Legged Robot Motion Control for Smooth Normal-Safe Switching
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Solution Overview
Problem
Existing legged robot motion control systems experience discontinuous motion and chattering when switching between normal and safe modes, leading to instability.
Innovation Solution
Implement a motion control unit that transitions between normal and safe motions stepwise using continuous and smoothly increasing/decreasing functions, such as sigmoid functions, to stabilize the robot's motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a control policy is determined after determination from sensor information using discrete switching, then the robot can respond quickly to safety conditions, but discontinuous motion and chattering occur at the boundary of determination conditions
Solution Approach 1:
The patent applies parameter changes by transitioning from discrete control policy switching to continuous parameter adjustment. Specifically, it uses a determination function that outputs continuous values and a switching control function that smoothly adjusts control parameters based on these continuous values, eliminating abrupt transitions while maintaining rapid response to safety conditions.
Solution Approach 2:
The patent introduces intermediary functions (determination function and switching control function) between sensor information and control policy execution. These intermediary functions continuously transform discrete safety determinations into smooth control transitions, preventing direct abrupt switching while preserving the underlying safety logic.
2Reliability
If discrete switching between normal and safe motion is implemented, then clear safety boundaries are enforced, but chattering occurs in the vicinity of determination condition boundaries
Solution Approach 1:
The patent changes the parameter representation from discrete binary switching to continuous parameter adjustment. The determination function produces continuous output values that reflect the degree of safety violation, and the switching control function uses these continuous values to smoothly adjust control parameters, maintaining safety enforcement without chattering.
Solution Approach 2:
The patent applies curvature by using smooth continuous functions (sigmoid functions or quadratic functions) instead of sharp discrete boundaries. These curved transition functions gradually shift control parameters as the system approaches safety boundaries, eliminating the abrupt angular transitions that cause chattering while preserving safety constraints.
3Stability of the object's composition
If continuous switching functions are used to smooth transitions, then motion continuity is improved, but the complexity of the control system increases
Solution Approach 1:
The patent segments the control system into distinct functional modules: a determination function module that evaluates safety conditions, and a switching control function module that adjusts parameters. This segmentation organizes the complexity into manageable, independently analyzable components while achieving smooth transitions.
Solution Approach 2:
The patent implements feedback by using the output of the determination function (which continuously evaluates the current state against safety boundaries) to dynamically adjust control parameters through the switching control function. This feedback mechanism automatically adapts the control behavior to current conditions, reducing the need for complex hard-coded transition logic.
Data Source
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AI summary
The present technology relates to an information processing apparatus, a motion control method, and a moving body that enable smooth switching between a normal motion and a safe motion for ensuring safety of a moving body. An information processing apparatus includes a motion control unit that causes a motion of a moving body to transition stepwise from one motion of a normal motion and a safe motion for ensuring safety of the moving body to another motion. The present technology is applicable to, for example, a legged robot.