Walking trajectory control for a biped robot

A not trivial problem in bipedal robot walking is the instability produced by the violent transition between the different dynamic walk phases. In this work an dynamic algorithm to control a biped robot is proposed. The algorithm is based on cubic polynomial interpolation of the initial conditions for the robot’s position, velocity and acceleration. This guarantee a constant velocity an a smooth transition in the control trajectories. The algorithm was successfully probed in the bipedal robot “Dany walker” designed at the Freie Universität Berlin, finally a briefly mechanical description of the robot structure is presented

Action module planning and Cartesian based control of an experimental climbing robot

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1997.Includes bibliographical references (leaves 88-95).by David M. Bevly.M.S

Application of Product Design Concepts and Hybrid System Dynamics to Demonstrate Zeno Behavior and Zeno Periodic Orbits in a Physical Double Pendulum Setup

This thesis aims to explain how the concepts of functional modeling are implemented in the development and validation of real-world hybrid dynamic systems. I also discuss how control theory is integrated with the design process in order to understand the significance of periodic orbits on a simple dynamic system. Two hybrid system applications with different levels of complexity will be considered in this thesis – an anthropomorphic Bipedal walking robot and a Double Pendulum with a mechanical stop. The primary objectives of this project are to demonstrate the phenomena of Zeno and zeno periodic orbits in hybrid dynamic systems involving impacts. Initially, I describe the salient features of the product design procedure and then explain the significance of functional modeling as a part of this process. We then discuss hybrid dynamic systems and the occurrence of Zeno behavior in their mathematical form. Also, the necessary conditions for existence of Zeno and zeno equilibrium points are provided. Then the theory of completed Lagrangian hybrid systems is explained in detail. We then examine the two hybrid dynamic systems being considered for this project. Prior research undertaken on bipedal walking is explored to understand their design and achievement of stable walking gaits with appropriate actuation mechanisms. Based on this insight, a suitable design procedure is employed to develop the bipedal robot model. The desired actuation mechanisms for all the configurations considered for this model as well as the challenges faced in employing optimal actuation will be discussed. However, due to the high level of complexity of the bipedal robot model, a simpler hybrid dynamic system is considered to simplify fabrication and control of the model. This is the motivation behind designing and building the Double Pendulum model with a mechanical stop in an attempt to observe zeno behavior in this system. We begin by formally demonstrating that the “constrained” double pendulum model displays Zeno behavior and complete this Zeno hybrid system to allow for solutions to be carried past the Zeno point. The end result is periods of unconstrained and constrained motions in the pendulum, with transitions to the constrained motion occurring at the Zeno point. We then consider the development of a real physical pendulum with a mechanical stop and introduce non-plastic impacts. Later, we verify through experimentation that Zeno behavior provides an accurate description of the behavior of the physical system. This provides evidence to substantiate the claim that Zeno behavior, while it does not technically occur in reality, provides an accurate method for predicting the behavior of systems undergoing impacts and that the theory developed to understand Zeno behavior can be applied to better understand these systems

Recurrent Neural Network Approaches For Biped Walking Robot Based On Zero-moment Point Criterion

The main objective of this paper is to use a recurrent neural network (RNN) to determine the trunk motion for a biped-walking machine, based on the zero-moment point (ZMP) criterion. ZMP criterion can be used to plan a stable gait for a biped-walking machine that has a trunk (inverted pendulum). So, a RNN is trained to determine a compensative trunk motion that makes the actual ZMP get closer to the planned ZMP. In this context, an identification scheme is presented to obtain the vector of parameters of the RNN. A first order standard back-propagation with momentum (BPM) is used to adjust free parameters for the network. Artificial neural network brings up important features for function approximation. This was the main reason to use an RNN to determine the trunk motion. The proposed scheme is simulated on a 10-degree-of-freedom biped robot. The results confirm the convergence of the proposed scheme, proving this is a new way to solve this classical problem in the biped-walking machine area.2516978Bezerra, C.A.D., (2002) A Biped Robot Machine Design for Walking in an Unknown Environment, , School of Mechanical Engineering, the State University of Campinas. Doctoral thesis, in PortugueseGoswami, A., Postural stability of biped robots and the foot-rotation indicator (FRI) point (1999) The International Journal of Robotics Research, 18 (6), pp. 523-533. , JuneJuang, J.-G., Fuzzy neural network approaches for robotics gait synthesis (2000) IEEE Transactions on Systems, Man, and Cybernetics - Part B: Cybernetics, 30 (4). , August 2000Li, Q., Learning control of compensative trunk motion for biped walking robot based on ZMP stability criterion (1992) Proceedings of the 1992, IEEE/RSJ International Conference on Intelligent Robots and Systems, , Ralei gh, NC. July, 7-10, 1992Shih, C.-L., Inverse kinematics and inverse dynamics for control of a biped walking machine (1993) Journal of Robotics Systems, 10 (4), pp. 531-555Von Zuben, F.J., (2000) Notas de Aula do Curso IA353 - Redes Neurais, , UNICAMP/FEEC/DCAYamagushi, J.-I., Development of a biped walking robot compensative for three-axis by trunk motion (1992) Proceedings of the 1993, IEEE/RSJ International Conference on Intelligent Robots and Systems, , Yokohama, Japan. July, 26-30, 1993Takanashi, A., Robot biped walking stabilized with trunk motion (1989) Proceedings of ARW on Robotics and Biological Syste