Typical 6-axis robotic arms (traditional and cobotic), weighing about 50kg, have a repeatability of ±0.03mm to ±0.05mm and payload of 10kg to 20kg.
Repeatability is critical for process reliability and depends on static/dynamic load, frame creep, assembly shift, bearing wear, transmission backlash, thermal expansion, and more.
Standalone robotic arms are best for full-utilization processes (100% duty cycle) where limited reach (immobile base) is a non-factor for continuously performing each nearby task. The fixed base and concise joint geometry also provide the best possible rigidity for high-precision/high-payload tasks.
Machine vision enables robots to not only sort different objects (object classification) and pick up randomly scattered objects (visual-spatial analysis; object centerpoint/orientation/features), but also index to state-variations of key objects (ex. resolve current floor position of input-material cart) and interpret environmental context in real-time for autonomous decision-making (ex. zone-based task selection).
Mobile manipulators are one or more robotic arms on an automous guided/intelligent vehicle. They are less precise than standalone arms but can perform a complete chain of tasks at different locations as a single robot with dynamic task-to-task indexing and zone-to-zone mobility with minimal point-in-time footprint. Therefore mobile manipulators are best for low-to-medium volume processes prioritizing cost-effective A-to-Z automation.
Humanoid robots are a type of vision-guided, audio-enhanced mobile manipulator. The humanoid form factor provides the most intuitive, ergonomic tele-operation capability and best spatial compatibility with existing tools/machines/processes that already work with human operators. Advanced visual-auditory-spatial control designs help streamline and automate the setup process with greater variation tolerance. Humanoid robots offer the easiest user experience, the most versatile functionality, with excellent dual-arm compatibility for humanoid tasks but at a price premium.