Robot Leg Swing Trajectories for Timed Touchdown and Balance
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Solution Overview
Problem
Legged robots face challenges in navigating constrained environments efficiently while avoiding obstacles and maintaining balance, as existing navigation methods often result in slow and arduous movements with frequent collisions and loss of balance.
Innovation Solution
A method for planning leg swing trajectories that involves receiving initial position and velocity data, determining horizontal and vertical motion components, and selecting appropriate motion policies to execute a swing trajectory that maximizes vertical acceleration and velocity within limits, while avoiding obstacles and ensuring timely touchdown, using a combination of horizontal and vertical motion policies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If traditional navigation methods are used for legged robots, then the robot can navigate through environments, but the movement is slow and arduous with frequent collisions and loss of balance
Solution Approach 1:
The patent segments the leg swing trajectory into independent horizontal and vertical motion components. The horizontal component handles position and direction while the vertical component manages height and timing. This segmentation allows each component to be optimized independently - horizontal for speed and direction accuracy, vertical for balance and collision avoidance - resolving the contradiction between navigation speed and balance stability.
2Productivity
If aggressive motion policies are used to maximize speed, then navigation efficiency improves, but the risk of collisions and loss of balance increases
Solution Approach 1:
The patent adds the vertical dimension as a separate control layer from horizontal motion. By independently controlling vertical trajectory (height, timing, acceleration) separate from horizontal position, the system can execute aggressive horizontal motion policies for speed while using vertical control to ensure safe touchdown timing and avoid obstacles, thus improving navigation efficiency without increasing collision risk.
3Device complexity
If the leg swing trajectory is planned as a single coupled motion, then the control is simpler, but the ability to optimize speed and avoid obstacles is reduced
Solution Approach 1:
The patent divides the coupled leg swing trajectory into separate horizontal and vertical motion policies that can be independently selected and optimized. This segmentation increases control complexity but enables significantly faster leg swing speeds by allowing aggressive horizontal policies combined with carefully timed vertical policies, overcoming the speed limitation of coupled control.
Data Source
AI summary
A method of planning a swing trajectory for a leg of a robot includes receiving an initial position of a leg of the robot, an initial velocity of the leg, a touchdown location, and a touchdown target time. The method also includes determining a difference between the initial position and the touchdown location and separating the difference between the initial position and the touchdown location into a horizontal motion component and a vertical motion component. The method also includes selecting a horizontal motion policy and a vertical motion policy to satisfy the motion components. Each policy produces a respective trajectory as a function of the initial position, the initial velocity, the touchdown location, and the touchdown target time. The method also includes executing the selected policies to swing the leg of the robot from the initial position to the touchdown location at the touchdown target time.