Virtual Effector Trajectory Planning With Relaxed Contact Constraints

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Solution Overview

Problem

Current multi-contact motion planning methods for virtual characters are inefficient due to the separation of contact sequence and pose estimation steps, leading to suboptimal trajectory optimization and potential physical limitations such as joint overload or instability in robots.

Innovation Solution

A method that acquires a sequence of postures with contact points and kinematic poses, modifies constraint topologies, performs constraint relaxation, and applies a trajectory generation algorithm to generate an effector trajectory, allowing for inverse kinematics and real-time control signal output for improved motion planning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If multi-contact motion planning is divided into separate subtasks (contact sequence search, pose estimation, trajectory optimization), then computational complexity of each individual step is reduced, but interdependencies between steps are lost leading to suboptimal solutions and increased overall computation time

Engineering Contradiction:
Improvecomputational complexity of individual stepsVSAvoidoverall computation time and solution quality
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent merges the previously separate subtasks (contact sequence search, pose estimation, and trajectory optimization) into a unified multi-contact motion planning framework. This integration allows the system to consider interdependencies between all steps simultaneously, optimizing the entire motion planning process rather than treating each step independently, thereby reducing overall computation time and improving solution quality.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If contact candidates are determined first and then used for pose estimation, then the search space for contacts is managed efficiently, but the contact candidates cannot be adapted during subsequent pose estimation and trajectory optimization steps

Engineering Contradiction:
Improvemanageability of search spaceVSAvoidadaptability of contact candidates during optimization
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent implements a dynamic approach where contact candidates are not fixed after the initial search but are continuously adapted and refined during the pose estimation and trajectory optimization steps. This dynamic adaptation allows the system to adjust contact candidates based on emerging information from subsequent optimization steps, improving the overall quality of the motion plan while still maintaining computational efficiency through the initial structured search.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentUS11752623B2Simulating task performance of virtual characters
Publication Date: 2023.09.12 HONDA MOTOR CO LTD
  • US11752623B2 patent drawing
  • US11752623B2 patent drawing
  • US11752623B2 patent drawing

AI summary

A method and simulation system for controlling at least one effector trajectory for solving a predefined task by at least one virtual effector. The method includes acquiring a sequence of postures to modify at least one of a contact constraint topology and an object constraint topology, generating a set of constraint equations based on at least one of the modified contact constraint topology and the modified object constraint topology, performing constraint relaxation on the generated set of constraint equations to generate a task description including the relaxed set of constraint equations, generating the effector trajectory by applying a trajectory generation algorithm on the generated task description, performing an inverse kinematics algorithm on the generated effector trajectory for generating a control signal, outputting the control signal to an output device, and generating, by the output device, image information displaying the effector trajectory of the virtual effector based on the control signal.