Shilian Mao

A Novel Soft Biomimetic Microrobot with Two Motion Attitudes

A variety of microrobots have commonly been used in the fields of biomedical engineering and underwater operations during the last few years. Thanks to their compact structure, low driving power, and simple control systems, microrobots can complete a variety of underwater tasks, even in limited spaces. To accomplish our objectives, we previously designed several bio-inspired underwater microrobots with compact structure, flexibility, and multi-functionality, using ionic polymer metal composite (IPMC) actuators. To implement high-position precision for IPMC legs, in the present research, we proposed an electromechanical model of an IPMC actuator and analysed the deformation and actuating force of an equivalent IPMC cantilever beam, which could be used to design biomimetic legs, fingers, or fins for an underwater microrobot. We then evaluated the tip displacement of an IPMC actuator experimentally. The experimental deflections fit the theoretical values very well when the driving frequency was larger than 1 Hz. To realise the necessary multi-functionality for adapting to complex underwater environments, we introduced a walking biomimetic microrobot with two kinds of motion attitudes: a lying state and a standing state. The microrobot uses eleven IPMC actuators to move and two shape memory alloy (SMA) actuators to change its motion attitude. In the lying state, the microrobot implements stick-insect-inspired walking/rotating motion, fish-like swimming motion, horizontal grasping motion, and floating motion. In the standing state, it implements inchworm-inspired crawling motion in two horizontal directions and grasping motion in the vertical direction. We constructed a prototype of this biomimetic microrobot and evaluated its walking, rotating, and floating speeds experimentally. The experimental results indicated that the robot could attain a maximum walking speed of 3.6 mm/s, a maximum rotational speed of 9°/s, and a maximum floating speed of 7.14 mm/s. Obstacle-avoidance and swimming experiments were also carried out to demonstrate its multi-functionality.

Development of an Amphibious Turtle-Inspired Spherical Mother Robot

Robots play an important role in underwater monitoring and recovery operations, such as pollution detection, submarine sampling and data collection, video mapping, and object recovery in dangerous places. However, regular-sized robots may not be suitable for applications in some restricted underwater environments. Accordingly, in previous research we designed several novel types of bio-inspired microrobots using Ionic Polymer Metal Composite (IPMC) and Shape Memory Alloy (SMA) actuators. These microrobots possess some attributes of compact structure, multi-functionality, flexibility, and precise positioning. However, they lack the attributes of long endurance, stable high speed, and large load capacity necessary for real-world applications. To overcome these disadvantages, we proposed a mother-son robot system, composed of several microrobots as sons and a newly designed amphibious spherical robot as the mother. Inspired by amphibious turtles, the mother robot was designed with a spherical body and four legs with two Degrees of Freedom (DOF). It is actuated by four vectored water-jet propellers and ten servomotors, and it is capable of walking on land and cruising underwater. We analysed the mother robot’s walking and underwater cruising mechanisms, constructed a prototype, and carried out a series of experiments to evaluate its amphibious motions. Good motion performance was observed in the experiments.

Development of an amphibious mother spherical robot used as the carrier for underwater microrobots

Nowadays, smart materials actuated microrobots are widely used when dealing with complicated missions in limited spaces. But problems still exist in this kind of solutions, such as low locomotion speed and short operating time. To solve these problems, we propose a mother-son multi-robots cooperation system, named GSL system, which included several microrobots as son robots, and a novel designed amphibious spherical robot as the mother robot. The mother robot, called GSLMom, was designed to be able to carry microrobots and provide power supply for them. This paper will talk about the structure and mechanism of the GSLMom robot. The GSLMom robot was designed as an amphibious spherical one. The robot was equipped with a 4 unit locomotion system, and each unit consists of a water-jet propeller and two servo motors. Each servo motor could rotate 90° in horizontal and 120° in vertical direction respectively. When moving in water, servo motors controlled the directions of water jet propellers and the 4 propellers work to actuate the robot. In the ground situation, propellers were used as legs, and servo motors actuated these legs to realize walking mechanism. After discussed structures, experiments were conducted to evaluate performance of the actuators.

Design and kinematic analysis of an amphibious spherical robot

Nowadays, microrobots are being widely researched in order to deal with complicated missions in limited spaces. But important abilities such as locomotion velocity and enduring time are usually sacrificed in order to realize compact sizes. To solve these problems, we proposed a mother-son multi-robots cooperation system, named GSL system, which included several microrobots as son robots, and a novel designed amphibious spherical robot as the mother robot. The mother robot, which was called GSLMom robot, was designed to be able to carry microrobots and provide power supply for them. This paper will mainly focus on the structure and mechanism of the GSLMom robot. The GSLMom robot, which was designed as an amphibious spherical one, was shaped by a fixed hemisphere hull, and two openable quarter ball hulls. The robot was equipped with a 4 unit locomotion system, and each unit consists of a water jet propeller and two servo motors. Each servo motor could rotate 90° in horizontal or vertical direction respectively. When moving in water, servo motors controlled the directions of water jet propellers and the 4 propellers worked to actuate the robot. With this mechanism, the robot could realize moving forward, backward, rotating, floating and sinking motion in water. In the ground situation, propellers were used as legs, and servo motors actuated these legs to realize walking mechanism, so that the robot could realize moving forward, backward, and rotating motions on the ground. After discussed structures, actuating strategies were proposed for the robot. And kinematic models of the robot were also built.

Development of a Lobster-Inspired Underwater Microrobot

Biomimetic underwater microrobots are of great interest for underwater monitoring operations, such as pollution detection and video mapping in restricted underwater environments. Generally speaking, compact structure, multi-functionality, flexibility and precise positioning are considered incompatible characteristics for underwater microrobots. Nevertheless, we have designed several novel types of bio-inspired locomotion, using ionic polymer metal composite (IPMC) and shape memory alloy (SMA) actuators. We reviewed a number of previously developed underwater microrobot prototypes that were constructed to demonstrate the feasibility of these types of biomimetic locomotion. Based on these prototypes, we summarized the implemented techniques and available results for efficient and precise underwater locomotion. In order to combine compact structure, multi-functionality, flexibility and precise positioning, we constructed a prototype of a new lobster-like microrobot and carried out a series of experiments to evaluate its walking, rotating, floating and grasping motions. Diving/surfacing experiments were performed by electrolyzing the water around the surfaces of the actuators. Three proximity sensors were installed on the microrobot to detect an object or avoid an obstacle while walking.

A smart actuator-based underwater microrobot with two motion attitudes

Various microrobots were widely used in the fields of biomedical engineering and underwater operation during the last few years. By having a compact structure, low driving voltage and a simple control system, microrobots could complete a variety of underwater tasks, even in limited spaces. To realize the multifunctionality of the microrobot for adapting to complex underwater environments, we proposed a walking biomimetic microrobot with two kinds of motion attitudes, lying state and standing state. The microrobot used eleven ICPF (ionic conducting polymer film) actuators to move and two SMA (shape memory alloy) actuators to change motion attitude. In the lying state, the microrobot could implement stick insect-inspired walking/rotating motion, fish-like swimming motion, horizontal grasping motion, and floating motion. In the standing state, it could implement inchworm-inspired crawling motion along two directions and vertical grasping motion. Then we developed a prototype of multi-functional biomimetic microrobot and evaluated its walking, rotating and floating speeds experimentally. Experimental results indicated that the robot could obtain a maximal walking speed of 3.6mm/s, a maximal rotating speed of 9deg/s and a maximal floating speed of 7.14mm/s.

Development of a spherical amphibious mother robot

A variety kinds of underwater robots have been developed for the uses of underwater investigation and underwater operation. For those tasks in complicated or tiny underwater environments, some kinds of underwater microrobots have been developed. Thanks to the developments of smart actuators, microrobots realized relatively high performance within a compact structure. But problems in velocity and sustainable time limited their application. To solve this problem, we proposed a mother-son robot system, which include several microrobots as son robots, and an amphibious spherical robot as the mother robot. In this paper, a mother robot was proposed. It was designed to be able to walk on land, as well as move in water using a vectored water-jet mechanism. As the mother robot in the under-developing system, it also contained the space for transporting microrobots, and two openable hulls to protect the microrobots from the water currents and obstacles in water. A pressure sensor was used to determine whether robot was on land or in water, and measure the depth while in the underwater situation. To avoid obstacles, eight infrared distance sensors were used to detect obstacles in all the directions around the robot. In order to evaluate the robots underwater performance, some experiments were conducted.

Development and experiments of a novel multifunctional underwater microrobot

Compact structure, multifunction, and flexibility are normally considered as incompatible characteristics for legged microrobots. Most robots focused on complex structure of multi-joint legs to attain the multifunction and flexibility, while others had poor flexibility for miniaturization. In the field of underwater monitoring for applications such as pollution detection and video mapping in limited space, underwater microrobots are urgently demanded. To realize these purposes, we have developed several types of microrobots with both compact structure and flexible locomotion. However, they just realized walking, rotating, swimming, or floating motions. Without biomimetic fingers, they could not do some simple operations, such as grasping and carrying any objects to desired place. So, in this paper, we designed a novel type of biomimetic locomotion employing ionic polymer metal composite (IPMC) actuator as one-DOF leg. Then we proposed a new type of underwater microrobot using ten ionic polymer metal composite (IPMC) actuators as legs or fingers, which could realize walking, rotating, floating, and grasping motions. Also, we developed a prototype of this underwater microrobot and carried out some experiments to evaluate its walking and floating speeds. In addition, we used six IPMC actuators as fingers to grasp some small objects and float up. To realize the closed-loop control for the microrobot, we used three proximity sensors to detect and avoid the obstacle while walking.

Development of a novel underwater biomimetic microrobot with two motion attitudes

In the last few years, various microrobots were applied more and more in the fields of biomedical engineering and underwater operation. By having a compact structure, low driving voltage and a simple control system, microrobots could do a variety of underwater missions, especially in limited spaces. To realize the purpose of multifunction of the microrobot aiming at adapting to the complex underwater environment, we proposed a walking biomimetic microrobot which had two kinds of motion attitudes. The microrobot used eleven ICPF (ionic conducting polymer film) actuators for locomotion and missions and two SMA (shape memory alloy) actuators for attitude change. In lying structure, the microrobot could implement stick insect-inspired walking/rotating motions by using eight ICPF legs, fish-like swimming motion by using one ICPF tail fin, horizontal grasping motion by using two ICPF fingers, and floating motion by electrolyzing water. In standing structure, it could implement inchworm-inspired crawling motion along two directions and vertical grasping motion by using inside four legs. Then we developed a prototype of multi-functional biomimetic microrobot and evaluated the walking speed and floating speed experimentally for performance testing.