Composite Joint Counterbalance Using Single-Force Distribution
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Solution Overview
Problem
Existing counterbalance systems for robotic joints, particularly those involving revolute and composite joints, face challenges such as increased weight, size, and operational inconvenience due to the use of active counterbalance approaches requiring energy and high-precision components, and passive counterbalance approaches necessitating counterweights and high-density metals, which also fail to adapt to changes in gravity or center of gravity.
Innovation Solution
A counterbalance device and system that utilizes a single force output mechanism to simultaneously counterbalance forces on both translatable and rotatable members of composite joints, employing a pulling mechanism connected to a frame and rotating arm, allowing for constant output force without constraining operational range, and incorporating elastic components and flexible transmission members for adjustable force distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If active counterbalance approaches are used with high-precision sensors and motors, then counterbalance precision is improved, but system weight and complexity increase
Solution Approach 1:
The patent replaces active mechanical counterbalance systems (motors, sensors, controllers) with a passive mechanical counterbalance mechanism using springs and linkages. The spring-based force generation mechanism provides counterbalance force without requiring continuous energy supply or high-precision sensors, thereby reducing system weight and complexity while maintaining adequate counterbalance performance.
Solution Approach 2:
The patent extracts and removes the heavy active components (motors, sensors, power supply systems) from the counterbalance mechanism, retaining only the essential passive mechanical elements (springs, linkages, levers) needed to provide counterbalance force. This extraction significantly reduces system weight and complexity.
2Force
If passive counterbalance approaches with counterweights and high-density metals are used, then counterbalance force is improved, but system volume and weight increase
Solution Approach 1:
The patent changes the physical parameters of the counterbalance system by using springs with adjustable stiffness coefficients instead of fixed-mass counterweights. This allows the counterbalance force to be adjusted by changing spring parameters rather than using heavy metals, achieving the required counterbalance force with significantly reduced system weight.
Solution Approach 2:
The patent introduces dynamic adjustment capabilities through adjustable spring mechanisms and reconfigurable linkages, allowing the counterbalance force to be adapted to different load conditions without requiring heavy fixed counterweights. This dynamic approach provides flexibility while maintaining light system weight.
3Device complexity
If passive counterbalance approaches with fixed counterweights are used, then system simplicity is improved, but adaptability to changes in gravity or center of gravity deteriorates
Solution Approach 1:
The patent makes the counterbalance system dynamic and adjustable by incorporating springs with variable stiffness and reconfigurable linkages. These elements can be adjusted to adapt to changes in gravity or center of gravity of the robotic arm, providing versatility while maintaining relative system simplicity compared to active control systems.
Solution Approach 2:
The patent designs the spring-based counterbalance mechanism to serve multiple functions: providing counterbalance force, allowing adjustment for different gravity conditions, and adapting to different center of gravity positions. This multi-functionality achieves adaptability without significantly increasing system complexity.
4Adaptability or versatility
If active counterbalance systems are used, then adaptability to operational conditions is improved, but energy consumption increases
Solution Approach 1:
The patent employs a self-service passive mechanical counterbalance system where springs automatically provide the necessary counterbalance force based on the robotic arm's position and load conditions. The system adapts to operational conditions through its mechanical design without requiring external energy supply, achieving adaptability while eliminating continuous energy consumption.
Solution Approach 2:
The spring-based system naturally provides periodic counterbalance force as the robotic arm moves through its range of motion, with the spring energy storage and release cycles matching the operational rhythm of the arm. This periodic action provides adaptability without continuous energy input.
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
The system reduces system weight and volume, enhances design flexibility, and maintains smooth operation by adapting to changes in gravity, without the need for continuous energy supply or high-precision sensors, while achieving neutral equilibrium.
Implementation Method 1
incorporating elastic components and flexible transmission members for adjustable force distribution
Data Source
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Figure 3A
AI summary
A counterbalance device for an apparatus with composite joints is provided. The apparatus includes a frame, a first movable member supported by the frame, and a second movable member connected to the first movable member. The first movable member is translatable relative to the frame along a first line, and the second movable member is rotatable relative to the first movable member about a first axis perpendicular to the first line and travers to the direction of the force. The counterbalance device includes: a force output mechanism connected to the frame and configured to provide an output force; a distribution mechanism connected to the force output mechanism, to allow the force output mechanism to apply the output force to the distribution mechanism at a first load-bearing position of the distribution mechanism; and a pulling mechanism connected to the distribution mechanism, to allow the pulling mechanism to act on the distribution mechanism at a second load-bearing position of the distribution mechanism, the pulling mechanism being connected to the first movable member and translatable relative to the first movable member along the first line, the pulling mechanism being further connected to the second movable member, and the pulling mechanism being translatable along the first line with rotation of the second movable member about the first axis.