Give a detailed introduction of SCARA robots in the aspect of their market and rationale. Examples and related data are needed.

 

SCARA Robots are a popular option foKr small robotic assembly applications. SCARA is an acronym for Selective Compliance Articulated Robot Arm, meaning it is compliant in the X-Y axis, and rigid in the Z-axis. The SCARA configuration is unique and designed to handle a variety of material handling operations.

The SCARA's structure consists of two arms joined at the base and the intersection of arms one and two. Two independent motors use inverse kinematics and interpolation at joints J1 and J2 to control the SCARA's X-Y motion. The final X-Y location at the end of arm two is a factor of the J1 angle, J2 angle, length of arm one and length of arm two.

The SCARA robot is one of 3 major classes of robot which Cyan Tec Systems are experienced at integrating, namely:

• Cartesian Robots (Gantry type)
• Six-axis Robots
• SCARA Robots

The selection of which type of robot to choose is not always clear-cut, but Cyan Tec Systems are in a totally unbiased position to recommend the best solution for the particular automation requirement. This article considers the specific case of the SCARA robot and when it is most likely advantageous to use one. In some cases the selection of the most suitable robot is straightforward and in others it is mainly down to a comparison on cost.  SCARA robots normally have up to 4 axes (3 rotation and one Z linear).

Advantages of SCARA robots

The SCARA robot is most commonly used for pick-and-place or assembly operations where high speed and high accuracy is required. Generally a SCARA robot can operate at higher speed and with optional cleanroom specification. In terms of repeatability, currently available SCARA robots can achieve tolerances lower than 10 microns, compared to 20 microns for a six-axis robot. By design, the SCARA robot suits applications with a smaller field of operation and where floor space is limited, the compact layout also making them more easily re-allocated in temporary or remote applications.

The SCARA robot is most commonly used for pick-and-place or assembly operations where high speed and high accuracy is required. Generally a SCARA robot can operate at higher speed and with optional cleanroom specification.

Limitations of SCARA robots

SCARA robots, due to their configuration are typically only capable of carrying a relatively light payload, typically up to 2 kg nominal (10 kg maximum). The envelope of a SCARA robot is typically circular, which doesn't suit all applications, and the robot has limited dexterity and flexibility compared to the full 3D capability of other types of robot. For example, following a 3D contour is something that will be more likely fall within the capabilities of a six-axis robot.

Examples:

1.Screw tightening work using robot vision iVY system

The iVY system highly functionalizes screw tightening work by a SCARA robot

• Various conditions can be handled by adding the iVY system's position detection function.For example, the robot can be easily incorporated in cases such as when the screw hole positions are inconsistent, the workpiece position on the conveyor is not consistent, or when multiple types of workpieces are supplied.
• The iVY system can be calibrated with simple operations. The teaching process can be reduced, so the system startup time can be shortened and labor costs can be reduced, etc.
• 2.Process-to-process transfer using inverse specifications

• Transfer workpieces between processes using the inverse specifications

• The inverse specifications allow the workpiece to be held from below, so the dropping of foreign matter onto the workpiece being transferred can be prevented.
• The robot mechanism performance is equivalent to the standard specifications. The high performance of the YK-XG Series can be utilized.
• Three installation patterns can be selected: the Yamaha Scalar robot's standard floor installation, wall mounting and this inverse specification (*). Yamaha proposes various ideas when designing your system.

• 3.Process-to-process transfer of heavy workpiece

• The timing belt-less drive using the built-in structure realizes a high tolerable inertia for the R axis.
• A large hand can be used with this high tolerable inertia for the R axis. The transferrable quantity per session increases, and attains a higher efficiency.
• With a low inertia, the R axis can be moved with a high acceleration, and the cycle time can be shortened.
• Harmonic gears are adopted for the XYR axis reduction gears.