Piezo Ring Motor Slip Detection via Pulse Evaluation
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Solution Overview
Problem
Piezo ring motors (PRMs) experience slippage during overloads, leading to loss of angular position precision due to undetectable slip between the drive ring and shaft, preventing precise control in exceptional situations.
Innovation Solution
Implementing a method to detect and quantify slip using a drive controller that evaluates pulses generated during slippage, allowing for precise determination of the actual angular position through an evaluation circuit with filters and comparators, and a microcontroller for digital processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If frictional connection or micro-serrations are used between shaft and drive ring, then torque transmission is improved, but slippage occurs during overload causing loss of angular position precision
Solution Approach 1:
The patent implements a feedback mechanism where the actuator monitors its own operational state by detecting pulses generated during slip events. The drive controller evaluates these pulses to determine the magnitude of slippage and compensates for the angular position deviation, thereby maintaining positioning precision even when slippage occurs during overload conditions
Solution Approach 2:
The patent introduces an intermediary sensing mechanism where the actuator serves dual purposes: both as the driving element and as a sensor. The actuator detects slip events through generated pulses during micro-serration skipping, acting as an intermediary between the mechanical drive system and the control system, enabling quantitative determination of slippage without adding separate sensors
2Device complexity
If quantitative determination of slip is not implemented, then device complexity is reduced, but compensation for angular position deviation becomes impossible
Solution Approach 1:
The actuator performs self-diagnosis by detecting slip events through pulses generated during micro-serration skipping. The drive controller evaluates these self-generated signals to quantitatively determine slippage magnitude, enabling the system to monitor and compensate for its own deviations without requiring external measurement devices or complex additional sensor systems
Solution Approach 2:
The patent utilizes changes in the actuator's operational parameters during slip events. When micro-serrations skip due to overload, the actuator generates characteristic pulses that change in frequency and pattern. The drive controller evaluates these parameter changes to quantitatively determine the magnitude of slippage, converting mechanical slip into measurable electrical signals
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 precise control of the actuator's shaft to a specific angular position even during overloads by quantitatively determining slippage, maintaining accuracy and reliability.
Implementation Method 1
a piezoelectric actuator (8, 9) which can be excited by a sinusoidal control signal to a change in length
Implementation Method 2
the frictional connection between the shaft and the drive ring
Implementation Method 3
micro-serrations between the shaft and the drive ring
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
A method for operating an actuating drive and/or an actuating drive are known, wherein the actuating drive comprises a shaft and a drive ring on which at least two drive elements engage. The drive elements comprise actuators, which are controlled by a drive controller, wherein the shaft is moved into a defined angular position by means of the actuators via the drive ring. An actuating drive of this type is also known as a piezo ring motor (PRM). Until now, a quantitative detection of the occurring slippage has not been possible for these piezo ring motors, so that in case of slippage no precise selection of a defined angular position can be performed. A method is proposed, wherein slippage occurring between the drive ring (4) and shaft (5) is detected by the drive controller (20) in that the drive controller (20) evaluates a pulse generated by at least one of the actuators (8; 9) and that the occurring slippage is quantified, so that the drive controller (20) can always determine the actually assumed angular position of the shaft (5). The method according to the invention is intended for actuating drives provided with piezo ring motors.