Contact Detection Using Actuator Vibration in Data Storage
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Solution Overview
Problem
Data storage devices face challenges in reliably detecting head-to-media contact due to decreasing fly heights and increased recording density, leading to potential detrimental contacts and difficulties in wear-free contact detection.
Innovation Solution
A method involving applying a known frequency input signal to an actuator in the transducing head, processing the output signal to extract signal components, and incrementally increasing power levels to determine contact, utilizing a high frequency pulse wave pattern to enhance signal-to-noise ratio and reduce contact-induced wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fly height is decreased to increase recording density, then recording density is improved, but contact reliability deteriorates
Solution Approach 1:
The patent applies mechanical vibration by driving the actuator with a periodic signal at a specific frequency (e.g., 1 kHz) to generate vibrational motion in the transducing head. This vibration creates measurable signals when the head contacts the media, enabling reliable contact detection even at decreased fly heights. The vibrational frequency is chosen to be distinct from operational frequencies to avoid interference.
Solution Approach 2:
The patent replaces traditional mechanical contact detection methods with an electrical signal-based approach. Instead of relying on mechanical sensors or complex mechanical monitoring systems, the invention uses electrical signals driven through the actuator and read through the transducer to detect contact conditions, simplifying the detection system while improving reliability.
2Manufacturing precision
If active clearance control is implemented, then clearance control precision is improved, but contact detection reliability deteriorates
Solution Approach 1:
The patent makes the actuator and transducer serve multiple functions: they not only control clearance actively but also serve as the detection mechanism for contact. By using the same components for both control and detection, the system avoids adding separate detection systems that would compromise reliability, while maintaining precise clearance control capability.
Solution Approach 2:
The patent implements feedback by continuously monitoring the electrical signal response from the transducer during actuator operation. The detected signal information is fed back to control the actuator, creating a closed-loop system that maintains optimal clearance while providing reliable contact detection through the same actuation mechanism.
3Device complexity
If traditional contact detection methods are used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent applies self-service by using the actuator and transducer to detect their own operational state. The actuator drives the transducer, and the transducer's response to the actuator's motion provides direct feedback about contact conditions. This self-detection approach eliminates the need for separate detection systems, maintaining simplicity while achieving high measurement precision.
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
The method effectively detects head-to-media contact with improved signal-to-noise ratio and reduced wear, enabling accurate calibration and active clearance control in data storage devices.
Implementation Method 1
an actuator for actuating the transducing head
Implementation Method 2
an actuator for actuating the transducing head
Implementation Method 3
a transducer for reading and writing data to the storage media
Implementation Method 4
a transducer for reading and writing data to the storage media
Implementation Method 5
A controller extracts at least one signal component from the output signal at the same known frequency or a harmonic of the same known frequency as the input signal applied to the actuator
Data Source
AI summary
A method of detecting a contact between a transducing head and a storage medium is provided. The method applies an input signal, having a select power level and known frequency, to an actuator for actuating the head. An output signal is obtained in response to the input signal. At least one signal component is extracted from the output signal at the same or a harmonic of the same known frequency as the input signal applied to the actuator. Whether the at least one extracted signal component indicates a contact between the head and the medium is determined. The power level of the applied wave pattern is increased incrementally until the extracted signal component indicates a contact between the head and the storage medium.