T4C | Robot Actuation | | T4D | SALA BIANCA | 16:30―18:10 | SALA TURCA | Hami Kazerooni, USA | CHAIR | Thomas Kurfess, USA | Giovanni Legnani, Italy | CO-CHAIR | Yoshio Yamamoto, Japan | Control Problems in Underactuated Manipulators
Alessandro De Luca, Stefano Iannitti, Raffaella Mattone, Giuseppe Oriolo, Università di Roma "La Sapienza", Italy
We discuss some recent control techniques for underactuated manipulators,a special instance of mechanical systems having fewer input commands than degrees of freedom.This class includes robots with passive joints,elastic joints,or .exible links.Structural system properties are investigated showing that robots with passive joints are the most di .cult to control.With reference to these,solutions are proposed for the typical problems of trajectory planning and tracking,and of set-point regulation.The relevance of nonlinear control techniques such as dynamic feedback linearization and iterative state steering is clari .ed through illustrative examples. | 16:30―16:50 | Conceptual Design of Mechatronic Systems Supported by Semi-formal Specification
Jürgen Gausemeier, Martin Flath, Stefan Möhringer, Heinz Nixdorf Institute, Germany
Mechatronics - the synergetic integration of different engineering domains can create new products and stimulate innovative solutions. In order to yield this potential experts from different engineering domains need a common method to specify results during the early stage of product conceptualisation. This method could create the base for cross-domain communication and efficient cooperation. In this way the potential of mechatronics can be realized. The article presents an integrated method for the conceptual design of mechatronic products. It comprises a new semi-formal specification language for the modelling of functions. This language is closely related to the semi-formal modelling of principle solutions …
| Stabilization and Output Tracking for Underactuated Mechanical Systems with Inequality State Constraints
Herbert G. Tanner, Kostas J. Kyriakopoulos, National Technical University of Athens, Greece
The paper presents a method to determine the feasibility of stabilization to an equilibrium manifold or exact ouput tracking for underactuated mechanical systems that are subject to inequality state constraints. Even for minimum phase systems internal dynamics may evolve in an unacceptable way and has to be confined within certain limits. Such restrictions arise in deformable object manipulation tasks. It is shown that the problem of output tracking under inequality state constraints is equivalent to ouput tracking with bounded input. The paper provides sufficient conditions for exact ouput tracking and stabilization to an equilibrium manifold that guarantee that internal dynamics is bounded with adjustable bounds. | 16:50―17:10 | Alternatives in Precise Load Motion Control of Two-Mass Servomechanisms
Gianni Ferretti, Gianantonio Magnani, Paolo Rocco, Polit. Milano, Italy
Load motion control in high precision elastic servo systems is addressed in this paper. It is assumed that only the motor position measurement is available to close control loops. Four controllers are compared: a conventional PID; a state space plus feedforward controller with integral action on the motor position measure; a second state space plus feedforward controller with integral action on the estimate of the load position; a pole assignment controller designed based on input-output models. The essential elements for the design of the controllers are given. Detailed simulation analysis is used to compare the controllers from several points of view (setpoint tracking, robustness, disturbance rejection, friction induced limit cycles). Experiments performed on a prototype servo will be discussed as well. |
Massively Parallel Actuation
Po-hua Yang, Ohio State Univ., Kenneth J. Waldron, Stanford Univ., USA
The objective of the work described in this paper is the examination of the design and control opportunities presented by systems with large numbers of small, two-state actuators acting in parallel. An array of two-state actuators, i.e. a bundle of binary actuators, can be regarded as a simplified model of biological muscle. In recent years, the development of MEMS (Micro-Electromechanical Systems) has shown a great potential for building mechanical elements in a very small scale. However, there are some other issues for integrating a parallel array system that cannot be solved by advances of material research alone. From the mechanical designer’s point of view, large numbers of active elements have to be deployed at appropriate locations in the system. For control purposes, if a binary system is intended, the mathematical model can be very different from that of ….
| 17:10―17:30 | Modeling, Design and Control of a Portable Washing Machine during the Spinning Cycle
Evangelos Papadopoulos, Iakovos Papadimitriou, National Technical University of Athens, Greece
This paper presents a simplified three-dimensional dynamic model of a horizontal-axis portable washing machine. This model is used to predict the verge of walking instability during the spinning cycle. Next, two novel methods of stabilization are presented. The design-based method reduces the instability and is cost effective. The control-based method eliminates instability and vibrations and is associated with active balancing. Both methods satisfy the current trend towards portable, lightweight full-feature washing machines. | SCID — A Non-actuated Robot for Walls Exploration
Domenico Longo, Giovanni Muscato, Università di Catania, Italy
In this paper a control methodology applied to a passive mechanical system is described. The SCID (Sliding Climbing Inspection Device) has been designed to slide down over a ferromagnetic vertical surface, using two electromagnets; the on-board electronics and the control algorithm used, allow the system to control its velocity and trajectory. The system has been experimentally tested and a simplified mathematical model has been computed.
| 17:30―17:50 | A Personal Robot for Mechatronic Application Programmers—The Role of Automatic Storage Reclamation and Programming Languages in the Lifetime of a Safe Mechatronic System
Roberto Brega, Felix H. Wullschleger, ETHZ, Switzerland
A software system can be called a safe-system with respect to dynamic memory,when it supports only strong-typing and it doesn’t allow for the manual disposal of dynamic memory.The first aspect guarantees that untyped,potentially dangerous operations are caught by the compiler or by run-time checks.The second issue is solved by the utilisation of an automatic memory reclamation scheme,i.e.a garbage collector. In this paper we present the implementation of these strategies in the real-time operating system XO/2,and how they have contributed to the realisation of the Mobile Mail Distribution System MoPS,developed at the Institute of Robotics of the ETH Zürich,Switzerland. |
Mircea Badescu, Constantinos Mavroidis, Rutgers University, USA
This paper presents the concept, design, analytical modeling and experimental prototype for a new "smart connector", which provides electrical and mechanical connection between components of a system, specifically robotic modules. The connector includes plug and receptacle components. The plug has a central pin surrounded by a plurality of lamellae. The lamellae have an end connected to the base and a free end. A Shape Memory Alloy (SMA) actuator is positioned about the lamellae of the plug for controlling the movement of the free end of the lamellae. The receptacle has a pin housing corresponding to the central pin of the plug. Additionally, the receptacle includes a plurality of lamellae for mating with the plug lamellae. Like the plug, the receptacle includes an SMA actuator for controlling movement of the receptacle lamellae. The plug lamellae and the receptacle …
| 17:50―18:10 | Design Requirements and Reference Trajectory Generation for a Copier Paperpath
Carlo Cloet, Masayoshi Tomizuka, Roberto Horowitz, UC Berkeley, USA
This paper presents a new approach to introducing closed loop control in a copier paperpath in order to achieve robust high-speed media handling. The basic idea exploits periodicity in the relative position of correctly fed sheets and their corresponding images. It is shown that the periodic behavior allows to design polynomial position reference trajectories for sheets as a function of their initial position error. Only longitudinal position errors are considered. By measuring sheet positions and using closed loop control to track the reference trajectories position errors can be successfully removed. In addition to the reference trajectories the paper also offers a design strategy that minimizes the required paperpath length while satisfying given bounds on sheet velocities and accelerations. Two … |
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