List of criteria to look at before buying a robot arm

List of criteria to look at before buying a robot arm

This entry was posted in Comparisons, tests and products presentation on by Vanessa Mazzari.


Robot arms that Génération Robots distribute are aimed at laboratories, R&D units, universities. We are providing in this post a comparison table between our four large size, ROS compatible, robot arms (6 and 7 DoF).

Which applications for robot arms in the research field?

In a laboratory or in a R&D unit, robot arms are used in different study fields:

  • Exploration (terrestrial or space-based), analysis or surveillance – a robot arm can be set up on a mobile base
  • E-health, robot arms are used to experiment on smart prothesis prototypes (i.e. a mind-controlled robot arm)
  • Care assistant for elderly or disabled people, the robot arm will be trained to carry out everyday tasks (make some coffee, fold the laundry…)
  • Reliability tests of manufactured products (interactive fabric, smartphone screens…)
Sawyer robot arm on a mobile robot

Robot arms with 6DoF or 7DoF

One of the first criteria to look at when choosing a robot arm is the number of degrees of freedom (DoF). DoF refers to the specific number of axes that a rigid body is able to freely move in 3D space. A 6DoF robot arm can reach any given point in space, with any given orientation.

A 6DoF robot arm can perform a wide variety of tasks:

  • Grasp a tool at the far end of the handle, flip it and put it back
  • Open a drawer, grasp an item and close the drawer
  • Write down on a desk or on a wall

A 7DoF robot arm is the most similar to a human arm. It replicates the human arm motion the best. will replicate human movements Un bras robotique doté de 7 degrés de liberté (DoF) est celui qui se rapproche le plus du bras humain. More agile and faster than a 6DoF robot arm, it can reach inaccessible spots that a 6DoF robot arm can’t.

Strength and reach

The strength (maximum payload) and the maximum reach are the next two criteria that will require your attention.
Think about the project you will be working with your robot arm. Will the robot have to carry heavy items or apply a force to a mechanism? Be aware that a robot with a higher maximum payload will lose in accuracy.
The robot reach is the distance from the center of the robot to the fullest extension of the robotic arm.

Speed and accuracy

Accuracy is an important consideration if the robot arm have to interact with small parts or tiny items.
A robot repeatability (how well the robot can reproduce the same move in unchanged conditions) will be an important criteria during a pick and place task in a laboratory. If the robot is used in an experiment about home care, a high maximum speed will probably not be a major consideration.

Franka Emika Panda robot used as a care robot

Other decision-making criteria in the purchase of a robot arm

We added to our “checklist” five other decision-making criterias:

  • Number of grippers available for the robot
  • ROS compatibility
  • Is it a collaborative robot? (intended to work alongside and/or directly interact with humans in a shared space)
  • IP classification (waterproof, dustproof)
  • CE marking (conformity of the robot with EU legislation)
  • Budget

Comparison table of our four collaborative robots

Below is a comparison table of our four large size robotic arms that includes the listed criteria:

Rethink Robotics
Rethink Robotics
  Gen3 Gen3 Lite M1013 Sawyer Baxter xArm
Degrees of freedom 6 DoF or 7 DoF 6 DoF 6 DoF 7 DoF 7 DoF 5, 6 or 7 DoF
Maximum payload 4 kg 0.5 kg 10 kg 4 Kg 2.2 kg 3 kg
Maximum reach 891 mm (6DoF)
and 902 mm (7 DoF)
760 mm 1300 mm 1260 mm 1210 mm 700 mm
Repeatability ± 0.15 mm ± 0.15 mm ± 0.1 mm ± 0.1 mm ± 0.1 mm ± 0.1 mm
Speed 50 cm/s 25 cm/s 1m/s 1.5 m/s 1m/s 1m/s
Available grippers 1 1 ± 20 ± 10 ± 10 3
ROS compatible Yes Yes Yes Yes Yes Yes
Collaborative robot Yes Yes Yes Yes Yes Yes
IP classification IP33 IP22 IP54 IP54 IP50 IP22
CE marking Yes Yes Yes Yes No No
Budget 29 500,00€ TTC (6DoF)
35 000,00€ TTC (7DoF)
18 000,00€ TTC 38 400,00€ TTC 42 000,00€ TTC 43 200,00€ TTC 6 600,00€ TTC (5DoF)
9 600,00€ TTC (6DoF)
11 400,00€ TTC (7DoF)