DYNAMIC CONTROL ALGORITHM FOR A BIPED ROBOT (original) (raw)
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Walking trajectory control of a biped robot Technical report B04-18
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.
Walking trajectory control for a biped robot
2009
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.
Control Algorithm for Stable Walking of Biped Robots
This paper deals with the stable walking of biped robots. The presented control algorithm enables a biped to perform stable walking without using any precomputed trajectories. The algorithm merges gait trajectory generation and control, and can be used for global control, for local control along an existing trajectory as well as for online computation of gait trajectories for stable walking. The inputs for the algorithm are a few parameters such as walking speed and step size. The performance of the algorithm is demonstrated by simulation.
Polynomial trajectory algorithm for a biped robot
Building trajectories for biped robot walking is a complex task considering all degrees of freedom (DOFs) commonly bound within the mechanical structure. A typical problem for such robots is the instability produced by violent transitions between walking phases in particular when a swinging leg impacts the surface. Although extensive research on novel efficient walking algorithms has been conducted, falls commonly appear as the walking speed increases or as the terrain condition changes. This paper presents a polynomial trajectory generation algorithm (PTA) to implement the walking on biped robots following the cubic Hermitian polynomial interpolation between initial and final conditions. The proposed algorithm allows smooth transitions between walking phases, significantly reducing the possibility of falling. The algorithm has been successfully tested by generating walking trajectories under different terrain conditions on a biped robot of 10 DOFs. PTA has shown to be simple and suitable to generate real-time walking trajectories, despite reduced computing resources of a commercial embedded microcontroller. Experimental evidence and comparisons to other state-of-the-art methods demonstrates a better performance of the proposed method in generating walking trajectories under different ground conditions.
Dynamic Control Strategy of a Biped Inspired from Human Walking
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 Control Strategy for a Dynamic Walking Biped with Articulated Legs
In this paper, a high-level real-time control strategy for a bipedal walking robot is presented. The considered motion is a steady walking pattern with instantaneous double support phase. The presented algorithm introduces a number of objective locomotion parameters which char- acterize the steps, and at the same time controls the upper body motion. Polynomial trajectories are designed to be tracked by the different controllers of the leg links. These trajectories deal with the fact that the ankle torque is limited by the physical length of the foot. The motion of the upper body is quasi naturally steered by using the angular momentum equation in a convenient way. Only a small ankle torque has to be added to reach exactly the desired conditions for the upper body. Promising results of the simulations are shown.
SIMULATION and CONTROL of a BIPED WALKING ROBOT using KINEMATIC and DYNAMIC MODELLING
In this article, we intend to consider the behavior and control of a biped walking robot using kinematic and dynamic relations. At first, by using simple model of humanoid robot and essentional equations the angles, angular velocities, accelerations of motors and required torques for moving on a straight line are find out. In the second step considering numerical values of the robot parameters and constructing the dynamic model the abilities of robot are examined and simulated.
Generation of walk transient trajectories for a biped robot
1999
We want to control an anthropomorphic biped robot to make it walk in its environment. For this purpose, we need complete walk trajectories. We start with cyclic trajectories obtained with motion capture on a human. Then, we want to generate transient trajectories with a fast and on-line method, in order to complete cyclic trajectories provided by motion capture. We thus use a method based on cubic polynomials. We apply this method on a human walk trajectory, to compute start and stop transient trajectories for the robot.
Modeling and control of biped robot dynamics
Robotica, 1999
This paper addresses the problem of modeling biped dynamics and the use of such models for the control of walking, running and jumping robots. We describe two approaches to dynamic modeling: the basic Lagrange approach and the non-regular dynamic approach. The new non-regular dynamic approach takes into account discontinuities due to rigid contact between punctual feet and the ground without computing the exact impact time. The contact is close to the physical situation given by non-linear laws (impenetrability, non-smooth contact and real friction cone). Contact dynamics can be well managed with an accurate dynamic model that respects energy consistency during all the phases encountered during a step (0, 1 or 2 contacts). With this model, we can first study the equilibrum of a biped standing on one foot by a linearisation method. In the second stage, the unified modelized equation is used to establish a general control frame based on non-regular dynamical decoupling. A comparison i...
2001
A 3-dimensional computer model of sustainedbipedal walking is presented. It is intended be used as adevelopment tool for walking controllers. The directdynamic simulation has 8 segments, 19 degrees offreedom and is driven by prescribed joint moment andstiffness trajectories. Limited feedback in the form of aproportional-derivative controller provides upper bodystability and allows walking to be sustained indefinitely.The joint moment and stiffness trajectories are specifiedin coarse block segments. By changing the intensity of hipextensor activity during terminal stance the walking stridelength is modulated.