Movable Machine Component Homing via Actuator Stall Detection
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Solution Overview
Problem
Industrial machines face challenges in accurately calibrating moveable components without increasing complexity and cost by incorporating additional sensors, which are often required to enhance operational speed and accuracy.
Innovation Solution
A system that uses motor feedback from an actuator's drive motor to identify a triggering event, such as a torque rise, to define the initial position of a moveable machine component, eliminating the need for auxiliary sensors and simplifying the design and control strategy. This system includes a mechanical stop to initiate the torque rise during calibration, allowing for the definition of a null point as the initial position, and performs a confirmation movement path to ensure accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If additional sensors or more sophisticated sensors are incorporated into the machine to monitor component movement and facilitate initial calibration, then the machine's accuracy is improved, but the cost and complexity of the machine increases
Solution Approach 1:
The system uses the actuator's own drive motor feedback to perform calibration functions. The drive motor's performance characteristics (torque, speed) are monitored to automatically identify triggering events and define home positions, eliminating the need for separate auxiliary sensors and making the system self-calibrating
Solution Approach 2:
The drive motor serves multiple functions: it acts as both the actuator for moving machine components during normal operation and as a sensor during calibration sessions by monitoring its own performance characteristics to detect triggering events and define positions
2Speed
If additional sensors are incorporated into the machine to enhance operational speed and accuracy, then the machine's operational speed is improved, but the number of surfaces susceptible to accumulating debris increases
Solution Approach 1:
The solution extracts and eliminates the auxiliary sensors from the system by using the existing drive motor feedback for calibration purposes, thereby removing the additional surfaces that would accumulate debris while maintaining calibration functionality
3Productivity
If the actuator operates at higher speeds to increase productivity, then the machine's productivity is improved, but the precision of position calibration becomes more difficult
Solution Approach 1:
The system dynamically adjusts operational parameters by performing calibration at reduced speeds and torques during calibration sessions, then transitioning to full operational speeds during production, allowing precise calibration without compromising productivity during normal operation
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 automatic and repeatable calibration of industrial machines with fewer sensors, reducing debris accumulation and maintaining operational efficiency while simplifying the machine's design and control strategy, thereby enhancing productivity and accuracy without increasing costs.
Implementation Method 1
the actuator drive motor's performance characteristics while it drives a moveable machine component... The triggering event may correspond to an anomalous performance characteristic value, such as a substantial torque rise
Implementation Method 2
A mechanical stop, which may be a pin or the like, may be arranged within a travel path of a moveable machine component to provide a rigid stop point or obstruction. During the calibration session, the actuator purposely drives the moveable machine component into the stop to initiate the torque rise at the moment of impact
Data Source
AI summary
A system is provided that can automatically calibrate or define a home or initial position of a moveable component of an industrial machine. During the calibration procedure, an actuator may be operated in a low speed and/or low torque mode to drive the component until the component contacts a mechanical stop. This provides a hard-stop of the component's movement while the actuator attempts to further drive the component, which creates a stall condition of the actuator. A control system monitors that actuator's performance characteristics and is configured to identify an anomalous performance characteristic(s) value that corresponds to the actuator's stall condition as a triggering event. When the control system identifies the triggering event, it defines the component's position as a null point and determines a zero point to define an initial operational position of the component as a function of the null point.