Robotic Arm Control Device for Direct Teaching
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Solution Overview
Problem
Existing direct teaching methods for robots are complicated due to the need for force sensors to detect external forces, making fine-tuning of robotic arm or tool positions difficult during manual operation.
Innovation Solution
A method that restricts the movement of a standard point on the robotic arm or tool to a given route, using axis angle detection to generate position instruction values that assist the teaching person in positioning the arm or tool, eliminating the need for force sensors and allowing for easier fine-tuning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a force sensor is provided to detect external force applied to the wrist part, then the robot can operate by compliance control, but the device complexity increases and fine tuning of position becomes difficult
Solution Approach 1:
The patent removes the force sensor from the wrist part and extracts the external force detection function to the base position. By detecting external forces at the base rather than requiring a force sensor at the wrist, the system eliminates the complex sensor while maintaining compliance control capability. The base position detection avoids the complexity of wrist-mounted sensors while still enabling the robot to respond to external forces applied during direct teaching.
Solution Approach 2:
The patent introduces a position sensor at the base as an intermediary element. Instead of directly measuring external forces at the wrist with a force sensor, the system uses base position detection to infer and respond to external forces. This intermediary approach simplifies the overall system while maintaining the ability to perform compliance control during direct teaching operations.
2Ease of operation
If the robot operates based on detected external force, then compliance control is achieved, but fine tuning of the position of the robotic arm or tool becomes difficult
Solution Approach 1:
The patent segments the control function by separating external force detection from position control. The base position sensor detects external forces, while the wrist position is controlled independently through the teaching operation. This segmentation allows the wrist position to be finely tuned during direct teaching without being overly influenced by external force variations, improving positioning precision while maintaining ease of operation.
Solution Approach 2:
The patent replaces the mechanical force sensing system at the wrist with a positional detection system at the base. Instead of using a force sensor to directly measure external forces at the tool end, the system uses base position changes to detect and respond to external forces. This substitution improves position control precision during fine tuning operations while maintaining the compliance control functionality needed for ease of operation.
3Difficulty of detecting and measuring
If a force sensor is provided on the wrist part, then external force detection is enabled, but the control system becomes complicated
Solution Approach 1:
The patent extracts the external force detection function from the wrist part and relocates it to the base position. By using a position sensor at the base to detect external forces rather than a force sensor at the wrist, the system simplifies the control architecture. The base position detection provides sufficient information for compliance control without requiring complex wrist-mounted sensing and control systems.
Solution Approach 2:
The patent creates a simplified model of external force detection by measuring base position changes rather than directly measuring wrist forces. This copied approach uses readily available position sensor data at the base to infer external force conditions, avoiding the need for complex force sensing systems at the wrist while maintaining the essential detection capability needed for compliance control.
Data Source
AI summary
By repeating for each control axis, that an axis angle of each control axis of an arm is detected during a direct teaching of a robot, a current position of a standard point defined on the arm or a tool is obtained based on the axis angle, a position instruction value that uses a position obtained by projecting the current position on a given movement route (moving direction) is generated as a target position, and each control axis is driven based on the position instruction value, until a deviation of an instruction angle corresponding to the position instruction value and the detected axis angle, or a deviation of the position instruction value and the current position of the standard point corresponding to the detected axis angle reaches a given value or below, the robot is taught, after the deviation becomes the given value or below, positional information on the arm.