To establish a universal and easily controlled gait for practical use of snakelike robot movement, an inchworm locomotion gait model based on a serpenoid curve is presented. By analyzing the relations of two adjacent ...To establish a universal and easily controlled gait for practical use of snakelike robot movement, an inchworm locomotion gait model based on a serpenoid curve is presented. By analyzing the relations of two adjacent waves in the process of locomotion and doing an approximation of the serpenoid curve, the motion function of relative angles between two adjacent links and the absolute angles between each link and the baseline on the traveling curve are built. Two efficiency criterions of the gait are given as the energy loss function f and the unit displacement in one cycle dunit.Three parameters of the criterions affecting the efficiency of the gait （ the number of links that form the traveling wave n, the included angle between two adjacent links α, and the phase difference of adjacent included angles β） are discussed by simulations and experiments. The results show that f is insensitive to n; raising n increases dunit significantly; the maximum wave amplitude of α is a decreasing function of n; and increasing α reduces the displacement influence off when n is determined. The gait model is suitable for different inchworm locomotions of a snakelike robot whose traveling waves are formed by different numbers of identical links. A wave formed by more links or a greater relative angle between two adjacent links both lead to greater velocity of the movement.展开更多
A unilateral self-locking mechanism(USM) was proposed to increase the tractive ability of the inchworm in-pipe robots for pipeline inspection.The USM was basically composed of a cam,a torsional spring and an axis.The ...A unilateral self-locking mechanism(USM) was proposed to increase the tractive ability of the inchworm in-pipe robots for pipeline inspection.The USM was basically composed of a cam,a torsional spring and an axis.The self-locking and virtual work principles were applied to studying the basic self-locking condition of the USM.In order to make the cooperation between the crutch and telescopic mechanism more harmonical,the unlocking time of the USM was calculated.A set of parameters were selected to build a virtual model and fabricate a prototype.Both the simulation and performance experiments were carried out in a pipe with a nominal inside diameter of 160 mm.The results show that USM enables the robot to move quickly in one way,and in the other way it helps the robot get self-locking with the pipe wall.The traction of the inchworm robot can rise to 1.2 kN,beyond the limitation of friction of 0.497 kN.展开更多
At the present time, ultrasonic motors have been developed for a variety of purposes such as linear motion drives and rotational drives. The elaboration of an ultrasonic motor is time-consuming, because it is develope...At the present time, ultrasonic motors have been developed for a variety of purposes such as linear motion drives and rotational drives. The elaboration of an ultrasonic motor is time-consuming, because it is developed adapting on its application. In this study, a new ultrasonic motor structure that combines a piezoelectric element and a metallic plate is elaborated. The driving principle of this motor is that the metal plate is bent to an inchworm shape and rotates the rotor when the piezoelectric element is stretched. The objective of this study is to verify the functioning of the new motor experimentally.展开更多
An inchworm-like capsule robot(ILCR) is a promising device for a minimally invasive diagnosis and treatment of colon diseases. It consists of two expanders and one extensor, the former provides a traction force by exp...An inchworm-like capsule robot(ILCR) is a promising device for a minimally invasive diagnosis and treatment of colon diseases. It consists of two expanders and one extensor, the former provides a traction force by expanding the colon and the latter can elongate and retract to enable active locomotion. However, the locomotion efficiency of the ILCR can be seriously lowered by the complex colon environment featuring slippery, viscoelastic, and suspend properties, which has been a main obstacle to its clinical application. This paper aims at improving the locomotion efficiency of the ILCR by optimizing its extensor design. To do this, the locomotion resistance of the ILCR in the colon is analyzed, and complying with a requirement that the traction force must be larger than the locomotion resistance to avoid slipping, a restriction on the extensor design is obtained. Then under the restriction and with reference to the Hyperelastic model which correlates stress and strain of colon tissue, a model for analyzing the influence of the design parameters of the extensor on the locomotion efficiency of the ILCR is built. With this model, the extensor has been optimized and the optimized results have been used to guide the development of a novel extensor, which employs two pairs of lead-screws and nuts and is actuated by one motor. Ex-vivo experiment has shown that the novel extensor can improve the locomotion efficiency of an ILCR prototype by 57%, without changing its total length.展开更多
A small resonant inchworm piezoelectric robot with six driving feet which are set evenly along the circumference is proposed and tested.A bonded-type structure is adopted to realize a small size.The radial bending vib...A small resonant inchworm piezoelectric robot with six driving feet which are set evenly along the circumference is proposed and tested.A bonded-type structure is adopted to realize a small size.The radial bending vibration mode and longitudinal vibration mode are excited at the same frequency.The superposition of these two vibration modes makes the driving feet produce elliptical motions.And the driving force can be generated by friction coupling between the driving foot and the operating plane.The structure of the robot is designed by finite element simulation.The geometric parameters are adjusted to make the resonant frequencies of the vibration modes as close as possible.The elliptical trajectories generated at the driving feet are discussed in detail.The vibration and motion characteristics of the prototype are tested,and the resonant frequencies of the radial bending mode and the longitudinal vibration mode are degenerated successfully.The optimal working frequency of the prototype is 21.5 kHz.The maximum speed of the prototype is 200 mm/s,and the displacement resolution is 0.71μm.The measured results show that the resonant inchworm piezoelectric robot can be used for fast and high-precision transportation in narrow space.展开更多
文摘To establish a universal and easily controlled gait for practical use of snakelike robot movement, an inchworm locomotion gait model based on a serpenoid curve is presented. By analyzing the relations of two adjacent waves in the process of locomotion and doing an approximation of the serpenoid curve, the motion function of relative angles between two adjacent links and the absolute angles between each link and the baseline on the traveling curve are built. Two efficiency criterions of the gait are given as the energy loss function f and the unit displacement in one cycle dunit.Three parameters of the criterions affecting the efficiency of the gait （ the number of links that form the traveling wave n, the included angle between two adjacent links α, and the phase difference of adjacent included angles β） are discussed by simulations and experiments. The results show that f is insensitive to n; raising n increases dunit significantly; the maximum wave amplitude of α is a decreasing function of n; and increasing α reduces the displacement influence off when n is determined. The gait model is suitable for different inchworm locomotions of a snakelike robot whose traveling waves are formed by different numbers of identical links. A wave formed by more links or a greater relative angle between two adjacent links both lead to greater velocity of the movement.
基金Project(2007AA04Z256) supported by the National High-Tech Research and Development Program of China
文摘A unilateral self-locking mechanism(USM) was proposed to increase the tractive ability of the inchworm in-pipe robots for pipeline inspection.The USM was basically composed of a cam,a torsional spring and an axis.The self-locking and virtual work principles were applied to studying the basic self-locking condition of the USM.In order to make the cooperation between the crutch and telescopic mechanism more harmonical,the unlocking time of the USM was calculated.A set of parameters were selected to build a virtual model and fabricate a prototype.Both the simulation and performance experiments were carried out in a pipe with a nominal inside diameter of 160 mm.The results show that USM enables the robot to move quickly in one way,and in the other way it helps the robot get self-locking with the pipe wall.The traction of the inchworm robot can rise to 1.2 kN,beyond the limitation of friction of 0.497 kN.
文摘At the present time, ultrasonic motors have been developed for a variety of purposes such as linear motion drives and rotational drives. The elaboration of an ultrasonic motor is time-consuming, because it is developed adapting on its application. In this study, a new ultrasonic motor structure that combines a piezoelectric element and a metallic plate is elaborated. The driving principle of this motor is that the metal plate is bent to an inchworm shape and rotates the rotor when the piezoelectric element is stretched. The objective of this study is to verify the functioning of the new motor experimentally.
基金supported by the National Natural Science Foundation of China(Grant Nos.61803347,61673271&81601631)the Shanxi Province Science Foundation for Youths(Grant No.201801D221201)+3 种基金the Youth Academic Leader Support Project of North University of China(Grant No.QX201808)the Opening Foundation of Shanxi Key Laboratory of Advanced Manufacturing Technology(Grant No.XJZZ201803)the Science and Technology Commission of Shanghai Municipality(Grant No.15441903100)the Science and Technology on Electronic Test and Measurement Laboratory,North University of China(Grant No.WD614200104011804)
文摘An inchworm-like capsule robot(ILCR) is a promising device for a minimally invasive diagnosis and treatment of colon diseases. It consists of two expanders and one extensor, the former provides a traction force by expanding the colon and the latter can elongate and retract to enable active locomotion. However, the locomotion efficiency of the ILCR can be seriously lowered by the complex colon environment featuring slippery, viscoelastic, and suspend properties, which has been a main obstacle to its clinical application. This paper aims at improving the locomotion efficiency of the ILCR by optimizing its extensor design. To do this, the locomotion resistance of the ILCR in the colon is analyzed, and complying with a requirement that the traction force must be larger than the locomotion resistance to avoid slipping, a restriction on the extensor design is obtained. Then under the restriction and with reference to the Hyperelastic model which correlates stress and strain of colon tissue, a model for analyzing the influence of the design parameters of the extensor on the locomotion efficiency of the ILCR is built. With this model, the extensor has been optimized and the optimized results have been used to guide the development of a novel extensor, which employs two pairs of lead-screws and nuts and is actuated by one motor. Ex-vivo experiment has shown that the novel extensor can improve the locomotion efficiency of an ILCR prototype by 57%, without changing its total length.
基金supported by the National Natural Science Foundation of China(Grant Nos.5210051275 and U1913215)the China Postdoctoral Science Foundation(Grant No.2021M690830)the Postdoctoral Science Foundation of Heilongjiang Province(Grant No.LBH-Z21018)。
文摘A small resonant inchworm piezoelectric robot with six driving feet which are set evenly along the circumference is proposed and tested.A bonded-type structure is adopted to realize a small size.The radial bending vibration mode and longitudinal vibration mode are excited at the same frequency.The superposition of these two vibration modes makes the driving feet produce elliptical motions.And the driving force can be generated by friction coupling between the driving foot and the operating plane.The structure of the robot is designed by finite element simulation.The geometric parameters are adjusted to make the resonant frequencies of the vibration modes as close as possible.The elliptical trajectories generated at the driving feet are discussed in detail.The vibration and motion characteristics of the prototype are tested,and the resonant frequencies of the radial bending mode and the longitudinal vibration mode are degenerated successfully.The optimal working frequency of the prototype is 21.5 kHz.The maximum speed of the prototype is 200 mm/s,and the displacement resolution is 0.71μm.The measured results show that the resonant inchworm piezoelectric robot can be used for fast and high-precision transportation in narrow space.
