6-DoF Parallel Robotics for Axial Induction-Kinetic Welding
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Solution Overview
Problem
Conventional Induction-Kinetic Welding (IKW) processes rely on two degrees of freedom, which limits their versatility and efficiency in achieving the required kinetic heating for Dynamic Recrystallization (DRX), especially for complex geometries and long workpieces, as they often require transverse shear motions and rigid frame structures, restricting the types of welds that can be made and necessitating the feeding of long workpieces through the machine.
Innovation Solution
The use of 6-DoF parallel robotic systems, which provide precise motion control and generate the necessary kinetic heating through axial motion, allowing for a new spectrum of welding capabilities, including single-axis oscillations, and enabling the use of complex hybrid motions without sacrificing machine stiffness, thus expanding the capabilities of the IKW process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional 2-DoF IKW processes use transverse shear motions and rigid frame structures, then the required kinetic heating for DRX is achieved, but the versatility for complex geometries is limited and long workpieces must be fed through the machine
Solution Approach 1:
The patent transitions from 2-DoF planar motion to 6-DoF spatial motion, adding three rotational degrees of freedom (roll, pitch, yaw) to the existing two translational degrees of freedom. This dimensional expansion enables the welding system to accommodate complex geometries and orientations without requiring workpiece repositioning or specialized fixtures, directly resolving the versatility limitation while maintaining a manageable machine structure through modular parallel robotic architecture
2Measurement precision
If 6-DoF parallel robotic systems are used to provide precise motion control, then positioning accuracy is maintained, but the machine stiffness may be compromised
Solution Approach 1:
The patent employs dynamically adjustable parallel robotic mechanisms where the stiffness characteristics can be actively controlled and optimized during operation. The system uses real-time control algorithms to maintain positional accuracy while adapting structural rigidity based on the specific welding phase and requirements, allowing the machine to exhibit high stiffness when needed for precision positioning and greater flexibility when accommodating complex geometries
Solution Approach 2:
The system utilizes variable parameters including adjustable actuator forces, controllable joint stiffness, and dynamically tuned control gains to optimize the balance between positioning accuracy and machine rigidity. By changing these parameters based on operational conditions, the system maintains high positioning precision without sacrificing overall structural stability
3Force
If conventional IKW processes use rigid frame structures, then the torsional and axial forces are effectively reacted, but the device complexity and weight increase
Solution Approach 1:
The patent replaces traditional heavy rigid mechanical frame structures with parallel robotic mechanisms that use controlled actuator forces to provide structural support and force reaction. The active control system substitutes for passive mechanical rigidity, allowing the machine to react torsional and axial forces through coordinated actuator operation rather than through massive structural components, significantly reducing overall machine weight while maintaining force reaction capability
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 approach enables high-quality welds with non-circular cross-sections, conserves parent metal, and allows for the instantaneous transition between various motion types, enhancing the versatility and efficiency of the IKW process by maintaining high positioning accuracy and delivering the required kinetic energy without the need for additional mechanical complexity.
Implementation Method 1
the IKW process uses non-contact induction heating to raise both surfaces to the hot forging temperature
Implementation Method 2
there is instant bonding and zero sliding behavior. Instead, the interface area immediately goes into viscoplastic flow in response to any lateral motion. Also, the normal force averages near zero during lateral motion and in some instants the normal force is actually negative during the kinetic phase
Data Source
AI summary
With the present invention, the combination of amplitudes and velocities of rotary and axial motions required for an Induction-Kinetic Welding (IKW) process are achieved with Stewart Platforms, also known as parallel actuators, which typically have 6-DoF. The 6-DoF systems are used to generate the kinetic heating essential to the IKW process. Another new welding process uses only axial (longitudinal) motion, in contrast to prior systems which rely upon some form of transverse shear motion. The present invention takes advantage of this new single axis IKW discovery in combination with the 6-DoF discovery to enable an entirely new spectrum of welding capabilities for the IKW process. In an embodiment the system includes a claim shell type apparatus allowing for opening and closing the welding system around the components to be welded.