This work introduces a digital-twin based approach to path planning in the presence of obstacles for a quadrupedal robot, utilizing virtual sensors and a path planning algorithm. Ray-casting and NavMesh agent-based algorithms are used to devise collision-free paths. The Ray-casting algorithm detects dynamic objects virtually, while the NavMesh system determines a feasible path for the robot. Real-time communication between the digital twin and the physical robot facilitates seamless movement. The effectiveness of this approach in enhancing the robot’s navigation and obstacle avoidance capabilities can be demonstrated through both simulated scenarios and real-world experiments. The implementation of the digital twin, along with the utilization of path planning and obstacle avoidance algorithms available in the Unity software, as well as the real-time integration with the physical robot, are significant contributions of this work. A shared environment is demonstrated for communications between robots, each with its own digital twin.

Constricted passages such as tubes may be out of the view of the robot vision system, and the wrist-force data may be useful in such cases. Collaborative robots (Cobots), which are equipped with precision wrist-force sensors, are suitable for sharing the workspace safely with human workers and other robots and devices. The data from the force sensor allows building more intelligent algorithms for robot control, and plan access to relatively unstructured obstacles. In this work, an attempt is made to model obstacles and constricted passages graphically for the digital-twin implementation of a collaborative robot and use the same for motion planning in the absence of vision sensors. The main scope of this work is to build the graphical framework for the digital twin and link the same with path planning algorithms in the public domain using MoveIt and Robot Operating System (ROS). Motion visualization is implemented using another software, called RViz. The co-simulation between MoveIt and RViz is, in turn, linked to the physical robot, or optionally, the simulation environment provided by the robot supplier.

This paper presents a prototype Automatic Guided Vehicle (AGV) equipped with two types of proximity sensors. Although largely modeled as a line-following robot, the algorithm makes reactive decisions based on sensory data to avoid the obstacles by temporaily deviating from the predefined path. The infrared (IR) sensors recognize the desired path of the AGV by detecting the high-contrast line on the surface, thus enabling automated motion of the AGV. The ultrasonic proximity sensors on the AGV aid in the detection of the obstacles or for following moving objects such as another AGV. Different scenarios are discussed where this multisensor capability enables enhanced perception for AGVs without resorting to a computationally more intensive robot vision system.

Collaborative Robots (Cobots) constitute a new class of industrial robot manipulators that are now becoming popular in tasks that require intelligent manipulation and human–robot interaction. The characteristic difference between these robots and the conventional industrial robots is the availability of force feedback from the wrist-force sensor. This allows the robot arm to avoid obstacles, detect variation in the part locations and estimate the type of objects being handled based on the weight or contact forces. Digital twin is the representation of a real-world object in a virtual environment. This allows the synchronization and replication of the motions of the robot present in the real world with that of the counterpart in a virtual environment and vice versa. This work is an initial attempt to develop a remote interface and a digital twin for a collaborative robot (Universal robot UR5e). Interfacing of the robot through Robotics Operating System (ROS) and the use of Unity3D for the development of the digital twin are reported here.

Soft robotics is an exciting new paradigm in engineering that challenges researchers to re-examine the materiials and mechanisms to make more versatile, life-like and bio-compatible actuator for human interaction. A wide class of materials come under t his category with the stimuli being heat, light, electricity or magnetism. However, the current interest in such materials focuses on achieving flex ible actuators which are amenable for easy processing. It provide the feasibility of smart actuating devices, that could undergo intelligent sh ape change and even biomimetic motion in response to external stimuli such as electric, thermal, photo etc. The goal of this work is to end ow robots with new, bio-inspired capabilities that permit adaptive and flexible interactions with unpredictable environments. We have investigated soft and fast-response actuators composed of a polymer base embedded with carbon na noparticles to exploit the excellent thermal response of certain CNPs. The study demonstrates that for a given type of polymer base, the m agnitude of the response can be significantly altered by the type of CNPs and concentration of CNPs. Large actuation has also been observed by incorporating CNPs made from bio-waste material.

Micro Electro Mechanical Systems (MEMS) is an emerging technique with an immense number of applications in aerospace and automobile industry. This innovation is advanced with the effective improvement in microelectronics. Sensors and actuators are the utilitarian components of MEMS; Sensor based MEMS are industrially accessible, while actuator based MEMS have a relative movement and thus not yet been marketed because of high friction (forces associated with Surface dominates the forces associated with volume) which prevents the smooth movement and reliability of the device. Additionally, the conventional material for MEMS devices is silicon (Si), which experiences poor tribological properties, and the tribology structures in the system are the main reason for the MEMS devices to fail. Hence tribology of MEMS devices requiring relative movement is of significance. In this situation, new microengineering approaches have been employed to decrease the occurrences of failures, numerous different techniques like thin film coatings, topographical and chemical modification, and application of dual-film coating have been evaluated to strengthen the device, relieve stiction, and thus reduce the friction and adhesion to the system structures. This paper presents an overview of above techniques to improve the performance of silicon surfaces in MEMS devices.

Visual odometry is a widely known art in the field of computer vision used for the task of estimating rotation and translation between two consecutive time instants. The RANSAC scheme used for outlier rejection incorporates a constant threshold for selecting inliers. The selection of an optimum number of inliers dispersed over the entire image is very important for accurate pose estimation and is decided on the basis of inlier threshold. In this paper, the threshold for inlier classification is adapted with the help of fuzzy logic scheme and varies with the data dynamics. The fuzzy logic is designed with an assumption about the maximum possible camera rotation that can be observed between consequent frames. The proposed methodology has been applied on KITTI dataset, and a comparison has been laid forth between adaptive RANSAC with and without using fuzzy logic with an aim of imparting flexibility to visual odometry algorithm.

When two robot systems can share understanding using any agreed knowledge, within the constraints of the system's communication protocol, the approach may lead to a common improvement. This has persuaded numerous new research inquiries in human-robot collaboration. We have built up a framework prepared to do independent following and performing table-best protest object manipulation with humans and we have actualized two different activity models to trigger robot activities. The idea here is to explore collaborative systems and to build up a plan for them to work in a collaborative environment which has many benefits to a single more complex system. In the paper, two robots that cooperate among themselves are constructed. The participation linking the two robotic arms, the torque required and parameters are analyzed. Thus the purpose of this paper is to demonstrate a modular robot system which can serve as a base on aspects of robotics in collaborative robots using haptics.

In this paper, the aim is to design and develop a bendable soft actuator prototype to overcome the limitations of Surgical Lighting Systems (SLS). Pneumatic bending actuator made of silicone rubber undergoes the desired deformation when each chamber is pressurized. Surgical luminaires are used for illumination of wounds during surgery. For optimal illumination surgical luminaries need to change their orientation several times during surgery. Soft actuator because of flexibility provides advantage to overcome the mechanical singularity faced by existing surgical lighting system. Mathematical model based on geometric deformation has been presented. A fourth degree polynomial approximation has been used for characterize behavior of each chamber of actuator.

Myoelectric or electromyogram (EMG) signals can be useful in intelligently recognizing intended limb motion of a person. This paper presents an attempt to develop a four-channel EMG signal acquisition system as part of an ongoing research in the development of an active prosthetic device. The acquired signals are used for identification and classification of six unique movements of hand and wrist, viz. hand open, hand close, wrist flexion, wrist extension, ulnar deviation and radial deviation. This information is used for actuation of prosthetic drive. The time domain features are extracted, and their dimension is reduced using principal component analysis. The reduced features are classified using two different techniques: k nearest neighbor and artificial neural networks, and the results are compared. ©2009 IEEE.

A springy-leg, offset-mass or SLOM hopper configuration is considered here, wherein the center of gravity of the body is offset from the line of action of spring force. It is observed that this feature tends to extend the passive hopping motion. A heuristics-based search strategy and a genetic algorithm-based search strategy are implemented for finding the initial conditions that result in extended hopping motion. Copyright © 2007 by ASME.

A kangaroo-like hopping machine with a mass-less springy leg, a body with centre of mass offset from the line of action of the spring find a tail link has been investigated in this study. Equations of motion in stance and flight phases are presented in this article. The equations determining the jump in velocities at the instant of touchdown are also formulated, based on impulse equations. The model has been used to simulate hopping motion for some select sets of parameters and initial conditions. Such a model can be used to develop largely passive, underactuated hopping systems, where relatively small actuators may suffice to compensate for the energy losses and to correct any deviations from a largely passive hopping trajectory.

When an object is made using Laminated Manufacturing (LM), the output is a rectangular block with the required object trapped inside. In order to enable extraction of the object, the remaining sheet in each layer is cut into square grids that grow into tiny tiles. Thus, the remaining stock inside and surrounding the object is in the form of tiled fragments. The operator 'decubes' or removes these tiles using sharp tools and extracts the object. Making use of the remaining stock as support structure and grid cutting to enable extraction of the object are very innovative ideas in the 'paste-and-cut' LM approach. However, this method is very inefficient for two reasons: firstly, cutting efficiency is poor since laser spends most of its time in grid cutting; secondly, decubing takes several hours. In this paper, an efficient method of cutting the remaining stock to extract the object is presented. Extraction of the object from the stock block has analogy with the extraction of casting from its mold - the present and proposed methods respectively being analogous to sand casting and permanent mold casting processes. In the proposed method, rather than fragmenting the remaining stock into tiny tiles, it is segmented into two stock halves that open about a parting surface of minimum area. This optimal parting surface is obtained for the convex hull of the object, rather than for the object itself, due to its complete visibility along any pair opposite directions. The convex hull is further segmented into the object and plugs. The plugs are so shaped that they do not get entangled inside the concave portions of the object. The plugs whose drawing directions coincide with the opening direction of the stock halves are merged with the corresponding stock halves. The object, all the plugs and both the stock halves form the stock block. All these pieces are made together in the LM machine. For disassembly, first the convex hull will be extracted by opening the stock halves. Subsequently the plugs that fill the concave portions of the object will be extracted from the convex hull. Thus, grid cutting and decubing are eliminated in the proposed method resulting in drastic reduction in prototyping time and improved quality of the prototype. © 2002 Elsevier Science Ltd. All rights reserved.

Calculation of the swept volume of a cutter is the heart of any numerical controlled (NC) simulation system NC machining, a wide variety of cutter shapes are used such as flat end mills, dome end mills, ball nose end mills, angle cutters, face mills and side-and-face cutters. There are also many types of cutter paths along which the cutter is guided by the NC controller: rapid motion, linear motion and circular motion are the most commonly used cutter paths among them. Furthermore, the kinematics of the NC machines also differ leading to 2.5-axis, 3-axis and a variety of 5-axis configurations. The swept volume algorithms have to take into account all these variations of cutter shapes, motion types and machine kinematics this paper, first the parametric definition of a generic cutter is presented that can emulate all types of cutter shapes. Subsequently, the motions are classified into six types considering the cutter path and kinematic variations for ease of swept volume calculations. Finally, the swept volume algorithms for each of these six motion types are presented. These algorithms are used in a volumetric NC simulation system for which applications are envisaged in (a) NC verification and (b) optimization of the feed rate. © IMechE 2000.

Even as several rapid prototyping processes are emerging that can build metallic and ceramic tools directly from slices, this new manufacturing concept continues to suffer from high cost and poor accuracy primarily due to uniform slicing and staircase effect. To surmount this problem, a new RP process that makes use of adaptive slicing with first order approximation of the edges is proposed. In manufacturing, one uses a fast roughing process followed by one or more finishing processes that are slow but accurate. The methodology adopted in the proposed RP process also uses this concept of two-level processing, viz., near-net building of the layer and net-shaping it by high-speed machining. This new methodology, which is at conceptual stage, would result in faster prototypes with better accuracy.

At the completion of building an object in laminated object manufacturing rapid prototyping (LOM-RP), a block with the required object inside is obtained. The remaining stock inside and surrounding the object is in the form of tiny tiles. The operator 'decubes' these tiles using sharp tools and extracts the object. After cutting the object contours in each laminate during the building process, the remaining sheet is cut into square grids that grow into these tiles. This grid cutting method, though very simple and innovative, is very inefficient due to poor cutting efficiency and a long decubing time. In this paper, a novel method is presented for extracting the object that is analogous with the extraction of a casting from its permanent mould. This method has a very high cutting efficiency and simplifies and speeds up decubing. The concepts of convex hull and visibility are utilized in the algorithm.