Torque-Based Walking Robot Control for High Rigidity and Stability
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Solution Overview
Problem
Existing torque-based control methods for walking robots suffer from low rigidity and energy inefficiency, and switching between position-based and torque-based control methods can cause unstable control and hardware damage due to current and voltage spikes.
Innovation Solution
A control method that measures and calculates target torques using torque sensors, adjusts the torque range, and applies a specific voltage to actuators using proportional, integral, and differential gain control to maintain high rigidity within a single torque-based control method, preventing the need for method switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If position-based ZMP control method is used, then precise position control and high rigidity are achieved, but high current consumption and low energy efficiency occur
Solution Approach 1:
The patent changes the control parameter from position-based to torque-based control. By controlling joint torques instead of positions, the system achieves high rigidity through torque feedback while allowing more natural motion patterns that consume less energy, resolving the contradiction between rigidity and energy efficiency
Solution Approach 2:
The patent replaces the position-based mechanical control system with a torque-based control system. This substitution allows the robot to maintain rigidity through active torque control while enabling more energy-efficient natural gaits that avoid the high currents required for precise position tracking
2Adaptability or versatility
If switching between position-based ZMP control and torque-based FSM control is performed, then control flexibility is improved, but current and voltage spikes occur causing unstable control and potential hardware damage
Solution Approach 1:
The patent merges the advantages of both position-based and torque-based control methods into a unified torque-based control system. By integrating ZMP constraint satisfaction with FSM state transitions through torque control, the system maintains control flexibility while eliminating switching-induced current and voltage spikes that cause instability
Solution Approach 2:
The patent creates a universal torque-based control framework that can handle multiple control objectives (ZMP constraints, FSM state transitions, trajectory tracking) within a single control methodology, eliminating the need to switch between different control methods and their associated stability issues
3Use of energy by moving object
If torque-based FSM control method is used, then energy efficiency and natural gait are achieved, but low rigidity occurs
Solution Approach 1:
The patent implements torque feedback control where the actual joint torques are measured and compared with target torques. This feedback mechanism enables the system to maintain high rigidity by actively correcting torque deviations while preserving the energy efficiency and natural gait characteristics of torque-based control
Data Source
AI summary
A torque-based walking robot and a control method thereof which stably controls walking of the robot. In the control method, in which high rigidity, equal to that achieved through a position-based control method, is achieved using a torque-based control method without switching between the position-based control method and the torque-based control method while the robot is in motion, a difference between a target torque and a measured torque is forcibly generated by limiting a torque range measurable by each torque sensor, thereby increasing voltage applied to each actuator, and thus achieving high rigidity, equal to that achieved through the position-based control method, using the torque-based control method without switching between the position-based control method and the torque-based control method.