Advantages and Disadvantages of Low-DOF Robots

FANUC R2000ib 125L R30ia Motoman MA1400 FANUC M710ic 50 Motoman HP6 NX100 FANUC Arcmate 120ic
Low-DOF (degree of freedom) robots are those with fewer than six axes. Typical low-DOF robots used in manufacturing consist of three-axis, four-axis, and five-axis configurations and may be delta, SCARA, gantry, or articulated robot types. The FANUC M410ic/185 and Lr Mate 200id/7H are both considered low-DOF articulated robots. Low-DOF robots can be used to automate simple and highly repetitive applications. Below is a look at some of the advantages and disadvantages of automating with a low-DOF robot.

Advantages


  • • Less Expensive - Low-DOF robots tend to be less expensive to implement. The more axes a robot has the more hardware and integration will be needed for implementation. The more straightforward an application is the less engineering there will be involved to automate it, lowering integration costs.

  • • Easier to Program - Since low-DOF robots have fewer axes they tend to be easier to program and operate. Fewer axes means these robots have fewer degrees of freedom meaning less motions will need to be coordinated. The simplicity of low-DOF robot applications also makes programming easier and can be done by using a teach pendant as opposed to other programming methods that may be at an additional cost.

  • • Extra Stability - Low-DOF articulated robots such as four-axis and five-axis models are ideal for heavy lifting applications such as automated palletizing. Having fewer axes can provide the four axis robot with greater stability since its range of motion is more limited. The four-axis FANUC M410ib/300 is one of the top palletizing robots as its axis configuration provides extra stability for lifting and lowering heavy pallets.

  • • Fast Operation - Many low-DOF robots are capable of extremely fast operating speeds. With a more limited range of motion, there is less variability with movements allowing robots to operate at fast speeds since the same motions are repeated over and over.

  • • Eases Automation of Simple Applications - When selecting an industrial robot, it is important to have an adequate number of axes for your application. Having more axes than needed is not necessarily bad but can add additional costs and complexity. If your application is repeatable and straightforward a low-DOF robot should be appropriate and will ease the automation process. However, if in the future your application may become more complex than it may be best to invest in a six-axis robot to allow for future changes.

Disadvantages


  • • Limited Range of Motion - One of the biggest disadvantages of low-DOF robots is their limited range of motion. If manufacturing processes were to change in the future, your low-DOF robot may not have the degrees of freedom needed to effectively adapt to the changes. For instance, if parts needs to be picked up and placed on a conveyor then a low-DOF FANUC M710ic/50H could be used. However, if processes change and the parts need to be reoriented before being placed on the conveyor, then a six-axis FANUC M-710ic/50 would be needed.

  • • Less Versatile - Low-DOF robots are also less versatile than six-axis robots. Six-axis robots can automate just about any production related task regardless of complexity. Low-DOF robots are limited in their scope of complexity for applications they can automate.


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