surface inspection are tested. Through the experiments for the adhesion performance of the robot adsorption system on the normal wall surface, at the impeller＇s rated rotating speed, the total adsorption force can reach 237.2 N, the average effective negative pressure is 3.02 kPa and the design error is 3.8% only, which indicates a high efficiency. Furthermore, it is found that the robot suction system＇s static pressure efficiency reaches 84% and utilization rate of adsorption force 81% by the experiment. This thermodynamics model and SWCR-specific impeller design method can effectively improve SWCR＇s adsorption performance and expand this robot applicability on the various walls. A sliding wall-climbing robot with high adhesion efficiency is developed, and this robot has the features of light body in weight, small size in structure and good capability in payload.

Research on Alternatively Moving Vacuum Absorbing Wall-climbing Robot

In conection with the complex working-surroundings of the wall-climbing Robot, this paper researched akind of alternatively moving mechanism with good obstacle-surmounting ability and high moving speed, making use ofthe thought of bionics. This paper designed a kind of self-adjusting multi-vacuum sucker. Furthermore, it employedthe theory of vacuum system to establish the work mathematics madel of control switch to are sucking disc and presented the design parameter of the control switch. In addition, this paper made use of the thought of bionics to design aobstacle-surmounting mechanism used in wall-climbing robot. Also it employed the theory Of robotics to analyze the kinematics and the dynamics movement of die robot.

High-performance wall-climbingrobot for inspection and maintenance

A wall-climbing robot that can continuously work on many types of wall surfaces has been developed. This robot based on low-vacuum adsorption principle consists of a locomotion mecha- nism, a sealing device, a fluid machine and a detecting system. The adsorption force is analyzed in details and its influencing factors are given. The robot prototype, which has the features of high ad- hesion efficiency, light body in weight, small size in structure and good capability in payload, is test- ed in outdoor and indoor environments. Through the experiments, the influences of the impeller slit and the seal clearance are discussed. In addition, the robot functions such as adsorption perform- ance, locomotion performance and wall adaptability are tested by experiments. The experiments have verified that the robot not only can climb on many types of wall surfaces, but also has outstand- ing locomotion ability and payload capacity.

Fault detection and identification based on combining logic and model in a wall-climbing robot

A combined logic- and model-based approach to fault detection and identification （FDI） in a suction foot control system of a wall-climbing robot is presented in this paper. For the control system, some fault models are derived by kinematics analysis. Moreover, the logic relations of the system states are known in advance. First, a fault tree is used to analyze the system by evaluating the basic events （elementary causes）, which can lead to a root event （a particular fault）. Then, a multiple-model adaptive estimation algorithm is used to detect and identify the model-known faults. Finally, based on the system states of the robot and the results of the estimation, the model-unknown faults are also identified using logical reasoning. Experiments show that the proposed approach based on the combination of logical reasoning and model estimating is efficient in the FDI of the robot.

On Transit Gait Programming of Six-legged Wall-climbing Robot

Transit gait programming is a key problem for a multi-legged robot to climb automatically from the ground up the wall, as well as between wall intersections. In this paper, a new idea is put forward by which the complex transit gait is decomposed into a sequence of two relatively simpler parts - single-leg motion and body pitching motion. An algorithm based on the above concept shows its feasibility and effectiveness in the graphic kinematics simulation.

Research on Gait Trajectory Planning of Wall-Climbing Robot Based on Improved PSO Algorithm

In order to reduce the labor intensity of high-altitude workers and realize the cleaning and maintenance of high-rise building exteriors,this paper proposes a design for a 4-DOF bipedal wall-climbing bionic robot inspired by the inchworm’s movement.The robot utilizes vacuum adsorption for vertical wall attachment and legged movement for locomotion.To enhance the robot’s movement efficiency and reduce wear on the adsorption device,a gait mimicking an inchworm’s movement is planned,and foot trajectory planning is performed using a quintic polynomial function.Under velocity constraints,foot trajectory optimization is achieved using an improved Particle Swarm Optimization(PSO)algorithm,determining the quintic polynomial function with the best fitness through simulation.Finally,through comparative experiments,the climbing time of the robot closely matches the simulation results,validating the trajectory planning method’s accuracy.

Highly adaptive triboelectric tactile sensor on the foot of autonomous wall-climbing robots for detecting the adhesion state and avoiding the hazard

Due to the excellent maneuverability and obstacle crossing of legged robots,it is possible for an autonomous legged wallclimbing robots to replace manual inspection of ship exterior panels.However,when the magnetic adsorption legged wallclimbing robot steps on the convex point or convex line of the wall,or even when the robot missteps,the robot is likely to detach from the ferromagnetic wall.Therefore,this paper proposes a tactile sensor for the legged magnetic adsorption wall-climbing robot to detect the magnetic adsorption state and improve the safety of the autonomous crawling of the robot.The tactile sensor mainly comprises a three-dimensional(3D)-printed shell,a tactile slider,and three isometric sensing units,with an optimized geometry.The experiment shows that the triboelectric tactile sensor can monitor the sliding depth of the tactile slider and control the light-emitting device(LED)signal light.In addition,in the demonstration experiment of detecting the adsorption state of the robot's foot,the triboelectric tactile sensor has strong adaptability to various ferromagnetic wall surfaces.Finally,this study establishes a robot gait control system to verify the feedback control ability of the triboelectric tactile sensor.The results show that the robot equipped with the triboelectric tactile sensor can recognize the dangerous area on the crawling wall and autonomously avoid the risk.Therefore,the proposed triboelectric tactile sensor has great potential in realizing the tactile sensing ability of robots and enhancing the safety and intelligent inspection of ultra-large vessels.

Design and Technical Development of Wall-Climbing Robots:A Review

Once working at heights is dangerous,it is a significant accident.These accidents brought substantial economic losses and caused a large number of casualties.Therefore,it is essential to use wall-climbing robots to replace manual work at heights.The design of the wall-climbing robot is inspired by the climbing action of insects or animals.An intelligent bionic robot device can carry special equipment to operate on the wall and perform some dangerous operations instead of firefighters or inspection personnel more efficiently.The scope of application is vast.This paper firstly summarizes the research progress of wall-climbing robots with three different moving methods:wheel-climbing,crawler-based,and leg-footed robots;summarizes the applications and breakthroughs of four adsorption technologies:negative pressure,magnetic force,bionic and electrostatic;discusses the application of motion control algorithms in wall-climbing robots.Secondly,the advantages and disadvantages of different migration modes and adsorption methods are pointed out.The distribution and advantages of the combined application of different migration modes and adsorption methods are analyzed.In addition,the future development trend of wall-climbing robots and the promoting effect of bionic technology development on wall-climbing robots are proposed.The content of this paper will provide helpful guidance for the research of wall-climbing robots.

A Four-legged Wall-climbing Robot with Spines and Miniature Setae Array Inspired by Longicorn and Gecko

In industrial applications,climbing robots are widely used for climbing and detection of rough or smooth pipe surfaces.Inspired by the special claws of longicorn is that can crawl on rough surfaces and the array of tiny bristles of geckos that can crawl on smooth surfaces,a new type of wall-climbing robot for rough or smooth surfaces is proposed in this paper.The bionic palms of the robot are suggested with special bionic hooks inspired by the longicorn and bionic adhesive materials inspired by the gecko with a good performance on adhering on the surfaces.The special bionic hooks are manufactured by the 3D printing method and the bionic adhesive materials are made by the polymer print lithography technology.These two different bionic adhere accessory are used on the robot’s palm to achieve climbing on the different surfaces.This foldable climbing robot can not only bend its own body to accommodate the cylindrical contact surfaces of different diameters,but also crawl on vertical rough and smooth surfaces using their bionic palms.

Design,Modeling and Experimentation of a Biomimetic Wall-climbing Robot for Multiple Surfaces

Wall-climbing robots can work on steep terrain and obtain environment information in three dimensions for human in real time,which can improve operation efficiency.However,traditional single-mode robots cannot ensure the stable attachment on complex wall surfaces.Inspired by the structure characteristics of flies and clingfishes,three bionic structures including the flexible spine wheel,the adhesive material and the adsorption system are proposed.Aiming at task requirements on multiple walls and based on the above three bionic structures,a wall-climbing robot with the composed mode of“grabbing+adhesion+adsorption”is presented v/a the law of mechanism configuration synthesis.Using static analysis,the safe attachment conditions for the robot on smooth and rough walls are that the adsorption force is 30 N or more.Based on Newton's Euler and Lagrange formulas,the dynamic equations of the robot on vertical walls are established to deduce that the maximum theoretical torque of the driving motor is 1.43 N·m at a uniform speed.Finally,the prototype of the wall-climbing robot is manufactured and tested on the vertical lime wall,coarse sandpaper wall and acrylic ceiling wall.Meanwhile,experiment results imply that the average maximum moving speed and the corresponding load are 7.19 cm·s-1 and 0.8 kg on the vertical lime wall,7.78 cm·s-1 and 0.6 kg on the coarse sandpaper wall,and 5.93 cm·s-1 and 0.2 kg on the acrylic ceiling wall respectively.These findings could provide practical reference for the robot’s application on walls.

A Three-row Opposed Gripping Mechanism with Bioinspired Spiny Toes for Wall-climbing Robots

This paper presents a study of a three-row opposed gripping mechanism made of bioinspired spiny toes.An insect Serica orientalis Motschulsky's tarsal system was first described and studied.A compliant single spiny toe model was established assuming that the contact asperities were spheres.Following the single toe contact model,a spiny toe array's contact model was then developed using asperity height's distribution fiinction.By studying the cngaging and disengaging process of the single toe,the mechanical behavior of the toe and toe array were addressed.The toes as well as the arrays were manufacturcd via rapid prototyping.A customized apparatus using dis-placement-control method has been carried out to measure the pull-in forces and pull-ofT positions of the single toe and toe array undcr various compression conditions.Based on the understanding,a three-row opposed gripping mechanism with radial configuration for wall-climbing robots was designed and fabricated according to the mechanical behaviors of the toe and array.Using an opposed spoke con figuration with 3 rows of 31 toes on each linkage array,the mechanism designed as a foot of climbing robots can vertically resist at least 1 kg of load on rough inverted surface,while the maximum normal load is as high as 31 N.The findings may provide a way in developing a high payload wall-climbing robot system for practical applications.

Effects of Pendular Waist on Gecko＇s Climbing： Dynamic Gait, Analytical Model and Bio-inspired Robot

Most quadruped reptiles, such as lizards, salamanders and crocodiles, swing their waists while climbing on horizontal or vertical surfaces. Accompanied by body movement, the centroid trajectory also becomes more of a zigzag path rather than a straight line. Inspired by gecko＇s gait and posture on a vertical surface, a gecko inspired model with one pendular waist and four active axil legs, which is called GPL model, is proposed. Relationship between the waist position, dynamic gait, and driving forces on supporting feet is analyzed. As for waist trajectory planning, a singular line between the supporting feet is found and its effects on driving forces are discussed. Based on the GPL model, it is found that a sinusoidal waist trajectory, rather than a straight line, makes the driving forces on the supporting legs smaller. Also, a waist close to the pygal can reduce the driving forces compared to the one near middle vertebration, which is in accord with gecko＇s body bending in the process of climbing. The principles of configuration design and gait planning are proposed based on theoretical analyses. Finally, a bio-inspired robot DracoBot is developed and both of the driving force measurements and climbing experiments reinforce theoretical analysis and the rationality of gecko＇s dynamic gait.

Experimental and numerical study of the adsorption performance of a vortex suction device using water-swirling flow

An electrically activated underwater suction device is designed to form an amazing amount of negative pressure by generating water swirling flow,which can make underwater wall-climbing robot stick to the wall surface allowing a ground clearance.For the purpose of a full understanding of the mechanism of the suction device,a series of experimental tests are carried out and a computational fluid dynamics(CFD)model is established.The results show that the suction force F is consistent between experimental tests and simulations.An insight into the flow phenomena of vortex suction device,including spatial velocity and pressure distribution,is given through numerical simulation analysis.Furthermore,the crucial parameters,i.e.,the rotation speedωand gap clearance h,are studied.Then the relationships of F-ωand F-h are clarified.It reveals that with the increasing of rotation speed,the suction force increases quadratically.And with the increasing of gap clearance,the suction force increases firstly and then decreases,so that a reasonable design interval of gap clearance can be got to obtain the required suction force for the engineering applications.