Loading...

On Correlation of Dynamic Biped Locomotion and Dynamic Object Manipulation

Beigzadeh, Borhan | 2011

673 Viewed
  1. Type of Document: Ph.D. Dissertation
  2. Language: Farsi
  3. Document No: 42188 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Meghdari, Ali; Sohrabpour, Saeed
  7. Abstract:
  8. Dynamic Object Manipulation (DOM) and Dynamic Biped Locomotion (DBL) are certainly two major categories in robotics, which attract much attention of scientists. Their (hybrid) nonlinear dynamics usually make them challenging subjects to deal with. Such systems are often used as benchmarks to test new nonlinear control approaches or stability analyses. However, there is not a unified approach to both systems. Although it seems that DOM and DBL systems are completely different at first view, we deeply believe that essential similarities exist between these two robotic fields. In this dissertation, we study the correlation of DOM and DBL while addressing passive, underactuated, and fully actuated systems. In the first step of the research, the conceptual relation between DOM and DBL is studied. As a special case of DOM, Dynamic Nonprehensile Manipulation (DNM) of multibody objects using a series of sequential manipulators is taken into account. The concept of “multibody object” complicates the analysis by entering the dynamics of the object to the problem. However, its configuration can be controlled if enough actuators are added to the object. Having noticed that a biped uses two limbs with unilateral contact with the ground to perform locomotion, we focus on a special class of multibody objects with structural symmetry that have two arms as contact surfaces. This way, if the structure of the object is similar to that of a biped walker, a DNM system including zero DOF manipulators could be implemented where the object is manipulated by the ground. This can be a new interpretation of the walking. In fact, it is supposed that a biped walker is manipulated by the ground while walking. This approach is the main direction of this thesis. After defining and modeling a general DNM system, other corresponding aspects are also taken into account. In particular, the stability of the process is studied from two viewpoints: postural stability, and orbital stability. For postural stability, a new metric, namely PRI, is defined. It is discussed that when PRI is inside the convex hull of the contact surface of the object, the object does not rotate with respect to the manipulator. Three categories of DNM of multibody objects are then studied here; first, passive DNM which addresses systems having no actuator but still capable of manipulating passive objects; second, underactuated DNM that explores systems whose number of actuators is less than their DOF; finally, fully actuated DNM, which studies systems having enough actuators to control the configuration of the system. In this thesis, with the aid of several examples and simulation, it is showed how to model and implement these systems. Then the DNM concept is discussed to be a framework to construct models for different kinds of biped walkers. It is demonstrated that all corresponding aspects of a DBL system could be modeled based on this DNM framework. Specially, it is explained that the PRI is a general form which reduces to ZMP and FRI when the DNM reduces to DBL. Finally, by changing the parameters and specifications of the object, a biped model is constructed for each category. In other words, three models of biped walkers are studied using the DNM approach: a passive compass-gait walker, a point-feet walker with five-link structure, and a flat-feet, seven-link biped walker. Experiments support the results in some stages of the research.
  9. Keywords:
  10. Locomotion ; Bipedal Robot ; Dynamic Object Manipulation (DOM) ; Multibody Objects ; Dynamical Systems with Impact Effects ; Passive Systems

 Digital Object List

  • محتواي پايان نامه
  •   view

 Bookmark

No TOC