Wheel-Legged Robot Balance Control Across Changing Motion States

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Solution Overview

Problem

Existing balance control methods for wheel-legged robots are limited in applicability and lack robustness across different motion states, necessitating improvements in stability and adaptability.

Innovation Solution

The wheel-legged robot is simplified into an n-th order inverted pendulum model, allowing for the calculation of equivalent state parameters and the use of a sliding surface to determine force and torque instructions for whole-body joints, enabling separate control of revolute joints to adjust balance status.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the leg mechanism and torso mechanism are considered as a whole to calculate rotation torque for balance control, then the balancing capability during movement is improved, but the control method becomes applicable only to a few scenarios and lacks robustness across different motion states

Engineering Contradiction:
Improvebalancing capabilityVSAvoidapplicability across motion states
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent segments the balance control problem by separately controlling the mobile wheel mechanism and the leg mechanism through independent torque calculations. The mobile wheel mechanism has its own balance control torque calculated based on its state parameters, while the leg mechanism has separate torque control. This segmentation allows each mechanism to be optimized for its specific motion characteristics, improving both reliability and adaptability across different motion states.

Inventive Principle:
Principle #1Segmentation

2Measurement precision

If a specific balance control method is designed for particular motion scenarios, then the control precision for those scenarios is improved, but the controller cannot be universally applied when motion modes are switched

Engineering Contradiction:
Improvecontrol precisionVSAvoidcontroller universality
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent creates a universal balance control method that works across multiple motion modes by establishing a unified control framework. The control system can adapt to different motion states (wheeled motion, legged motion, transition phases) using the same fundamental control architecture. The state parameters and torque calculations are designed to be applicable regardless of the current motion mode, allowing the controller to maintain precision while being universally applicable.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4650887A1Balance control method and apparatus for wheel-legged robot, device, and storage medium
Publication Date: 2025.11.19 TENCENT TECHNOLOGY (SHENZHEN) CO LTD
  • EP4650887A1 patent drawingFigure 1~2
  • EP4650887A1 patent drawingFigure 3~4
  • EP4650887A1 patent drawingFigure 5~7

AI summary

A balance control method and apparatus (1600) for a wheel-legged robot (200), a device, and a storage medium. The method is executed by a computer device (101). An n-order inverted pendulum model as which the wheel-legged robot (200) is equivalently represented comprises: wheels (1016), n connecting rods and n rotating joints; first connecting rods (1026, 1110) are equivalently derived from at least two leg mechanisms (1022, 1024) of the wheel-legged robot (200), and the wheels (1016) are equivalently derived from moving wheels (1012, 1014) respectively connected to the at least two leg mechanisms (1022, 1024). The method comprises: step 1310, acquiring an actual state quantity of the wheel-legged robot (200) at a first moment; step 1320, calculating an equivalent state quantity at the first moment on the basis of the actual state quantity at the first moment; step 1330, establishing a sliding mode surface on the basis of the equivalent state quantity at the first moment; step 1340, determining a force and torque instruction of the whole body joint on the basis of a dynamic equation of the sliding mode surface and the equivalent state quantity at the first moment; and step 1350, at a second moment, respectively controlling the n rotating joints on the basis of the force and torque instruction. The method is adapted to a wheel-legged robot (200) in movement, facilitating improvement of the robustness of balance control.