# Linear Bot
✓ Python SDK
✓ Full Mobile Manipulation
✓ Height Adjustment
**Linear Bot** is the [Flow Base](/products/flow-base) combined with a vertical linear rail actuator. The linear rail adds a height axis to the omnidirectional base, enabling the mounted YAM arm to reach objects at varying heights — from floor-level to shelf-height — without repositioning.
## System Architecture
```
┌─────────────────────────┐
│ YAM Arm │ ← 6-DOF manipulation
├─────────────────────────┤
│ Linear Rail │ ← Vertical axis (Z height)
├─────────────────────────┤
│ Flow Base │ ← XY + rotation (holonomic)
└─────────────────────────┘
```
The three subsystems are controlled together through a unified Python API, giving the robot **9 degrees of freedom** (6-DOF arm + 3-DOF mobile base including linear rail).
## Key Features
- **Vertical height axis** — linear rail extends and retracts under API or remote control
- **Limit switches** — hardware safety stops at both rail ends; auto-home on initialization
- **Brake management** — brake automatically released on init, engaged on shutdown
- **Integrated API** — 4D base velocity commands `[x, y, θ, rail_vel]`
- **Safety timeouts** — both base and rail stop after 0.25 s without a heartbeat
## Specifications
| Parameter | Value |
|-----------|-------|
| Mobile base | Flow Base (holonomic) |
| Vertical actuator | Linear rail with DM-series motor |
| Arm (typical) | YAM or YAM Pro |
| Total DOF (arm + base + rail) | 9 |
| Rail control | Velocity [rad/s] |
| Rail velocity timeout | 0.25 s |
| Rail home | Lower limit (on init) |
## Photos & Videos
## Python API
```python
from i2rt.flow_base.flow_base_client import FlowBaseClient
client = FlowBaseClient(host="172.6.2.20", with_linear_rail=True)
# Move forward + raise rail simultaneously
client.set_target_velocity([0.1, 0.0, 0.0, 0.05], frame="local")
# x y θ rail_vel
# Get rail position and limit switch states
state = client.get_linear_rail_state()
print(state) # {'position': ..., 'velocity': ..., 'limit_switches': ...}
# Stop rail
client.set_linear_rail_velocity(0.0)
```
## Important Notes
::: warning Auto-homing on init
The linear rail homes to the **lower limit switch** on every initialization. Ensure there is clearance below the carriage before powering on.
:::
::: tip Stopping the rail
Always set velocity to `0.0` to stop the rail. Do not try to engage the brake directly — the system manages brake state automatically.
:::
## Pricing
Starting at **$18,999**. Contact [sales@i2rt.com](mailto:sales@i2rt.com) for configuration options.
## See Also
- [Flow Base](/products/flow-base) — base-only configuration
- [Flow Base API](/sdk/flow-base)
- [YAM Arm Series](/products/yam)