Liquid Counterweight Control for Robot Balance on Uneven Terrain
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Solution Overview
Problem
Current robotic systems face challenges in maintaining dynamic balance and stability, especially on uneven terrain, due to the complexity and limitations of existing counterbalancing methods, which restrict their ability to operate in hazardous environments and limit their functionality in tasks such as rescue operations and industrial applications.
Innovation Solution
The use of a liquid counterweight system that allows for the dynamic control of a robot's center of mass by redistributing liquid between chambers, enabling the robot to maintain balance and stability on uneven terrain, ascend steep barriers, and self-right after a fall, without the need for complex mechanical structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If mechanical counterbalancing methods are used, then the robot can maintain balance on uneven terrain, but the device complexity and structural constraints increase
Solution Approach 1:
The patent employs a hydraulic counterbalancing system where a piston-cylinder arrangement uses fluid pressure to generate counterbalancing forces. The hydraulic actuator (cylinder 20 with piston 21) replaces complex mechanical linkages, providing smooth and adjustable counterbalancing forces through fluid pressure control, thereby reducing mechanical complexity while maintaining balance reliability
Solution Approach 2:
The system dynamically adjusts the counterbalancing force by varying hydraulic pressure parameters. The counterbalancing subsystem can modify the magnitude and direction of counterbalancing forces through pressure control, allowing adaptation to different terrain conditions and robot configurations without requiring complex mechanical reconfiguration
2Reliability
If permanently-low positioning of Center of Mass is used, then stability is improved, but the robot's ability to overcome barriers is limited
Solution Approach 1:
The patent implements a dynamic counterbalancing system that can adjust the Center of Mass position in real-time based on terrain conditions. The hydraulic actuator moves the counterweight (element 10) to different positions, allowing the robot to optimize its Center of Mass location for either stability on flat ground or for overcoming barriers, thus providing adaptability while maintaining stability when needed
Solution Approach 2:
The system performs preliminary positioning of the counterweight to prepare for upcoming terrain challenges. By anticipating barrier encounters and pre-adjusting the Center of Mass position, the robot optimizes its configuration for barrier overcoming before the actual event, enhancing versatility without compromising stability during normal operation
3Adaptability or versatility
If fluid-driven mechanisms are used, then barrier overcoming capability is improved, but friction and torque drag effects increase
Solution Approach 1:
The patent uses a hydraulic actuator system to move the counterweight, replacing friction-prone mechanical bearings and joints. The fluid-driven piston-cylinder mechanism eliminates sliding contacts and rotating bearings in the counterbalancing subsystem, thereby significantly reducing friction and torque drag effects while maintaining the capability to overcome barriers through controlled fluid pressure
4Reliability
If complex counterbalancing systems are used, then dynamic balance is improved, but the mathematical model and control complexity increase
Solution Approach 1:
The hydraulic counterbalancing system provides inherently smooth and continuous force adjustment, simplifying the control algorithm compared to discrete mechanical systems. The fluid pressure can be modulated continuously to match the robot's dynamic requirements, reducing the complexity of the control mathematics while maintaining high dynamic balance performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution simplifies the mathematical model and control of robotic dynamics, reduces the risk of falling, and allows robots to operate safely and effectively on challenging terrains, including ruins and mountains, while avoiding heavy structural components and minimizing vibrations.
Implementation Method 1
The robot includes a liquid counterweight, at least one pump, and at least two independently moving parts of the body, each comprises at least one liquid chamber
Implementation Method 2
said liquid counterweight being transported and alternatively redistributed between said liquid chambers amassing a major portion of said liquid counterweight at least in one of said at least two liquid chambers
Data Source
AI summary
Dynamic control of a center of mass position is based on replacement of discrete motion of macro body (counterweighing solid or counterbalancing mechanisms) for continuous molecular flow of counterweighing liquid. Redistributing liquid counterweight between chambers attached to independently moving parts of robot allows its motion to new stable position without disruption in static stability and dynamic balance. Various embodiments include bipods/humanoids, wheeled locomotion robots and hybrid wheeled/multi-pod bio-like robotic systems; some embodiments allow reversible mutual reconfiguration between various structural arrangements. In humanoid embodiments, method allows moving on uneven terrain or ascending staircases while maintaining static stability; method also decreases the probability of fall and secures self-rising if a fall occurred. In some embodiments liquid counterweight may be transferred upon high barriers exceeding the height of robot by a few folds, such as walls of the building or ledge or steep slope in mountains, thus providing robots with capability principally not available to prior art.