Robot Hand Current Sensing for Duplicate Workpiece Pickup
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Solution Overview
Problem
Existing workpiece transport apparatuses require expensive dedicated sensors to detect duplicate taking-out of workpieces, necessitating a cost-effective solution for detection without such sensors.
Innovation Solution
A workpiece transport apparatus equipped with a robot-mounted hand device, a current measurement section, and a workpiece number detection section that measures motor current values to differentiate between the expected and actual number of workpieces held, using threshold values to determine duplicate taking-out without dedicated sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If dedicated sensors are mounted in the hand device or check station to detect duplicate taking-out of workpieces, then detection accuracy is improved, but device cost increases
Solution Approach 1:
The motor serves itself by providing current value information that indicates the number of workpieces held. Instead of requiring external dedicated sensors, the existing motor's electrical characteristics are utilized to detect duplicate taking-out, making the detection system self-sufficient and eliminating additional expensive components
Solution Approach 2:
The patent replaces the mechanical/optical dedicated sensor system with an electrical measurement system. By measuring the current value of the motor that drives the drive axis, the system substitutes complex sensor-based detection with simpler electrical parameter measurement, reducing device cost while maintaining detection capability
2Reliability
If dedicated sensors are used for detecting duplicate taking-out of workpieces, then detection reliability is improved, but ease of manufacture deteriorates
Solution Approach 1:
The motor serves multiple functions: it drives the drive axis to operate the movable part and simultaneously provides detection information through its current value. This multi-functionality eliminates the need for separate dedicated sensors, simplifying manufacturing while ensuring reliable detection of duplicate workpiece taking-out
Solution Approach 2:
The existing motor system provides its own detection capability through current measurement, eliminating the need for additional sensor installation and calibration processes. This self-service approach simplifies manufacturing procedures while maintaining detection reliability
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
Enables accurate detection of duplicate taking-out of workpieces at a lower cost, preventing incorrect transport and improving detection accuracy regardless of workpiece material, without relying on dedicated sensors.
Implementation Method 1
a current measurement section configured to measure a current value of a motor that drives the drive axis
Data Source
AI summary
A workpiece transport apparatus for transporting a workpiece includes: a hand device; a moving device that includes a movable part mounted with the hand device and that includes at least one drive axis configured to operate the movable part; a current measurement section configured to measure a current value of a motor that drives the drive axis; and a workpiece number detection section configured to detect that a number of workpieces held by the hand device is different from an expected number based on a comparison result between the current value measured by the current measurement section when the hand device holds the workpiece, and a predetermined threshold value.