Legged Robot Force-Balance Control During Whole-Body Manipulation
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Solution Overview
Problem
Existing robots require static balance establishment before operating end-effectors, limiting simultaneous movement and task performance, as they cannot dynamically balance while moving and manipulating objects.
Innovation Solution
A robot system with a control system that dynamically balances its legs to maintain whole-body manipulation, allowing end-effectors to operate while moving by coordinating lower and upper body control systems to balance reaction forces and moments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the robot establishes static balance before operating end-effectors, then the robot maintains stable balance, but the robot cannot perform simultaneous movement and task performance
Solution Approach 1:
The patent transitions from static balance to dynamic balance by continuously adjusting leg forces and moments during movement. The lower body control system dynamically modifies reaction forces at the contact surface to maintain balance while the robot moves and operates end-effectors simultaneously, rather than requiring pre-established static balance.
Solution Approach 2:
The patent calculates required reaction forces and moments in advance based on predicted end-effector operations and robot motion trajectories. The lower body control system prepares balance adjustments before movements occur, enabling coordinated whole-body manipulation without sacrificing stability.
2Adaptability or versatility
If the robot operates end-effectors while moving, then the robot achieves whole body manipulation, but the robot must coordinate multiple control systems increasing complexity
Solution Approach 1:
The patent merges upper body control and lower body control into a unified whole-body control framework. The control system integrates end-effector task requirements with balance maintenance, coordinating both upper and lower body movements as a single integrated system rather than separate independent controls.
Solution Approach 2:
The patent divides the control system into distinct upper body and lower body control components that communicate through defined interfaces. The lower body control system specifically manages reaction forces and moments at the contact surface, while the upper body control system manages end-effector operations, allowing modular coordination of complex functions.
3Ease of operation
If the robot uses dynamic balance with leg reaction forces, then the robot resembles human-like motion, but the robot must continuously adjust forces increasing control difficulty
Solution Approach 1:
The patent implements continuous feedback loops where the control system monitors actual reaction forces and moments from the contact surface and compares them with desired values. The lower body control system adjusts leg forces in real-time based on this feedback to maintain dynamic balance, enabling human-like motion while managing control precision through closed-loop regulation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables robots to maintain balance and perform tasks with end-effectors during movement, resembling human-like motion by dynamically controlling leg reaction forces to support end-effector operations.
Implementation Method 1
When the legs contact a surface (e.g., ground surface), the legs apply forces to the surface and experience reaction forces from the surface
Implementation Method 2
The lower body control system operates the one or more legs so that the second intermediate body linear force balances the first intermediate linear force and the second intermediate body moment balances the first intermediate body moment
Data Source
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AI summary
A robot system (400) includes: an upper body section (408b) including one or more end-effectors (422, 424); a lower body section (408a) including one or more legs (404, 406); and an intermediate body section (408c) coupling the upper and lower body sections. An upper body control system (417b) operates at least one of the end-effectors. The intermediate body section experiences a first intermediate body linear force and/or moment based on an end-effector force acting on the at least one end-effector. A lower body control system operates (417a) the one or more legs. The legs experience respective surface reaction forces. The intermediate body section experiences a second intermediate body linear force and/or moment based on the surface reaction forces. The one or more legs operate so that the second intermediate body linear force balances the first intermediate linear force and the second intermediate body moment balances the first intermediate body moment.