Bond Graph Based Approach to Passive Teleoperation of a Hydraulic Backhoe

2005 ◽  
Vol 128 (1) ◽  
pp. 176-185 ◽  
Author(s):  
Kailash Krishnaswamy ◽  
Perry Y. Li

Human operated, hydraulic actuated machines are widely used in many high-power applications. Improving productivity, safety and task quality (e.g., haptic feedback in a teleoperated scenario) has been the focus of past research. For robotic systems that interact with the physical environments, passivity is a useful property for ensuring safety and interaction stability. While passivity is a well utilized concept in electromechanical robotic systems, investigation of electrohydraulic control systems that enforce this passivity property are rare. This paper proposes and experimentally demonstrates a teleoperation control algorithm that renders a hydraulic backhoe/force feedback joystick system as a two-port, coordinated, passive machine. By fully accounting for the fluid compressibility, inertia dynamics and nonlinearity, coordination performance is much improved over a previous scheme in which the coordination control approximates the hydraulic system by its kinematic behavior. This is accomplished by a novel bond graph based three step design methodology: (1) energetically invariant transformation of the system into a pair of “shape” and “locked” subsystems; (2) inversion of the shape system bond graph to derive the coordination control law; (3) use of the locked system bond graph to derive an appropriate control law to achieve a target locked system dynamics while ensuring the passivity property of the coordinated system. The proposed passive control law has been experimentally verified for its bilateral energy transfer ability and performance enhancements.

Author(s):  
Kailash Krishnaswamy ◽  
Perry Y. Li

Human operated, hydraulic actuated machines are widely used in many high-power applications. Improving productivity, safety and task quality (eg. force feedback to the operator in a teleoperated scenario) has been the focus of past research. In addressing these issues, our research proposes and experimentally demonstrates a control technique that renders a hydraulic machine (teleoperated backhoe in this case) as a two-port, co-ordinated, passive machine. The passive teleoperated backhoe is driven by a human operator at one-port and interacts with the environment at the other. It guarantees interaction stability and safety with the human / work environment as the latter are usually passive. In previous work, a passive teleoperation algorithm was proposed for multi degree of freedom teleoperation of a hydraulic backhoe approximated by its kinematic behavior. The approximation led to severe performance deterioration under certain operating conditions. In this paper, a bondgraph based passive teleoperation architecture is proposed for the non-linear dynamic modeled backhoe. Passive control is designed in two stages. In the first stage, bondgraph based system inversion ideas are used to determine a coordination control law. In the second stage, a desired locked system (desired dynamics of the coordinated teleoperator) is defined and an appropriate control law is determined to ensure the passivity property of the locked teleoperator. The proposed passive control law is experimentally verified for its bilateral energy transfer ability and performance enhancements.


Author(s):  
Erfan Pakdamanian ◽  
Lu Feng ◽  
Inki Kim

It remains uncertain regarding the safety of driving in autonomous vehicles that, after a long, passive control and inattention to the driving situation, how the drivers will be effectively informed to take-over the control in emergency. In particular, the active role of vehicle force feedback on the driver’s risk perception on curves has not been fully explored. To investigate it, the current paper examined the driver’s cognitive and visual responses to the whole-body haptic feedback during curve negotiations. The effects of force feedback on drivers’ responses on curves were investigated in a high-fidelity driving simulator while measuring EEG and visual gaze over ten participants. The preliminary analyses of the first two participants revealed that pupil diameter and fixation time on the curves were significantly longer when the driver received whole-body feedback, compared to none. The findings suggest that whole-body feedback can be used as an effective “advance notification” of hazards.


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.


2005 ◽  
Vol 2005 ◽  
pp. 247-253 ◽  
Author(s):  
S. Jarvis ◽  
J.E.L. Day ◽  
B. Reed

Animal science research is important in relation to our understanding of animals, their function and performance, and their relationships with their social and physical environments. Animal science research covers a wide range of disciplines and so can lead to the use of a variety of experimental techniques on animals for many different purposes. This has the potential to lead to a multitude of diverse ethical issues. Members of the British Society of Animal Science and authors of papers submitted to the Society for publication come from countries around the world and therefore are subject to differences in legislative requirements and recommendations regarding animal experimentation. These legal requirements, along with the ethical implications of the research must be fully considered before any experimental work is undertaken.


2016 ◽  
Vol 10 (4) ◽  
pp. 288-304 ◽  
Author(s):  
Syagnik Banerjee ◽  
Phil Longstreet

Purpose With the ubiquitous diffusion of mobile-enabled internet, individuals are constantly immersed in both virtual and physical environments. While this causes distractions, lower attention spans and disasters such as texting while driving and walking, it also creates synergies and smoother navigational experiences. Technology developers, marketers and policy-makers are both concerned and intrigued to understand how to deploy these mobile technologies so as to optimize their disruptive impact. In this paper, the authors aim to develop a framework of dual consciousness to understand the potential causes and outcomes of individual’s simultaneous presence in physical and virtual worlds. Design/methodology/approach A careful review of past academic literature on behavior, as well as media reports of incidents of disruptions, led the authors to construct a 2 × 2 framework depicting behaviors that indicated high-low consciousness in physical, as well as virtual worlds. Findings In dual environments, individuals either dissociate from one of the environments or integrate both environments. While the former is driven by the multiplicity of irrelevant roles and goals, oblivion of relevant roles, perception of group norms and performance of practiced routine tasks, the latter is driven by strong executive control processes, focused singular goals and usage of the virtual environment to reinforce their physical tasks. The most affected parties are retailers, service providers, digital marketers and social media marketers. Originality/value Most prior research in interactive marketing examine effects of online stimuli on online behavior. This paper identifies the noise created by physical context on clicks as well as the interference created by virtual stimuli on physical purchases and service experiences.


2015 ◽  
Vol 19 (06) ◽  
pp. 1540009 ◽  
Author(s):  
SARAH MAHDJOUR

What do growth-oriented business models look like? While several economic theories, such as the theory of the firm, are based on the assumption that firms aim to maximise their profits, past research has shown that growth intention is heterogeneous among firms and that many business owners prefer to keep their firm at a size that they can manage with few resources. This paper explores the relationship of growth intention and business models, based on a sample of 135 German ICT businesses. Following an exploratory approach, Mann–Whitney U tests are applied to analyse how different business model designs correspond with different levels of growth intention. The results indicate that growth intention relates to business owners’ decisions regarding the provision of consulting services, the level of standardisation in offered products and services, the choice of addressed markets, the implementation of competitive strategies based on cost efficiency and of revenue streams based on one-time- and performance-based payments. Furthermore, the results show that growth oriented firms are no more likely than non-growth oriented firms to adapt their business models dynamically to changed internal or external conditions.


2000 ◽  
Author(s):  
Michael L. Turner ◽  
Ryan P. Findley ◽  
Weston B. Griffin ◽  
Mark R. Cutkosky ◽  
Daniel H. Gomez

Abstract This paper describes the development of a system for dexterous telemanipulation and presents the results of tests involving simple manipulation tasks. The user wears an instrumented glove augmented with an arm-grounded haptic feedback apparatus. A linkage attached to the user’s wrist measures gross motions of the arm. The movements of the user are transferred to a two fingered dexterous robot hand mounted on the end of a 4-DOF industrial robot arm. Forces measured at the robot fingers can be transmitted back to the user via the haptic feedback apparatus. The results obtained in block-stacking and object-rolling experiments indicate that the addition of force feedback to the user did not improve the speed of task execution. In fact, in some cases the presence of incomplete force information is detrimental to performance speed compared to no force information. There are indications that the presence of force feedback did aid in task learning.


2018 ◽  
Vol 35 (2) ◽  
pp. 149-160 ◽  
Author(s):  
Mustufa H. Abidi ◽  
Abdulrahman M. Al-Ahmari ◽  
Ali Ahmad ◽  
Saber Darmoul ◽  
Wadea Ameen

AbstractThe design and verification of assembly operations is essential for planning product production operations. Recently, virtual prototyping has witnessed tremendous progress, and has reached a stage where current environments enable rich and multi-modal interaction between designers and models through stereoscopic visuals, surround sound, and haptic feedback. The benefits of building and using Virtual Reality (VR) models in assembly process verification are discussed in this paper. In this paper, we present the virtual assembly (VA) of an aircraft turbine engine. The assembly parts and sequences are explained using a virtual reality design system. The system enables stereoscopic visuals, surround sounds, and ample and intuitive interaction with developed models. A special software architecture is suggested to describe the assembly parts and assembly sequence in VR. A collision detection mechanism is employed that provides visual feedback to check the interference between components. The system is tested for virtual prototype and assembly sequencing of a turbine engine. We show that the developed system is comprehensive in terms of VR feedback mechanisms, which include visual, auditory, tactile, as well as force feedback. The system is shown to be effective and efficient for validating the design of assembly, part design, and operations planning.


2005 ◽  
Vol 128 (2) ◽  
pp. 216-226 ◽  
Author(s):  
M. A. Vitrani ◽  
J. Nikitczuk ◽  
G. Morel ◽  
C. Mavroidis ◽  
B. Weinberg

Force-feedback mechanisms have been designed to simplify and enhance the human-vehicle interface. The increase in secondary controls within vehicle cockpits has created a desire for a simpler, more efficient human-vehicle interface. By consolidating various controls into a single, haptic feedback control device, information can be transmitted to the operator, without requiring the driver’s visual attention. In this paper, the experimental closed loop torque control of electro-rheological fluids (ERF) based resistive actuators for haptic applications is performed. ERFs are liquids that respond mechanically to electric fields by changing their properties, such as viscosity and shear stress electroactively. Using the electrically controlled rheological properties of ERFs, we developed resistive-actuators for haptic devices that can resist human operator forces in a controlled and tunable fashion. In this study, the ERF resistive-actuator analytical model is derived and experimentally verified and accurate closed loop torque control is experimentally achieved using a non-linear proportional integral controller with a feedforward loop.


Author(s):  
J. E. N. Jaspers ◽  
M. Shehata ◽  
F. Wijkhuizen ◽  
J. L. Herder ◽  
C. A. Grimbergen

Performing complex tasks in Minimally Invasive Surgery (MIS) is demanding due to a disturbed hand-eye co-ordination, the use of non-ergonomic instruments with limited degrees of freedom (DOFs) and a lack of force feedback. Robotic telemanipulatory systems enhance surgical dexterity by providing up to 7 DOFs. They allow the surgeon to operate in an ergonomically favorable position with more intuitive manipulation of the instruments. Commercially available robotic systems, however, are very bulky, expensive and do not provide any force feedback. The aim of our study was to develop a simple mechanical manipulator for MIS. When manipulating the handle of the device, the surgeon’s wrist and grasping movements are directly transmitted to the deflectable instrument tip in 7 DOFs. The manipulator consists of a parallelogram mechanism with steel wires. First phantom experience indicated that the system functions properly. The MIM provides some force feedback improving safety. A set of MIMs seems to be an economical and compact alternative for robotic systems.


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