Robot Arm Speed Control With Output-Side Gear Position Feedback
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Solution Overview
Problem
Existing robot control systems face challenges in accurately controlling the position of movable units due to position errors in transmission units, particularly in wave reduction gears, which require complex measurements and are not suitable for mass production, and do not account for deflection errors.
Innovation Solution
A control device that uses input and output detection values from position sensors to perform speed control, potentially with a low-pass filter to stabilize control and includes a force detection unit to account for deflection, allowing for accurate speed control without pre-measuring transmission unit errors and effectively handling detection period deviations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If wave reduction gear is used for speed control, then speed control capability is improved, but position accuracy deteriorates due to angular transmission error
Solution Approach 1:
The patent implements feedback control by detecting the output side operation position using an output position detection sensor and comparing it with the command position. The feedback control unit adjusts the drive force based on the position deviation, thereby compensating for the angular transmission error of the wave reduction gear and maintaining accurate position control at high speeds.
Solution Approach 2:
The patent introduces an output position detection sensor as an intermediary element to directly measure the actual output position. This sensor acts as a mediator between the transmission unit and the control system, providing real position feedback that enables correction of transmission errors without modifying the wave reduction gear itself.
2Manufacturing precision
If angular transmission error characteristics are measured in advance to suppress vibrations, then position accuracy is improved, but manufacturing complexity increases due to individual measurement requirements
Solution Approach 1:
The patent enables the system to self-adjust by using real-time feedback from the output position detection sensor. Instead of requiring pre-measurement and calibration of each wave reduction gear's angular transmission error characteristics, the system automatically compensates for individual variations through feedback control, eliminating the need for complex individual characterization during manufacturing.
Solution Approach 2:
The patent dynamically adjusts control parameters (drive force, speed commands) based on real-time position feedback. This allows the system to adapt to individual transmission unit characteristics without requiring pre-measurement, as the control parameters are continuously optimized during operation rather than being fixed during manufacturing.
3Device complexity
If speed control is performed using only input detection value, then device complexity is reduced, but position accuracy deteriorates at higher speeds due to transmission unit position error
Solution Approach 1:
The patent implements feedback control by detecting the output side operation position using an output position detection sensor and comparing it with the command position. The feedback control unit adjusts the drive force based on the position deviation, thereby compensating for the angular transmission error of the wave reduction gear and maintaining accurate position control at high speeds.
Data Source
AI summary
A control device for controlling a robot including an arm driven via a reduction gear by a motor generating a drive force, the control device comprising a processor that is configured to execute computer-executable instructions so as to control a robot, wherein the processor is configured to perform speed control on the arm by using an input detection value from an input position detection sensor which detects an input side operation position of the reduction gear, and an output detection value from an output position detection sensor which detects an output side operation position of the reduction gear.