A real-time joint trajectory planner for dynamic walking bipeds in the sagittal plane

Abstract

A real-time joint trajectory generator for planar walking bipeds is proposed. This trajectory planner generates dynamically stable motion patterns by using a set of objective locomotion parameters as its input, and by tuning and exploiting the natural upper body dynamics. The latter can be determined and manipulated by using the angular momentum equation. Basically, trajectories for hip and swing foot motion are generated, which guarantee that the objective locomotion parameters attain certain prescribed values. Additionally, the hip trajectories are slightly modified such that the upper body motion is steered naturally, meaning that it requires practically no actuation. This has the advantage that the upper body actuation hardly influences the position of the Zero Moment Point. The effectiveness of the developed strategy is demonstrated by simulation results.

Controlling a bipedal walking robot actuated by pleated pneumatic artificial muscles

“…In the future the method developed by Vermeulen 18 will be used to achieve faster walking. Here the trajectory planner generates motion patterns based on two specific concepts, being the use of objective locomotion parameters, and exploiting the natural upper body dynamics by manipulating the angular momentum equation.…”

Novel Robotic Applications using Adaptable Compliant Actuation. An Implementation Towards Reduction of Energy Consumption for Legged Robots

“…These parameters are calculated by a high level path planning control unit, which is beyond the scope of the current research. The trajectories of the leg links are represented by polynomials and are calculated by a simplified version of the method developed by Vermeulen (Vermeulen et al, 2005). The upper body and hip velocity is held constant in this case, which is valid for low walking speeds.…”

Active disturbance rejection for walking bipedal robots using the acceleration of the upper limbs

“…A few methods involve varying the step time, stride, or speed of the walk, 10,11 however this method can prove problematic for certain situations, such as the stepping stone problem where the biped must step on certain locations. Modification of the humanoid's trunk or waist motion has been studied, [12][13][14] and even exploiting the upper body's natural dynamics in its control 15 has been considered. Modification of the motion of the robot's base link of the stance leg 16 has been introduced as well.…”