Haptic Mechanism Research Articles

Dynamic Analysis and Design of an SMCNN of a 6-DOF Parallel Mechanisms using Translation Driver Motor

—Recently, many technological improvement apply in the discovery of various designs of haptic devices. Several mechanism structures including serial, parallel, and hybrid-kinematic manipulators can be considered for making a haptics device. The most successful haptic mechanisms are parallel-type, because of low moving inertia, large force reflection, and high stiffness. This research shows the 6-DOF parallel haptics device based on the parallel mechanism using a translation driver motor mounted on each leg. Firstly, we introduce a 6-DOF parallel mechanism using a translation driver motor haptics device model. Due to the unsure parameters, we focus on solving the mathematics model with the nonlinear parameters of the 6-DOF parallel mechanism. Secondly, to fix the kinematics and dynamics nonlinear uncertainties parameters, the SMCNN controller for 6-DOF parallel mechanism application using a translation driver motor is designed. The Sliding model control base on artificial intelligence neural network is used to calculate the unsure factors. In this technique, to prove the stability of the system the Lyapunop theory is used. Finally, the authors the simulation results of two control algorithms with different uncertain components are presented and comparing them to demonstrate the effectiveness of the new control method. The control method is demonstrated by way of implementing the set of rules in artificial surroundings with realistic parameters, in which the received consequences are fairly promising. The obtained from SMCNN algorithm results are highly promising and accurate.

A novel hand exoskeleton to enhance fingers motion for tele-operation of a robot gripper with force feedback☆

This research describes a robotic system's design, optimization, and implementation processes for tele-operation with haptic feedback using the Hand Exoskeleton of New technologies research center (HEXON) as a novel haptic mechanism and the HEXON robotic gripper to work collaboratively with the exoskeleton. In particular, a force-sensitive robotic gripper is connected to a hand exoskeleton, mimics the user's hand movements, and transfers haptic feedback through the exoskeleton. The two-finger exoskeleton's design process consists of a multi-criteria optimization procedure to simultaneously maximize applied force to the finger and workspace of the attached exoskeleton, optimizing both the Perpendicular Impact Force (PIF) and the Global Isotropy Index (GII), considering worst-case collision avoidance. Due to the tele-operation application and using a robotic arm as a slave in the remote scenario, the gripper can be used as an end-effector for a palletizing 3-DOF robotic arm, and movement of the gripper can be achieved by using a visual sensor to pinpoint the user's hand location in 3D space. With the aim of the stress analysis software, the exoskeleton and gripper designs were analyzed to evaluate the system strength against applied forces. Finally, based on the achieved results, the gripper and two-fingered exoskeleton prototypes were fabricated. Simulations and experimental results are reported, showing the potential of the HEXON in haptics and tele-operation applications, and the exoskeleton is used to operate a robotic arm and gripper while the user can perceive the objects virtually.

Time efficient stiffness model computation for a parallel haptic mechanism via the virtual joint method

Haptic devices are used for displaying a range of mechanical impedance values to the user. This impedance is regulated by a real-time control loop depending on the position information of the end-effector, which is usually acquired indirectly by using forward kinematics equations. Nevertheless, the kinematic model is insufficient to obtain accurate values if there are non-negligible compliant displacements. This gives a strong motivation for implementing a real-time stiffness model in the haptic control loop for improving its accuracy. Additionally, stiffness performance indices can be used at the design stage for enhancing the haptic devices impedance range within optimal design procedures. Fast solutions of a stiffness model are required for a real-time control as well as for decreasing the optimization time during a design process with a trade-off between accuracy and computational costs. In this study, we propose a computation time-efficient stiffness analysis of a parallel haptic device mechanism. The accuracy and computational costs of the proposed model are calculated and compared with a model that is obtained via a finite element method to demonstrate the effectiveness of the proposed approach with the desired real-time and accuracy performance.

Mechatronic design and implementation of a bicycle virtual reality system

The aim of this study is to design and implement a virtual reality bicycle system based on a functional-based mechatronic design approach. The development of virtual reality technologies with haptic systems demands a proper integration of the involved disciplines to provide immerse experiences for users. The proposed design approach provides a formal manner to gather the subsystems in the mechatronic device. The developed system is divided in a Virtual Reality System (VRS) and a Physical System (PS) for the design process. The former includes an interactive virtual environment in which an Avatar is animated using a simple kinematic bicycle model. The latter includes an adapted mountain bicycle with haptic feedback mechanisms to interact with the user and to produce the corresponding inputs for the bicycle model. Both systems are integrated by a control behavior system that works under two operation modes, where the user carries out virtual tours and gets feedbacks from a stereoscopic display system, audio cues, and haptic mechanisms. A multibody simulation validates the consistency and the integration of the physical system. In addition, a set of experimental results show the performance of instrumentation elements, control strategies, and feedback mechanisms, to provide the user with an immersive experience in the virtual environment. A brief survey was carried out to assess the opinion of users about the virtual bicycle tours, providing feedback for future improvements. The different designed modules and sub-systems allow modifying and enhancing the VRS without major modifications of the PS, or allow enhancing the physical platform without affecting the functionality of the virtual environment.

Robotic Arm with Built-in Haptic AR Mechanism for Force Sense Training underVarious Position

Robotic Arm with Built-in Haptic AR Mechanism for Force Sense Training underVarious Position

Application of the principle of energy equivalence to obtain suitable models of parallel planar mechanisms for identification including friction parameters. A case study: 5R RePlaLink haptic mechanism

It is important for the mechatronic design of robotic systems to rely on accurate models. To that end, system identification methods are a convenient tool to obtain the values of the unknown dynamic parameters which play a key role. In this paper, it is investigated the application of the principle of energy equivalence to easily obtain a suitable model for identification of the inertial parameters and friction of planar mechanisms. The methodology here proposed is then applied to the prototype RePlaLink, a 5R haptic mechanism. Experimental data was obtained to carry out the identification, and the results were then validated by using a different trajectory than the one used for the identification of the unknown parameters. It was found that the identified model developed for the mechanism using the herein described methodology, was able to predict the dynamic behavior of the mechanism.

Design of a novel 6-DOF haptic master mechanism using MR clutches and gravity compensator

This work presents design and dynamic analysis results of a novel 6-degrees-of-freedom (6-DOF) haptic master mechanism featured by magneto-rheological (MR) devices and gravity compensator. The design target of the haptic master mechanism is determined on the basis of the possible application to the robotic-assisted minimally invasive surgery (RMIS) system in which a certain magnitude of the force or moment is required to feel by the surgeon. The dynamic torque/force models associated with MR clutches and brakes are derived considering the geometry and Bingham characteristics of MR Fluid. In the mechanism geometry, the wrist part is designed with a symmetrical structure such that the center of gravity is at the center of the handle. This makes the dynamic model of the proposed mechanism to be decoupled between the wrist motion and the translation motion. In addition, a gravity compensator is designed to enhance tracking performances of the desired repulsive forces/torques. It is demonstrated that the proposed 6-DOF MR haptic master can sufficiently generate desired rotational and translational forces/torques required in RMIS system.

Roughness discrimination with bio-inspired tactile sensor manually sliding on polished surfaces

As an important application of tactile sensing, the capability of texture discrimination is desired in many researches, such as artificial limbs, dexterous manipulation, and humanoid haptic mechanism, etc. In this research, a bio-inspired tactile sensor containing two perpendicular sensing films was developed and manually controlled to slide across 15 polished surfaces with different roughness. Algorithms of discrete wavelet transform (DWT), sequential feature selection (SFS) and extreme learning machine (ELM) were combined together to form a signal processing system for signal decomposition, feature selection and roughness discrimination respectively. Factors affecting roughness discrimination accuracy were evaluated and compared with human tactile sensing capability. Particularly, influences of starting point and sliding duration on discrimination accuracy were analyzed to identify the optimal signal period for the following analysis. Effects of sampling rate on the discrimination accuracy were then investigated using the ELM classifier. Another two typical classification models, k-nearest-neighbor (kNN) and support vector machine (SVM), of different parameter configurations were compared with ELM in surface roughness discrimination. Results showed that the developed method based on manual sliding of the developed tactile sensor is capable of providing a surface roughness discrimination accuracy of 72.93 ± 10.48% with the real polished surfaces.

Real time device control over voice recognition inoffline

The consistent increase in the number and ownership population of mobile devices introduces a variety of limitations. A set of this limitations revolve around interactivity. The overly dependent haptic mechanism of interaction has caused device falls, slower time to interaction, health concerns, and limited support for the disabled among other problems. There is need to formulate innovative techniques that facilitate our interaction with these devices for users. In order to achieve this, a Real-time Voice Recognition Algorithm is formulated that lets users of mobile devices acquire freedom to move about and reduce the need for constantly glancing at their screen. This is achieved by allowing users to verbally command their devices to carry out ordinary tasks. An added unique feature is that it also offers offline access as any commands given by a user are processed and executed locally on the device.

Mechanism for Adaptive Virtual Reality Feedback1

This work presents development and testing of two haptic mechanisms to simulate epidural needle insertion procedure. To configure the force feedback accuracy, we measured 20 insertions from patients in-vivo during a clinical trial. The graphics and forces adapt to the BMI of individual patients. Two haptic mechanisms were constructed: An electromagnetic haptic device (Fig. 1) and a motor driven haptic device (Fig. 2.). The resulting closed-loop system comprises manikin using four sensors and three force feedback components which can connect to our developed virtual reality epidural simulator 3D computer graphics [1]. Our literature review identified that thirty one epidural simulators have been implemented for clinical practice over the last thirty years either commercially or for research [2]. The purpose of this mechanism is to: i) connect the manikin device to computer based virtual reality graphics, ii) model insertions on various BMIs, iii) use measured data driven approach, iv) track needle orientation and depth using sensors, v) model accurate loss-of-resistance (LOR) feeling, vi) saline should escape at loss of resistance, vii) different feeling for each tissue layer, viii) mimic cerebrospinal fluid (CSF) leak on dural puncture.

Design of multi-degree motion haptic mechanisms using smart fluid-based devices

ABSTRACTThis article presents two different types of haptic masters capable of 4-degree- of-freedom (DOF) force feedback utilizing magnetorheological fluid (MR) and electrorheological (ER) fluid. The proposed ER master consists of a spherical joint for 3-DOF rotational motion and a linear device for 1-DOF translational motion, the MR haptic master consists bi-directional clutches associated with a planetary gear system and one-directional clutch with a bevel gear system. After showing the configuration of each haptic mechanism, the torque and force models of the actuators are derived based on the field-dependent Bingham model. After undertaking optimal design with spatial limitation and desired torque level, two different types of haptic master systems are manufactured. The torque and force responses are experimentally evaluated to validate practical feasibility of the proposed haptic masters for medical application.

Hand Rehabilitation Learning System With an Exoskeleton Robotic Glove.

This paper presents a hand rehabilitation learning system, the SAFE Glove, a device that can be utilized to enhance the rehabilitation of subjects with disabilities. This system is able to learn fingertip motion and force for grasping different objects and then record and analyze the common movements of hand function including grip and release patterns. The glove is then able to reproduce these movement patterns in playback fashion to assist a weakened hand to accomplish these movements, or to modulate the assistive level based on the user's or therapist's intent for the purpose of hand rehabilitation therapy. Preliminary data have been collected from healthy hands. To demonstrate the glove's ability to manipulate the hand, the glove has been fitted on a wooden hand and the grasping of various objects was performed. To further prove that hands can be safely driven by this haptic mechanism, force sensor readings placed between each finger and the mechanism are plotted. These experimental results demonstrate the potential of the proposed system in rehabilitation therapy.

Design and Control of a Haptic Enabled Robotic Manipulator

Robotic surgery offers various advantages over conventional surgery that includes less bleeding, less trauma, and more precise tissue cutting. However, even surgeons who use the best commercially available surgical robotic systems complain about the absence of haptic feedback in such systems. In this paper, we present the findings of our project to overcome this shortcoming of surgical robotic systems, in which a haptic-enabled robotic system based on master and slave topology is designed and developed. To detect real-time intrusion at the slave end, haptic feedback is implemented along with a programmable system on chip, functioning as an embedded system for processing information. In order to obtain real-time haptic feedback, force and motion sensors are mounted on each joint of the master and slave units. At the master end, results are displayed through a graphical user interface, along with the physical feeling of intrusion at the slave part. Apart from the obvious applications of the current system in robotic surgery, it could also be used in designing more intuitive video games with further precise haptic feedback mechanisms. Moreover, the results presented in our work should pave the way for further scientific investigation, to provide even better haptic mechanisms.

Haptic perception mechanism of softness – second report, relationship between stiffness of an object and softness sensation

A palpation is a useful method to detect cancer and to evaluate skin or under skin conditions. However, the palpation is a skillful method. Doctor's mental and physical conditions affect diagnoses by the palpation. Additionally, it is hard to share the feeling of palpation with other people because palpation is subjective skill. Therefore, the development of the sensor that can measure the skin and under skin condition of the body like softness as a doctor's palpation is demanded. In this paper, we focus on a haptic perception mechanism of human for evaluating the softness. Six objects are made to conduct sensory tests. The silicone rubber part of the objects has two kinds of thickness and three kinds of Young's modulus. Relationships between physical properties of evaluated objects and the softness that human feel in active touch are investigated. After that, to control the contact condition between objects and finger, a passive touch evaluation system is fabricated. Using the system, relationships between the stiffness of the objects and evaluated haptic softness are investigated under passive touch condition.

The ARICE Framework: Augmented Reality in Computing Education

Augmented Reality (AR) is a term for a live direct or an indirect view of a physical, real-world environment whose elements are augmented by computer-generated sensory input and output including sound, graphics or haptic input and feedback mechanisms. It has been reported that the use of AR for educational purposes provided opportunities for reflection, capabilities for multiple representations, and co-design of personalized learning experiences which contribute to promote active learning. However, most of the reported applications are for students at the elementary or high school level. There are no reported formal studies on AR application on a college/university level. Based on this lack of information, several questions arise: Are the benefits unique to the elementary and high school students? If AR is used in college classrooms, will it show similar benefits? This paper proposes an Augmented Reality in Computing Education (ARICE) framework for using an AR educational system in undergraduate computing education to improve student performance, retention and learning outcomes. A research plan on how to evaluate the framework has also been presented.

Decoupled and Coordinated Intelligent Force-position Control forMinimally Invasive Surgical Robot

In order to solve the problem that current commercially available minimally surgical robots do not include significant haptic(force) feedback mechanism,a novel decoupled and coordinated force-position control strategy with corresponding intelligent control system design is proposed based on bilateral decoupled and coordinated bio-regulation mechanism in human body,in which control features of minimally surgical robots are considered.Actual experiments are carried out with four 3-DOF(degree of freedom) haptic manipulators to illustrate the performance of the proposed intelligent controller system.The results indicate that the proposed control system can achieve decoupled and coordinated force-position control.The operator can get accurate force feedback to guarantee robot performing task harmoniously and stably.

Manipulability of a Haptic Mechanism within the Cylindrical Space of an MR Scanner

The aim of this paper is to present developed 3 DOF haptic mechanism and 3D visualization method for analysis of mechanism manipulability problems within limited space. Improvement in mechanism manipulability within cylindrical space is crucial for devices, which operate in MR tunnel. This solution enables the plotting of quantitative 3D representation for each point in the mechanism’s workspace, using selected resolution which can be determined in advance. The cross-section between the limited space and the whole arbitrary workspace shows the ability for movement execution.

Haptic perception mechanism of softness

A palpation is convenient and it is a useful method to detect a cancer and to evaluate softness of skin. However, the palpation is skillful method, and the mental/physical conditions of the experts affect the result of the palpation easily. The result of palpation is subjective and it is hard to share the result with the other people. Therefore, the development of the sensor that can measure the softness of the body is demanded. In this paper, a relationship between physical properties of measured objects and the softness that human feel are investigated for a development of a tactile sensor system. At first, the relationship between tactile softness and stiffness of the measured objects is investigated. As a result, tactile softness decreases with the increase of stiffness of the objects. Next, the relationship between tactile softness and size of contact area of human finger are investigated. These results lead to the conclusion that there is a possibility that tactile softness of the objects are not only related to the contact force or displacement of a finger and the objects but also to the contact area of the finger and the measured objects.

Audio-Tactile Feedback Mechanisms for Multi-Touch HMI Panels of Production Engineering Systems

Over the last decade, touch screen interaction has been gaining wide acceptance in information technology and daily consumer products. Accordingly, first approaches to applications and devices for production engineering systems are now entering the market. Although they employ intuitive user concepts, touch screens for industrial HMI panels still lack haptic feedback. Since operators observes the machining process and machine handling is often done blind, false handling or wrong input signalsmay damagemachines or injure human workers. With this in mind, this paper presents a haptic feedback mechanism for touch-based interaction. A user evaluation performed on the developed system unveils increasing input security and thus an enhanced user experience.

Design and analysis of an fMRI compatible haptic robot

Magnetic resonance (MR) compatible haptic devices have certain specific structural and operational properties, which are due to the magnetic field, and haptic requirements. Through the development of a haptic mechanism, which is compatible with a magnetic resonance environment, certain problems were solved, which are common to all robotic devices operating in an MR tunnel. This paper deals with the manipulability problem of a novel 3 DOF MR compatible haptic mechanism, considering limited space and its visualisation. An appropriate 3D visualisation method has been developed for analysing the manipulability characteristics of a haptic mechanism within an MR environment. Choosing a suitable driving system is one of the crucial design attributes for quality force transmission in haptic interfaces. This paper introduces certain adaptations, which have been done to enable the MR compatibility of a cable drive driven by an electric motor. It also presents the theoretical modelling of a cable drive for a 3 DOF MR compatible haptic mechanism, focusing on the hysteretic behaviour of polymeric cables.