Micro Transfer Arm

A Microfactory is a new concept for an extremely miniaturized manufacturing facility that enables dramatic energy and space conservation. As a material transfer and assembly component of a prototype Microfactory, a micro transfer arm that provides 4 DOF and a maximum length of approximately 100mm has been developed.

To achieve a compact-lightweight structure, large workspace and positioning accuracy, the arm is configured as a combination of a SCARA-type manipulator and a parallel mechanism. To enable the arm to perform fine assembly tasks, a 3-axis device that is an integration of a passive compliancer and a force sensor was developed.

Micro transfer arm (maximum length: approximately 100 mm)

• For transfer and assembly tasks of small-lightweight workpieces.
• Maximum length of approximately 100mm.
• 4 degrees of freedom: radial, tangential, vertical translation & yaw rotation.
• Combination of a SCARA-type manipulator and a pantograph-type parallel mechanism.
• By installing servomotors at the base, the middle part of the arm was designed as a slim and lightweight links and passive joints.

• Large workspace (φ200 mm) due to less kinematic restriction compared with small floor space (50 mm×70 mm).

• Rapid motion: maximum speed=0.6 m/s
• High accuracy: deviation for repetitive positioning<10 µm

• Absorption of positional error by passive deformation and sensing of the contact force.
• Deformation of the frame is converted into electric signal by permanent magnets and Hall element.
• Low-cost fabrication of high-aspect 3D structure from thin metal sheet through etching and folding.
• Shaft insertion into the hole (maximum clearance: 28 µm) was achieved using force feedback.

Principle & Structure

Insertion with positional error	Error absorption & Force sensing

ORIGAMI fabrication

Contouring & grooving by etching	Fold	Finish