3-D Biped Robot Walking along Slope with Dual Length Linear Inverted Pendulum Method (DLLIPM)

Abstract

A new design method to obtain walking parameters for a three-dimensional (3D) biped walking along a slope is proposed in this paper. Most research is focused on the walking directions when climbing up or down a slope only. This paper investigates a strategy to realize biped walking along a slope. In conventional methods, the centre of mass (CoM) is moved up or down during walking in this situation. This is because the height of the pendulum is kept at the same length on the left and right legs. Thus, extra effort is required in order to bring the CoM up to higher ground. In the proposed method, a different height of pendulum is applied on the left and right legs, which is called a dual length linear inverted pendulum method (DLLIPM). When a different height of pendulum is applied, it is quite difficult to obtain symmetrical and smooth pendulum motions. Furthermore, synchronization between sagittal and lateral planes is not confirmed. Therefore, DLLIPM with a Newton Raphson algorithm is proposed to solve these problems. The walking pattern for both planes is designed systematically and synchronization between them is ensured. As a result, the maximum force fluctuation is reduced with the proposed method.

A simple control algorithm for controlling biped dynamic walking with stopping ability based on the footed inverted pendulum model

“…If the biped walking occurs on an unknown rough ground, the swing leg's height may be different to the stance leg's when touchdown for maintaining body height is unchanged, as well as in dual length linear inverted pendulum mode (DLLIPM). 21…”

A universal pattern generator for biped walking on 3D slopes

“…In this part, a universal method to generate patterns for a biped robot walking on a 3D slope is developed base on the DLLIPM concept [16]. The CoM motion in the DLLIPM is maintained horizontally in the coronal plane, thus, the ground reaction force is reduce compared with the LIPM.…”

“…6, the CoM motion in sagittal plane is described in Σ γ , the y (walking direction) trajectory of CoM is obtained by (15) (16). Equation (17) generate the z trajectory of CoM, which is just determined by the value of y.…”

“…As for walking along a slope, Fukuda et al presented a method of the stable motion generation based on learning with GAS having self-adaptive mutation and recurrent neural networks [15]. In 2013, Ali et al [16] proposed a new design method to achieve 3-D biped robot walking along slope with dual length linear inverted pendulum method (DLLIPM), in which a different height of pendulum was applied on the two legs and he proved the ground reaction force is reduced due to the CoM (Center of Mass) in the DLLIPM is maintained horizontal. However, without double support phase, the walking patterns he proposed are disharmony for the different displacement of CoM between two legs.…”

Analysis of balance control methods based on inverted pendulum for legged robots

“…In the paper [16] the method for obtaining walking parameters for biped robot moving along a slope is considered. The authors investigate a strategy to realize biped robot walking along a slope, when robot's centre of mass (CoM) is moved up or down during movement.…”