Bipedal Robot Walking Control Using ZMP Safety Area Feedback
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Solution Overview
Problem
Torque-based walking control methods for bipedal robots often result in ineffective balancing motions that cause time delays and energy waste, as they maintain balance through unnecessary foot-stamping actions despite achieving the intended walking task.
Innovation Solution
A robot walking control apparatus and method that unifies torque-based and position-based control methods, using a controller to calculate and adjust joint torques based on the zero moment point (ZMP) to ensure the ZMP remains within a safety area, thereby eliminating unnecessary balancing motions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If torque-based FSM control method is used, then energy efficiency is improved and safety is enhanced through low rigidity, but ineffective balancing motions occur causing time delay and energy waste
Solution Approach 1:
The patent extracts and removes the ineffective balancing motion component from the torque-based control system. By detecting when balancing motion is unnecessary (when ZMP is already within safety area), the system eliminates these redundant foot-stamping actions, thereby removing the time delay and energy waste associated with them while preserving the energy-efficient torque-based control for necessary motions.
Solution Approach 2:
The patent implements feedback by continuously monitoring the ZMP position and comparing it against the safety area boundaries. This feedback mechanism allows the system to dynamically determine when balancing motion is needed versus when it is redundant, enabling the controller to suppress unnecessary balancing motions and achieve both energy efficiency and time optimization.
2Use of energy by moving object
If torque-based FSM control method is used, then energy efficiency is improved, but ineffective balancing motions occur causing energy waste
Solution Approach 1:
The patent extracts and removes the ineffective balancing motion component from the torque-based control system. By detecting when balancing motion is unnecessary (when ZMP is already within safety area), the system eliminates these redundant foot-stamping actions, thereby removing the time delay and energy waste associated with them while preserving the energy-efficient torque-based control for necessary motions.
Solution Approach 2:
The patent implements feedback by continuously monitoring the ZMP position and comparing it against the safety area boundaries. This feedback mechanism allows the system to dynamically determine when balancing motion is needed versus when it is redundant, enabling the controller to suppress unnecessary balancing motions and achieve both energy efficiency and time optimization.
3Adaptability or versatility
If torque-based FSM control method is used, then adaptability to various poses is improved, but unnecessary balancing motions occur due to restricted motion states
Solution Approach 1:
The patent applies dynamics by making the control approach adaptive rather than fixed. The system dynamically switches between two control modes: torque-based FSM control when adaptability to various poses is needed, and position-based control when walking efficiency is the priority. This dynamic selection based on real-time conditions allows the robot to optimize between pose adaptability and walking efficiency.
Solution Approach 2:
The patent changes the control parameter from purely torque-based to a hybrid approach that incorporates position-based control elements. By adjusting the control strategy parameter (torque-based vs. position-based) based on the walking situation, the system eliminates unnecessary balancing motions while maintaining the ability to achieve various poses when required.
Data Source
AI summary
Disclosed are a robot walking control apparatus, which removes an ineffective motion, generated by a robot walking based on torque, by selecting a motion state of the robot based on torque and controlling torques of joints of the robot so that a ZMP of the robot is located in a safety area, when the walking of the robot is controlled, and a method thereof.