Characterization of variable-sensitivity force sensor using stiffness change of shape-memory polymer based on temperature

In the present study, we propose a variable-sensitivity force sensor using a shape-memory polymer (SMP), the stiffness of which varies according to the temperature. Since the measurement range and sensitivity can be changed, it is not necessary to replace the force sensor to match the measurement target. Shape-memory polymers are often described as two-phase structures comprising a lower-temperature “glassy” hard phase and a higher-temperature “rubbery” soft phase. The relationship between the applied force and the deformation of the SMP changes depending on the temperature. The proposed sensor consists of strain gauges bonded to an SMP bending beam and senses the applied force by measuring the strain. Therefore, the force measurement range and the sensitivity can be changed according to the temperature. In our previous study, we found that a sensor with one strain gauge and a steel plate had a small error and a large sensitivity range. Therefore, in the present study, we miniaturize this type of sensor. Moreover, in order to describe the viscoelastic behavior more accurately, we propose a transfer function using a generalized Maxwell model. We verify the proposed model experimentally and estimated the parameters by system identification. In addition, we realize miniaturization of the sensor and achieve the same performance as in our previous study. It is shown that the proposed transfer function can capture the viscoelastic behavior of the proposed SMP sensor quite well

Turning motion generation of peristaltic crawling robot using two-dimensional dynamic model and numerical optimization

Peristaltic crawling robots inspired by the earthworm's motion have been attracting attention as robots for working in hazardous environments or confined spaces. The peristaltic crawling robots need turning motion to move in winding piping or in spaces with obstacles. In this study, we propose a model-based motion generation method for peristaltic crawling robots to realize a turning motion suitable for the robot’s dynamics and the friction characteristics of the environment. For realizing the motion generation, a two-dimensional dynamic model is constructed by combining the robot’s kinematics and a dynamic friction model, and motion patterns are generated by applying numerical optimization based on the particle optimization method. The contributions of this study are the construction of the model that enables detailed motion analysis on two-dimensional plane and the realization of the model-based method for generating efficient turning motions and turning movements at specified angles for peristaltic crawling robots. As a result of generating the turning motions, it was confirmed that the turning angle was increased by combining the stretching and bending motion. In addition, the validities of the constructed a two-dimensional dynamic model and motion generation method were confirmed from experimental verifications

IDC Robocon: A Transnational Teaming Competition for Project-Based Design Education in Undergraduate Robotics

This paper presents a robot design competition called ‘IDC Robocon’ as an effective tool for engineering education. The International Design Contest (IDC) Robocon competition has several benefits in creating a meaningful design experience for undergraduate engineering students and includes an international flavour as participants of the competition hail from all around the world. The problem posed to the contestants is to design, build and test mobile robots that are capable of accomplishing a task. A primary goal of the competition is to provide undergraduates with a meaningful design experience with an emphasis on mechanical design, electronic circuits and programming. It is hoped that by placing the emphasis on the design, the course will encourage more undergraduates to go into the field of engineering design. This paper presents the latest 2015 IDC Robocon (the 26th edition) in detail and discusses course of events and results in terms of the educational experience. In this competition, a simulated space problem of cleaning the debris from orbit is proposed for the latest IDC Robocon competition. Teams, comprising of students from multiple countries work together to develop robotic systems to compete with each other in collecting the foam balls and delivering them to the rotating the holder