Towards Scalable Strain Gauge-Based Joint Torque Sensors

During recent decades, strain gauge-based joint torque sensors have been commonly used to provide high-fidelity torque measurements in robotics. Although measurement of joint torque/force is often required in engineering research and development, the gluing and wiring of strain gauges used as torque sensors pose difficulties during integration within the restricted space available in small joints. The problem is compounded by the need for a scalable geometric design to measure joint torque. In this communication, we describe a novel design of a strain gauge-based mono-axial torque sensor referred to as square-cut torque sensor (SCTS), the significant features of which are high degree of linearity, symmetry, and high scalability in terms of both size and measuring range. Most importantly, SCTS provides easy access for gluing and wiring of the strain gauges on sensor surface despite the limited available space. We demonstrated that the SCTS was better in terms of symmetry (clockwise and counterclockwise rotation) and more linear. These capabilities have been shown through finite element modeling (ANSYS) confirmed by observed data obtained by load testing experiments. The high performance of SCTS was confirmed by studies involving changes in size, material and/or wings width and thickness. Finally, we demonstrated that the SCTS can be successfully implementation inside the hip joints of miniaturized hydraulically actuated quadruped robot-MiniHyQ. This communication is based on work presented at the 18th International Conference on Climbing and Walking Robots (CLAWAR)

HyperDog: An Open-Source Quadruped Robot Platform Based on ROS2 and micro-ROS

Nowadays, design and development of legged quadruped robots is a quite active area of scientific research. In fact, the legged robots have become popular due to their capabilities to adapt to harsh terrains and diverse environmental conditions in comparison to other mobile robots. With the higher demand for legged robot experiments, more researches and engineers need an affordable and quick way of locomotion algorithm development. In this paper, we present a new open source quadruped robot HyperDog platform, which features 12 RC servo motors, onboard NVIDIA Jetson nano computer and STM32F4 Discovery board. HyperDog is an open-source platform for quadruped robotic software development, which is based on Robot Operating System 2 (ROS2) and micro-ROS. Moreover, the HyperDog is a quadrupedal robotic dog entirely built from 3D printed parts and carbon fiber, which allows the robot to have light weight and good strength. The idea of this work is to demonstrate an affordable and customizable way of robot development and provide researches and engineers with the legged robot platform, where different algorithms can be tested and validated in simulation and real environment. The developed project with code is available on GitHub (https://github.com/NDHANA94/hyperdog_ros2).Comment: 6 pages, 13 figures, IEEE SMC 2022 conferenc

Quadruped Robot with Inside Diagnostics

Cílem této práce je navrhnout čtyřnohý robot inspirovaný bioorganismy a vybavit jej senzory a výpočty pro vnitřní diagnostiku systému. Práce se zabývá konstrukčním návrhem mechanismu, kde většina konstruovaných dílů je určena pro výrobu na 3D tiskárně. Dále se zabývá specifikací hardwarových komponentů. Pro použitý mikrokontroler byla vyrobena rozšiřující deska plošných spojů pro připojení servomotorů. Senzorický subsystém robotu obsahuje detekci doteků noh, měření proudu, napětí akumulátoru a úhlů natočení těla robotu pomocí IMU. Práce popisuje tvorbu programů na PC a v robotu, použitou strukturu kódu a použité algoritmy. Robot komunikuje pomocí vlastního sériového protokolu. V robotu probíhají výpočty generování pohybu, inverzní kinematiky, polohy těžiště a detekce kolizí. Pro robot byl vytvořen simulační model v programu V-Rep, na kterém byly testovány použité algoritmy.The goal of this thesis is to design a quadruped robot inspired by bioorganisms and equip it with internal sensors. The thesis deals with mechanical design of the robot, where the majority of parts is designed for 3D printing. The thesis also deals with hardware specifications. An additional PCB has been manufactured to expand the capabilities of the used microcontroller. The sensory subsystem consists of foothold detection, current and voltage measurements and orientation detection using an IMU. The thesis describes development of the software for PC and the robot, used code structure and algorithms. The robot communicates using a custom serial protocol. Movement generation, inverse kinematics, center of gravity position and collision detection are all being calculated onboard the robot. A simulation model has been built in V-Rep, on which the used algorithms were tested.354 - Katedra robotikyvýborn

Kinematics analysis of a FLHL robot parallel-executed cylinder mechanical integration system with force/position hybrid control servo actuator

In this research subtopic, an electro-hydraulic servo four-legged heavy load (FLHL) robot has been designed and developed. This paper proposes an integration layout cylinder design scheme for a non-lightweight hydraulic servo four-legged robot with high loads and torques of hip joint, and derives the mathematical element analysis model for a parallel hydraulic servo cylinder system. The multiple inherent characteristics of the parallel-executed cylinder integration system model are further explored. Based on the controllable functional requirements of interconnected joints and weakening the influence of internal force coupling, a design idea of force/position hybrid control scheme for the parallel-executed cylinder is determined, and then the force/position signal module design unit is used to reversely solve the force/position hybrid control. Considering the inherent requirements of the servo-executed cylinder force control unit module, the implementation process of magnetic flux compensation and speed compensation is discussed in detail. The minimum amplitude controller is applied to the servo-executed cylinder force unit module, and the proportional integrated controller has been determined in the servo-executed cylinder position control unit module. A compound control strategy proposed in this paper is verified on a parallel hydraulic servo platform. The experimental verification results reveal that the values of position/force attenuation amplitude and lag phase are not greater than 9 % and 18°, respectively. In addition, the feasibility of the interconnected implementation of the hybrid control scheme proposed in this paper is further deepened. The effective conclusion of this research will be accepted in the application field of FLHL robot control system

The Fourteenth Scandinavian International Conference on Fluid Power, SICFP15: Abstracts

At this time the conference includes various themes like hybrids, drives, digital hydraulics and pneumatics. Special attention in the program is given for energy efficiency, renewable energy production and energy recovery. They are reflecting well the situation, where environmental issues and energy saving are increasingly important issues