Deformation-Based Tactile Feedback Using a Biologically-Inspired Sensor and a Modified Display

This study examined the impact of adding vibrotactile feedback to existing force feedback in a VR-Haptic needle insertion simulation. A new programmable tactile feedback system using direct digital synthesis (DDS) to drive LRA and piezo actuators was designed and integrated into the VR needle simulation. A user study measured needle insertion performance, usability, and user preferences for realistic vein insertion. Results showed that vibrotactile feedback (via piezo and LRA) combined with force feedback improved needle insertion performance over LRA and realism over Force Feedback alone. Participants preferred the combination of force and vibrotactile feedback. While vibrotactile feedback cannot replace force feedback, it serves as a valuable supplemental cue, enhancing overall realism. This suggests that dual-modal haptic feedback, combining force (kinesthetic) and tactile (cutaneous) cues, can address the limitations of single-modal force feedback.

When we use a tool to explore or manipulate an object, friction between the surface of the tool and the fingerpads generates skin stretch cues that are related to the interaction forces between the tool and the object. In this study, we emulate these naturally occurring skin stretch cues in order to convey force direction and magnitude information to users during teleoperation. We hypothesize that skin stretch feedback is a useful substitute for kinesthetic force feedback in force-sensitive teleoperated tasks. In this study, ten participants performed teleoperated palpation to determine the orientation of a stiff region in a surrounding artificial tissue using five feedback conditions: skin stretch, force, reduced gain force, graphic, and vibration. When participants received skin stretch feedback, they localized the stiff region as well as with force feedback, with no increase in task completion time. Additionally, participants receiving skin-stretch feedback localized the stiff region statistically significantly more accurately than those using vibration feedback. Although participants using skin stretch exhibited higher interaction forces than when using force, vibration, and graphical feedback, skin stretch statistically significantly decreased interaction forces compared with reduced gain force feedback. Thus, skin-stretch feedback is a compelling substitute for force feedback and may be useful in scenarios where force feedback is reduced or infeasible.

Review on aspects of artificial tactile feedback in laparoscopic surgery

Tactile displays have been proposed as a human-computer interface. Nowadays, it is utilised in hundreds of applications and a standard means of information presentation. Shape information display became essential to many surgical tasks (finding hidden anatomical features and locating tumours). There is a strong need for shape tactile display devices particularly for specialists who ought to feel the tissue shape and hardness amid laparoscopic surgeries. This paper describes the design and implementation of adaptive position controller for a tactile shape display device. The proposed display comprises of an cluster of 3×3 upward/downward free mobile pins based on SMA actuators. Each actuator is competent of creating a 5 mm uprooting as greatest. Due to the complex hysteresis and non-linear response of SMA actuators, a fuzzy logic auto-tuner algorithm is constructed to create the PI controller gains adaptive. The suggested controller is implemented to control the shape display tactile system. The proposed controller present prevalent response over existing controllers in the survey from point of no steady state error, no overshoot, no chattering and minimized hysteresis.

In haptic interaction, friction caused by slip on the fingertip is a key factor for manual manipulation as well as exploration of texture and shape. From the moment of contact, the friction contains vertical and tangential skin deformations and vibrations, not all of which have been simultaneously supported by previous portable/wearable haptic devices. We propose a portable haptic device that has the ability to present skin deformation and vibration with two degrees of freedom by using two types of motors: a voice coil motor (VCM) for vertical motion and vibration, and direct current motors for tangential skin stretch. The VCM also achieves encounter-type haptic interactions. A combination of these motions encompasses most cutaneous cues for realistic friction.

This paper presents a small and lightweight tactile display system and describes its capabilities with respect to spatial and temporal tactile feedback. Each tactile display module is comprised of a 4times4 piezoelectric ultrasonic actuator array with a spatial resolution of 1.5 mm and a temporal resolution of 20 Hz. The objective of this research is to build a small and lightweight tactile display system such that the system, including the display modules and complete controller parts, will be wearable by a user. It was found that the developed tactile display module can display both spatial and temporal information with less power consumption.

A basic device combining a tactile graphic display function and a touch position sensing function is proposed. The trial device consists of two major components, a tactile graphic display and a force sensor. The force sensor measures a center of gravity generated by touch action on the display surface and a PC estimates the point based on the data. The fundamental function for achieving the interactive communication is to detect the location where user is touching a tangible surface. By applying this functions, the click and scroll function by an empty hand are realized. In addition, an audio-tactile graphic system which can be used mainly to overcome tactile cognitive limitation is implemented as an application of the system. Moreover, the area of tactile display is expanded for the purpose of improvement userability. Following this, we propose the tactile scrollbar where the users can recognize their position of plane space. The validity of the developed tactile graphic system has been confirmed through subjective experiments.

Encoding and presentation of surface textures using a mechanotactile display

During interaction with remote environments, the operator may benefit from the addition of force feedback to the ubiquitous visual feedback. However, the apparatus required for reactive force feedback (feedback which imposes the remote environment's motion-constraints on the user by applying joint torques) is cumbersome and expensive, especially when implemented in conjunction with high degree-offreedom precision joint motion sensing. Non-reactive, tactile feedback can provide similar information, and can be implemented at much lower cost. The purposes of this research were (1)todesign and demonstrate an inexpensive tactile feedback system, and (2) to determine the extent to which such a system could aid in the performance of a simple teleoperation task. After some experimentation with some different display technologies, and preliminary design, a vibrotactile display was chosen because of its low weight, size, and low cost. The final design consisted of two voice-coils, one each for the thumb and the index finger, which were driven by a 250 Hz variableamplitude signal produced by an analog electronics unit which was controlled by a PC. Experimental results are provided to show that the addition of the tactile display provides a small but significant improvement in manual tracking performance over the use of the visual display alone, and that the tracking task may be performed with only the tactile display. In further experiments the tactile display is compared with reactive force-feedback and is shown to confer most of the reactive display's performance improvement over tracking with only a visual display.

This paper presents the work conducted towards the realization of a novel tactile display system composed of miniature thermo-fluidic actuators. An application of the system particularly relevant to blind individuals is communication with computers through touch. The development of programmable spatio-temporal pattern of touch actuation based on bubble formation and vapor pressure has remarkable scope, not only because of the flexibility and wearability but also the high levels of motion amplitude and force of actuation not achieved so far by other means. The design specifications of the tactile display involved packaging of the miniature actuators in such a manner that the display can be conveniently attached at the tip of the human finger with desirable spatial resolution, and achieving the optimum force that can be felt through the human finger. However, there were challenges that were faced by the authors while miniaturizing the actuators for suitability in sub-millimeter spatial resolution desirable for the tactile display. The paper reports on the design, prototype development and experimental results and brings out the limitations along with possible solutions being pursued by the authors. The progressive efforts through fabrication and testing of different prototype thermo-fluidic actuators ranging from 3mm diameter bore to sub-millimeter sizes and the corresponding difficulties faced in the form of cooling requirements, hysteresis effects, and fabrication challenges are elucidated. The paper reports on packaging of actuators as an array of tiny tubes spaced as close as possible, and establishment of parameters, namely, amplitude of actuation and switching frequency, along with force generation adequate for tactile perception.

Tactile displays are haptic devices capable of rendering shape and texture information. Unsolved challenges in building tactile shape displays include their traditionally large form factors, low spatial resolution, and high costs. Using electrostatic adhesion to individually brake each pin and a single platform for global actuation, we developed a prototype static refreshable tactile shape display with high spatial resolution (1.7 mm pitch, 0.8 mm pin width; 4 mm pitch, 1.6 mm pin width), high resistance force (76.3 gf static-loading force per pin for 1.6 mm width) and low cost ($0.11 USD per pin for raw material). We present an analytical model of our electroadhesive brake mechanism and evaluate its maximum contact force and robustness in various conditions. To demonstrate the mechanism's potential, we built a static tactile shape display prototype with a 4×2 array of pins controlled using electroadhesive brakes. To further increase maximsum contact force allowed by our device, we develop and evaluate a global mechanical clutch which can be engaged during user interaction. A user study is carried out to compare our static tactile shape display's performance with printed 2.5D tactile graphics in a shape recognition task, and comparable shape recognition rates and response times are observed.

In view of the lack of effective feedback function for the minimally invasive surgical robot at present, the design of force feedback device and verification of force feedback effect of the master manipulator are carried out, so that the operator of the master manipulator can obtain force feedback and improve the quality of surgery. A force feedback method based on the variable1shear stress characteristics of magnetorheological fluid is proposed. The telecentric mechanism of the main manipulator end and the force feedback device are designed. And the relationship model of the output torque of the force feedback device, magnetic field intensity and angular velocity is established. The output characteristics of the device is analyzed by the experiment, and the linear relationship model between input current and output force of the force feedback device is obtained. The working performance of the force feedback device is tested by simulating the force conditions of surgical instruments in different cases of prostatectomy. The experimental results show that the delay of the force feedback device is 0.1-0.2 s, and the output performance of the force feedback device is related to the type and value of the applied force signal. When the input force signals are step signal, pulse signal and small range fluctuation signal, the average error of force feedback decreases with the increase of applied force. Analyzed from the experimental results, the overall force feedback effect of the force feedback device is well, which proves its feasibility and effectiveness in assisting doctors to carry out minimally invasive surgery.

In this paper, we propose cell-based pin-array tactile display which uses cell-based pins that express 2D-shape of character (letter, digit, etc.) in the form of line unlike general pins that offer stimulation of spot form. Human operator recognizes the information of letter or digit by scanning tactile display device's surface freely using skin tissue of user's fingertip. We examined the possibility of practical usage as small tactile display for mobile and wearable environment through implementation of device's simple model and user's test.

This paper presents the development of a compact tactile display and its integration in teleoperation. The system's operation is based on the display of surface shape to an area of the fingertip through a 4 × 4 array of tactors moving perpendicularly to the skin surface. The tactors are spring loaded and are actuated remotely by dc motors through a flexible tendon transmission. This novel implementation of conventional actuation principles achieves a compact design with superior performance compared to devices of a similar footprint, demonstrating an excellent combination of tactor spatiotemporal resolution, force, and amplitude. The display's ergonomic design and high performance make it suitable for integration on haptic devices for tactile feedback in VR and in Teleoperation. This paper presents the design, control, and performance of the tactile display and of the transmission system. It also demonstrates its integration on an Omega7 force feedback device for the teleoperation of an LWR KUKA manipulator. An experiment is presented where users teleoperated the stylus of the robot in a 3D contour following task with and without tactile feedback. In this experiment, force feedback from the slave is fused with model-based local tactile feedback. Subjects' performances indicate an improvement in teleoperation when both tactile and force feedback are present.

A new controller design method for bilateral force-reflecting teleoperators orientated to telesurgical applications is presented. The impedance of the remote environment is estimated online and the parameters of the system controller are adaptively updated accordingly. The proposed method shows quite visible improvement of haptic (force) feedback fidelity under the condition of stability compared to traditional passivity-based approaches.