Control of the Underactuated Inertia Wheel Inverted Pendulum for Stable Limit Cycle Generation

This paper deals with a control approach dedicated to stable limit cycle generation for underactuated mechanical systems. The proposed approach is based on partial nonlinear feedback linearization and dynamic control for optimal periodic reference trajectories tracking. The computation of the reference trajectories is performed in order to optimize the behavior of the whole dynamics of the system and especially its zero dynamics at the end of each cycle. Simulation results as well as experiments show the performance and the efficiency of the proposed control scheme.     

Manipulative difficulty of a mobile robot pushing and towing multiple trailers

The change of difficulty in manipulating a tractor pushing or towing multiple trailers is investigated in this paper. This difficulty varies if physical parameters such as the position of the joint or the number of the trailers is changed. The present authors focus on this change. A quantitative measure of the manipulative difficulty [manipulative difficulty index(MDI)] of tractor-trailers system is introduced. In addition, quantitative comparisons of typical examples of the changes of the physical parameters of tractor-trailers are presented.     

Robot phonotaxis in the wild: a biologically inspired approach to outdoor sound localization

Cricket phonotaxis (sound localization behavior) was implemented on an autonomous outdoor robot platform inspired by cockroach locomotion. This required the integration of a novel robot morphology (Whegs) with a biologically based auditory processing circuit and neural control system, as well as interfacing this to a new tracking device and software architecture for running robot experiments. In repeated tests, the robot is shown to be capable of tracking towards a simulated male cricket song over natural terrain. Range fractionation and gain control were added to the auditory control circuit in order to deal with the substantial change in amplitude of the signal as the robot approached the outdoor sound stimulus. We also discuss issues related to acoustic interference from motor noise, the need for a motor feedback mechanism to better regulate the drive signal and plans for future work incorporating additional sensory systems on this platform.     

Pilot control of an auto-balancing two-wheeled cart

The control system of an auto-balancing two-wheeled cart (ABTWC) is inherently unstable, displays a non-minimum phase and can be piloted by a joystick that has 2 d.o.f. This paper employs a state feedback technique to design the stabilizing controller for an ABTWC and develops a pilot algorithm, i.e., differential steering, which converts two joysticks' commands into two torque directives for transportation. This allows the user to operate this cart linearly for both motion and orientation control via a joystick. Control examples are given to illustrate the feasibility and the effectiveness of the proposed controller and pilot algorithm.     

IRSN's experience feedback list for assessment of transport package design safety reports

Abstract

Since 1996, the Institute for Radiation Protection and Nuclear Safety (IRSN), the technical support organisation of the French Competent Authority for the safety of transport of radioactive materials, has recorded the list of the difficulties most frequently encountered during the assessment of the safety reports of package designs. This experience feedback list takes into account the most recent evolutions of the regulations and the latest technological knowledge. For instance the safety reports should include the analysis of the most unfavourable configurations such as the 1 m free drop onto the bar when the package is in oblique position, the 9 m drop test of a package with slapdown, the thermal dissipation under a tarpaulin or canopies, the brittle fracture analysis at –40°C. IRSN's experience feedback list for transport package designs, which is published annually, is used as a guide by applicants to improve their package design safety reports and by IRSN for their assessments. Recently, it has been integrated in the French transport applicant guide and in the European technical guide for drafting the package design safety reports.     

Fluid-Filled Soft-Bodied Amoeboid Robot Inspired by Plasmodium of True Slime Mold

This paper presents a fluid-filled soft-bodied amoeboid robot inspired by the plasmodium of the true slime mold. The significant features of this robot are 2-fold. (i) The robot has a fluid circuit (i.e., cylinders and nylon tubes filled with fluid), and a truly soft and deformable body stemming from real-time tunable springs — the former seals protoplasm to induce global physical interaction between the body parts and the latter is used for elastic actuators. (ii) A fully decentralized control using coupled oscillators with a completely local sensory feedback mechanism is realized by exploiting the global physical interaction between the body parts stemming from the fluid circuit. The experimental results show that this robot exhibits adaptive locomotion without relying on any hierarchical structure. The results obtained are expected to shed new light on the design scheme for autonomous decentralized control systems.