A Bone Milling Robot for Spinal Surgery1

Because of the high flexibility and low investment costs, industrial robots are increasingly being employed for machining processes. However, milling robots can only be used for applications requiring low accuracy and minor cutting forces. The main reason for this is the low static and dynamic stiffness of the robot structure, which lead to huge deflections of the tool and heavy chatter oscillations, especially when steel is being machined. To extend the areas in which milling robots are applied, a model-based controller to compensate for path deviation has been developed at the Institute of Machine Tools and Industrial Management of TU Munich (iwb). In addition, process-based strategies to reduce chatter have been analyzed. This paper focuses on the dynamic behavior of robots to increase the stability of the cutting process, but it also gives an overview of the design of the controller for static deviation compensation.

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On the tool-path optimization of a milling robot

Computers & Industrial Engineering ◽

10.1016/s0360-8352(02)00118-3 ◽

2002 ◽

Vol 43 (3) ◽

pp. 455-472 ◽

Cited By ~ 30

Author(s):

S.S. Makhanov ◽

D. Batanov ◽

E. Bohez ◽

K. Sonthipaumpoon ◽

W. Anotaipaiboon ◽

...

Keyword(s):

Tool Path ◽

Path Optimization ◽

Tool Path Optimization ◽

Milling Robot

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Design of eddy current dampers for vibration suppression in robotic milling

Advances in Mechanical Engineering ◽

10.1177/1687814018814075 ◽

2018 ◽

Vol 10 (11) ◽

pp. 168781401881407 ◽

Cited By ~ 4

Author(s):

Fan Chen ◽

Huan Zhao

Keyword(s):

Eddy Current ◽

Vibration Suppression ◽

Milling Process ◽

Magnetic Flux Density ◽

Depth Of Cut ◽

Chatter Suppression ◽

Robotic Milling ◽

Eddy Current Damper ◽

Damper Design ◽

Milling Robot

The milling robot normally has a low stiffness which may easily cause chatter during machining. This article presents a novel eddy current damper design for chatter suppression in the robotic milling process. The designed eddy current dampers are installed on the milling spindle to damp the tool tip vibrations. The structural design and the working principle of the eddy current dampers are explained. The magnetic flux density distribution and the magnetic force generation of the designed eddy current damper are analyzed with the finite element method. The tool tip dynamics without and with eddy current dampers are modeled, and the damping performance of the proposed eddy current dampers in the robotic milling process is verified through both simulations and experiments. The results show that the peaks of the tool tip frequency response function caused by the milling tool modes are damped significantly, and the stable depth of cut is improved greatly with eddy current dampers.

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A Compact, Bone-Attached Robot for Mastoidectomy

Journal of Medical Devices ◽

10.1115/1.4030083 ◽

2015 ◽

Vol 9 (3) ◽

Cited By ~ 9

Author(s):

Neal P. Dillon ◽

Ramya Balachandran ◽

J. Michael Fitzpatrick ◽

Michael A. Siebold ◽

Robert F. Labadie ◽

...

Keyword(s):

Computed Tomography ◽

High Speed ◽

Degrees Of Freedom ◽

Compact Bone ◽

Target Volume ◽

Surgical Workflow ◽

The Mean ◽

Milling Robot ◽

High Level ◽

Temporal Bones

Otologic surgery often involves a mastoidectomy, which is the removal of a portion of the mastoid region of the temporal bone, to safely access the middle and inner ear. The surgery is challenging because many critical structures are embedded within the bone, making them difficult to see and requiring a high level of accuracy with the surgical dissection instrument, a high-speed drill. We propose to automate the mastoidectomy portion of the surgery using a compact, bone-attached robot. The system described in this paper is a milling robot with four degrees-of-freedom (DOF) that is fixed to the patient during surgery using a rigid positioning frame screwed into the surface of the bone. The target volume to be removed is manually identified by the surgeon pre-operatively in a computed tomography (CT) scan and converted to a milling path for the robot. The surgeon attaches the robot to the patient in the operating room and monitors the procedure. Several design considerations are discussed in the paper as well as the proposed surgical workflow. The mean targeting error of the system in free space was measured to be 0.5 mm or less at vital structures. Four mastoidectomies were then performed in cadaveric temporal bones, and the error at the edges of the target volume was measured by registering a postoperative computed tomography (CT) to the pre-operative CT. The mean error along the border of the milled cavity was 0.38 mm, and all critical anatomical structures were preserved.

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