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tracking all untracked changes into newborn Mk5.2 hand #419

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tracking all untracked changes into newborn Mk5.2 hand
Lawproto Nov 25, 2025
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Update docs/hands/hands_mk5.md
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Update docs/hands/hands_mk5_coupling.md
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Update docs/hands/hands_mk5.md
Lawproto Nov 25, 2025
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corrections after considering coupling with ring and pinky
Lawproto Nov 26, 2025
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19 changes: 19 additions & 0 deletions docs/hands/hands_mk5.md
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@@ -1,5 +1,24 @@
# Hand Mk5 joints Specs

## Mk5.2

| Joint number | Motors | Identifier | Type | Parent link | Child link | HW lower limit | HW upper limit | SW low. l. | SW upp. l. | Notes |
|--------------|--------|---------------|------|-----------------|-----------------|----------------|----------------|------------|------------|------------|
| | | l_thumb_add | ROT | l_hand_palm | l_hand_thumb_1 | 0° | 100° | | | T1 in fig. |
| | | l_thumb_prox | ROT | l_hand_thumb_1 | l_hand_thumb_2 | 3.63° | 98° | | | T2 in fig. |
| | | l_thumb_dist | ROT | l_hand_thumb_2 | l_hand_thumb_3 | 0° | 101.78° | | | T3 in fig. |
| | | l_index_add | ROT | l_hand_palm | l_hand_index_1 | 0° | 15° | | | I1 in fig. |
| | | l_index_prox | ROT | l_hand_index_1 | l_hand_index_2 | 5.75° | 98° | | | I2 in fig. |
| | | l_index_dist | ROT | l_hand_index_2 | l_hand_index_3 | 0° | 98.35° | | | I3 in fig. |
| | | l_middle_prox | ROT | l_hand_palm | l_hand_middle_1 | 5.75° | 98° | | | M1 in fig. |
| | | l_middle_dist | ROT | l_hand_middle_1 | l_hand_middle_2 | 0° | 98.35° | | | M2 in fig. |
| | | l_ring_prox | ROT | l_hand_palm | l_hand_ring_1 | 5.75° | 98° | | | R1 in fig. |
| | | l_ring_dist | ROT | l_hand_ring_1 | l_hand_ring_2 | 0° | 98.35° | | | R2 in fig. |
| | | l_pinkie_prox | ROT | l_hand_palm | l_hand_pinkie_1 | 5.71° | 98° | | | P1 in fig. |
| | | l_pinkie_dist | ROT | l_hand_pinkie_1 | l_hand_pinkie_2 | 2.78° | 101.78° | | | P2 in fig. |

> **Note:** Refer to Mk5.1 image.

## Mk5.1

| Joint number | Motors | Identifier | Type | Parent link | Child link | HW lower limit | HW upper limit | SW low. l. | SW upp. l. | Notes |
Expand Down
79 changes: 75 additions & 4 deletions docs/hands/hands_mk5_coupling.md
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Expand Up @@ -92,6 +92,77 @@ Hence we get

$$q_0 = \frac{r_{mot}}{r} \cdot q_{mot} $$

## Mk5.2 coupling variables

The following table describes the coupling variables of the finger mechanisms in the **hand Mk5.2**.

| Name | UoM | | | Values | | | Description |
|-------------|-----|-----------|-----------|------------|----------|-----------|------------------------------------------------------------------------------------|
| | | **THUMB** | **INDEX** | **MIDDLE** | **RING** | **PINKY** | |
| $L_{0x}$ | mm | -5 | -5 | -5 | -5 | -5 | $x$ coordinate of the first end of the leverism |
| $L_{0y}$ | mm | 4 | 4 | 4 | 4 | 4 | $y$ coordinate of the the first end of the leverism |
| $L_{1x}$ | mm | 29.09 | 34.18 | 34.18 | 34.18 | 29.09 | $x$ coordinate of the second end of the leverism |
| $L_{1y}$ | mm | 0.24 | -0.2 | -0.2 | -0.2 | 0.24 | $y$ coordinate of the second end of the leverism |
| $P_{0x}$ | mm | 0 | 0 | 0 | 0 | 0 | $x$ coordinate of the axis of the joint between ground and the first phalanx (origin) |
| $P_{0y}$ | mm | 0 | 0 | 0 | 0 | 0 | $y$ coordinate of the axis of the joint between ground and the first phalanx (origin) |
| $P_{1x}(0)$ | mm | 35 | 40 | 40 | 40 | 35 | $x$ coordinate of the axis of the joint between the first and the second phalanx |
| $P_{1y}(0)$ | mm | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | $y$ coordinate of the axis of the joint between the first and the second phalanx |
| | | | | | | | |
| $q_{0off}$ | deg | -97.54 | -97.54 | -97.54 | -97.54 | -97.54 | Angle of $A-C$ when the finger is in the theoretical zero position (read note 1) |
| $q_{2bias}$ | deg | -162.27 | -156.18 | -156.18 | -156.18 | -162.27 | Angle between $L_1-P_1$ and the horizontal of the second phalanx (read note 2) |
| $q_{1off}$ | deg | 2.45 | 2.15 | 2.15 | 2.15 | 2.45 | Angle of $P_1-P_0$ when the finger is in the theoretical zero position |
| $q_{1bias}$ | deg | -90 | -90 | -90 | -90 | -90 | Angle of $B-P_0$ when the finger is in the theoretical zero position |
| | | | | | | | |
| $q_{0max}$ | deg | -6.42 | -6.42 | -6.42 | -6.42 | -6.42 | Max value of $q_0$, i.e. when the finger is fully closed |
| $q_{1max}$ | deg | 98 | 98 | 98 | 98 | 98 | Max value of $q_1$, same as above |
| $q_{2max}$ | deg | 199.77 | 196.35 | 196.35 | 196.35 | 199.77 | Max value of $q_2$, same as above |
| | | | | | | | |
| $q_{1rest}$ | deg | 3.63 | 5.75 | 5.75 | 5.75 | 5.71* | Rest value for $q_1$ (* read note 3) |
| $q_{2rest}$ | deg | 3.63 | 5.75 | 5.75 | 5.75 | 8.49* | Rest value for $q_2$ (* read note 3) |
| | | | | | | | |
| $k$ | mm | 34.30 | 39.4 | 39.4 | 39.4 | 34.30 | Connecting rod length, $\|L_1-L_0\|$ |
| $d$ | mm | 35.03 | 40.03 | 40.03 | 40.03 | 35.03 | Distance between the two joints, $P_1$ and $P_0$ |
| $l$ | mm | 6.04 | 6.07 | 6.07 | 6.07 | 6.04 | Distance between $L_1$ and $P_1$ |
| $b$ | mm | 6.4 | 6.4 | 6.4 | 6.4 | 6.4 | Distance between $L_0$ and $P_0$ |
| $s$ | mm | 5.5 | 5.5 | 5.5 | 5.5 | 5.5 | Distance between joint $B$ of the connecting rod $A-B$ and joint $P_0$ |
| $t$ | mm | 14.5 | 14.5 | 14.5 | 14.5 | 14.5 | Length of the connecting rod $A-B$ |
| $f$ | mm | 5.5 | 5.5 | 5.5 | 5.5 | 5.5 | Length of the connecting rod $A-C$ |
| $r$ | mm | 8.5 | 8.5 | 8.5 | 8.5 | 8.5 | Length of the connecting rod $D-C$ |
| $r_{mot}$ | mm | 5 | 5 | 5 | 5 | 5 | Distance between the axis of the bushing and the rotational axis of the finger motor |

> **Note 1:** Version Mk5.2 has shifted the hard stop of the rest position to the last moving phalanx. As a consequence, $q_1$ is non-zero when the hand is at rest. Parameters were measured considering the following, physically compenetrating position to stay consistent with the reference system adopted until now. The new rest positions for all the fingers have been stored inside $q_{1rest}$, $q_{2rest}$ (see table).

> **Note 2:** As a consequence of Note 1, $q_{2bias}$ is now better generalised as the angle between $L_1-P_1$ and the horizontal of the second phalanx. This new definition still works with older versions. See image to have a more intuitive notion.

> **Note 3:** Although the pinky is mechanically identical to the thumb, its rest value depends on the ring which is mechanically coupled to.

<p align="center">
<img src= "../img/mk5_2-zero.png"
width= "600">
</p>

<p align="center">
<sub>Theoretical, unreachable zero for Mk5.2</sub>
</p>

<p align="center">
<img src= "../img/mk5_2-true-rest.png"
width= "600">
</p>

<p align="center">
<sub>Actual rest position for Mk5.2</sub>
</p>

<p align="center">
<img src= "../img/mk5_2-q2bias.png"
width= "500">
</p>

<p align="center">
<sub>Generalised definition for q2bias</sub>
</p>

## Mk5.1 coupling variables

The following table describes the coupling variables of the finger mechanisms in the **hand Mk5.1**.
Expand All @@ -103,8 +174,8 @@ The following table describes the coupling variables of the finger mechanisms in
| $L_{0y}$ | mm | 4 | 4 | 4 | 4 | 4 | $y$ coordinate of the the first end of the leverism |
| $L_{1x}$ | mm | 29 | 34 | 34 | 34 | 29 | $x$ coordinate of the second end of the leverism |
| $L_{1y}$ | mm | 0.8 | 0.8 | 0.8 | 0.8 | 0.5 | $y$ coordinate of the second end of the leverism |
| $P_{1x}$ | mm | 35 | 40 | 40 | 40 | 35 | $x$ coordinate of the axis of the joint between the first and the second phalanx |
| $P_{1y}$ | mm | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | $y$ coordinate of the axis of the joint between the first and the second phalanx |
| $P_{1x}(0)$ | mm | 35 | 40 | 40 | 40 | 35 | $x$ coordinate of the axis of the joint between the first and the second phalanx |
| $P_{1y}(0)$ | mm | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | $y$ coordinate of the axis of the joint between the first and the second phalanx |
| | | | | | | | |
| $q_{0off}$ | deg | -97.54 | -97.54 | -97.54 | -97.54 | -97.52 | Angle of $A-C$ when the finger is fully open |
| $q_{2bias}$ | deg | -173.35 | -173.35 | -173.35 | -173.35 | -170.53 | Angle of $L_1-P_1$ when the finger is fully open |
Expand Down Expand Up @@ -137,8 +208,8 @@ The following table describes the coupling variables of the finger mechanisms in
| $L_{0y}$ | mm | 2.85 | 4 | 4 | 4 | 4 | $y$ coordinate of the the first end of the leverism |
| $L_{1x}$ | mm | 11.5 | 24 | 24 | 24 | 19 | $x$ coordinate of the second end of the leverism |
| $L_{1y}$ | mm | 1.5 | 0.8 | 0.8 | 0.8 | 0.5 | $y$ coordinate of the second end of the leverism |
| $P_{1x}$ | mm | 20 | 30 | 30 | 30 | 25 | $x$ coordinate of the axis of the joint between the first and the second phalanx |
| $P_{1y}$ | mm | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | $y$ coordinate of the axis of the joint between the first and the second phalanx |
| $P_{1x}(0)$ | mm | 20 | 30 | 30 | 30 | 25 | $x$ coordinate of the axis of the joint between the first and the second phalanx |
| $P_{1y}(0)$ | mm | 1.5 | 1.5 | 1.5 | 1.5 | 1.5 | $y$ coordinate of the axis of the joint between the first and the second phalanx |
| | | | | | | | |
| $q_{0off}$ | deg | -110.71 | -97.54 | -97.54 | -97.54 | -97.54 | Angle of $A-C$ when the finger is fully open |
| $q_{2bias}$ | deg | -180 | -173.35 | -173.35 | -173.35 | -170.54 | Angle of $L_1-P_1$ when the finger is fully open |
Expand Down
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