Multi-Detector Encoder for Accurate Robot Motor Load Sensing
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Solution Overview
Problem
Conventional torque detection apparatuses for motors in industrial robots are large and prone to accuracy issues due to variations in rotation angles and friction, particularly on output shafts, which complicates high-accuracy load detection and motor control.
Innovation Solution
A driving apparatus with a motor section connected to a base via an elastic body, featuring multiple detectors for displacement information and a computing section that processes this information to determine the motor's driving amount and load, allowing for precise control and load detection using a simpler configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional torque detection apparatus uses two rotation angle detection sections, then torque can be detected, but the apparatus becomes large in scale and detection accuracy is affected by variations in rotation angle and friction
Solution Approach 1:
The patent combines the torque detection function with the existing encoder by adding a third detector to detect the rotation angle of the motor shaft. This merges two previously separate functions (position detection and torque detection) into a single integrated system, eliminating the need for separate torque detection apparatus and reducing overall system complexity while maintaining high detection accuracy
Solution Approach 2:
The encoder is designed to perform multiple functions: it detects both the rotation angle of the motor shaft (for control) and the torque (for load detection). By making the encoder multi-functional, the patent eliminates the need for separate dedicated torque detection devices, thereby reducing apparatus scale while maintaining accurate torque measurement capability
2Ease of operation
If grease is applied to the output shaft to reduce friction, then operation is smoother, but detection accuracy is affected by friction variations
Solution Approach 1:
The patent introduces an elastic body as an intermediary element between the motor shaft and the load. This elastic body isolates the detection system from the friction and variations caused by grease on the output shaft, allowing smooth operation to be maintained while preventing these harmful factors from affecting detection accuracy
Solution Approach 2:
The patent extracts the detection point from the output shaft (which is subject to friction and grease variations) and places it at the motor shaft (which can be detected with high accuracy by the encoder). By taking out the detection function from the problematic output shaft environment, the system maintains both smooth operation and high detection accuracy
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 solution enables accurate detection of motor load and precise control of motor rotation angles, even under fluctuating load conditions, by using the elastic body to reduce relative rotation angles and improve detection accuracy.
Implementation Method 1
an elastic body for connecting the motor section in a displaceable manner to a fixed section
Data Source
AI summary
Provided is an encoder, which is provided in a driving apparatus comprising a motor section configured to drive a first displacement section, which is connected to a fixed section via an elastic body, and a transmission section configured to convert a displacement of the first displacement section and transmit the displacement to the second displacement section, comprising: a first detector configured to detect first displacement information of the first displacement section; a second detector configured to detect second displacement information of the second displacement section; a third detector configured to detect third displacement information of the motor section relative to the fixed section; and a computing section configured to obtain information related to a driving amount of the motor section using the first displacement information and the second displacement information, and obtain information of a load on the motor section using the third displacement information.