Analysis of the Kalman Filter Algorithm

July 7, 2017

MotivationThe Kalman filter finds applications in extracting useful data from inherently noisy sources. One common application is smoothing sensor data. In order for most sensor data to be effectively employed in applications like control loops or navigation systems it must first be filtered in a manner that removes noise but, does not introduce an unacceptable amount of additional error or increases processing and memory load on the system. In this regard the Kalman filter excels. The Kalman filter can also be extended to combine data from multiple input sources to further reduce the error in a signal or sample. This property has many applications in the area of sensor fusion. Kalman filter sensor fusion is commonly used in robotic control systems. A common use case is autonomous vehicle navigation and control eg. Quadcopters or spacecraft. Additionally, the Kalman filter is often used in analog and digital signal processing. The Kalman filter algorithm enjoys implementations in both software and hardware.

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CNC Conversion Mechanical

October 29, 2014

Mini Mill

Hi Torque Mini Mill.

Unboxing the kit.

CNC FUSION KIT

Unfortunately, this company is no longer around. Thankfully, there are other kits available to perform this conversion.

Solid Column upgrade The original hi torque mini mill from Little Machine Shop had a gimmicky tilting column. While it was nice to be able to tilt the mill head it was impossible to tram the mill. This solid column is complete replacement for the tilting column.
Disassembly

X/y stage separated from the rest of the mill. The tilting column version only required removing one large bolt on the back of the mill.

Tilting column with z axis

Front of the tilting column with the mill head removed.

X and Y axis

The ballscrew is slightly too long. So we will have to do a little metal removal.
The ballscrew hits the other side of the casting
Grinding out a small pocket to fit the ballscrew end. This was done with a rotary tool and a mini end mill.

Mounting the x ballscrew to the bottom of the x. I believe this mounted using the existing tapped holes.

Assembled X and Y table

Z axis

Tapping the mounting holes for the z axis ballscrew mount The z axis ballscrew is positioned off to the side of the main column. We have to attach a metal plate to the top of the column in order to mount the ballscrew. This requires locating the mounting plate. Using center taps to locate the mounting holes. Drilling the mounting holes. Tapping the mounting holes.

Z axis ballscrew mounted on the main column. Metal mounting plate attached to the top of the column. Ballscrew nut attached to the mill head via two mounting holes.

Another view of the z axis.

Electronics

Controller

Beagle Bone Black

Interface card

C10- PARALLEL PORT INTERFACE CARD

Motor Controllers

M880A

M880Am.pdf

Control Board

View of the inside of the electronics enclosure. This is a NEMA 4 enclosure the minimum you need when dealing with possible over spray.

Electronics mounted in the enclosure. Top left parallel port interface card mounted on standoffs above the beagle bone black. Top right the CNC electronics from the original hi torque mini mill. Left middle - A DC to DC power supply to produce 5v for all 5 volt components including the beagle bone black and parallel port card. Center middle - Stepper motor controllers. Right middle 36 v power supply. Bottom Din rail mounted terminal strip.

Spindle Control

The original mill only had a simple pot to turn for spindle control. This will not work for a CNC that needs to vary the spindle control throughout a job. To correct this short coming we’re going to replace the original spindle control with a 0-10 volt control. This will allow the beagle bone black him costume the books speed and direction via then parallel port adapter.

CNC Spindle Control Upgrade Kit, Mini Lathe and Mini Mill

4213CNCSpindleControlUpgradeKit.pdf