Zhongkui Wang

Ritsumeikan University · Department of Robotics

In 4D printing, structures with gradients in physical properties are 3D printed in order to dramatically increase deformation. For example, printing bilayer structures with passive and active layers has been proposed, however, these methods have the disadvantages that the material of each layer is mixed, and the modeling process is complicated. Her...

In the food industry, automation using robots is highly demanded due to the influence of labor shortage. In this paper, we developed a pneumatically driven soft robot hand with thin and flexible fingers having thickness of 5 mm. With the developed soft robot hand, it is possible to arrange and pack cakes of different sizes and shapes without damagi...

Automation has been adopted and realized in many industrial fields in recent years. However, it has been barely implemented in the field of dealing with living creatures. Therefore in this paper, we propose a robotic system for grasping and transporting jellyfish to automate operations involving living creatures. We created a wire-driven robotic gr...

This manuscript focuses on modeling of two-dimensional food shapes. Foods have much variation in their shapes. This paper presents a method to describe two-dimensional food shapes with variations based on approximated shapes and functional expansions.

Soft grippers, including the conventional parallel shell gripper, are fabricated using traditional rubber casting process. In this research, we propose a demolding-free casting approach that does not require demolding silicon rubber from the mold. The rigid shell component serves as not only the mold for casting but also a part of the shell gripper...

Finite deformation is the principal actuation basis of elastomer-based pneumatic soft actuators. Desired deformation behavior is the key design requirement for such actuators. The objective of current study is to optimize the design of a flat shell gripper and to investigate its interaction with a cylindrical object. Herein, we propose an analytica...

Soft tactile sensors have been extensively studied due to their promising potential in estimating applied forces while exhibiting mechanical compliance. Such sensors have been fabricated from a variety of composite materials and various techniques to advance their applications. Currently, the development of soft tactile sensor based on carbon nanot...

Despite developments in robotics and automation technologies, several challenges need to be addressed to fulfill the high demand for automating various manufacturing processes in the food industry. In our opinion, these challenges can be classified as: the development of robotic end-effectors to cope with large variations of food products with high...

This paper presents a robotic system for bulk picking of food materials. The system consists of a robotic manipulator, a 3D camera, and a parallel shell gripper. A 3D template matching was used to recognize the individual food material from a bulk. The parallel shell gripper constructed by rigid shell and soft chamber is pneumatically driven. The t...

This study proposes a food classification database for robotic handling. The proposed food classification database classifies a wide variety of food products according to their conditions and characteristics, and associates them with various soft robotic hands or grippers that are commercially available and under research and development. By buildi...

Automation in the food industry is not as developed as in the automotive industry because of difficulties in handling food products with large variations in shape, size, and mechanical properties. In this paper, a pneumatic-driven soft needle gripper is proposed for handling food materials. It was constructed using a soft membrane and multiple rigi...

Food products are usually difficult to handle for robots because of their large variations in shape, size, softness, and surface conditions. It is ideal to use one robotic gripper to handle as many food products as possible. In this study, a scooping-binding robotic gripper is proposed to achieve this goal. The gripper was constructed using a pneum...

Population aging in Japan is exacerbating the labor shortage problem in food industry, agriculture, and other labor-intensive industries. Recently, automation and IoT technologies become highly demanded in such industries for improving productivity and labor-saving. This article reviews the challenges of introducing automation in food industry and...

Robotics and automation in the food industry is not as widely applied as in other industries, such as automotive and electrical industries, due to the large variations in the shape and properties of food materials and the frequent alterations of food products. Robotic end effectors that can adapt to these variations and handle multiple types of foo...

A soft tactile fingertip was developed to provide the contact feedback on characteristics of an object for performing automatic assembly of electronic parts, such as a thin circuit board. However, designing a tactile fingertip with simple design and minimal number of sensors that can estimate orientation and the contact state of an object is a chal...

This paper proposes a sensor using conductive fabric that can detect proximity and contact by measuring the capacitance between the sensor and the surrounding environment. Due to the flexibility of the sensor used, it can be easily integrated with industrial robot arms to monitor proximity and contact between the robot and the surrounding environme...

To automate the process of flatfoot finite element (FE) modeling, a software plug-in was developed and introduced in this paper. The plug-in was written in Python and based on the Abaqus Scripting Interface. It consists of three modules: script data, GUI (graphic user interface), and script command. The plug-in is integrated into Abaqus/CAE and can...

Clinically in medializing calcaneal osteotomy (MCO), foot and ankle surgeons are facing difficulties in choosing appropriate surgical parameters due to the individual differences in deformities among flatfoot patients. Traditional cadaveric studies have provided important information regarding the biomechanical effects of tendons, ligaments, and pl...

Automating the lunch box packaging is a challenging task due to the high deformability and large individual differences in shape and physical property of food materials. Soft robotic grippers showed potentials to perform such tasks. In this paper, we presented four pneumatic soft actuators made of different materials and different fabrication metho...

This paper describes an active tactile sensing system that selects sensing modalities based on specific sensing tasks, by changing its morphology, called Wrin'Tac. This work was inspired by the human finger wet-induced \textit{wrinkle}, which is usually observed when one soaks in warm water for a period, and has been indicated as an efficient trans...

This paper presents a novel approach for active tactile sensation that utilizes soft morphological deformation. This work is inspired by human finger's wrinkles, which appear after a long time soaking in water, and has been indicated as an efficient mean for enhancement of gripping in wet environment. We created a tactile sensing system that is an...

The grasping dynamics between a soft gripper and a deformable object has not been investigated so far. To this end, a 3D printed soft robot gripper with modular design was proposed in this paper. The gripper consists of a rigid base and three modular soft fingers. A snap-lock mechanism was designed on each finger for easy attach-detach to the base....

This paper describes the modeling of a soft three-axis force sensor. The sensor has a cylindrical cantilever beam made of silicone rubber that compresses and bends when normal and tangential forces are applied. The displacement of the beam's end is calculated by measuring the change of the magnetic field emitted by a permanent magnet embedded in th...

A finite element (FE) model of flatfoot deformity was proposed in this paper for use in surgical simulations to improve individualized treatments. The external geometries of the flatfoot skeleton and encapsulated soft tissue were obtained by 3D reconstruction of CT images. A total of 63 major ligaments and the plantar fascia were manually created w...

Materials and textures identification is a desired ability for robots. Developing such systems require tactile sensors that have enough sensitivity and spatial resolution, and the computational intelligence to meaningfully interpret sensor data. This paper introduces a texture classification algorithm utilizing support vector machine (SVM) classifi...

This paper proposes a new disposable soft 3D force sensor that can be used to calculate either force or displacement and vibrations. It uses three Hall Effect sensors orthogonally placed around a cylindrical beam made of silicon rubber. A niobium permanent magnet is inside the silicon. When a force is applied to the end of the cylinder, it is compr...

Slippage on the fingertips is an important phenomenon that occurs constantly in our daily life. However, the mechanism behind the slippage, especially incipient slippage, which appears prior to overall slippage, has not been fully understood. In this paper, a 2D finite element (FE) model of the human fingertip was presented to study how the human f...

In this paper, we introduce the application of Japanese origami art to the floating system of unmanned helicopter model for the case of emergency landing. The “origami floating system” is integrated compactly in the helicopter and expands by an electronic controlled system when the helicopter lands on water. We tested our proposed floating system u...

We present the development of an anthropomorphic fingertip system that can be used in tactile sensing. These fingertips can detect force and vibrational modalities through force sensors and accelerometers. Among the advantages of this tactile system is its low cost and reliable construction. This fingertip was evaluated in grasping, manipulating an...

This paper focuses on tactile sensors capable of detecting incipient slip. First, a review on the state of the art in incipient slip detection technologies is conducted. Next, we explain tactile perception of the human hands, emphasising on the incipient slip sensing. The mechanism of incipient slip is explained via displacement and acceleration re...

Flatfoot is a foot condition caused by the collapse of the medial arch of the foot, and it can result in problems such as severe pain, swelling, abnormal gait, and difficulty walking. Despite being a very common foot deformity, flatfoot is one of the least understood orthopaedic problems, and the opinions regarding its optimal treatment vary widely...

We have proposed a Beam Bundle Model for modeling of a human fingertip during pushing and sliding action with friction, especially stick-to-slip transition, to overcome mentioned issues. In order to construct its three-dimensional non-homogeneous structure, we took sequence of magnetic resonant images, which bring consecutive cross-sectional layers...

Humans recognize textures using the tactile data obtained from the human somatosensory system. Recognition of textures allows humans discriminate objects and materials. Moreover, by understanding the object's or material's texture, the human intuitively estimates roughness and the friction properties of the object or the material. This ability is n...

Vitreous humor exhibits complex biomechanical properties and determination of these properties is essential for designing ophthalmic biomedical microdevices. In this paper, the viscoelastic properties of porcine vitreous humor were studied based on ex vivo creep experiments, in which a microrobot was magnetically actuated inside the vitreous. A thr...

A 3-D nonhomogeneous finite-element (FE) dynamic model of a primate fingertip is developed in this paper based on magnetic resonance (MR) imaging measurements for better understanding the mechanism of human finger sensation. The geometries of a human fingertip are measured using an MR system, and a series of 2-D images is obtained. Utilizing a boun...

In modern clinical practices, accurate orientation for needle-like tools inserting into soft tissues is cumbersome, mainly due to the tissue's non-linear deformation and the complicated combination of forces between the tissue and the tool. In this paper, the interaction between tissue deformation and friction forces has been discussed. We consider...

The purpose of this study is to accurately simulate the rheological behaviors of food objects undergoing a loading-unloading operation using finite element (FE) model. Due to the presence of residual deformation, it is difficult to model rheological behaviors. Especially, it is hard to accurately reproduce both rheological force and residual deform...

Humans mainly use their fingertips to explore and manipulate objects in daily life. When the fingertip comes in contact with an object, the mechanoreceptors beneath the skin respond to the deformation of skin and generate electrical impulses sent to the brain. However, the mechanical state at receptor locations is not empirically observable with th...

Rheological object, such as clay, various food products, biological organs and tissues, has both elastic and plastic properties. Modeling of such objects has not been studied intensively comparing with elastic objects. Previous rheological models were mostly based on linear constitutive law of stress and strain, which is limited to small deformatio...

The rheological properties of food products related to their engineering and manufacturing were modeled and estimated. A 2D/3D dynamic FE model for the simulation of uniform objects was formulated based on a five-element physical model and was further extended to deal with nonuniform layered objects. Three kinds of food materials (Japanese sweets)...

Rheological objects, such as some human organs or tissues, various food products, and cloth, demonstrate complex deformation behaviors, which consist of both elastic and plastic properties. Due to the presence of residual deformation, modeling of rheological objects is a challenging work, especially simultaneous reproduction of both rheological for...

Traditional Japanese sweets have long history and intense cultural background. In order to automate the manufacture process and also hand down the skillful techniques of sweets making, it is necessary to investigate the mathematical models of such objects and estimate their physical properties. This paper introduced a five-element physical model to...

We have developed a new model to simulate contact and rolling motion between two soft fingers and an object by using Finite Element and Constraint Stabilization Methods. This model is more efficient than the penalty method in connecting boundaries of objects through discrete models such as finite element models and particle models. We show the vali...

Many deformable objects in our living life demon-strate rheological behaviors, such as human organs and tissues, clays and various food products. Rheological objects include both elastic and plastic properties. Due to the presence of residual (permanent) deformation, it is difficult to model rheo-logical objects, especially to reproduce both force...

There are many kinds of deformable objects in our living life. Some of them such as human tissues, human organs, and food exhibit rheological behaviors when they are subject to external force. In surgery simulation and food engineering, we need to simulate or control such behaviors. In this paper, four-element model associated with finite element (...

Human tissues and organs often exhibit rheological behaviors during their deformation. For surgery simulation and human modeling, we have to identify physical parameters of such deformation in advance. In this paper, we propose an approach to estimate the physical parameters of uniform rheological deformation based on 2D/3D finite element (FE) mode...

Identification of physical parameters for soft objects is very important for surgical simulation, human modeling and food engineering. This paper presented a method to identify the physical parameters of uniform rheological deformation based on ID FE model simulations. Firstly, the real parameters were given to the model and simulations were done....

In order to research endo-atmospheric mass moment control interceptor with three moving mass actuators, dynamics equations of this system are derived in detail. The dynamics model with nine degrees-of-freedom is presented. Then the integrated simulation is performed using SIMULINK without neglecting any control parameters. The important factors of...

There are many kinds of deformable objects in our living life. Some of them demonstrate rheological behaviors during deformation, such as food, clay, human tissues, and organs. Usually, finite element (FE) model was employed to restructure or simulate the deformation behavior of such objects. However, there are important physical parameters to be k...