Biped Robot Waist Pose Adjustment for Accurate Centroid Control
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Solution Overview
Problem
Conventional biped robot control technology uses a three-mass model to simplify the robot structure, resulting in significant deviations between calculated and planned centroid positions, affecting balance control and quick motion during walking.
Innovation Solution
A computer-implemented method for adjusting the robot centroid position using a linear positive correlation between waist pose changes and centroid position changes, employing the Newton-Raphson iterative method and inverse kinematics algorithms to iteratively refine the centroid position until it matches the planned value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a three-mass model is used to simplify robot structure for centroid calculation, then calculation complexity is reduced, but centroid position accuracy deteriorates with errors of 3-5 centimeters
Solution Approach 1:
The patent implements an iterative feedback mechanism using the Newton-Raphson method. The control system calculates the actual centroid position based on robot pose, compares it with the planned centroid position, and generates feedback to adjust the waist pose. This closed-loop feedback continues until the centroid position error converges to within acceptable tolerance, resolving the contradiction between simplified calculation and high accuracy by iteratively refining the solution.
Solution Approach 2:
The patent dynamically changes the waist pose parameters (position and orientation) based on the calculated centroid position error. By adjusting these parameters iteratively through the Newton-Raphson method, the system transforms the simplified three-mass model calculation into an accurate centroid positioning system, achieving centimeter-level or millimeter-level accuracy without requiring complex full-body dynamics models.
2Measurement precision
If iterative methods like Newton-Raphson are used to improve centroid position accuracy, then centroid position accuracy improves, but computational time increases
Solution Approach 1:
The patent performs preliminary action by pre-calculating and storing the Jacobian matrix of the three-mass model in advance. During real-time control, the system only needs to perform simple matrix operations with pre-computed values rather than calculating complex derivatives iteratively. This preliminary preparation significantly reduces the computational burden of each iteration, enabling high-accuracy centroid positioning to be achieved within real-time control cycles of less than 0.3 milliseconds.
Solution Approach 2:
The patent optimizes the iterative process by changing the calculation parameters - using the Newton-Raphson method with pre-computed Jacobian matrices and setting appropriate convergence criteria. This approach achieves rapid convergence typically within 3-5 iterations, balancing computational accuracy with real-time performance requirements for biped robot control.
3Reliability
If centroid position accuracy is improved through iterative adjustment, then balance control capability improves, but device complexity increases
Solution Approach 1:
The patent makes the waist pose serve multiple functions: it is both the primary actuator for robot motion and the adjustment mechanism for centroid positioning. By coupling centroid correction with waist pose adjustment, the system achieves accurate balance control without requiring separate actuators or complex multi-body dynamics calculations, thus improving reliability while maintaining relatively simple device architecture.
Data Source
AI summary
The present disclosure provides a robot centroid position adjustment method as well as an apparatus and a robot using the same. The method includes: obtaining initial values; obtaining a waist velocity adjustment value; calculating a current value of the centroid position; and determining whether a current value of the centroid position is equal to the planning value of the centroid position; if the current value of the centroid position is not equal to the planning value of the centroid position, obtaining the current value of the centroid position to take as the initial value of the centroid position and returning to the step of obtaining the waist velocity adjustment value until the current value of the centroid position is equal to the planning value of the centroid position. In such a manner, the balance ability of the robot can be improved.