Motion-Control Rig V3

I built this rig with my father, from wood, aluminium, pillow-block bearings and a second-hand slewing ring. Its job is to move the camera along exactly the same path again, so a miniature can be photographed in several passes and the passes line up.

Specification

Axes
8
Reach
1.2 m radial arm, 1 m dolly
Kinematics
Raspberry Pi 5, damped least squares
Drives
ESP32, TMC2209 stepper drivers
Camera
Fujifilm X-S20
Build
Wood, aluminium, pillow-block bearings, second-hand slewing ring
Repeatability
Not measured yet
Stack
Raspberry Pi 5 · ESP32 · TMC2209

Status

Operational· Started [TODO: date]

The rig. [TODO: photo]

Control

A Raspberry Pi 5 solves the kinematics of the camera path, using damped least squares. An ESP32 with TMC2209 drivers turns the result into stepper movement.

Miniature08 Dolly02 Tilt03 Radial05 Tilt 207 CounterweightPass 0108 0.000 m02 62.3°03 0.137 m05 -76.9°

Drag the camera

Schematic, side view, not to scale: four of the eight axes solving for the camera with damped least squares, the method the rig uses. Each dot is one exposure; pass after pass, they land on the same dots.

Axes

No. Axis
01 Base pan
02 Tilt
03 Radial
04 Pan 2
05 Tilt 2
06 Roll
07 Travelling counterweight
08 Dolly

The radial arm reaches 1.2 m, the dolly 1 m. The camera is a Fujifilm X-S20.

Next

Repeatability is not measured yet. That is the next job. [TODO: method and result]

Where it is used

The rig shoots KORETH and the ALIVE pipeline.

Log

  1. Eight axes from wood, aluminium and a used slewing ring