Industrial Robot Virtual Surface Programming for Force Control
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Solution Overview
Problem
Existing methods for programming industrial robots do not effectively allow operators to program the robots to exhibit predetermined force and/or moment behavior during user program execution.
Innovation Solution
A method involving manual guidance of the robot to a virtual surface in space, where the robot is actuated to stop further manual guidance, and the force and/or torque are determined and stored, allowing for programming of force and/or torque behavior for automatic operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the playback method is used to program the industrial robot by manually guiding it along a desired curve, then the motion path can be programmed relatively simply, but the robot cannot exhibit predetermined force and/or moment behavior during execution
Solution Approach 1:
The patent creates a virtual surface model that copies the essential geometric and force characteristics of the actual workpiece surface. During manual guidance, the system measures forces and torques against this virtual model, storing them for later playback. This allows the robot to reproduce both position and force behavior without requiring physical contact with the actual workpiece during programming, thus maintaining programming simplicity while adding force control capability.
Solution Approach 2:
The virtual surface acts as an intermediary between the operator and the actual workpiece. Instead of directly interacting with the physical workpiece to program force characteristics, the operator interacts with the virtual surface model. This intermediary enables force measurement and storage during manual guidance while preventing actual contact with the workpiece, bridging the gap between simple manual programming and precise force control.
2Manufacturing precision
If the robot is programmed to apply predetermined forces and torques during operation, then precise control is achieved, but the programming process becomes more complex
Solution Approach 1:
The system performs preliminary measurement and storage of force and torque characteristics during the manual guidance phase. By pre-measuring the forces required to follow the virtual surface and storing them in advance, the complex force control calculations are completed during programming rather than during execution. This preliminary action simplifies the actual operation phase while achieving precise force control.
Solution Approach 2:
The virtual surface model copies the force-field characteristics of the actual workpiece environment. By creating this virtual replica during programming, the system captures all necessary force and torque information in advance. During automatic execution, the robot simply follows the pre-recorded force profile from the virtual surface model, avoiding complex real-time force calculations and reducing operational complexity.
3Measurement precision
If manual guidance is allowed beyond the virtual surface, then force measurement can be performed, but the robot position becomes uncontrolled
Solution Approach 1:
The control system dynamically adjusts its behavior based on the robot's position relative to the virtual surface. When the robot is exactly on the virtual surface, normal position control is active. When the robot attempts to penetrate the virtual surface, the system switches to force measurement mode, where the virtual surface constraint is temporarily relaxed to allow penetration for measurement purposes, but the position is immediately restored afterward. This dynamic switching enables both accurate force measurement and position control reliability.
Solution Approach 2:
The virtual surface acts as a preliminary constraint that prevents unauthorized position deviations. When force measurement is required, the system temporarily suspends this constraint to allow controlled penetration, measures the forces, then immediately re-establishes the constraint to restore position control. This preliminary anti-action (the virtual surface barrier) is strategically removed only when needed for measurement, ensuring both measurement accuracy and position control reliability.
Data Source
AI summary
The invention relates to an industrial robot and a method for programming an industrial robot, for which the industrial robot is guided manually to a virtual surface (25) in the room, at which point the industrial robot is selected such that it cannot be guided any further manually. Next, that force (F) and/or torque acting on the industrial robot when an attempt is made to guide the industrial robot further manually is ascertained and stored, despite reaching the virtual surface (25).