Robot Finger Joint With Load-Engaging Spring Mechanism
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Solution Overview
Problem
Conventional hand devices attached to robot arms struggle to maintain posture and operation state when subjected to large loads exceeding the normal use range, leading to unintentional movement and potential breakage.
Innovation Solution
A joint structure comprising a base, a movable link, an elastic member, and an engagement mechanism that biases the link to maintain positions and engages with the base when excessive loads are applied, ensuring the load is received by the base rather than the movable link, thereby maintaining the operation state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If only a drive force of an actuator and a biasing force of an elastic member are used to maintain the operation state, then the device complexity is reduced, but the reliability deteriorates when large loads exceeding normal use range are applied
Solution Approach 1:
The joint structure employs a dynamic engagement mechanism that transitions between engaged and disengaged states based on load conditions. The engagement mechanism includes engagement protrusions and recesses that automatically engage when excessive load is detected, transforming the static support system into a dynamic one that adapts to varying load conditions, thereby improving reliability without permanently increasing structural complexity
Solution Approach 2:
The engagement mechanism is pre-configured with engagement protrusions and recesses positioned to automatically engage when excessive load occurs. This preliminary arrangement ensures that the load transfer path is ready in advance, allowing the base to immediately support excessive load without requiring active control or complex sensing systems
2Stability of the object's composition
If a brake mechanism is used to fix the position of the link, then the stability is improved, but the device complexity increases
Solution Approach 1:
The invention extracts the position-fixing function from a complex brake mechanism and implements it through a simple engagement mechanism with protrusions and recesses. This engagement mechanism is integrated into the existing joint structure, eliminating the need for separate brake components while maintaining position stability through mechanical engagement rather than friction-based braking
3Reliability
If the elastic member biasing force is increased to handle large loads, then the reliability is improved, but the ease of operation deteriorates due to excessive biasing force during normal operation
Solution Approach 1:
The engagement mechanism dynamically switches the load-bearing path between the elastic member alone (normal operation) and the elastic member plus engagement mechanism (excessive load). This dynamic switching allows the elastic member to operate at optimal biasing force for normal operation while the engagement mechanism provides additional support only when needed, preventing excessive biasing force during normal use
Solution Approach 2:
The load support function is segmented into two stages: normal load supported by the elastic member alone, and excessive load supported by the combined elastic member and engagement mechanism. This segmentation allows the elastic member to be optimized for normal operation while the engagement mechanism handles peak loads, avoiding the need to oversize the elastic member for maximum load conditions
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 solution effectively allows the robot to maintain its operation state and posture even under large loads, preventing breakage and unintended movement by distributing the load to the base, thus enhancing the robot's stability and functionality.
Implementation Method 1
an elastic member that biases the second link member in a direction opposite to a direction in which a load is applied to the second link member from the object so that a position of the second link member with respect to the first link member is maintained at a predetermined position
Data Source
AI summary
A second finger 40c of a hand part 40 includes a first link member 40c1 and a second link member 40c2 that are integrally rotatable with respect to a hand base 40a, a spring 40c3, and a second finger side engagement part 40c4. The spring 40c3 biases the second link member 40c2 so that a position of the second link member 40c2 with respect to the first link member 40c1 is maintained. A second finger side engagement part 40c4 is engaged with a hand base side engagement part 40a1 when the second link member 40c2 is moved by a load applied from an object O against a biasing force of the spring 40c3.