The design of a novel parallel haptic device

A novel haptic device which is characterized by large workspace, high rigidity, simple kinematics and easy construction is presented. This device is a parallel mechanism which is composed of a base plate, three sub-chains, and a mobile plate. Each sub-chain is attached to the base plate through a pin joint and to the top plate through a spherical joint. The sub-chain is derived from and kinematically equivalent to a pantograph linkage but is redesigned to solve the difficult problem of motor-fitting. The spherical joint is of the ball-in-socket type, but has much larger workspace than its regular counterpart. The kinematics is analyzed, and the inverse kinematics analysis is performed with a geometric approach. The complete workspace is readily obtained with the spherical coordinate system searching method. The optimal value of the cone angle of the spherical joint is shown to be 100°.

Obstacle recognition using a haptic device

A haptic device is proposed which gives the user feedback information on their location and orientation of the obstacle through the mobile robot that detects the obstacle in an environment where the user cannot see.Mobile robot recognizes the exact position of the obstacle through configuring the nested ultrasonic sensor and giving feedback information to the haptic device.The haptic device consisting of five vibration motors can realize the haptic through the vibration of user's finger using the position information of the obstacle received feedback.In addition,it has high accuracy to recognize the surrounding environment and realizes the various situations with the fuzzy controller and the nested ultrasonic sensors.

Controller Design for a 3 D.O.F Haptic Interface Device

This paper presents a 3 D.O.F haptic interface which is designed to meet the interaction requirement of teleoperation tasks and virtual reality applications. The mechanism design takes the operability into consideration such as adopting steel cable as transmission component and mass balance to eliminate the gravity effect. The dynamics of haptic interface including actuating device is studied. In order to provide operator with fidelity kinesthetic information, a force controller using self-learning fuzzy logic control is designed. The simulation results verify the effectiveness of the control method.

Development of a Haptic Interface with Proximity Sensors and Vibration Motors

As described in this paper, we propose a new haptic interface for a service robot. For safety with service robots working in a space where people live, some notification before collision with an obstacle is desirable. To achieve such a function, we developed a master-slave manipulator system in which the slave manipulator surface is covered with many proximity sensors. Additionally, we developed a haptic device that feeds back proximity sense information to the operator using small vibration motors. We attached the haptic device to the arm of the operator and vibrated the vibration motor corresponding to the sensor. Thereby, the operator was able to ascertain the position of an object near the manipulator, and to make the robot maneuver to avoid it before collision. To confirm the system usefulness, we equipped subjects with the developed proximity sense presentation device and performed a detection-position-specific experiment and an obstacle avoidance experiment in a narrow space. As results of the detection position specific experiment on five subjects, four subjects reported the detection position correctly. The remaining one person failed because of his particular arm shape. Operation experiments conducted in a narrow space showed that all subjects＇ work was successful when given feedback of proximity sense information. Nobody was successful without proximity sense information. Results of these two experiments demonstrate that this proposed system is useful for obstacle avoidance of a master-slave manipulator system.

Robotic ultrasound:An initial feasibility study

BACKGROUND Performing ultrasound during the current pandemic time is quite challenging.To reduce the chances of cross-infection and keep healthcare workers safe,a robotic ultrasound system was developed,which can be controlled remotely.It will also pave way for broadening the reach of ultrasound in remote distant rural areas as well.AIM To assess the feasibility of a robotic system in performing abdominal ultrasound and compare it with the conventional ultrasound system.METHODS A total of 21 healthy volunteers were recruited.Ultrasound was performed in two settings,using the robotic arm and conventional hand-held procedure.Images acquired were analyzed by separate radiologists.RESULTS Our study showed that the robotic arm model was feasible,and the results varied based on the organ imaged.The liver images showed no significant difference.For other organs,the need for repeat imaging was higher in the robotic arm,which could be attributed to the radiologist’s learning curve and ability to control the haptic device.The doctor and volunteer surveys also showed significant comfort with acceptance of the technology and they expressed their desire to use it in the future.CONCLUSIONThis study shows that robotic ultrasound is feasible and is the need of the hour during thepandemic.

Robot Position Control Using Force Information for Cooperative Work in Remote Robot Systems with Force Feedback

This paper proposes robot position control using force information for cooperative work between two remote robot systems with force feedback in each of which a user operates a remote robot by using a haptic interface device while observing work of the robot with a video camera. We also investigate the effect of the proposed control by experiment. As cooperative work, we deal with work in which two robots carry an object together. The robot position control using force information finely adjusts the position of the robot arm to reduce the force applied to the object. Thus, the purpose of the control is to avoid large force so that the object is not broken. In our experiment, we make a comparison among the following three cases in order to clarify how to carry out the control effectively. In the first case, the two robots are operated manually by a user with his/her both hands. In the second case, one robot is operated manually by a user, and the other robot is moved automatically under the proposed control. In the last case, the object is carried directly by a human instead of the robot which is operated by the user in the second case. As a result, experimental results demonstrate that the control can help each system operated manually by the user to carry the object smoothly.

Elevating haptic interfaces:Dual-rate sampling and field programmable gate array implementation for multi-degree-of-freedom performance enhancement

In this work,our primary focus centered on exploring the adaptability of the dualrate sampling scheme proposed earlier to enhance the performance of multi-degreeof-freedom(multi-DOF)impedance-based haptic interfaces.The scheme employed independent sampling rates in a haptics controller,effectively mitigating the issue of reduced Z-width at higher sampling rates.A key aspect of our investigation was the intricate implementation of the dual-rate sampling scheme on a field programmable gate array(FPGA).This implementation on a logic hardware FPGA was challenging and led to the effective comparison of the uniform-rate and dual-rate sampling schemes of the multi-DOF haptic controller.We used an in-house developed two-DOF pantograph as the haptic interface and an FPGA for implementing the controller strategy.FPGA-based implementation presented challenges that were vital in testing controller performances at higher sampling rates.Virtual wall experiments were conducted to determine the stable and unstable interactions with the virtual wall.To complement the experimental results,we simulated the haptics force law for multi-DOF system on Simulink/MATLAB.Notably,the dual-rate sampling approach maintained the Z-width of the two-DOF haptic interface,even at higher controller sampling rates,distinguishing it from the conventional two-DOF uniform-rate control scheme.For example,employing a dual-rate sampling combination of 20–2 kHz consistently ensured the stable rendering of a maximum virtual stiffness of approximately 700 N/mm and maintained a reliable virtual damping range spanning from 0 to 5 Ns/mm.In contrast,the 20 kHz uniform-rate sampling approach failed to ensure interface stability in the presence of virtual damping,ultimately resulting in the unsuccessful implementation of any virtual stiffness at higher sampling rates.This work,therefore,establishes the potential of dual-rate sampling in the realm of haptic technology,with practical applications in multi-DOF systems.