What must happen after the robot arrives?
Describe the final action as a verb and an object: deliver a rack, push a tray into a receiver, retrieve a plate from a shelf or place a tube into a fixture. These actions require different mechanisms. The mobile base solves the travel problem; the endpoint mechanism solves the handoff problem.
NIST’s mobile manipulator research treats the mobile base and manipulator as a combined performance-measurement problem. For an OEM, this reinforces the need to specify the complete task rather than infer system performance from separate component specifications.
| Question | Transport platform | Mobile manipulator |
|---|---|---|
| What moves the item at the endpoint? | A person or a defined station mechanism. | An arm with task-specific tooling, potentially with station fixtures. |
| What geometry matters? | Carrier support, route clearance and docking interface. | Those items plus reach, approach, grip geometry and arm travel envelope. |
| What must be coordinated? | Travel, station readiness and transfer acknowledgement. | Base position, arm state, grip state and station permission as well. |
| What is the acceptance task? | Confirmed delivery of the defined carrier. | Confirmed pickup and placement under defined conditions. |
When can a simpler handoff be sufficient?
A laboratory may have accessible carrier-height stations or operators who already load the next stage. If the transfer task ends at those locations, an arm may add cost and verification work without eliminating another useful operation.
A fixed handoff can still need careful engineering. Receiver capacity, alignment, load detection and recovery after an interrupted transfer remain important. Simpler mechanics do not remove the need for a complete state definition.
When is an arm worth evaluating?
Evaluate manipulation when the endpoint requires a defined reach, orientation change or pickup that cannot be provided by the chosen transport interface. Check whether the station is accessible to the tooling and whether the item has repeatable gripping surfaces.
Work through difficult cases before a build: a rack shifted within tolerance, an empty pickup location, a partially gripped item or a station that becomes unavailable. Define a safe recovery process and the controller that authorizes it.
Which endpoint actions actually require manipulation?
We compare the endpoint actions below before choosing the handling mechanism. The station geometry and permitted load determine whether a guided transfer or a robotic arm is appropriate.
| Endpoint task | Architecture to evaluate | Unresolved engineering question |
|---|---|---|
| Carry a closed rack between accessible buffers | Mobile base with a defined manual or fixed transfer interface. | Can the buffers accept the rack with the proposed height, orientation and loading method? |
| Retrieve a plate from different shelf positions | Mobile manipulator with a task-specific tool and referencing method. | Are all required poses reachable, and can the object be located and retained reliably? |
| Push a carrier into a constrained fixture | Docked platform with a guided transfer mechanism, or an arm if the task demands it. | Can mechanical guidance achieve the accepted placement condition without a more complex handling action? |
Document the reference chain from the mobile base through the arm and tool to the object and station. Repeatability of a single component does not, by itself, answer whether that chain meets a placement requirement. Agree the method for evaluating the assembled task and the adjustments permitted during commissioning.
Manufacturing review inputs
- Drawings of the base, arm mount, station and carrier.
- Item and tooling mass, reach requirements and structural load cases.
- Cable and hose routing through the full intended motion.
- Travel posture and restraint during transport.
- Permitted operating states and interlocks between controllers.
- Task-level acceptance method and representative fixtures.
Which assumptions should be challenged?
An arm’s specified repeatability is not a guarantee that the full robot will pick from every station. The error budget also includes the base, mounting structure, station fixture and item variation. Similarly, a collaborative component does not establish the safety of a whole mobile task.
We manufacture the body, platforms, grippers and fixtures, then integrate the selected base and arm, firmware connections and platform interface. Your team connects its scheduling software. We agree the hardware acceptance tests with you; your team verifies the laboratory workflow.
Common questions
Can an arm be added later?
Possibly, but the initial base and structure must accommodate the future loads, envelope, power, interfaces and verification needs. A mounting hole pattern alone is insufficient planning.
Can one station use manual handoff and another use an arm?
That is a possible workflow arrangement. Define the states, permissions and acceptance criteria for each station separately.
Which specification should be agreed first?
Begin with the actual item, endpoint action and acceptance condition. They determine the required configuration.
Can improved fixtures remove the need for an arm?
Sometimes. A guided carrier and consistent station geometry may support the required transfer with a simpler mechanism. Evaluate loading access, variation, throughput and recovery before fixing the architecture.
Should transport and manipulation be commissioned separately?
Separate checks can help diagnose each subsystem, but acceptance should also cover the complete sequence with the agreed carrier, station and configuration. Define which checks are repeated after installation or a change.