Robot Path Learning via Force Control Guiding Points
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for programming robot motions, such as lead-through teaching, are time-consuming and burdensome for operators, requiring them to accurately guide robots in three dimensions while avoiding collisions and excessive pressure, especially when dealing with complex workpieces.
Innovation Solution
A method that allows operators to teach a robot the gross spatial relationship between the robot and workpiece using guiding points, then uses force control to update these points and generate a program for the robot to follow, enabling the robot to learn intermediate points and maintain contact with the workpiece without operator guidance in three dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lead-through teaching is used to program robot motions, then the robot can perform complex tasks with accurate path following, but the programming process becomes time-consuming and burdensome for operators
Solution Approach 1:
The teaching process is segmented into two phases: first teaching only gross spatial relationship (guiding points) without requiring continuous operator guidance, then using force control to automatically learn intermediate points along the path. This segmentation reduces the time the operator must actively guide the robot while maintaining path accuracy.
Solution Approach 2:
The robot system performs self-learning of intermediate path points through force control after the operator teaches the guiding points. The robot autonomously explores and records intermediate positions by detecting contact forces with the workpiece, eliminating the need for continuous operator intervention and significantly reducing programming time.
2Manufacturing precision
If the operator guides the robot through desired motions in three dimensions, then accurate path programming is achieved, but the operator must constantly maintain control while avoiding collisions and excessive pressure
Solution Approach 1:
The requirement for continuous operator guidance in three dimensions is extracted and removed from the teaching process. Only the essential gross spatial relationship (guiding points) needs operator input, while the complex task of maintaining continuous control and avoiding collisions is transferred to the force control system.
Solution Approach 2:
Force control acts as an intermediary between the operator's simple guiding point inputs and the robot's complex motion execution. The force control system automatically adjusts the robot's path to maintain proper contact with the workpiece, eliminating the need for the operator to manually manage three-dimensional control and collision avoidance.
3Manufacturing precision
If conventional lead-through teaching is used, then the robot can be programmed to follow complex contours, but the workpiece or tool can be damaged due to operator inability to overcome inertial forces
Solution Approach 1:
The robot performs self-correction of its motion path through force control after the operator teaches the guiding points. The force control system automatically detects contact forces and adjusts the robot's position to follow the correct contour, eliminating the need for the operator to manually overcome inertial forces and preventing workpiece damage.
Solution Approach 2:
Force control provides continuous feedback during the teaching process, allowing the robot to automatically adjust its motion based on contact forces with the workpiece. This feedback mechanism prevents excessive pressure and collisions by real-time force monitoring and path adjustment, eliminating the workpiece damage risk associated with operator manual control.
4Ease of operation
If teaching handles are used to improve mechanical advantage, then the operator can better control the robot, but the operator is still left to manipulate and accurately control the robot through desired motions in three dimensions
Solution Approach 1:
The complex three-dimensional control task is extracted from the operator's responsibilities. Teaching handles provide mechanical advantage for the simplified task of positioning guiding points, while the automated force control system handles the time-consuming continuous three-dimensional manipulation, significantly reducing programming time.
Solution Approach 2:
Force control serves as an intermediary that transforms the operator's simple guiding point inputs (assisted by teaching handles) into complete, accurate motion programs. This intermediary system automatically generates the detailed three-dimensional control paths, eliminating the need for the operator to perform time-consuming manual manipulation.
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 reduces programming time and effort, ensures accurate path following, and prevents collisions, making it feasible for frequent programming of robots in small batch jobs by automating the teaching of complex motion paths.
Implementation Method 1
using a signal from a force sensor on the robot to determine when the robot is holding the tool and moves to follow the path including the plurality of guiding points, if the tool is in contact with the workpiece contour
Data Source
AI summary
A robot having a force sensor and a tool fixture for operating on a workpiece that may have a complex surface contour is programmed by an operator first teaching the robot by a suitable technique such as lead through teaching a few gross points of the contour. These points, known as guiding points, are used to generate a program to be followed by the robot under the control of the robot controller and using force control during which the robot finalizes the guiding points and teaches one or more points on the contour intermediate adjacent guiding points. The controller or other computing device uses the points so taught to generate the path the robot tool fixture will follow when the tool is to operate on the workpiece.