# Leg Test Stand v2
<img src="images/teststand_v2_1.jpg" width="600"> <br>  

## Description

This teststand allows us to evaluate the performance of a single 2dof leg with external sensors.
The teststand has a linear guided vertical degree of freedom and a carriage that holds the leg and the motor driver electronics. The ground reaction forces are measured with a 6 axis force-torque-sensor and are transmitted to the control pc at 1kHz. The vertical position of the carriage is measured with an analog string potentiometer. The test stand can be equipped with a pull-up-motor module for automated resetting to the initial position for machine learning experiments.

* This is an updated version of the [Leg Test Stand v1](../leg_test_stand_v1#leg-test-stand-v1)
* The details of the 2dof leg are described here: [Leg 2dof v2](../leg_2dof_v2/README.md#leg-2dof-v2)
* the details of the custom electronics are described here:
  * [Details Master Board](https://github.com/open-dynamic-robot-initiative/master-board#master-board)
  * [Details Micro Driver Board](../../electronics/micro_driver_electronics/README.md#micro-driver-electronics)

## Details Leg Test Stand

<img src="details/leg_test_stand_cad_2.png" width="500"> <br>*Leg Test Stand v2 cad model*<br>

* vertical range: 85cm
* pull-force height sensor about 2N
* weight carriage with electronics and 2dof leg: 713g
* 24V power supply and ethernet connection

<img src="images/teststand_v2_2.jpg" width="500"> <br>*Carriage with 2dof leg and custom motor driver electronics  - weight: 713g*<br>

## Electronics

<img src="images/electronics_stack.jpg" width="350"> <br> *Electronics Stack - weight: 45g*

### Master Board
<img src="images/master_board_1.jpg" width="350"> <br> *Master Board v2 - weight: 19g each*
* [Master Board Documentation](https://github.com/open-dynamic-robot-initiative/master-board#master-board)

### Micro Driver Electronics
<img src="../../electronics/micro_driver_electronics/images/micro_driver_v2_1.jpg" width="300"> <br> *Micro Driver Electronics - weight: 13g*

* the micro driver board controls 2 brushless motors
* [Micro Driver Board Documentation](../../electronics/micro_driver_electronics/README.md#micro-driver-electronics)

### Height Sensor
<img src="images/string_potentiometer_1.jpg" width="300"><br>*Waycon string potentiometer*<br>

* Waycon LX-PA-40 string potentiometer
* measurement range 1000mm
* [Waycon Webpage](https://www.waycon.biz)
* [Waycon String Potentiometer Datasheet](https://www.waycon.biz/fileadmin/draw-wire-sensors/Draw-Wire-Sensor-LX.pdf)
* ordering information [below](#bill-of-materials---leg-test-stand-v2)

### Force Torque Sensor
<img src="images/ati_mini_40_ft_sensor.jpg" width="300"> <br>*ATI Mini-40-E force-torque-sensor*<br>
* 6 axis force-torque sensor
* ATI Mini-40-E with SI-40-2 Calibration
* NetBA Interface Box required
* Ethernet communication with control pc
* [ATI Mini-40 Product Page](https://www.ati-ia.com/products/ft/ft_models.aspx?id=Mini40)
* [ATI Mini-40-E Technical Drawing](https://www.ati-ia.com/app_content/Documents/9230-05-1314.auto.pdf)
* [NetBA Interface Box Technical Drawing](https://www.ati-ia.com/app_content/documents/9230-05-1327.auto.pdf)
* ordering information [below](#bill-of-materials---leg-test-stand-v2)

## Off-the-shelf Components
### Linear Guide
<img src="images/linear_guide_1.jpg" width="300"> <br>*Linear ball bearing and linear motion rod*<br>

* Linear ball bearings: KB-1
* Rod diameter 14mm
* Linear motion rods: Precision Stainless Steel Rods X46 14h6 x 1000mm
* ordering information [below](#bill-of-materials---leg-test-stand-v2)

### Aluminum profiles
<img src="images/aluminum_profile_1.jpg" width="300"> <br> *Item aluminum profile*<br>
* Item aluminum profiles - Size 8 - 40mm x 40mm
* required profile length: 2,7m
* segment lengths: 120cm / 70cm / 50cm / 30cm
* ordering information [below](#bill-of-materials---leg-test-stand-v2)

### Angle brackets
<img src="images/item_angle_connector_40mm.jpg" width="300"> <br> *Item 90 degree angle bracket 40mm*<br>
* 90 degree 40mm angle brackets
* ordering information [below](#bill-of-materials---leg-test-stand-v2)

### End caps
<img src="images/item_end_caps.jpg" width="300"> <br> *Item end caps*<br>
* end caps - size 8
* ordering information [below](#bill-of-materials---leg-test-stand-v2)

### T-slot nuts
<img src="images/t_slot_nuts_1.jpg" width="300"> <br> *Item M5 t-slot nuts*<br>
* T-slot nuts M5
* ordering information [below](#bill-of-materials---leg-test-stand-v2)

### Steel Pins
<img src="images/steel_pins.jpg" width="300"> <br> *5mm Steel Pins*<br>
* Steel Pins - 5mm x 28mm
* ordering information [below](#bill-of-materials---leg-test-stand-v2)

### Carbon-Fiber Tube
<img src="images/carbon_tube.jpg" width="300"> <br> *Carbon-fiber tube*<br>
* O.D. 6mm / I.D. 4mm / Length 30cm
* for wire management
* ordering information [below](#bill-of-materials---leg-test-stand-v2)

---
## 3D Printed Parts

<img src="images/printing_direction.png" width="400"> <br>

`The recommended printing direction for all the parts below is the positive z direction of the stl files.`

All the STL files for 3d printing the Leg Test Stand can be found here: [STL Files Leg Test Stand](stl_files).

---
<img src="details/carriage.png" width="300"> <br>
* [Carriage - STL file](stl_files/carriage.STL)
* print on FDM or SLS printer
---
<img src="details/master_board_support.png" width="300"> <br>
* [Master Board Support - STL file](stl_files/master_board_support.STL)
* print on FDM or SLS printer
---
<img src="details/stack_spacer.png" width="200"> <br>
* [Spacer Micro Driver Stack - STL file](stl_files/spacer_micro_driver_stack.STL)
* print on SLA, Multijet or Polyjet printer
---
<img src="details/linear_bearing_cover.png" width="200"> <br>
* [Linear Bearing Cover - STL file](stl_files/linear_bearing_cover.STL)
* print on FDM or SLS printer
---
<img src="details/adjustment_sleeve.png" width="200"> <br>
* [Adjustment Sleeve - STL file](stl_files/adjustment_sleeve.STL)
* print on SLA, Multijet or Polyjet printer
---
<img src="details/linear_motion_rod_attachment.png" width="300"> <br>
* [Linear Motion Rod Attachment - STL file](stl_files/linear_motion_rod_attachment.STL)
* print on FDM or SLS printer
---
<img src="details/string_potentiometer_pullup_motor_mount.png" width="280"> <br>
* [String Potentiometer and Pullup Motor Mount - STL file](stl_files/string_potentiometer_pullup_motor_mount.STL)
* print on FDM or SLS printer
---
<img src="details/pulley_pullup_module.png" width="200"> <br>
* [Pulley Pullup Module - STL file](stl_files/pulley_pull_up_module.STL)
* for pullup motor / optional
* print on FDM or SLS printer
---
<img src="details/ati_sensor_top_plate.png" width="250"> <br>
* [ATI Sensor Top Plate - STL file](stl_files/ati_sensor_top_plate.STL)
* print on FDM or SLS printer
---
<img src="details/ati_sensor_bottom_plate.png" width="300"> <br>
* [ATI Sensor Bottom Plate - STL file](stl_files/ati_sensor_bottom_plate.STL)
* print on FDM or SLS printer
---
<img src="details/motor_driver_electronics_attachment.png" width="300"> <br>
* [Motor Driver Electronics Attachment - STL file](stl_files/motor_driver_electronics_attachment.STL)
* for pullup motor electronics / optional
* print on FDM or SLS printer
---
<img src="details/stopper_attachment.png" width="200"> <br>
* [Stopper Attachment - STL file](stl_files/stopper_attachment.STL)<br>
* print on FDM or SLS printer
---
<img src="details/stopper_wing.png" width="200"> <br>
* [Stopper Wing - STL file](stl_files/stopper_wing.STL)<br>
* print on FDM or SLS printer
---

## Bill of Materials - Leg Test Stand v2
<img src="details/leg_test_stand_cad_overview_1.png" width="500"> <br>

| Description | Quantity | Ordering Information | Comments |  
| --- | --- | --- | --- |   
|2DOF Leg |1|[2DOF Leg Documentation](../leg_2dof_v2/README.md#leg-2dof-v2)|Custom assembly|
|Master Board|1|[Master Board Documentation](https://github.com/open-dynamic-robot-initiative/master-board#master-board)|Custom electronics|
|Micro Driver Board|1|[Micro Driver Board Documentation](../../electronics/micro_driver_electronics/README.md#micro-driver-electronics)|Custom electronics|
|String Potentiometer|1|Waycon LX-PA-40<br>[Waycon Distributors](https://www.waycon.biz/distributors/europe/)|1000mm measurement range<br>[Waycon String Potentiometer Datasheet](https://www.waycon.biz/fileadmin/draw-wire-sensors/Draw-Wire-Sensor-LX.pdf)|
|6 Axis Force-Torque-Sensor|1|ATI Mini-40-E<br>SI-40-2 calibration<br>[ATI Sales](https://www.ati-ia.com/company/contacts.aspx)|[ATI Mini-40 Product Page](https://www.ati-ia.com/products/ft/ft_models.aspx?id=Mini40)<br>We ordered the sensor and interface box from [Schunk](https://schunk.com/de_en/gripping-systems/product/30836-ftn-mini-40-si-40-2/) in Germany.|
|Inertia Measurement Unit|1|Lord Microstrain 3DM-GX5-25 AHRS<br>[Lord Microstrain Distributors](https://www.microstrain.com/support/distributors)| [3DM-GX5-25 AHRS Datasheet](https://www.microstrain.com/sites/default/files/3dm-gx5-25_datasheet_8400-0093_rev_o.pdf)<br>We ordered the IMU from [ZSE Electronic GmbH](https://www.zse.de/en/) in Germany.|
|Linear Ball Bearings|4|KB-1 14mm<br>[Mädler 64699814](https://www.maedler.de/product/1643/1630/2358/linearkugellager-kb-1-iso-serie-1-rostfrei-mit-deckscheiben?result=64699814)||
|Linear Motion Rods|2|Precision Stainless Steel Rods X46 14h6 x 1000mm<br>[Mädler 64799214](https://www.maedler.de/product/1643/1630/559/praezisions-wellenstahl-edelstahl-x46-rostfrei-gehaertet-und-geschliffen?result=64799214)||
|Aluminum Profiles|4|Item Size 8 - 40mm x 40mm <br>[Item 7.0.000.09](https://product.item24.de/en/products/product-catalogue/productdetails/products/line-8-construction-profiles-1001042794/profile-8-40x40-e-natural-7000009/)|Segment lengths: 120cm / 70cm / 30cm / 50cm|
|Angle Brackets|4|[Item 0.0.411.15](https://product.item24.de/en/products/product-catalogue/productdetails/products/angle-brackets-zn-1001046547/angle-bracket-set-8-40x40-41115/)|Bolts and nuts included.|
|End Caps|5|[Item 0.0.026.01](https://product.item24.de/en/products/product-catalogue/productdetails/products/caps-for-profiles-in-modular-dimensions-1001042804/cap-8-40x40-black-2601/)||
|T-Slot Nuts M5|7|[Item 0.0.480.54](https://product.item24.de/en/products/product-catalogue/productdetails/products/t-slot-nuts-st-1001042830/t-slot-nut-v-8-st-m5-bright-zinc-plated-48054/)||
|Steel Pin 5mm x 28mm|2|||
|Carbon-fiber tube 6mm|1|[R&G 7406041](https://shop1.r-g.de/en/art/740908)|Length 30cm|
|Carriage|1|[STL file](stl_files/carriage.STL)|3d printed part<br>Print on FDM or SLS printer.|
|Master Board Support|1|[STL file](stl_files/master_board_support.STL)|3d printed part<br>Print on FDM or SLS printer.|
|Spacer Micro Driver Stack|8|[STL file](stl_files/spacer_micro_driver_stack.STL)|3d printed part<br>Print on SLA, Polyjet or Multijet printer.|
|Linear Bearing Cover|4|[STL file](stl_files/linear_bearing_cover.STL)|3d printed part<br>Print on FDM or SLS printer.|
|Adjustment Sleeve|4|[STL file](stl_files/adjustment_sleeve.STL)|3d printed part<br>Print on SLA, Polyjet or Multijet printer.|
|Linear Motion Rod Attachment|2|[STL file](stl_files/linear_motion_rod_attachment.STL)|3d printed part<br>Print on FDM or SLS printer.|
|String Potentiometer and Pullup Motor Mount|1|[STL file](stl_files/string_potentiometer_pullup_motor_mount.STL)|3d printed part<br>Print on FDM or SLS printer.|
|Pulley Pullup Module|1|[STL file](stl_files/pulley_pull_up_module.STL)|3d printed part / optional<br>Print on FDM or SLS printer.|
|ATI Sensor Top Plate|1|[STL file](stl_files/ati_sensor_top_plate.STL)|3d printed part<br>Print on FDM or SLS printer.|
|ATI Sensor Bottom Plate|1|[STL file](stl_files/ati_sensor_bottom_plate.STL)|3d printed part<br>Print on FDM or SLS printer.|
|Motor Driver Electronics Attachment|1|[STL file](stl_files/motor_driver_electronics_attachment.STL)|3d printed part / optional<br>Print on FDM or SLS printer.|
|Stopper Attachment|2|[STL file](stl_files/stopper_attachment.STL)|3d printed part<br>Print on FDM or SLS printer.|
|Stopper Wing|1|[STL file](stl_files/stopper_wing.STL)|3d printed part<br>Print on FDM or SLS printer.|
|Carbon Fiber Rod|1||O.D. 5mm<br>I.D. 4mm<br>Length 30cm|
|Fasteners M3 x 8|16||Fasteners linear bearing covers|
|Fasteners M3 x 16|4||Fasteners 2dof leg|
|Fasteners M2,5 x 22|4||Fasteners electronics stack|
|Fasteners M2 x 5|4||Fasteners Master Board|

## Preparing the 3D Printed Parts

<img src="details/test_stand_preparation_1.png" width="450"><br>

<img src="details/test_stand_preparation_2.png" width="450"><br>

<img src="details/test_stand_preparation_3.png" width="350"><br>

<img src="details/test_stand_preparation_4.png" width="400"><br>

<img src="details/test_stand_preparation_5.png" width="400"><br>

<img src="details/test_stand_preparation_6.png" width="400"><br>

## View the Teststand Cad Model in your Web Browser
<a href="https://open-dynamic-robot-initiative.github.io/cad_files/leg_test_stand_v2"><img src="details/leg_test_stand_cad_1.png" width="400"></a><br> *Leg Test Stand v2 - Click on the picture to view the cad model in your browser* <br>

* You can download the Solidworks CAD files [here](solidworks_files/leg_test_stand_v2.zip).

## More Information
[Open Dynamic Robot Initiative - Webpage](https://open-dynamic-robot-initiative.github.io)  
[Open Dynamic Robot Initiative - YouTube Channel](https://www.youtube.com/channel/UCx32JW2oIrax47Gjq8zNI-w)   
[Open Dynamic Robot Initiative - Forum](https://odri.discourse.group/categories)  
[Open Dynamic Robot Initiative - Paper](https://arxiv.org/pdf/1910.00093.pdf)  
[Hardware Overview](../../README.md#open-robot-actuator-hardware)  
[Software Overview](https://github.com/open-dynamic-robot-initiative/open-dynamic-robot-initiative.github.io/wiki)

## Authors
Felix Grimminger

## License
BSD 3-Clause License

## Copyright
Copyright (c) 2019-2021, Max Planck Gesellschaft and New York University