H∞ Balance Controller With State Feedback for Mobile Robots
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Solution Overview
Problem
Mobile robots with unstable equilibrium states face challenges in maintaining balance while moving, especially on varying floor conditions and uneven surfaces, leading to instability and difficulty in system identification.
Innovation Solution
A stable balance controller is implemented, comprising an H∞ controller and a state-feedback circuit with nested feedback loops, which generates control effort signals to manage tracking errors and improve robustness against floor conditions, enabling agile maneuvers and self-balancing capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a mobile robot with unstable equilibrium state is used for navigation among pedestrians, then the robot's responsiveness and predictability improve, but the robot's stability and ease of control deteriorate
Solution Approach 1:
The patent implements a state feedback control mechanism where the controller continuously monitors the robot's state (position, velocity, acceleration) and adjusts the control input based on the difference between the actual state and desired state. This feedback loop enables the unstable robot to maintain controllability while preserving its natural dynamic responsiveness, resolving the contradiction between responsiveness and stability.
Solution Approach 2:
The patent employs dynamic parameter adjustment in the control system, where control gains and damping coefficients are modified based on the robot's operating conditions and state. This allows the controller to adapt the level of stabilization applied, maintaining responsiveness during normal operation while providing enhanced stability when needed, thus resolving the contradiction between these two parameters.
2Reliability
If an H∞ controller with state-feedback circuit is implemented for balance control, then the robot's robustness against varying floor conditions improves, but the device complexity increases
Solution Approach 1:
The patent implements a nested control structure where the state-feedback circuit is integrated within the H∞ control framework. The state feedback provides inner-loop stabilization while the H∞ controller provides outer-loop robustness against disturbances and model uncertainties. This nested arrangement achieves high robustness while organizing the complexity in a structured, manageable way, resolving the contradiction between reliability and device complexity.
3Measurement precision
If feedback loops are used to transfer output signals back to input, then the control precision and balance improvement, but the system complexity and difficulty of system identification increase
Solution Approach 1:
The patent divides the control system into distinct functional modules: the H∞ controller module, the state-feedback circuit module, and the feedback loop module. Each module has a specific function and can be analyzed independently to some extent. This segmentation reduces the overall system complexity by breaking down the complex feedback system into manageable components, while still achieving high control precision through their coordinated operation.
Data Source
AI summary
According to one aspect, a control system for providing stable balance control may include an H∞ controller, a state-feedback circuit, a first feedback loop, and a second feedback loop. The control system may be implemented in a robot as a controller for the robot. The H∞ controller may receive an input signal and generate a control effort signal. The state-feedback circuit may receive the control effort signal as an input and generate an output signal. The feedback loop may include the H∞ controller and the state-feedback circuit and may transfer the output signal of the state-feedback circuit back to the input of the H∞ controller and input a tracking error input signal to the H∞ controller. The tracking error input signal may be the difference between the output signal of the state-feedback circuit and the input signal.