Underactuated Joining Mechanism for Moving Workpiece Tracking
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Automated manufacturing tasks face challenges in efficiently performing joining operations on moving workpieces, as existing systems struggle to accurately synchronize the motion of rigid bodies in motion, leading to potential impingement and damage during the joining process.
Innovation Solution
An underactuated joining system is introduced, comprising a robot with actively-controlled joints and a passive articulated compliance mechanism, which uses position sensors and a controller to adjust the robot's position and maintain compliance, allowing the joining tool to follow the workpiece in a non-rigid manner, enabling accurate tracking and engagement even with human operator interaction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rigid robot system is used for joining operations on moving workpieces, then positioning precision can be maintained, but relative motion errors occur between the robot and workpiece leading to impingement and damage
Solution Approach 1:
The patent applies dynamics by transitioning from a rigid robot system to a compliant robot system that can dynamically adapt its position and orientation. The compliant robot incorporates flexible elements and passive joints that allow real-time motion adjustment to match the workpiece movement, eliminating relative motion errors and preventing impingement during joining operations.
Solution Approach 2:
The patent changes the rigidity parameter of the robot system by introducing compliance mechanisms. The compliant robot system modifies its mechanical properties to allow controlled flexibility, enabling it to absorb and adapt to workpiece motion variations without causing damaging relative movements during the joining process.
2Object-affected harmful factors
If a compliant mechanism is introduced to allow following motion, then relative motion errors are prevented, but system complexity increases due to additional sensors and control mechanisms
Solution Approach 1:
The patent applies self-service through passive compliance mechanisms that automatically adapt to workpiece motion without requiring complex active control. The compliant robot system uses inherent mechanical compliance and simple position sensors to self-adjust its configuration, eliminating the need for complex real-time control algorithms while still preventing relative motion errors.
Solution Approach 2:
The patent introduces simple position sensors as intermediaries between the compliant mechanism and the control system. These sensors provide minimal feedback about the compliant joint positions, enabling the controller to maintain accuracy without requiring complex sensing systems, thus balancing compliance with system simplicity.
3Productivity
If traditional automated joining systems are used, then manufacturing throughput can be maintained, but operator task loads remain high requiring extensive manual support
Solution Approach 1:
The patent applies universality by creating a compliant robot system that can perform multiple functions: it maintains automated joining operations for high throughput while simultaneously adapting to manual operator guidance when needed. The system's compliance allows it to serve both automated and collaborative modes, reducing operator task loads across different operational scenarios.
4Manufacturing precision
If active control is used to track workpiece motion, then joining accuracy is maintained, but the system becomes less adaptable to human operator interaction
Solution Approach 1:
The patent applies dynamics by using passive compliance mechanisms that naturally adapt to external forces applied by human operators. When an operator manually guides the end effector, the compliant joints passively follow the applied motion while position sensors detect the displacement, allowing the system to maintain joining accuracy regardless of whether the motion comes from automated control or human interaction.
Data Source
AI summary
An underactuated joining system for a moving assembly line includes a robot with actuated joints, an articulated compliance mechanism, and a controller. An end-effector of the mechanism is connected to linkages and to a joining tool, unactuated joints interconnect the linkages, and position sensors measure joint positions of the unactuated joints. In response to the joint positions, a controller regulates a position of the actuated joints to cause the compliance mechanism to compliantly follow the assembly line. This occurs while the tool remains engaged with a workpiece being transported along the assembly line. A method includes engaging the tool with the workpiece as the workpiece is transported by the assembly line, measuring joint positions of the unactuated joints using position sensors, and controlling a position of the active joints to cause the compliance mechanism to compliantly follow the workpiece along the assembly line.