A Passivity-based Nonlinear Admittance Control with Application to Powered Upper-limb Control under Unknown Environmental Interactions

This paper presents an admittance controller based on the passivity theory for a powered upper-limb exoskeleton robot which is governed by the nonlinear equation of motion. Passivity allows us to include a human operator and environmental interaction in the control loop. The robot interacts with the human operator via F/T sensor and interacts with the environment mainly via end-effectors. Although the environmental interaction cannot be detected by any sensors (hence unknown), passivity allows us to have natural interaction. An analysis shows that the behavior of the actual system mimics that of a nominal model as the control gain goes to infinity, which implies that the proposed approach is an admittance controller. However, because the control gain cannot grow infinitely in practice, the performance limitation according to the achievable control gain is also analyzed. The result of this analysis indicates that the performance in the sense of infinite norm increases linearly with the control gain. In the experiments, the proposed properties were verified using 1 degree-of-freedom testbench, and an actual powered upper-limb exoskeleton was used to lift and maneuver the unknown payload.Comment: Accepted in IEEE/ASME Transactions on Mechatronics (T-MECH

Improvement on work measurement at Pau Mira Frozen Food Industry

The record of highest sales for one day is 20000 buns and the manpower for Pau Mira factory is only 18 persons. Special feature for Pau Mira is about the full of stuffing and many choices of flavor. Hot selling bun flavor is red bean bun and chocolate bun. For example, Bun Mira contains many flavors such as red bean bun, coconut, yam, chocolate, chicken, durian and it is enables to be food supplies to West Malaysia, not only limited to area Pagoh. The workflow for Pau Mira factory includes ingredient selection, dough kneading, and bun formation, fermentation, steaming, cooling and packaging. Table 5.1 shows the process of making pau started from dough kneading until the packaging process

A multi-touch interface for multi-robot path planning and control

In the last few years, research in human-robot interaction has moved beyond the issues concerning the design of the interaction between a person and a single robot. Today many researchers have shifted their focus toward the problem of how humans can control a multi-robot team. The rising of multi-touch devices provides a new range of opportunities in this sense. Our research seeks to discover new insights and guidelines for the design of multi-touch interfaces for the control of biologically inspired multi-robot teams. We have developed an iPad touch interface that lets users exert partial control over a set of autonomous robots. The interface also serves as an experimental platform to study how human operators design multi-robot motion in a pursuit-evasion setting

Interest of the dual hybrid control scheme for teleoperation with time delays

A new scheme of teleoperation called "dual hybrid control" is described. It is shown that telepresence is increased compared to traditional force feedback schemes. It is particulary well suited for time delay teleoperation

Multiobjective control of a four-link flexible manipulator: A robust H∞ approach

Copyright [2002] IEEE. This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of Brunel University's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to [email protected]. By choosing to view this document, you agree to all provisions of the copyright laws protecting it.This paper presents an approach to robust H∞ control of a real multilink flexible manipulator via regional pole assignment. We first show that the manipulator system can be approximated by a linear continuous uncertain model with exogenous disturbance input. The uncertainty occurring in an operating space is assumed to be norm-bounded and enter into both the system and control matrices. Then, a multiobjective simultaneous realization problem is studied. The purpose of this problem is to design a state feedback controller such that, for all admissible parameter uncertainties, the closed-loop system simultaneously satisfies both the prespecified H∞ norm constraint on the transfer function from the disturbance input to the system output and the prespecified circular pole constraint on the closed-loop system matrix. An algebraic parameterized approach is developed to characterize the existence conditions as well as the analytical expression of the desired controllers. Third, by comparing with the traditional linear quadratic regulator control method in the sense of robustness and tracking precision, we provide both the simulation and experimental results to demonstrate the effectiveness and advantages of the proposed approach

Farewell to Chalmers' Zombie - The 'Principle Self-Preservation' as the Basis of 'Sense'

My argument is that Chalmers' zombie fiction and his rigid-designator-argument going back on Kripke comes down to a petitio principii. Rather, at the core it appears to be more related to the essential 'privacy' of the phenomenal internal perspective. In return for Chalmers I argue that the 'principle self-preservation' of living organisms necessarily implies subjectivity and the emergence of sense. The comparison with a robot proves instructive. The mode of 'mere physical' being is transcended if, in the form of phenomenal perception, sense appears on the stage of higher animals – a transition explained here as an emergence phenomenon based on the systemic co-operation of perception, valuation and action ('perc-val-act system'). Some fundamental considerations are added: Those consequences implied by the principle self-preservation reveal the natural-biological origin of the organism – primarily seeming a more insignificant circumstance – as a momentous fundamental difference (end-in-itself-character, subjectivity, constitution of sense) compared to technical artefacts (robot). And the emergentist approach indicates the – maybe paradoxical – possibility of a dualism of physical and psychical phenomena in an overall physical system, that is not dualistic at the same time

Vine Robots: Design, Teleoperation, and Deployment for Navigation and Exploration

A new class of continuum robots has recently been explored, characterized by tip extension, significant length change, and directional control. Here, we call this class of robots "vine robots," due to their similar behavior to plants with the growth habit of trailing. Due to their growth-based movement, vine robots are well suited for navigation and exploration in cluttered environments, but until now, they have not been deployed outside the lab. Portability of these robots and steerability at length scales relevant for navigation are key to field applications. In addition, intuitive human-in-the-loop teleoperation enables movement in unknown and dynamic environments. We present a vine robot system that is teleoperated using a custom designed flexible joystick and camera system, long enough for use in navigation tasks, and portable for use in the field. We report on deployment of this system in two scenarios: a soft robot navigation competition and exploration of an archaeological site. The competition course required movement over uneven terrain, past unstable obstacles, and through a small aperture. The archaeological site required movement over rocks and through horizontal and vertical turns. The robot tip successfully moved past the obstacles and through the tunnels, demonstrating the capability of vine robots to achieve navigation and exploration tasks in the field.Comment: IEEE Robotics and Automation Magazine, 2019. Video available at https://youtu.be/9NtXUL69g_