On active controls for a biped mechanism

Humanoid Robots, 2009

Intelligent Engineering Systems through Artificial Neural Networks Volume 18, 2008

In this paper, we show that a biped robot can walk dynamically using a simple control technique inspired from human locomotion. We introduce four critical angles that affect robot speed and step length. Our control approach consists in tuning the PID parameters of each joint in each walking phase for introducing active compliance and then to increase stability of the walk. We validated the control approach to a dynamic simulation of our 14DOF biped called ROBIAN. A comparison with human walking is presented and discussed. We prove that we can maintain robot stability and walk cycle's repetition without referencing a predefined trajectory or detecting the center of pressure. Results show that the walk of the biped is very similar to human one. A power consumption analysis confirms that our approach could be implemented on the real robot ROBIAN.

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.

Proceedings of IEEE International Conference on Evolutionary Computation, 1996

This paper deals with the problem of biped locomotion control in the sagittal plane. A model of the biped with five linked rigid bodies is developed to simulate the system dynamics This model has four joints of revolution, one at each link. A Steudy State Genetic Algorithm is used to find the necessary torques in each joint to obtain a desired trajectory for the biped's trunk center of mass. Each of the individuals in the GA consists ofa set of command sequences given to the biped, the jitness being obtained through simulation of the resulting motion and its comparison to the desired trajectory.

Proceedings of the 2005 IEEE International Conference on Robotics and Automation, 2005

The objective of this study is to obtain optimal cyclic gaits for a biped without actuated ankle. For the walking, the gait is composed of successive single support phases and instantaneous double support phases that are modeled by passive impact equations. The legs swap their roles from one single support phase to the next one. During each phase the evolution of the joints variables is assumed to be polynomial functions of a scalar path parameter. The coefficients of the polynomial functions are chosen to optimise a torque criterion and to insure a cyclic motion for the biped. Furthermore, the optimal gait is defined with respect to given performances of actuators. The torques and velocities at the output of the gearbox are bounded. For this study, the physical parameters of a prototype are used. Initial starting motions that are composed of a double support and a transitional single support are also defined.

TJPRC, 2014

It is simple for humankind to steadily walk on different terrain, but it is hard to achieve a human-like gait for bipedal walking robots due to their complex dynamics. In general, there are two approaches towards controlling a biped robot: static and dynamic walking. In this paper, we demonstrate the dynamic walking approach for controlling a biped robot. In this approach, the walker moves only under the gravitational force. The loss energy of during the walk will recover only by the gravity. The walker will have a stable gait over the course of several steps for that reason there is no need for PDBR to be stabilized in each of its steps. It can stably walk over a gentle slope. In this paper, we explain the steps of mathematical modeling which analogues to a double inverted pendulum, the impact equations for heel-strike and the stepwise analysis of walking of a passive biped. This paper shows the graphical approach to analysis the symmetric gait for the linear model of passive dynamic bipedal robot (PDBR).

Proceedings of the 10th ECCOMAS Thematic Conference on MULTIBODY DYNAMICS, 2021

Human locomotion involves a complex integration of muscles activity, central nervous system, and sensory information. Attempts to describe and understand the biomechanics of human locomotion have been made experimentally and mathematically (simulation). Mathematically, biped models with various complexities have been used to study human locomotion using different numerical methods and many features of human locomotion have been verified. In this paper, an optimization based prediction of human gait with its essential features using simple biped with torso is formulated. The biped can "qualitatively" mimic many features of human locomotion including the general behavior of human gait during running and walking.

Proceedings 2003 IEEE/ASME International Conference on Advanced Intelligent Mechatronics (AIM 2003), 2003

Methods for modeling, simulation and optimization of the dynamics, stability, and performance of humanoid robots are presented in this paper. Optimal control trajectory following by joint-level control combined with an online compensation method using Jacobians is proposed. The kinematic design, dynamic properties, hard-and software architecture for an autonomous biped, and experimental results are presented.

IFAC Proceedings Volumes, 2013

Analytical techniques are presented for the motion planning and control of a 10 degree-of-freedom biped walking robot. From the Denavit-Hartenberg method and Newton-Euler equations, joint torques are obtained in terms of joint trajectories and the inverse dynamics are developed for both the single-support and double-support cases. Physical admissibility of the biped trajectory is characterized in terms of the equivalent force-moment and zero-moment point. This methodology has been used to obtain stability of walking biped robot Archie developed in IHRT. A simulation example illustrates the application of the techniques to plan the forward-walking trajectory of the biped robot.

Lecture Notes on Software Engineering, 2013

 Abstract-This paper concentrates on three important points: the selection of the suitable direct method used for suboptimal control of the biped robot, the selection of the appropriate nonlinear programming (NLP) algorithm that searches for the global minimum rather than the local minimum, and the effect of different constraints on the energy of the biped robot. To perform the mentioned points, the advantages and disadvantages of the optimal control methods were illustrated. The inverse-dynamics based optimization is preferred because of the ability to convert the original optimal control into algebraic equations which are easy to deal with. The inverse-dynamics-based optimization was classified as spline and the finite difference based optimization. Due to the easy use of the latter, it was used for investigating seven cases with different constraints for 6-DOF biped robot during the single support phase (SSP). Hybrid genetic-sequential quadratic programming (GA-SQP) was used for simulation of the target robot with MATLAB. It can be concluded that more imposed constraints on the biped robot, more energy is needed. In general, more energy can be required in the case of (1) restriction of the swing foot to be level to the ground and (2) reducing the hip height or constraining the hip to move in constant height.