Passive Torque Adjustment for Robot Gear Backlash Reduction
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Solution Overview
Problem
Industrial robots face challenges with backlash, which impairs control and precision due to gaps between gear flanks, and existing solutions are either expensive or difficult to retrofit onto existing robots.
Innovation Solution
A passive mechanical torque adjusting device is introduced, comprising a spring or torsion spring mechanism that applies a constant or variable torque to the output member, independent of the actuator gear, allowing for improved torque distribution and reduced backlash without active components, enabling retrofitting on existing robots.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-precision gears are used to reduce backlash, then manufacturing precision is improved, but device complexity and cost increase
Solution Approach 1:
A torque adjusting device is introduced as an intermediary component between the motor and gear unit. This device actively adjusts the torque transmitted to the gear unit, preventing the gear flanks from separating and eliminating backlash without requiring higher gear precision. The torque adjusting device acts as a mediator that compensates for the limitations of standard gear manufacturing.
Solution Approach 2:
The invention changes the torque parameter dynamically by introducing a torque adjusting device that can vary the torque applied to the gear unit. By actively controlling the torque level, the system prevents backlash formation through parameter adjustment rather than relying on fixed high-precision mechanical tolerances.
2Measurement precision
If complex mechanical torque adjusting systems are used to reduce backlash, then positioning accuracy is improved, but device complexity increases
Solution Approach 1:
The invention replaces complex passive mechanical torque adjusting mechanisms with an active control system that uses sensors and a controller. Instead of relying on complicated mechanical arrangements, the system uses electronic control to adjust torque, substituting mechanical complexity with a more manageable control architecture.
Solution Approach 2:
The system incorporates feedback through sensors that detect the actual torque or position, and a controller that adjusts the torque accordingly. This closed-loop feedback mechanism achieves high positioning accuracy without requiring overly complex mechanical structures, as the control system compensates for variations in real-time.
3Manufacturing precision
If existing robots are retrofitted with torque adjusting devices, then accuracy is improved, but ease of operation decreases
Solution Approach 1:
The torque adjusting device is designed as a separate, modular component that can be installed independently of the existing robot structure. This segmentation allows the device to be added as a distinct module without requiring disassembly or modification of the original robot components, maintaining ease of operation during retrofitting.
Solution Approach 2:
The torque adjusting device is designed with universal mounting capabilities that can accommodate different robot models and gear unit configurations. By creating a universal interface and mounting system, the device can be retrofitted onto various existing robots without requiring custom installation procedures for each model, preserving ease of operation.
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 enhances the accuracy and precision of industrial robots by increasing the static torque on the output member, reducing backlash, and can be implemented as a cost-effective and simple addition to existing systems, improving path performance and positioning accuracy.
Implementation Method 1
A passive mechanical torque adjusting device, comprising a spring or torsion spring mechanism that applies a constant or variable torque to the output member
Data Source
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AI summary
Arrangement (40) for an industrial robot (10), the arrangement (40) comprising a rotatable input member (30); a rotatable output member (34) arranged to rotate about a substantially vertical rotational axis (18); a gear unit (32) defining a gear ratio between the input member (30) and the output member (34); and a passive mechanical torque adjusting device (42) configured to apply a torque to the output member (34) around the rotational axis (18) such that the absolute value of a static torque on the output member (34) is increased. An industrial robot (10) comprising the arrangement (40) and a method for controlling backlash in an industrial robot (10) are also provided.