The bipedal saddle space: modelling and validation

Abstract

Better understanding of humans balance control is pivotal for applications such as bipedal robots and medical technologies/therapies targeting human locomotion. Despite the inverted pendulum model being popular to describe the bipedal locomotion, it does not properly capture the step-to-step transition dynamics. The major drawback has been the requirement of both feet on the ground that generates a discontinuity along the intersection of the potential energy surfaces produced by the two legs. To overcome this problem, we propose a generalised inverted pendulumbased model that can describe both single and double support phases. The full characterisation of the system potential energy allows the proposed model to drop the main limitation. This framework also enables to design optimal strategies for the transition between the two feet without the optimisation algorithms. The proposed theory has been validated by comparing the human locomotor strategies output of our planner with real-data from multiple experimental studies. The results show that our model generates trajectories consistent with human variability and performs better compared to existing well-known methods.

Analytic Model for Quadruped Locomotion Task-Space Planning

“…The section presents with the extension of the bipedal model proposed by Tiseo et al in [3], and the validation method used to test the model for quadrupeds. Fig.…”

“…The identification of efficient and effective planning strategies in unstructured environments is critical to the development of mobile robotics platform that can enter daily living environments to improve human life quality and take over dangerous tasks [1], [3] environments (e.g., deep mines, offshore oil rigs and disaster sites), offering both greater flexibility than wheeled robots and better stability characteristics compared to bipeds [1]. However, the high redundancy of the system kinematics implies a higher complexity in the planning stage, making the system less adaptable to sudden changes in the environment which trigger a replanning of the entire action.…”

Geometrical Postural Optimisation of 7-DoF Limb-Like Manipulators

“…However, null-space projections can be substituted in back-derivable systems by introducing a weak potential field in the joint space pulling the robot towards a reference configuration [3]. Whole-body controllers are used in planning and control loco-manipulation tasks in mobile robotics, where null-space projections are used to formulate the system equations used to generate the control commands [1,13,29,32,33].…”

Online Dynamic Trajectory Optimization and Control for a Quadruped Robot

“…There are also methods that do not utilize numerical optimization. In [16], a generalized inverted pendulum model based on the analysis of the potential energy surface in human locomotion is used to generate non-coplanar biped trajectories and was extended to quadruped trajectory planning in [17]. However, these methods do not consider friction cone constraints that are critical to stabilise locomotion upon uneven terrain.…”