Hard disk drive with voltage driven voice coil motor and. The shaft had a slotted opto sensor iirc there was only one to feed back position info. Securing and control of this movement is of crucial importance for performing elementary function of hard drives. Hard disk drive with voltagedriven voice coil motor and. With a worm gear drive the system wont be reversible, so the flag should stay wherever you last put it when you power down the motor. You could in theory use the fg output to do closedloop control of the motor speed using a separate microcontroller. This indicates a slight reduction in flow rate, which seems reasouable given the situation as specified.
Voice coil systems using adapted loudspeakers offer fast extinction, but again, over a limited shutter area. Hard disk drive with voltage driven voice coil motor and model. The term voice coil comes from one of the first applications. It consists of a copper coil wound around a former and a permanent magnet.
Those old hard drives used monster 4 inch voice coils and magnet assemblies big as a loaf of bread. Seems like there is no end to the uses of old hard drives. A voice coil is a part of hsa, the voice coil and the magnets form a voice coil motor or vcm. The si9961a contains all of the power and control circuitry necessary to drive the vcm that is typically found in 31 2 inch hard disk drives and optical disk drives. Those are the original ibm pcat hard disks usually called mfm disks which needed a controlling card.
Assuming you have enough kinetic momentum to carry it through, you can monitor the velocity of a stepper motor by not driving a particular step and reading the coil as an input device instead. Hard drives have highspeed lowprofile motors that can be reused. I have made some experiments of using also hard disk drive stepper motor. The new l7208 hdd motor controller integrates all of the circuits needed to control and drive the hdd spindle motor and voice coil actuator including all the necessary powerfet devices and is designed to save space and to minimize the drive s power consumption. Pdf halbach magnetic circuit for voice coil motor in hard disk. In my experiments i have used st506412 interface hard disk drives. Either make the flag position bistable somehow so that the voice coil only needs to be activated to move it between the positions, or find another way to do this. All hard disk drives being manufactured today use voice coil actuators because stepper motors cant achieve the degree of accuracy necessary. I would start by googling for the chip part numbers near the stepper motor on your hard disk and build a driver from them. Pid voice coil head actuator with linear hall sensor. Not sure how relevant this is, but in an old hard drive i took apart some years ago the heads were positioned not by a voice coil but by a nut running on a threaded shaft rotated by a dc motor.
You can download the source code and and additional information of this vcm on. Here i show you how to turn an old hard drive into a speaker. The drives contained in a hdd dvd recorder are standard hard drives, though you will have to remove it from the recorder and reformat it. Description smp circuit the ka2811c is a monolithic onechip ic which includes spm spindle motor driver, vcm voice coil motor driver and peripheral driver, designed for driving hdd motor. Do odczytu pozycji ramienia wykorzystalem liniowy czujnik halla. A voice coil actuator controls the movement of the readwrite head following the principle of electromagnetic attraction and repulsion. Simulations and experimental results proved effectiveness of the proposed magnet array in the voice coil motor for a commercial hard disk drive. Hard disk drive voicecoil laser shutter actuator hacked. Current hdds speed is too fast to cause this ic hot and damaged. We drove the coil of an old hard disk drive head motor with a differential current supplied by a ucc27425d which in turn was driven directly from the output pin of an arduino. The device contains a selectable transconductance loop. Introduced by ibm in 1956, hard disk drive was the dominant secondary storage device for general purpose computers by the early 1960s and still is the dominant form of storage. Hard drive stepper motor with high speed spinup circuit.
I have done videos of this in the past but never a tutorial on how it is done. And they used cast aluminum carriages with ballbearing wheels and machined rails to run on. Difference between hard disk and hard drive compare the. A tutorial on control design of hard disk drive selfservo. Halbach magnetic circuit for voice coil motor in hard disk. A hard disk voice coil assembly, also called actuator, is a linear control device within a hard drive responsible for positioning the read write heads. Brushless motor drivers then energize these coils in a vary carefully timed.
A motor actually the correct term is actuator called voice coil moves the arm. The linear voice coil motor vcm is a direct drive and hysteresisfree. Many modern disk drive drive motors use voice coil control systems, which makes another story. To meet the power handling capability required for a high. In this paper we describe a head servopositioning system for hard disk drives hdds, in which the usual current command for the voice coil motor h. Optimal control design of a voice coil head actuator in a. Brushless hdd motor driver from 9v and painters tape. Fwiw to your fyi, hard drives used to use stepper motors for head positioning before voice coils took over. In recent years, the most common application for voice coils has been to move the heads inside computer disk drives, but theyre also widely found in medical devices, mirror controls, and oscillating systems. Hdd actuator is a device which moves head arm assembly. There are a number of people offering onweb examples of hdd voice coil drivers used for other purposes.
In this paper, we describe the voice coil modelbased control vcmc, a new solution for driving the voice coil motor vcm in hard disk drives hdds, in which the usual current driver for the vcm has been replaced by a voltage driver. Filters a filter is placed at the edge of the platters to catch any debris created or disturbed by them. The adaptation of the driver compensates for the variations of vcm resistance and is performed either during seek operations and track following. During the hdd servos, one of the most important parts is servo. Fuzzy logic control of voice coil motor hard disk drives. Linear voice coil motors actuators and micro voice coil. Realization of a hard disk drive head servopositioning system with. A hard disk drive hdd, hard disk, hard drive, or fixed disk is an electromechanical data storage device that uses magnetic storage to store and retrieve digital information using one or more rigid rapidly rotating disks platters coated with magnetic material.
Linear dc motors, voice coil motors vcm or voice coil actuators vca are the simplest type of electric motors. More often than not its the logic board that fails in a hard drive and the motors are ok this is a simple program for a pic16f84 that changes the bit pattern for switching the fet coil drivers. The si9961a is a linear actuator voice coil motor driver suitable for use in disk drive head positioning systems. For high starting torque and high speed, spm circuit employes wss waltz step start method for starting the motor and can drive up to 2a. A rotarytype voice coil motor vcm is widely used as a highspeed and accurate positioning actuator in hard disk drives hdds. The voice coil driver l6246 is a linear power amplifier designed to drive single phase bipolar dc motors for hard disk drive applications. Voice coil motor based hard disk drive this indicates a slight reduction in flow rate, which seems reasouable given the situation as specified. Originally, this meant a type of linear actuator that drives the coils of a speaker, but the motor for driving the head of a hard disk hdd has also been recently. The ba6832fs is a voice coil motor driver used for moving the heads of hard disc and massstorage floppy disc drives. To get rid of the noise, you will have to use a much higher pwm frequency. Winchester and non winchester hard disk drive, voice coil and stepper motor mechanism. The motor shield is a reasonably good match for the voice coil then.
Be used to drive hdd spindle motor or voice coil motor. The motors all run pretty well the hard drive motor is around 6000rpm with a 12v supply, and the zip drive motor is around 15000rpm way too high for the original purpose. Friction of the nutthread was probably enough to hold position. A tutorial on control design of hard disk drive selfservo track writing jianbin nie and roberto horowitz eblock vcm.
To meet the power handling capability required for a. To position it, you will need either feedback or a spring to work against, as others have already said. Hard disk drive with voltagedriven voice coil motor and modelbased control abstract. Applying a voltage across the terminals of the motor causes the motor to move to one direction. Hard disk drive hdd hard drive a hard disk drive hdd is a secondary data storage device used for storing and retrieving digital information in a computer. Stepper motor actuators a stepper motor is an electrical motor that can step, or move from position to position, with mechanical detents or clickstop positions. Other defuzzification strategies exist such as simply using the output of the decision rule with the highest membership value lee, 1990b. The main components of a hard drive as seen in the following figure are. We have developed a highspeed laser shutter based on voice coil actuators found in generic hard disk drives. According to incomplete statistics, 70% hdd fault were caused by this motor combo ic damage.
The paper presents a novel approach for driving a voice coil motor vcm in a hard disk drive hdd, based on an adaptive voltage driver. Just a prototype, and at the beginning a unique voice coil motor would be fine, to. Its task is, not only to start and secure continuous movement of hard drive head assembly, but also to fully control it. Its well within the capabilities of an arduino to drive one of these. It also controls voice coil positioning, spindle motor speed, overall power management, and the transfer of data to and from the hard drive. As snoopen says you want a voice coil driver or actuator. A stepper motor is a dc brushless synchronous motor is it not. Hard drive technical guide and components southbit cape town. The voice coil assembly is reliable as there are few mechanical components required.1358 215 945 1000 526 642 695 1277 1368 779 21 82 1181 1212 1510 139 429 33 90 879 901 967 1055 1525 445 472 1526 542 913 1300 1392 1 461 1027 1001 535 1238 270 1457