Robot Arm Spring-Damper Control for External Force Absorption
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Solution Overview
Problem
Traditional robot arms are rigid and can cause harm or damage due to high forces when moving at high speeds, lacking the ability to intelligently react to externally applied forces.
Innovation Solution
A robot arm design incorporating a spring-damper element and a control unit that combines passive and active yielding capacities, allowing the arm to respond to external forces with adjustable force-displacement characteristics, and can absorb rapid forces while minimizing resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional rigid robot arms are used, then structural strength and positioning precision are improved, but safety and ability to respond to external forces deteriorate
Solution Approach 1:
The patent changes the mechanical parameter of the robot arm from rigid to compliant by introducing spring-damper elements. This allows the arm to maintain structural integrity while being able to yield to external forces, thereby preventing harm. The spring constant and damping coefficient are adjusted to achieve the desired balance between strength and safety.
Solution Approach 2:
The robot arm employs a composite structure combining rigid components (for maintaining shape and positioning) with compliant components (spring-damper elements for safety). This composite design allows different parts of the system to have different mechanical properties, achieving both structural strength and harm prevention simultaneously.
2Productivity
If rigid robot arms move at high speeds, then productivity is improved, but safety and controlability deteriorate due to inability to react to external forces
Solution Approach 1:
The spring-damper elements are pre-installed in the robot arm to provide cushioning before any collision or external force application occurs. When high-speed movement is interrupted by an external force, these elements immediately absorb the impact energy, preventing damage. The damper component specifically addresses rapid force applications by dissipating energy through viscous damping.
3Object-affected harmful factors
If spring-damper elements are added to provide yielding capacity, then safety is improved, but device complexity increases
Solution Approach 1:
The patent merges the spring and damper elements into a single integrated mechanical coupling component between arm segments. This combined element provides both elastic compliance (spring) and viscous damping (damper) in one unit, reducing the number of separate components and simplifying the overall mechanical structure while maintaining safety functions.
4Manufacturing precision
If control unit compensates for disturbing forces, then positioning precision is improved, but energy consumption increases during rapid force absorption
Solution Approach 1:
The spring-damper elements act as intermediary components between the motor and the external environment. When rapid external forces are applied, these intermediaries absorb the shock loads mechanically, preventing them from being transmitted to the motor. This allows the motor to maintain precise positioning control without expending excessive energy counteracting rapid force variations.
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 robot arm effectively absorbs external forces, ensuring safety by providing a yielding capacity that prevents damage and harm, while maintaining control and precision in interacting with humans or objects.
Implementation Method 1
a spring-damper element that is configured to dampen a movement of the first arm segment in relation to the second arm segment
Implementation Method 2
a spring-damper element that is configured to dampen a movement of the first arm segment in relation to the second arm segment
Data Source
AI summary
A robot includes a yielding element for mechanically coupling first and second arm segments of a robot arm. A motor moves the second arm segment relative to the first arm segment. A sensor determines a relative position of the first arm segment in relation to the second arm segment and outputs a position sensor signal representing the relative position. A control unit controls the motor in accordance with the position sensor signal such that the first arm segment is moved into a desired relative position in relation to the second arm segment, when no external force is applied to the robot arm, and when an external force is applied to the robot arm, the motor generates a counterforce which depends on the deviation between the actual and desired positions. The control unit has a predetermined time constant so that changes in the external force are substantially absorbed by damping elements.