Machine Tool Support Device Force Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Machine tools face challenges in maintaining machining precision due to workpiece deflection, which is often exacerbated by the need for high rigidity in support devices to prevent deflection, leading to increased size and cost.
Innovation Solution
A machine tool design that employs a support device with low rigidity, controlled through force control, using a multi-degrees-of-freedom robot with an end effector that measures and adjusts supporting and machining forces to balance them, thereby stabilizing the workpiece without requiring high rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If position control is used to precisely position the support point, then machining precision is improved, but the rigidity of the support device must be increased, leading to increased size and cost
Solution Approach 1:
The invention changes the control parameter from position to force. Instead of controlling the support device to maintain a specific position, the system controls the support device to apply a specific force to the workpiece. This allows the use of low-rigidity support devices (such as robots) while still achieving precise workpiece support through force feedback control that adjusts for positioning errors and device deflection.
2Measurement precision
If the rigidity of the support device is increased to reduce control error, then positioning precision is improved, but the size and cost of the support device increase
Solution Approach 1:
The invention changes the control parameter from position to force. Instead of controlling the support device to maintain a specific position, the system controls the support device to apply a specific force to the workpiece. This allows the use of low-rigidity support devices (such as robots) while still achieving precise workpiece support through force feedback control that adjusts for positioning errors and device deflection.
Data Source
AI summary
A machine tool which removal-machines a workpiece by means of a tool includes a retaining device (a workpiece spindle and a tailstock) that retains the workpiece, a support device (an in-machine robot) that supports the workpiece, in order to suppress deflection of the workpiece retained by the retaining device, and a control device that controls driving of the support device by force control having a force as a control target. Specifically, a supporting force by the support device and a machining force by a tool are measured, and the driving of the support device is controlled so that the supporting force is equal to the machining force.