Amir Shapiro

Ben-Gurion University of the Negev | bgu · Department of Mechanical Engineering

Biomechanical energy harvesters are designed to generate electrical energy from human locomotion (e.g., walking) with minimal or no additional effort by the users. These harvesters aim to carry out the work of the muscles during phases in locomotion where the muscles are acting as brakes. Currently, many harvesters focus on the knee joint during la...

Sensors, Special Issue: "Mobile robots for navigation" This Special Issue will focus on mobile-robot or robots warm navigation systems, mobile robot SLAM, and realtime 3D motion planning, at all levels of abstraction. We welcome original, state-of-the-art studies in the areas that contribute to academia and industry. The Special Issue will cover,...

Introduction The inability to recover from unexpected lateral loss of balance may be particularly relevant to the problem of falling. Aim We aimed to explore whether different kinematic patterns and strategies occur in the first recovery step in single-step trials in which a single step was required to recover from a fall, and in multiple-step tri...

One of the most crucial parts of manufacturing is fixing the workpiece. Proper fixturing enables accurate machining, assembly, etching, etc. Most modern fixturing devices are static and difficult to adapt to varying workpieces. This letter introduces a new concept for a fixturing device–the SIMJig–that automatically adapts its structure to fix a gi...

Impairment in force regulation and motor control impedes the independence of individuals with stroke by limiting their ability to perform daily activities. There is, at present, incomplete information about how individuals with stroke regulate the application of force and control their movement when reaching, grasping, and lifting objects of differ...

Introduction—The inability to recover from unexpected lateral loss of balance may be particularly relevant to the problem of falls. Aim—We aimed to explore whether different kinematic patterns and strategies occur in the first recovery step in single-step trials when single step was required to recover from fall and in the multiple-step trials, whe...

The involvement of Robots and automated machines in different industries has increased drastically in recent years. Part of this revolution is accomplishing tasks previously performed by humans with advanced robots, which would replace the entire human workforce in the future. In some industries the workers are required to complete different operat...

The aim of this article is to present the fuzzy Petri net algorithm and its implementation on the Guide d’etude des modes de marche et d’arrêt (GEMMA) guide paradigm. Additionally, this article presents a brief description of the GEMMA guide paradigm, the fuzzy logic approach, the Petri nets theory, and fuzzy Petri nets. Each algorithm is intended...

This article presents a deep reinforcement learning-based controller for an unmanned ground vehicle with a custom-built scooping mechanism. The robot’s aim is to autonomously perform earth scooping cycles with three degrees of freedom: lift, tilt and the robot’s velocity. While the majority of previous studies on automated scooping processes are ba...

Background Balance control, and specifically balance reactive responses that contribute to maintaining balance when balance is lost unexpectedly, is impaired in older people. This leads to an increased fall risk and injurious falls. Improving balance reactive responses is one of the goals in fall-prevention training programs. Perturbation training...

Background: Step-recovery responses are critical in preventing falls when balance is lost unexpectedly. We investigated the kinematics and strategies of balance recovery in older adults with a varying history of falls. Methods: In a laboratory study, 51 non-fallers (NFs), 20 one-time fallers (OFs), and 12 recurrent-fallers (RFs) were exposed to...

A major challenge in designing technologies that are intended to work in direct contact with humans lies in achieving maximal coordination between the human and the technological device (robot), while minimizing interference with or restraint of the normal human behavior. This is particularly relevant to systems designed to assist in human walking....

Piezoelectric elements (PEMs) are used in a variety of applications. In this paper we developed a full analytical model of a piezoelectric actuator which includes piezostack elements and a three-stage amplification mechanism. The model was derived separately for each unit of the system. Next, the units were combined, while taking into account their...

Modern robotic grippers are either specialized and simple, complex and general purpose, or soft and compliant hands. The first provide high reliability but are limited in the range of objects they grasp. Compliant or soft grippers can grasp wide ranges of objects, but are not yet reliable enough for real-world applications. This paper presents a no...

Introduction: Many falls in older adults occur during walking and result in lateral falls. The ability to perform a recovery step after balance perturbation determines whether a fall will occur. Aim: To investigate age-related changes in first recovery step kinematics and kinematic adaptations over a wide range of lateral perturbation magnitudes...

Successful grasping of objects with robotic hands is still considered a difficult task. One aspect of the grasping problem is the physical contact interaction between the robotic fingertips and the object. Friction at the fingertip contacts can improve grasp robustness, but frictional fingertips may be difficult to precisely place on the object's p...

In this paper a high accuracy position control strategy for a pneumatic actuation system subjected to a varying external force is proposed. A novel approach for the mathematical modeling of the pneumatic actuator, based on energy methods, is presented. The Lagrangian is derived from combining the kinetic and potential energies, leading to formulati...

In this work, we suggest a novel solution to a very specific problem - calculating the pose (position and attitude) of a micro-aerial vehicle (MAV) operating inside corridors and in front of windows. The proposed method makes use of a single image captured by a front facing camera, of specific features whose three-dimensional (3D) model is partiall...

Caging offers a robust strategy for grasping objects with robot hands. This letter describes an efficient caging-to-grasping algorithm for polygonal objects using minimalistic three-finger robot hands. This letter describes how to cage and then grasp polygonal objects, using single actuator triangular three-finger formations, whose shape is determi...

Compliant grasping systems offer a wide range of robot hand designs. Understanding the stability behavior of compliant grasps can enhance the reliability and security of such hands. A classical result in compliant grasp mechanics states that a stable multifinger grasp can suddenly lose its stability when the finger force magnitudes exceed a critica...

Understanding human balance is a key issue in many research areas. One goal is to suggest analytical models for the human balance. Specifically, we are interested in the stability of a subject when a lateral perturbation is being applied. Therefore, we conducted an experiment, laterally perturbing five subjects on a mobile platform. We observed tha...

The purpose of this study was to evaluate the inter-observer reliability and agreement of balance recovery responses, step and multiple-steps thresholds, and kinematic parameters of stepping responses. Older and younger adults were exposed to 36 progressively challenging right and left unannounced surface translations during quiet standing. Subject...

An approach to predict the workpiece accuracy in 5-axis machining based on the standard acceptance conditions for machining centers (ISO 230-1) is introduced. The end-user should be able to verify the machine tool accuracy performances in advanced to the purchasing stage and prevent false buying decisions as well as non-relevant expensive machining...

Background Rapid compensatory stepping plays an important role in preventing falls when balance is lost; however, these responses cannot be accurately quantified in the clinic. The Microsoft Kinect™ system provides real-time anatomical landmark position data in three dimensions (3D), which may bridge this gap. Methods Compensatory stepping reaction...

Human gait is symmetric and bilaterally coordinated in young healthy persons. In the present study we aimed to explore differences in bilateral coordination of gait as measured by the Phase Coordination Index (PCI), Gait Asymmetry (GA) and stride time variability of gait between 4 age groups. Forty-four older adults were recruited: nine young old (...

Almost any task on an object requires regrasping of the object prior to performing an intended task by varying between grasp configurations. The human hand uses many methods to perform regrasping manipulations such as in-hand sliding, finger gaiting, juggling, picking and placing, etc. The most complex and inspiring approach is the in-hand orientin...

We present a new image based visual servoing (IBVS) approach for control of micro aerial vehicles (MAVs) in indoor environments. Specifically, we show how a MAV can be stabilized and guided using only corridor lines viewed on a front facing camera and angular velocity measurements. Since the suggested controller does not include explicit attitude f...

This paper suggests a novel method for a mobile robot to plan its path towards a target through an unknown environment, using sensors to discover new obstacles along the way. The method synthesizes an artificial temperature gradient throughout the known environment by numerically solving the heat conduction partial differential equation, where obst...

Multi-finger caging offers a robust object grasping approach.While efficient computation of two-finger caging grasps is well developed, the computation of three-finger caging grasps has remained a challenging open problem. This paper considers the caging of polygonal objects with three-finger hands which maintain an equilateral triangle formation d...

Acquiring a qualitative force-closure grasp requires the determination of feasible contact points on the object based on a defined criterion. The determination must be fast in order to implement feasible synthesis algorithms. Moreover, grasping of sheet metal parts has further requirements derived from its geometry and clamping tools. This paper pr...

A simple gripper for a robotic arm capable of grasping various objects in manufacturing lines provides great benefits in terms of standardization of grippers, reducing engineering time and costs. This will provide the possibility to reuse the manufacturing line for several products of different geometry without significant changes. The goal is to m...

In robotics, knowing a mechanism’s configuration is essential. Commonly, potentiometers or encoders are used in order to obtain the mechanism’s configuration. Nevertheless, such sensors are useless for applications were a surface’s spatial-shape is to be attained. For that end we introduce a novel sensor mesh. We use an electricalresistors grid as...

In this paper, we present the swing-up regrasping problem in which an object is manipulated using a robotic arm around a point pinched by the arm's gripper. The aim of the regrasping is to manipulate the object from an initial angle to regrasp it on a new desired angle relative to the gripper. The pinching point functions as a semiactive joint at w...

The fabrication of a multiactuator mechanism requires excessive wiring that may become the design's bottleneck. We introduce a novel actuation method for an actuated flexible manifold (AFM). The AFM is a 2-D surface embedded in ℝ2 or ℝ3. The AFM shape can theoretically be manipulated into any continuous smooth function. The mechanism possesses doze...

This work is motivated by the lack of manpower to perform vineyard spraying tasks and the exposure to hazardous pesticides during the spraying. The development of an autonomous system for vineyard spraying would reduce the amount of required labour and redirect it to performing tasks that could increase the farm yield and agricultural profitability...

We developed a biomechanical device, designed to generate electrical energy from human locomotion (e.g. walking). The device aim at generating energy with minimal effort, by replacing part of the muscles work during the phases in human motion where the muscles act as brakes (i.e. negative work). The addition of effort is due to two main factors: th...

Falls are common among elderly, most of them occur while slipping or tripping during walking. We aimed to explore whether a training program that incorporates unexpected loss of balance during walking able to improve risk factors for falls. In a double-blind randomized controlled trial 53 community dwelling older adults (age 80.1±5.6 years), were r...

Stepping or crawling translation manoeuvres are computationally complicated when applied to hyper-redundant mechanisms. We introduce a motion planner for a novel polyhedron-shaped Actuated Flexible Manifold (AFM). The AFM is a two-dimensional closed or open surface embedded in . The AFM can reshape itself up to a given radius of curvature at any g...

Recent years show an increasing interest in flexible robots due to their adaptability merits. This paper introduces a novel set of hyper-redundant flexible robots which we call actuated flexible manifold (AFM). The AFM is a two-dimensional hyper-redundant grid surface embedded in R2 or R3. Theoretically, such a mechanism can be manipulated into any...

A novel approach for control of a Micro Air Vehicle in indoor environment (specifically within corridors) using only vision and angular velocity sensors as measuring devices is presented. The suggested controller does not include explicit attitude feedback, thus eliminating the need for accelerometers which are susceptible to vibrations, and comple...

Apparatus for exercising a person's balance control, the apparatus comprising: a motion stage operable to displace an object mounted thereto; a treadmill mounted to the stage and comprising a belt having a runway surface on which a person using the treadmill stands, walks and/or runs; and a controller that controls the motion stage to provide a dis...

We study the effects of tilting the plane of rotations of the rotors of a quadrotor helicopter inwards, a structure inspired by the dihedral angle in fixed-wing airplanes. We show that this configuration yields effects that contribute to stability and reduce the dependency on velocity measurement which, in many cases, is hard to achieve at sufficie...

In the EU-funded CROPS project robots are developed for site-specific spraying and selective harvesting of fruit and fruit vegetables. The robots are being designed to harvest crops, such as greenhouse vegetables, apples, grapes and for canopy spraying in orchards and for precision target spraying in grape vines. Attention is paid to the detection...

This paper presents the design of a novel quadruped robot. The proposed design is characterized by a simple, modular design, and easy interfacing capabilities. The robot is built mostly from off-the-shelf components. The design includes four 3-DOF legs, the robot body and its electronics. The proposed robot is able to traverse rough terrain while c...

This paper addresses the problem of defining a simple End-Effector design for a robotic arm that is able to grasp a given set of planar objects. The OCOG (Objects COmmon Grasp search) algorithm proposed in this paper searches for a common grasp over the set of objects mapping all possible grasps for each object that satisfy force closure and qualit...

The form-shaping function (FSF) approach presents an effective tool for design optimization of machine structures and machining processes, evaluation and compensation of geometric and kinematic errors and development of the postprocessors for multi-axis machine tools. In this work, the FSF approach is enhanced with the aim of embedding the stiffnes...

We propose a computational scheme for solving the robust output-feedback H∞ control problem, for a class of nonlinear systems with polynomial vector field. By converting the resulting Hamilton-Jacobi inequalities from rational forms to their equivalent polynomial forms, we overcome the non-convex nature and numerical difficulty. Using quadratic Lya...

We present a novel generic tool to design the shape and location of an actuator for continuous elastic dynamic systems, i.e. essential properties of the actuators in order to generate a desired state profile. The main idea of the research is to generate an approximation via reduction of the number of actuators by using the singular value decomposit...

Destructive results of natural disasters like the earthquake in Japan are not subject to control. Fukushima catastrophe has shown that for now, robots do not have human capabilities when it comes to search and rescue. At time of writing this paper a robotics competition takes place whose goal is promoting research on issues related to operation of...

We propose a computational scheme for solving the output-feedback H∞ control problem, for a class of nonlinear systems with polynomial vector field. By converting the resulting Hamilton-Jacobi inequalities from rational forms to their equivalent polynomial forms, we overcome the non-convex nature and numerical difficulty. Using quadratic Lyapunov f...

This paper proposes a position control strategy for a pneumatic actuation system, which demonstrates high accuracy while it is subjected to a varying external force. We use a novel approach for the mathematical modeling of the pneumatic actuator: based on energy methods, we combine the kinetic and potential energy to derive the Lagrangian of the ac...

In this paper, a novel computational scheme is proposed in order to solve the output-feedback H ∞ control problem for a class of nonlinear systems with polynomial vector field. By converting the resulting Hamilton-Jacobi inequalities from rational forms to their equivalent polynomial forms, we overcome the non-convex nature and numerical difficulty...

This work proposes an algorithm for designing a simple End Effector configuration for a robotic arm which is able to grasp a given set of objects. The algorithm searches for a common 3-finger grasp over a set of objects. The search algorithm maps all possible grasps for each object which satisfy a quality criterion and takes into account an externa...

This paper presents an algorithm for planning the foothold positions of quadruped robots on irregular terrain. The input to the algorithm is the robot kinematics, the terrain geometry, a required motion path, as well as initial posture. Our goal is to develop general algorithm that navigate quadruped robots quasi-statically over rough terrain, usin...

This paper presents the design of a novel robot capable of climbing on vertical and rough surfaces, such as stucco walls. Termed CLIBO (claw inspired robot), the robot can remain in position for a long period of time. Such a capability offers important civilian and military advantages such as surveillance, observation, search and rescue and even fo...

We present a novel generic tool to design the shape and location of an actuator for continuous elastic dynamic systems, i.e. essential properties of the actuators in order to generate a desired state profile. The main idea of the research is to generate an approximation via reduction of the number of actuators by using the singular value decomposit...

In this paper we present a novel design for a dual-tracked mobile robot. The robot is designed for safe, stable, and reliable motion in challenging terrains, tunnels, and confined spaces. It consists of two tracked platforms connected with a semipassive mechanism. Sensors attached to the connecting mechanism provide redundant localization data that...

Grasping mechanisms (grippers) are used for a wide range of applications including fixturing arrangements, industrial, agricultural, and service robotics for medical and home use. The gripper must immobilize the object it is manipulating, while applying the minimal necessary grasping force, in order to prevent the grasped object’s bruising. Perform...

We explore the problem where a group of robots with different velocities search for a target in an unbounded unknown environment. The target position is un known, hence, an online search algorithm is developed. The H-MRSTM algorithm (Heterogeneous Multi-Robot Search Time Multiplication), launches a group of n robots from a common starting location...

SpiderBot is a cable suspended mobile robot that is designed to climb walls and hang from ceilings by shooting tethered plungers onto the surface. Removing the plungers, it reels in the web, aims, and repeats the process to climb farther. SpiderBots' design was inspired by the fictional character Spider-Man. The robot can be used for carrying equip...

Biomechanical energy harvesting from human motion presents a promising clean alternative to electrical power supplied by batteries for portable electronic devices and for computerized and motorized prosthetics. We present the theory of energy harvesting from the human body and describe the amount of energy that can be harvested from body heat and f...

In this paper we consider grasps and fixtures whose contacts react according to force—displacement laws consistent with friction constraints at the contacts. The passive force closure set of such grasps and fixtures is the set of external wrenches (forces and torques) that can act on the grasped object and be stably balanced by the contacts. An ext...