Motor Control Standstill Monitoring for Animal Brushing Devices
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Solution Overview
Problem
Existing animal brushing devices require complex mechanical efforts and additional sensors to detect an animal's desire for brushing, which can be cumbersome and prone to failure in harsh environments, especially when trying to detect passive rotation of a brush without external sensor connections.
Innovation Solution
Implementing standstill monitoring within the motor control device using terminal voltage and current information, eliminating the need for external sensors by deriving passive rotation indicators from available motor data, suitable for both permanent excitation and asynchronous motors like three-phase asynchronous motors with squirrel-cage rotors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotation sensor is arranged on or between the motor and the brush to detect passive rotation, then the detection of animal-induced brush rotation is enabled, but the system requires additional cables and sensor modifications that are prone to failure in harsh operating conditions
Solution Approach 1:
The patent extracts the standstill monitoring function from external sensors and relocates it to the motor control unit's existing evaluation electronics. This eliminates the need for separate rotation sensors and their associated cable connections, thereby removing the reliability issue while preserving the passive rotation detection capability.
Solution Approach 2:
The motor control unit's evaluation electronics, originally designed for motor control, are made multi-functional by enabling them to also perform standstill monitoring. This allows the same electronics to serve dual purposes: controlling motor operation and detecting passive rotation through terminal voltage and current analysis, eliminating the need for dedicated sensing hardware.
2Ease of operation
If a liftable brush mounting is used to allow animals to trigger the brush, then the animal can signal its need for brushing, but the mechanical structure requires considerable effort and may be too heavy for the animal to lift
Solution Approach 1:
The patent replaces the mechanical liftable brush mounting system with an electrical detection system. Instead of requiring physical brush lifting to trigger operation, the system detects passive rotation through electrical signals (terminal voltage and current) generated when the brush rotates due to animal contact. This substitution eliminates the need for heavy mechanical structures while maintaining the animal's ability to initiate brushing.
3Measurement precision
If standstill monitoring is implemented using external sensors, then passive rotation can be detected, but additional components and cables increase system complexity and potential failure points
Solution Approach 1:
The patent merges the standstill monitoring function with the existing motor control unit. By combining these functions, the system uses the same evaluation electronics and power supply for both motor control and passive rotation detection, eliminating the need for separate sensor systems and reducing overall device complexity.
Solution Approach 2:
The motor control unit is designed to perform multiple functions: it controls motor operation and simultaneously monitors for passive rotation through its existing evaluation electronics. This multi-functionality eliminates the need for dedicated sensing hardware, reducing system complexity while maintaining detection capability.
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 simplifies the detection of passive rotation, reduces mechanical burden on animals, and enhances reliability by minimizing additional components and cables, allowing for efficient and robust operation in various environments.
Implementation Method 1
the information about passive brush rotation does not originate from an external sensor, but is derived from the information available in the motor control unit. Specifically, the motor control unit has information about the terminal voltage and/or terminal current of the motor, i.e., the current in one or more or all of the motor's stator windings.
Data Source
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AI summary
The invention relates to a device (1;1') for brushing animals with at least one brush (11,12;11') rotatably mounted about an axis, which can be driven by a motor (6;6') in the form of an AC or three-phase motor coupled to a motor control unit (16;16'), wherein, when the motor (6;6') is at rest, its rotation is continuously monitored in order to detect any rotation of the motor (6;6') not triggered by a control signal and to use this as a criterion for switching on the motor (6;6'), and wherein, for the standstill monitoring, no separate sensor is provided from the motor control unit (16;16'), but rather the standstill monitoring is limited to evaluation electronics within the motor control unit (16;16') or is implemented as a software function within the motor control unit (16;16').