Enhancement of Stability and Transparency in Teleoperated Robots Through Isotropy-Based Design
TL;DR: It is proposed in this paper that an isotropy based design of robots is necessary for recovering the additional stable and transparent behavior of the system, apart from what a controller can achieve.
Abstract: The primary challenge in implementing teleoperated master-slave robots is that both of its objectives - stability and transparency, are conflicting to each other. This trade-off is usually attributed to the time-delay in the communication channel, and state-of-the-art controllers are proposed primarily to counteract the effects of this time delay. Despite such controllers, it is observed that the system suffers from instability and inaccurate force feedback (loss of transparency), at least under certain conditions. This is because issues other than time delay which cause oscillations and inaccurate force feedback are rarely addressed in the literature. In this paper, such issues are clearly identified and it is shown here that controller design cannot counteract these issues. It is proposed in this paper that an isotropy based design of robots is necessary for recovering the additional stable and transparent behavior of the system, apart from what a controller can achieve. Another significant contribution of this paper is that because of the proposed design, the need for two signals from the traditional four-channel teleoperation architecture is eliminated, thus reducing the complexity of the system. Experimental validation is carried out by implementing a two-channel architecture on the designed robots.
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TL;DR: The accurate sensing and display of the delicate needle‐tissue interaction force to the operator is desirable for needle insertion procedures and has a great significance in improving surgical safety and reducing the incidence of complications.
Abstract: The accurate sensing and display of the delicate needle‐tissue interaction force to the operator is desirable for needle insertion procedures. It not only plays a significant role in the surgical treatment effect, but also has a great significance in improving surgical safety and reducing the incidence of complications. However, the direct detection of the interaction force between the tissue and needle tip by placement of a force sensor is challenging owing to the constraints of miniaturisation, cost, and sterilisation.
4 citations
TL;DR: In this article, a goniometer-type specimen stage with a linear actuation mechanism mounted on a rotation mechanism is introduced, where the linear actuators are arranged perpendicular to each other.
Abstract: In this paper, a goniometer-type specimen stage with a linear actuation mechanism mounted on a rotation mechanism is introduced. The linear actuation mechanism was modeled as a spatial parallel manipulator consisting of a moving body, three linear actuators, and an anti-rotation mechanism. The three linear actuators were arranged perpendicular to each other. In the specimen stage, the linear actuators were in ball contact with the surface of a holder designed to hold a specimen. For the parallel manipulator, the ball contact was replaced with two prismatic joints and a spherical joint. The mobility of the manipulator without the anti-rotation mechanism was one degree of freedom greater than the number of actuators. Therefore, the redundant one degree-of-freedom motion was restrained using an anti-rotation mechanism with three rotation joints and two prismatic joints. The inverse and direct kinematics of the goniometer mechanism were derived and verified. In addition, the inverse Jacobian was derived, and local and global performance indices were analyzed by the terms of manipulability and isotropy. Finally, the goniometer-type specimen stage was designed by the global performance indices.
References
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Book•
01 Jan 1986
TL;DR: This chapter discusses Jacobians: Velocities and Static Forces, Robot Programming Languages and Systems, and Manipulator Dynamics, which focuses on the role of Jacobians in the control of Manipulators.
Abstract: 1. Introduction. 2. Spatial Descriptions and Transformations. 3. Manipulator Kinematics. 4. Inverse Manipulator Kinematics. 5. Jacobians: Velocities and Static Forces. 6. Manipulator Dynamics. 7. Trajectory Generation. 8. Manipulator Mechanism Design. 9. Linear Control of Manipulators. 10. Nonlinear Control of Manipulators. 11. Force Control of Manipulators. 12. Robot Programming Languages and Systems. 13. Off-Line Programming Systems.
5,992 citations
01 Oct 1993
TL;DR: It is shown that a proper use of an four channels is of critical importance in achieving high performance telepresence in the sense of accurate transmission of task impedances to the operator.
Abstract: Tools for quantifying teleoperation system performance and stability when communication delays are present are provided A general multivariable system architecture is utilized which includes all four-types of data transmission between master and slave: force and velocity in both directions It is shown that a proper use of an four channels is of critical importance in achieving high performance telepresence in the sense of accurate transmission of task impedances to the operator It is also shown that transparency and robust stability (passivity) are conflicting design goals in teleoperation systems The analysis is illustrated by comparing transparency and stability in two common architectures, as well as a recent passivated approach and a new transparency-optimized architecture, using simplified one-degree-of-freedom examples >
2,083 citations
"Enhancement of Stability and Transp..." refers background in this paper
...It is claimed almost 3 decades ago in [20] that a 4-channel architecture is mandatory for simultaneous achievement of both stability and transparency of the teleoperation system....
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...In fact, this is the prime reason for incorporating the traditional 4-channel architecture [20]....
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...As mentioned in [20], transparency requires accurate force tracking along with position tracking....
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...Further, the force tracking error also converging to zero (with a negligible error in the order of 1mN-m), along with accurate position tracking, demonstrates the transparency of the system [20]....
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...This is true even in the case of one of the first and break through four-channel architectures mentioned in [20]....
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TL;DR: This survey addresses the subject of bilateral teleoperation, a research stream with more than 50 years of history and one that continues to be a fertile ground for theoretical exploration and many applications.
1,584 citations
"Enhancement of Stability and Transp..." refers background in this paper
...Consequently, implementation of even well acceptable controllers still leaves the system with unwanted oscillations and inaccurate force feedback [16]....
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...It is already shown in sections IA and IB how state-of-the-art techniques [7]–[16] achieve proper signal transmission at stage 2....
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...An exhaustive list of all such control techniques is presented in [16]....
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TL;DR: In this article, a physically motivated, passivity-based formalism is used to provide energy conservation and stability guarantees in the presence of transmission delays, and an adaptive tracking controller is incorporated for the control of the remote robotic system and can be used to simplify, transform or enhance the remote dynamics perceived by the operator.
Abstract: A study is made of how the existence of transmission time delays affects the application of advanced robot control schemes to effective force-reflecting telerobotic systems. This application best exploits the presence of the human operator while making full use of available robot control technology and computing power. A physically motivated, passivity-based formalism is used to provide energy conservation and stability guarantees in the presence of transmission delays. The notion of wave variable is utilized to characterize time-delay systems and leads to a configuration for force-reflecting teleoperation. The effectiveness of the approach is demonstrated experimentally. Within the same framework, an adaptive tracking controller is incorporated for the control of the remote robotic system and can be used to simplify, transform, or enhance the remote dynamics perceived by the operator. >
1,286 citations
23 May 1990
TL;DR: In this article, a preliminary study of what role recent results in adaptive robot control and the understanding of time-delays may play in the development of effective telerobotics systems, which would best exploit the presence of the human operator while making full use of available robot control technology and computing power.
Abstract: Telerobotics, the body of science and technology which bridges human control and purely autonomous machines, is expected to be a merging point of modern developments in robotics, control theory, cognitive science, machine design, and computer science. Besides traditional applications in space, subsea, and handling of hazardous material, many new potential uses of advanced telerobotic systems have recently been suggested or explored, such as safety applications or microsurgery. This paper is a preliminary study of what role recent results in adaptive robot control and the understanding of time-delays may play in the development of effective telerobotics systems, which would best exploit the presence of the human operator while making full use of available robot control technology and computing power. The key paradigm it explores is that of simplifying, transforming, or enhancing the remote dynamics perceived by the operator by proper use of adaptive robot control techniques and tools from passivity theory.
936 citations