Virtual Force Feedback Lessons, Challenges, Future Applications

1993 ◽  
Vol 5 (2) ◽  
pp. 178-182 ◽  
Author(s):  
Grigore C. Burdea ◽  
◽  
Noshir A. Langrana ◽  

Virtual force feedback prototypes have been developed in the last couple of years. Their number of degrees of freedom and range of motion are limited by present (bulky) actuator technology. Lessons from these first prototypes point to possible solutions in the future. Several applications of virtual reality with force feedback are then described.

Author(s):  
Manuel Rodrigues Quintas ◽  
Maria Teresa Restivo ◽  
José Rodrigues ◽  
Pedro Ubaldo

The concept and the use of haptic devices need to be disseminated and they should become familiar among young people. At present haptics are used in many everyday tasks in different fields. Additionally, their use in interaction with virtual reality applications simulating real systems sense of touch will increase the usersâ?? realism and immersion and, consequently, they will contribute to improve the intrinsic knowledge to the simulationsâ?? goals. However, haptics are associated with expensive equipment and usually they offer several degrees of freedom. The objective of this work is to make their cost not much more expensive than a â??specialâ? mouse by offering a low cost solution with just one degree of freedom (1DOF) useful in many simple cases. Additionally, it is also an objective of this work the development of simple virtual reality systems requiring interactions only requiring one degree of freedom. A low cost, single-axis force-feedback haptic device of 1 degree of freedom has been developed. For evaluating the interest of this prototype a â??Spring Constantâ? application was built and used as a demonstrator. The complete system - the haptic interacting with the â??Spring Constantâ? - will be described in the present work.


2021 ◽  
Author(s):  
C. Genova ◽  
E. Biffi ◽  
S. Arlati ◽  
D. F. Redaelli ◽  
A. Prini ◽  
...  

AbstractA large number of people in the world need to use a wheelchair because of different disabilities. Driving a wheelchair requires complex physical and cognitive abilities which need to be trained. Virtual training helps users acquire driving skills in a safe environment. The aim of this paper is to describe and technically validate simulation models for both manual (MW) and powered wheelchairs (PW) based on immersive virtual reality CAVE (VR). As VR system, the Gait Real-time Analysis Interactive Lab (GRAIL) was used, a CAVE equipped with a motion platform with two degrees of freedom and an optoelectronic motion capture system. A real wheelchair was positioned onto the motion platform with rear wheels free to turn in MW modality, and a commercial joystick was installed on an armrest to simulate the PW modality. Passive markers were used to track the wheel rotation, the joystick and the user hand motion. Custom D-flow applications were developed to manage virtual scene response to user actions. Overground tests, based on single wheel rotation, were performed to verify the simulation model reliability. Quantitative results demonstrated that the MW simulator kinematics was consistent with a real wheelchair overground in the absence of wheel slip and inertia (median error for MW 0.40 °, no systematic bias p = 0.943, high correlation rho > 0.999, p < 0.01). The proposed solution is flexible and adaptable to different wheelchairs, joysticks and optoelectronic systems. The main limitation is the absence of force feedback. Nevertheless, it is a reliable prototype that can be used to validate new virtual scenarios as well as for wheelchair training. The next steps include the system validation with real end users and assessment of the simulator effectiveness as a training tool.


2009 ◽  
Vol 6 (2) ◽  
pp. 115-126 ◽  
Author(s):  
Antonio Frisoli ◽  
Fabio Salsedo ◽  
Massimo Bergamasco ◽  
Bruno Rossi ◽  
Maria C. Carboncini

This paper presents the design and the clinical validation of an upper-limb force-feedback exoskeleton, the L-EXOS, for robotic-assisted rehabilitation in virtual reality (VR). The L-EXOS is a five degrees of freedom exoskeleton with a wearable structure and anthropomorphic workspace that can cover the full range of motion of human arm. A specific VR application focused on the reaching task was developed and evaluated on a group of eight post-stroke patients, to assess the efficacy of the system for the rehabilitation of upper limb. The evaluation showed a significant reduction of the performance error in the reaching task (pairedt-test, p < 0.02)


Author(s):  
Carlo Ferraresi ◽  
Massimiliana Carello ◽  
Francesco Pescarmona ◽  
Roberto Grassi

The paper presents the results of a work carried out by the Department of Mechanics of Politecnico di Torino, concerning the study and development of a six degrees of freedom force reflecting master structure for teleoperation (haptic device) to be controlled by an operator. The latter imposes the six-dimensional linear and angular displacement of a handle, controlling a remote slave robot or interacting with virtual reality. On the other hand, the operator receives a force feedback related to the environment in which the slave robot or virtual device operates. Since the actuators must be force controlled in order to generate a resultant corresponding to the desired wrench, pneumatic actuation has been chosen because it is particularly suitable to the application and quite economical.


2012 ◽  
Vol 24 (6) ◽  
pp. 958-966 ◽  
Author(s):  
Lingtao Huang ◽  
◽  
Takuya Kawamura ◽  
Hironao Yamada ◽  

We developed a master-slave operation system for a teleoperation construction robot that recognizes the hardness of a grasped object. To manipulate an object, the system uses an excavator with four degrees of freedom as a slave and two joysticks with force feedback equipment as a master. Based on creating a friendly user interface, the operation system uses multimodel sensory force and visual feedback to successfully discriminate among soft object types during operation. The construction robot measures the hardness of an object using the pressure of a piston obtained by pressure sensors on the cylinder and the closed or open state of a fork glove in the process of grasping an object. By incorporating an object-hardness calculation method with master-slave control of the system, an operator then can feel the sense of reaction force to joysticks and distinguish the hardness of an object while controlling the construction robot. In addition, parameters on object-hardness calculation are presented to the operator to improve the system’s controllability. Color prompting is provided in virtual space to enable the operator to identify the hardness of an object. To evaluate the system, object-type recognition tests were conducted, including the grasping and conveying of blocks of concrete, tires, urethane foam and sponge foam. According to statistical analysis of experimental results, we confirmed that the operation system contributes to achieving the successful discrimination of object hardness during teleoperation work.


Author(s):  
Roxana Steliana Miclaus ◽  
Nadinne Roman ◽  
Ramona Henter ◽  
Silviu Caloian

More innovative technologies are used worldwide in patient’s rehabilitation after stroke, as it represents a significant cause of disability. The majority of the studies use a single type of therapy in therapeutic protocols. We aimed to identify if the association of virtual reality (VR) therapy and mirror therapy (MT) exercises have better outcomes in lower extremity rehabilitation in post-stroke patients compared to standard physiotherapy. Fifty-nine inpatients from 76 initially identified were included in the research. One experimental group (n = 31) received VR therapy and MT, while the control group (n = 28) received standard physiotherapy. Each group performed seventy minutes of therapy per day for ten days. Statistical analysis was performed with nonparametric tests. Wilcoxon Signed-Rank test showed that both groups registered significant differences between pre-and post-therapy clinical status for the range of motion and muscle strength (p < 0.001 and Cohen’s d between 0.324 and 0.645). Motor Fugl Meyer Lower Extremity Assessment also suggested significant differences pre-and post-therapy for both groups (p < 0.05 and Cohen’s d 0.254 for the control group and 0.685 for the experimental group). Mann-Whitney results suggested that VR and MT as a therapeutic intervention have better outcomes than standard physiotherapy in range of motion (p < 0.05, Cohen’s d 0.693), muscle strength (p < 0.05, Cohen’s d 0.924), lower extremity functionality (p < 0.05, Cohen’s d 0.984) and postural balance (p < 0.05, Cohen’s d 0.936). Our research suggests that VR therapy associated with MT may successfully substitute classic physiotherapy in lower extremity rehabilitation after stroke.


Author(s):  
Xiaoli Zhang ◽  
Carl A. Nelson

The size and limited dexterity of current surgical robotic systems are factors which limit their usefulness. To improve the level of assimilation of surgical robots in minimally invasive surgery (MIS), a compact, lightweight surgical robotic positioning mechanism with four degrees of freedom (DOF) (three rotational DOF and one translation DOF) is proposed in this paper. This spatial mechanism based on a bevel-gear wrist is remotely driven with three rotation axes intersecting at a remote rotation center (the MIS entry port). Forward and inverse kinematics are derived, and these are used for optimizing the mechanism structure given workspace requirements. By evaluating different spherical geared configurations with various link angles and pitch angles, an optimal design is achieved which performs surgical tool positioning throughout the desired kinematic workspace while occupying a small space bounded by a hemisphere of radius 13.7 cm. This optimized workspace conservatively accounts for collision avoidance between patient and robot or internally between the robot links. This resultant mechanism is highly compact and yet has the dexterity to cover the extended workspace typically required in telesurgery. It can also be used for tool tracking and skills assessment. Due to the linear nature of the gearing relationships, it may also be well suited for implementing force feedback for telesurgery.


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